Electrophotographic image forming apparatus

The present invention relates to an electrophotographic image forming apparatus that forms an image on a recording medium with the cartridge detachably attached.

Here, the electrophotographic image forming apparatus is an device that forms an image on a recording medium by using an electrophotographic image forming process. Examples of the electrophotographic image forming apparatus include, for example, an electrophotographic copying machine, an electrophotographic printer (for example, a laser beam printer, an LED printer, etc.), a facsimile machine, a word processor, and the like. Further, the recording medium is one in which an image is formed by an electrophotographic image forming apparatus, and includes, for example, paper, an OHP sheet, and the like.

Further, the cartridge is, for example, a process cartridge or a developing cartridge, which is detachably attached to the main body of the electrophotographic image forming apparatus and contributes to an image forming process of forming an image on a recording medium. Here, the process cartridge is a process means in which at least one of a charging means, a developing means, and a cleaning means and an electrophotographic photosensitive member are integrally formed into a cartridge and detachably attached to the apparatus main body. is there. Therefore, the process cartridge includes a developing means as a process means and the electrophotographic photosensitive member integrally made into a cartridge and detachably attached to the main body of the electrophotographic image forming apparatus. Further, the process cartridge includes a process means in which a charging means, a developing means or a cleaning means and the electrophotographic photosensitive member are integrally formed into a cartridge and detachably attached to the apparatus main body. A process cartridge having an electrophotographic photosensitive member and a developing means integrally is referred to as a so-called integrated type. Further, a process cartridge having an electrophotographic photosensitive member and a process means other than the developing means integrally is referred to as a so-called separation type.

Here, the process cartridge can be attached to and detached from the image forming apparatus main body by the user himself / herself. Therefore, maintenance of the apparatus main body can be easily performed. The process means acts on the electrophotographic photosensitive member.

Further, the developing cartridge has a developing roller and stores a developing agent (toner) used for developing an electrostatic latent image formed on the electrophotographic photosensitive member by the developing roller. It is detachably attached to the main body of the device. In the case of the developing cartridge, the electrophotographic photosensitive member is attached to the apparatus main body. Alternatively, the electrophotographic photosensitive member is provided on the so-called separable process cartridge (in this case, the process cartridge does not have a developing means). The developing cartridge can also be attached to and detached from the image forming apparatus main body by the user himself / herself. Therefore, maintenance of the apparatus main body can be easily performed.

Therefore, the cartridge includes the so-called integrated type or so-called separate type process cartridge. Further, the cartridge includes a case where a so-called separable process cartridge and the developing cartridge are used as a pair. Further, the cartridge includes a case where the electrophotographic photosensitive member is fixedly attached to the apparatus main body and the developing cartridge is detachably used so as to act on the electrophotographic photosensitive member.

Conventionally, in an electrophotographic image forming apparatus using an electrophotographic image forming process, a cartridge method has been adopted in which a cartridge can be attached to and detached from the main body of the electrophotographic image forming apparatus. As this cartridge, a process cartridge in which an electrophotographic photosensitive member drum (hereinafter, referred to as a photosensitive member drum) and a process means acting on the photosensitive member drum are integrated is known.

Further, as an image forming apparatus, a device called an in-line method in which a plurality of process cartridges are arranged is known. In this in-line type image forming apparatus, for example, one provided with a process cartridge for each color of yellow, magenta, cyan, and black is known. Then, the laser light (image light) is output from the laser scanner unit, an image for each color is formed on the photoconductor drum provided in each cartridge, and the images of the respective colors are superposed to form a full-color image.

In such an image forming apparatus, it is known that the opening / closing cover of the image forming apparatus main body is opened and the process cartridge is attached / detached from the opened opening of the apparatus main body. Further, Patent Document 1 discloses a configuration in which the laser scanner unit opens and closes together with the opening / closing cover when the process cartridge is replaced, and the process cartridge is attached / detached from the opened opening.

<p><patcit num="1"><text>Japanese Patent Application Laid-Open No. 2008-216762</text></patcit></p>

<p num="0011"> However, in the above-mentioned conventional example, the process cartridge and the laser scanner unit are respectively positioned on the image forming apparatus main body. Therefore, it is necessary to provide a space for preventing the laser light output from the laser scanner unit from interfering with the process cartridge. As a result, the parts cannot be efficiently arranged in the space inside the apparatus main body, and the size of the apparatus main body may increase.</p><p num="0012"> An object of the present invention is to minimize the space for preventing the laser light output from the laser scanner unit from interfering with the process cartridge, and to efficiently arrange parts in the space inside the device body to reduce the size of the device body. It is to make it smaller.</p>

<p num="0013"> In order to solve the above problems, the present invention is an electrophotographic image forming apparatus in which a cartridge having a process means acting on an electrophotographic photosensitive member is detachably attached to an apparatus main body to form an image on a recording medium. An opening provided in the main body for attaching and detaching the cartridge, an opening / closing member provided in the main body of the device for opening and closing the opening, and an opening / closing member provided in the opening / closing member to expose the electrophotographic photosensitive member. An exposure device to be used, a first positioning unit provided in the main body of the device for positioning the downstream side in the mounting direction of the cartridge, and an upstream side in the mounting direction of the cartridge provided in the exposure device by closing the opening / closing member. It is characterized by having a second positioning portion that directly engages with and positions the upstream side in the mounting direction of the cartridge.</p>

<p num="0014"> According to the present invention, it is possible to minimize the space with the cartridge while accurately securing the path of the light output from the exposure apparatus. As a result, the parts can be efficiently arranged in the space inside the apparatus main body, the positioning configuration can be simplified, and the apparatus main body can be downsized.</p>

