JP2015169849A - Developing unit, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing unit that can suppress reduction in the accuracy of drive transmission by a drive train that transmits the drive to a developing roller provided in the developing unit, and a process cartridge and an image forming apparatus including the developing unit.SOLUTION: A developing unit 9 includes a rotatable developer carrier 6, a drive input part 74b that receives the input of a rotational driving force to rotate the developer carrier 6, and a plurality of gears 68 and 69 that transmit the rotational driving force transmitted from the drive input part 74b to the developer carrier 6. At least one of the plurality of gears has a tooth surface in a crowning shape where the thickness at the center part in the tooth width direction is larger than the thickness at the ends in the tooth width direction.

Description

  The present invention relates to a developing unit used in an image forming apparatus using an electrophotographic system or an electrostatic recording system, a process cartridge including the developing unit, and an image forming apparatus thereof.

  2. Description of the Related Art Conventionally, for example, in an electrophotographic image forming apparatus, a developing unit for developing an electrostatic latent image formed on an electrophotographic photosensitive member (hereinafter also simply referred to as “photosensitive member”) as an image carrier with toner. Used. The developing unit may be detachable from the apparatus main body of the image forming apparatus alone, or may be detachable from the apparatus main body of the image forming apparatus by forming a process cartridge together with the photosensitive member. In the developing unit, in order to develop an electrostatic latent image on a photosensitive member, a developing roller as a developer carrying member that carries and conveys toner as a developer is rotated at a predetermined speed. .

  As a configuration for rotationally driving the developing roller, there is provided an idler gear that is driven to rotate by being transmitted from the image forming apparatus main body, and a developing roller gear attached to the developing roller, and the developing roller gear is rotationally driven via the idler gear. (Patent Document 1). That is, the developing roller gear is fitted to the end portion of the developing roller supported by the bearing member in the rotation axis direction. Further, both ends of the idler gear in the rotation axis direction are supported by the bearing member and the developing cover member attached to the end of the developing unit. The idler gear meshes with the developing roller gear, and a rotational driving force (rotational force) is input from the image forming apparatus main body to the coupling portion of the idler gear, whereby the developing roller gear is rotationally driven.

JP 2012-27449 A

  In the configuration of the drive train described above, both ends of the idler gear in the rotation axis direction are rotatably supported by the bearing member and the developing cover member, respectively. For this reason, if the control of the dimensional accuracy of the part and the assembly accuracy of the part is insufficient or the member is deformed, there is a relative displacement between the idler gear support center of the bearing member and the idler gear support center of the developing cover member. Arise. The idler gear support center of the bearing member is the rotation center of the idler gear at the position of the bearing member in the rotational axis direction of the idler gear, and the idler gear support center of the developing cover member is the rotational center of the idler gear at the position of the developing cover member.

  Due to the relative displacement of the respective idler gear support centers, an inclination occurs in the rotation axis of the idler gear. As a result, the developing roller gear and the idler gear mesh with each other while the rotation axis of the developing roller gear and the rotation axis of the idler gear are not parallel to each other. When the drive transmission accuracy is lowered, the rotation accuracy of the developing roller is lowered, and development unevenness of the electrostatic latent image on the photosensitive member is generated and may appear as a horizontal stripe on the image. For this reason, the tilting of the rotation axis of the idler gear is suppressed by strictly controlling the component accuracy and assembly accuracy of the bearing member and the developing cover member, or by applying an expensive high-rigidity material so that each member does not deform. May be necessary.

  Even when only one end of the idler gear in the rotation axis direction is supported, the rotation axis of the idler gear and the rotation axis of the developing roller gear become non-parallel due to the same factors as the accuracy and deformation described above. There may be a problem similar to the above. The same applies to the case where the rotation axis of the developing roller gear or the rotation axis of both the idler gear and the developing roller gear is inclined so that the rotation axis of the idler gear and the rotating axis of the developing roller gear are not parallel.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a developing unit that can suppress a reduction in drive transmission accuracy of a drive train that transmits drive to a developing roller provided in the developing unit, a process cartridge and an image forming apparatus including the developing unit. Is to provide.

  The above object is achieved by the developing unit, the process cartridge, and the image forming apparatus according to the present invention. In summary, the present invention relates to a rotatable developer carrier, a drive input unit to which a rotational drive force for rotating the developer carrier is input, and a rotational drive force transmitted from the drive input unit. A developing unit having a plurality of gears that transmit to the developer carrying member, wherein the tooth surface of at least one of the plurality of gears has a central portion in the tooth width direction that is thicker than the thickness of the end portion in the tooth width direction. The developing unit has a crowning shape in which the thickness is increased.

  According to another aspect of the present invention, there is provided an electrophotographic photosensitive member, and the developing unit of the present invention for developing an electrostatic image formed on the electrophotographic photosensitive member, and an apparatus main body of an image forming apparatus A process cartridge that can be attached to and detached from the camera is provided.

  According to another aspect of the present invention, there is provided an image forming apparatus having an image carrier and the developing unit of the present invention for developing an electrostatic image formed on the image carrier.

  According to the present invention, it is possible to suppress a decrease in drive transmission accuracy of a drive train that transmits drive to a developing roller provided in the developing unit.

1 is a cross-sectional view of an image forming apparatus. 1 is a perspective view of an image forming apparatus. It is sectional drawing of a process cartridge. It is an assembly perspective view of a process cartridge. It is an assembly perspective view of a process cartridge. It is a side view of a process cartridge. It is an exploded view of the drive connection part of a process cartridge. It is an exploded view of the drive connection part of a process cartridge. It is operation | movement explanatory drawing of a drive connection mechanism. It is operation | movement explanatory drawing of a drive connection mechanism. It is sectional drawing of a drive connection mechanism. It is operation | movement explanatory drawing of a drive connection mechanism. It is operation | movement explanatory drawing of a drive connection mechanism. It is operation | movement explanatory drawing of a drive connection mechanism. It is operation | movement explanatory drawing of a drive connection mechanism. FIG. 4 is a cross-sectional view of the image forming apparatus illustrating a process cartridge attaching / detaching operation. FIG. 4 is a cross-sectional view of the image forming apparatus illustrating a process cartridge attaching / detaching operation. It is the perspective view and expansion perspective view of the developing roller gear which concern on one Example of this invention. It is the front view and expanded sectional view of the developing roller gear which concern on one Example of this invention. It is the perspective view and enlarged perspective view of an idler gear. FIG. 4 is a plan view of a drive train that transmits driving force to a developing roller. FIG. 5 is a side view of a drive train that transmits driving force to a developing roller. It is sectional drawing which shows the meshing state of the gear which concerns on one Example of this invention. It is a graph which shows the rotation precision which concerns on one Example of this invention. It is the perspective view of the idler gear of the modification which concerns on one Example of this invention, and the front view of a drive train. It is a front view of the drive train of the other modification which concerns on one Example of this invention. It is a front view of the drive train for demonstrating the difference in the rigidity of a developing cover member. It is the perspective view and expansion perspective view of the developing roller gear of a comparative example. It is sectional drawing which shows the meshing state of the gear which concerns on a comparative example.

  Hereinafter, a developing unit, a process cartridge, and an image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

Example 1
[Overall Configuration of Image Forming Apparatus]
First, the overall configuration of an image forming apparatus using the developing unit of this embodiment will be described. In this embodiment, the image forming apparatus is an electrophotographic image forming apparatus (electrophotographic image forming apparatus) adopting a process cartridge system.

  Here, the electrophotographic image forming apparatus forms an image on a recording medium using an electrophotographic image forming process. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (laser beam printer, LED printer, etc.), a facsimile machine, and a word processor. Further, the process cartridge is a cartridge in which a photosensitive member (electrophotographic photosensitive member) and at least a developing unit serving as a processing unit that acts on the photosensitive member are integrally formed into a cartridge that can be attached to and detached from the image forming apparatus main body. It is. The developing unit is an apparatus (developing apparatus) in which developing means used for developing the electrostatic latent image on the photoreceptor is integrated. The developing unit has at least a developing roller as a developer carrying member constituting the developing means. The developing unit is mounted on the main body of the image forming apparatus in a state in which a part of the process cartridge is configured or the developing unit alone. The developing unit may be a developing cartridge that is detachable from the main body of the image forming apparatus alone. The image forming apparatus main body (hereinafter also simply referred to as “apparatus main body”) is an image forming apparatus portion excluding the process cartridge and the developing cartridge.

  In this embodiment, the image forming apparatus is a full-color image forming apparatus in which four process cartridges (hereinafter also simply referred to as “cartridges”) are detachable. However, the number of cartridges attached to the image forming apparatus is not limited to this. It is appropriately set as necessary. For example, in the case of an image forming apparatus that forms a monochrome image, the number of cartridges attached to the image forming apparatus is one. In this embodiment, the image forming apparatus is a laser beam printer.

  FIG. 1 is a cross-sectional view of the image forming apparatus 1 of the present embodiment. 2A and 2B are perspective views of the image forming apparatus according to the present exemplary embodiment showing different states to be described later. As shown in FIG. 1, the image forming apparatus 1 has four cartridges PY, PM, PC, and PK removably attached to the apparatus main body 2 and a recording medium such as recording paper using an electrophotographic image forming process. (Recording material, transfer material) A full-color image is formed on the S. The four cartridges PY, PM, PC, and PK are for forming images of each color of yellow (Y), magenta (M), cyan (C), and black (K), respectively. As will be described in detail later, these cartridges PY, PM, PC, and PK can be easily attached to the apparatus main body 2 by the user himself / herself without opening the front door 3 of the image forming apparatus 1. It can be attached and detached.

