JP5021087B2 - Process cartridge - Google Patents

Description

  The present invention relates to a process cartridge that can be attached to and detached from an electrophotographic image forming apparatus main body.

  Here, the electrophotographic image forming apparatus forms an image on a recording medium using an electrophotographic image forming system. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (for example, a laser beam printer, an LED printer, etc.), a facsimile apparatus, a word processor, and the like.

  The process cartridge is a cartridge in which a charging unit, a developing unit or a cleaning unit and an electrophotographic photosensitive drum are integrally formed, and the cartridge can be attached to and detached from the main body of the electrophotographic image forming apparatus. In addition, at least one of the charging unit, the developing unit, and the cleaning unit and the electrophotographic photosensitive drum are integrally formed into a cartridge so that it can be attached to and detached from the main body of the electrophotographic image forming apparatus. Further, it means that at least the developing means and the electrophotographic photosensitive drum are integrated into a cartridge so that it can be attached to and detached from the electrophotographic image forming apparatus main body.

  Conventionally, in an electrophotographic image forming apparatus using an electrophotographic image forming process, an electrophotographic photosensitive drum and process means acting on the electrophotographic photosensitive drum are integrally formed into a cartridge. A process cartridge system is employed in which the cartridge can be attached to and detached from the main body of the electrophotographic image forming apparatus. According to this process cartridge system, the maintenance of the apparatus can be performed by the user himself / herself without depending on the service person, so that the operability can be remarkably improved. Therefore, this process cartridge system is widely used in electrophotographic image forming apparatuses.

  In an electrophotographic image forming apparatus, light corresponding to image information such as a laser, an LED, or a lamp is irradiated to an electrophotographic photosensitive drum (hereinafter referred to as a photosensitive drum). As a result, an electrostatic latent image is formed on the photosensitive drum. The electrostatic latent image is developed by a developing device. Further, the developed image formed on the photosensitive drum is transferred to a recording medium. Thereby, an image is formed on the recording medium.

  Patent Document 1 describes an inline-type color electrophotographic image forming apparatus in which a plurality of process cartridges are arranged in a line. Here, in the process cartridge 40, a drum unit 41 having a photosensitive drum 44 and a developing unit 42 having a developing roller 68 are rotatably coupled by a swing center 43. The photosensitive drum 44 is provided with a cartridge coupling 60 at the end of the photosensitive drum 44 in the axial direction. When the process cartridge 40 is mounted on the apparatus main body, the cartridge coupling 60 engages with the main body coupling 61 provided on the apparatus main body, and the driving force is transmitted. Further, a driving force is transmitted to the developing roller 68 via an idler gears 65 and 66 from an input gear 64 as a developing driving force transmitting member provided at the swing center 43 of the developing unit 42. Here, when the process cartridge 40 is mounted on the apparatus main body, the input gear 64 is engaged with a gear 67 provided on the apparatus main body and receives a driving force. That is, drive transmission from the apparatus main body to the photosensitive drum 44 and the developing roller 68 is performed independently.

Japanese Patent Laid-Open No. 2001-255806 (page 9-11, FIGS. 7-14)

  However, further downsizing of process cartridges and electrophotographic image forming apparatuses and improvement of image quality have been demanded in recent years. In the conventional example, the input gear is provided at the center of swinging in which the position does not change even when the developing unit swings. Therefore, the developing roller transmits the driving force from the input gear via the adder gear, and it is necessary to provide a space for this in the process cartridge. Further, the rotation accuracy of the developing roller is affected by the meshing of the input gear, idler gear, and main body gear.

  The present invention is a further development of the above-described prior art. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a process cartridge capable of improving the mounting property of the process cartridge and improving the rotation accuracy of the developing roller.

To achieve the above object, a typical configuration according to the present invention is a process cartridge having a photosensitive drum and a developing roller for developing an electrostatic latent image formed on the photosensitive drum, wherein the photosensitive drum In the process cartridge that is detachably mounted on the electrophotographic image forming apparatus main body in a state where the developing roller is in contact with the developing roller, the driven portion fixed to one end in the axial direction of the developing roller is engaged with the driven portion. An intermediate portion movable in a direction intersecting the axial direction of the developing roller with respect to the driven portion while maintaining, and intersecting an axial direction of the developing roller with respect to the intermediate portion while maintaining engagement with the intermediate portion A coupling member having a drive unit movable in a moving direction and capable of receiving a drive force for rotating the developing roller, and the drive unit A bearing member which rotatably holds, anda groove the bearing member is mounted, the bearing member, so that it can move the in a direction crossing the axial direction of the developing roller along the groove together with the drive unit It is provided in .

  According to the present invention, it is possible to improve the mountability of the process cartridge and improve the rotation accuracy of the developing roller.

