Shaft joint and image forming device

The present invention provides a shaft joint used to detachably connect two shafts and transmit rotation from one shaft to the other, and a copier, printer, facsimile machine, etc. equipped with this shaft joint. It relates to the image forming apparatus of.

The image forming apparatus includes a photoconductor drum, a main charger arranged around the photoconductor drum, a developing device, a transfer device, a cleaning device, and the like. In such an image forming apparatus, in consideration of the interchangeability of the photoconductor drum and the like, a drum unit formed by unitizing the photoconductor drum and a main charger, a cleaning device and the like arranged around the photoconductor drum is formed in the image forming apparatus main body. Many of them are removable. In such a drum unit, when mounted on the main body of the image forming apparatus, the rotating shaft of the photoconductor drum and the rotating drive system of the main body of the image forming apparatus are known to be connected by a shaft joint ( For example, see Patent Document 1).

The photoconductor drum is rotatably supported by the drum unit. Further, the drum unit can be freely pulled out and attached to the image forming apparatus main body via the guiding means provided on the image forming apparatus main body side. A coupling member on the device side to which a rotational driving force is transmitted from a rotational driving source is rotatably supported in the image forming apparatus main body. Further, a drum-side coupling member is integrally provided at the tip of the drum shaft of the photoconductor drum.

Then, when the drum unit is inserted into the main body of the image forming apparatus, the drum-side coupling member is connected to the apparatus-side coupling member so that the rotational driving force is transmitted.

In addition, these coupling members have a convex portion (claw) that fits each other and a concave portion having a groove width wider than the convex portion, and the convex portion fits into the concave portion. Further, one of these coupling members slides in the axial direction and is urged toward the other by a spring member.

Therefore, when the drum unit is inserted into the image forming apparatus main body, if one convex portion and the other concave portion do not match, the device-side coupling member moves in the axial direction, and the convex portion becomes a portion that is not the other concave portion. It will be in a state of riding. Next, when the device-side coupling member starts to rotate, the convex portion and the concave portion are fitted by the urging force of the spring member at the position where the convex portion and the concave portion coincide with each other, and the device-side coupling member and the drum-side cup are fitted. The ring member is integrally rotatably connected. At this time, as described above, since the groove width of the concave portion is larger than the width of the convex portion, the convex portion and the concave portion fit into each other.

<patcit num="1"><text>Japanese Patent Application Laid-Open No. 6-208322 (page 4, Fig. 2)</text></patcit>

<p> In the shaft joint as disclosed in Patent Document 1 described above, a device-side coupling member is attached to the drive shaft of the drive device by forming a two-sided width shaft portion at the tip portion on the drive shaft side. A two-sided width hole that engages with the two-sided width shaft portion of the drive shaft is formed in the side coupling member, and the two-sided width hole of this device-side coupling member is fitted to the two-sided width shaft portion of the drive shaft. By doing so, many techniques have been adopted in which the drive shaft and the device-side coupling member are integrally rotated.</p><p> However, such a shaft joint needs to be attached so that the device-side coupling member can slide with respect to the drive shaft in order to smoothly connect the drum-side coupling member and the device-side coupling member. Therefore, the two-sided width shaft portion of the drive shaft and the two-sided width hole of the device-side coupling member are engaged with each other with a gap, and the device-side coupling member can slide with respect to the drive shaft. As a result, when the drive shaft is started to rotate, only the gap between the two-sided width shaft portion and the two-sided width hole causes rattling or rotation deviation, and the drive shaft rotates smoothly and accurately on the device side coupling member. There was a problem that it was not transmitted to the coupling member on the drum side.</p><p> Further, in the shaft joint as described above, when the rotation transmission torque fluctuates, rattling is likely to occur only by the gap between the two-sided width shaft portion and the two-sided width hole, which is caused by the rattling. It could cause vibration and noise.</p><p> Therefore, an object of the present invention is to provide a shaft joint capable of suppressing the occurrence of vibration, rattling, etc. when transmitting rotation from one shaft to the other shaft.</p><p> Further, the present invention smoothes the rotation of the photoconductor drum by performing rotation transmission using a shaft joint capable of suppressing vibration and rattling, and improves the image quality of the toner image transferred to the recording material. The purpose is to plan.</p>

