Electrophotographic image forming apparatus

0001The present invention relates to a supporting member according to the preamble of claim 1 usable with an electrophotographic image forming apparatus.

[BACKGROUND ART]

0002Heretofore, in the field of an image forming apparatus which uses an electrophotographic image forming process, the process cartridge which includes a photosensitive drum and a developing roller which acts on the photosensitive drum and a developing unit which contains a developer (toner) to be used for the image formation as a unit is known. A developing cartridge type using the developing unit which does not include the photosensitive drum is also known. According to these cartridge types, a maintenance operation of a device can be carried out by the user without a service person, in effect. For this reason, these cartridge types are widely used for the electrophotographic image forming apparatus.

0003It is also known that a drawer for carrying the process cartridge or the developing cartridge is provided, and the exchange of the cartridge is capable by drawing this drawer from the inside of the main assembly to a predetermined position. According to this technique, the user can supply the developer easily, in effect.

0004Here, when the image formation is carried out by the image forming apparatus, the developing roller in the developing unit is in the state of being urged toward the photosensitive drum at a predetermined pressure. In a contact-type developing system in which the developing roller is contacted to the photosensitive drum during the developing operation, an elastic layer of the developing roller is in contact to a surface of the photosensitive drum at the predetermined pressure.

0005Therefore, when the developing unit is used for a long term in the state that it is mounted to the main assembly of the apparatus, the elastic layer of the developing roller may be deformed. This will result in occurrence of non-uniformity in the image by the developing operation. In addition, since the developing roller is in contact with the photosensitive drum, the developer is deposited on the photosensitive drum from the developing roller unnecessarily. Furthermore, since the photosensitive drum and the developing roller are contacted with each other and rotated even when the developing operation is not carried out, and therefore, the deterioration of the developer and the developing roller is accelerated as the case may be.

0006In order to suppress the acceleration of the deterioration, <patcit id="pcit0001" dnum="JP2007213024A"><text>JP 2007-213024 A</text></patcit> discloses a mechanism by which the developing roller is spaced from the photosensitive drum when the image formation is not carried out.

0007In such a prior-art, a member (movable member) movable between a position for contacting the developing roller to the photosensitive drum and a position for spacing them is provided in a main assembly side of the apparatus. When a drawer member (tray) carrying the cartridge photosensitive drum and the developing roller enters the main assembly of the apparatus, the movable member is in the position away from a movement path of the drawer member. By a door being closed after the drawer member is inserted to a predetermined position in the main assembly of the apparatus, the movable member moves toward the cartridge carried on the drawer member to space the developing roller from the photosensitive drum.

0008However, in such conventional example, the movable member is provided in the main assembly side of the apparatus. Therefore, when the drawer member is moved into the main assembly of the apparatus, it is required that the movable member is retracted to the position not interfering with the drawer member. In addition, in order to space the developing roller from the photosensitive drum, it is necessary to move the movable member to the position of the cartridge on the drawer member. For this reason, the space is required in the main assembly of the apparatus in order to permit the movement of the movable member from the main assembly side of the apparatus to the cartridge position in the drawer member. This impedes downsizing of the main assembly of the apparatus.

0009<patcit id="pcit0002" dnum="US2007147887A1"><text>US 2007/147887 A1</text></patcit> shows a generic supporting member according to the preamble of claim 1. This supporting member is usable with an image forming apparatus for forming an image on a recording material, the image forming apparatus including a plurality of developing device coupling members and a door for opening and closing a main assembly opening of a main assembly of the apparatus, said supporting member being movable through the main assembly opening between (i) an inside position in which said supporting member is inside the main assembly and (ii) an outside position in which said supporting member is outside the main assembly. The supporting member comprises a plurality of photosensitive drums; and a mounting portion for dismountably mounting a plurality of developing cartridges, each of the plurality of developing cartridges including a developing roller configured for contact with one of said plurality of photosensitive drums to develop an electrostatic latent image formed on said photosensitive drum and a coupling member for transmitting a driving force for rotating the developing roller.

0010Further supporting members according to the prior art are shown in <patcit id="pcit0003" dnum="US2007077086A1"><text>US 2007/077086 A1</text></patcit> and <patcit id="pcit0004" dnum="EP1347344A2"><text>EP 1 347 344 A2</text></patcit>.

Summary of the Invention

0011It is the object of the present invention to further develop a supporting member according to the preamble of claim 1 such that layout thereof is improved and the load for moving the supporting member is reduced.

0012The object of the present invention is achieved by a supporting member, usable with an image forming apparatus for forming an image on a recording material, having the features of claim 1.

0013Further developments of the present invention are defined in the dependent claims.

0014It is an advantage of the present invention to provide a drawer member (supporting member) carrying a photosensitive drum and a developing unit, which is insertable into a main assembly of an electrophotographic image forming apparatus such that a developing roller and the photosensitive drum can be contacted and spaced relative to each other. Further, since the insertable drawer member comprises a contacting and spacing member as such, its size and thus overall size of the electrophotographic image forming apparatus to which the drawer member is inserted can be downsized.

0015In the following, embodiments of the present invention will be described in detail referring to the accompanying drawings. The dimensions, materials, shapes, positional relationships of the constituent elements of the embodiments are not restrictive to the present invention unless otherwise stated.

(Embodiment 1)

0016Referring to <figref idref="f0001 f0018">Figure 1 - Figure 21</figref>, an electrophotographic image forming apparatus (image forming apparatus) according to Embodiment 1 of the present invention will be described.

<General arrangement of image forming apparatus>

0017Referring to <figref idref="f0001">Figures 1</figref> and <figref idref="f0002">2</figref>, the description will be made as to the general arrangement of the image forming apparatus according to Embodiment 1 of the present invention. <figref idref="f0001">Figure 1</figref> is a schematic sectional view of the image forming apparatus according to Embodiment 1 of the present invention. <figref idref="f0002">Figure 2</figref> is a schematic sectional view illustrating the state that the drawer unit in the image forming apparatus according to Embodiment 1 of the present invention is drawn.

0018In an image forming apparatus 100 according to this embodiment, the four electrophotographic photosensitive drums (photosensitive drums 1) juxtaposed horizontally is employed. The photosensitive drum 1 is rotated in the clockwise direction in <figref idref="f0001">Figure 1</figref> by unshown driving means.

0019The image forming apparatus 100 includes the charging means 2, a scanner unit 3, a development unit 4y, 4m, 4c, 4k, and the electrostatic transfer means 5 and so on as electrophotographic image forming process means, in addition to the photosensitive drum 1. The developing units 4y, 4m, 4c, 4k maybe simply called developing unit 4 where doing so is clear, although y represents yellow; m represents magenta; c represents cyan; and k represents black.

0020Here, the charging means 2 has the function of charging a surface of the photosensitive drum 1 uniformly. The scanner unit 3 projects a laser beam onto the photosensitive drum 1 on the basis of image information to form an electrostatic latent image on the surface of the photosensitive drum 1. The developing unit 4 develops the electrostatic latent image formed on the surface of the photosensitive drum 1 using the toner which is a developer. The electrostatic transfer means 5 transfers a toner image on the photosensitive drum 1 onto a sheet material S as a recording material which is a transfer member. Specific examples of sheet material S include the paper, an OHP sheet, and cloth.

0021The image forming apparatus 100 includes cleaning means 6 for removing the toner which remains on the surface of the photosensitive drum after the transferring 1. Furthermore, the image forming apparatus 100 further includes cleaning means 7 for removing the residual toner deposited on the transfer belt 11 below an electrostatic transfer belt (transfer belt 11) as a transfer member which constitutes electrostatic transfer means 5.

0022The photosensitive drum 1 includes an aluminum cylinder and an organic photoconductor layer (OPC photosensitive member) applied on an outer surface thereof, for example. The photosensitive drum 1 is supported by an unshown supporting member rotatably at the opposite ends thereof. One of the ends is provided with an unshown drum coupling for receiving a driving force from a driving motor (unshown). By this, the photosensitive drum 1 receives the driving force of the driving motor through the drum coupling to rotate clockwisely in <figref idref="f0001">Figure 1</figref>.

0023The charging means 2 according to this embodiment is means of a contact charging type. More specifically, the charging means 2 is an electroconductive roller in the form of the roller and contacts to the surface of the photosensitive drum 1. A charging bias voltage is applied to this roller, by which the surface of the photosensitive drum 1 is charged uniformly.

0024The scanner unit 3 is disposed above the photosensitive drum 1. In the scanner unit 3, the image light (laser beam) corresponding to an image signal is emitted from an unshown laser diode and it is incident on the surface of the charged photosensitive drum 1. By this, the electrostatic latent image corresponding to the image signal is formed on the surface of the photosensitive drum 1.

0025The developing units 4 include the toner containers 41y, 41m, 41c, 41k which accommodates the yellow, the magenta, the cyan, and the black toner, respectively. The toner containers 41y, 41m, 41c, 41k are the developer accommodating portions which accommodate the developer (toner) to be supplied to the developing roller 40. The toner in the toner containers 41y, 41m, 41c, and 41k is fed to a toner supplying rollers43. The toner is applied to the outer periphery of the developing roller 40, and the charge is applied to the toner, by the toner supplying roller 43 and a developing blade 44 press-contacted to an outer periphery of the developing roller 40.

0026By applying a developing bias to the developing roller 40, the toner is deposited on a latent image formed on the photosensitive drum 1 to form the toner image. The opposition contact of the developing roller 40 is carried out to the photosensitive drum 1. Here, the developing unit 4 and the photosensitive drum 1 form integral process cartridge P (Py, Pm, Pc, Pk). In the process cartridge P, the toner is consumed with usage, and when the lifetime ends, the process cartridge P can be exchanged (so-called cartridge type).

0027As shown in <figref idref="f0001">Figure 1</figref>, the image forming apparatus 100 includes the transfer belt 11 contacted to the photosensitive drum 1. By the transfer belt 11, the sheet material S is fed to a transfer position, where the toner image formed on the surface of the photosensitive drum 1 is transferred.

0028The inside of the transfer belt 11 is provided with a transfer roller 12 in a position opposed to the photosensitive drum 1. From the transfer roller 12, positive polarity charge is applied to the sheet material S through the transfer belt 11. By this, the toner image (developer image) on the photosensitive drum 1 is transferred to the sheet material S.

0029The image forming apparatus 100 includes a feeding portion 16 for feeding the sheet material S to an image forming station. The feeding portion 16 includes a feeding cassette 17 for accommodating a plurality of sheet S. At the time of the image formation, a feeding roller 18 and a registration roller couple 19 rotate in accordance with the image forming operation. By this, the sheet material S is fed one by one from the cassette 17. In synchronism with the rotation of the transfer belt 11 and the toner image, the sheet material S is fed by the registration roller pair 19 to the transfer belt 11.

0030Furthermore, the image forming apparatus 100 includes a fixing portion 20 for fixing a plural color toner image transferred onto the sheet material S. The fixing portion 20 comprises a rotatable heating roller 21b and a pressing roller 21a press-contacted to it. While the sheet material S onto which the toner image on the photosensitive drum 1 is transferred is nipped between the heating roller 21b and the pressing roller 21a, it is fed, during which the heat and a pressure are applied to the toner. By this, the plural color toner image is fixed on the surface of the sheet material S.

0031An image forming process is as follows. When the image forming operation is started, the photosensitive drum 1 is rotated. The charging means 2 applies the charge uniformly to the surface of the photosensitive drum 1, and the scanner unit 3 exposes the surface of the photosensitive drum 1 to the image light in response to the image signal to form an electrostatic latent image on the surface of the photosensitive drum 1. The developing roller 40 develops the electrostatic latent image (With the toner).

