JP2017161614A - Process cartridge and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process cartridge in which pressure of a developing roller applied to a photosensitive drum is stable at both edges even when the process cartridge is a high capacity process cartridge.SOLUTION: A process cartridge B detachable from an apparatus main body of an image forming apparatus includes a first frame body 60 that rotatably supports an image carrier 62; a second frame body 20 that rotatably supports a developer carrier 32 opposite to the image carrier; a connecting shaft 69 that is fixed to the first frame body and is for rotatably connecting the first frame body with the second frame body; and a pressing member that presses the developer carrier against the image carrier. The second frame body includes a first support hole that is coupled with one end, in the axial direction of the image carrier, of the connecting shaft to cause the second frame to be rotatably positioned, and a second support hole 23b that causes the second frame body to be rotatably supported at the other edge, in the axial direction of the image carrier, of the connecting shaft, with a gap between the hole and the connecting shaft. The gap between the second support hole and the connecting shaft is larger in the radial direction of the connecting shaft than the gap between the first support hole and the connecting shaft.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a process cartridge and an image forming apparatus including the process cartridge.

  Here, the process cartridge is a cartridge in which a photosensitive drum and process means acting on the photosensitive drum are integrally formed, and is detachably mounted on the apparatus main body of the image forming apparatus.

  For example, a photosensitive drum and at least one of a developing unit, a charging unit, and a cleaning unit as the process unit are integrally formed into a cartridge. The image forming apparatus forms an image on a recording medium using, for example, an electrophotographic image forming system.

  Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (such as an LED printer and a laser beam printer), a facsimile machine, and a word processor.

  In an electrophotographic image forming apparatus (hereinafter, also simply referred to as “image forming apparatus”), an electrophotographic photosensitive member that is generally a drum type as an image carrier, that is, a photosensitive drum is uniformly charged. Next, an electrostatic latent image (electrostatic image) is formed on the photosensitive drum by selectively exposing the charged photosensitive drum. Next, the electrostatic latent image formed on the photosensitive drum is developed as a toner image with toner as a developer. Then, the toner image formed on the photosensitive drum is transferred to a recording material such as recording paper or plastic sheet, and the toner image is applied to the recording material by applying heat or pressure to the toner image transferred onto the recording material. Image recording is performed by fixing.

  Such an image forming apparatus generally requires toner replenishment and maintenance of various process means. In order to facilitate this toner replenishment and maintenance, a photosensitive cartridge, a charging unit, a developing unit, a cleaning unit, and the like are combined into a cartridge into a cartridge, and a process cartridge that can be attached to and detached from the main body of the image forming apparatus has been put into practical use. ing.

  According to this process cartridge system, since the user can perform maintenance of the apparatus himself, the operability can be remarkably improved, and an image forming apparatus excellent in usability can be provided. For this reason, this process cartridge system is widely used in image forming apparatuses.

  Further, as the above-described process cartridge, a cartridge in which a cleaning unit that holds a photosensitive drum, a cleaning unit, and the like and a developing unit that holds a developing roller that is a developer carrying member are coupled by a coupling shaft is generally known. . The coupling shaft is provided at one end (hereinafter referred to as driving side) and the other end (hereinafter referred to as non-driving side) of the photosensitive drum in the axial direction. And is rotatably supported. The developing unit supported rotatably by the coupling shaft is urged toward the cleaning unit by a pressure member such as its own weight or a spring. Therefore, the developing roller in the developing unit can be brought into contact with both ends in the cleaning unit with a constant pressure, and the image forming apparatus can stably form an image.

  However, in such a process cartridge, the position of the coupling shaft that couples the cleaning unit and the developing unit and the position of the hole that engages the coupling shaft due to the effects of component tolerances, etc., are the dimensions targeted at the time of design (hereinafter, , The reference dimension) may be deviated. When the position of the coupling shaft or the like is shifted, the coupling between the cleaning unit and the developing unit is affected. As a result, the pressure applied by the developing roller to the photosensitive drum may be greatly different between the driving side and the non-driving side.

  Therefore, in the conventional process cartridge, as disclosed in Patent Document 1 or Patent Document 2, a countermeasure is taken in which the hole on the non-driving side of the developing unit with which the coupling shaft is engaged is a long hole. As a result, even when the position of the coupling member or the like is deviated from the reference dimension, when the coupling member is engaged with the elongated hole, the engagement position between the elongated hole and the coupling member is moved, thereby causing the generated position. Can be absorbed. As a result, the pressure applied by the developing roller to the photosensitive drum is stabilized at both ends.