1 is an overall configuration diagram of a color electrophotographic image forming apparatus according to an embodiment of the present invention in a first embodiment. FIG. 3 is a cross-sectional explanatory view of a process cartridge according to the first embodiment. It is an external appearance perspective view of the process cartridge in 1st Embodiment. FIG. 2 is a perspective view of a developing unit in the first embodiment. FIG. 6 is a schematic diagram illustrating an operation of mounting the process cartridge according to the first embodiment on the image forming apparatus main body. FIG. 2 is a perspective view of the process cartridge according to the first embodiment positioned on the image forming apparatus main body. It is a figure explaining the support structure of the developing roller in 1st Embodiment. It is decomposition | disassembly explanatory drawing of the shaft coupling member in 1st Embodiment. It is a section explanatory view of the shaft coupling member in a 1st embodiment. It is a perspective view of the shaft coupling member in the developing unit state in the first embodiment. 4 is a perspective view illustrating a first main body drive transmission member and a second main body drive transmission member of the image forming apparatus according to the first embodiment. FIG. It is a side view explaining operation | movement of the shaft coupling member before mounting of the process cartridge in 1st Embodiment. It is a schematic diagram explaining operation | movement of the shaft coupling member before mounting of the process cartridge in 1st Embodiment. It is a side view explaining operation | movement of the shaft coupling member after mounting of the process cartridge in 1st Embodiment. It is a schematic diagram explaining operation | movement of the shaft coupling member after mounting of the process cartridge in 1st Embodiment. It is a side view explaining positioning of a shaft coupling member in a 2nd embodiment. It is a perspective view explaining the shaft coupling member in a 3rd embodiment. It is a figure explaining operation | movement of the shaft coupling member in 3rd Embodiment. It is a figure explaining operation | movement of the shaft coupling member in a reference example . It is a figure explaining operation | movement of the shaft coupling member in a reference example . It is a figure explaining operation | movement of the shaft coupling member in a reference example .

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

[First Embodiment]
Embodiments of a process cartridge and an electrophotographic image forming apparatus according to the present invention will be described with reference to FIGS. FIG. 1 is an overall configuration diagram of a color electrophotographic image forming apparatus according to the present embodiment.

(Overall configuration of image forming apparatus)
First, an overall configuration of an electrophotographic image forming apparatus (hereinafter referred to as an image forming apparatus) 100 will be described with reference to FIG. As shown in FIG. 1, four detachable process cartridges 7 (7a, 7b, 7c, 7d) are mounted by mounting members (not shown). In FIG. 1, the process cartridge 7 is provided side by side with respect to the horizontal direction in the electrophotographic image forming apparatus main body 100A.

  Each process cartridge 7 includes an electrophotographic photosensitive drum (hereinafter referred to as a photosensitive drum) 1 (1a, 1b, 1c, 1d), a charging roller 2 (2a, 2b, 2c, 2d) around the photosensitive drum 1, Process means such as the developing roller 25 (25a, 25b, 25c, 25d) and the cleaning member 6 (6a, 6b, 6c, 6d) are integrally disposed. The charging roller 2 charges the surface of the photosensitive drum 1 uniformly, and the developing roller 25 develops the latent image formed on the photosensitive drum 1 with toner to make a visible image. The cleaning member 6 removes toner remaining on the photosensitive drum 1 after the developer image formed on the photosensitive drum 1 is transferred to a recording medium.

  A scanner unit 3 for selectively exposing the photosensitive drum 1 based on image information and forming a latent image on the photosensitive drum 1 is provided below the process cartridge 7.

  A cassette 17 containing a recording medium S is mounted at the lower part of the apparatus main body 100A. A recording medium conveying means is provided so that the recording medium S passes through the secondary transfer roller 70 and the fixing unit 74 and is conveyed above the apparatus main body 100A. That is, the feeding roller 54 that separates and feeds the recording medium S in the cassette 17 one by one, the transport roller pair 76 that transports the fed recording medium S, the latent image formed on the photosensitive drum 1 and the recording medium S. A registration roller pair 55 is provided for synchronizing with. Further, an intermediate transfer unit as an intermediate transfer unit for transferring a toner image formed on each photosensitive drum 1 (1a, 1b, 1c, 1d) above the process cartridge 7 (7a, 7b, 7c, 7d). 5 is provided. The intermediate transfer unit 5 has a driving roller 56, a driven roller 57, a primary transfer roller 58 (58a, 58b, 58c, 58d) at a position facing the photosensitive drum 1 of each color, and a position facing the secondary transfer roller 70. A transfer belt 9 is stretched over a roller 59. Then, the transfer belt 9 circulates and moves so as to face and come into contact with all the photosensitive drums 1, and is transferred from the photosensitive drum 1 by applying a voltage to the primary transfer rollers 58 (58a, 58b, 58c, 58d). Primary transfer is performed on the belt 9. Then, the toner on the transfer belt 9 is transferred to the recording medium S by applying a voltage to the opposing 59 roller and the secondary transfer roller 70 disposed in the transfer belt 9.

  In image formation, each photosensitive drum 1 is rotated, and the photosensitive drum 1 uniformly charged by the charging roller 2 is selectively exposed from the scanner unit 3. Thereby, an electrostatic latent image is formed on the photosensitive drum 1. The latent image is developed by the developing roller 25. As a result, each color developer image is formed on each photosensitive drum 1. In synchronization with this image formation, the registration roller pair 55 conveys the recording medium S to the secondary transfer position where the opposing roller 59 and the secondary transfer roller 70 are in contact with each other with the transfer belt 9 interposed therebetween. Then, each color developer image on the transfer belt is secondarily transferred to the recording medium S by applying a transfer bias voltage to the secondary transfer roller 70. As a result, a color image is formed on the recording medium S. The recording medium S on which the color image is formed is heated and pressurized by the fixing unit 74 to fix the developer image. Thereafter, the recording medium S is discharged to the discharge unit 75 by the discharge roller 72. The fixing unit 74 is disposed on the upper part of the apparatus main body 100A.