0032On the other hand, to the sheet material S fed by the transfer belt 11 from the feeding portion 16, the toner images formed on the surfaces of the photosensitive drums 1 is sequentially transferred by the electric fields formed between the photosensitive drums 1 and the transfer rollers 12. The sheet material S onto which the four color toner images are transferred is fed to the fixing portion 20. A color image is fixed with the fixing portion 20, and the sheet material S is discharged from a discharging portion 24 to an outside of the device by a discharging roller pair 23.

<Drawer member (supporting member)>

0033A drawer member 13 will be described. It is a supporting member, and is movable between an inside position dismountably supporting the process cartridge and an outside position of the outside of the main assembly.

0034Here, in this embodiment, the main assembly is the portion other than at least drawer member 13 and the members (parts) which are detachably mountable thereto or fixed thereto, among the various members (parts) which constitute the image forming apparatus 100.

0035As shown in <figref idref="f0002">Figure 2</figref>, the drawer member 13 is movable linearly in the substantially horizontal direction (arrows D1 and D2 directions) relative to the main assembly (insertable and drawable). The drawer member 13 can be moved to the position (<figref idref="f0001">Figure 1</figref>) in which it is accommodated in an inside of the main assembly and the position (<figref idref="f0002">Figure 2</figref>) in which it is drawn to an outside the main assembly.

0036In the state that the drawer member 13 is in a drawn-out position, the process cartridges P (Py, Pm, Pc, Pk) is mounted by the user to the drawer member 13 in the substantially vertical direction (the direction of arrow C in <figref idref="f0002">Figure 2</figref>). In the process cartridge P mounted in this manner, a longitudinal direction (an axial direction of the developing roller 40) thereof is perpendicular to a movement direction of the drawer member 13. The four process cartridges Py, Pm, Pc, Pk are juxtaposed in the movement direction of the drawer member 13.

0037In the state that such process cartridges P are mounted to the drawer member 13, they are moved into the main assembly with the drawer member 13. In the state that the drawer member 13 is in the main assembly, when a door 10 is closed, all the process cartridges are mounted to the predetermined positions in the main assembly P.

0038In this manner, according to the image forming apparatus 100 according to this embodiment, four process cartridge Ps can be mounted into the main assembly all together, and four process cartridges Ps can be drawn all together to the outside of the main assembly. Therefore, the operability in the exchange of process cartridge P is excellent, as compared with the case in which the process cartridges are mounted into the main assembly individually.

<Mounting portion of drawer member (supporting member)>

0039Referring mainly to <figref idref="f0003">Figures 3 and 4</figref>, the structures of the mounting portion for the drawer member 13 in the main assembly will be described. <figref idref="f0003">Figures 3 and 4</figref> are a perspective views illustrating the mounting portion for the drawer member in the main assembly of the image forming apparatus according to Embodiment 1 of the present invention. In <figref idref="f0003">Figures 3 and 4</figref>, the scanner unit 3 and so on are omitted among the members (parts) which constitute the main assembly, for better understanding of the structure of the mounting portion. <figref idref="f0003">Figure 3 and Figure 4</figref> are the perspective views as seen in different directions.

0040On an inner wall surface of a main assembly frame, the pair of guide portions 14R, 14L which guide the movement direction of the drawer member 13 is provided opposed to each other. The guide portions 14R, 14L have the function of guiding the portions-to-be-guided 13a, 13b, 13c, and 13d (<figref idref="f0004">Figure 5</figref> and <figref idref="f0005">Figure 6</figref>) of the drawer member 13 as will be described hereinafter, and have a channel-like section. The guide portions 14R, 14L are extended in the substantially horizontal direction from the neighborhood of an entrance of the main assembly (neighborhood of the door 10) to a rear side, so that the drawer member 13 can be guided from the position for drawing to an outside of the main assembly to the position of being accommodated in the inside of the main assembly.

0041Above the guide portions 14R, 14L, urging members 65, 66 for pressing and positioning the process cartridge P to the predetermined position is provided. These urging members 65, 66 press process cartridge P, by moving downwardly with the driving force from a main assembly side, and, thereby to position the process cartridge P in the predetermined position in the main assembly.

0042As shown in <figref idref="f0003">Figure 4</figref>, below a guide portion 14L, a drum coupling member 25 for transmitting a drive to a photosensitive drum 1 and a development coupling member 26 for transmitting the drive to the developing roller 40 are provided, and they are disposed at equal intervals in the horizontal direction. The drum coupling member 25 and the development coupling member 26 transmit the driving forces from an unshown driving source to the process cartridge P. In the state where the door 10 is opened, the drum coupling member 25 and the development coupling member 26 are in the state of retracting in the inside, and they enter into process cartridge P in interrelation with the closing operation of the door 10.

0043As shown in <figref idref="f0003">Figure 4</figref>, furthermore, the rear side of the guide portion 14L is provided with a driving gear 46 for applying the driving force for moving the contacting and spacing member 42 as will be described hereinafter.

<Drawer member (supporting member)>

0044The drawer member 13 will be described in detail referring mainly to <figref idref="f0004">Figures 5</figref> and <figref idref="f0005">6</figref>. <figref idref="f0004">Figures 5</figref> and <figref idref="f0005">6</figref> are perspective views of the drawer unit in the image forming apparatus according to Embodiment 1 of the present invention. <figref idref="f0004">Figure 5</figref> and <figref idref="f0005">Figure 6</figref> are the perspective views, as seen from the different directions.

0045Four corners of the drawer member 13 are provided with the portions-to-be-guided 13a, 13b, 13c, 13d for being guided by the guide portions 14R, 14L of the main assembly. The portions-to-be-guided 13a, 13c are guided by the guide portion 14R, and the portions-to-be-guided 13b, 13d is guided by the guide portion 14L. The portions-to-be-guided 13a, 13b project from the outside of a side surface, and are extended in a drawing direction so that the drawer member 13 does not incline in the drawn-out position. The portions-to-be-guided 13c, 13d have cylindrical shapes and project from the outside of the side surface.

0046The one end portion of the drawer member 13 is provided with a grip portion 28 for the convenience at the time of the user operating the drawer unit U1.

0047Furthermore, the drawer member 13 is provided with the mounting portions 13f for mounting the process cartridge s P, as will be described hereinafter in an array. A partition plate 13g is provided between the mounting portions 13f, and a rough index at the time of mounting process cartridge P is provided. Lower portions of the mounting portions 13f are provided with opening portions 13e, respectively. Through these opening portions 13e, the photosensitive drum 1 provided in the process cartridge P can be contacted to the transfer belt 11.

0048The one-end portions and the other end portions of the mounting portion 13f is provided with the guide portions 13h, 13i, 13j, 13k for mounting the process cartridge s P to the inside of the drawer member 13. The lower portions of the guide portions 13h, 13j are provided with positioning portions 13h1, 13j1 for positioning the process cartridge P relative to the drawer member 13.

0049As shown in <figref idref="f0004">Figure 5</figref>, the drawer member 13 is provided with an opening portion 13m for the entrance of the drum coupling member 25 and an opening portion 131 for the entrance of the development coupling member 26. The drum coupling member 25 and the development coupling member 26 enter the opening portion 13m and the opening portion 131 in interrelation with the closing operation of the door 10. The drum coupling member 25 and the development coupling member 26 which entered these opening portions 13m, 131 engage with the coupling member of the process cartridge P to enable the transmission of the drive to the process cartridge P.

0050One of the side surfaces of the drawer member 13 is provided with a contacting and spacing member 42. The contacting and spacing member 42 is extended along the movement direction of the drawer member 13, and is movable in the movement direction (direction of arrow D in <figref idref="f0004">Figure 5</figref>) of the drawer member 13. A rear end portion of the contacting and spacing member 42 is provided with a rack portion 42a as a driving force receiving portion for receiving the driving force for the movement of the contacting and spacing member 42 from the driving gear 46 (<figref idref="f0003">Figure 4</figref>).

0051The contacting and spacing member 42 is provided with a projection-recess configuration (first projection (force applying portion) 42b, second projection (force applying portion) 42c, and recess 42d) along the longitudinal direction thereof. The first projection (force applying portion) 42b of the contacting and spacing member 42 has a function of spacing the photosensitive drum 1 from the transfer belt 4. The second projection (force applying portion) 42c further projects beyond a first projection 42b, and has the function of spacing the developing roller 40 from the photosensitive drum 1. The details thereof will be described hereinafter. The recess 42d recessed from the projections is provided between the first projection 42b and the second projection 42c.

0052As has been described in the foregoing, the drawer unit U1 comprises the drawer member 13 and the contacting and spacing member 42.

<Process cartridge>

0053Referring to <figref idref="f0006 f0007">Figure 7 - Figure 9</figref>, the description will be made as to the process cartridge P mounted to the drawer member 13. <figref idref="f0006">Figure 7</figref> is a schematic sectional view of the process cartridge according to Embodiment 1 of the present invention. <figref idref="f0006">Figure 8</figref> is a perspective view of the process cartridge according to Embodiment 1 of the present invention. <figref idref="f0007">Figure 9</figref> is a perspective view illustrating the state that the process cartridge according to Embodiment 1 of the present invention is mounted to the drawer unit (drawer member).

0054The process cartridge P comprises a photosensitive member unit 8 and developing unit 4. The photosensitive member unit 8 comprises the photosensitive drum 1, charging means 2, cleaning means 6, and a residual toner container 30 for containing the toner removed by the cleaning means 6. The developing unit 4 comprises the developing roller 40, a toner supplying roller 43, a developing blade 44, and the toner container 41 which contains the toner used for the image formation.

0055As has been described hereinbefore, the toner in the toner container 41 is fed to the toner supplying roller 43. By the toner supplying roller 43 and the developing blade 44 press-contacted to the outer periphery of the developing roller 40, the toner is applied to the outer periphery of the developing roller 40, and the charge is applied to the toner. By applying the developing bias from the main assembly to the developing roller 40, the toner is deposited onto the latent image formed on the photosensitive drum 1 to form the toner image. The toner image developed on the photosensitive drum 1 is transferred onto the sheet material S, and thereafter the toner which remains on the photosensitive drum 1 surface is removed by the cleaning means 6 and is accommodated in the residual toner container 30.

0056Here, when the toner in the toner container 41 is consumed up, the user exchanges process cartridge P, by which the user can carry out the printing again.

0057As shown in <figref idref="f0006">Figure 8</figref>, the one-end portion of the process cartridge P supports a coupling member 47 for receiving the driving force from the drum coupling member 25 of the main assembly side rotatably. It also supports a coupling member 45 for receiving the driving force from the development coupling member 26 rotatably.

0058The coupling member 47 is provided at the end of the photosensitive drum 1, and the photosensitive drum 1 is rotated by the driving force received by the coupling member 47 from the main assembly. The driving force received by the coupling member 45 is transmitted to the developing roller 40 and the toner supplying roller 43 through an unshown intermediate gear to rotate them.

0059The outer periphery of the coupling member 45 is covered by a cylindrical rib and constitutes an engaging portion 71a. The engaging portion 71a is provided on a side cover 71 fixed to the outside of the toner container 41. The coupling member 45 is rotatable relative to the engaging portion 71a. As shown in <figref idref="f0007">Figure 9</figref>, an engaging portion 70a is provided on the opposite side from the engaging portion 71a. This engaging portion 70a is similarly provided on a side cover 70. These engaging portions 71a, 70a are provided on the developing unit 4.

0060The residual toner container 30 is provided with hole portions 30a, 30b supporting the engaging portions 71a, 70a. The hole portions 30a, 30b provided in the residual toner container 30 engage with the engaging portions 71a, 70a provided in the developing unit 4, by which the photosensitive member unit 8 and the developing unit 4 connect with each other.