  Here, regarding the image forming apparatus 1, the side on which the front door 3 is provided is defined as a front surface (front surface), and the surface opposite to the front surface is defined as a back surface (rear surface). Further, when the image forming apparatus 1 is viewed from the front, the right side is the driving side and the left side is the non-driving side. In this embodiment, the four cartridges PY, PM, PC, and PK each have the same electrophotographic image forming process mechanism, and the developer colors used are different. Therefore, in the following, when there is no particular distinction, Y and M at the end of the reference numerals in the drawings indicating elements of any cartridge or elements provided corresponding to any cartridge , C, K may be omitted.

  FIG. 1 is a cross-sectional view of the image forming apparatus 1 viewed from the non-driving side. The front side of the sheet is the non-driving side of the image forming apparatus 1, the right side of the sheet is the front of the image forming apparatus 1, and the back side of the sheet is the image forming apparatus 1. Drive side. In the apparatus main body 2, first, second, third, and fourth cartridges PY, PM, PC, and PK are arranged in the horizontal direction. As will be described in detail later, a rotational driving force (rotational force) is transmitted to the cartridge P from a drive output unit provided in the apparatus main body 2. A bias voltage (charging bias, developing bias, etc.) is supplied to the cartridge P from the apparatus body 2.

  FIG. 3 is a cross-sectional view of the cartridge P of this embodiment as viewed from the non-driving side. As shown in FIG. 3, the cartridge P includes a photoconductor unit 8 and a developing unit 9. The photoconductor unit 8 includes a photoconductor drum (hereinafter also simply referred to as “drum”) 4 that is a drum-type (cylindrical) photoconductor as an image carrier, and charging as process means acting on the drum 4. Means and cleaning means. Further, the developing unit 9 has a developing unit that develops the electrostatic latent image on the drum 4. The first, second, third, and fourth cartridges PY, PM, PC, and PK are respectively stored in the developer storage portion 49 formed in the developing frame 29 with yellow, magenta, cyan, and black as developers. Contains toner of each color. The first, second, third, and fourth cartridges PY, PM, PC, and PK form yellow, magenta, cyan, and black toner images (developer images) on the surface of the drum 4, respectively. . The cartridge P will be described in more detail later.

  In FIG. 1, a laser scanner unit LB as an exposure unit is provided above the first, second, third, and fourth cartridges PY, PM, PC, and PK. The laser scanner unit LB outputs laser light Z corresponding to image information of each color image of yellow, magenta, cyan, and black, and emits it to each cartridge PY, PM, PC, PK. The laser light Z passes through the exposure window 10 of the cartridge P and scans and exposes the surface of the drum 4.

  In FIG. 1, an intermediate transfer belt unit 11 as a transfer device for transferring a toner image to a recording medium S is provided below the first, second, third, and fourth cartridges PY, PM, PC, and PK. It has been. The intermediate transfer belt unit 11 includes a driving roller 13, a secondary transfer counter roller 14, and a tension roller 15, and an intermediate transfer member serving as an intermediate transfer member formed of an endless belt having flexibility on these rollers. A belt 12 is stretched over. In FIG. 1, the lower surface of the drum 4 is in contact with the upper surface of the intermediate transfer belt 12. A contact portion between the drum 4 and the intermediate transfer belt 12 is a primary transfer portion N1. On the inner peripheral side of the intermediate transfer belt 12, primary transfer rollers 16Y, 16M, 16C, and 16K, which are roller-shaped primary transfer members serving as primary transfer means, are positioned opposite the drums 4Y, 4M, 4C, and 4K. Is provided. Further, on the outer peripheral side of the intermediate transfer belt 12, a secondary transfer roller 17 that is a roller-like secondary transfer member as a secondary transfer unit is disposed at a position facing the secondary transfer counter roller 14. A contact portion between the intermediate transfer belt 12 and the secondary transfer roller 17 is a secondary transfer portion N2.

  In FIG. 1, a feeding unit 18 is provided below the intermediate transfer belt unit 11. The feeding unit 18 includes a paper feeding tray 19 in which recording media S are stacked and accommodated, and a paper feeding roller 20.

  In FIG. 1, a fixing unit 21 as a fixing unit and a discharge unit 22 are provided on the upper left side in the apparatus main body 2. In FIG. 1, the upper surface of the apparatus main body 2 is a discharge tray 23 on which the recording medium S discharged from the apparatus main body 2 is stacked.

  As will be described in detail later, the cartridge P is configured to be detachable from the apparatus main body 2 via a cartridge tray 60 that can be pulled out. FIG. 2A shows a state in which the cartridge tray 60 is pulled out from the apparatus main body 2. FIG. 2B shows a state where the cartridge tray 60 and the front door 3 are removed in order to make the inside of the apparatus main body 2 easier to see.

[Removable cartridge configuration]
Next, the attaching / detaching operation of the cartridge P to the apparatus main body 2 will be described. FIG. 16 is a cross-sectional view of the image forming apparatus 1 showing a state in which the cartridge tray 60 is pulled out from the apparatus main body 2 and the cartridge P is detachable. FIG. 17 is a cross-sectional view of the image forming apparatus 1 illustrating the operation of attaching and detaching the cartridge P to the cartridge tray 60.

  A cartridge tray 60 in which the cartridge P can be mounted is provided in the apparatus main body 2. As shown in FIG. 16, the cartridge tray 60 is configured to be linearly movable (push / pull out) in the G1 and G2 directions which are substantially horizontal with respect to the apparatus main body 2. The cartridge tray 60 can take a mounting position in the apparatus main body 2 and a drawing position pulled out from the mounting position.

  First, the mounting operation of the cartridge P to the apparatus main body 2 will be described. When the front door 3 is opened and the cartridge tray 60 is moved in the direction of the arrow G1 in FIG. 16, the cartridge tray 60 is moved to the drawer position. In this state, the cartridge P is mounted and held on the cartridge tray 60 from the direction of the arrow H1 in FIG. The cartridge tray 60 holding the cartridge P is moved in the direction of arrow G2 in FIG. 16, and the cartridge tray 60 is moved to the mounting position in the apparatus main body 2. Then, by closing the front door 3, the mounting operation of the cartridge P to the apparatus main body 2 is completed.

  Next, the removal of the cartridge P from the apparatus main body 2 will be described. The cartridge tray 60 is moved to the drawer position in the same manner as the mounting operation of the cartridge P to the apparatus main body 2 described above. In this state, the cartridge P is removed in the direction of the arrow H2 in FIG. 17, and the operation of removing the cartridge P from the apparatus main body 2 is completed.

[Image forming operation]
Next, an image forming operation will be described taking a case where a full color image is formed as an example.

  The drum 4 of each cartridge P is rotationally driven at a predetermined peripheral speed (the direction of arrow D in FIG. 3 (counterclockwise)). Further, the intermediate transfer belt 12 is rotationally driven at a peripheral speed corresponding to the peripheral speed of the drum 4 in the forward direction (the direction of arrow C in FIG. 1 (clockwise)) with respect to the rotation of the drum 4. Further, the laser scanner unit LB is driven. In synchronization with the driving of the laser scanner unit LB, the surface of the drum 4 is uniformly charged to a predetermined potential having a predetermined polarity by a charging roller 5 which is a roller-shaped charging member as a charging unit. The laser scanner unit LB scans and exposes the surface of each drum 4 with a laser beam Z according to the image signal of each color. Thereby, an electrostatic latent image (electrostatic image) corresponding to the image signal of the color corresponding to the surface of each drum 4 is formed. This electrostatic latent image is developed as a toner image by the developing unit 9. The developing unit 9 carries and conveys toner by a developing roller 6 as a developer carrying member that is rotationally driven at a predetermined peripheral speed (in the direction of arrow E (clockwise) in FIG. 3). Supply to the image. The developing roller 6 is coated with toner as a developer by a developing blade 31 (FIG. 3) as a developer regulating member constituting the developing means.

  By such an electrophotographic image forming process, a yellow toner image corresponding to the yellow component of the full-color image is formed on the drum 4Y of the first cartridge PY. Then, the yellow toner image is primarily transferred onto the intermediate transfer belt 12 by the action of the primary transfer roller 16Y in the primary transfer portion N1Y. Thereafter, toner images corresponding to the respective color components of magenta, cyan, and black are formed on the drums 4M, 4C, and 4K of the second cartridge PM, the third cartridge PC, and the fourth cartridge PK. Then, these toner images are sequentially primary-superimposed on the toner images already transferred onto the intermediate transfer belt 12 in a superimposed manner. In this way, four colors of superimposed toner images of yellow, magenta, cyan, and black are formed on the intermediate transfer belt 12.

  On the other hand, the recording medium S is separated and fed one by one at a predetermined control timing. The recording medium S is introduced into the secondary transfer portion N2 at a predetermined control timing. As a result, in the process in which the recording medium S is transported through the secondary transfer portion N2, the four color superimposed toner images on the intermediate transfer belt 12 are sequentially and collectively transferred onto the surface of the recording medium S. .

  The recording medium S on which the toner image is transferred is heated and pressed by a fixing roller and a pressure roller provided in the fixing unit 21 to fix the toner image thereon, and then is discharged to the discharge tray 23. Is done.

  The toner remaining on the drum 4 after the primary transfer (primary transfer residual toner) is scraped off and removed from the rotating drum 4 by a cleaning blade 7 (FIG. 3) as a cleaning means, and a waste developer storage section. 27 (FIG. 3). Further, the toner (secondary transfer residual toner) remaining on the intermediate transfer belt 12 after the secondary transfer is removed and collected by an intermediate transfer member cleaning unit (not shown).