<figref num="1">(A) is a perspective view of the electrophotographic image forming apparatus according to the first embodiment, and (b) is a cross-sectional view of the electrophotographic image forming apparatus according to the first embodiment.</figref><figref num="2">(A) is a cross-sectional view in a state where the opening / closing cover of the electrophotographic image forming apparatus according to the first embodiment is opened, and (b) is a cross-sectional view in a state where the process cartridge of the electrophotographic image forming apparatus according to the first embodiment is taken out. FIG. 3C is a perspective view of the positioning configuration of the main unit and the process cartridge according to the first embodiment, and the state in which the process cartridge to be replaced is taken out.</figref><figref num="3">(A) is a perspective view of the process cartridge according to the first embodiment, (b) is a sectional view of the process cartridge according to the first embodiment, and (c) is a side view of the process cartridge according to the first embodiment.</figref><figref num="4">(A) is a cross-sectional view showing a state in which the developing roller of the image forming apparatus according to the first embodiment is in contact with the photoconductor drum, and (b) is a sectional view showing a state in which the developing roller of the image forming apparatus according to the first embodiment is exposed to light. It is sectional drawing which showed the state which was separated from the body drum.</figref><figref num="5">(A) and (b) are perspective views explaining the positioning configuration of the laser scanner unit and the process cartridge according to the first embodiment.</figref><figref num="6">It is a side view explaining the positioning structure of the laser scanner unit and process cartridge which concerns on 1st Embodiment.</figref><figref num="7">(A) and (b) are perspective views explaining the positioning configuration of the laser scanner unit and the process cartridge according to the second embodiment.</figref><figref num="8">(A) is a perspective view for explaining the positioning configuration of the laser scanner unit and the process cartridge according to the third embodiment, and (b) is a side view for explaining the positioning configuration of the laser scanner unit and the process cartridge according to the third embodiment. is there.</figref><figref num="9">(A) and (b) are perspective views explaining the positioning configuration of the laser scanner unit and the process cartridge according to the fourth embodiment.</figref><figref num="10">It is a side view explaining the pressing structure of the laser scanner unit and process cartridge which concerns on 4th Embodiment.</figref><figref num="11">It is a side view explaining the contact state of the pressing structure of the laser scanner unit and the process cartridge which concerns on 4th Embodiment.</figref><figref num="12">(A) and (b) are perspective views explaining the positioning configuration of the laser scanner unit and the process cartridge according to the fifth embodiment.</figref><figref num="13">It is a side view explaining the structure which shields and opens the exposed part of the laser scanner unit which concerns on 5th Embodiment.</figref><figref num="14">(A) is a cross-sectional view of an image forming apparatus for exchanging a process cartridge by rotating the opening / closing cover according to another embodiment upward to the image forming apparatus main body, and (b) is an image of an opening / closing cover according to another embodiment. It is sectional drawing of the state which took out the process cartridge of the image forming apparatus which rotates upward of the forming apparatus main body, and replaces a process cartridge.</figref><figref num="15">(A) is a perspective view of a state in which the developing unit and the photoconductor drum unit according to another embodiment are combined with a process cartridge that can be replaced separately, and (b) is a separate view of the developing unit and the photoconductor drum unit according to another embodiment. It is a perspective view of the state which the process cartridge which can be exchanged by a body is separated.</figref><figref num="16">It is a side view explaining the positioning structure of the laser scanner unit and the process cartridge in the process cartridge which can exchange the development unit and the photoconductor drum unit of another embodiment separately.</figref><figref num="17">(A) is a perspective view of a process cartridge in which the developing unit and the photoconductor drum unit according to another embodiment can be replaced separately, a positioning configuration of the main body unit and the process cartridge, and a state in which the process cartridge to be replaced is taken out. Is a sectional view showing a positioning configuration of a main body unit and a process cartridge in a process cartridge in which the developing unit and the photoconductor drum unit according to another embodiment can be replaced separately, and a state in which the process cartridge to be replaced is taken out.</figref>

Hereinafter, preferred embodiments of the present invention will be described in detail exemplarily with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments should be appropriately changed depending on the configuration of the apparatus to which the present invention is applied and various conditions. Therefore, unless otherwise specified, the scope of the present invention is not intended to be limited to them.

[First Embodiment] The electrophotographic image forming apparatus according to the first embodiment will be described with reference to FIGS. 1 to 6. 1 and 2 are explanatory views of the electrophotographic image forming apparatus according to the first embodiment. Here, a laser beam printer is illustrated as an electrophotographic image forming apparatus, and the overall configuration and functions of the laser beam printer will be described.

In the following description, the front side (front) of the device main body is the front side of the device main body which is the operator side. The side opposite to the front side when viewed from the operator side is the rear side (rear side) of the device main body and the back side of the device main body.

[Overview of image forming apparatus] FIG. 1A is an external perspective view of the image forming apparatus. FIG. 1B is a cross-sectional view of the image forming apparatus. As shown in FIGS. 1 (a) and 1 (b), the image forming apparatus is a four-color full-color laser printer using an electrophotographic process. The image forming apparatus executes image forming on a recording medium (paper) based on an electric image signal input from an external host device (not shown) such as a personal computer, an image reader, or a remote fax machine.

A laser scanner unit 10, a removable process cartridge P (PY, PM, PC, PK), an intermediate transfer unit 40, a fixing device 50, a feeding unit 60, and the like are installed in the apparatus main body 100 of the image forming apparatus. ing.