JP 08-339149 A Japanese Patent Laid-Open No. 09-050224

  In recent years, it has been desired to realize a process cartridge having a larger capacity. However, in order to realize this, the amount of toner is increased, and the weight of the developing unit is increased. Here, FIG. 16 shows a sectional view of the conventional process cartridge R as seen from the non-driving side. The developing unit 90 is rotatably supported by a coupling shaft 93 fixed to the cleaning unit 92. As shown in FIG. 16, the weight of the developing unit 90 in the initial stage (toner amount full) is M1, and the weight of the developing unit 90 in the second half of the end (empty toner amount) is M2. At this time, M1 >> M2, and the gravity center positions of M1 and M2 also change from L1 to L2. As a result, the optimum slot angle differs greatly between the slot 91 when the toner amount is full (FIG. 16B) and the slot 91 when the toner amount is empty (FIG. 16C). become.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a process cartridge in which the pressure applied by a developer carrying member such as a developing roller to an image carrier such as a photosensitive drum is stable at both ends even in a large capacity process cartridge.

  To achieve the above object, the present invention provides a process cartridge that can be attached to and detached from an apparatus main body of an image forming apparatus, a first frame that rotatably supports an image carrier, and a development that faces the image carrier. A second frame that rotatably supports the agent carrier, a coupling shaft that is fixed to the first frame, and that rotatably couples the first frame and the second frame; An urging member that urges the developer carrier to the image carrier, and the second frame is fitted to the coupling shaft at one end in the axial direction of the image carrier. A first support hole that is rotatably positioned, and a second support hole that is rotatably supported with a gap in the coupling shaft at the other end in the axial direction of the image carrier, The gap between the second support hole and the coupling shaft is in front of the first support hole in the radial direction of the coupling shaft. It is larger than the gap between the coupling shaft.

  According to the present invention, even in a large-capacity process cartridge, it is possible to provide a process cartridge in which the pressing force of the developer carrier to the image carrier is stable at both ends.

It is sectional drawing of the non-driving side edge part of the process cartridge which concerns on 1st Example. 1 is a cross-sectional view of an image forming apparatus main body and a process cartridge of an image forming apparatus according to a first embodiment. It is sectional drawing of the process cartridge which concerns on 1st Example. It is sectional drawing inside the cleaning container of the process cartridge which concerns on 1st Example. 1 is a perspective view of an image forming apparatus main body in a state where an opening / closing door of the image forming apparatus according to the first embodiment is opened. 1 is a perspective view of an image forming apparatus main body in a state where an opening / closing door of an image forming apparatus according to a first embodiment is opened and a tray is pulled out. FIG. 3 is a perspective view of the image forming apparatus main body and the process cartridge when the process cartridge is attached to and detached from the tray in a state where the opening / closing door of the image forming apparatus according to the first embodiment is opened and the tray is pulled out. FIG. 2 is a perspective view of a process cartridge and a driving side positioning portion of the image forming apparatus main body in a state where the process cartridge is mounted on the image forming apparatus main body according to the first embodiment. FIG. 3 is a perspective view of a process cartridge and a non-driving side positioning portion of the image forming apparatus main body in a state where the process cartridge is mounted on the image forming apparatus main body according to the first embodiment. It is an exploded view of the process cartridge according to the first embodiment. It is an exploded view of the process cartridge according to the first embodiment. It is an exploded view of the process cartridge according to the first embodiment. It is an exploded view of the process cartridge according to the first embodiment. It is sectional drawing of the drive side edge part of the process cartridge which concerns on 1st Example. It is the elements on larger scale of the process cartridge non-drive side end part concerning other examples. It is sectional drawing when it sees from the non-driving side of the process cartridge which shows a prior art example.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in the following embodiments should be appropriately changed according to the configuration of the apparatus to which the present invention is applied and various conditions. Therefore, unless specifically stated otherwise, the scope of the present invention is not intended to be limited thereto.

[Example 1]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the direction of the axis of rotation of the electrophotographic photosensitive drum as the image carrier is the longitudinal direction. In the longitudinal direction, the side on which the electrophotographic photosensitive drum receives driving force from the image forming apparatus main body is defined as a driving side, and the opposite side is defined as a non-driving side.

  The overall configuration of the image forming apparatus including the process cartridge and the image forming process will be described with reference to FIGS. FIG. 2 is a cross-sectional view of an image forming apparatus main body (hereinafter referred to as apparatus main body A) and a process cartridge (hereinafter referred to as cartridge B) of an electrophotographic image forming apparatus according to an embodiment of the present invention. . FIG. 3 is a cross-sectional view of the cartridge B. Here, the apparatus main body A is a portion obtained by removing the cartridge B from the electrophotographic image forming apparatus.

<Entire configuration of electrophotographic image forming apparatus>
The electrophotographic image forming apparatus shown in FIG. 2 is a laser beam printer using an electrophotographic technique in which a cartridge B is detachable from the apparatus main body A. When the cartridge B is mounted on the apparatus main body A, an exposure device 3 (laser scanner unit) for forming a latent image on the electrophotographic photosensitive drum 62 of the cartridge B is disposed. In addition, a sheet tray 4 that stores a recording medium (hereinafter referred to as a sheet material P) that is an image forming target is disposed below the cartridge B.