[Cartridge configuration]
FIG. 4 is an assembled perspective view of the cartridge P of this embodiment as viewed from the drive side. FIG. 5 is an assembled perspective view of the cartridge P of this embodiment as viewed from the non-driving side. FIG. 7 is an exploded view of the drive connecting portion of the cartridge P of this embodiment as viewed from the drive side. FIG. 8 is an exploded view of the drive connecting portion of the cartridge P of this embodiment as viewed from the non-drive side.

  The cartridge P has a drum 4 and process means acting on the drum 4. In this embodiment, the cartridge P has the following means as process means. First, a charging roller 5 as charging means for charging the drum 4 is provided. Further, a developing roller 6 as developing means for developing the latent image formed on the drum 4 is provided. Further, the cleaning blade 7 is a cleaning unit for removing the residual developer remaining on the surface of the drum 4. The cartridge P is divided into the photosensitive unit 8 and the developing unit 9 as described above.

[Configuration of photoconductor unit]
As shown in FIGS. 3 to 5, the photosensitive unit 8 includes a drum 4, a charging roller 5, a cleaning blade 7, a cleaning container 26, a waste developer storage portion 27 formed in the cleaning container 26, and a cartridge cover member 24. , 25 and the like. The cartridge cover member includes a drive side cartridge cover member 24 and a non-drive side cartridge cover member 25.

  The drum 4 is rotatably supported by cartridge cover members 24 and 25 as end members provided at both ends of the cartridge P in the longitudinal direction. Here, the direction corresponding to the rotational axis direction of the drum 4 for the cartridge P is defined as the longitudinal direction. The cartridge cover members 24 and 25 are fixed to a cleaning container (cleaning frame) 26 at both ends in the longitudinal direction of the cartridge P. As shown in FIG. 4, a coupling member 4 a for transmitting a rotational driving force to the drum 4 is provided on one end side in the rotation axis direction of the drum 4. The coupling member 4a of each cartridge PY, PM, PC, PK is engaged with drum drive output members 61Y, 61M, 61C, 61K provided in the apparatus main body 2 shown in FIG. A rotational driving force from a driving motor (not shown) provided in the apparatus main body 2 as an external driving source is transmitted to the drum 4 via the drum driving output member 61 to the coupling member 4a. The coupling member 4a engages with the drum drive output member 61 when the cartridge P is mounted on the apparatus main body 2 as described above.

  The charging roller 5 is supported by the cleaning container 26 so as to come into contact with the drum 4 and be rotated by the rotation of the drum 4. Further, the cleaning blade 7 is supported by the cleaning container 26 so as to contact the peripheral surface of the drum 4 with a predetermined pressure. The transfer residual toner removed from the peripheral surface of the drum 4 by the cleaning unit 7 is stored in a waste developer storage unit 27 in the cleaning container 26.

  4 and 5, the driving side cartridge cover member 24 and the non-driving side cartridge cover member 25 are respectively provided with a driving side developing unit support portion 24a for rotatably supporting the developing unit 9. A non-driving side developing unit support 25a is provided.

[Development unit configuration]
As shown in FIGS. 4, 5, 7, and 8, the developing unit 9 includes a developing roller 6, a developing blade 31, a developing frame 29, a developer container 49 formed in the developing frame 29, a bearing The member 45, the developing cover member 32, etc.

  As shown in FIG. 7, the bearing member 45 is fixed to the outside of the developing device frame 29 on one end side (drive side) of the cartridge P in the longitudinal direction. The bearing member 45 rotatably supports one end side (drive side) of the developing roller 6 in the rotation axis direction. The developing roller 6 has a developing roller gear (developer carrier gear) 69 at one end (drive side) in the rotation axis direction. As will be described in detail later, the developing roller gear 69 is fitted and fixed to a shaft portion 6a extending to one end side (driving side) of the developing roller 6 in the rotation axis direction, and is collinear with the developing roller 6 (coaxially). ) To rotate together. In other words, the bearing member 45 rotatably supports the developing roller gear 69 via the developing roller 6. The other end side (non-driving side) of the developing roller 6 in the rotation axis direction is rotatably supported by the developing frame 29. The bearing member 45 rotatably supports an idler gear 68 for transmitting a rotational driving force to the developing roller gear 69.

  As the drive connecting portion, the following members are provided between the bearing member 45 and the drive side cartridge cover member 24 from the bearing member 45 toward the drive side cartridge cover member 24. First, an idler gear 68 is provided. Next, a spring 70 which is a part of the drive coupling mechanism and a clutch coupling 71 which is a part of the drive coupling mechanism are provided. Next, a release cam 72 which is a part of the release mechanism, and a release lever 73 as an action member which is a part of the release mechanism are provided. Next, a development input coupling 74 which is a development drive input member is provided. Finally, a developing cover member 32 is provided. These members are provided so as to be collinear (coaxial) with the development input coupling 74. The developing cover member 32 is fixed to the outside of the bearing member 45 in the longitudinal direction of the cartridge P. The developing cover member 32 is configured to cover the developing roller gear 69, the idler gear 68, the clutch coupling 71, and the developing input coupling 74. As will be described in detail later, the developing cover member 32 covers at least a part of the drive train from the drive input unit to the developer carrier, and supports at least one of the plurality of gears of the drive train. It is an example of a member.

  Furthermore, as shown in FIGS. 4 and 7, the developing cover member 32 is provided with a cylindrical portion 32 b. And the release lever 73 protrudes from the lever opening part 32c which is an opening part formed in the outer peripheral part of the cylindrical part 32b. Further, a development input, which is a drive input unit to which a rotational driving force is input from an external drive source, is provided from a coupling opening 32d that is an opening formed on the inner side (center) in the radial direction of the end surface of the cylindrical part 32b. The drive input part 74b of the coupling 74 is exposed. The drive input part 74b of each cartridge PY, PM, PC, PK is engaged with the development drive output members 62Y, 62M, 62C, 62K provided in the apparatus main body 2 shown in FIG. Then, a rotational driving force from a driving motor (not shown) provided in the apparatus main body 2 as an external driving source is transmitted to the driving input unit 74b via the development driving output member 62. The drive input portion 74b engages with the development drive output members 62Y, 62M, 62C, and 62K when the cartridge P is mounted on the apparatus main body 2 as described above.

  The rotational driving force input from the apparatus main body 2 to the development input coupling 74 is transmitted to the clutch coupling 71 that meshes with the development input coupling 74, and is further transmitted to the idler gear 68 that meshes with the clutch coupling 71. Then, driving is transmitted to the developing roller gear 69 and the developing roller 6 through the idler gear 68.

  In the present embodiment, the drive connection mechanism and the release mechanism constitute a connection release mechanism that switches the state of connection or release of drive transmission from the drive input unit to a plurality of gears (gear trains).

  The developing roller gear 69, idler gear 68, drive coupling mechanism, release mechanism, etc. will be described in detail later.

[Assembly of photoconductor unit and developing unit]
Next, the assembly of the photosensitive unit 8 and the developing unit 9 will be described with reference to FIGS. When the developing unit 9 and the photosensitive unit 8 are assembled, the outer diameter portion of the cylindrical portion 32b of the developing cover member 32 is connected to the driving side developing unit support portion 24a of the driving side cartridge cover member 24 on one end side in the longitudinal direction of the cartridge P. 32a is fitted. Then, on the other end side in the longitudinal direction of the cartridge P, a projecting portion 29 b that projects from the developing frame 29 is fitted into the non-driving side developing cartridge support portion 25 a of the non-driving side cartridge cover member 25. Thus, the developing unit 9 is supported so as to be rotatable with respect to the photosensitive unit 8.

  Here, the rotation center of the developing unit 9 with respect to the photosensitive unit 8 is defined as an axis X. The axis X is a line connecting the center of the driving side developing unit support 24a and the center of the non-driving side developing cartridge support 25a.

[Development unit attitude]
Next, the posture of the developing unit will be described with reference to FIGS. The developing unit 9 is urged by a pressure spring 95 that is an elastic member serving as an urging unit, and is rotated about an axis X so that the developing roller 6 contacts the drum 4. That is, the developing unit 9 is pressed in the direction indicated by the arrow G in FIG. 3 by the urging force of the pressurizing spring 95, and the moment in the direction indicated by the arrow H in the drawing acts around the axis X. Thereby, the developing roller 6 can contact the drum 4 with a predetermined pressure.

  FIG. 6 is a side view of the cartridge P as viewed from the drive side. In FIG. 6, illustration of some components is omitted for the sake of explanation. When the cartridge P is mounted on the apparatus main body 2, the photosensitive unit 8 is positioned and fixed on the apparatus main body 2. FIG. 6A shows a state where the drum 4 and the developing roller 6 are in contact with each other. The state of the developing unit 9 at this time is referred to as a contact state. This state is set during the developing operation. FIG. 6B shows a state where the drum 4 and the developing roller 6 are separated from each other. The state of the developing unit 9 at this time is a separated state. The developing unit 9 is rotated by an angle θ2 about the axis X in the direction of the arrow K in FIG. 6B by a force from an action portion (not shown) provided in the apparatus body 2. The At this time, the drum 4 and the developing roller 6 are separated from each other by a distance ε2. This state is set when the cartridge P is not used in the apparatus main body 2 such as when waiting for an image forming operation. By controlling the operation of the action portion provided in the apparatus main body 2, the contact state and the separation state of the cartridge P are switched.

[Configuration of drive connecting part]
Next, the configuration of the drive connecting portion will be described in more detail with reference to FIGS.