0061Here, the engaging portions 71a, 70a are movable (rotatable) relative to the hole portions 30a, 30b respectively, and therefore, the developing unit 4 can be moved relative to the photosensitive member unit 8. That is, the developing roller 40 is movable relative to the photosensitive drum 1.

0062As shown in <figref idref="f0006 f0007">Figure 7-Figure 9</figref>, between the photosensitive member unit 8 and the developing unit 4, a spring 9 as an urging member is provided. The spring 9 presses the developing roller 40 with the predetermined pressure to the photosensitive drum 1. When the developing unit 4 moves in the direction of separating the developing roller 40 from the photosensitive drum 1 relative to the photosensitive member unit 8, it moves against an urging force of the spring 9.

0063As shown in <figref idref="f0006">Figure 8</figref>, the outer periphery of the coupling member 47 is covered by the cylindrical rib to form a portion-to-be-guided 30c. As shown in <figref idref="f0007">Figure 9</figref>, a portion-to-be-guided 30d in the form of a cylindrical projection is provided on the opposite side of the portion-to-be-guided 30c with respect to the longitudinal direction. As shown in <figref idref="f0006">Figure 8</figref>, a portion-to-be-guided 30e is provided above the portion-to-be-guided 30c, and as shown in <figref idref="f0007">Figure 9</figref>, a portion-to-be-guided 30f is provided above the portion-to-be-guided 30d. The portions-to-be-guided 30c, 30d, 30e, 30f has the function of the guide for the mounting, into the drawer member 13, of the process cartridge P, and have a function of positioning the process cartridge P in the drawer member 13. The details thereof will be described hereinafter.

0064As shown in <figref idref="f0006">Figure 8</figref>, an upper portion of one of the lateral sides of the photosensitive member unit, 8 is provided with an outwardly projecting force receiving portion 30g with respect to an axial direction of the photosensitive drum 1. The force receiving portion 30g receives the force from the contacting and spacing member 42 provided in the drawer member 13 to space the photosensitive drum 1 from the transfer belt 11. The details thereof will be described hereinafter. As shown in <figref idref="f0007">Figure 9</figref>, furthermore, an upper portion of the other side surface of the photosensitive member unit 8 is provided with a force receiving portion 30h. The force receiving portions 30g, 30h receive a force from the urging members 65, 66 as will be described hereinafter to position the process cartridge P in the drawer member 13.

0065As shown in <figref idref="f0006">Figure 8</figref>, an outwardly projecting force receiving portion, 71b with respect to the axial direction of the developing roller 40 is provided above the side cover 71 of the developing unit 4. The force receiving portion 71b receives the force from the contacting and spacing member 42 to space the developing roller 40 from the photosensitive drum 1. The details thereof will be described hereinafter.

<Mounting of process cartridge to drawer member>

0066Referring to <figref idref="f0007 f0009">Figure 9 - Figure 11</figref>, the description will be made as to the mounting of process cartridges P (Py, Pm, Pc, Pk) to the drawer member 13. The <figref idref="f0007">figs 9</figref> and <figref idref="f0008">10</figref> are the perspective views illustrating the state that the process cartridge according to Embodiment 1 of the present invention is mounted to the drawer member. The <figref idref="f0007">Figure 9</figref> and <figref idref="f0008">Figure 10(a)</figref> show the mounting process of the process cartridge and are views, as seen from different directions. In <figref idref="f0008">Figure 10 (b)</figref>, all the process cartridges are mounted. <figref idref="f0009">Figure 11</figref> is a schematic view showing the state that the process cartridge is mounted to the drawer member. <figref idref="f0009">Figure 11 (a)</figref> is a side view, and <figref idref="f0009">Figure 11 (b)</figref> is a schematic longitudinal sectional view.

0067The process cartridges Py, Pm, Pc, Pk are mounted into the four mounting portions 13f (<figref idref="f0004">Figure 5</figref>) provided in the drawer member 13, respectively. The user mounts the process cartridge P in a direction of the arrow C which is substantially the direction of gravity.

0068In mounting the process cartridge P, first, the user moves it, so that the portions-to-be-guided 30c, 30d provided at the opposite ends of the process cartridge P are guided by the guide portions 13h, 13j of the drawer member 13. Then, the user moves it, so that the portions-to-be-guided 30e, 30f are guided by the guides 13i, 13k. By this, the process cartridge P is mounted to the inside of the drawer member 13, while being guided by the guide portions 13h, 13i, 13j and 13k.

0069In the process in which the process cartridge P is mounted to the drawer member 13, the force receiving portion 30g provided on the photosensitive member unit 8 abuts to the first projection (force applying portion) 42b provided on the contacting and spacing member 42. The force receiving portion 71b provided on the side cover 71 of the developing unit 4 abuts to the second projection (force applying portion) 42c.

0070The force receiving portion 30g provided on the photosensitive member unit 8 abuts to the first projection 42b, by which the process cartridge P is held in a position higher than the image forming position. As shown in <figref idref="f0002">Figure 2</figref>, that is, the surface of the photosensitive drum 1 is held in the (spacing) position higher than the surface (recording material conveying surface) of the transfer belt 11.

0071Here, the contacting and spacing member 42 is provided only at one-end portion of the drawer member 13. The force receiving portion 30g for receiving the force from the first projection 42b of the contacting and spacing member 42 is also provided only at the one side of the photosensitive member unit 8. However, the portion-to-be-guided 30d provided at the other end portion of the process cartridge P is provided in the outside of the widthwise end of the transfer belt 11, and therefore, the surface of the photosensitive drum 1 can be separated from the surface of the transfer belt 11. That is, as for the process cartridge P, the force receiving portion 30g receives the force from first projection 42b in the one-end portion to rise. On the other hand, the state that the portion-to-be-guided 30d is in contact to a positioning portion 13j1 of the drawer member 13 is maintained in the other end portion. For this reason, the process cartridge P is oblique relative to the transfer belt 11. However, as has been described hereinbefore, the portion-to-be-guided 30d is provided to the outside of the widthwise end of the transfer belt 11, and therefore, the surface of the photosensitive drum 1 is spaced from the surface of the transfer belt 11.

0072By the force receiving portion 71b provided on the developing unit 4 contacting to the second projection 42c provided on the contacting and spacing member 42, the surface of the developing roller 40 is spaced from the surface of the photosensitive drum 1. Referring mainly to <figref idref="f0009">Figure 11</figref>, the description will be made.

0073The second projection 42c provided on the contacting and spacing member 42 is higher than the first projection 42b. On the other hand, the force receiving portion 30g provided on the photosensitive member unit 8 and the force receiving portion 71b provided on the developing unit are substantially at the same level in the state of not receiving an external force. Therefore, the force receiving portion 71b abutted to the second projection 42c receives the weight of the developing unit 4 to space the surface of the developing roller 40 from the surface of the photosensitive drum 1 against the force of the urging member 9. That is, by the force receiving portion 71b receiving the force, the engaging portions 71a, 70a provided on the developing unit 4 rotates about the hole portions 30a, 30b provided in the photosensitive member unit 8, respectively.

0074At this time, the contacting and spacing member 42 is in such a position that the first projection 42b contacts to the force receiving portion 30g, and the second projection 42c contacts to the force receiving portion 71b. At this time, the surface of the developing roller 40 can be placed in the position spaced from the surface of the photosensitive drum 1. This position is a spacing position, wherein the contacting and spacing member 42 can isolate the photosensitive drum 1 from the transfer belt 11, and can space the developing roller 40 from the photosensitive drum 1.

0075In the case where the drawer member 13 is in the state of being drawn from the main assembly, that is, inn the case where the drawer member 13 is positioned in the outside of the main assembly (outside position), the contacting and spacing member 42 is placed in the spacing position. As shown in <figref idref="f0009">Figure 11</figref>, for this reason, when the process cartridge P is mounted to the drawer member 13, the surface of the developing roller 40 is spaced from the surface of the photosensitive drum 1 together with the mounting operation. Therefore, in mounting the process cartridge P to the drawer member 13 it can be avoided that the surface of the photosensitive drum 1 and the surface of the developing roller 40 are rubbed with each other by the impact at the time of the mounting, and these surfaces are damaged.

0076As has been described in the foregoing, in mounting the process cartridge P to the drawer member 13, the state that the surface of the developing roller 40 is spaced from the surface of the photosensitive drum 1 is maintained. In addition, the state that the surface of the photosensitive drum 1 is spaced from the surface of the transfer belt 11 is maintained.

<Mounting of drawer unit into main assembly>

0077Referring to <figref idref="f0010 f0013">Figure 12-Figure 15</figref> the description will be made as to the mounting operation of the drawer unit U1 into the main assembly. <figref idref="f0010">Figure 12</figref> is a perspective view illustrating the state that the drawer unit according to Embodiment 1 of the present invention is mounted to the inside of the main assembly. <figref idref="f0011">Figure 13</figref> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment 1 of the present invention is mounted to the inside of the main assembly. <figref idref="f0012">Figure 14</figref> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment 1 of the present invention is mounted to the inside of the main assembly, and the door is open. <figref idref="f0011">Figures 13</figref> and <figref idref="f0012">14</figref> include the enlarged cross-sectional views of the schematic sectional views of the whole device and the neighborhood of the one photosensitive drum. <figref idref="f0013">Figure 15</figref> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment 1 of the present invention is mounted to the inside of the main assembly, and the door closes. <figref idref="f0013">Figure 15</figref>, the state that the image forming operation is not carried out is shown.

0078As shown in <figref idref="f0010">Figure 12</figref>, the drawer unit U1 is mounted in a direction of arrow E while the portions-to-be-guided 13a, 13b, 13c, and 13d (<figref idref="f0004">Figures 5</figref>, <figref idref="f0005">6</figref>) of the drawer member 13 is guided by the guide portions 14R and 14L of the main assembly (<figref idref="f0003">Figures 3, 4</figref>).

0079During the mounting operation of the drawer unit U1 (drawer member 13), the state that the surface of the photosensitive drum 1 and a recording material conveying surface 11a of the transfer belt 11 are spaced from each other are maintained. That is, a gap g is provided between the surface of the photosensitive drum 1 and the recording material conveying surface 11a of the transfer belt 11. Therefore, the drawer unit U1 can be mounted to the inside of the main assembly without the rubbing between the surface of the photosensitive drum 1 and the surface of the transfer belt 11. During the mounting operation, the drawer unit U1 is moved in substantially parallel with the recording material conveying surface 11a of the transfer belt 11.

0080As has been described hereinbefore, during the mounting operation of the drawer unit U1, the separation member 14 is placed in the spacing position, the state of spacing the surface of the photosensitive drum 1 and the developing roller 40 from each other is maintained. That is, a gap h is provided between them. Therefore, in mounting the drawer unit U1 which carries the process cartridge P to the inside of the main assembly, the damage due to the contact between the surface of the photosensitive drum 1 and the surface of the developing roller 40 by the impact at the time of the mounting or the like is suppressed.

0081When the drawer unit U1 is mounted to the inside of the main assembly, the rack portion 42a (<figref idref="f0008">Figure 10</figref>) provided on the contacting and spacing member 42 and the driving gear 46 of the main assembly (<figref idref="f0003">Figure 4</figref>) engage with each other. By this, the driving force is transmittable to the rack portion 42a from the driving gear 46.

0082As shown in <figref idref="f0012">Figure 14</figref>, in the state that the drawer unit U1 is completely inserted into the main assembly, and the door 10 is open, the surface of the photosensitive drum 1 and the recording material conveying surface 11a of the transfer belt 11 are still spaced from each other. The surfaces of the photosensitive drum 1 and the developing roller 40 are spaced from each other similarly.

