JP2011095711A - Process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process cartridge that enables a rotor, which rotates by receiving a drive force from a photoreceptor drum, to bias the photoreceptor drum with uniform force. <P>SOLUTION: A distance between the shaft of a drum gear 68 and the shaft of a cleaning gear 70 is fixed by fixing portions 32A and 32B disposed in contact with both ends of a cleaning gear 70. Thus, biasing force applied to the photoreceptor drum 5 by a cleaning roller 41 connected to the cleaning gear 70 is prevented from becoming non-uniform. Further, the cleaning gear 70 and the cleaning roller 41 are connected by an oldham shaft coupling 60. Thus, even if eccentricity occurs in rotation of the cleaning roller 41 due to the effect of the tolerance of the cleaning roller itself, the oldham shaft coupling 60 absorbs the deviation, thereby stabilizing the biasing force applied to the photoreceptor drum 5 by the cleaning roller 41, without especially bringing a fixed wall or the like into contact with the cleaning roller 41. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a process cartridge mounted on an image forming apparatus.

  2. Description of the Related Art Conventionally, in a process cartridge configured to be detachable from a laser printer as an example of an image forming apparatus to which an electrophotographic system is applied, cleaning for removing foreign matters such as residual toner adhering to the peripheral surface of a photosensitive drum The thing provided with the roller is known (refer patent document 1).

  This cleaning roller is provided with a cleaning gear at one end thereof. On the other hand, a drum gear is provided at one end of the photosensitive drum. The cleaning gear and the drum gear are engaged with each other, and the driving force input to the drum gear is transmitted to the cleaning gear. Thereby, the rotation of the cleaning roller is achieved. The cleaning roller is urged against the surface of the photosensitive drum by an urging member such as a spring. At this time, the cleaning roller rotates so as to move in the same direction as the movement direction of the circumferential surface of the photosensitive drum, and collects foreign matter on the circumferential surface of the photosensitive drum.

JP 2004-109319 A

  However, in the above configuration, the following phenomenon may occur. That is, as shown in FIG. 8A, in the configuration in which the drum gear 168 and the cleaning gear 170 are meshed with each other, the drum gear 168 and the cleaning gear 170 may be affected by environmental changes, tolerances of the cleaning roller 141 itself, and the like. The distance between may change. Then, the rotation of the cleaning roller 141 becomes unstable.

  When the rotation of the cleaning roller 141 becomes unstable, the force (in the direction of the arrow) that urges the cleaning roller 141 toward the photosensitive drum 105 is not uniform in the axial direction (left and right direction in the figure) of the cleaning roller 141. Then, there is a possibility that the deposits on the photosensitive drum 105 will not be recovered well.

  Therefore, as a configuration for stabilizing the distance between the cleaning gear 170 and the drum gear 168, as shown in FIG. 8B, a fixed wall 132A is formed in a frame (not shown) and is brought into contact with the shaft center portion 174 of the cleaning gear 170. It is possible. Accordingly, the movement of the cleaning gear 170 can be restricted and fixed at a certain position.

  However, when the fixed wall 132A is brought into contact with the cleaning gear 170, the cleaning roller 141 biases the photosensitive drum 105 on the side where the fixed wall 132A is in contact with the cleaning roller 141 in the axial direction and on the side where the fixed wall 132A is not in contact. There will be a difference in the urging force. Therefore, it is difficult to collect the deposits on the photosensitive drum 105 well.

Further, as shown in FIG. 8C, the fixed wall 132A is brought into contact with the shaft center part 174 of the cleaning gear 170, and another fixed wall 132B is placed on the opposite side of the fixed wall 132A with the cleaning roller 141 interposed therebetween. It is conceivable to make them abut. In this case, a difference in urging force that urges the photosensitive drum 105 by the cleaning roller 141 is less likely to occur in the axial direction.

  However, due to the tolerance of the diameter of the cleaning roller 141, the fixed walls 132A and 132B may or may not contact the cleaning gear 170 or the cleaning roller 141. Therefore, it is difficult to always urge the cleaning roller 141 to the photosensitive drum 105 with a uniform urging force.