  As described above, the bearing member 45 rotatably supports the idler gear 68 and the developing roller 6. A first bearing portion 45q (cylindrical inner surface) as a first support portion (developer carrier support portion) provided on the bearing member 45 is rotatable with the outer periphery of a shaft portion 6a as a support receiving portion of the developing roller 6. The developing roller 6 is rotatably supported. A developing roller gear 69 is fitted to the shaft portion 6 a of the developing roller 6. In other words, the first bearing portion 45q serving as the first support portion rotatably supports the developing roller gear 69 via the shaft portion 6a of the developing roller 6. Further, a second bearing portion 45p (cylindrical outer surface) as a second support portion (first idler gear support portion) provided in the bearing member 45 is an inner portion of the first cylindrical portion 68p as a first support receiving portion of the idler gear 68. The idler gear 68 is rotatably supported by engaging with the circumference. The first cylindrical portion 68p is provided at one end of the idler gear 68 in the rotation axis direction. As a result, the rotational driving force is transmitted from the idler gear 68 to the developing roller 6 via the developing roller gear 69. Further, the engagement protrusions 68a (four in this embodiment) of the idler gear 68 are slidably engaged with the corresponding engagement holes 71b of the clutch coupling 71, so that the idler gear 68 and the clutch coupling 71 are connected. It is configured to rotate integrally on the same straight line (coaxial).

  FIG. 9 shows the configuration of the development input coupling 74 and the clutch coupling 71. A hole 71m is provided in the center of the clutch coupling 71 in the radial direction. The hole 71m is rotatably engaged with the first small-diameter cylindrical portion 74m of the development input coupling 74. As a result, the clutch coupling 71 is supported so as to be rotatable with respect to the development input coupling 74. As shown in FIG. 7, a release cam 72 is disposed between the clutch coupling 71 and the development input coupling 74. As shown in FIG. 10, the release cam 72 is configured in a substantially ring shape and has an outer peripheral surface 72i. The developing cover member 32 has an inner peripheral surface 32i. The release cam 72 is supported by the developing cover member 32 with the outer peripheral surface 72 i slidably engaged with the inner peripheral surface 32 i of the developing cover member 32. The developing cover member 32 has a guide 32h as a guide portion, and the release cam 72 has a guide groove 72h as a guided portion. The guide 32h of the developing cover member 32 is slidably engaged with the guide groove 72h of the release cam 72. Since the guide 32h and the guide groove 72h are engaged, the release cam 72 is slidable only in the direction of the arrow M and the arrow N in the figure along the axis X direction with respect to the developing cover member 32. It has a configuration.

  FIG. 11 is a cross-sectional view of the drive connecting portion. FIG. 11A shows a state in which a claw 71a of a clutch coupling 71, which will be described later, and a claw 74a of a development input coupling 74 are engaged with each other. FIG. 11B shows a state in which the claw 71a of the clutch coupling 71 and the claw 74a of the development input coupling 74 are separated from each other. The developing cover member 32 is rotatable with the outer periphery of the second cylindrical portion 68q as the second support receiving portion of the idler gear 68 at the inner diameter portion 32q as the third support portion (second idler gear support portion) provided thereon. The idler gear 68 is rotatably supported. The second cylindrical portion 68q is provided at the end of the idler gear 68 opposite to the first cylindrical portion 68p in the rotational axis direction. Further, the second small-diameter cylindrical portion 74k of the development input coupling 74 and the hole 68k of the idler gear 68 are rotatably engaged. Further, the cylindrical portion 74p of the development input coupling 74 and the hole portion 32p of the development cover member 32 are engaged with each other in a rotatable manner. That is, the development input coupling 74 is supported by the idler gear 68 and the development cover member 32 so as to be rotatable at both ends in the rotational axis direction. Further, the second bearing portion 45p of the bearing member 45, the inner diameter portion 32q of the developing cover member 32, and the hole portion 32p of the developing cover member 32 are arranged so as to be collinear (coaxial) with the axis X. That is, the development input coupling 74 is supported with respect to the development unit 9 so as to be rotatable about an axis X that is a rotation center of the development unit 9 with respect to the photosensitive unit. Further, as described above, the first small diameter cylindrical portion 74m of the development input coupling 74 and the hole 71m of the clutch coupling 71 are engaged (FIG. 9). As a result, the clutch coupling 71 is supported with respect to the developing unit 9 so as to be rotatable about the axis X. Further, the guided surface 73 s of the release lever 73 is in contact with the guide surface 74 s of the development input coupling 74. As a result, the release lever 73 is restricted from moving in the direction of the axis X. As will be described in detail later, the claw 71a of the clutch coupling 71 and the claw 74a of the development input coupling 74 are in a state where they are engaged with each other (FIG. 11 (a)) and are separated from each other. Is switched to the state (FIG. 11B).

  FIG. 12 shows the configuration of the release cam 72 and the release lever 73. The release cam 72 has an abutting portion (slope) 72a, a cylindrical inner surface 72e, and a substantially central opening 72d. The release lever 73 includes a contact portion (slope) 73a, an outer peripheral surface 73e, and a substantially central opening 73d. The contact portion 72a of the release cam 72 and the contact portion 73a of the release lever 73 are configured to be in contact with each other. The cylindrical inner surface 72e of the release cam 72 and the outer peripheral surface 73e of the release lever 73 are engaged with each other so as to be rotatable. Furthermore, the outer peripheral surface 72i of the release cam 72, the cylindrical inner surface 72e of the release cam 72, and the outer peripheral surface 73e of the release lever 73 are arranged so that their rotational axes are on the same straight line (coaxial). As described above, the outer peripheral surface 72 i of the release cam 72 is configured to engage with the inner peripheral surface 32 i of the developing cover member 32. Further, the outer peripheral surface 72 i of the release cam 72 and the inner peripheral surface 32 i of the developing cover member 32 are arranged so as to be collinear (coaxial) with the axis X. That is, the release lever 73 is supported with respect to the developing unit 9 via the release cam 72 and the developing cover member 32 so as to be rotatable about the axis X.

  FIG. 13 shows the configuration of the drive connecting portion and the drive side cartridge cover member 24. The release lever 73 has a force receiving portion 73b. The force receiving portion 73 b is engaged with the engaging portion 24 d of the driving side cartridge cover member 24 and receives force from the driving side cartridge cover member 24. The force receiving portion 73 b protrudes from a lever opening 32 c provided in a part of the cylindrical portion 32 b of the developing cover member 32 and engages with the engaging portion 24 d of the driving side cartridge cover member 24. Since the engaging portion 24d and the force receiving portion 73b are engaged, the release lever 73 is restricted so as not to move relative to the drive side cartridge cover member 24 around the axis X. Thus, the release lever 73 is arranged so that the force receiving portion 73b that engages with the engaging portion 24d of the drive side cartridge cover member 24 protrudes from the lever opening portion 32c.

[Operation of drive connecting part]
With reference to FIGS. 6 to 15, the operation of the drive connecting portion according to the posture change of the developing unit 9 to the contact state and the separation state will be described.

  First, the operation of the drive connecting portion when the developing unit 9 is in contact (FIG. 6A) will be described. FIG. 14A schematically shows the state of the drive connecting portion when the developing unit 9 is in the contact state. FIG. 14B is a perspective view of the configuration of the drive connecting portion in that state. In FIG. 14, illustration of some components is omitted for the sake of explanation. In FIG. 14A, a pair of the development input coupling 74 and the clutch coupling 71 and a pair of the release cam 72 and the release lever 73 are shown separately. In FIG. 14B, only a part of the developing cover member 32 including the guide 32h is displayed.

  There is a gap e between the contact portion 72 a of the release cam 72 and the contact portion 73 a of the release lever 73. At this time, the claw 74a of the development input coupling 74 and the claw 71a of the clutch coupling 71 are engaged with each other with an engagement amount q so that drive transmission is possible. Further, as described above, the clutch coupling 71 is engaged with the idler gear 68 (FIG. 11). Therefore, the rotational driving force input from the apparatus main body 2 to the development input coupling 74 is transmitted to the idler gear 68 via the clutch coupling 71. As a result, the developing roller gear 69 and the developing roller 6 are driven.

  Next, when the developing unit 9 is rotated from the contact state (FIG. 6A) by the angle θ2 about the axis X in the direction of the arrow K and moved to the separated state (FIG. 6B). The operation of the drive connecting portion will be described. FIGS. 15A and 15B are views similar to FIGS. 14A and 14B when the developing unit 9 is in the separated state, respectively.

  When the developing unit 9 is rotated by an angle θ2, the release cam 72 and the developing cover member 32 incorporated in the developing unit 9 are rotated in the direction of the arrow K in the drawing by an angle θ2 in conjunction with the rotation of the developing unit 9. To do. On the other hand, the release lever 73 is incorporated in the developing unit 9, but its force receiving portion 73b is engaged with the engaging portion 24d of the driving side cartridge cover member 24 as shown in FIG. Therefore, the position of the contact portion 73a of the release lever 73 does not change, and the release lever 73 is not interlocked with the rotation of the developing unit 9. Therefore, when the release cam 72 rotates in the direction of arrow K in the figure, the contact portion 72a of the release cam 72 receives a reaction force from the contact portion 73a of the release lever 73. Further, as described above, the release cam 72 is movable only in the direction of the axis X in the direction of the arrow M and the arrow N in the drawing, with the guide groove 72h engaging the guide 32h of the developing cover member 32. It is regulated. Therefore, when the contact portion 73a of the release lever 73 applies a reaction force to the contact portion 72a of the release cam 72, the release cam 72 slides in the direction of arrow N in the figure by the movement amount p. Further, in conjunction with the movement of the release cam 72 in the direction of arrow N in the figure, the pressing surface 72 c of the release cam 72 presses the non-pressing surface 71 c of the clutch coupling 71. As a result, the clutch coupling 71 slides in the direction of arrow N in the figure by the movement amount p against the pressing force of the spring 70. At this time, since the movement amount p is larger than the engagement amount q between the claw 74a of the development input coupling 74 and the claw 71a of the clutch coupling 71, the claw 74a of the development input coupling 74 and the claw 71a of the clutch coupling 71 Is disengaged. As a result, the development input coupling 74 continues to rotate by receiving a rotational driving force from the apparatus main body 2, while the clutch coupling 71 stops. As a result, the rotation of the idler gear 68, the developing roller gear 69, and the developing roller 6 stops.