0083In the state of <figref idref="f0013">Figure 15</figref>, the door is closed. By the closing operation of the door 10, the drum coupling member 25 and the development coupling member 26 (<figref idref="f0003">Figure 4</figref>) enter the opening portion 13m and 131 of the opening portion (<figref idref="f0004">Figure 5</figref>) provided in the drawer member 13, respectively. However, the process cartridge P is not placed in a regular position (the operative position for the image formation) as yet. Therefore, the drum coupling member 25 and the development coupling member 26 are not in engagement with the coupling members 47 and 45 (<figref idref="f0006">Figure 8</figref>).

0084Also in the state where the door 10 is closed, when the image forming operation is not carried out, the spaced state is maintained between the surface of the photosensitive drum 1 and the recording material conveying surface 11a of the transfer belt 11, and between the surface of the photosensitive drum 1 and the surface of the developing roller 40. That is, the contacting and spacing member 42 is placed in the spacing position.

0085In such a state, apparatus is maintained until the instruction of the image forming operation is produced from the main assembly.

<Operations at the time of image forming operation >

0086Referring to <figref idref="f0013 f0018">Figure 16-Figure 21</figref> the description will be made as to the operation of each part at the time of the image forming operation. <figref idref="f0013">Figure 16</figref> is a perspective view illustrating the state immediately after the image formation instruction in the drawer unit according to Embodiment 1 of the present invention. <figref idref="f0014">Figure 17</figref> is a schematic sectional view illustrating the state in which the drawer unit according to Embodiment 1 of the present invention is mounted to the inside of the main assembly, and in which it is of partway of shifting to the image forming operation. <figref idref="f0014">Figure 17</figref> includes a schematic sectional view of the neighborhood of the drawer unit and the transfer belt and an enlarged cross-sectional view of the neighborhood of the one photosensitive drum. <figref idref="f0015">Figure 18</figref> is a perspective view illustrating the state of the partway of shifting to the image forming operation in the drawer unit according to Embodiment 1 of the present invention. <figref idref="f0016">Figure 19</figref> is a schematic sectional view illustrating the state of the partway of shifting to the image forming operation in the image forming apparatus according to Embodiment 1 of the present invention. <figref idref="f0016">Figure 19</figref> includes a schematic sectional view of the whole device and an enlarged cross-sectional view of the neighborhood of the one photosensitive drum. <figref idref="f0017">Figure 20</figref> is a perspective view illustrating the state in the course of shifting to the image forming operation in the drawer unit according to Embodiment 1 of the present invention. <figref idref="f0018">Figure 21</figref> is a schematic sectional view illustrating the state that the image forming operation is capable in the image forming apparatus according to Embodiment 1 of the present invention. <figref idref="f0018">Figure 21</figref> includes an enlarged cross-sectional view of a schematic sectional view of the whole device and the neighborhood of one photosensitive drum.

0087The instruction of the image formation is produced, the driving gear 46 connected operatively with a motor (unshown) provided in the main assembly is rotated in a direction of arrow F in <figref idref="f0013">Figure 16</figref>. By this, the contacting and spacing member 42 is moved in the direction of arrow G in the Figure by the rack portion 42a engaged with the driving gear 46. When the contacting and spacing member 42 move to the position shown in <figref idref="f0013">Figure 16</figref>, the force receiving portion 30g provided on the photosensitive member unit 8 separates from the first projection 42b of the contacting and spacing member 42. However, the force receiving portion 71b provided in the developing unit 4 is still placed on the second projection 42c. Since the second projection 42c is longer than the first projection 42b, such a mechanism is established in the movement direction of the contacting and spacing member 42.

0088<figref idref="f0014">Figure 17</figref> shows a positional relation among the drawer member 13, the process cartridge P, and the transfer belt 11 in the state shown in <figref idref="f0013">Figure 16</figref>. As has been described hereinbefore, the force receiving portion 30g separates from the first projection 42b by a moving operation of the contacting and spacing member 42, by which the surface of the photosensitive drum 1 is contacted to the surface of the transfer belt 11. On the other hand, the force receiving portion 71b is maintained in the state of receiving the force from the second projection 42c, and therefore, the developing roller 40 is spaced from the surface of the photosensitive drum 1. Here, the space is maintained between the surface of the photosensitive drum 1 and the surface of the developing roller 40, and therefore, the contacting and spacing member 42 takes the spacing position.

0089As shown in <figref idref="f0015">Figure 18</figref>, thereafter, the urging members 65, 66 provided in the main assembly side are driven with the unshown driving source and moves in a direction of arrow H. The urging members 65, 66 abut to the force receiving portions 30g, 30h provided on the process cartridge P and apply the force to it. By this, the portion-to-be-guided 30c (<figref idref="f0006">Figure 8</figref>) of the process cartridge P abuts to the positioning portion 13h1 (<figref idref="f0007">Figure 9</figref>) provided on the drawer member 13. The portion-to-be-guided 30d (<figref idref="f0007">Figure 9</figref>) abuts to the positioning portion 13j1 (<figref idref="f0008">Figure 10</figref>). Furthermore, the portions-to-be-guided 30e and 30f (<figref idref="f0006">Figures 8</figref>, <figref idref="f0007">9</figref>) engage with the guide portions 13i and 13k (<figref idref="f0007">Figures 9</figref>, <figref idref="f0008">10</figref>), and the process cartridge P is positioned in the drawer member 13.

0090As has been described in the foregoing, by the function of the urging members 65, 66, the process cartridge P is positioned in the main assembly.

0091<figref idref="f0016">Figure 19</figref> shows the inside a main assembly in the state shown in <figref idref="f0015">Figure 18</figref>. In the process cartridge P in this state, the surface of the developing roller 40 is spaced from the surface of the photosensitive drum 1. The surface of the photosensitive drum 1 is kept spaced from the surface of the transfer belt 11. That is, the position of the contacting and spacing member 42 at this time corresponds to the spacing position.

0092As shown in <figref idref="f0017">Figure 20</figref>, thereafter, in order to contact the developing roller 40 and the photosensitive drum 1 relative to each other, the driving gear 46 further rotates and moves the contacting and spacing member 42 in a direction of arrow G. By this, the force receiving portion 71b provided on the developing unit 4 separates from the second projection 42c of the contacting and spacing member 42 and does not receive the force from the second projection 42c. Therefore, the surface of the developing roller 40 and the surface of the photosensitive drum 1 contact to each other by the urging force of the spring 9 provided between the developing unit 4 and the photosensitive member unit 8. By this, as for the image forming apparatus 100, the image formation is enabled. This position is a contacting position, wherein the contacting and spacing member 42 contacts the developing roller 40 to the photosensitive drum 1 to enable the image formation. The image forming operation is as has been described hereinbefore. <figref idref="f0018">Figure 21</figref> shows the inside of the main assembly at the time of being in the state that the image forming operation is capable.

0093When the image formation finishes, the driving gear 46 is rotated in the direction opposite the direction of arrow F shown in <figref idref="f0013">Figure 16</figref> to move the contacting and spacing member 42 in the direction of arrow I in <figref idref="f0017">Figure 20</figref>. By this, the contacting and spacing member 42 is moved to the spacing position, and spaces the surface of the developing roller 40 from the surface of the photosensitive drum 1 (<figref idref="f0015">Figures 18</figref>, <figref idref="f0016">19</figref>).

0094Thereafter, the urging members 65, 66 carry out in movement in the direction opposite the above described pressing direction, and the contacting and spacing member 42 further moves in a direction of arrow I. By this, the surface of the photosensitive drum 1 is spaced from the surface of the transfer belt 11. In this state, the apparatus waits for the instruction of the next image formation. Or, in the case where the drawer member 13 is drawn, the state is maintained in which the surface of the photosensitive drum 1 and the surface (recording material conveying surface 11a) of the transfer belt 11 are spaced from each other and the surface of the photosensitive drum 1 and the surface of the developing roller 40 are spaced from each other. That is, the contacting and spacing member 42 is placed in the spacing position. Therefore, when the drawer member 13 which carries the process cartridge P is drawn from the main assembly, the damage due to the contact between the surface of the photosensitive drum 1 and the surface of the developing roller 40 by the impact at the time of the movement or the like is suppressed.

0095As has been described in the foregoing, according to the image forming apparatus 100 of this embodiment, the contacting and spacing member is movable between the spacing position and the contacting position And, by the movement of the contact member 42, the developing roller 40 moves timely to the position of spacing from the photosensitive drum 1 or the position of contacting to the photosensitive drum 1. By this, the state of the developing roller 40 not contacting to the photosensitive drum 1 can be established, when the image forming operation is not carried out, namely, during drawing the drawing unit U1 (drawer member 13) outwardly, and so on. Therefore, the deteriorations of various members can be suppressed, and the service lives can be extended.

0096In addition, the image forming apparatus 100 according to this embodiment employs a structure in which the drawer member 13 is provided with the contacting and spacing member 42. Therefore, the structure for advancing the contacting and spacing member from the main assembly side of the apparatus into the drawer member is not necessitated unlike in the conventional example in which the contacting and spacing member for spacing the developing roller from the photosensitive drum is provided in the main assembly side of the apparatus. In other words, no space is required to move the contacting and spacing member from the main assembly side of the apparatus to the position of the cartridge in the drawer member, and therefore, the main assembly of the apparatus can be downsized.

0097It would be considered that the contacting and spacing member is fixed to the main assembly side of the apparatus, and a force receiving portion of the drawer member provided in the cartridge receives a force from the contacting and spacing member by a pushing-in operation and a drawing operation to contact and space the developing roller relative to the photosensitive drum.

0098However, even when such a structure is employed, it is necessary to project the force receiving portion out of the drawer member in order to make the force receiving portion of the cartridge contactable to the contacting and spacing member. Therefore, the apparatus is not downsized enough. According to this embodiment, however, the contacting and spacing member 42 is provided in the drawer member 13, and therefore, it is unnecessary to project the force receiving portion 71b too much, and the process cartridge P can be downsized.

0099Even when such structures are employed, the cartridge has to be mounted in the state that the force receiving portion of the cartridge is retracted from the contacting and spacing member, in order to contact the force receiving portion of the cartridge to the contacting and spacing member at the desired timing. And, the result is that the structure or mechanism is required to move the entire drawer member to the position where the force receiving portion of the cartridge contacts to the contacting and spacing member. According to this embodiment, however, the contacting and spacing member 42 is provided in the drawer member 13, and therefore, the structure of the main assembly of the apparatus can be simplified and downsized.

0100In this embodiment, as for the example of the transfer belt 11, the sheet material S which is the transfer member is fed to the surface of the photosensitive drum 1, and the developer image on the photosensitive drum 1 is directly transferred onto the sheet material S. However, the present invention is applicable also to the image forming apparatus, wherein the transfer belt receives the developer image formed on the photosensitive drum and, finally the image is transferred onto the recording material (sheet material) (intermediary transfer belt type).

0101In this embodiment, the contacting and spacing member 42 is provided only at the one-end portion of the drawer member 13. However, a contacting and spacing member may also be provided like the other end portion of the drawer member 13. In this case, the force receiving portion for receiving the force from the contacting and spacing member is also provided in the other end portion. If the contacting and spacing member is provided at the respective sides, the shafts of the photosensitive drum and the developing roller in the process cartridge do not incline during the movement thereof. Therefore, the spaced state between the photosensitive drum and the transfer belt and the spaced state between the photosensitive drum and the developing roller can further be stabilized.

(Embodiment 2)

0102<figref idref="f0019 f0031">Figure 22-Figure 36</figref> illustrates the various parts by Embodiment 2 of the present invention. In Embodiment 1, the process cartridge P which contains the photosensitive member unit 8 which includes the photosensitive drum 1 and the developing unit 4 which includes the developing roller 40 integrally is mounted to the drawer member 13. In this embodiment, a photosensitive member unit which includes the photosensitive drum 1 and the developing unit which includes the developing roller 40 are mounted individually to a drawer member 63. The like reference numerals as in the foregoing embodiment are assigned to the elements having the corresponding functions.