  The above-mentioned problem is not limited to the relationship between the photosensitive drum and the cleaning roller, but also applies to the relationship between the photosensitive drum and a rotating body that receives a driving force from the photosensitive drum, such as a transfer roller and a charging roller.

  In view of the above problems, an object of the present invention is to provide a process cartridge capable of urging a rotating body that receives a driving force from a photosensitive drum to rotate with a uniform force against the photosensitive drum.

  In order to solve the above problems, a process cartridge according to the present invention includes a photosensitive drum having a developer image formed on a surface thereof, and is configured to be attachable to an image forming apparatus. A rotating body that contacts the surface of the drum; a frame that holds the rotating body; a first gear that is provided on one end side in the axial direction of the photosensitive drum and that receives a driving force from the image forming apparatus main body; and the first gear; A second gear having a gear main body portion to be engaged, and shaft center portions formed at both ends of the gear main body portion, an Oldham shaft joint for connecting the rotating body and the shaft center portion, and a second gear A fixing portion is provided that contacts the shaft center portion and fixes an inter-axis distance between the first gear and the second gear.

  Moreover, the said fixing | fixed part may be provided with the control surface which controls that a 2nd gear moves to the direction into which the rotational drive force was input from said 1st gear.

  Further, the fixing portion may be formed on a frame that holds the rotating body and abuts on both ends of the shaft center portion of the second gear.

  In addition, a first holding portion that rotatably holds the photosensitive drum and a second holding portion that rotatably holds the shaft center portion of the second gear are provided at one axial end of the photosensitive drum. A holding member may be provided.

  Moreover, you may make it have the sheet metal which positions the said holding member in the said axial direction edge part.

  The rotating body may be a cleaning roller that cleans deposits on the peripheral surface of the photosensitive drum.

  According to the process cartridge of the present invention, even if the rotation of the rotating body is eccentric due to the tolerance of the rotating body itself, the Oldham shaft coupling absorbs the deviation. Therefore, the urging force of the rotating body against the photosensitive drum can be stabilized. At this time, it is not necessary to abut the fixed wall directly on the rotating body. Furthermore, since the inter-axis distance between the first gear and the second gear is fixed by bringing the fixing portion into contact with the shaft center portion of the second gear, the rotating body connected to the second gear is attached to the photosensitive drum. It is possible to prevent the power from becoming uneven.

In addition, if the fixed portion has a restriction surface that restricts the second gear from moving in the direction in which the rotational driving force is input from the first gear, the second gear is moved by the driving force received from the first gear. Can be prevented.

  Further, if the fixed portion is formed on the frame for holding the rotating portion and is in contact with both ends of the shaft center portion of the second gear, the distance between the shafts of the first gear and the second gear can be more stably increased. It becomes possible to stabilize.

  In addition, by holding the photosensitive drum and the axial center of the second gear with the same holding member, the distance between the first gear and the second gear held by the photosensitive drum can be more accurately maintained, and the shaft The photosensitive drum and the rotating body can be brought into contact with each other with a uniform force in the direction.

  Further, by positioning the holding member with respect to the sheet metal, the photosensitive drum and the rotating body can be held with high accuracy.

  Further, if the rotating body is a cleaning roller that cleans deposits on the peripheral surface of the photosensitive drum, the biasing force when the cleaning roller biases the photosensitive drum can be made uniform in the axial direction. Deposits on the photosensitive drum can be cleaned well.