(Process cartridge)
Next, the process cartridge 7 embodying the present invention will be described with reference to FIGS. FIG. 2 is a main cross section of the process cartridge 7 containing a developer (hereinafter referred to as toner). The cartridge 7a containing yellow toner, the cartridge 7b containing magenta toner, the cartridge 7c containing cyan toner, and the cartridge 7d containing black toner have the same configuration.

  The process cartridge 7 (7a, 7b, 7c, 7d) includes a drum unit 26 (26a, 26b, 26c, 26d) as a first frame and a developing unit 4 (4a, 4b, 4c, 4d) as a second frame. And). The drum unit 26 includes a photosensitive drum 1 (1a, 1b, 1c, 1d), a charging roller 2 (2a, 2b, 2c, 2d), and a cleaning member 6 (6a, 6b, 6c, 6d). The developing unit 4 includes a developing roller 25.

  The photosensitive drum 1 is rotatably attached to the cleaning frame 27 of the drum unit 26 via a drum front bearing 10 and a drum back bearing 11 (see FIG. 3). A drum coupling 16 and a flange 85 are provided at the end of the photosensitive drum 1.

  As described above, the charging roller 2 and the cleaning member 6 are disposed on the circumference of the photosensitive drum 1. Further, the residual toner removed from the surface of the photosensitive drum 1 by the cleaning member 6 falls into the removed toner chamber 27a. Then, the photosensitive drum 1 is rotationally driven in accordance with the image forming operation by transmitting a driving rotational force of a main body driving motor (not shown) as a driving source to the drum unit 26. The charging roller 2 is rotatably attached to the cleaning frame body 27 via the charging roller bearing 28, and is pressurized toward the photosensitive drum 1 by the charging roller pressing member 46, and is rotated following the photosensitive drum 1.

  The developing unit 4 includes a developing roller 25 that contacts the photosensitive drum 1 and rotates in the direction of arrow B, and a developing frame 31 that supports the developing roller 25. The developing roller 25 is rotatably supported by the developing frame 31 via a pre-development bearing 12 and a developing rear bearing 13 that are respectively attached to both sides of the developing frame 31 (see FIG. 4). A toner supply roller 34 that rotates in the direction of arrow C in contact with the developing roller 25 and a developing blade 35 for regulating the toner layer on the developing roller 25 are disposed on the circumference of the developing roller 25. Further, the toner accommodating portion 31 a of the developing frame 31 is provided with a toner conveying member 36 for agitating the accommodated toner and conveying the toner to the toner supply roller 34.

  FIG. 3 is an external perspective view of the process cartridge 7. The developing unit 4 is rotatably attached to the drum unit 26. In the developing unit 4, the front support pin 14 and the back support pin 15 that are press-fitted into the cleaning frame body 27 are engaged with the suspension holes 12 a and 13 a of the pre-development bearing 12 and the development back bearing 13. As a result, the developing unit 4 is supported by the cleaning frame 27 so as to be rotatable about the support pins 14 and 15 (see FIG. 2). The cleaning frame 27 is provided with a drum front bearing 10 and a drum back bearing 11 that rotatably support the photosensitive drum 1. The drum back bearing 11 supports a drum coupling 16 coupled to the photosensitive drum 1. The drum front bearing 10 supports a flange 85. Here, the drum coupling 16 is a drum coupling member for transmitting a driving rotational force (first driving rotational force) from the apparatus main body 100 </ b> A to the photosensitive drum 1.

  Further, the developing unit 4 shown in FIG. 4 is attached to the drum unit 26 by the pressure spring 38 provided on the developing frame 31 and the tension spring 39 provided on the pre-development bearing 12 when the process cartridge 7 forms an image. It is the composition which is energized. By these pressure spring 38 and tension spring 39, the holes 12 a and 13 a of the pre-development bearing 12 and the development back bearing 13 become the center of rotation, and a pressure is applied for the development roller 25 to contact the photosensitive drum 1.

  In the contact development method in which development is performed by contacting the photosensitive drum 1 and the developing roller 25, the photosensitive drum 1 is preferably a rigid body, and the developing roller 25 is preferably a roller having an elastic body. As this elastic body, a solid rubber single layer or a solid rubber layer coated with a resin coating in consideration of charge imparting property to toner is used.

  Next, a series of operations relating to image formation of the process cartridge 7 will be described (see FIGS. 1 and 2). When the image information is sent to the image forming apparatus 100, a main body drive motor (not shown) starts rotating, and the driving rotational force is transmitted to the photosensitive drum 1, the developing roller 25, the toner supply roller 34, and the toner conveying member 36. . A charging bias voltage is applied to the charging roller 2 from the apparatus main body 100A to uniformly charge the surface of the photosensitive drum 1. Then, according to the image information, exposure is performed from the scanner unit 3 and a latent image is formed on the photosensitive drum 1.

  The toner in the toner container 31 a is sent to the toner supply roller 34 by the rotation of the toner transport member 36. Then, the toner supply roller 34 rotates to supply toner to the outer periphery of the rotating developing roller 25. The supplied toner is frictionally charged on the outer periphery of the developing roller 25 by the developing blade 35. A developing bias voltage is applied to the developing roller 25 from a power supply unit (not shown) provided in the image forming apparatus 100. As a result, the electrostatic latent image formed on the electrophotographic photosensitive drum 1 is developed. The developing roller 25 is disposed so as to face the photosensitive drum 1. The developing roller 25 is configured to contact the photosensitive drum 1 and develop the electrostatic latent image formed on the photosensitive drum 1.