  Next, the operation of the drive connecting portion when the developing unit 9 changes from the separated state to the contact state will be described. This operation is the reverse of the operation from the contact state of the developing unit 9 to the separated state.

  As shown in FIG. 15, when the developing unit 9 is in the separated state (FIG. 6B), the drive connecting portion engages the claw 74 a of the development input coupling 74 and the claw 71 a of the clutch coupling 71. Is in a released state. From this state, when the developing unit 9 is gradually rotated in the direction of arrow H in the figure and the developing unit 9 is rotated by an angle θ2, the clutch coupling 71 is moved in the direction of arrow M in the figure by the pressing force of the spring 70. . Then, the claw 74a of the development input coupling 74 and the claw 71a of the clutch coupling 71 are engaged with each other. Thus, as described above, the rotational driving force input from the apparatus main body 2 to the development input coupling 74 is transmitted to the development roller 6 via the clutch coupling 71, the idler gear 68, and the development roller gear 69.

[Configuration of developing roller gear and idler gear]
The configuration of the idler gear 68 and the developing roller gear 69 will be described in more detail with reference to FIGS.

  FIG. 18A is a perspective view of the developing roller gear 69. The developing roller gear 69 includes a gear portion (tooth) 69a, a drive transmission surface (fitting surface) 69b, an inclination suppression rib 69c, and a cylindrical support portion 69d.

  FIG. 18B is an enlarged perspective view showing the gear portion 69 a of the developing roller gear 69. As shown in FIG. 18B, the tooth surface 69a3 of the gear portion 69a of the developing roller gear 69 has a thickness at the center portion in the tooth width direction rather than a thickness at an end portion in the tooth width direction (rotation axis direction). It has a crowning shape that becomes larger. That is, the thickness 691 of the tooth surface 69a3 of the gear portion 69a of the developing roller gear 69 is t1, and the thickness of the center portion 69a2 of the tooth width direction is t2. At this time, the tooth surface 69a3 of the gear portion 69a of the developing roller gear 69 has a crowning shape with a crowning amount c such that t2−t1 = 2c (> 0).

  FIG. 19B is a vertical sectional view of the developing roller gear 69 in a state where the developing roller 6 and the developing roller gear 69 are fitted (FA-FA cross section in FIG. 19A). A hatched area in FIG. 19B shows the shaft portion 6 a of the developing roller 6. As shown in FIG. 19B, the cylindrical support portion 69d of the developing roller gear 69 and the shaft portion 6a of the developing roller 6 are fitted. Further, the drive transmission surface 69b of the developing roller gear 69 is a surface for transmitting the rotational driving force to the developing roller 6, and the rotational driving force is brought into contact with the driven transmission surface 6a1 of the shaft portion 6a of the developing roller 6. Can be transmitted to the developing roller 6. The position of the end portion 69b1 of the drive transmission surface 69b in the rotation axis U direction of the developing roller gear 69 is located between the tooth widths W of the gear portion 69a. Further, the developing roller gear 69 is formed to extend from the end portion 69b1 of the drive transmission surface 69b to the developing roller 6 side (in the direction of arrow L in FIG. 19B) in the rotation axis U direction of the developing roller gear 69. An inclination restraining rib 69c is provided. The inclination restraining rib 69c is formed between the end portion 69b1 of the drive transmission surface 69b and the end portion 6a2 of the driven transmission surface 6a1 of the developing roller 6 in the direction of the rotation axis U of the developing roller gear 69. Furthermore, the rib contact surface 69c1 of the inclination suppressing rib 69c is formed to be flush with the drive transmission surface 69b in order to contact the driven transmission surface 6a1 of the developing roller 6.

  FIG. 19A is a front view of the developing roller gear 69 viewed from one end side (the developing roller 6 side) of the developing roller gear 69 in the rotation axis direction. Here, a ridge line where the drive transmission surface 69b of the developing roller gear 69 intersects the cylindrical support portion 69d is a corner portion 69e, and a center line of the drive transmission surface 69b is m. As shown in FIG. 19A, the inclination suppression rib 69c is arranged symmetrically with respect to the center line m with a certain distance a between the corner 69e in the direction orthogonal to the center line m.

  The drive transmission surface 69 b and the inclination suppression rib 69 c prevent the rotation axis U of the developing roller gear 69 from being inclined with respect to the rotation axis of the developing roller 6. The position of the end portion 69b1 of the drive transmission surface 69b is located between the tooth widths W of the gear portion 69a, and the tilt suppressing rib having the above-described configuration is arranged from the end portion 69b1 to the arrow L direction side in FIG. 69c is arranged. As a result, the volume of the tooth bottom of the gear portion 69a is reduced as much as possible, and a reduction in the dimensional accuracy of the gear portion 69a due to molding sink marks of the developing roller gear 69 is suppressed.

  In the present embodiment, there are two inclination suppression ribs 69c, but the number is not limited to this, and may be one or three or more, for example. Preferably, as in the present embodiment, the configuration is symmetric with respect to the center line m, and a certain distance a is spaced from the corner 69e.

The specification of a suitable developing roller gear 69 in the present embodiment is as follows.
Material: Resin material with good slidability such as POM. In addition, a wide range of arbitrary materials can be applied by applying a lubricant such as grease.
Gear shape: Spur gear, helical gear, etc. are optional, but in this embodiment, a spur gear is used.
Module: Arbitrary, but 0.5 in this embodiment.
Number of teeth: Arbitrary, but 20 teeth are used in this embodiment.
Tooth width: Arbitrary, but 3 mm in this embodiment.
Crowning amount: 0.01 mm to 0.1 mm in this embodiment (c = 0.01 to 0.1 mm in FIG. 18B). Further details will be described later.

  FIG. 20 shows the configuration of the idler gear 68. The idler gear 68 has a gear part (tooth) 68b, a first cylindrical part 68p, and a second cylindrical part 68q. The gear portion 68 b meshes with the gear portion 69 a of the developing roller gear 69. Further, as described above, the first cylindrical portion 68p is engaged with the second bearing portion 45p of the bearing member 45, and the second cylindrical portion 68q is engaged with the inner diameter portion 32q of the developing cover member 32 (FIGS. 7 and 7). 8).

[Drive transmission between idler gear and developing roller gear]
Next, with reference to FIGS. 21 to 23, the state of transmission of drive from the idler gear 68 to the developing roller gear 69 will be described.

  FIG. 21 is a plan view of the arrangement of the drive train from the development input coupling 74 (more specifically, the drive input portion 74b) to the development roller 6 as seen in the direction intersecting the longitudinal direction of the cartridge P. In FIG. 21, illustration of some members is omitted for explanation. 22A and 22B show the arrangement of the bearing member 45 and the developing cover member 32 as viewed from the outside (drive side) in the longitudinal direction of the cartridge P. FIG. As will be described later, FIGS. 22A and 22B show states in which the relationship between the idler gear support center of the bearing member 45 and the idler gear support center of the developing cover member 32 is different. FIGS. 22C and 22D show meshing states of the idler gear 68 and the developing roller gear 69 corresponding to FIGS. 22A and 22B, respectively.

  As shown in FIG. 21, the bearing member 45 rotatably supports the shaft portion 6a of the developing roller 6 and the idler gear 68. The developing cover member 32 supports the idler gear 68 and the developing input coupling 74 in a rotatable manner. The development input coupling 74 is connected to a clutch coupling 71 (not shown in FIG. 21), and is indicated by H in the drawing by a development drive output member 62 (FIG. 2B) provided in the apparatus main body 2. A rotational driving force in the direction is input. The idler gear 68 connected to the development input coupling 74 via the clutch coupling 71 is rotationally driven in the H direction in the figure. The idler gear 68 that is rotationally driven in the H direction in the figure transmits a force to the developing roller gear 69, and rotates the developing roller gear 69 in the J direction in the figure. The developing roller 6 fitted with the developing roller gear 69 is rotationally driven in the J direction in the figure.

  21 and 22C, the gear portion 68b of the idler gear 68 and the gear portion 69a of the developing roller gear 69 are engaged with each other. Here, a gear portion that meshes with the gear portion 69a of the developing roller gear 69 in the gear portion 68b of the idler gear 68 is referred to as a meshing gear portion 68g. A gear portion that meshes with the gear portion 68b of the idler gear 68 in the gear portion 69a of the developing roller gear 69 is referred to as a meshing gear portion 69g.

  FIG. 23A is a tangential cross section at the meshing position of the idler gear 68 and the developing roller gear 69 (cross section RA-RA in FIG. 22C), and shows the meshed state of each gear. The hatched area in FIG. 23 indicates the gear portion 68b (including the meshing gear portion 68g) of the idler gear 68. Further, the hatched area of the diagonal lattice in FIG. 23 shows the gear portion 69a (including the meshing gear portion 69g) of the developing roller gear 69. In FIG. 23, the rotation axis V of the idler gear 68 is in a position that cannot be illustrated, but is shown for explanation.