The feeding unit 60 includes a feeding cassette 62, a feeding roller 61, a separation pad 63, and the like. The feed cassette 62 can be freely taken in and out from the front side of the main body of the apparatus (front loading). The feeding roller 61 is rotationally driven in the counterclockwise direction in the drawing (direction of arrow a in FIG. 1B) at a predetermined control timing, and the feeding roller 61 and the separation pad 63 cooperate with each other to drive the feeding cassette 62. One sheet of paper S, which is a recording medium loaded inside, is separately fed. The separately fed paper S is fed to the nip portion of the intermediate transfer body unit 40 and the secondary transfer roller 41 by the paper transport roller pair 64.

The photoconductor drum 21 is rotated in the clockwise direction in the drawing (direction of arrow b in FIG. 1B), and the outer peripheral surface thereof is electrostatically latent by the laser light L from the exposed portion 16 of the laser scanner unit 10. Images are formed sequentially. Subsequently, the electrostatic latent image is developed by the developing roller 32 to form a toner image.

The toner image formed on the photoconductor drum 21 is transferred (primary transfer) to the intermediate transfer body unit 40. When forming a color image, yellow, magenta, cyan, and black colors are developed on each photoconductor drum 21, and the toner images formed on the respective photoconductor drums 21 are sequentially transferred (primary transfer) to the intermediate transfer unit 40. ..

Next, the toner image formed on the intermediate transfer body unit 40 is transferred (secondary transfer) to the paper S sent to the nip portion of the intermediate transfer body unit 40 and the secondary transfer roller 41. After the toner image is transferred to the intermediate transfer body unit 40, the transfer residual toner remaining on the surface of the photoconductor drum 21 is removed by the cleaner 22. The transfer residual toner removed by the cleaner 22 is stored in the waste toner chamber 27 (see FIG. 3B) provided in the photoconductor drum unit 20.

Further, the paper S on which the toner image is transferred is sent to the nip portion of the fixing film 51 and the pressure roller 52 arranged in the fixing device 50, where it is heated and pressed to fix the toner image on the paper S. .. The paper S on which the toner image is fixed is discharged onto the discharge tray 70 by the discharge roller pair 71.

After transferring the toner image to the paper, the transfer residual toner remaining on the surface of the intermediate transfer unit 40 is electrostatically adhered to the surface of the photoconductor drum 21 in the primary transfer portion of the process cartridge PY, for example. It is removed by the cleaner 22. The transfer residual toner removed by the cleaner 22 is stored in the waste toner chamber 27.

Each process cartridge integrally has an electrophotographic photosensitive member and a process means (process apparatus) that acts on the electrophotographic photosensitive member. Here, as shown in FIGS. 3A and 3B, each process cartridge P is composed of a photoconductor drum unit 20 (first unit) and a developing unit 30 (second unit). ing.

The photoconductor drum unit 20 has a photoconductor drum 21 as an electrophotographic photoconductor. Further, the photoconductor drum unit 20 includes a charging roller (charging means) 24 as a process means acting on the photoconductor drum 21, and a cleaning device (cleaning means) 22 for removing the developer T remaining on the surface of the photoconductor drum 21. And a photoconductor case 23. A plurality of photoconductor drum units 20 are arranged with respect to the intermediate transfer body unit 40, and are arranged at predetermined intervals.

The developing unit 30 is connected to the photoconductor drum unit 20. The developing unit 30 is oscillatingly coupled to the photoconductor drum unit 20 about the oscillating axis. The developing unit 30 includes a developer case 31 that houses the developer T to be supplied to the photoconductor drum 21, a developing roller (development means) 32 that supplies the developer T to the photoconductor drum 21, and a developer to the developing roller 32. It has a supply roller 33 for supplying the developer T of the case 31.

The developing roller 32 may be in contact with the photoconductor drum 21 as shown in FIG. 4A, or may be separated from the photoconductor drum 21 as shown in FIG. 4B. In FIG. 4B, the spacer 37 engaged with the end of the developing roller 32 is brought into contact with the photoconductor drum 21 so that the position of the developing roller 32 is determined while maintaining a certain distance from the photoconductor drum 21. I'm letting you.

A laser scanner unit (exposure apparatus) 10 is arranged in the front portion (front side of the apparatus main body) of the process cartridges PY, PM, PC, and PK. The laser scanner unit 10 outputs laser light L modulated according to image information of each color input from an external host device, and scans and exposes each photoconductor drum 21.

[Overview of process cartridge] Next, the process cartridges PY, PM, PC, and PK that are detachably attached to the apparatus main body 100 of the image forming apparatus will be described.

FIG. 3A is an external perspective view of the process cartridge. The process cartridges PY, PM, PC, and PK have the same electrophotographic process mechanism, and the color of the toner contained therein and the filling amount of the toner are different from each other.

The process cartridges PY, PM, PC, and PK are horizontally long assemblies in which the axial direction of the photoconductor drum 21 is the left-right direction and the left-right direction is the longitudinal direction. The photoconductor drum 21 is rotatably supported and arranged between the bearing portions (not shown) arranged on the right side surface portion and the left side surface portion of the process cartridge frame. The rotating shaft 21a of the photoconductor drum 21 and the photoconductor drum positioning unit 43 (electrophotographic photosensitive member positioning unit) provided on the intermediate transfer body unit 40 are fitted to the intermediate transfer body unit 40 of the photoconductor drum 21. The position is decided. Although the photoconductor drum positioning unit provided in the intermediate transfer unit 40 has been illustrated here as the electrophotographic photosensitive member positioning unit, the present invention is not limited to this. For example, the apparatus main body 100 that supports the intermediate transfer body unit 40 may be provided with an electrophotographic photosensitive member positioning unit.