<p> In the present invention, the first meshing member attached to the shaft end side of one shaft meshes with the second meshing member attached to the shaft end side of the other shaft, thereby engaging the one shaft with the other shaft. It relates to a shaft joint which is designed to rotate integrally. In this shaft joint, the two-sided width hole of the first meshing member is fitted into the two-sided width shaft portion formed on the shaft end side of the one shaft. Then, the first meshing member is constantly urged by the unidirectional rotation urging means in the direction opposite to the rotation direction.</p><p> The present invention also relates to an image forming apparatus characterized in that a shaft on the photoconductor side and a drive shaft are connected by a shaft joint of the above invention.</p>

<p> According to the present invention, the two-sided width shaft portion of one shaft and the two-sided width hole of the first meshing member are brought into contact with each other without a gap by the one-way rotation urging means, so that at the start of rotation of one shaft. , The rotation can be smoothly and accurately transmitted to the meshing second meshing member side without causing rattling between one shaft and the first meshing member.</p><p> Further, if the shaft joint of the present invention is used for connecting the photoconductor of the image forming apparatus and the drive shaft, the rotation on the drive shaft side can be accurately and smoothly transmitted to the photoconductor side, so that a highly accurate image can be obtained. It can be formed.</p>

Hereinafter, a shaft joint according to the best mode for carrying out the present invention and an image forming apparatus using this shaft joint will be described.

[First Embodiment]

Hereinafter, the first embodiment of the present invention will be described in detail with reference to the drawings.

1 and 2 show the shaft joint 1 according to the present embodiment. Of these, FIG. 1 is a side view schematically showing the shaft joint 1 according to the present embodiment. Further, FIG. 2 is a view seen from the direction A of FIG.

As shown in these figures, the shaft joint 1 of the present embodiment connects one shaft 3 and the other shaft 4 arranged on the same rotation axis 2 and is rotationally driven by the drive device 5. The rotation of one shaft 3 is transmitted to the other shaft 4, and the first shaft joint 6 attached to one shaft 3 side and the second shaft joint attached to the other shaft 4 side. It is composed of part 7.

Of these, the first shaft joint portion 6 is composed of a first meshing member 8 and a unidirectional rotation urging means 10 used in combination with the first meshing member 8.

The first meshing member 8 is slidably engaged with a width across flats portion 11 formed on the shaft end side of one of the shafts 3 by a width across flats 12 formed in the center of rotation thereof. It is designed to rotate integrally with one of the shafts 3. Further, the first meshing member 8 has a substantially disk shape, and a substantially arc-shaped claw 14 projecting along the circumferential direction is on the outer peripheral end side of the surface facing the other shaft 4 side. It is formed so as to project toward the shaft 4 side (second shaft joint portion 7 side) of the shaft. The claw 14 of the first meshing member 8 is adapted to mesh with the claw 15 of the second meshing member as the second shaft joint portion 7. Further, the first meshing member 8 is formed so that protrusions 16 project outward in the radial direction at positions symmetrical with respect to the circumferential direction of the outer peripheral surface thereof. The pair of protrusions 16 of the first meshing member 8 are adapted to engage with the recess 18 of the holder 17 of the unidirectional rotation urging means 10 described later.

The first meshing member 8 is prevented from coming off by a stopper member 20 such as a shaft retaining ring attached to the tip of the width across flats shaft portion 11 so as not to fall off from one of the shafts 3. , The width across flats axis portion 11 can be slid along the axial direction. Further, the two-sided width hole 12 of the first meshing member 8 is slightly smaller than the two-sided width shaft portion 11 so that the first meshing member 8 can smoothly slide along the two-sided width shaft portion 11. It is designed to engage with a gap.

The unidirectional rotation urging means 10 includes a holder 17 for accommodating the first meshing member 8 so as to be relatively rotatable and slidable, and a spring member for urging the holder 17 toward the second shaft joint portion 7. A 21 and a spring receiving member 22 that supports one end side of the spring member 21 are provided.