  Further, the apparatus main body A includes a pickup roller 5a, a feeding roller pair 5b, a conveyance roller pair 5c, a transfer guide 6, a transfer roller 7, a conveyance guide 8, a fixing device 9, along the conveyance direction D of the sheet material P. A pair of discharge rollers 10, a discharge tray 11, and the like are sequentially arranged. The fixing device 9 includes a heating roller 9a and a pressure roller 9b.

<Image formation process>
Next, an outline of the image forming process will be described. Based on the print start signal, the electrophotographic photosensitive drum (hereinafter referred to as drum 62) is rotationally driven in the direction of arrow R with a predetermined peripheral speed (process speed).

  The charging roller 66 to which the bias voltage is applied contacts the outer peripheral surface of the drum 62 and uniformly charges the outer peripheral surface of the drum 62.

  The exposure device 3 outputs a laser beam L corresponding to the image information. The laser light L passes through a laser opening 71 h provided in the cleaning frame 71 of the cartridge B, and scans and exposes the outer peripheral surface of the drum 62. As a result, an electrostatic latent image corresponding to the image information is formed on the outer peripheral surface of the drum 62.

  On the other hand, as shown in FIG. 3, in the developing unit 20 as a developing device, the toner T in the toner chamber 29 is stirred and transported by the rotation of the first transport member 43, the second transport member 44, and the third transport member 50. Then, it is sent out to the toner supply chamber 28.

  The toner T is carried on the surface of the developing roller 32 as a developer carrying member facing the drum 62 by the magnetic force of the magnet roller 34 (fixed magnet). The layer thickness of the toner T on the peripheral surface of the developing roller 32 is regulated while being frictionally charged by the developing blade 42. The toner T is developed on the drum 62 in accordance with the electrostatic latent image, and is visualized as a toner image.

  Further, as shown in FIG. 2, the sheet material P stored in the lower part of the apparatus main body A is moved to the sheet tray by the pickup roller 5a, the feeding roller pair 5b, and the conveying roller pair 5c in accordance with the output timing of the laser beam L. 4 is sent out. Then, the sheet material P is conveyed to the transfer position between the drum 62 and the transfer roller 7 via the transfer guide 6. At this transfer position, the toner images are sequentially transferred from the drum 62 to the sheet material P.

  The sheet material P to which the toner image has been transferred is separated from the drum 62 and conveyed to the fixing device 9 along the conveyance guide 8. The sheet material P passes through the nip portion between the heating roller 9a and the pressure roller 9b constituting the fixing device 9. A pressure / heat fixing process is performed in the nip portion, and the toner image is fixed on the sheet material P. The sheet material P that has undergone the toner image fixing process is conveyed to the discharge roller pair 10 and discharged to the discharge tray 11.

  On the other hand, as shown in FIG. 3, the drum 62 after the transfer is used again in the image forming process after the residual toner on the outer peripheral surface is removed by the cleaning member 77. The toner removed from the drum 62 is stored in the waste toner chamber 71 b of the cleaning unit 60.

  In the above, the charging roller (charging means) 66, the developing roller (developing means) 32, the transfer roller (transfer means) 7, and the cleaning member (cleaning means) 77 are process means that act on the drum 62.

<Removal of cartridge>
Next, attachment / detachment of the cartridge B with respect to the apparatus main body A will be described with reference to FIGS.

  FIG. 5 is a perspective view of the apparatus main body A with the open / close door 13 opened in order to attach and detach the cartridge B. FIG. FIG. 6 is a perspective view of the apparatus main body A and the cartridge B in a state in which the opening / closing door 13 is opened and the tray 18 is pulled out in order to attach and detach the cartridge B. FIG. 7 is a perspective view of the apparatus main body A and the cartridge B when the cartridge B is attached and detached with the open / close door 13 opened and the tray 18 pulled out. The cartridge B can be attached to and detached from the tray 18 along the attaching / detaching direction E.

  An opening / closing door 13 is rotatably attached to the apparatus main body A, and a cartridge insertion opening 17 is provided when the opening / closing door 13 is opened. A tray 18 for mounting the cartridge B to the apparatus main body A is provided in the cartridge insertion opening 17. When the tray 18 is pulled out to a predetermined position, the cartridge B can be attached and detached. The cartridge B is mounted in the apparatus main body A along a guide rail (not shown) in the direction of arrow C in the figure while being placed on the tray 18.

  Further, the apparatus main body A is provided with a first drive shaft 14 and a second drive shaft 19 for transmitting drive to the first coupling 70 and the second coupling 21 (FIG. 8) provided in the cartridge B. ing. The first drive shaft 14 and the second drive shaft 19 are driven by a motor (not shown) of the apparatus main body A. As a result, the drum 62 connected to the first coupling 70 is rotated by receiving a driving force from the apparatus main body A. Further, the driving force is transmitted from the second coupling 21, and the developing roller 32 rotates. Further, the charging roller 66 and the developing roller 32 are supplied with power from a power supply unit (not shown) of the apparatus main body A.