(Mechanism for mounting the process cartridge to the image forming apparatus main body)
Next, a mounting mechanism for mounting the process cartridge 7 embodying the present invention into the apparatus main body 100A will be described with reference to FIG.

  FIG. 5A is a diagram illustrating a state before the process cartridge 7 is mounted in the apparatus main body 100A. In FIG. 5A, the process cartridge 7 is mounted in the direction of arrow E from an opening 82a provided in the front plate 82 of the apparatus main body 100A. At that time, the guide portion 27b provided integrally with the cleaning frame 27 of the process cartridge 7 is mounted while being guided while being placed on the main body guide member 81 provided on the apparatus main body 100A. The main body guide member 81 is a mounting member for detachably mounting the process cartridge 7.

  FIG. 5B is a diagram illustrating a state in which the process cartridge 7 is in the process of being completely attached to the apparatus main body 100A. The guide member 81 provided in the apparatus main body 100A is provided with an inclined portion 81a inclined upward on the downstream side in the mounting direction. Further, the cleaning frame 27 is provided with an inclined portion 27c inclined downward at the upstream end portion in the mounting direction. When the process cartridge 7 is mounted on the apparatus main body 100A, the guide portion 27b of the cleaning frame 27 rides on the inclined portion 81a, and the inclined portion 27c rides on the main body guide portion 81. As a result, the process cartridge 7 moves in a direction approaching the intermediate transfer unit 5 (upward).

  FIG. 5C is a diagram illustrating a state where the process cartridge is mounted on the apparatus main body 100A. When the mounting of the process cartridge 7 is further continued in a state where the process cartridge 7 has moved in the direction approaching the intermediate transfer unit 5, the abutting portion 27d provided integrally with the cleaning frame 27 is provided with the rear plate 83 of the apparatus main body 100A. Abut. Thereby, the mounting of the process cartridge 7 to the image forming apparatus 100 is completed.

  In this state, the pressed portion 11 a of the drum back bearing 11 comes into contact with the back pressing member 91 provided on the back side plate 83 and is pushed upward by the pressure spring 92. Then, the cartridge positioning portion 11b provided at the upper portion of the drum back bearing 11 abuts against the abutting portion 83a which is the main body positioning portion of the back side plate 83, and the position of the process cartridge 7 with respect to the apparatus main body 100A on the back side is determined.

  Further, the pulled portion 10 a of the drum front bearing 10 is engaged with a pulling member 93 provided on the front side plate 82. The tension member 93 is lifted upward by the tension spring 94 provided on the front side plate 82, and the pulled portion 10 a is also lifted upward. Then, the abutting portion 10b which is a cartridge positioning portion of the drum front bearing 10 contacts the positioning portion 82b which is the main body positioning portion of the main body front side plate 82 and is positioned with respect to the apparatus main body 100A on the front side of the process cartridge 7. .

  Further, as shown in FIG. 6, the abutting portion 83 a is substantially V-shaped and is configured to abut on the positioning surface 11 b of the drum back bearing 11. The drum front bearing 10 is configured such that a pulling member 93 provided on the front side plate 82 engages with a pulled portion 10a of the drum front bearing 10 and is pulled in the direction of arrow P. As for the positioning, the drum rear bearing 11 is in contact with a substantially V-shaped drum positioning portion 82 b provided on the front plate 82. Then, the pressure applied to the drum front bearing 10 and the drum back bearing 11 from the apparatus main body 100A is applied in the directions of arrows P and R. Therefore, it is possible to accurately position the drum front bearing 10 and the drum back bearing 11 that rotatably support the photosensitive drum 1 that positions the process cartridge 7 with respect to the apparatus main body 100A. Further, the cleaning frame 27 is provided with a boss 27g for preventing rotation of the process cartridge 7 on the side surface, and the boss 27g is fitted to a rotation stopper receiving member 51 provided on the apparatus main body 100A. Then, the process cartridge 7 is prevented from rotating in the apparatus main body 100A.

  In FIG. 6, the drive side engaging portion 23 is omitted for easy understanding of the above description.

(Configuration of developing roller support and developing driving force input section in process cartridge)
Next, the structure of the developing driving force input unit and the supporting structure of the developing roller 25 in the process cartridge 7 embodying the present invention will be described with reference to FIGS. FIG. 7 is a view showing one end side (back side) in the longitudinal direction of the support portion of the developing roller 25. In FIG. 7, the developing roller shaft 25 j of the developing roller 25 is rotatably fitted to the inner periphery of the developing back bearing 13. A regulating roller 47 for regulating the contact amount of the developing roller 25 to the photosensitive drum 1 is rotatably fitted to the developing roller shaft 25j between the rubber roller portion 25g of the developing roller 25 and the developing back bearing 13. Is provided. Here, the support structure on one end side in the longitudinal direction of the developing roller 25 has been described. Similarly, the bearing portion is integrally provided on the bearing member on the other end side in the longitudinal direction, and the other end side of the developing roller shaft 25j can be rotated. Is fitted.