The holder 17 is a bottomed tubular body, and a two-sided width hole 24 that engages with the two-sided width shaft portion 11 is formed in the bottom portion 23 of the holder 17, so that the holder 17 can rotate integrally with one of the shafts 3 and can be rotated integrally. It can be slid along the width across flats axis portion 11. Further, the holder 17 is formed with a pair of recesses 18 that engage with a pair of protrusions 16 of the first meshing member 8 in a tubular portion 25 that engages with the outer periphery of the first meshing member 8 with a gap. The recess 18 of the holder 17 is formed with an inclined surface 26 that is in sliding contact with the protrusion 16 of the first meshing member 8. Then, the holder 17 is urged by the spring member 21, slides the width across flat shaft portion 11 toward the shaft end side, and presses the inclined surface 26 of the recess 18 against the protrusion 16 of the first meshing member 8. The first meshing member 8 is constantly rotated and urged in the direction opposite to the rotation direction of one of the shafts 3 by the component force F1 of the spring force F acting on the recess 18. As a result, the first meshing member 8 rotates relative to the two-sided width shaft portion 11 by the amount that eliminates the gap between the two-sided width hole 12 and the two-sided width shaft portion 11. In this way, since the two-sided width shaft portion 11 of one shaft 3 is abutted against the two-sided width surface 12a of the two-sided width hole 12 of the first meshing member 8, one shaft 3 and the first meshing member 8 rotate. It rotates integrally without rattling at the start (see Fig. 7).

The second meshing member 7 is attached to the shaft end of the other shaft 4 which is the driven shaft so as to be integrally rotatable, and the claw 14 of the first meshing member 8 is attached to the surface facing the first meshing member 8. A claw 15 that meshes with is formed. When the second meshing member 7 is set at a predetermined position, the first meshing member 8 is pressed so as to compress the spring member 21, so that the claws 14 and 15 are surely meshed with each other.

In the present embodiment, one shaft 3 side may be the driven shaft side and the other shaft 4 side may be the drive shaft side. This can also be applied to the shaft joint 1 of each embodiment described later.

Further, in the present embodiment, one shaft 3 is rotatably supported by a bearing member 28 fixed to the frame 27. Then, the first shaft joint portion 6 of the shaft joint 1 is housed in the cylindrical bearing accommodating portion 30 protruding from the side surface of the frame 27, and the claw 14 of the first meshing member 8 is exposed from the bearing accommodating portion 30. It protrudes into.

[Second Embodiment]

FIG. 3 shows the first shaft joint portion 6 of the shaft joint 1 according to the second embodiment of the present invention. As shown in FIG. 3, the first shaft joint portion 6 of the present embodiment includes a first meshing member 31 and a unidirectional rotation urging means 32 used in combination with the first meshing member 31. It is composed of.

Since the second shaft joint portion 7 constituting the shaft joint 1 is the same as that described in the first embodiment, the description thereof will be omitted. Further, in the present embodiment, the same components as those of the shaft joint 1 according to the first embodiment described above are designated by the same reference numerals, and the description that overlaps with the description of the first embodiment described above will be omitted. ..

The two-sided width hole 12 of the first meshing member 31 is integrally rotatably and slidably engaged with the two-sided width shaft portion 11 of one of the shafts 3. Further, on the back surface side of the first meshing member 31, an inclined surface 35 that abuts on the protrusion 34 of the holder 33, which will be described later, is formed.

The unidirectional rotation urging means 32 includes a substantially disk-shaped holder 33 arranged on the back surface side of the first meshing member 31, and a spring member 36 for urging the holder 33 toward the first meshing member 31. It is composed of a spring receiving member 22 that supports one end side of the spring member 21. Of these, the holder 33 is integrally rotatably and slidably engaged with the width across flats shaft portion 11 of one of the shafts 3, similarly to the first meshing member 8. Further, the holder 33 is formed with a pair of protrusions 34 abutting on the inclined surface 35 of the first meshing member 31 described above on the surface side facing the first meshing member 31. The tip of the pair of protrusions 34 of the holder 33 is formed by a smooth curved surface having a hemispherical shape, and presses a symmetrical position (symmetrical position with respect to the center of rotation) on the back surface side of the first meshing member 31. It has become like.