<Cartridge support>
As shown in FIG. 5, the apparatus main body A is provided with a driving side plate 15 and a non-driving side plate 16 for supporting the cartridge B. As shown in FIGS. 8 and 9, the drive side plate 15 is provided with a drive side first support portion 15a, a drive side second support portion 15b, and a rotation support portion 15c of the cartridge B. The non-driving side plate 16 is provided with a non-driving side first support portion 16a, a non-driving side second support portion 16b, and a rotation support portion 16c.

  On the other hand, as supported portions of the cartridge B, a supported portion 73b and a supported portion 73d of the drum bearing 73, a driving side boss 71a of the cleaning frame 71, a non-driving side protrusion 71f, and a non-driving side boss 71g are provided. ing. The supported portion 73b is supported by the drive side first support portion 15a, the supported portion 73d is supported by the drive side second support portion 15b, and the drive side boss 71a is supported by the rotation support portion 15c. Further, the non-driving side protrusion 71f is supported by the non-driving side first support portion 16a and the non-driving side second support portion 16b, and the non-driving side boss 71g is supported by the rotation support portion 16c, whereby the cartridge B is It is positioned in the apparatus main body A.

<Configuration of the entire cartridge>
Next, the entire configuration of the cartridge B will be described with reference to FIGS. 3, 4, 10, 11, 12, and 13. FIG. 3 is a cross-sectional view of the cartridge B. 10, 11, 12, and 13 are perspective views illustrating the configuration of the cartridge B. FIG. FIGS. 11 and 13 are partial enlarged views in which portions within the dotted line portions of FIGS. 10 and 12 are enlarged at different angles. In the present embodiment, the screws for connecting the parts will be omitted.

  The cartridge B has a cleaning unit 60 and a developing unit 20. The process cartridge is a cartridge in which an electrophotographic photosensitive member and at least one of a charging unit, a developing unit, and a cleaning unit acting as a process unit acting on the electrophotographic photosensitive member are integrated into a cartridge, and the main body of the electrophotographic image forming apparatus. Can be attached and detached. In the present invention, the process cartridge has at least the cleaning unit 60 according to the present invention.

  As shown in FIG. 3, the cleaning unit 60 includes a drum 62, a charging roller 66, a cleaning member 77, a cleaning frame body 71 that supports them, and a lid member 72 fixed to the cleaning frame body 71 by welding or the like. Have In the cleaning unit 60, the charging roller 66 and the cleaning member 77 are disposed in contact with the outer peripheral surface of the drum 62.

  The cleaning member 77 includes a rubber blade 77a that is a blade-like elastic member formed of rubber as an elastic material, and a support member 77b that supports the rubber blade. The rubber blade 77 a is in contact with the drum 62 in the counter direction with respect to the rotation direction of the drum 62. That is, the rubber blade 77 a is in contact with the drum 62 so that the tip end portion thereof faces the upstream side in the rotation direction of the drum 62.

  FIG. 4 is a cross-sectional view of the cleaning frame 71. As shown in FIGS. 3 and 4, the waste toner removed from the surface of the drum 62 by the cleaning member 77 is a first screw 86, a second screw 87, and a third screw 88 as waste toner transport members (transport members). Is conveyed by. Then, the toner is stored in a waste toner chamber 71 b formed by the cleaning frame 71 and the lid member 72. Further, the first screw 86 is rotated by a drive transmitted from the coupling 21 shown in FIG. 13 by a gear (not shown). The second screw 87 receives the driving force from the first screw 86 and the third screw 88 rotates from the second screw 87, respectively. The first screw 86 is disposed near the drum 62, the second screw 87 is disposed at the longitudinal end of the cleaning frame 71, and the third screw 88 is disposed in the waste toner chamber 71b. Here, the rotation axes of the first screw 86 and the third screw 88 are parallel to the rotation axis of the drum 62, and the rotation axis of the second screw 87 is orthogonal to the rotation axis of the drum 62.

  Further, as shown in FIG. 3, a squeeze sheet 65 for preventing waste toner from leaking from the cleaning frame 71 is provided at the edge of the cleaning frame 71 so as to contact the drum 62.

  The drum 62 is rotationally driven in the direction of arrow R in the drawing according to an image forming operation by receiving a driving force from a main body driving motor (not shown) as a driving source.

  The charging roller 66 is rotatably attached to the cleaning unit 60 via a charging roller bearing 67 at both ends in the longitudinal direction of the cleaning frame 71 (substantially parallel to the rotation axis direction of the drum 62). The charging roller 66 is in pressure contact with the drum 62 by the charging roller bearing 67 being pressed toward the drum 62 by the biasing member 68. The charging roller 66 rotates following the rotation of the drum 62.