  In this embodiment, the Oldham coupling 20 which is a shaft coupling member is used for the developing driving force input portion. The configuration of the Oldham coupling 20 will be described with reference to FIGS. Here, in order to explain the configuration of the Oldham coupling 20, the developing rear bearing 13 is not shown.

  In FIG. 8, Oldham coupling (coupling member) 20 includes a driven side engaging portion (driven portion) 21, an intermediate engaging portion (intermediate portion) 22, and a driving side engaging portion (driving portion) 23. Yes.

  Here, the driven side engaging portion 21 is fixedly attached to the end portion of the developing roller shaft 25j. As a fixing method, a coupling method using a spring pin or a parallel pin, or as shown in FIG. 8, a cut portion 25c is provided on the end surface of the developing roller shaft 25j, and a hole on the driven side engaging portion 21 side is the same. There is a method of fitting in a shape. The shaft portion 23 b of the driving side engaging portion 23 is rotatably held in the hole 19 a of the engaging portion bearing member (holding portion) 19. The drive side engaging portion 23 is integrally formed with protrusions 23c1 to 23c4 that engage with a main body developing coupling 53 (see FIG. 11) that is a second main body drive transmission member of the apparatus main body 100A described later. . The Oldham coupling 20 transmits a driving rotational force (second driving rotational force) from the apparatus main body 100 </ b> A to the developing roller 25 while allowing a deviation between the axial line of the main body developing coupling 53 and the axial line of the developing roller 25. .

  In FIG. 9, the configuration of the Oldham coupling 20 will be described in more detail with reference to cross-sectional views. 9A is a cross-sectional view taken perpendicular to the direction of arrow H in FIG. 8, and FIG. 9B is a cross-sectional view taken perpendicular to the direction of arrow I in FIG.

  In FIG. 9A, the driven side engaging portion 21 is integrally provided with a rib 21a. The intermediate engagement portion 22 is provided with a groove 22a, and the rib 21a and the groove 22a are fitted so as to be movable in the direction of arrow H in FIG.

  In FIG. 9B, the drive side engaging portion 23 is integrally provided with a rib 23a. The intermediate engagement portion 22 is provided with a groove 22b, and the rib 23a and the groove 22b are fitted so as to be movable in the direction of arrow I in FIG.

  FIG. 10 is a view showing the configuration of the coupling provided in the process cartridge 7. Protrusions 23 c 1 to 23 c 3 projecting in the axial direction are formed on the end face of the driving side engaging portion 23 of the Oldham coupling 20 provided in the developing unit 4. A centering boss 23c4 for aligning the axis (rotation center) with the main body development coupling 53 protrudes from the end face of the drive side engaging portion 23 in the axial direction. A triangular drum coupling 16 is provided on one end side in the axial direction of the photosensitive drum 1. The guide portion 19b of the engaging portion bearing member 19 is guided by a groove 48a of the side cover 48 fixed to the developing unit 4 with screws (not shown) so as to be movable in a direction intersecting the axial direction of the developing roller 25. . That is, the driving side engaging portion 23 is movable in the intersecting direction with respect to the developing unit 4.

  FIG. 11 is a diagram illustrating a configuration of a coupling provided in the apparatus main body 100A. In FIG. 11, a drum drive coupling 66 which is a first main body drive transmission member for transmitting the drive of the apparatus main body 100A to the photosensitive drum 1 is provided with a hole 66a having a substantially triangular cross section. Also, holes 53a to 53c are provided in the main body developing coupling 53 which is a second main body driving transmission member for transmitting the driving rotational force (second driving rotational force) from the apparatus main body 100A to the developing roller 25. Yes. The drum drive coupling 66 is urged toward the process cartridge 7 by a pressing member 77 such as a compression spring. The drum drive coupling 66 is movable in the axial direction of the photosensitive drum 1. Further, when the drum cartridge 16 and the hole 66a of the drum drive coupling 66 are in contact with each other when the process cartridge 7 is mounted on the apparatus main body 100A, the drum drive coupling 66 is pushed by the drum coupling 16. fall back. Then, when the drum driving coupling 66 rotates, the drum coupling 16 and the hole 66a are engaged with each other, and the driving rotational force is transmitted to the photosensitive drum 1.

  The main body development coupling 53 is urged in a direction toward the process cartridge 7 by a pressing member 73 such as a compression spring toward a direction parallel to the axial direction of the photosensitive drum 1. However, the main body developing coupling 53 is provided in the apparatus main body 100A without any play in the direction intersecting the axial direction. That is, the main body development coupling 53 is movable only in the axial direction except that it rotates for driving transmission.

  When the process cartridge 7 enters the apparatus main body 100A and the drive side engaging portion 23 and the main body developing coupling 53 engage with each other, the projections 23c1 to 23c3 and the holes 53a to 53c may not be in phase. In this case, the tips of the protrusions 23c1 to 23c3 come into contact with places other than the holes 53a to 53c, and the main body development coupling 53 moves backward in the axial direction against the urging force of the pressing member 73. However, when the main body development coupling 53 rotates and the projections 23c1 to 23c3 and the holes 53a to 53c are in phase, the main body development coupling 53 advances by the urging force of the pressing member 73. Then, the projections 23c1 to 23c3 and the holes 53a to 53c are engaged, and the centering boss 23c4 that is the engaging portion positioning portion and the centering hole 53e that is the transmission member positioning portion are also fitted, The axis (rotation center) of the main body development coupling 53 coincides. When the main body developing coupling 53 rotates, the projections 23c1 to 23c3 and the holes 53a to 53c are engaged with each other, and a driving rotational force (second driving rotational force) is transmitted to the developing roller 25.