According to the present embodiment having such a structure, since the holder 33 is urged toward the first meshing member 31 by the spring member 21, the holder 33 and the first meshing member 31 have the protrusion 34 of the holder 33. It relatively moves in the direction of sliding down the inclined surface 35 of the first meshing member 31. That is, the first meshing member 31 is rotated by the unidirectional rotation urging means 32 in the direction opposite to the rotation direction of one of the shafts 3. As a result, as shown in FIG. 7, the first meshing member 31 rotates relative to the two-sided width shaft portion 11 by the amount that eliminates the gap between the two-sided width hole 12 and the two-sided width shaft portion 11. Move. In this way, the two-sided width shaft portion 11 of one shaft 3 and the two-sided width surface 12a of the two-sided width hole 12 of the first meshing member 31 are abutted against each other. It rotates integrally without rattling at the start of rotation (see Fig. 7).

[Third Embodiment]

4 to 6 show the first shaft joint portion 6 of the shaft joint 1 according to the third embodiment of the present invention. As shown in these figures, the first shaft joint portion 6 of the present embodiment includes the first meshing member 40 and the one-way rotation urging means 41 used in combination with the first meshing member 40. It is composed of.

Since the second shaft joint portion 7 constituting the shaft joint 1 is the same as that described in the first embodiment, the description thereof will be omitted. Further, in the present embodiment, the same components as those of the first shaft joint portion 6 according to the first embodiment described above are designated by the same reference numerals, which overlaps with the description of the first embodiment described above. The explanation is omitted.

The two-sided width hole 12 of the first meshing member 40 is integrally rotatable and slidably engaged with the two-sided width shaft portion 11 of one of the shafts 3. Further, on the back surface side of the first meshing member 40, a recess (not shown) for inserting and locking one end side of the spring member 42, which will be described later, is formed, and the inner peripheral surface of the spring member 42 is formed. A boss portion 43 that is engaged with a gap is formed in the boss portion 43.

The unidirectional rotation urging means 41 includes a coil-shaped spring member 42 arranged on the back surface side of the first meshing member 40, and a spring receiving member 45 having a claw 44 for hooking the other end side of the spring member 42. It has. A plurality of claws 44 of the spring receiving member 45 are formed along the outer peripheral end of the substantially disc-shaped spring receiving member 45, and are formed so as to stand up toward the first meshing member 40 side. Further, the spring receiving member 45 is formed with a two-sided width hole 45a that is integrally rotatable and slidably engaged with the two-sided width shaft portion 11 of one of the shafts 3, and the elastic force of the spring member 42. It is abutted against the rounded-up step portion 46 of the width across flats shaft portion 11 and its axial position is fixed.

The spring member 42 is bent so that one end side thereof stands up along the axial direction, and a first spring stopper 47 that is engaged with a recess (not shown) of the first meshing member 40 is formed. Further, the other end side of the spring member 42 is bent outward in the radial direction to form a second spring stopper 48 that is hooked on the claw 44 of the spring receiving member 45. As shown in FIG. 6, the spring member 42 having such a shape is twisted in the B direction, which is the rotation direction of one of the shafts 3, and the first spring stopper 47 is attached to the first meshing member 40. It engages with a recess (not shown) and hooks the second spring stopper 48 on the claw 44 of the spring receiving member 45. As a result, the first meshing member 40 is constantly urged by the spring force of the spring member 42 in the direction C opposite to the rotation direction B of one of the shafts 3. As a result, as shown in FIG. 7, the two-sided width surface 12a of the two-sided width hole 12 of the first meshing member 40 is in close contact with the two-sided width shaft portion 11 of one shaft 3 without a gap, and is in close contact with the one shaft 3. The first meshing member 40 rotates integrally without rattling at the start of rotation.

The spring member 42 is assembled between the first meshing member 40 and the spring receiving member 45 in a compressed state, and the first meshing member 40 is placed on the stopper member 20 side (the D direction side in FIG. 5). It is always urged.

[Fourth Embodiment]

FIG. 8 shows the first shaft joint portion 6 of the shaft joint 1 according to the fourth embodiment of the present invention. As shown in FIG. 8, the first shaft joint portion 6 of the present embodiment includes a first meshing member 50 and a unidirectional rotation urging means 51 used in combination with the meshing member 50. Has been done.