  As shown in FIG. 3, the developing unit 20 includes a developing roller 32, a developing container 23 that supports the developing roller 32, a developing blade 42, and the like. A magnet roller 34 is provided in the developing roller 32. In the developing unit 20, a developing blade 42 for restricting the toner layer on the developing roller 32 is disposed. As shown in FIGS. 10 and 12, a spacing member 38 is attached to the developing roller 32 at both ends of the developing roller 32. The drum 62 is held with a slight gap. Further, as shown in FIG. 3, a blowout prevention sheet 33 for preventing the toner from leaking from the developing unit 20 is provided at the edge of the bottom member 22 so as to contact the developing roller 32. Further, the toner chamber 29 formed by the developing container 23 and the bottom member 22 is provided with a first transport member 43, a second transport member 44, and a third transport member 50. The first conveyance member 43, the second conveyance member 44, and the third conveyance member 50 agitate the toner stored in the toner chamber 29 and convey the toner to the toner supply chamber 28.

  As shown in FIGS. 10 and 12, the cartridge B is configured by combining the cleaning unit 60 and the developing unit 20.

  The cleaning unit 60 is provided with a cleaning frame 71 as a first frame, a lid member 72, a drum 62, and a drum bearing 73 and a drum shaft 78 for rotatably supporting the drum 62. As shown in FIG. 13, on the driving side, the drum 62 is rotatably supported by a hole 73 a of a drum bearing 73 on a driving side drum flange 63 provided on the driving side. On the other hand, as shown in FIG. 11, on the non-driving side, the drum shaft 78 press-fitted into the hole 71c provided in the cleaning frame 71 can rotate the hole (not shown) of the non-driving side drum flange 64. It is the structure which supports to. Thus, the drum 62 is rotatably supported by the cleaning frame 71 and the drum bearing 73 as the first frame.

  As shown in FIGS. 3, 10, and 12, the developing unit 20 includes a bottom member 22, a developing container 23 as a second frame, a driving side developing side member 26, a developing blade 42, a developing roller 32, and the like. Become. The developing roller 32 is attached to a developing container 23 as a second frame so as to be rotatable by bearing members 27 and 37 provided at both ends.

  Then, as shown in FIGS. 11 and 13, the cartridge B is configured by rotatably connecting the cleaning unit 60 and the developing unit 20 with a connecting pin 69 as a connecting shaft.

  Specifically, at both ends in the longitudinal direction of the developing unit 20, a developing container 23 as a second frame body has a developing first support hole 23a as a positioning hole and a developing second support hole 23b as a play hole. Is provided. Further, at both ends in the longitudinal direction of the cleaning unit 60, a first suspension hole 71i and a second suspension hole 71j are provided in a cleaning frame body 71 as a first frame body. In the cartridge B, at one end portion in the axial direction of the drum 62, a coupling pin 69 as a coupling shaft press-fitted and fixed to the first suspension hole 71i and the developing first support hole 23a are fitted. Further, in the cartridge B, at the other end in the axial direction of the drum 62, a coupling pin 69 as a coupling shaft press-fitted and fixed in the second suspension hole 71j is engaged with the development second support hole 23b. Accordingly, the cleaning unit 60 and the developing unit 20 are connected to each other so as to be rotatable.

  The first hole 46Ra of the driving side biasing member 46R is hooked on the boss 73c of the drum bearing 73, and the second hole 46Rb is hooked on the boss 26a of the driving side developing side member 26.

  Further, the first hole 46Fa of the non-driving side urging member 46F is hooked on the boss 71k of the cleaning frame 71, and the second hole 46Fb is hooked on the boss 37a of the bearing member 37.

  In this embodiment, the driving side urging member 46R and the non-driving side urging member 46F are formed by tension springs. The developing unit 20 is urged toward the cleaning unit 60 by the urging force of the spring so that the developing roller 32 is surely pressed toward the drum 62. The developing roller 32 is held at a predetermined interval from the drum 62 by a spacing holding member 38 attached to both ends of the developing roller 32.

<Pressure configuration of developing roller against photosensitive drum>
The configuration of pressing the developing roller against the photosensitive drum will be described in detail with reference to FIGS. FIG. 1A is a cross-sectional view of the process cartridge at the non-driving side end (A2-A2 cross-sectional view of FIG. 9), and FIGS. 1B to 1D are coupling pins 69 shown in FIG. FIG. 6 is a partially enlarged view showing the second developing support hole 23b. 14A is a cross-sectional view of the process cartridge at the drive side end (A1-A1 cross-sectional view of FIG. 8), and FIG. 14B is a diagram illustrating the coupling pin 69 and the first developing support shown in FIG. It is the elements on larger scale which show the hole 23a.