It is a sectional side view showing one embodiment of a printer. It is principal part sectional drawing of a photoconductor unit. FIG. 3 is a cross-sectional view of a main part when the photoconductor unit is viewed from above. FIG. 5 is a side sectional view showing a bearing member that supports a photosensitive drum and a cleaning roller in the photosensitive unit. FIG. 4 is an enlarged view in which one end side of the photosensitive unit in FIG. 3 is enlarged. It is the perspective view which decomposed | disassembled and showed the Oldham shaft coupling. It is CC sectional drawing of FIG. It is a reference diagram regarding a drive transmission mechanism of a photosensitive drum and a cleaning roller. FIG. 6 is a side view of a photoconductor unit, showing a photoconductor unit according to a second embodiment. FIG. 5 is a front view of a photoconductor unit, showing a photoconductor unit according to a second embodiment. It is drawing showing the photoconductor unit which concerns on 2nd embodiment, Comprising: The AA cross section of (a) is represented. It is a perspective view of a 1st drum bearing. FIG. 3 is a perspective view of the photosensitive unit, and shows one end side (first drum bearing side) of the photosensitive drum.

(First embodiment)
[Schematic configuration of printer]
Embodiments of the present invention will be described with reference to the drawings. In addition, when referring to a direction, the illustrated direction arrow is referred to (the same applies to other drawings). The printer 1 is a tandem color laser printer. The printer 1 includes a main body casing 2. A front cover 3 is provided on the front surface of the main casing 2 so as to be openable and closable.

  A tandem type photoreceptor unit 4 as an example of the process cartridge of the present invention is provided in the main casing 2. The tandem photoconductor unit 4 is detachable from the inside of the main body casing 2 through an attachment / detachment opening formed on the front surface of the main body casing 2 with the front cover 3 being opened.

  In the tandem type photoreceptor unit 4, four photosensitive drums 5 are arranged in parallel along the front-rear direction in a rotatable state. Each photosensitive drum 5 is provided with a scorotron charger 6 and a developing roller 7 facing each other.

  The tandem photoconductor unit 4 includes a unit frame 20 that forms an outline thereof, four photoconductor units 21 each including the above-described photosensitive drum 5, and the above-described four developing cartridges 8.

  The unit frame 20 has a frame shape having a substantially rectangular shape in the longitudinal direction when viewed from the vertical direction, and is open to both the upper and lower sides. The four photoconductor units 21 are supported by the unit frame 20 at substantially equal intervals. Each photoconductor unit 21 corresponds to one of the developing cartridges 8 of each color.

  On each photosensitive drum 5, a developing cartridge 8 that holds a developing roller 7 and stores toner (developer) of each color is disposed adjacently from above. Four developing cartridges 8 are provided in the same manner as the photosensitive drum 5, and are detachably attached to the tandem photosensitive unit 4 in a state of being arranged in parallel along the front-rear direction.

  Each developing cartridge 8 is attached to and detached from the unit frame 20 from above in a state where the tandem photosensitive unit 4 is slid from the main casing 2. In each developing cartridge 8, toner corresponding to each color is carried on the outer peripheral surface (surface) of the developing roller 7. The surface of the developing roller 7 is in contact with the outer peripheral surface (surface) of the corresponding photosensitive drum 5 from the front upper side.

  The outer peripheral surface of each photosensitive drum 5 is uniformly charged by the charger 6 and then exposed by a laser beam (see the broken arrow in FIG. 1) emitted from the scanner unit 9 provided on the upper portion of the main casing 2. Is done. Thereby, an electrostatic latent image based on the image data is formed on the outer peripheral surface of each photosensitive drum 5. The electrostatic latent image on each photosensitive drum 5 is visualized by toner carried on the outer peripheral surface of the developing roller 7 corresponding to each photosensitive drum 5, and each color toner image is displayed on the outer peripheral surface of each photosensitive drum 5. (Developer image) is formed.

  At the bottom of the main casing 2, a paper feed cassette 10 that stores the paper S is disposed. The paper S accommodated in the paper feed cassette 10 is conveyed to the upper surface of the belt 11 by various rollers, and further passes between the belt 11 and each photosensitive drum 5 sequentially as the belt 11 travels. The toner image on the outer peripheral surface of the photosensitive drum 5 is transferred to the paper S by the transfer bias applied to the transfer roller 12 when facing (contacting) the paper S. The toner that is not transferred to the sheet S and adheres to the surface of the photosensitive drum 5 is collected by the cleaning roller 41 as an example of the rotating body of the present invention disposed while being urged by the photosensitive drum 5.