<Developing cartridge>

0103Referring to <figref idref="f0019">Figure 22</figref>, the description will be made as to the developing cartridge which is the developing unit according to Embodiment 2 of the present invention. <figref idref="f0019">Figure 22</figref> is a perspective view of the developing cartridge according to Embodiment 2 of the present invention. In <figref idref="f0019">Figure 22</figref>, they are perspective views, as seen from the different directions ((a) and (b)).

0104A developing cartridge 60 according to this embodiment comprises the developing roller 40, a toner supplying roller (unshown), a developing blade (unshown), and a toner container 41 which contains the toner which is the developer used for the image formation. In the image forming apparatus according to this embodiment, the four developing cartridge s 60 which contain the toner of the different color are used. The reference numerals for these cartridges are 60y, 60m, 60c, and 60k but the reference numerals maybe simply "60" if no confusion arises. Here, y means the yellow, m means the magenta, c means the cyan, and k means the black.

0105As shown in <figref idref="f0019">Figure 22</figref>, the one-end portion of the developing cartridge 60 rotatably supports the coupling member 45 for receiving the driving force from the development coupling member 26 of the main assembly side. The driving force received by the coupling member 45 is transmitted to the developing roller 40, the toner supplying roller, and so on through the unshown intermediate gear.

0106The upper portion of the side cover, 61 of one side of the developing cartridge 60 is provided with an outwardly projecting force receiving portion 61a with respect to the axial direction which is the developing roller 40. This force receiving portion 61a receives the force from the contacting and spacing member 42 (<figref idref="f0021">Figure 24</figref>) to space the developing roller 40 from the photosensitive drum 1. The details thereof will be described hereinafter. Furthermore, the upper portion of a side cover 62 of the another side of the developing cartridge 60 is provided with a force receiving portion 62a. The force receiving portions 61a, 62a is pressed by the urging members provided in the main assembly to position the developing cartridge 60 relative to the drawer member 63. The details thereof will be described hereinafter.

0107Adjacent to the force receiving portions, 61a, 62a, a portions to be positioned 61b, 62b are provided, and they outwardly project with respect to the axial direction which is the developing roller 40. The details thereof will be described hereinafter.

<Photosensitive member cartridge>

0108Referring to <figref idref="f0020">Figure 23</figref> the description will be made as to the photosensitive member cartridge which is the photosensitive member unit according to Embodiment 2 of the present invention. <figref idref="f0020">Figure 23</figref> is a perspective view of the photosensitive member cartridge according to Embodiment 2 of the present invention. In <figref idref="f0020">Figure 23</figref>, they are the perspective views, as seen from the different directions ((a) and (b)).

0109A photosensitive member cartridge 50 according to this embodiment comprises the photosensitive drum 1, the charging means 2, the cleaning means (unshown), and a residual toner container 31 for containing the toner removed by the cleaning means. As for the image forming apparatus according to this embodiment, the four photosensitive member cartridge s 50 which contain the toner of the different color are used. The reference numerals for these cartridges are 50y, 50m, 50c, and 50k but the reference numerals maybe simply 50 if no confusion arises, although y means yellow, m means magenta, c means cyan, and k means black.

0110As shown in <figref idref="f0020">Figure 23</figref>, one-end portion of the photosensitive member cartridge 50 supports the coupling member 47 for receiving the driving force from the drum coupling member 25 of the main assembly side rotatably. The coupling member 47 is provided at the end of the photosensitive drum 1, and the photosensitive drum 1 rotates by the driving force received by the coupling member 47 from the main assembly side.

0111An outer periphery of the coupling member 47 is covered by the cylindrical rib to constitute a portion-to-be-guided 31a. On the opposite side of the portion-to-be-guided 31a, a portion-to-be-guided 31b which is provided with the cylindrical projection is provided. Above the portion-to-be-guided 31a, a portion-to-be-guided 31c is provided, and above the portion-to-be-guided 31b, a portion-to-be-guided 31d is provided. The portions-to-be-guided 31a, 31b, 31c, 31d has the guiding function, when the photosensitive member cartridge 50 is mounted into the drawer member 63 and when it is positioned in the drawer member 63. The details thereof will be described hereinafter.

0112One of the upper portions of the ends of the photosensitive member cartridge, 50 is provided with a force receiving portion 31e outwardly projected with respect to the axial direction from the photosensitive drum 1. The force receiving portion 31e receives the force from the contacting and spacing member 42 (<figref idref="f0021">Figure 24</figref>) provided in the drawer member 63 to space the photosensitive drum 1 from the transfer belt 11. The details thereof will be described hereinafter. Furthermore, the other end of the photosensitive member cartridge 50 is provided with a force receiving portion 31f. The force receiving portions 31e, 31f is pressed by the urging members provided in the main assembly, to position the photosensitive member cartridge 50 relative to the drawer member 63. The details thereof will be described hereinafter.

<Drawer member (supporting member)>

0113Referring to <figref idref="f0021">Figures 24 and 25</figref> the description will be made as to the drawer member 63 according to Embodiment 2 of the present invention. The <figref idref="f0021">figs 24 and 25</figref> are the perspective views of the drawer unit in the image forming apparatus according to Embodiment 2 of the present invention. The <figref idref="f0021">Figure 24 and Figure 25</figref> are the perspective views, as seen from the different directions.

0114The drawer unit U2 according to this embodiment is different from Embodiment 1 in that the drawer member 63 is provided with the positioning portions 63a, 63b in order to position the developing cartridge 60 in the drawer member 63.

0115The developing cartridge 60 is positioned in the drawer member 63 by the portions to be positioned 61b and 62b (<figref idref="f0019">Figure 22</figref>) engaging with the positioning portions 63a, 63b provided in the drawer member 63.

0116Similarly to Embodiment 1, the drawer member 63 is provided with the contacting and spacing member 42. Since the structure of the contacting and spacing member 42 is similar to Embodiment 1, the description is omitted for the sake of simplicity. In addition, similarly to Embodiment 1, the drawer unit U2 comprises the drawer member 63 and the contacting and spacing member 42.

<Mounting of photosensitive member cartridge and developing cartridge to drawer member>

0117Referring to <figref idref="f0022">Figures 26</figref> and <figref idref="f0023">27</figref> the description will be made as to the mounting of the developing cartridge s 60 (60y, 60m, 60c, 60k) and the photosensitive member cartridges 50 (50y, 50m, 50c, 50k) to the drawer member 63. The <figref idref="f0022">figs 26</figref> and <figref idref="f0023">27</figref> are the perspective views illustrating the state of mounting the photosensitive member cartridge and the developing cartridge according to Embodiment 2 of the present invention to the drawer member. The <figref idref="f0022">figs 26</figref> and <figref idref="f0023">27</figref> illustrate the state of the process of the mounting of the cartridge and are views, as seen from the different directions.

0118In this embodiment, the photosensitive member cartridge 50 and the developing cartridge 60 are mounted individually into the drawer member 63. In the case of mounting them to the drawer member 63, the photosensitive member cartridge 50 is mounted, and thereafter the developing cartridge 60 is mounted.

0119In the case of mounting the photosensitive member cartridge 50, it is mounted by the user while the portions-to-be-guided 31a, 31b provided at the opposite ends of the photosensitive member cartridge 50 are guided to the guide portions 63c, 63d of the drawer member 63. Then, it is mounted while the portions-to-be-guided 31c, 31d are guided by the guide portions 63e, 63f. By this, the photosensitive member cartridge 50 is mounted to the inside of the drawer member 63.

0120In the case of mounting the developing cartridge 60, the user mounts the developing cartridge 60, so that the portions to be positioned 61b, 62b of the developing cartridge 60 aligns with the positioning portions 63a, 63b provided in the drawer member 63. However, the portions to be positioned 61b, 62b are not contacted to the positioning portions 63a, 63b at the time mounting.

0121In the process in which the photosensitive member cartridge 50 is mounted to the drawer member 63, the force receiving portion 31e provided on the photosensitive member cartridge 50 contacts to the first projection (force applying portion) 42b (<figref idref="f0022">Figure 26</figref>) provided on the contacting and spacing member 42. The force receiving portion 61a provided on the side cover 71 of the developing cartridge 60 contacts to the second projection (force applying portion) 42c (<figref idref="f0022">Figure 26</figref>).

0122By the force receiving portion 31e provided on the photosensitive member cartridge 50 contacting to the first projection 42b, the photosensitive member cartridge 50 is held at the position higher than the image forming position. That is, the surface of the photosensitive drum 1 is held at the position (spaced position) higher than the surface (recording material conveying surface 11a) of the transfer belt 11.

0123By the force receiving portion 61a provided on the developing cartridge 60 contacting to the second projection 42c provided on the contacting and spacing member 42, the surface of the developing roller 40 is spaced from the surface of the photosensitive drum 1. As to this, the description will be made referring to <figref idref="f0024">Figure 28. Figure 28</figref> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment 2 of the present invention is mounted into the main assembly. In <figref idref="f0024">Figure 28</figref>, a schematic sectional view of the whole device and a schematic enlarged cross-sectional view of a photosensitive drum neighborhood are shown.

0124The second projection 42c provided on the contacting and spacing member 42 is disposed at the position higher than the first projection 42b. On the other hand, the force receiving portion 31e provided in the photosensitive member cartridge 50 and the force receiving portion 61a provided in the developing cartridge 60 are substantially at the same heights in the state of not receiving the external force. By this, the developing cartridge 60 is held at the position higher than the photosensitive member cartridge 50. Therefore, the surface of the developing roller 40 is separated from the surface of the photosensitive drum 1.

0125Here, the contacting and spacing member 42 is provided only at the one-end portion of the drawer member 63. The force receiving portion 61a for receiving the force from the second projection 42c of the contacting and spacing member 42 is also provided only on the one side of the developing cartridge 60. However, since the portion to be positioned, 62b provided at the other end portion of the developing cartridge, 60 is outwardly provided beyond the end with respect to the longitudinal direction of the photosensitive drum 1, the surface of the developing roller 40, can be separated from the surface of the photosensitive drum 1. That is, the force receiving portion 61a receives the force from the second projection 42c, so that the developing cartridge 60 rises at the one-end portion. On the other hand, in the other end portion, the portion to be positioned 62b is in contact to a positioning portion 63b of the drawer member 63. For this reason, the developing cartridge 60 is oblique relative to the photosensitive drum 1. However, as has been described hereinbefore, since the portion to be positioned 62b is outwardly provided beyond the longitudinal end of the photosensitive drum 1, the surface of the developing roller 40 is spaced from the surface of the photosensitive drum 1.

0126In this manner, when the photosensitive member cartridge 50 and the developing cartridge 60 are mounted, the contacting and spacing member 42 is in such a position that the first projection 42b contacts to the force receiving portion 31e, and the second projection 42c contacts to the force receiving portion 61a. At this time, the surface of the photosensitive drum 1 can be placed in the position spaced from the surface of the transfer belt 11. The surface of the developing roller 40 can be placed in the position spaced from the surface of the photosensitive drum 1. Similarly to Embodiment 1, such a position that the contacting and spacing member 42 spaces the developing roller 40 from the photosensitive drum 1, is a spacing position.

0127In this manner, in the process in which the developing cartridge 60 is mounted to the drawer member 63, in the state that the surface of the developing roller 40 is spaced from the surface of the photosensitive drum 1, the developing cartridge 60 is mounted. Therefore, in mounting the developing cartridge 60 to the drawer member 63 the surface damage due to the rubbing between the surface of the photosensitive drum 1 and the surface of the developing roller 40 by the impact at the time of the mounting can be suppressed.