On the drive side, which is one side in the axial direction, a photoconductor drum drive gear 25 as a drive input unit of the photoconductor drum 21 and a developing roller drive gear 36 as a drive input unit of the developing roller 32 are provided. An electrical contact portion (not shown) is arranged on the left side surface portion.

The photoconductor drum 21 and the developing roller 32 are engaged with each of the photoconductor drum drive gear 25 and the developing roller driving gear 36 of the process cartridges PY, PM, PC, and PK and the drive output gear (not shown) of the image forming apparatus main body. The drive is transmitted to.

FIG. 3B is a cross-sectional view of the process cartridge as viewed from the other side of the process cartridge in the axial direction of the photoconductor drum. FIG. 3C is a side view of the process cartridge. The photoconductor drum 21 is rotationally driven by receiving a driving force from a drive output gear (not shown) of the image forming apparatus main body 100. The charging roller 24 is a contact charging type charging member that comes into contact with the photoconductor drum 21 and rotates in a driven manner. The cleaning device 22 is an elastic rubber blade, and is arranged so that the tip end portion thereof is in contact with the photoconductor drum 21 in the counter direction with respect to the rotation direction of the photoconductor drum 21. The cleaner 22 serves to remove the toner remaining on the photoconductor drum 21. The transfer residual toner removed by the cleaner 22 is housed in a waste toner chamber 27 provided in the photoconductor case 23.

The developing unit 30 has a developing roller 32 as a developing means and a developing blade 35. As shown in FIG. 3B, the developing blade 35 is arranged with its tip end in contact with the developing roller 32. The developing blade 35 serves to regulate the toner to a thin layer on the peripheral surface of the developing roller 32. As shown in FIG. 3C, both ends of the developing roller rotating shaft 32a of the developing roller 32 are positioned with respect to the photoconductor drum 21 by the positioning holes 26 provided in the photoconductor drum unit 20. It is supported while engaging.

[Overview of cartridge positioning method] 2A and 2B are cross-sectional views of an image forming apparatus main body 100 for explaining a method of exchanging process cartridges PY, PM, PC, and PK in the present embodiment. FIG. 2C is a positioning configuration of the main unit and the process cartridge, and is a perspective view of a state in which the process cartridge to be replaced is taken out.

The opening / closing cover 101 as an opening / closing member is arranged on the front side (front side) of the image forming apparatus main body 100, and is rotatably provided around the hinge portion 102. The opening / closing cover 101 closes the opening 104 provided in the apparatus main body 100 so as to be openable. The opening 104 is provided in the image forming apparatus main body 100 and is an opening 104 for attaching and detaching the process cartridge P. The opening / closing cover 101 is brought into a state in which the opening / closing cover 101 is opened by rotating the opening / closing cover 101 in the direction of the arrow d in FIG. 2A about the hinge portion 102. The laser scanner unit 10 arranged on the front surface (front side) of the process cartridges PY, PM, PC, and PK is provided on the opening / closing cover 101, and rotates together with the opening / closing cover 101 toward the front side of the image forming apparatus main body 100. .. As a result, the opening 104 of the apparatus main body 100 is opened, and the process cartridges PY, PM, PC, and PK can be accessed. That is, the process cartridges PY, PM, PC, and PK can be taken out from the image forming apparatus main body 100 in the direction of the arrow e in FIG. 2B.

When mounting the process cartridges PY, PM, PC, and PK on the image forming apparatus main body 100, the opening / closing cover 101 is opened in the reverse procedure, and the process cartridges PY, PM, PC, and PK are stored inside the image forming apparatus main body 100. To do.

5 (a) and 5 (b) are perspective views of a state in which the opening / closing cover is opened and a state in which the opening / closing cover is closed when the process cartridge is replaced. 5 (a) and 5 (b) show an intermediate transfer unit 40, a process cartridge PY, PM, PC, PK, a laser scanner unit 10, an image forming apparatus main body frame 15, and an opening / closing cover 101. Shown. Further, since the configurations of the process cartridges PY, PM, PC, and PK are the same, the process cartridge P will be described in the following description.

The laser scanner unit 10 has a rotation stop portion 12 for stopping the rotation of the process cartridge P. The rotation stop portion 12 included in the laser scanner unit 10 is a positioning means (second positioning portion) for positioning the laser scanner unit 10 and the process cartridge P, and engages with the process cartridge P by closing the open / close cover 101. .. The rotation stop portions 12 included in the laser scanner unit 10 are provided on both sides in a direction intersecting the attachment / detachment direction of the process cartridge.

The process cartridge P has a developing unit rotation stop 34 as a cartridge positioning unit that engages with the rotation stop 12 of the laser scanner unit 10. The development unit rotation stop portions 34 are provided at both ends of the development unit 30 in each process cartridge P, and engage with the rotation stop portions 12 provided in the laser scanner unit 10 to stop the rotation of the process cartridge P. ..

The image forming apparatus main body 100 has a main body positioning unit 103 as a device main body positioning means for positioning the laser scanner unit 10 on the apparatus main body 100. The main body positioning unit 103 is provided on the main body frame 15 of the device main body 100 and engages with the laser scanner unit 10. Here, the main body positioning portions 103 are provided on both sides in a direction intersecting the attachment / detachment direction of the process cartridge, one of which is a round hole and the other of which is an oblong hole.