  A fixing device 13 is provided downstream of the belt 11 in the transport direction of the paper S. The sheet S on which the toner image is transferred is fixed on the sheet S by the fixing device 13. The sheet S on which the toner image is fixed is discharged to a discharge tray 14 on the upper surface of the main casing 2 by various rollers.

  As shown in FIG. 2, each photoconductor unit 21 includes a single photoconductive drum 5 and a subunit 19 that is opposed to the photoconductive drum 5 from the upper rear side. The subunit 19 includes a frame 35, a charger 6, and a cleaning roller 41. The frame 35 holds the charger 6 and the cleaning roller 41.

[Cleaning roller and photosensitive drum drive mechanism]
Next, the driving mechanism for the cleaning roller 41 and the photosensitive drum 5 will be described. As shown in FIG. 3, the photosensitive drum 5 has a cylindrical shape, and includes a drum gear 68 as an example of the first gear of the present invention on the circumferential surface on one end side in the axial direction. The drum gear 68 has gear teeth on its outer peripheral surface.

  The photosensitive drum 5 receives a rotational driving force from a driving input unit (not shown) provided in the main casing 2 and rotates in the direction of the arrow (counterclockwise) in FIG. The drive input unit is a known drive mechanism such as a gear mechanism that meshes with the drum gear 68 to input a driving force, or a coupling mechanism that inputs the rotational driving force by connecting to the photosensitive drum 5 from the axial direction of the photosensitive drum 5. Can take.

  The frame 35 holds a pair of bearing members 50 and a pair of coil springs 52. Further, a first fixing portion 32 </ b> A and a second fixing portion 32 </ b> B formed in a rib shape in the frame 35 are formed at the end of the frame 35 on the drum gear 68 side.

  As shown in FIG. 4, each of the pair of bearing members 50 has a substantially cylindrical shape whose central axis extends parallel to the axial direction (width direction) of the photosensitive drum 5. The bearing member 50 has a convex portion 62 projecting to the rear side, and a long coil spring 52 is externally fitted to the convex portion 62. One end of the coil spring 52 is attached to the frame 35 and the other end is externally fitted to the convex portion 62 of the bearing member 50. As a result, the bearing member 50 receives a biasing force from the coil spring 52.

  Both ends of the cleaning roller 41 are held by the bearing member 50 thus configured (see FIG. 3). The cleaning roller 41 is urged toward the photosensitive drum 5 while being held with respect to the frame 35. At this time, the direction in which the cleaning roller 41 is urged is the same direction as the line O <b> 1 connecting the axes of the cleaning roller 41 and the photosensitive drum 5.

  The cleaning roller 41 is a cylindrical member, and includes a shaft portion 42 and a foamed body (for example, sponge) coated on the outer peripheral surface excluding both ends of the shaft portion 42. The cleaning roller 41 extends in a direction parallel to the axial center direction of the photosensitive drum 5 and is disposed so that the sponge portion contacts the surface of the photosensitive drum 5. Further, the end of the cleaning roller 41 on the drum gear 68 side is connected to a cleaning gear 70 as an example of the second gear of the present invention via an Oldham coupling 60.

  As shown in FIG. 5, the cleaning gear 70 extends from both side surfaces of the gear main body 72 with a cylindrical gear main body 72 having gear teeth on its outer peripheral surface, and the same rotation axis as that of the gear main body 72. And a cylindrical shaft center portion 74 formed in the shape. The outer diameter of the shaft center portion 74 is smaller than the outer diameter of the gear main body portion 72. The gear main body 72 is engaged with the drum gear 68 to transmit the rotational driving force from the photosensitive drum 5.

  As shown in FIG. 6, the Oldham shaft coupling 60 projects from one end of a coupling member 66, a roller-side convex portion 62 projecting from the end portion of the shaft portion 42 of the cleaning roller 41, and a shaft center portion 74 of the cleaning gear 70. It is comprised from the gear side convex part 64 formed so that. The joint member 66 is connected to the roller side convex portion 62 and the gear side convex portion 64 on both side surfaces thereof.