  Here, drive transmission to the drum drive coupling 66 and the main body development coupling 53 is performed by a motor provided in the apparatus main body 100A. There are a configuration in which one motor is used for each color process cartridge, and a configuration in which the drive is transmitted to several color process cartridges by one motor.

(Operation of Oldham coupling in process cartridge)
Next, the operation of Oldham coupling in the process cartridge 7 will be described with reference to FIGS.

  FIG. 12 is a side view showing a state before the process cartridge 7 is mounted on the main body of the image forming apparatus 100, and FIG. 13 is a cross-sectional view in the longitudinal direction.

As described above, before the process cartridge 7 is mounted on the apparatus main body 100A, the developing roller 25 and the photosensitive drum 1 are in contact with each other as shown in FIG. The arm portion 18 a of the biasing member (biasing portion) 18 that is a torsion coil spring provided in the side cover 48 abuts on the locking portion 19 c of the engaging portion bearing member 19. As a result, the driving side engaging portion 23 is urged in a direction intersecting the axial direction of the developing roller 25 (in the direction of arrow Q in FIG. 13). Therefore, the contact portion 19d of the engagement portion bearing member 19 contacts the contact portion (butting portion) 11c provided in the drum back bearing 11, and the position of the engagement portion bearing member 19 is determined. That is, the driving side engaging portion 23 is positioned at a certain position. Here, the contact portion 11c of the drum back bearing 11 is formed of two surfaces parallel to the axis of the V-shaped photosensitive drum 1. The engaging portion bearing member 19 can be held in parallel with the axis 1c of the photosensitive drum 1 by contacting the engaging portion bearing member 19 with the abutting portion 11c. The drum back bearing 11 is integrally provided with a positioning portion 11b. Therefore, the driving side engaging portion 23 rotatably supported by the engaging portion bearing member 19 is accurately positioned with respect to the rear plate 83 of the apparatus main body 100A where the positioning portion 11b is positioned. Therefore, the positioning can be performed with respect to the axis 53d of the main body development coupling 53 provided in the apparatus main body 100A with high accuracy. Here, the driving side engaging portion 23 of the Oldham coupling 20 is rotatably fitted to the engaging portion bearing member 19. Therefore, in this state, the axis line 23c5 of the driving side engaging portion 23 of the Oldham coupling 20 is very close to the axis line 25k of the developing roller 25 by a distance d3. That is, the position where the driving side engaging portion 23 is positioned is a position where the process cartridge 7 can enter the apparatus main body 100A and can be smoothly engaged with the main body developing coupling 53. Here, the biasing member 18 is used as a biasing force for the engaging portion bearing member 19. However, the engaging portion bearing member 19 may be brought into contact with the contact portion 11c by providing the engaging portion bearing member 19 with an elastic portion that can be elastically deformed integrally.

  This will be described in more detail with reference to FIG. When the driving side engaging portion 23 is engaged with the main body developing coupling 53 and rotated, the driving side engaging portion 23 is positioned by the main body developing coupling 53 as described later. Therefore, the contact portion 19b of the engagement portion bearing member 19 is separated from the drum back bearing 11, that is, the contact portion 11c. Therefore, when the process cartridge 7 enters the apparatus main body 100A, the axis 23c5 of the drive side engaging portion 23 is shifted from the axis 53d of the main body developing coupling 53 by a certain distance d3 toward the photosensitive drum 1 side. Engagement will begin. When the process cartridge 7 further enters from this state, the chamfered portion 23c6 (FIG. 10) provided in the centering boss 23c4 and the chamfered portion 53f (FIG. 11) provided in the hole 53e come into contact with each other. It is configured to engage while correcting misalignment. At this time, the driving side engaging portion 23 is accurately positioned with respect to the apparatus main body 100A by the contact portion 11c. Therefore, the positioning is accurately performed with respect to the main body developing coupling 53 provided in the apparatus main body 100A. Therefore, it is not necessary to make the chamfered portion 23c6 and the chamfered portion 53f extremely large, and the drive side engaging portion 23 and the main body developing coupling 53 can be reduced. Then, as shown in FIG. 15, when the main body developing coupling 53 rotates and the phases of the projections 23c1 to 23c3 of the driving side engaging portion 23 and the holes 53a to 53c of the main body developing coupling 53 match, The hole 53e is fitted. As a result, the rotation center 23 c of the drive side engaging portion 23 and the rotation center 53 d of the main body developing coupling 53 coincide.

  FIG. 14 is a view showing a state in which the process cartridge is mounted on the apparatus main body 100A, and FIG. 15 is a longitudinal sectional view. In the apparatus main body 100A (not shown), the driving side engaging portion 23 of the Oldham coupling 23 in the process cartridge 7 and the main body developing coupling 53 of the apparatus main body 100A are engaged. That is, the driving side engaging portion 23 of the Oldham coupling 20 is positioned in the main body developing coupling 53 by fitting the boss 23c4 and the hole 53e. As shown in FIG. 15, the driving side engaging portion 23 and the main body developing coupling 53 are engaged with each other with the engaging portion bearing member 19 having a gap 80 with respect to the drum back bearing 11. The axis 25k of the developing roller, the axis 23c5 of the driving side engaging portion 23, and the axis 53d of the main body developing coupling 53 are substantially coincident with each other. The distance from each drum axis 1c is also d4.