0128As has been described in the foregoing, the photosensitive member cartridge 50 and the developing cartridge 60 are mounted to the drawer member 63 while spacing is established between the surface of the developing roller 40 and the surface of the photosensitive drum 1 and between the surface of the photosensitive drum 1 and the surface of the transfer belt 11.

<Mounting of drawer unit into main assembly>

0129Referring to <figref idref="f0025 f0027">Figure 29-Figure 31</figref>, the description will be made as to the mounting operation of the drawer unit U2 into the main assembly. <figref idref="f0025">Figure 29</figref> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment 2 of the present invention is mounted to the inside of the main assembly. <figref idref="f0026">Figure 30</figref> is a schematic sectional view illustrating the state which the drawer unit according to Embodiment 2 of the present invention is mounted to the inside of the main assembly, and the door opens. <figref idref="f0025">Figures 29</figref> and <figref idref="f0026">30</figref> include a schematic sectional view of the whole device and a schematic enlarged cross-sectional view of the neighborhood of one photosensitive drum are shown. <figref idref="f0027">Figure 31</figref> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment 2 of the present invention is mounted to the inside of the main assembly, and the door closes. In <figref idref="f0027">Figure 31</figref>, the image forming operation is not carried out.

0130As shown in <figref idref="f0025">Figure 29</figref>, the drawer unit U2 (drawer member 63) is mounted to the inside of the main assembly in a direction of the arrow D1. During the mounting operation of the drawer unit U2, the surface of the photosensitive drum 1 and the recording material conveying surface 11a of the transfer belt 11 are spaced from each other. That is, a gap g is provided between the surface of the photosensitive drum 1 and the recording material conveying surface 11a of the transfer belt 11. Therefore, the drawer unit U2 can be mounted to the inside of the main assembly without the surface of the photosensitive drum 1 rubbing with the surface of the transfer belt 11.

0131During the mounting operation of the drawer unit U2, the contacting and spacing member 42 is placed in the spacing position, and the surfaces of the photosensitive drum 1 and the developing roller 40 is also spaced from each other. That is, the gap h is provided therebetween. Therefore, in mounting the drawer unit U2 to the inside of the main assembly, the damage due to the contact between the surface of the photosensitive drum 1 and the surface of the developing roller 40 by the impact at the time of the mounting and so on can be suppressed.

0132As shown in <figref idref="f0026">Figure 30</figref>, in the state that the drawer unit U2 is completely inserted into the main assembly, and the door 10 is open, the surface of the photosensitive drum 1 and the recording material conveying surface 11a of the transfer belt 11 are still spaced from each other. The surfaces of the photosensitive drum 1 and the developing roller 40 are also spaced from each other.

0133<figref idref="f0027">Figure 31</figref> shows the state where the door is closed. , even if the door 10 is in the closed state, when the image forming operation is not carried out, the space is kept between the surface of the photosensitive drum 1 and the recording material conveying surface 11a of the transfer belt 11 and between the surface of the photosensitive drum 1 and the surface of the developing roller 40 That is, the contacting and spacing member 42 is placed in the spacing position.

0134In the state as described above, the device waits for the instruction of the image forming operation from the main assembly.

<Operation of each part at the time of image forming operation>

0135Referring to <figref idref="f0028 f0031">Figure 32-Figure 36</figref>, the description will be made as to the operation of each part at the time of the image forming operation. <figref idref="f0028">Figure 32</figref> is a perspective view illustrating the state immediately after the image formation instruction in the drawer unit according to Embodiment 2 of the present invention. <figref idref="f0029">Figure 33</figref> is a schematic sectional view illustrating the state in the course of the drawer unit according to Embodiment 2 of the present invention being mounted to the inside of the main assembly, and shifting to the image forming operation. <figref idref="f0029">Figure 33</figref> includes a schematic sectional view of the whole device and a schematic enlarged cross-sectional view of the neighborhood of the one photosensitive drum. <figref idref="f0027">Figure 34</figref> is a schematic sectional view illustrating the state in the course of shifting to the image forming operation in the image forming apparatus according to Embodiment 2 of the present invention. <figref idref="f0030">Figure 35</figref> is a schematic sectional view illustrating the state in the course of shifting to the image forming operation in the image forming apparatus according to Embodiment 2 of the present invention. <figref idref="f0030">Figure 35</figref> includes a schematic sectional view of the whole device and a schematic enlarged cross-sectional view of the neighborhood the one photosensitive drum. <figref idref="f0031">Figure 36</figref> is a schematic sectional view illustrating the state that the image forming operation is enabled in the image forming apparatus according to Embodiment 2 of the present invention. <figref idref="f0031">Figure 36</figref> includes a schematic sectional view of the whole device and a schematic enlarged cross-sectional view of the neighborhood of the one photosensitive drum.

0136When the instruction of the image formation is produced, the driving gear 46 connected operatively with the motor (unshown) provided in the main assembly rotate in the direction of arrow F as shown in <figref idref="f0028">Figure 32</figref>,. Therefore, by the rack portion 42a in engagement with the driving gear 46, the contacting and spacing member 42 is moved in the direction of arrow G in the Figure. When the contacting and spacing member 42 moves to the position shown in <figref idref="f0028">Figure 32</figref>, the force receiving portion 31e provided on the photosensitive member cartridge 50 separates from the first projection 42b of the contacting and spacing member 42. However, the force receiving portion 61a provided on the developing cartridge 60 is still placed on the second projection 42c. Such a mechanism is established because the second projection 42c is longer than the first projection 42b with respect to the movement direction of the contacting and spacing member 42.

0137<figref idref="f0029">Figure 33</figref> shows a schematic sectional view of the entirety of the device in the state of <figref idref="f0028">Figure 32</figref>. As has been described hereinbefore, the force receiving portion 31e separates from the first projection 42b by the moving operation of a contacting and spacing member 52, by which the surface of the photosensitive drum 1 is contacted to the surface of the transfer belt 11. On the other hand, the force receiving portion 61a is still in the state of keeping receiving the force from the second projection 42c, and therefore, the developing roller 40 is spaced from the surface of the photosensitive drum 1. The surface of the photosensitive drum 1 and the surface of the developing roller 40 are spaced from each other, and position of the contacting and spacing member 42 is a spacing position.

0138As shown in <figref idref="f0027">Figure 34</figref>, thereafter, the urging members 65, 66 provided in the main assembly side are driven by the unshown driving source to move in the direction of arrow H. The urging members 65, 66 contact to the force receiving portions 31e and 31f (<figref idref="f0020">Figure 23</figref>) provided on the photosensitive member cartridge 50 to apply a force thereto. By this, the portion-to-be-guided 31a (<figref idref="f0020">Figure 23</figref>) of the photosensitive member cartridge 50 contacts to a positioning portion 63c1 (<figref idref="f0021">Figure 25</figref>) provided in the drawer member 63. The portion-to-be-guided 31b (<figref idref="f0020">Figure 23</figref>) contacts to the positioning portions 63d1 (<figref idref="f0021">Figure 24</figref>). Furthermore, the portions-to-be-guided 31c and 31d (<figref idref="f0020">Figure 23</figref>) fitting with the guide portions 63e and 63f (<figref idref="f0021">Figures 24, 25</figref>), and, and the photosensitive member cartridge 50 is positioned in the drawer member 63.

0139As has been described in the foregoing, by the function of the urging members 65, 66, the photosensitive member cartridge 50 is positioned in the main assembly.

0140Thereafter, in order to contact the developing roller 40 to the photosensitive drum 1, the driving gear 46 further rotates, and the contacting and spacing member 42 is further moved to the direction of arrow G (<figref idref="f0028">Figure 32</figref>). By this, the force receiving portion 61a provided in the developing cartridge 60 separates from the second projection 42c of the contacting and spacing member 42 and does not receive the force from a second projection 42C. By this, the developing cartridge, 60 is moves downwardly with respect to the vertical direction by the weight thereof, so that the surface of the developing roller 40 and the surface of the photosensitive drum 1, contact to each other. At this time, the portions to be positioned 61b and 62b (<figref idref="f0019">Figure 22</figref>) of the developing cartridge 60 and the positioning portions 63a and 63b (<figref idref="f0021">Figures 24, 25</figref>) provided in the drawer member 63 are not in contact yet to each other. <figref idref="f0030">Figure 35</figref> is a schematic sectional view illustrating the state at that time. In this state, as has been described hereinbefore, the surface of the developing roller 40 and the surface of the photosensitive drum 1 contact to each other. The position in which the contacting and spacing member 42 contacts the developing roller 40 to the photosensitive drum 1 is a contacting position.

0141As shown in <figref idref="f0031">Figure 36</figref>, thereafter, an urging member 67 provided in the main assembly is driven by the unshown driving source to move in a direction of arrow J. The urging members 67 are provided on the both side surfaces of the main assembly, and four pairs thereof are provided correspondingly to the developing cartridge 60.

0142The pair of urging members 67 abut to the force receiving portions 61a and 62a (<figref idref="f0019">Figure 22</figref>) provided on the developing cartridge 60 to apply a force. By this, the portions to be positioned 61b and 62b (<figref idref="f0019">Figure 22</figref>) of the developing cartridge 60 is pressed toward the positioning portions 63a and 63b (<figref idref="f0021">Figures 24, 25</figref>) provided in the drawer member 63. The surface of the developing roller 40 is pressed toward the surface of the photosensitive drum 1 as the fulcrum in the portions to be positioned 61b, 62b. The surface of the photosensitive drum 2 enters into the surface of the developing roller 40, and at the time of the amount of entrances reaches the predetermined level, the portions to be positioned 61b, 62b of the developing cartridge 60 and the positioning portions 63a, 63b provided on the drawer member 63 contact to each other.

0143As has been described in the foregoing, the developing cartridge 60 is positioned in the main assembly by the urging member 67.

0144When the positioning of the developing cartridge 60 is completed, the image formation is enabled in the image forming apparatus 100. In this state, the contacting and spacing member 42 is placed in a contacting position, wherein the developing roller 40 can be contacted to the photosensitive drum 1. As for the image forming operation, the description in Embodiment 1 applies.

0145When the image formation finishes, the urging member 67 is moved in the opposite direction (opposite direction to arrow J in <figref idref="f0031">Figure 36</figref>) to the above-described pressing direction with the unshown driving source. The driving gear 46 is rotated in the direction of arrow F shown in <figref idref="f0028">Figure 32</figref> is the opposite direction, and the contacting and spacing member 42 is moved in the direction of arrow I in <figref idref="f0028">Figure 32</figref>. By this, the contacting and spacing member 42 is moved to the spacing position, and the surface of the developing roller 40 is spaced from the surface of the photosensitive drum 1 (<figref idref="f0027">Figure 34</figref>).

0146Thereafter, the urging members 65, 66 move in the opposite direction to the above-described pressing direction, and the contacting and spacing member 42 further moves in the direction of arrow I. By this, the surface of the photosensitive drum 1 is spaced from the surface of the transfer belt 11 (<figref idref="f0027">Figure 31</figref>). In this state, the device waits for the instruction of the next image formation. Or, in the case of drawing the drawer member 63, the spacing is maintained between the surface of the photosensitive drum 1 and the surface (recording material conveying surface 11a) of the transfer belt 11, and between the surface of the photosensitive drum 1 and the surface of the developing roller 40. That is, the contacting and spacing member 42 is placed in the spacing position. Therefore, in drawing the drawer member 63 to the outside of the main assembly the damage due to the contact between the surface of the photosensitive drum 1 and the surface of the developing roller 40 by the impact at the time of the movement and so on can be suppressed. Furthermore, since this spacing can be maintained the rubbing between these surfaces can be prevented.