  First, the configuration on the drive side will be described with reference to FIGS. 14 (a) and 14 (b). As described above, on the driving side, the coupling pin 69 press-fitted and fixed in the first suspension hole 71 i and the development first support hole 23 a are fitted, and the development unit 20 is positioned with respect to the cleaning unit 60. It is in a state. At this time, the developing roller 32 is pressed in the direction of the drum 62 by the moment M1 due to the developing unit weight G1 and the urging force F1 due to the driving side urging member 46R (not shown in FIG. 14, see FIG. 8), and the pressure P1 is applied. It will be. Here, FIG. 14B is a partially enlarged view showing the coupling pin 69 and the development first support hole 23a, and the fitting amount between the coupling pin 69 and the development first support hole 23a is t1. Here, the fitting amount t1 is a gap between the developing first support hole 23a on the driving side and the connecting pin (connecting shaft) 69 in the radial direction of the connecting pin 69 (FIG. 14B). reference).

  Next, the configuration on the non-driving side will be described with reference to FIGS. On the non-driving side, the diameter r2 of the development second support hole 23b is formed larger than the diameter r1 of the coupling pin 69, and the developing unit 20 has a backlash amount t2 (= r2-r1) with respect to the cleaning unit 60. Supported in some state. At this time, similarly to the driving side, the developing roller 32 is pressed in the direction of the drum 62 by the moment M2 due to the developing unit weight G2 and the urging force F2 due to the non-driving side urging member 46F (not shown in FIG. 1, see FIG. 9). The pressing force P2 is applied.

  Here, when the toner amount in the developing unit 20 is full, the developing unit 20 moves in the direction of the arrow N1 in FIG. 1C due to its weight, and the connecting pin 69 and the developing second support hole 23b are in FIG. (C) Abut at the point c1 in the middle. On the other hand, when the toner amount in the developing unit 20 is empty, the developing unit 20 moves in the direction of the arrow N2 in FIG. 1D, and the coupling pin 69 and the development second support hole 23b are in FIG. The contact is made at the point d1. At this time, even if the developing unit 20 is moved during distribution or by a user operation, the play amount t2 is provided by the coupling pin 69 and the developing second support hole 23b, so that the developing unit 20 returns to a predetermined position (c1, d1). Can do.

  Here, with reference to FIG. 1A, the positional relationship between the coupling pin 69, the drum 62, the developing roller 32, and the third screw 88 in a state where the cartridge B is mounted on the apparatus main body A will be described. To do. The state shown in FIGS. 1A and 2 is a state where the cartridge B is mounted on the apparatus main body A. FIG.

  As shown in FIG. 1A, the drum 62 is positioned so as to be aligned in the horizontal direction with respect to the coupling pin 69. The developing roller 32 is positioned below the drum 62 and aligned with the connecting pin 69 in the horizontal direction. The center 32 c of the developing roller 32 is located below the center 69 c of the coupling pin 69 and located below the center 62 c of the drum 62. The center 69 c of the connecting pin 69 is located above the center 62 c of the drum 62 and is located below the center 88 c of the third screw 88. This cartridge B is a process cartridge in which the positional relationship between the coupling pin 69, the drum 62, the developing roller 32, and the third screw 88 is as described above when mounted on the apparatus main body A. is there.

  Next, the backlash amount t2 of the developing unit 20 with respect to the cleaning unit 60 on the non-driving side will be described in detail. Here, the backlash amount t2 is the gap between the developing second support hole 23b on the non-driving side and the coupling pin (coupling shaft) 69 in the radial direction of the coupling pin 69 (FIG. 1B). reference). More specifically, the gap t2 between the development second support hole 23b and the coupling pin 69 overlaps the center of the development second support hole 23b and the center of the coupling pin 69 as shown in FIG. This is the difference between the radius r2 of the development second support hole 23b and the radius r1 of the connecting pin 69.

  First, in the cleaning unit 60, a coupling pin 69 (see FIG. 14A) is press-fitted and fixed in the first suspension hole 71i (see FIG. 13), and this is used as a reference. With respect to this standard, the coupling pin 69 (see FIG. 1A) press-fitted and fixed in the second suspension hole 71j (see FIG. 11) has a3 = a1 + a2 (FIG. 1A, FIG. 14 (a) may cause a misalignment in the middle arrow X direction. Hereinafter, the coupling pin 69 press-fitted and fixed in the first suspension hole 71i on the driving side is referred to as a driving-side coupling pin, and the coupling pin 69 press-fitted and fixed in the second suspension hole 71j on the non-driving side is referred to as a non-driving side coupling pin. . Here, a1 (see FIG. 14A) is a dimensional tolerance (in the direction of arrow X in FIG. 14A) of each part from the drive side coupling pin 69 to the drum 62. Further, a2 (see FIG. 1A) is a dimensional tolerance (in the direction of arrow X in FIG. 1A) of each component from the non-driving side coupling pin 69 to the drum 62.

  Similarly, when the development unit 20 is based on the development first support hole 23a (see FIG. 14A), the development second support hole 23b (see FIG. 1A) is b3 = A positional deviation of b1 + b2 (in the direction of arrow X in FIGS. 1A and 14A) may occur. Here, b1 (see FIG. 14A) is a dimensional tolerance (in the direction of arrow X in FIG. 14A) of each component from the first development support hole 23a to the developing roller 32. Further, b2 (see FIG. 1A) is a dimensional tolerance (in the direction of arrow X in FIG. 1A) from the development second support hole 23b to the development roller 32.