Since the second shaft joint portion 7 constituting the shaft joint 1 is the same as that described in the first embodiment, the description thereof will be omitted. Further, in the present embodiment, the same components as those of the first shaft joint portion 6 according to the first embodiment described above are designated by the same reference numerals, which overlaps with the description of the first embodiment described above. The explanation is omitted.

The two-sided width hole 12 of the first meshing member 50 is integrally rotatable and slidably engaged with the two-sided width shaft portion 11 of one of the shafts 3. Further, a pair of notches 54 that engage with the first arm portion 53 of the spring member 52, which will be described later, are formed at positions symmetrical in the circumferential direction of the outer peripheral end of the first meshing member 50. The first meshing member 50 is constantly urged by the first arm portion 53 of the spring member 52 in the direction R2 opposite to the rotation direction R1 of one of the shafts 3.

The unidirectional rotation urging means 51 is a spring member 52 formed of an elastic member. In the spring member 52, the first arm portion 53 constantly rotates and urges the first meshing member 50, and the second arm portion 55 moves the first meshing member 50 toward the stopper member 20 (left side in the drawing). Is always urged.

The spring member 52 has a substantially disk-shaped base portion 56, a pair of first arm portions 53 that stand up from a symmetrical position of the outer peripheral end of the base portion 56 in a direction substantially along the rotation axis 2, and a symmetry of the outer peripheral end of the base portion 56. It is composed of a pair of second arm portions 55 that stand up in the same direction as the standing direction of the first arm portion 53 from a position that is positioned and is substantially 90 degrees away from the first arm portion 53. The spring member 52 is engaged with the width across flats 57 formed in the base portion 56 of the spring member 52 so as to be integrally rotatable and slidable with the width across flats 11 of one of the shafts 3.

The first arm portion 53 of the spring member 52 is a plate-like body having substantially the same width, and the tip thereof is bent to form the operation portion 53a, which makes it easy for the operator's finger to be hooked on the operation portion 53a. As a result, the first arm portion 53 can be easily flexed and deformed by the operator's finger, and the operation of attaching / detaching the first arm portion 53 to / from the notch 54 becomes easy. Here, the first arm portion 53 is engaged with the notch 54 in a flexed and deformed state, and the first meshing member 50 is moved by the elastic force F1 in the direction R2 opposite to the rotation direction R1 of one shaft 3. It is always urged.

Further, as shown in FIG. 8 (c), the second arm portion 55 of the spring member 52 is formed in a vertically symmetrical shape with the rotation axis 2 as the center, and is bent and deformed toward the back surface side of the first meshing member 50. It is positioned in such a state that the first meshing member 50 is uniformly pressed with an elastic force F at a symmetrical position (symmetrical position centered on the rotation axis 2) on the back surface side. In the second arm portion 55, the portion bent into an abbreviated shape is the spring acting portion 55a, and the ridgeline portion generated by bending the tip thereof is the supporting portion 55b of the first meshing member 50.

According to the present embodiment having such a configuration, the two-sided width surface 12a of the two-sided width hole 12 of the first meshing member 50 is in close contact with the two-sided width shaft portion 11 of one shaft 3 without a gap, and one of them. The shaft 3 and the first meshing member 50 rotate integrally without rattling at the start of rotation (see FIG. 7).

Further, according to the present embodiment, the spring member 52 also has the functions of the holder 17, the spring member 21, and the spring receiving member 22 of the first embodiment described above, and the number of parts can be reduced. It is possible to reduce the product cost and reduce the size.

In the present embodiment, the spring member 52 has an example of the shape shown in FIGS. 8 (b) and 8 (c), but the shape is not limited to such a shape, and the first meshing member 50 is used as one of the shafts. It is sufficient that the first meshing member 50 can be always rotated and urged in the direction R2 opposite to the rotation direction R1 of 3 and the first meshing member 50 can be urged to the second meshing member 7 side (not shown).

Further, in the present embodiment, the spring member 52 may be formed of an elastically deformable metal, or may be formed of an elastically deformable plastic.

[Fifth Embodiment]

FIG. 9 shows the first shaft joint portion 6 of the shaft joint 1 according to the fifth embodiment of the present invention. As shown in FIG. 9, the first shaft joint portion 6 of the present embodiment includes a first meshing member 60 and a unidirectional rotation urging means 61 used in combination with the meshing member 60. Has been done.