The laser scanner unit 10 is movably held by the opening / closing cover 101 within a predetermined range. The laser scanner unit 10 has a laser scanner unit positioning unit 11 as a third positioning unit that engages with the main body positioning unit 103 and is positioned on the device main body 100 by closing the open / close cover 101.

By closing the opening / closing cover 101 of the laser scanner unit 10, the main body positioning unit 103 provided on the main body frame 15 and the laser scanner unit positioning unit 11 provided on the laser scanner unit 10 are fitted to each other, and the apparatus main body 100 Positioned to. Since the main body positioning unit 103 has a round hole on one side and an oblong round hole on the other side as described above, the laser scanner unit 10 can be accurately positioned with respect to the frame body 15 of the main body of the image forming apparatus.

By closing the opening / closing cover 101, the rotation stop portions 12 provided at both ends of the laser scanner unit 10 and the rotation stop portions 34 of the development unit provided in the development unit 30 of the process cartridge P are engaged with each other. As a result, the position of the developing unit 30 of the process cartridge P with respect to the laser scanner unit 10 is determined, and a gap with the laser beam L output from the laser scanner unit 10 can be reliably obtained with a small clearance.

Further, in each process cartridge P, the rotating shaft 21a of the photoconductor drum 21 and the photoconductor drum positioning portion 43 (first positioning portion) provided on the intermediate transfer body unit 40 are fitted to each other to form the photoconductor drum 21. The position with respect to the intermediate transfer unit 40 is determined (FIG. 2 (c)). Then, as described above, by closing the opening / closing cover 101, the rotation stop portion 12 of the laser scanner unit 10 and the rotation stop portion 34 of the development unit of the process cartridge P are engaged with each other, and the process cartridge for the laser scanner unit 10 is engaged. The position of P is determined. That is, the process cartridge P is positioned by the photoconductor drum positioning portion that fits with the photoconductor drum and the rotation stop portion 12 of the laser scanner unit 10 provided in the apparatus main body 100.

Further, in the rotation stop portions 12 provided at both ends of the laser scanner unit 10, the rotation stop portion 12 on one side engages with the rotation stop portion 34 of the development unit on one side of the process cartridge P with a gap. Further, the rotation stop portion 12 on the other side is fitted with the rotation stop portion 34 of the developing unit on the other side. FIG. 6 shows an engaged state having a gap between the rotation stop portion 12 on one side and the rotation stop portion 34 of the developing unit. As shown in FIG. 6, the rotation stop portion 12 on one side and the rotation stop portion 34 of the development unit are in contact with each other in a state where the outer upper portion of the rotation stop portion 12 and the inner upper portion of the development unit rotation stop portion 34 are in contact with each other. However, the lower outer part of the rotation stop portion 12 and the lower inner part of the rotation stop portion 34 of the developing unit are in non-contact. By doing so, it is possible to suppress poor engagement between the rotation stop portions 12 at both ends and the rotation stop portion 34 of the developing unit due to twisting of the process cartridge P or the like.

The contact state of the rotation stop portion on one side engaged with the gap is not limited to the above-mentioned state. The outer lower portion of the rotation stop portion 12 and the inner lower portion of the development unit rotation stop portion 34 may be in contact with each other, and the outer upper portion of the rotation stop portion 12 and the inner upper portion of the development unit rotation stop portion 34 may be in non-contact. That is, the rotation stop portion 12 on one side and the rotation stop portion 34 of the developing unit that are engaged with the gap may be in contact with each other and non-contact with the other with a gap. ..

As for the relative positional relationship between the developing roller 32 and the photoconductor drum 21, the developing roller 32 is positioned with respect to the photoconductor drum 21 by the positioning hole 26 provided in the photoconductor drum unit 20 as described above. Further, the position of the process cartridge P (development unit 30) is restricted only in the rotation direction by the rotation stop portion 12 provided in the laser scanner unit 10, and the development function is not affected.

As described above, according to the present embodiment, the development unit rotation stop portions 34 provided at both ends of the development unit 30 and the rotation stop portions 12 provided on the laser scanner unit 10 attached to the opening / closing cover 101 form other parts. Directly engage and determine the position without intervention. This makes it possible to reduce the gap between the developing unit 30 and the laser beam L output from the laser scanner unit 10.

As a result, the developing unit 30 arranged in the process cartridges PY, PM, PC, and PK and the laser scanner unit 10 arranged in the image forming apparatus main body 100 are positioned at different positions in the image forming apparatus main body. In comparison, the following effects can be obtained. That is, the gap (space) between the developing unit 30 and the laser scanner unit 10 can be minimized while accurately securing the path of the laser light L output from the developing unit 30 and the laser scanner unit 10. In particular, in the case of a process cartridge in which the developing unit 30 and the photoconductor drum unit 20 are oscillatingly provided as in this embodiment, one unit is positioned by the laser scanner unit 10. Then, the other unit is positioned by the main body portion other than the laser scanner unit 10. As a result, the parts can be efficiently arranged in the space inside the apparatus main body, the positioning configuration can be simplified, and the image forming apparatus main body 100 can be downsized.

[Second Embodiment] The schematic configuration of the image forming apparatus of the second embodiment is the same as that of the image forming apparatus of the first embodiment. Members having the same functions as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted. In this embodiment, the description of the configuration different from that of the first embodiment will be mainly described.

7 (a) and 7 (b) are perspective views of the present embodiment in which the open / close cover is opened and closed when the process cartridge is replaced. Note that FIGS. 7 (a) and 7 (b) show the intermediate transfer unit 40, the process cartridges PY, PM, PC, PK, the laser scanner unit 10, and the open / close cover 101.