  At this time, by setting t2 = a3 + b3 with respect to the positional deviations a3 and b3, the respective positional deviations can be absorbed. That is, even if the positional deviations a3 and b3 occur, stable pressures P1 and P2 can be realized. Here, although only the positional deviation in the X direction has been described, the positional deviations a3 and b3 may occur in all directions. However, as shown in FIG. 1 (b), the development second support hole 23b is provided with a backlash t2 in all directions with respect to the coupling pin 69, so that no matter which direction the position shifts, The applied pressures P1 and P2 can be realized.

  Here, for example, it is assumed that the backlash amount t2 of the developing second support hole 23b with respect to the connecting pin 69 is equal to the fitting amount t1 between the connecting pin 69 and the developing first support hole 23a (t2 = t1). At this time, the development unit 20 is twisted in the directions of the arrows Q1 and Q2 in FIG. 1A in order to avoid the positional deviation between the non-drive side coupling pin 69 and the development second support hole 23b. Due to the twists Q1 and Q2 of the developing unit 20, the pressure P2 increases and decreases. As a result, the difference (P1 >> P2, P1 << P2) between the applied pressures P1 and P2 increases. On the other hand, it is assumed that the backlash amount t2 of the development second support hole 23b with respect to the coupling pin 69 is larger than the positional deviation a3 + b3 on the driving side and the non-driving side (t2> a3 + b3). At this time, although the amount that can absorb the misalignment increases, the amount that the developing unit 20 can move during distribution or user operation increases. Therefore, there is a concern that the operability is lowered. As described above, it is desirable that the backlash amount t2 is t2 = a3 + b3, and is the minimum amount that can absorb each positional shift.

  As described above, in this embodiment, the diameter r2 of the development second support hole 23b is made larger than the diameter r1 of the non-driving side coupling pin 69, and the play amount t2 is provided. Thereby, even in a large-capacity process cartridge, it is possible to provide a process cartridge in which the pressure applied by the developing roller to the photosensitive drum is stable at both ends.

[Other Examples]
In the above-described embodiment, the development second support hole 23b has been described as having a circular shape, but the same effect can be obtained with a hole having a different shape.

  FIG. 15 is a partially enlarged view showing the configuration of the irregularly-shaped development second support hole. In FIG. 15A, the development second support hole 81 is a square hole, and in FIG. 15B, the development second support hole 82 is a fan-shaped hole. In each hole, a backlash amount t3 to t6 is provided for the non-driving side coupling pin 69. Here, by setting t3 to t6 = t2, it is possible to obtain an effect similar to that of a circular hole even in an irregularly shaped hole. The backlash amounts t3 to t6 of the development second support holes 81 and 82 with respect to the non-driving side coupling pin 69 shown in FIGS. 15A and 15B are also different from those of the first embodiment described above, although the hole shapes are different. It is the same. That is, the gap t3 between the development second support hole 81 and the coupling pin 69 shown in FIG. 15A is obtained when the center of the development second support hole 81 and the center of the coupling pin 69 are overlapped. This is the difference between the length r3 to the center of the side 81a of the development second support hole 81 and the radius r1 of the connecting pin 69. Further, the gap t4 between the development second support hole 81 and the coupling pin 69 shown in FIG. 15A is obtained when the center of the development second support hole 81 and the center of the coupling pin 69 are overlapped. This is the difference between the length r 4 to the center of the side 81 b of the development second support hole 81 and the radius r 1 of the connecting pin 69. Further, the gap t5 between the development second support hole 82 and the coupling pin 69 shown in FIG. 15B is obtained when the center of the development second support hole 82 and the center of the coupling pin 69 are overlapped. This is the difference between the length r5 to the center of the side 82a of the development second support hole 82 and the radius r1 of the connecting pin 69. In addition, the gap t6 between the development second support hole 82 and the coupling pin 69 shown in FIG. 15B is obtained when the center of the development second support hole 82 and the center of the coupling pin 69 are viewed in an overlapping manner. This is the difference between the length r6 to the center of the side 82b of the development second support hole 82 and the radius r1 of the connecting pin 69. Here, the center of the development second support hole 81 is an intersection of square diagonal lines. The center of the development second support hole 82 is an intersection of perpendicular lines from the center of the straight lines (sides 82b) on both sides connecting the respective arcs (sides 82a).

  Further, the same effect can be obtained by a configuration in which an elastic member is provided on the backlash formed by the non-driving side coupling pin 69 and the development second support hole 23b.

  In the above-described embodiment, the cleaning frame constituting the cleaning unit is exemplified as the first frame that rotatably supports the image carrier. However, the present invention is not limited to this. For example, any other frame body may be used as long as it is a frame body that rotatably supports the image carrier, such as a frame body constituting a drum unit having no cleaning member.