Since the second shaft joint portion 7 constituting the shaft joint 1 is the same as that described in the first embodiment, the description thereof will be omitted. Further, in the present embodiment, the same components as those of the first shaft joint portion 6 according to the first embodiment described above are designated by the same reference numerals, which overlaps with the description of the first embodiment described above. The explanation is omitted.

The two-sided width hole 12 of the first meshing member 60 is integrally rotatable and slidably engaged with the two-sided width shaft portion 11 of one of the shafts 3. Further, at a symmetrical position in the circumferential direction on the back surface side of the first meshing member 60, an elastic piece 63 that engages with the pin 62 of the unidirectional rotation urging means 61, which will be described later, is integrally formed so as to stand up diagonally. There is. The elastic piece 63 is integrally formed on the back surface side of the first meshing member 60 when the first meshing member 60 is injection-molded, and is an elastically deformable resin piece. Since the elastic piece 63 is integrally molded in the first meshing member 60, the hole 64 for die cutting is formed so as to correspond to the forming position of the elastic piece 63.

The pin 62, in which the elastic piece 63 of the first meshing member 60 comes into contact in a flexed and deformed state, is press-fitted into the hole 65 formed in the width across flats shaft portion 11 of one of the shafts 3, and the first meshing member 60 is pressed into the hole 65. The 60 can be abutted against the stopper member 20 at the shaft end of the width across flats shaft portion 11, and the first meshing member 60 can be urged in the direction R2 opposite to the rotation direction R1 of one shaft 3. As described above, the elastic piece 63 of the first meshing member 60 is arranged at a position where it can be flexed and deformed. The arrow F in FIG. 9B is an elastic force generated by bending and deforming an elastic piece 63 that is inclined at an angle, and is an elastic force that presses the first meshing member 60 toward the stopper member 20 side. Further, the arrow F1 in FIG. 9B is an elastic force generated by bending and deforming an elastic piece 63 inclined at an angle, and is an elastic force for urging the first meshing member 60 in the R2 direction. Here, the elastic piece 63 and the pin 62 constitute the unidirectional rotation urging means 61.

According to the present embodiment having such a configuration, as shown in FIG. 7, the width across flats 12a of the width across flats 12 of the first meshing member 60 becomes the width across flats 11 of one of the shafts 3. Since they are in close contact with each other without any gaps, the same effect as that of the fourth embodiment can be obtained. Moreover, according to the present embodiment, the structure can be simplified as compared with the fourth embodiment.

In the present embodiment, the embodiment in which the elastic piece 63 is integrally formed with the first meshing member 60 by injection molding is illustrated, but the metal plate on which the elastic piece 63 is formed and the resin first meshing member 60 are inserted. It may be integrated by molding.

[Outline configuration of image forming apparatus]

FIG. 10 is a schematic configuration diagram schematically showing an image forming apparatus 100 using any of the shaft joints 1 of each of the above-described embodiments. The image forming apparatus 100 is sent out from the paper feeding unit 103 that sends out the recording sheet P as a recording material such as printing paper and plastic film from the paper feeding tray 102 into the image forming apparatus main body 101, and from the paper feeding unit 103. A sheet transport section 104 that transports the recorded sheet P along the sheet transport path R, an image forming section 105 that forms an image on the recording sheet P conveyed by the sheet transport section 104, and a recording sheet by the image forming section 105. It is roughly composed of a fixing unit 106 for fixing the toner image formed on P and a sheet discharging unit 108 for discharging the recording sheet P on which the toner image is fixed by the fixing unit 106 to the paper ejection tray 107. ..

As shown in FIG. 10, the image forming unit 105 includes a drum unit 110 inserted along a guide rail (not shown) provided in the image forming apparatus main body 101 (along the alternate long and short dash line s), and a transfer roller as a transfer unit. It is configured with 111. The transfer roller 111 comes into contact with a drum-type photoconductor (hereinafter, referred to as a photoconductor drum) 112 while rotating.