  As described above, in the present embodiment, the driving rotational force is directly applied to the developing roller 25 from the main body developing coupling 53 that rotates independently of the drum driving coupling 66 that inputs the driving rotational force to the photosensitive drum 1 via the coupling 22. It is configured to input. Therefore, the rotational accuracy of the photosensitive drum 1 can be suppressed from being affected by the rotation of the developing roller 25, and further, the rotational accuracy of the developing roller 25 itself can be improved and the image quality can be improved.

  Further, the driving side engaging portion 23 of the Oldham coupling 20 is positioned with respect to the cartridge 7 so as to be movable in a direction intersecting the axis 25k of the developing roller 25. Accordingly, the main body developing coupling 53 and the driving side engaging portion 23 can be engaged in a space-saving manner without using a large guide guide or the like. Therefore, the process cartridge 7 and the image forming apparatus 100 can be reduced in size. In addition, the mountability of the process cartridge 7 to the apparatus main body 100A is improved.

[Second Embodiment]
In the first embodiment, the configuration in which the engaging portion bearing member 19 is biased to the drum back bearing 10 that supports the photosensitive drum 1 has been described. However, as shown in FIG. 16, the engaging portion bearing member 19 on the cleaning frame 27 may be provided with a contact portion 27f capable of contacting.

  FIG. 16 is a view showing a state before the process cartridge 7 is mounted on the apparatus main body 100A. As described in the first embodiment, the arm portion 18 a of the biasing member 18 that is a torsion coil spring provided in the side cover 48 abuts on the locking portion 19 c of the engaging portion bearing member 19. Accordingly, the driving side engaging portion 23 is urged in a direction intersecting with the axial direction of the developing roller 25. Therefore, the contact portion 19d of the engagement portion bearing member 19 contacts the contact portion 27f provided on the cleaning frame 27, and the position of the engagement portion bearing member 19 is determined. Here, the contact portion 27 f of the cleaning frame 27 is formed by two surfaces parallel to the axis of the V-shaped photosensitive drum 1. The cleaning frame 27 is provided with a drum back bearing 11, and the drum back bearing 11 is integrally provided with a positioning portion 11 b. Therefore, the driving side engaging portion 23 supported rotatably by the engaging portion bearing member 19 can also be accurately positioned with respect to the rotation center of the photosensitive drum 1 and the apparatus main body 100A. Therefore, it is possible to accurately position with respect to the axis 53d of the main body development coupling 53 provided in the apparatus main body 100A.

  Other configurations are the same as those of the first embodiment, and the same effects as those of the first embodiment can be obtained.

[Third Embodiment]
In the first embodiment, the Oldham coupling is used as the shaft coupling member. However, in a process cartridge having a small developing roller diameter, a spring as an elastic portion is provided on the intermediate engagement portion 22 of the shaft coupling member 20 as shown in FIG. The configuration used may be used.

  In FIG. 17, the shaft coupling member 20 includes a driven side engaging portion 21, an intermediate engaging portion 22, and a driving side engaging portion 23. The intermediate engaging portion is constituted by a spring 22. The driven side engaging portion 21 is provided with a boss 21a for engaging the spring 22. Similarly, the drive side engaging portion 23 is also provided with a boss 23 a that engages with the spring 22. The spring 22 is provided with an arm portion 22a that engages with the driven side engaging portion boss 21a and an arm portion 22b that engages with the driving side engaging portion boss 23a. The shaft portion 23 b of the drive side engaging portion 23 is rotatably engaged with the hole 19 a of the engaging portion bearing member 19. The drive-side engagement portion 23 is integrally formed with protrusions 23c1 to 23c4 that engage with the main body development coupling 53 that is the second main body drive transmission member of the apparatus main body 100A. Similarly to the first embodiment, when the driving of the apparatus main body 100A is transmitted to the driving side engaging portion 23, the driving is transmitted from the boss 23a of the driving side engaging portion 23 to the arm portion 22b of the spring 22. The driving rotational force transmitted to the spring 22 is configured to be transmitted from the arm portion 22a of the spring 22 to the boss 21a of the driven side engaging portion 21.

  In the present embodiment, the spring 22 is used as the intermediate engaging portion. However, as shown in FIG. 18, a cylindrical elastic rubber 22 that is an elastic portion may be used. The elastic rubber 22 is provided with a rib 22a that engages with the boss 23a of the driving side engaging portion 23 and the boss 21a of the driven side engaging portion 21 to transmit driving.

  Other configurations are the same as those of the first embodiment, and the same effects as those of the first embodiment can be obtained.