Specifically, the joint member 66 is formed with grooves 65 and 67 that are orthogonal to each other on both surfaces thereof. And the roller side convex part 62 and the gear side convex part 64 are fitted with respect to the groove parts 65 and 67, respectively. The convex portions 62 and 64 are slidable along the groove portions 65 and 67 while being fitted in the groove portions 65 and 67. As a result, the cleaning roller 41 and the cleaning gear 70 are connected via the joint member 66. At this time, the shaft centers of the cleaning roller 41 and the cleaning gear 70 are coupled so as to be parallel to each other.

  As shown in FIG. 7, the first fixed portion 32 </ b> A and the second fixed portion 32 </ b> B extend so as to be orthogonal to the axial direction of the axial center portion 74 of the cleaning gear 70. The first fixed portion 32A and the second fixed portion 32B are formed on one end side of the frame 35, that is, on the drum gear 68 side, and are not formed on the other end side. The first fixing portion 32 </ b> A and the second fixing portion 32 </ b> B are in contact with the peripheral surfaces of both shaft center portions 74 so as to sandwich the gear main body portion 72 of the cleaning gear 70.

  The first fixing portion 32 </ b> A includes a fixed surface 31 constituted by a plane and a regulating surface 33 extending from the fixed surface 31 in the vertical direction. The first fixed portion 32A is in contact with the axial center portion 74 of the cleaning gear 70 at two locations.

  The fixed surface 31 is disposed so as to receive the cleaning gear 70 on the opposite side of the photosensitive drum 5 with the cleaning roller 41 interposed therebetween. Specifically, the fixed surface 31 extends so as to intersect with a line O1 connecting the cleaning roller 41 (cleaning gear 70) and the shaft centers of the photosensitive drum 5. The movement of the cleaning gear 70 is restricted so that the inter-axis distance L between the drum gear 68 and the cleaning gear 70 does not change when the fixed surface 31 comes into contact with the shaft center portion 74 of the cleaning gear 70.

  Further, like the fixed surface 31, the restricting surface 33 is mainly composed of a flat surface. The restricting surface 33 is in contact with the axial center portion 74 of the cleaning gear 70. As a result, the cleaning gear 70 is restricted from moving under the driving force of the drum gear 68. Specifically, the cleaning gear 70 receives pressure in a direction (pressure angle direction O3) inclined by a predetermined angle (20 degrees in the present embodiment) with respect to the tangential direction O2 of the both by engagement with the drum gear 68.

  On the other hand, the restricting surface 33 extends in a direction perpendicular to the direction O3 of the pressure received by the cleaning gear 70 from the drum gear 68 and is in contact with the axial center portion 74 of the cleaning gear 70. As a result, the restriction surface 33 restricts the position of the axial center portion 74 of the cleaning gear 70 so that the cleaning gear 70 does not move in the direction of receiving pressure.

  The second fixing portion 32B is in contact with the shaft center portion 74 of the cleaning gear 70 on the opposite side of the first fixing portion 32A with the gear main body portion 72 of the cleaning gear 70 interposed therebetween. Other configurations are the same as those of the first fixing portion 32A.

  The photoreceptor unit 21 configured as described above has the following operational effects. That is, the fixing portions 32 </ b> A and 32 </ b> B are in contact with the shaft center portions 74 provided at both ends of the cleaning gear 70. Accordingly, the inter-axis distance between the drum gear 68 and the cleaning gear 70 is fixed. As a result, when the cleaning roller 41 connected to the cleaning gear 70 urges the photosensitive drum 5, it is possible to prevent the urging force from becoming uneven.

  Further, in this embodiment, the cleaning gear 70 and the cleaning roller 41 are connected by the Oldham shaft joint 60. Thus, even if the cleaning roller 41 is eccentric due to the tolerance of the cleaning roller 41 itself, the Oldham shaft coupling 60 absorbs the deviation. Therefore, the urging force of the cleaning roller 41 against the photosensitive drum 5 can be stabilized. At this time, it is not necessary to bring a fixed wall or the like into direct contact with the cleaning roller 41.