Further, as shown in FIG. 10, the drum unit 110 irradiates the photoconductor drum 112, a charger (not shown) arranged around the photoconductor drum 112, and a position on the photoconductor drum 112 downstream of the charger in the rotational direction with laser irradiation. An exposure device (not shown), a developer 113 that supplies toner to an electrostatic latent image formed on the surface of the photoconductor drum 112 to form a toner image, and a toner container 114 that is detachably attached to the developer 113. A cleaning device 115 that removes the toner remaining on the surface of the photoconductor drum 112 that has passed through the transfer roller 111 provided on the image forming apparatus main body 101 side, and a waste toner that accumulates the toner collected by the cleaning device 115. It is roughly configured with a box 116.

Here, when the drum unit 110 is mounted at a predetermined position in the image forming apparatus main body 101 along the guide rail (s), the second drum unit 110 is mounted on the end of the other shaft 4 which is the shaft of the photoconductor drum 112. The second meshing member 7 as the shaft joint portion of the first shaft joint portion 6 attached to one shaft (drive shaft) 3 rotatably supported by the frame 27 on the image forming apparatus main body 101 side. It meshes with the first meshing member (8,31,40,50,60) (see Fig. 10, Fig. 1, Fig. 3, Fig. 4, Fig. 8, Fig. 9). As a result, the drive device 5 on the image forming apparatus main body 101 side and the photoconductor drum 112 are connected via the shaft joint 1.

According to the image forming apparatus 100 of the present embodiment as described above, as shown in FIG. 7, between one shaft 3 on the driving side and the first meshing member (8,31,40,50,60). Since no rattling occurs, the rotation of the photoconductor drum 112 is smoothly started.

Further, according to the image forming apparatus of the present embodiment, for example, the vibration and rattling of the photoconductor drum 112 due to the external action of the developing device 113, the transfer roller 111, the cleaning device 115, the recording sheet P, etc. Since it can be suppressed by the urging force of the unidirectional rotation urging means (10,32,41,51,61) of the joint 1, the toner that is transferred to the recording sheet P by smoothing the rotation of the photoconductor drum 112 It is possible to improve the image quality of the image.

The present invention can be widely applied to an image forming apparatus such as a copier, a facsimile, a printer, or a multifunction device having these functions. Further, the shaft joint according to the present invention is not limited to the image forming apparatus, and can be widely applied to power transmission between two shafts of various precision machines, automobile parts, industrial machines and the like.

<figref num="1">It is a side view which shows typically the shaft joint which concerns on 1st Embodiment of this invention.</figref><figref num="2">It is a view seen from the A direction of FIG. 1, and is the front view of the 1st shaft joint part.</figref><figref num="3">It is a side view which shows typically the 1st shaft joint part of the shaft joint which concerns on 2nd Embodiment of this invention.</figref><figref num="4">It is a side view which shows typically the 1st shaft joint part of the shaft joint which concerns on 3rd Embodiment of this invention in the cross section of a part (the 1st meshing member).</figref><figref num="5">It is an exploded perspective view of the 1st shaft joint part which concerns on 3rd Embodiment of this invention.</figref><figref num="6">It is a front view of the spring member which concerns on 3rd Embodiment of this invention.</figref><figref num="7">It is a figure which shows the engaging state between the width across flats shaft portion of one shaft, and the width across flats hole of the 1st meshing member.</figref><figref num="8">It is a side view which shows typically the 1st shaft joint part of the shaft joint which concerns on 4th Embodiment of this invention. (a) is a front view of the first meshing member, (b) is a front view of the spring member, and (c) is a side view schematically showing the first shaft joint portion.</figref><figref num="9">It is a side view which shows typically the 1st shaft joint part of the shaft joint which concerns on 5th Embodiment of this invention. (a) is a front view of the first meshing member, and (b) is a side view schematically showing the first shaft joint portion.</figref><figref num="10">It is a block diagram which shows typically the image forming apparatus which is configured to use any of the shaft joints which concerns on 1st to 5th Embodiment of this invention.</figref>

Code description

1 ...... Shaft joint, 3 ...... One shaft (drive shaft), 4 ...... The other shaft, 7 ...... 2nd meshing member (2nd Shaft joint part), 8,31,40,50,60 ...... 1st meshing member, 10,32,41,51,61 ...... One-way rotation urging means, 11 ...... Width axis part, 12 ...... Width hole, 100 ...... Image forming device, 112 ...... Photoreceptor drum (photoreceptor)