0147As has been described in the foregoing, according to the image forming apparatus 100 of this embodiment, the contacting and spacing member is movable between the spacing position and the contacting position And, by the movement of the contact member 42, the developing roller 40 moves timely to the position of spacing from the photosensitive drum 1 or the position of contacting to the photosensitive drum 1. By this, the state of the developing roller 40 not contacting to the photosensitive drum 1 can be established, when the image forming operation is not carried out, namely, during drawing the drawing unit U1 (drawer member 13) outwardly, and so on. Therefore, the deteriorations of various members can be suppressed, and the service lives can be extended.

0148In addition, the image forming apparatus 100 according to this embodiment employs a structure in which the drawer member 13 is provided with the contacting and spacing member 42. Therefore, the structure for advancing the contacting and spacing member from the main assembly side of the apparatus into the drawer member is not necessitated unlike in the conventional example in which the contacting and spacing member for spacing the developing roller from the photosensitive drum is provided in the main assembly side of the apparatus. In other words, no space is required to move the contacting and spacing member from the main assembly side of the apparatus to the position of the cartridge in the drawer member, and therefore, the main assembly of the apparatus can be downsized.

0149It would be considered that the contacting and spacing member is fixed to the main assembly side of the apparatus, and a force receiving portion of the drawer member provided in the cartridge receives a force from the contacting and spacing member by a pushing-in operation and a drawing operation to contact and space the developing roller relative to the photosensitive drum.

0150However, even when such a structure is employed, it is necessary to project the force receiving portion out of the drawer member in order to make the force receiving portion of the cartridge contactable to the contacting and spacing member. Therefore, the apparatus is not downsized enough. According to this embodiment, however, the contacting and spacing member 42 is provided in the drawer member 63, and therefore, it is unnecessary to project the force receiving portion 71b too much, and the developing cartridge 63 can be downsized.

0151Even when such structures are employed, the cartridge has to be mounted in the state that the force receiving portion of the cartridge is retracted from the contacting and spacing member, in order to contact the force receiving portion of the cartridge to the contacting and spacing member at the desired timing. And, the result is that the structure or mechanism is required to move the entire drawer member to the position where the force receiving portion of the cartridge contacts to the contacting and spacing member. According to this embodiment, however, the contacting and spacing member 42 is provided in the drawer member 13, and therefore, the structure of the main assembly of the apparatus can be simplified and downsized.

0152In the example of the transfer belt 11 in this embodiment, the transfer belt 11 feeds the sheet material S to the photosensitive drum 1 surface, and the developer image on the photosensitive drum 1 is directly transferred onto the sheet material S. However, the present invention is applicable to an image forming apparatus, wherein the developer image formed on the photosensitive drum is transferred, and finally it is re-transferred onto the recording material (sheet material) (intermediary transfer belt system).

0153In this embodiment, the contacting and spacing member 42 is provided only at the one-end portion of the drawer member 63. However, the contacting and spacing member maybe similarly provided also at the other end portion of the drawer member 63. However, in this case, it is preferable that the force receiving portion for receiving the force from the contacting and spacing member is also provided at the opposite ends. If the contacting and spacing members are provided on the respective sides, the shafts of the photosensitive drum and the developing roller of the photosensitive member cartridge and the developing cartridge do not incline during the movement of the cartridges. Therefore, the spacing state between the photosensitive drum and the transfer belt and the spaced state between the photosensitive drum and the developing roller can further be stabilized.

(Embodiment 3)

0154<figref idref="f0032 f0035">Figure 37-Figure 42</figref> illustrates Embodiment 3 of the present invention.

0155In Embodiment 2, the photosensitive member unit (photosensitive member cartridge) and the developing unit (developing cartridge) are mounted individually to the drawer member. In this embodiment, the photosensitive member unit is fixed to the drawer member, and the developing unit (developing cartridge) is mounted to the drawer member. In Embodiments 1, 2, the contacting and spacing member moves in the moving direction of the drawer member. In this embodiment, the contacting and spacing member moves in a direction perpendicular to the moving direction of the drawer member. The fundamental structures except for the structures relating to the drawer member and the contacting and spacing member are the same as with the foregoing embodiments, and the description as to the common structures will be omitted when appropriate. The structural portions which are the same as with the foregoing embodiments are assigned, and the description therefor will be omitted.

< Mounting portion for drawing unit (drawer member (supporting member))>

0156Mainly referring to <figref idref="f0032">Figure 37</figref>, the mounting portion for the drawing unit (drawer member) will be described. <figref idref="f0032">Figure 37</figref> is a perspective view illustrating a mounting portion of the drawing unit in the main assembly of the apparatus of the image forming apparatus according to Embodiment 3 of the present invention. In <figref idref="f0032">Figure 37</figref>, a scanner unit or the like of the members (parts) of the main assembly of the apparatus is omitted for better illustration of the structure of the mounting portion. Parts (a) and (b) in <figref idref="f0032">Figure 37</figref> are perspective views as seen in different directions.

0157On an internal wall surface of the main assembly frame of the apparatus, there are provided opposing guiding members 14RX, 14LX for guiding a moving direction of a drawing unit U3 which will be described hereinafter. The guiding members 14RX, 14LX are rail-like members each having a channel-like section for guiding a portion-to-be-guided 13a, 13b, 13c, 13d (<figref idref="f0033">Figure 38</figref>) of the drawer member 63X which will be described hereinafter. The guiding members 14RX, 14LX extend substantially in the horizontal direction from a neighborhood of an entrance of the main assembly of the apparatus (neighborhood of door 10) to the rear side so as to guide the drawer member 63X from a position outside of the main assembly of the apparatus to a position accommodating it in the main assembly of the apparatus.

0158Above the guiding members 14RX, 14LX, there is provided urging members 65X, 66X for urging and positioning the developing cartridge 60X which is a developing unit which will be described hereinafter, in a predetermined position. Urging members 65X, 66X moves downwardly by a driving force from the main assembly side of the apparatus, so that the developing cartridge 60X is urged, and are provided in order to position the developing cartridge 60X to a predetermined position in the main assembly of the apparatus.

0159Below the guiding member 14LX, there are provided four developing device coupling members 26 for transmitting the drive to the developing cartridge 60X. The four developing device coupling members 26 are arranged horizontally at substantially regular intervals corresponding to the developing cartridges 60X at four positions. The developing device coupling member 26 transmits the driving force from an unshown driving source to the developing cartridge 60X. In the state that the door 10 is open, the developing device coupling member 26 is retracted inside the side wall as shown in (b) of <figref idref="f0032">Figure 37</figref>, or in interrelation with closing of the door 10, it enters the developing cartridge 60X side.

<Drawing unit>

0160Referring to <figref idref="f0033">Figures 38 and 39</figref>, the drawing unit U3 according to Embodiment 3 of the present invention will be described in detail. <figref idref="f0033">Figure 38</figref> is a perspective view of the drawing unit for the image forming apparatus of Embodiment 3 of the present invention. <figref idref="f0033">Figure 39</figref> is a schematic sectional view of the drawing unit for the image forming apparatus of Embodiment 3 of the present invention. In the four drawing units U3 of this embodiment, have fundamentally the same structures and are arranged in the drawing direction. Therefore, in <figref idref="f0033">Figures 38 and 39</figref>, only one fundamental structure is given reference numerals for simplicity of illustration.

0161In this embodiment, there is provided a drawer member 63X as a supporting member which is movable between an inside position which is inside the main assembly of the apparatus and in which it supports the photosensitive drum 1 and demountably supports the developing cartridges 60X and an outside position outside the main assembly of the apparatus. To the drawer member 63X, the photosensitive drum 1, the charging means 2, the cleaning means 6 and the residual toner container 30 or the like are fixed. In addition, a contacting and spacing unit 80 is provided on the drawer member 63X. Thus, the drawing unit U3 of this embodiment is constituted by the drawer member 63X, the photosensitive drum 1, the charging means 2, the cleaning means 6, the residual toner container 30, and the contacting and spacing unit 80 and so on.

0162Four corners of the drawer member 63X are provided with portions-to-be-guided 13a, 13b, 13c, 13d to be guided by the guiding members 14RX, 14LX of the main assembly of the apparatus. The portions-to-be-guided 13a, 13c are guided by the guiding members 14RX, and the portions-to-be-guided 13b, 13d are guided by the guiding members 14LX. The portions-to-be-guided 13a, 13b are projected outwardly from the lateral sides, and extends in the drawing direction so that the drawing unit U3 does not tilt in the drawing position. The portions-to-be-guided 13c, 13d are of circular column configuration and project outwardly of the lateral sides.

0163In the side wall of one of the drawer members 63X, an opening 131 for passing the developing device coupling member 26 is provided. The developing device coupling member 26 is constituted such that it enters the opening 131 in interrelation with the closing operation. The developing device coupling member 26 having passed through the opening 131 is brought into engagement with a coupling member 45X (<figref idref="f0034">Figure 40</figref>) of the developing cartridge 60X. By this, the driving force is transmitted from an unshown driving source of the main assembly side of the apparatus to the developing cartridge 60X through the developing device coupling member 26 of the main assembly side of the apparatus and the coupling member 45X of the developing cartridge 60X.

0164The structure relating to positioning of the developing cartridge 60X relative to the drawer member 63X will be described.

0165The developing cartridge 60X is mounted to a position corresponding to the photosensitive drum 1 in the drawer member 63X. On each side of a region passed by the mounting developing cartridge 60X, there is provided a guide portion 13q, 13r for guiding the developing cartridge 60X into the drawer member 63X. Each guide portion 13q, 13r is provided with an elongated groove. A bottom portion of the groove of the guide portion 13q functions as a positioning portion for positioning the developing cartridge 60X. The opening 13m is provided adjacent to the lower end of the front side guide portion 13q in <figref idref="f0033">Figure 38</figref>.

0166Inside the guide portion 13r, the contacting and spacing unit 80 is provided. The contacting and spacing unit 80 comprises a contacting and spacing member 81 supporting the developing cartridge 60X, and a spring 82 which is an urging member for urging the contacting and spacing member 81 upwardly. The contacting and spacing member 81 is movable between a contacting position for contacting the developing roller 40X to the photosensitive drum 1, and a spacing position for spacing the developing roller 40X from the photosensitive drum 1.

0167The contacting and spacing unit 80 of the embodiment is provided at each side of a mounting region of the developing cartridge 60X.

<Mounting of developing cartridge to drawer member>

0168Mainly referring to <figref idref="f0034">Figure 40</figref>, the mounting of the developing cartridge 60X (60Xy, 60Xm, 60Xc, 60Xk) to the drawer member 63X will be described. The developing cartridges 60Xy, 60Xm, 60Xc, 60Xk may be referred to as developing cartridge 60X, without the last suffixes indicating the colors when appropriate. Here, y indicates yellow developer, m indicates magenta developer, c indicates cyan developer, and k indicates black developer.

0169<figref idref="f0034">Figure 40</figref> is a perspective view illustrating behavior in the mounting of the developing cartridge to the drawer member in the image forming apparatus of Embodiment 3 of the present invention. In mounting the developing cartridge, the drawer member 63X has been drawn out of the main assembly of the apparatus, but in <figref idref="f0034">Figure 40</figref>, the main assembly of the apparatus is omitted.

0170The developing cartridges 60X are mounted to the mounting portions, respectively, of the drawer member 63X. The user mounts the developing cartridge 60X in the direction of an arrow C which is substantially the direction of gravity.

0171Each of the side surfaces of the developing cartridge 60X is provided with a projection 61X. The projection 61X is guided by the guide portion 13r provided on the drawer member 63X. An outer periphery of a coupling member 45X provided on one of the side surfaces of the developing cartridge 60X is covered by a cylindrical rib. The cylindrical rib functions as a portion-to-be-guided to be guided by the guide portion 13q provided on the drawer member 63X. The other side surface of the developing cartridge 60X is provided with a portion-to-be-guided (unshown) to be guided by the guide portion 13q provided on the drawer member 63X.