  When the idler gear 68 rotates about the rotation axis V in the direction of arrow H in the figure, the meshing gear portion 68g of the idler gear 68 moves in the tangential direction (direction of arrow K in FIG. 23). At this time, the contact surface 68g1 of the meshing gear portion 68g of the idler gear 68 contacts the contacted surface 69g3 of the meshing gear portion 69g of the developing roller gear 69, and the meshing gear portion 68g of the idler gear 68 presses the meshing gear portion 69g of the developing roller gear 69. To do. Therefore, the meshing gear portion 69g of the developing roller gear 69 is driven in the tangential direction (the direction of arrow E in FIG. 23). Then, the developing roller gear 69 is driven to rotate in the direction of arrow J in the figure around the rotation axis U.

[Effects of crowning shape]
Next, the effect of the crowning shape of the gear portion 69a of the developing roller gear 69 will be described. In the following description, it is assumed that the rotation axis U of the developing roller gear 69 maintains an ideal axis (position, inclination). In FIG. 22, the ideal axis direction is perpendicular to the paper surface. However, for the sake of explanation, the ideal axis line is expressed as a line having an angle.

  First, a phenomenon in which the rotation axis V of the idler gear 68 is inclined with respect to the rotation axis U of the developing roller gear 69 will be described.

  The idler gear 68 is supported at both ends in the rotation axis V direction by the second bearing portion 45p of the bearing member 45 and the inner diameter portion 32q of the developing cover member 32. That is, as shown in FIG. 22A, the straight line S connecting the center position 45p1 of the second bearing portion 45p and the center position 32q1 of the inner diameter portion 32q becomes the rotation axis V of the idler gear 68. As shown in FIG. 22C, when the straight line S is substantially parallel to the rotation axis U of the developing roller gear 69, the rotation axis V of the idler gear 68 is substantially parallel to the rotation axis U of the developing roller gear 69. Accordingly, the idler gear 68 meshes with the developing roller gear 69 in substantially parallel.

  On the other hand, FIG. 22B shows a state in which a straight line S connecting the center position 45p1 of the second bearing portion 45p and the center position 32q1 of the inner diameter portion 32q is inclined with respect to the rotation axis U of the developing roller gear 69 by an angle Δα. Represent. In this case, as shown in FIG. 22D, the rotation axis V of the idler gear 68 is inclined with respect to the rotation axis U of the developing roller gear 69 by an angle Δα. The rotation axis of the idler gear 68 at this time is defined as a rotation axis V ′. In this case, the idler gear 68 meshes with the developing roller gear 69 while being inclined at an angle Δα.

  Such an inclination of the straight line S with respect to the rotation axis U of the developing roller gear 69 may occur when the dimensional accuracy or the assembly accuracy of at least one of the bearing member 45 and the developing cover member 32 is insufficient.

  In the present embodiment, the developing cover member 32 has a lever opening 32c from which the release lever 73 protrudes so as to engage with the restricting portion 24d of the driving side cartridge cover member 24 (FIGS. 13 and 21). . For this reason, for example, as shown in FIG. 27, the rigidity may be reduced as compared with the case of the developing cover member 320 that does not have a lever opening. In the example of FIG. 27, elements having substantially the same functions and configurations as those of the present embodiment are denoted by the same reference numerals. In the example of FIG. 27, the idler gear 68 is supported by the second bearing portion 45p of the bearing member 45 and the inner diameter portion 320q of the developing cover member 32 at both ends in the rotation axis V direction. When the rigidity of the developing cover member 32 is low, the developing cover member 32 is brought into contact with the developing cover member 32 by the meshing force between the developing roller gear 69 and the idler gear 68 at the time of rotation as shown by the arrow F in FIGS. Deformation may occur. As a result, the position of the center position 32q1 of the inner diameter portion 32q is shifted, and the straight line S is inclined by the angle Δα with respect to the rotation axis U of the developing roller gear 69 as shown in FIG. In this case, as described above, the rotation axis V of the idler gear 68 is a rotation axis V ′ inclined by an angle Δα with respect to the rotation axis U of the developing roller gear 69 as shown in FIG. Therefore, the idler gear 68 meshes with the developing roller gear 69 in an inclined state Δα.

  Next, the difference in the meshing state of the gear portion between the state where the inclination of the rotation axis V of the idler gear 68 is not generated with respect to the rotation axis U of the developing roller gear 69 and the state where the inclination of the angle Δα is generated will be described. To do.

  First, as a comparative example, the case of the developing roller gear 690 having no crowning shape as shown in FIG. 28 will be described. FIG. 28A is a perspective view of the developing roller gear 690 of the comparative example, and FIG. 28B is a partially enlarged perspective view of the developing roller gear 690 of the comparative example. The developing roller gear 690 includes a gear portion 690a, a drive transmission surface (fitting surface) 690b, an inclination suppression rib 690c, and a cylindrical support portion 690d. As shown in FIG. 28 (b), the tooth surface 690a3 of the gear portion 690a has a constant thickness t at the tooth width direction end portion 690a1 and the tooth width direction center portion 690a2 of one tooth of the gear portion 690a. Yes. Since the other configuration of the developing roller gear 690 of the comparative example is the same as that of the developing roller gear 69 having the crowning shape of the present embodiment, the description thereof is omitted.

  As shown in FIG. 22A, when the rotation axis V of the idler gear 68 is substantially parallel to the rotation axis U of the developing roller gear 690, the idler gear 68 and the developing roller gear 690 mesh with each other in a substantially parallel state. FIG. 29A shows the meshing state of the eye door gear 68 and the developing roller gear 690 in this case (the RA-RA cross section in FIG. 22C). The hatched area in FIG. 29 (a) has the same meaning as in FIG. 23 (a). As shown in FIG. 29A, when the rotation axis V of the idler gear 68 is not inclined, the contact surface 68g1 of the meshing gear portion 68g of the idler gear 68 and the contacted surface 690g3 of the meshing gear portion 690g of the developing roller gear 690 Contact substantially parallel. Therefore, the tooth contact between the meshing gear portion 68g of the idler gear 68 and the meshing gear portion 690g of the developing roller gear 690 is uniform in the tooth width direction. Accordingly, the surface pressure applied to the contacted surface 690g3 of the meshing gear portion 690g of the developing roller gear 690 is small, and the deformation of the meshing gear portion 690g of the developing roller gear 690 is small. Therefore, vibration generated in the developing roller gear 690 is small, and the developing roller gear 690 can rotate with high accuracy.

  On the other hand, as shown in FIG. 22B, when the rotation axis V ′ of the idler gear 68 is inclined by the angle Δα with respect to the rotation axis U of the developing roller gear 690, the idler gear 68 and the developing roller gear 690 are inclined by the angle Δα. Engage. FIG. 29B shows the meshing state of the eye door gear 68 and the developing roller gear 690 in this case (the RA-RA cross section in FIG. 22D). The hatched area in FIG. 29 (b) has the same meaning as in FIG. 23 (a). As shown in FIG. 29B, when the rotation axis V ′ of the idler gear 68 is inclined at an angle Δα, the contact surface 68g1 of the meshing gear portion 68g of the idler gear 68 and the meshing gear portion 690g of the developing roller gear 690 are covered. The contact surface 690g3 is inclined at an angle Δα. Therefore, the tooth contact between the meshing gear portion 68g of the idler gear 68 and the meshing gear portion 680g of the developing roller gear 690 is the one contact with the end portion 690g1 of the developing roller gear 690 in the tooth width direction first. When it comes into contact, the developing roller gear 690 receives the force from the idler gear 68 only at the end portion 690g1 in the tooth width direction, which is lower in rigidity than the central portion in the tooth width direction of the meshing gear portion 690g of the developing roller gear 690. The deformation of the meshing gear portion 690g is increased. When this deformation becomes large, vibration may occur in the rotation direction of the developing roller gear 690, and the rotation accuracy of the developing roller gear 690 may be reduced. Then, the developing roller 6 receiving the rotational driving force from the developing roller gear 690 may generate vibration in the rotational direction. Then, due to the vibration for each tooth of the gear portion 690a of the developing roller gear 690, uneven development of the electrostatic latent image on the drum 4 by the developing roller 6 occurs, and appears on the image as a horizontal streak of the gear 1 tooth cycle. May cause a reduction in image quality.

  Next, the case of the developing roller gear 69 having a crowning shape on the tooth surface 69a3 of the gear portion 69a of the present embodiment will be described.

  As shown in FIG. 22A, when the rotation axis V of the idler gear 68 is substantially parallel to the rotation axis U of the developing roller gear 69, the idler gear 68 and the developing roller gear 69 mesh with each other in a substantially parallel state. FIG. 23A shows the meshing state of the eye door gear 68 and the developing roller gear 69 in this case (cross-section RA-RA in FIG. 22C).

  As shown in FIG. 23A, when the rotation axis V of the idler gear 68 is not inclined, the central portion 69g2 in the tooth width direction of the meshing gear portion 69g of the developing roller gear 69 is in contact with the meshing gear portion 68g of the idler gear 68. Contact with the contact surface 68g1. This is because, in the developing roller gear 69 having the crowning shape of the present embodiment, the central portion 69a2 in the tooth width direction of the gear portion 69a has a convex shape. Therefore, the tooth contact between the meshing gear portion 68g of the idler gear 68 and the meshing gear portion 69g of the developing roller gear 69 is substantially in the center with respect to the tooth width direction. At this time, the developing roller gear 69 receives a surface pressure from the idler gear 68 at the center portion 69g2 in the tooth width direction, which is stiffer than the end portion 69g1 in the tooth width direction of the meshing gear portion 69g. Therefore, the deformation of the meshing gear portion 69g of the developing roller gear 69 is small, and the vibration generated in the developing roller gear 69 is small. Therefore, the developing roller gear 69 can rotate with high accuracy.