Further, the first fixing portion 32 </ b> A and the second fixing portion 32 </ b> B have a regulation surface 33. The regulation surface 33 is
The movement of the rotational driving force input from the drum gear 68 in the input direction is restricted. Therefore, the regulating surface 33 can prevent the cleaning gear 70 from moving due to the driving force received from the drum gear 68, and can further stabilize the positional relationship between the cleaning gear 70 and the drum gear 68.

(Second embodiment)
Next, another embodiment relating to the present invention will be described. Note that, in the description of the second embodiment, the same reference numerals as those in the first embodiment are assigned to items that are the same as those described in the first embodiment, and detailed description thereof is omitted. This embodiment is different from the previous embodiment in that it includes a drum bearing 210 for supporting the photosensitive drum 5 and metal side plates 220A and 220B as shown in FIG.

  The tandem type photoconductor unit 104 includes the above-described four photoconductor units 21 and the above-described four developing cartridges 8 in a unit frame 20 that forms an outline thereof. Further, as shown in FIGS. 9A and 9B, the tandem type photoreceptor unit 104 is provided with a pair of first side plates 220A and second side plates 220B at both ends in the axial direction of the photosensitive drum 5. Further, the tandem photoconductor unit 104 includes a first drum bearing 210 </ b> A and a second drum bearing 210 </ b> B for holding each photoconductor unit 21 on each side plate 220. Among these, the first drum bearing 210A plays a role as an example of the holding member of the present invention. The first drum bearing 210A and the second drum bearing 210B are provided in pairs for each photosensitive drum.

  As shown in FIG. 9C, the first drum bearing 210A is made of a resin material and is formed in a cylindrical shape, the first cylindrical portion 201 as an example of the first holding portion of the present invention, and the first cylinder A disc-shaped first flange 202 formed on one side of the portion 201, a second cylindrical portion 203 as an example of a second holding portion of the present invention, and a second flange 204 are provided. The second drum bearing 210B is made of a resin material and has a first cylindrical portion 201 formed in a cylindrical shape, and a disc-shaped first flange portion 202 formed on one side of the first cylindrical portion 201. It has.

  More specifically, the first cylindrical portion 201 has substantially the same outer diameter as the inner peripheral surface of a drum holding hole 221 (described later) formed in the side plate 220, and the outer peripheral surface of the flange portion 38 at the end of the photosensitive drum 5. Have approximately the same inner diameter. The first flange portion 202 has a larger outer diameter than the first cylindrical portion 201.

  As shown in FIG. 10, the first drum bearing 210 </ b> A is provided with a second cylindrical portion 203 for holding the cleaning gear 70 at a position adjacent to the first cylindrical portion 201. The second cylindrical portion 203 has a smaller diameter than the first cylindrical portion 201 and extends in the same direction as the first cylindrical portion 201. The second cylindrical portion 203 has an inner diameter that is substantially the same as the outer shape of the axial center portion 74 of the cleaning gear 70. On one side of the second cylindrical portion 203, a second flange portion 204 having an outer periphery larger than the outer periphery of the second cylindrical portion 203 is formed. The 1st collar part 202 and the 2nd collar part 204 are continuously formed on the same flat plate.

Furthermore, the first collar 202 has a claw 205 for locking to the first side plate 220A. The claw portions 205 are arranged in pairs so as to sandwich the first cylindrical portion 201 in the radial direction. The claw portion 205 extends in the radial direction from the edge portion of the first flange portion 202, and is further bent toward the extending direction of the first cylindrical portion 201, that is, the axial direction of the photosensitive drum 5. The claw portion 205 holds the drum bearings 210A and 210B on the first side plate 220A by sandwiching the edge of the first side plate 220A at the bent portion. Each claw portion 205 is disposed so as to face the photosensitive member unit 21 in the vertical direction. More specifically, the claw portions 205 are opposed to each other so as to intersect in a direction substantially orthogonal to the direction in which the first cylindrical portion 201 and the second cylindrical portion 203 are adjacent to each other (see FIG. 9A).