The laser scanner unit 10 has a rotation stop portion 12 for stopping the rotation of the process cartridge P. The rotation stop portion 12 included in the laser scanner unit 10 is a positioning portion for positioning the laser scanner unit 10 and the process cartridge P. The rotation stop portions 12 included in the laser scanner unit 10 are provided on both sides in a direction intersecting the attachment / detachment direction of the process cartridge. In the present embodiment, in order to determine the interval between the development units 30 of the process cartridges PY, PM, PC, and PK arranged at predetermined intervals, a convex rotation stop portion 12 is provided between the process cartridges PY, PM, PC, and PK. It is provided. Therefore, in the rotation stop portion 12 of the present embodiment, by closing the opening / closing cover 101, the upper and lower rotation stop portions 12, 12 are directly engaged with the upper end and the lower end of the frame body of each process cartridge P. As a result, the rotation of the process cartridge P (development unit 30) is stopped, and the position is determined in a state where the gap between the process cartridge P (development unit 30) and the laser beam L output from the laser scanner unit 10 is maintained at a constant distance.

In the present embodiment, the rotation stop portion 12 of the laser scanner unit 10 is directly engaged with the frame of the process cartridge P. Therefore, as in the above-described embodiment, the development unit rotation stop is attached to the process cartridge P. It is not necessary to provide the portion 34. Therefore, as compared with the above-described embodiment, the positioning configuration can be further simplified and the cost can be reduced.

As described above, according to the present embodiment, the rotation stop portion 12 provided in the laser scanner unit 10 directly engages with the frame body of the process cartridge P (development unit 30) without interposing other parts to determine the position. .. This makes it possible to reduce the gap between the developing unit 30 and the laser beam L output from the laser scanner unit 10.

As a result, as in the above-described embodiment, the gap (space) between the developing unit 30 and the laser scanner unit 10 is created while accurately securing the path of the laser light L output from the developing unit 30 and the laser scanner unit 10. Can be minimized. As a result, the parts can be efficiently arranged in the space inside the apparatus main body, the positioning configuration can be simplified, and the image forming apparatus main body 100 can be downsized. Further, as compared with the above-described embodiment, the positioning configuration can be simplified and the cost can be reduced.

[Third Embodiment] The schematic configuration of the image forming apparatus of the third embodiment is the same as that of the image forming apparatus of the first embodiment. Members having the same functions as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted. In this embodiment, the description of the configuration different from that of the first embodiment will be mainly described.

8 (a) and 8 (b) are a perspective view of the opening / closing cover when the process cartridge is replaced and a side view of the opening / closing cover in the closed state in the present embodiment. 8 (a) and 8 (b) show the intermediate transfer unit 40, the process cartridges PY, PM, PC, PK, the laser scanner unit 10, and the open / close cover 101.

The laser scanner unit 10 has a rotation stop portion 12 for stopping the rotation of the process cartridge P. The rotation stop portion 12 included in the laser scanner unit 10 is a positioning portion for positioning the laser scanner unit 10 and the process cartridge P. The rotation stop portion 12 included in the laser scanner unit 10 is provided at a central portion in a direction intersecting the attachment / detachment direction of the process cartridge. In the present embodiment, in order to determine the interval between the development units 30 of the process cartridges PY, PM, PC, and PK arranged at predetermined intervals, a convex rotation stop portion 12 is provided at a position corresponding to each process cartridge P. There is.

On the other hand, each process cartridge P has a concave developing unit rotation stop 34 as a cartridge positioning portion that engages with the rotation stop 12 of the laser scanner unit 10. The development unit rotation stop 34 is provided at the center of the development unit 30 in each process cartridge P. The concave development unit rotation stop 34 of the process cartridge P engages with the convex rotation stop 12 provided on the laser scanner unit 10 by closing the open / close cover 101. As a result, the rotation of the process cartridge P (development unit 30) is stopped, and the position is determined in a state where the gap between the process cartridge P (development unit 30) and the laser beam L output from the laser scanner unit 10 is maintained at a constant distance.

As described above, according to the present embodiment, the development unit rotation stop 34 provided in the central portion of the development unit 30 and the rotation stop 12 provided in the laser scanner unit 10 attached to the opening / closing cover 101 form other parts. Directly engage and determine the position without intervention. This makes it possible to reduce the gap between the developing unit 30 and the laser beam L output from the laser scanner unit 10.

As a result, as in the above-described embodiment, the gap (space) between the developing unit 30 and the laser scanner unit 10 is created while accurately securing the path of the laser light L output from the developing unit 30 and the laser scanner unit 10. Can be minimized. As a result, the parts can be efficiently arranged in the space inside the apparatus main body, the positioning configuration can be simplified, and the image forming apparatus main body 100 can be downsized.

[Fourth Embodiment] The schematic configuration of the image forming apparatus of the fourth embodiment is the same as that of the image forming apparatus of the first embodiment. Members having the same functions as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted. In this embodiment, the description of the configuration different from that of the first embodiment will be mainly described.

9 (a) and 9 (b) are a perspective view of the opening / closing cover when the process cartridge is replaced and a side view of the closed state in the present embodiment. 8 (a) and 8 (b) show the intermediate transfer unit 40, the process cartridges PY, PM, PC, PK, the laser scanner unit 10, and the open / close cover 101.

The laser scanner unit 10 has a rotation stop portion 12 for stopping the rotation of the process cartridge P. The rotation stop portion 12 included in the laser scanner unit 10 is a positioning portion for positioning the laser scanner unit 10 and the process cartridge P.