  On the other hand, as shown in FIG. 22B, when the rotation axis V ′ of the idler gear 68 is inclined by the angle Δα with respect to the rotation axis U of the developing roller gear 69, the idler gear 68 and the developing roller gear 69 are inclined by the angle Δα. Engage. FIG. 23B shows the meshing state of the eye door gear 68 and the developing roller gear 69 in this case (the RA-RA cross section in FIG. 22D). The hatched area in FIG. 23 (b) has the same meaning as in FIG. 23 (a). As shown in FIG. 23 (b), even if the idler gear 68 is inclined at an angle Δα, the contact surface 68g1 of the meshing gear portion 68g of the idler gear 68 is the end in the tooth width direction of the meshing gear portion 69g of the developing roller gear 69. The contact surface 69g3 between 69g1 and the central portion 69g2 is contacted. This is because the developing roller gear 69 has a crowning shape in its gear portion 69a. That is, the tooth contact between the meshing gear portion 68g of the idler gear 68 and the meshing gear portion 69g of the developing roller gear 69 is closer to the center in the tooth width direction. As a result, the meshing gear portion 69g of the developing roller gear 69 receives a force from the idler gear 68 at a position closer to the center with respect to the tooth width direction, so that the deformation of the meshing gear portion 69g of the developing roller gear 69 is small, and the developing roller gear. The vibration generated at 69 is small. As described above, by providing the developing roller gear 69 with a crowning shape, even when the rotation axis V of the idler gear 68 has an inclination of the angle Δα, it is possible to suppress a decrease in the rotation accuracy of the developing roller gear 69 and to rotate with high accuracy. Is possible.

  Although the case where the rotation axis V of the idler gear 68 is inclined by the angle Δα with respect to the rotation axis U of the developing roller gear 69 has been described, even when the inclination of the angle −Δα, which is the opposite direction, occurs, the crowning shape The action is similar.

  FIG. 24A is a graph showing a correlation between the amount of inclination of the rotation axis V of the idler gear 68 with respect to the rotation axis U of the developing roller gear 69 and the rotation accuracy of the developing roller gear 68. The horizontal axis represents the amount of inclination of the rotation axis V of the idler gear 68 with respect to the rotation axis U of the developing roller gear 69 (hereinafter also simply referred to as “the amount of inclination of the idler gear 68”). The vertical axis represents the rotational accuracy of the developing roller gear 69 that receives the rotational driving force from the idler gear 68. It shows that rotation accuracy is so high that it goes to the upper side of a graph. In this embodiment, the rotational accuracy of the developing roller gear 69 required to prevent the horizontal streak of the gear 1 tooth period of the developing roller gear 69 from occurring on the image is set to D or more. The case of the developing roller gear 69 having the crowning shape of this embodiment is indicated by a solid line, and the case of the developing roller gear 690 having no crowning shape of the comparative example is indicated by a broken line.

  In the case of the developing roller gear 690 of the comparative example, when the inclination amount of the idler gear 68 is increased, the rotation accuracy of the developing roller gear 69 is greatly reduced. Therefore, the inclination amount of the idler gear 68 for maintaining the required rotational accuracy D or higher must be managed in the range of ± B1.

  On the other hand, in the case of the developing roller gear 69 of the present embodiment, even if the inclination amount of the idler gear 68 is increased, it is possible to reduce the decrease in the rotation accuracy of the developing roller gear 69. As a result, the inclination amount of the idler gear 68 for maintaining the required rotational accuracy D or higher is in the range of ± C1 (| B1 | <| C1 |). As described above, by using the developing roller gear 69 of this embodiment, it is possible to ease the management of the tilt amount of the idler gear 68. That is, the management of the dimensional accuracy of the bearing member 45 and the developing cover member 32 and the assembly accuracy thereof can be eased, and the management cost can be reduced.

  FIG. 24B is a graph showing the correlation between the rigidity of the developing cover member 32 and the rotation accuracy of the developing roller gear 69. The horizontal axis represents the amount of deformation (rigidity) of the inner diameter portion 32q of the developing cover member 32 in the direction of the meshing force between the developing roller gear 69 and the idler gear 68 (arrow F in FIG. 22C). The vertical axis represents the rotational accuracy of the developing roller gear 69 that receives the rotational driving force from the idler gear 68, and the required accuracy is D or higher as described above. The case of the developing roller gear 69 having the crowning shape of this embodiment is indicated by a solid line, and the case of the developing roller gear 690 having no crowning shape of the comparative example is indicated by a broken line.

  As described above, when the development cover member 32 is deformed, the position of the inner diameter portion 32q of the development cover member that supports the idler gear 68 is shifted, and the idler gear 68 is inclined. Further, since the deformation of the developing cover member 32 increases as the rigidity decreases, the inclination amount of the idler gear 68 increases. At this time, in the case of the developing roller gear 690 of the comparative example, when the inclination amount of the idler gear is increased, the rotation accuracy of the developing roller gear 69 is greatly reduced. For this reason, in order to maintain the required rotational accuracy D or higher, a material having rigidity B2 or higher is used for the developing cover member 32, or the developing cover member 32 is increased in thickness or a reinforcing rib is added. I need it.

  On the other hand, in the case of the developing roller gear 69 of the present embodiment, even if the idler gear 68 is inclined due to the deformation of the developing cover member 32, a decrease in the rotation accuracy of the developing roller gear 69 can be reduced. Thereby, in order to maintain the required rotation accuracy D or higher of the developing roller 69, a material having rigidity of B2 or more is used for the developing cover member 32, or an increase in the thickness of the developing cover member 32 or a reinforcing rib is added. You don't have to. That is, the developing cover member 32 has only to have a rigidity of C2 or more (C2 <B2). Thus, by using the developing roller gear 69 of the present embodiment, an inexpensive material with lower rigidity can be used for the developing cover member 32, and the material cost can be reduced. Further, since it is possible to reduce the thickness of the developing cover member 32, to reduce the reinforcing rib, and to provide a notch, the volume of the material used for the developing cover member 32 can be reduced, and the material cost can be reduced. .

  In this embodiment, since the drive connecting portion is connected and released in conjunction with the change in the posture of the developing unit 9, the developing cover member 32 is arranged so that the release lever 73 engaged with the drive side cartridge cover 24 protrudes. A lever opening 32c is provided. As described above, even in the configuration in which the lever opening 32c is provided and the rigidity of the developing cover member 32 is lowered, the rotation accuracy of the developing roller gear 69 can be maintained, and an increase in cost due to the application of a highly rigid material is suppressed. it can.

  In this embodiment, the crowning amount c, which is the convex amount of the central portion 69a2 in the tooth width direction with respect to the thickness of the end portion 69a1 of the gear portion 69a of the developing roller gear 69, is compared to the tooth width W being 3 mm. 0.01 to 0.1 mm. However, the crowning amount c can be freely set according to the dimension of the tooth width. However, if the crowning amount is too small with respect to the tilt amount of the idler gear 68, the tooth contact between the idler gear 68 and the developing roller gear 69 is in a one-sided state. In that case, since the surface pressure from the idler gear 68 is received on the end portion 69g1 side in the tooth width direction of the gear portion 69a having low rigidity of the developing roller gear 69, the rotational accuracy of the developing roller gear 69 is lowered. If the crowning amount is too large, the curvature of the gear portion 69a increases, so that the contact area when the idler gear 68 and the developing roller gear 69 mesh with each other decreases. In this case, since the surface pressure received from the idler gear 69 increases, the gear portions (teeth) 69a of the developing roller gear 68 are likely to be scraped, and the rotational accuracy of the developing roller gear 69 may be reduced. From the above, it is desirable that the crowning amount c is set to an appropriate value according to the specific configuration of the developing unit 9 that implements the present invention.

  In the above-described embodiment, the case where the rotation axis of the developing roller gear maintains an ideal axis and the rotation axis of the idler gear is inclined with respect to the rotation axis of the developing roller gear has been described. However, there is a case where the rotation axis of the idler gear maintains an ideal axis and the rotation axis U of the developing roller gear is inclined with respect to the rotation axis of the idler gear. Also in this case, it can be considered in the same manner as the state in which the rotation axis of the idler gear described in the above-described embodiment is tilted, and thus the description thereof is omitted. The same applies to the case where the rotational axes of both the idler gear and the developing roller gear are tilted and become non-parallel.

  As described above, according to the present embodiment, even if the idler gear 68 and the developing roller gear 69 are engaged with each other while their respective rotation axes are inclined, it is possible to suppress a decrease in drive transmission accuracy. Therefore, the dimensional accuracy and assembly accuracy of the bearing member 45 and the developing cover member 32 can be relaxed, and the bearing member 45 and the developing cover member 32 may be relatively low in rigidity, so that the relatively low rigidity is achieved. And cheap materials can be applied. Therefore, it is possible to reduce the management cost of dimensional accuracy and assembly accuracy and the material cost, and it is possible to reduce the cost of the developing unit and the process cartridge.

Other Embodiments Although the present invention has been described with reference to specific embodiments, the present invention is not limited to the above-described embodiments.

  In the above embodiment, the developing unit is a part of the configuration of the process cartridge, but the present invention is not limited to this. For example, the developing unit may be configured to be detachable from the main body of the image forming apparatus. The developing unit may be a part of the configuration of the apparatus main body that cannot be easily attached to and detached from the apparatus main body of the image forming apparatus. In this case, for example, the developing unit is supplied with developer from a developer bottle. It may be configured.