  Each of the side plates 220A and 220B is manufactured by pressing a metal plate, and is formed in a substantially elongated rectangular plate shape that extends in the direction in which the four photosensitive drums 5 are arranged. The first side plate 220 </ b> A and the second side plate 220 </ b> B are arranged to face each other so as to sandwich the photosensitive drum 5 in the axial direction of the photosensitive drum 5.

  As shown in FIG. 9C, a circular drum holding hole 221 for inserting and holding the first drum bearing 210A or the second drum bearing 210B is formed in the first side plate 220A and the second side plate 220B. Yes. The drum holding holes 221 are formed at regular intervals in the alignment direction of the photosensitive drums 5 in the side plates 220A and 220B.

  Further, a first side plate 220A that holds the photosensitive drum 5 on the side having the drum gear 68 is formed with a through hole 222 through which the first drum bearing 210A and the cleaning gear 70 can be inserted. Furthermore, the edge part of the 1st side board 220A and the 2nd side board 220B is provided with the groove part 223 formed in order to receive the nail | claw part 205 formed in the 1st drum bearing 210A and the 2nd drum bearing 210B mentioned above. (See also FIG. 11).

  In the tandem photoconductor unit 104 configured as described above, as shown in FIG. 11, the photoconductor drum 5 is disposed so as to be sandwiched between the both side plates 220A and 220B, and the flange portions 38 at both ends in the axial direction are formed as the first. The drum holding holes 221 of the first side plate 220A and the second side plate 220B are inserted. Bearing members 5 provided at both ends of the cleaning roller 41 are biased toward the photosensitive drum 5 by a coil spring 52.

  The cleaning gear 70 connected to one end side of the cleaning roller 41 via the Oldham shaft joint 60 causes the shaft center portion 74 on the side connected to the Oldham shaft joint 60 to abut on the second fixed portion 32 </ b> B of the frame 35. Yes. Further, the axial center portion 74 opposite to the side connected to the Oldham shaft coupling 60 extends outward in the axial direction of the cleaning roller 41, passes through the frame 35 and the through hole 222, and is exposed to the outside of the first side plate 220 </ b> A. (See FIG. 9C).

  A first drum bearing 210A is assembled to the flange portion 38 on the drum gear 68 side of the photosensitive drum 5 inserted through the drum holding hole 221 of the first side plate 220A. Specifically, the first cylindrical portion 201 of the first drum bearing 210A is lightly press-fitted between the outer peripheral surface of the flange portion 38 exposed to the outside in the drum axial direction from the drum holding hole 221 and the drum holding hole 221. (See also FIG. 9 (c)). The flange portion 38 passes through the first cylindrical portion 201 and is exposed to the outside from the first flange portion 202.

  Further, in a state where the first drum bearing 210A is supported with respect to the side plate 220, the shaft center portion 74 that penetrates the through hole 222 and exposes the end portion to the outside of the first side plate 220A is a second cylindrical portion. 203. Specifically, the first drum bearing 210 </ b> A holds the cleaning gear 70 by holding the shaft portion 74 rotatably with respect to the second cylindrical portion 203. That is, the flange portion 38 of the photosensitive drum 5 is rotatably held by the first cylindrical portion 201 of the first drum bearing 210A, while the axial center portion 74 of the cleaning gear 70 is the second cylinder of the first drum bearing 210A. Since the portion 203 is rotatably held, the distance between the drum gear 68 and the cleaning gear 70 is kept constant.

Then, as shown in FIG. 11, the claw portion 205 extending radially outward from the first flange portion 202 bites into the edge portion of the first side plate 220A, so that the photosensitive unit 21 is positioned with respect to the first side plate 220A. . Accordingly, the first drum bearing 210A is supported so as not to rotate with respect to the first side plate 220A, and the flange portion 38 is supported so as to be rotatable with respect to the first drum bearing 210A.