As shown in FIG. 10, the rotation stop portion 12 included in the laser scanner unit 10 is provided so as to be pressed by the rotation stop portion spring 13 in substantially the same direction as the abutting direction of the positioning portion of the process cartridge. ..

In the present embodiment, in order to determine the interval between the development units 30 of the process cartridges PY, PM, PC, and PK arranged at predetermined intervals, a convex rotation stop portion 12 is provided at a position corresponding to each process cartridge P. There is.

On the other hand, each process cartridge P has a concave developing unit rotation stop 34 as a cartridge positioning portion that engages with the rotation stop 12 of the laser scanner unit 10. The development unit rotation stop 34 is provided at the center of the development unit 30 in each process cartridge P. The concave development unit rotation stop 34 of the process cartridge P engages with the convex rotation stop 12 provided on the laser scanner unit 10 by closing the open / close cover 101. As a result, the rotation of the process cartridge P (development unit 30) is stopped, and the position is determined in a state where the gap between the process cartridge P (development unit 30) and the laser beam L output from the laser scanner unit 10 is maintained at a constant distance.

As described above, according to the present embodiment, the development unit rotation stop 34 provided in the development unit 30 and the rotation stop 12 provided in the laser scanner unit 10 attached to the opening / closing cover 101 do not involve other parts. Directly engage and determine the position. This makes it possible to reduce the gap between the developing unit 30 and the laser beam L output from the laser scanner unit 10. Further, since the rotation stop portion 12 is arranged so as to press in substantially the same direction as the abutting direction of the positioning portion of the process cartridge P, it is not necessary to separately arrange a member for urging the process cartridge P.

FIG. 11 is a side view illustrating a contact state of the pressing configuration of the laser scanner unit and the process cartridge in the present embodiment.

By making the contact surfaces S1 and S2 of the rotation stop portion 12 and the rotation stop portion 34 of the developing unit inclined, positioning without play is possible. Further, contact mechanisms for the process cartridge P are provided on the contact surfaces S1 and S2 of the rotation stop portion 12 and the rotation stop portion 34 of the developing unit. The contact mechanism means that the rotation stop portion 34 and the contact surfaces S1 and S2 are provided with contacts for supplying power to the process portion provided in the process cartridge. For example, the power supply of the development bias applied to the developing roller can be performed through the contacts provided on the contact surfaces S1 and S2. By providing such a contact mechanism, the contact pressure can be made larger than the pressing force applied to the process cartridge P. This makes it possible to construct a reliable electrical contact. Further, it is not necessary to separately arrange a contact mechanism for the process cartridge P, and the positioning of the process cartridge P becomes more stable.

As a result, the developing unit 30 arranged in the process cartridges PY, PM, PC, and PK and the laser scanner unit 10 arranged in the image forming apparatus main body 100 are positioned at different positions in the image forming apparatus main body. In comparison, the following effects can be obtained. That is, the gap (space) between the developing unit 30 and the laser scanner unit 10 can be minimized while accurately securing the path of the laser light L output from the developing unit 30 and the laser scanner unit 10. Further, it is not necessary to separately arrange a member for urging the process cartridge P. As a result, the parts can be efficiently arranged in the space inside the apparatus main body, the positioning configuration can be simplified, and the image forming apparatus main body 100 can be downsized.

[Fifth Embodiment] The schematic configuration of the image forming apparatus of the fifth embodiment is the same as that of the image forming apparatus of the fourth embodiment. Members having the same functions as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted. In this embodiment, the description of the configuration different from that of the fourth embodiment will be mainly described.

12 (a) and 12 (b) are a perspective view of the opening / closing cover when the process cartridge is replaced and a side view of the opening / closing cover in the closed state in the present embodiment. Note that FIGS. 12 (a) and 12 (b) show the intermediate transfer unit 40, the process cartridges PY, PM, PC, PK, the laser scanner unit 10, and the open / close cover 101.

FIG. 13A is a side view of the open / close cover opened and closed when the process cartridge is replaced. Note that FIG. 13 shows the process cartridge P and the laser scanner unit 10.

The laser scanner unit 10 has a rotation stop portion 12 for stopping the rotation of the process cartridge P. The rotation stop portion 12 included in the laser scanner unit 10 is a positioning portion for positioning the laser scanner unit 10 and the process cartridge P.

As shown in FIG. 13, the rotation stop portion 12 included in the laser scanner unit 10 is provided by a spring 13 so as to be pressed in substantially the same direction as the abutting direction of the positioning portion of the process cartridge. Further, the rotation stop portion 12 engages with the shielding member 14 that closes the exposure portion 16 of the exposure apparatus, and the shielding member 14 is rotatably arranged around the rotation center 14a.

When the opening / closing cover 101 is opened, the laser scanner unit 10 also moves in the direction of arrow c, and the rotation stop portion 12 moves in the direction of arrow a. That is, the pressure on the process cartridge P is released.

As described above, according to the present embodiment, the development unit rotation stop 34 provided in the development unit 30 and the rotation stop 12 provided in the laser scanner unit 10 attached to the opening / closing cover 101 do not involve other parts. Directly engage and determine the position. This makes it possible to reduce the gap between the developing unit 30 and the laser beam L output from the laser scanner unit 10. Further, since the rotation stop portion 12 is arranged so as to press in a direction substantially parallel to the positioning direction of the process cartridge P, it is not necessary to separately arrange a member for urging the process cartridge P. Further, since the rotation stop portion 12 is engaged with the shielding member 14 at the engaging portion 12a, when the pressure on the process cartridge P is released, the rotation stop portion 12 moves in the direction of the arrow a, and the shielding member 14 is centered on rotation. It rotates around 14a to shield the exposed portion of the exposure apparatus.