  In the above-described embodiment, the configuration in which the number of process cartridges that can be attached to and detached from the apparatus main body of the image forming apparatus is one is illustrated. However, the number of use is not limited, and may be appropriately set as necessary. Set it.

  In the above-described embodiments, the printer is exemplified as the image forming apparatus. However, the present invention is not limited to this, and other image forming apparatuses such as a copying machine and a facsimile machine, or a combination of these functions. Other image forming apparatuses such as multifunction peripherals may also be used. Further, an image forming apparatus that uses a recording medium carrier and sequentially superimposes and transfers the toner images of the respective colors onto the recording medium carried on the recording medium carrier. Alternatively, an image forming apparatus that uses an intermediate transfer member, sequentially superimposes and transfers toner images of each color on the intermediate transfer member, and collectively transfers the toner images carried on the intermediate transfer member onto a recording medium. Also good. The same effect can be obtained by applying the present invention to a process cartridge installed in these image forming apparatuses.

A: Device main body B: Cartridge P ... Sheet material T ... Toner a3, b3 ... Position shift r1, r2 ... Radius r3, r4, r5, r6 ... Length t1 ... Fitting amount (gap)
t2, t3, t4, t5, t6 ... amount of play (gap)
20 ... development unit (second frame)
23a ... development first support hole 23b ... development second support hole 32 ... development roller (developer carrier)
46F, 46R ... biasing member 60 ... cleaning unit (first frame)
62 ... drum (image carrier)
69… Coupling pin (Coupling shaft)
71 ... Cleaning frame 71i ... 1st suspension hole 71j ... 2nd suspension hole 77 ... Cleaning member 78 ... Drum shaft 86 ... 1st screw 87 ... 2nd screw 88 ... 3rd screw

Claims (12)

A process cartridge that can be attached to and detached from the main body of the image forming apparatus,
A first frame for rotatably supporting the image carrier;
A second frame that rotatably supports the developer carrier facing the image carrier;
A coupling shaft fixed to the first frame body and rotatably coupled to the first frame body and the second frame body;
A biasing member that biases the developer carrier to the image carrier;
The second frame has a first support hole that is fitted to the coupling shaft at one end in the axial direction of the image carrier and is positioned so as to be rotatable, and an axis of the image carrier A second support hole rotatably supported with a gap on the coupling shaft at the other end in the direction,
The process cartridge according to claim 1, wherein a gap between the second support hole and the coupling shaft is larger than a gap between the first support hole and the coupling shaft in a radial direction of the coupling shaft.   The gap between the second support hole and the coupling shaft is such that the center of the second support hole and the center of the coupling shaft overlap each other and the radius of the second support hole and the coupling shaft. The process cartridge according to claim 1, wherein the process cartridge is a difference from a radius.   The process cartridge according to claim 1, wherein the second support hole is formed in a circular shape.   The gap between the second support hole and the coupling axis is the center of each side forming the second support hole 81 when the center of the second support hole and the center of the coupling axis are viewed overlapping each other. The process cartridge according to claim 1, wherein the process cartridge is a difference between a length up to and a radius of the coupling shaft.   The process cartridge according to claim 1, wherein the second support hole is formed in a square shape or a sector shape.   6. The process cartridge according to claim 1, wherein an elastic member is provided between the second support hole and the coupling shaft.   The gap t2 between the second support hole and the coupling shaft is a positional deviation a3 due to a dimensional tolerance of the component from the coupling shaft to the image carrier, and a component t from the coupling shaft to the developer carrier. 7. The process cartridge according to claim 1, wherein t2 = a3 + b3 with respect to the positional deviation b3 due to the dimensional tolerance.   The first support hole is provided on a driving side where the image carrier receives a driving force from the apparatus main body, and the second support hole is on the side opposite to the driving side in the axial direction of the image carrier. The process cartridge according to claim 1, wherein the process cartridge is provided on a non-driving side.   9. The image forming apparatus according to claim 1, wherein the image carrier is positioned so as to be aligned in a horizontal direction with respect to the coupling shaft in a state where the image carrier is mounted on the apparatus main body of the image forming apparatus. Process cartridge.   The developer carrier is positioned below the image carrier and arranged in a horizontal direction with respect to the coupling shaft in a state where the developer carrier is attached to the apparatus main body of the image forming apparatus. The process cartridge according to claim 1. The first frame further includes a cleaning member that removes the developer from the image carrier, and a transport member that transports the developer removed by the cleaning member,
The center of the coupling shaft is located above the center of the image carrier and is located below the center of the transport member when mounted on the apparatus main body of the image forming apparatus. 9. The process cartridge according to any one of items 1 to 8.   12. An image forming apparatus, wherein the process cartridge is detachable from the apparatus main body and forms an image on a recording medium, comprising the process cartridge according to any one of claims 1 to 11. apparatus.

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