  The first cylindrical portion 201 of the second drum bearing 210B is lightly press-fitted between the outer peripheral surface of the flange portion 38 inserted into the drum holding hole 221 of the second side plate 220B opposite to the drum gear 68 and the drum holding hole 221. Is done. More specifically, first, the second drum bearing 210 </ b> B is lightly press-fitted into the flange portion 38. Then, the end of the second drum bearing 210B is lightly press-fitted into the drum holding hole 221 of the second side plate 220B. The claw portion 205 of the second drum bearing 210B is locked to the side plate 220. As a result, the flange portion 38 of the photosensitive drum 5 is held by the second side plate 220B.

  The side plates 220A and 220B holding the photosensitive drum 5 are screwed to the unit frame 20 by screws (not shown) from the outside.

  In this manner, the drum bearings 210A and 210B are lightly press-fitted into both ends of the photosensitive drum 5, and the drum bearings 210A and 210B are lightly press-fitted into the side plates 220A and 220B, so that the photosensitive drum 5 has the first side plate 220A and the first side plate 220A. It is held against the second side plate 220B. At this time, since the first drum bearing 210A integrally holds the flange portion 38 on the drum gear 68 side and the shaft center portion 74 of the cleaning gear 70, the inter-shaft distance between the drum gear 68 and the cleaning gear 70 is accurately maintained. The photosensitive drum 5 and the cleaning roller 41 can be brought into contact with each other with a uniform force in the axial direction.

  In addition, by positioning the drum bearings 210A and 210B with respect to the metal side plates 220A and 220B, the photosensitive drum 5 and the cleaning roller 41 can be accurately held.

  In the present embodiment, the present invention has been described by exemplifying the cleaning roller as the rotating body, but the present invention is not limited to the present embodiment. For example, the present invention may be applied to a driving mechanism such as a transfer roller or a charging roller that is disposed to face the photosensitive drum.

  In this embodiment, the frame 35 is configured to hold the charger 6 and the cleaning roller 41. However, the charger 6 and the cleaning roller 41 are held by different frames. It may be configured. That is, each may be unitized. For example, the cleaning roller 41 may be integrally held by the frame 35 together with the bearing member 50 and the coil spring 52 as a cleaning unit.

  Further, the tandem type photoconductor unit is exemplified as the process cartridge according to the present invention. However, various modifications such as applying the present invention to a photoconductor cartridge in which a developing cartridge is detachable in a monochrome printer, for example. Is possible.

DESCRIPTION OF SYMBOLS 1 Printer 2 Main body casing 4 Tandem type photoconductor unit 5 Photosensitive drum 21 Photoconductor unit 32A, 32B Fixing part 33 Control surface 35 Frame 41 Cleaning roller 60 Oldham shaft coupling 68 Drum gear 70 Cleaning gear

Claims (6)

A process cartridge comprising a photosensitive drum on which a developer image is formed and configured to be attachable to an image forming apparatus,
A rotating body that contacts the surface of the photosensitive drum;
A first gear provided on one end side in the axial direction of the photosensitive drum and receiving a driving force from the image forming apparatus main body;
A second gear having a gear main body that meshes with the first gear, and an axial center formed at both ends of the gear main body;
Oldham shaft coupling that connects the rotating body and the shaft center portion;
A process cartridge comprising: a fixing portion that abuts on the shaft center portion of the second gear and fixes an inter-axis distance between the first gear and the second gear.   The process cartridge according to claim 1, wherein the fixing portion includes a restriction surface that restricts the second gear from moving in a direction in which a rotational driving force is input from the first gear.   3. The process cartridge according to claim 1, wherein the fixed portion is formed on a frame that holds the rotating body, and abuts against both ends of the shaft center portion of the second gear.   A holding member provided on one axial end side of the photosensitive drum and having a first holding portion that rotatably holds the photosensitive drum and a second holding portion that rotatably holds the axial center portion of the second gear. The process cartridge according to claim 1, further comprising:   The process cartridge according to claim 4, wherein a sheet metal for positioning the holding member is provided at the end portion in the axial direction.   The process cartridge according to claim 1, wherein the rotating body is a cleaning roller that cleans deposits on the peripheral surface of the photosensitive drum.

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