[ Reference example ]
Next, the example which hold | maintains the drive side engaging part 23 with a drum bearing is demonstrated as a reference example. In the first embodiment, the configuration in which the engaging portion bearing member 19 is biased to the drum back bearing 10 that supports the photosensitive drum 1 by the biasing spring 18 has been described. In this reference example , as shown in FIG. 19, the drum back bearing 11 is provided with a hole 11 f that is a holding portion for holding the driving side engaging portion 23. The inner diameter of the hole 11 f is larger than the outer diameter of the driving side engaging portion 23. That is, the driving side engaging portion 23 is held so as to be movable in the direction intersecting the axis of the developing roller 25 with respect to the hole 11f. In the first embodiment, as shown in FIG. 13, the drive side engaging portion 23 is positioned with respect to the axis 53 d of the main body developing coupling 53 in the direction positioned on the drum back bearing 11 via the engaging portion bearing member 19. The position was shifted. Therefore, in this reference example , the configuration is such that the axis line 23c5 of the drive side engaging portion 23 may be displaced in any direction as long as it intersects the axis line of the developing roller 25. Therefore, the driving side engaging portion 23 can smoothly engage with the main body developing coupling 53 when the process cartridge 7 enters the apparatus main body 100A. FIG. 20 shows a state in which the driving side engaging portion 23 is positioned by the main body developing coupling (not shown). That is, the driving side engaging portion 23 is positioned by the main body developing coupling (not shown), and thus is not in contact with the hole 11f.

  Further, as shown in FIG. 21, a hole 27 f that holds the drive side engaging portion 23 may be provided in the cleaning frame body 27.

  Other configurations are the same as those of the first embodiment, and the same effects as those of the first embodiment can be obtained.

[Other Embodiments]
In the embodiment described above, four process cartridges are used. However, the number used is not limited, and may be set as needed.

  In the above-described embodiment, the printer is exemplified as the image forming apparatus, but the present invention is not limited to this. For example, the image forming apparatus may be another image forming apparatus such as a copying machine or a facsimile machine, or another image forming apparatus such as a multi-function machine combining these functions. In the above-described embodiments, an intermediate transfer member is used, toner images of each color are sequentially transferred onto the intermediate transfer member, and the toner images carried on the intermediate transfer member are collectively transferred onto a transfer material. Although the forming apparatus is illustrated, the present invention is not limited to this. For example, an image forming apparatus that uses a recording medium carrier and sequentially superimposes and transfers the toner images of the respective colors onto the recording medium carried on the recording medium carrier. The same effect can be obtained by applying the present invention to these image forming apparatuses.

S: Recording medium 1 (1a-1d) ... Photosensitive drum 2 (2a-2d) ... Charging roller 2j ... Shaft 3 ... Scanner unit 4 (4a-4d) ... Developing unit (second frame)
DESCRIPTION OF SYMBOLS 5 ... Electrostatic intermediate transfer unit 6 (6a-6d) ... Cleaning member 7 (7a-7d) ... Process cartridge 10 ... Drum front bearing 11 ... Drum back bearing 12 ... Pre-development bearing 13 ... Development back bearing 14 ... Front shaft member DESCRIPTION OF SYMBOLS 15 ... Back shaft member 16 ... Drum coupling 17 ... Cassette 18 ... Biasing spring 19 ... Biasing member 20 ... Oldham coupling (shaft coupling member)
DESCRIPTION OF SYMBOLS 21 ... Drive side engaging part 22 ... Intermediate | middle engaging part 23 ... Drive side engaging part 25 (25a-25d) ... Developing roller 25c ... Cut part 25g ... Rubber roller part 25j ... Developing roller axis 25k ... Developing roller axis line 26 (26a) 26d) ... drum unit 27 ... cleaning frame 27a ... removal toner chamber 28 ... charging roller bearing 30 ... toner container 31 ... development frame 34 ... toner supply roller 35 ... development blade 36 ... toner conveying member 38 ... pressure spring 39 ... Tension spring 46 ... Charging roller pressure member 47 ... Regulation roller 48 ... Side cover 53 ... Main body development coupling 53a to 53c ... Hole 53d ... Axis 66 ... Drum drive coupling 66a ... Hole 70 ... Secondary transfer roller 71 ... Intermediate transfer Body cleaning unit 85 ... flange 86 ... drum unit 100 ... electrophotographic image Forming apparatus

Claims (4)

A process cartridge having a photosensitive drum and a developing roller for developing an electrostatic latent image formed on the photosensitive drum, the cartridge being removed from the electrophotographic image forming apparatus main body in a state where the photosensitive drum and the developing roller are in contact with each other. In the process cartridge that can be mounted,
A driven portion fixed to one end side in the axial direction of the developing roller, and an intermediate portion movable in a direction intersecting the axial direction of the developing roller with respect to the driven portion while maintaining engagement with the driven portion; A driving unit that can move in a direction intersecting the axial direction of the developing roller with respect to the intermediate part while maintaining engagement with the intermediate part, and can receive a driving force for rotating the developing roller. A coupling member having a drive unit;
A bearing member that rotatably holds the drive unit, and a groove part to which the bearing member is attached , and the bearing member intersects the axial direction of the developing roller along the groove part together with the drive unit. A process cartridge is provided so as to be movable . An urging portion for urging the bearing member in a direction intersecting the axial direction of the developing roller; and an abutting portion against which the bearing member urged by the urging portion abuts, and the abutting portion 2. The process cartridge according to claim 1 , wherein when the bearing member abuts, the process cartridge is disposed at a position where an axis of the drive unit is shifted from an axis of the developing roller. The process cartridge according to claim 2, wherein the urging portion is an elastic body. The process cartridge according to any one of claims 1 to 3, wherein the coupling member is Oldham coupling.

Images