  Further, in the above-described embodiment, the idler gear is configured to be supported by being engaged with a bearing portion as a support portion provided on the bearing member, but is not limited thereto. For example, a configuration may be adopted in which a bearing portion as a support portion is provided in the developing device frame and the idler gear is supported by being engaged with the bearing portion.

  Further, in the above-described embodiment, the idler gear is configured such that both end portions in the rotation axis direction are rotatably supported by the bearing member and the developing cover member, respectively. That is, in the above-described embodiment, the idler gear is rotatably supported at the both ends in the rotational axis direction by different members. However, the support structure of the idler gear is not limited to this. The idler gear may be configured to be rotatably supported at one end in the rotation axis direction. That is, for example, only the support receiving portion corresponding to the first cylindrical portion of the idler gear in the above-described embodiment may be supported by the support portion provided on the bearing member or the developing device frame. Further, only the support receiving portion corresponding to the second cylindrical portion of the idler gear in the above-described embodiment may be configured to be supported by the support portion provided on the developing cover member. In this case, the rotation axis of the idler gear easily tilts due to the meshing reaction force of the developing roller gear. However, by providing the developing roller gear with a crowning shape as in the above-described embodiment, it is possible to reduce a decrease in the rotation accuracy of the developing roller gear.

  In the above-described embodiment, the developing roller gear is provided with the crowning shape among the plurality of gears (gear trains) of the drive train that transmits the drive to the developing roller provided in the developing unit. However, the present invention is not limited to this. . Speaking of the above-described embodiment, it is sufficient that at least one of the developing roller gear and the idler gear has a crowning shape. That is, only the idler gear may have a crowning shape, or both the idler gear and the developing roller gear may have a crowning shape.

  Further, in the above-described embodiment, the driving connection portion from the developing input coupling to the idler gear is controlled by connecting and releasing the driving connecting portion with respect to the developing roller in conjunction with the posture change of the developing unit. However, the present invention is not limited to this. For example, as shown in FIGS. 25A and 25B, the idler gear 682 is provided with a drive input portion 682c that engages with the development drive output member 62 (FIG. 2B) provided in the apparatus main body 2. Can do. 25A is a perspective view of the idler gear 682, and FIG. 25B is a plan view of a drive train that transmits driving to the developing roller using the idler gear 682. The idler gear 682 includes a gear portion 682b, a first cylindrical portion 682p, and a second cylindrical portion 682q, as in the case of the above-described embodiment. The idler gear 682 may be rotationally driven by inputting a rotational driving force to the drive input unit 682c, and the developing roller gear 69 that meshes with the idler gear 682 may be rotationally driven. In this case, for example, the drive of the development drive output member 62 can be controlled by the control of a drive motor (not shown) provided in the apparatus main body 2, and the drive of the idler gear 682 can be controlled.

  In the above-described embodiment, the idler gear that rotates substantially coaxially with the drive input unit meshes with the developing roller gear that directly transmits the driving to the developing roller, and the developing roller gear is rotationally driven. That is, in the above-described embodiment, the idler gear is the gear closest to the drive input unit in the gear train composed of a plurality of gears of the drive train that transmits the driving force to the developing roller. In the above-described embodiment, the developing roller gear is a gear closest to the developing roller in a gear train composed of a plurality of gears of a driving train that transmits driving force to the developing roller. However, the configuration of the drive train is not limited to this.

  For example, as shown in FIG. 26, when the rotation direction H of the development input coupling 74 is desired to be reversed, a configuration in which the second idler gear 680 is disposed between the idler gear 68 and the developing roller gear 69 can be considered. In the example of FIG. 26, the second idler gear 680 is supported only by the bearing member 45. In this case, by setting the tooth surface of at least one of the idler gear 68, the second idler gear 680, and the developing roller gear 69 to have a crowning shape, the rotational accuracy of the developing roller gear 69 can be improved accordingly. That is, it is only necessary that the tooth surface of at least one gear among the plurality of gears of the drive train that transmits the driving force to the developing roller has a crowning shape. Preferably, in the idler gear 68, the second idler gear 680, and the developing roller gear 69, at least one tooth surface of the gears meshing with each other has a crowning shape. For example, a configuration in which only the second idler gear 680 has a crowning shape, and a configuration in which the idler gear 68 and the developing roller gear 69 have a crowning shape are conceivable.

  Further, the second idler gear may mesh with the third idler gear, and the third idler gear may mesh with the developing roller. As described above, there may be a plurality of gears from the idler gear closest to the drive input unit to the developing roller gear in the driving train that transmits the driving force to the developing roller. That is, the plurality of gears of the drive train that transmits the driving force to the developing roller may include a developing roller gear and a plurality of idler gears that transmit the rotational driving force to the developing roller gear. In addition, by adopting a configuration in which the tooth surface of at least one of the developing roller gear and the plurality of idler gears has a crowning shape, the rotational accuracy of the developing roller gear can be improved accordingly. Preferably, in the developing roller gear and the plurality of idler gears, at least one tooth surface of the meshing gears has a crowning shape. Note that the plurality of idler gears may be independently supported by any one of the methods described above (supported at at least one end portion in the rotation axis direction). That is, at least one of the plurality of idler gears may be rotatably supported by different members at both ends in the rotation axis direction. Further, at least one of the plurality of idler gears may be rotatably supported at one end in the rotation axis direction.

4 Photosensitive drum 8 Photosensitive unit 9 Developing unit 29 Developing frame body 32 Developing cover member 45 Bearing member 68 Idler gear 69 Developing roller gear 70 Spring 71 Clutch coupling 72 Release cam 73 Release lever 74 Development input coupling P Process cartridge

Claims (17)

A rotatable developer carrier;
A drive input unit to which a rotational driving force for rotating the developer carrier is input;
A plurality of gears that transmit the rotational driving force transmitted from the drive input unit to the developer carrier;
In a development unit having
The developing is characterized in that the tooth surface of at least one of the plurality of gears has a crowning shape in which the thickness of the central portion in the tooth width direction is larger than the thickness of the end portion in the tooth width direction. unit.   Among the plurality of gears, at least one tooth surface of the gears meshing with each other has a crowning shape such that the thickness of the central portion in the tooth width direction is larger than the thickness of the end portion in the tooth width direction. The developing unit according to claim 1.   The plurality of gears includes a developer carrier gear that is closest to the developer carrier in a gear train including the plurality of gears, and an idler gear that meshes with the developer carrier gear, and the developer carrier. 2. The gear and the idler gear according to claim 1, wherein at least one tooth surface has a crowning shape in which a thickness of a central portion in the tooth width direction is larger than a thickness of an end portion in the tooth width direction. Or the developing unit according to 2.   The developing unit according to claim 3, wherein the idler gear is a gear closest to the drive input unit in a gear train including the plurality of gears.   The tooth surface of the developer carrier gear has a crowning shape such that the thickness of the central portion in the tooth width direction is larger than the thickness of the end portion in the tooth width direction. The developing unit according to 1.   The developing unit according to claim 3, wherein both ends of the idler gear in the rotation axis direction are rotatably supported by different members.   The developing unit according to claim 3, wherein the idler gear is rotatably supported at one end portion in a rotation axis direction thereof.   A developer carrier support that rotatably supports the developer carrier, a first idler gear support that rotatably supports one end of the idler gear in the rotational axis direction, and the first idler gear support in the rotational axis direction of the idler gear. A second idler gear support portion that rotatably supports an end opposite to the 1 idler gear support portion, and the developer carrier gear is fixed to the developer carrier. The developing unit according to any one of claims 3 to 5.   The developing unit according to claim 8, wherein the developer carrier support part, the first idler gear support part, and the second idler gear support part are provided on different members.   The plurality of gears include a developer carrier gear that is closest to the developer carrier in a gear train including the plurality of gears, and a plurality of idler gears that transmit a rotational driving force to the developer carrier gear. Further, at least one tooth surface of the developer carrier gear and the plurality of idler gears that mesh with each other is such that the thickness of the central portion in the tooth width direction is larger than the thickness of the end portion in the tooth width direction. The developing unit according to claim 1, wherein the developing unit has a unique crowning shape.   The developing unit according to claim 10, wherein at least one of the plurality of idler gears is rotatably supported by separate members at both ends in the rotation axis direction.   The developing unit according to claim 10, wherein at least one of the plurality of idler gears is rotatably supported at one end portion in a rotation axis direction thereof. A connection release mechanism for switching the state of connection or release of drive transmission from the drive input unit to the plurality of gears;
A cover member that covers at least a part of a drive train from the drive input unit to the developer carrier and supports at least one of the plurality of gears;
Have
The connection release mechanism has an action member that projects to the outside of the cover member and receives the force for switching,
The developing unit according to claim 1, wherein the cover member has an opening through which the action member protrudes to the outside of the developing cover member.   The developing unit according to claim 13, wherein the action member performs the switching by receiving the force for switching in conjunction with a change in posture of the developing unit.   15. The developing according to claim 1, wherein the developing unit is detachable from an apparatus main body of an image forming apparatus having an image carrier on which an electrostatic image to be developed by the developing unit is formed. unit.   An electrophotographic photosensitive member and a developing unit according to any one of claims 1 to 15 for developing an electrostatic image formed on the electrophotographic photosensitive member. Removable process cartridge.   An image forming apparatus comprising: an image carrier; and a developing unit according to claim 1 that develops an electrostatic image formed on the image carrier.

Images