As a result, the developing unit 30 arranged in the process cartridges PY, PM, PC, and PK and the laser scanner unit 10 arranged in the image forming apparatus main body 100 are positioned at different positions in the image forming apparatus main body. In comparison, the following effects can be obtained. That is, the gap (space) between the developing unit 30 and the laser scanner unit 10 can be minimized while accurately securing the path of the laser light L output from the developing unit 30 and the laser scanner unit 10. Further, it is not necessary to separately arrange a member for urging the process cartridge P, and the shielding / opening mechanism of the exposed portion of the exposure apparatus can be made with a simpler configuration. Therefore, the parts can be efficiently arranged in the space inside the apparatus main body, the positioning configuration can be simplified, and the image forming apparatus main body 100 can be downsized.

[Other Embodiments] In the above-described embodiment, the laser scanner unit 10 is movably held by the opening / closing cover 101 within a predetermined range and is accurately positioned on the image forming apparatus main body frame 15, but the present invention is limited to this. It's not a thing. The present invention is effective even if the laser scanner unit 10 is positioned and fixed to the opening / closing cover 101 and is not accurately positioned with respect to the image forming apparatus main body frame 15. That is, the position of the developing unit 30 in the process cartridge P is positioned by the rotation stop portion 12 provided in the laser scanner unit 10. As a result, even if the laser scanner unit 10 is positioned and fixed to the opening / closing cover 101, the gap between the developing unit 30 and the laser beam L output from the laser scanner unit 10 can be reliably obtained with a small clearance. ..

Further, in the above-described embodiment, a mode in which the opening / closing cover is rotated forward of the main body of the image forming apparatus to replace the process cartridge is illustrated, but the present invention is not limited to this. For example, as shown in FIGS. 14A and 14B, the opening / closing cover 101 may be configured to rotate and open in the direction of the arrow f above the image forming apparatus with the hinge portion 102 as the center. In this case, the process cartridges PY, PM, PC, and PK can be taken out in the direction of the arrow g above the image forming apparatus. By using the configuration of the present invention for this image forming apparatus, the gap between the laser beam L output from the laser scanner unit 10 and the developing unit 30 arranged in the process cartridges PY, PM, PC, and PK is minimized. can do. Then, the depth direction of the image forming apparatus main body 100 can be reduced.

Further, in the above-described embodiment, the positioning configuration of the developing unit 30 of the process cartridges PY, PM, PC, and PK in which the developing unit 30 and the photoconductor drum unit 20 are integrated is shown. In addition to that, the same effect can be obtained by using the configuration of the present invention in an image forming apparatus using a process cartridge in which the developing unit and the photoconductor drum unit can be exchanged separately. For example, as shown in FIG. 15, a process cartridge in which the developing roller rotating shaft 32a is fitted into the developing unit positioning groove 29 provided in the photoconductor drum unit 20 by the developing unit 30 and the position is determined may be used. As shown in FIGS. 16A and 17B, the photoconductor drum rotation shaft 21a and the photoconductor drum rotation stop 28 provided in the photoconductor drum unit are provided in the intermediate transfer body unit 40. An image forming apparatus that fits in the positioning groove 43 and determines the position may be used.

Further, the positioning of the photoconductor drum unit 20 is not limited to the configuration provided in the intermediate transfer body unit 40. The position of the photoconductor drum unit 20 may be provided on the side plate of the main body of the apparatus.

Further, in the above-described embodiment, four cartridges that can be attached to and detached from the image forming apparatus main body are used, but the number of cartridges to be used is not limited and may be appropriately set as needed.

Further, in the above-described embodiment, the laser scanner unit is used as the exposure apparatus, but the present invention is not limited to this, and for example, an LED array or the like may be used.

Further, in the above-described embodiment, a process having a photoconductor drum as a process cartridge that can be attached to and detached from the image forming apparatus main body, and a charging means, a developing means, and a cleaning means as process means acting on the photoconductor drum. The cartridge is illustrated. However, the present invention is not limited to this. In addition to the photoconductor drum, a process cartridge having any one of a charging means, a developing means, and a cleaning means may be used.

Further, in the above-described embodiment, the printer is exemplified as the image forming apparatus, but the present invention is not limited thereto. For example, it may be another image forming apparatus such as a copying machine or a facsimile apparatus, or another image forming apparatus such as a multifunction device combining these functions. Further, an image forming apparatus is exemplified in which an intermediate transfer body is used, toner images of each color are sequentially superimposed and transferred to the intermediate transfer body, and the toner images supported on the intermediate transfer body are collectively transferred to a recording medium. However, it is not limited to this. An image forming apparatus may be used in which a recording medium carrier is used and toner images of each color are sequentially superimposed and transferred onto the recording medium supported on the recording medium carrier. Similar effects can be obtained by applying the present invention to these image forming devices.

L ... Laser light P, PY, PM, PC, PK ... Process cartridge 10 ... Laser scanner unit 11 ... Laser scanner unit positioning unit 12 ... Rotation stop 13 ... Rotation stop spring 14 ... Shielding member 15 ... Image forming apparatus main body frame 16 ... Exposure section 20 ... Photoreceptor drum unit 21 ... Photoreceptor drum 30 ... Development unit 34 ... Development unit rotation stop 100 ... Image forming apparatus main body 101 ... Open / close cover 103 ... Main body positioning unit 104 ... Opening