0172When mounting the developing cartridge 60X, the portions-to-be-guided are first engaged with guide portions 13q of the drawer member 63X. Then, the projections 61X of the developing cartridge 60X are engaged with the guide portions 13r of the drawer member 63X.

0173In this manner, the developing cartridge 60X is mounted in the drawer member 63X by being guided by the guide portions 13q, 13r.

0174Here, the developing cartridge 60X is mounted to the drawer member 63X in the state that the projections 61X is placed on the contacting and spacing member 81. The contacting and spacing member 81 is urged upwardly by the spring 82 as described hereinbefore, so that the developing cartridge 60X is not mounted completely only by the weight of the developing cartridge 60X. In other words, the developing cartridge 60X is above a completely mounted position (capable of image forming operation), and the developing roller 40X is spaced from the photosensitive drum 1. The pair of portions-to-be-guided of the developing cartridge 60X is not contacted to the positioning portion (bottom portion of groove) in the guide portion 13q for positioning the developing cartridge 60X.

0175Therefore, the developing roller 40X does not contact the photosensitive drum 1 only by mounting the developing cartridge 60X to the drawer member 63X. Therefore, in the mounting operation of the developing cartridge 60X, the state that the surface of the developing roller 40X and the surface of the photosensitive drum 1 are spaced from each other can be maintained. Thus, the damage to the surface of the photosensitive drum 1 due to the mounting operation of the developing cartridge 60X can be suppressed. The position in which the developing roller 40X and the photosensitive drum 1 can be spaced from each other is called spacing position similarly to the foregoing embodiments.

<Positioning structure for developing cartridge>

0176Mainly referring to <figref idref="f0035">Figures 41 and 42</figref>, the positioning structure for positioning the developing cartridge 60X in the main assembly of the apparatus will be described. <figref idref="f0035">Figure 41</figref> is a schematic sectional view illustrating a state in which the developing cartridge is mounted, and the image forming operation is not carried out in the image forming apparatus of Embodiment 3 according to the present invention. <figref idref="f0035">Figure 42</figref> is a schematic sectional view illustrating a state in which the positioning of the developing cartridge is completed (state capable of image formation) in the image forming apparatus of Embodiment 3 according to the present invention. In <figref idref="f0035">Figures 41 and 42</figref>, only the members of the members of the main assembly side of the apparatus which relate to the positioning of the developing cartridge.

0177When image formation instructions are produced, the developing roller 40X of the developing cartridge 60X is moved from the position (<figref idref="f0035">Figure 41</figref>) spaced from the photosensitive drum 1 to the position contacting to the photosensitive drum 1 (<figref idref="f0035">Figure 42</figref>). This enables image forming operation. The operations will be described.

0178The main assembly of the apparatus is provided with the pair of urging members 65X, 66X. The urging members 65X, 66X are driven by an unshown driving source to move downwardly in response to the image formation instructions (image formation signal). The urging members 65X, 66X downwardly urge the projections 61X of the both side surfaces of the developing cartridge 60X. By urging force, the pair of the projections 61X pushes down the contacting and spacing member 81 against the urging force of the spring 82. By this, the portions-to-be-guided of the developing cartridge 60X are moved downwardly along the guide portion 13q and are stopped by the positioning portion (bottom portion of groove).

0179In this manner, the developing cartridge 60X is positioned. In this state, the developing roller 40X contacts to the photosensitive drum 1 so that the image forming operation becomes possible (<figref idref="f0035">Figure 42</figref>). The position in which the contacting and spacing member 81 is capable of contacting the surface of developing roller 40X to the surface of the photosensitive drum 1 is called contacting position.

0180In this manner, also in this embodiment, similarly to the foregoing embodiments, the contacting and spacing member 81 is positioned in the contacting position only when the image formation is carried out, and is positioned in the spacing position when the image forming operation is not carried out. By this, the state of the developing roller 40X not contacting to the photosensitive drum 1 can be established, when the image forming operation is not carried out, namely, during drawing the drawing unit U3 (drawer member 63 X) outwardly, and so on. Therefore, the deteriorations of various members can be suppressed, and the service lives can be extended.

0181Also in this embodiment, the contacting and spacing member 81 is provided in the drawer member 63X. Therefore, similarly to the cases of foregoing embodiments, the apparatus can be downsized.

[BRIEF DESCRIPTION OF THE DRAWINGS]

0182<ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">Figure 1</figref> is a schematic sectional view of a whole image forming apparatus according to Embodiment 1 of the present invention.</li><li><figref idref="f0002">Figure 2</figref> is a schematic sectional view illustrating the state that a drawer unit in the image forming apparatus according to Embodiment 1 of the present invention is in an outside position.</li><li><figref idref="f0003">Figure 3</figref> is a perspective view illustrating a mounting portion for a drawer member in a main assembly of the image forming apparatus according to Embodiment 1 of the present invention.</li><li><figref idref="f0003">Figure 4</figref> is a perspective view illustrating the mounting portion for the drawer member in the main assembly of the image forming apparatus according to Embodiment 1 of the present invention.</li><li><figref idref="f0004">Figure 5</figref> is a perspective view of the drawer unit in the image forming apparatus according to Embodiment 1 of the present invention.</li><li><figref idref="f0005">Figure 6</figref> is a perspective view of the drawer unit in the image forming apparatus according to Embodiment 1 of the present invention.</li><li><figref idref="f0006">Figure 7</figref> is a schematic sectional view of a process cartridge according to Embodiment 1 of the present invention.</li><li><figref idref="f0006">Figure 8</figref> is a perspective view of the process cartridge according to Embodiment 1 of the present invention.</li><li><figref idref="f0007">Figure 9</figref> is a perspective view illustrating a state that the process cartridge according to Embodiment 1 of the present invention is mounted to the drawer unit (drawer member).</li><li><figref idref="f0008">Figure 10</figref> is a perspective view illustrating the state that the process cartridge according to Embodiment 1 of the present invention is mounted to the drawer member.</li><li><figref idref="f0009">Figure 11</figref> is a schematic view showing the state that the process cartridge is mounted to the drawer member.</li><li><figref idref="f0010">Figure 12</figref> is a perspective view illustrating the state that the drawer unit according to Embodiment 1 of the present invention is mounted into the main assembly.</li><li><figref idref="f0011">Figure 13</figref> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment 1 of the present invention is mounted in the main assembly.</li><li><figref idref="f0012">Figure 14</figref> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment 1 of the present invention is mounted in the main assembly, and a door is open.</li><li><figref idref="f0013">Figure 15</figref> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment 1 of the present invention is mounted in the main assembly, and the door closes.</li><li><figref idref="f0013">Figure 16</figref> is a perspective view illustrating the state immediately after the image formation instruction in the drawer unit according to Embodiment 1 of the present invention.</li><li><figref idref="f0014">Figure 17</figref> is a schematic sectional view illustrating the state in the course of the drawer unit according to Embodiment 1 of the present invention being mounted in the main assembly and shifting to an image forming operation.</li><li><figref idref="f0015">Figure 18</figref> is a perspective view illustrating the state in the partway of shifting to the image forming operation in the drawer unit according to Embodiment 1 of the present invention.</li><li><figref idref="f0016">Figure 19</figref> is a schematic sectional view illustrating the state in the partway of shifting to the image forming operation in the image forming apparatus according to Embodiment 1 of the present invention.</li><li><figref idref="f0017">Figure 20</figref> is a perspective view illustrating the state of the partway shifting to the image forming operation in the drawer unit according to Embodiment 1 of the present invention.</li><li><figref idref="f0018">Figure 21</figref> is a schematic sectional view illustrating the state that the image forming operation in the image forming apparatus according to Embodiment 1 of the present invention is enabled.</li><li><figref idref="f0019">Figure 22</figref> is a perspective view of a developing cartridge according to Embodiment 2 of the present invention.</li><li><figref idref="f0020">Figure 23</figref> is a perspective view of a photosensitive member cartridge according to Embodiment 2 of the present invention.</li><li><figref idref="f0021">Figure 24</figref> is a perspective view of the drawer unit in the image forming apparatus according to Embodiment 2 of the present invention.</li><li><figref idref="f0021">Figure 25</figref> is a perspective view of the drawer unit in the image forming apparatus according to Embodiment 2 of the present invention.</li><li><figref idref="f0022">Figure 26</figref> is a perspective view illustrating the state that the photosensitive member cartridge and the developing cartridge according to Embodiment 2 of the present invention are mounted to the drawer member.</li><li><figref idref="f0023">Figure 27</figref> is a perspective view illustrating the state that the photosensitive member cartridge and the developing cartridge according to Embodiment 2 of the present invention are mounted to the drawer member.</li><li><figref idref="f0024">Figure 28</figref> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment 2 of the present invention is mounted in the main assembly.</li><li><figref idref="f0025">Figure 29</figref> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment 2 of the present invention is mounted in the main assembly.</li><li><figref idref="f0026">Figure 30</figref> is a schematic sectional view illustrating the state that mounting of the drawer unit according to Embodiment 2 of the present invention is done in the main assembly, and the door is open.</li><li><figref idref="f0027">Figure 31</figref> is a schematic sectional view illustrating the state that the drawer unit according to Embodiment 2 of the present invention is mounted in the main assembly and the door closes.</li><li><figref idref="f0028">Figure 32</figref> is a perspective view illustrating the state immediately after the image formation instruction in the drawer unit according to Embodiment 2 of the present invention.</li><li><figref idref="f0029">Figure 33</figref> is a schematic sectional view illustrating the drawer unit according to Embodiment 2 of the present invention, which is mounted in the main assembly and, and which is in the partway of shifting to the image forming operation.</li><li><figref idref="f0027">Figure 34</figref> is a schematic sectional view illustrating the state in the course of the shifting to the image forming operation in the image forming apparatus according to Embodiment 2 of the present invention.</li><li><figref idref="f0030">Figure 35</figref> is a schematic sectional view illustrating the state in the course of the shifting to the image forming operation in the image forming apparatus according to Embodiment 2 of the present invention.</li><li><figref idref="f0031">Figure 36</figref> is a schematic sectional view illustrating the state that the image forming operation in the image forming apparatus according to Embodiment 2 of the present invention is enabled.</li><li><figref idref="f0032">Figure 37</figref> is a perspective view illustrating a mounting portion of the drawing unit in the main assembly of the apparatus of the image forming apparatus according to embodiment 3 of the present invention.</li><li><figref idref="f0033">Figure 38</figref> is a perspective view of the drawing unit for the image forming apparatus of embodiment 3 of the present invention.</li><li><figref idref="f0033">Figure 39</figref> is a schematic sectional view of the drawing unit for the image forming apparatus of embodiment 3 of the present invention.</li><li><figref idref="f0034">Figure 40</figref> is a perspective view illustrating behavior in the mounting of the developing cartridge to the drawer member in the image forming apparatus of embodiment 3 of the present invention.</li><li><figref idref="f0035">Figure 41</figref> is a schematic sectional view illustrating a state in which the developing cartridge is mounted, and the image forming operation is not carried out in the image forming apparatus of embodiment 3 according to the present invention.</li><li><figref idref="f0035">Figure 42</figref> is a schematic sectional view illustrating a state in which the positioning of the developing cartridge is completed (state capable of image formation) in the image forming apparatus of embodiment 3 according to the present invention.</li></ul>

[INDUSTRIAL APPLICABILITY]

0183According to the present invention, there is provided a downsized electrophotographic image forming apparatus with which a drawer member mounting a photosensitive drum and a developing unit is mounted into a main assembly of the apparatus, and the developing roller and the photosensitive drum can be contacted and spaced relative to each other is provided.