JP4458318B2 - Photosensitive drum device, process cartridge, and electrophotographic image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photosensitive drum device that is driven to rotate, a process cartridge including the photosensitive drum device, and an electrophotographic image forming apparatus.
[0002]
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.
[0003]
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 that 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.
[0004]
[Prior art]
An electrophotographic image forming apparatus such as a copying machine or a printer forms an electrostatic latent image on the peripheral surface of a photosensitive drum, and develops the latent image and transfers it to a recording sheet to form an image. The photosensitive drum includes a cylinder having a photosensitive layer, a flange member fitted to both ends of the cylinder, and a rotating shaft that integrally rotates these members. Pins whose both ends protrude in the radial direction of rotation are fitted to the rotary shaft, and the flange member is provided with fitting grooves for fitting with the pins. In general, the rotary shaft and the flange member are coupled by fitting the pin and the fitting groove. When the rotary shaft and the flange member are coupled in this way, when the fitting groove is large with respect to the pin, a backlash occurs between the pin and the fitting groove, and the backlash rotates when the drive is transmitted from the rotary shaft to the flange member. There is a risk of unevenness. Therefore, conventionally, rotation unevenness has been reduced by setting the fitting groove small with respect to the pin and eliminating the play by press-fitting the pin.
[0005]
[Problems to be solved by the invention]
However, in the conventional photoconductive drum device and the image forming apparatus having the photoconductive drum, for example, when the pin protruding from the rotation shaft is a spring pin, the thickness varies, so the spring pin is used as a fitting groove. There is a possibility that a high pressure input is required at the time of press-fitting. Similarly, since the drive cannot be transmitted at a fixed contact position with respect to the fitting groove due to variations in pin thickness, there is a possibility that stable rotation cannot be obtained.
[0006]
Therefore, the present invention reduces the rotation unevenness of the photosensitive drum when driving is transmitted by eliminating play in the fitting between the rotating shaft and the flange member, and the pin engaged with the rotating shaft is easily attached to the flange member. It is an object of the present invention to provide a photosensitive drum device that can be fitted to the photosensitive drum and that can stably rotate, a process cartridge including the photosensitive drum device, and an electrophotographic image forming apparatus.
[0007]
[Means for Solving the Problems]
  The first invention according to the present application is:In a photosensitive drum device used in an electrophotographic image forming apparatus,
(I) saidElectrophotographic image forming apparatusEquipmentDriving from the main unitPowerA rotating shaft that is rotationally driven by
(Ii)A cylinder having a photosensitive layer on the surface;
(Iii)The rotation axisA pin provided through a through hole provided in the pin, wherein one end and the other end of the pin are connected to the rotating shaft.In the radial directionFrom the rotating shaftProtrusionis doingidea,
(Iv)The outer circumference of the cylinderoneMates to endAndInner circumference fits with the rotating shaft passing through the center of the cylinderWhen the rotating shaft receives the driving force from the apparatus main body, the rotating shaftRotate togetherLikeA flange member having a fitting groove for fitting with the pin,
  The fitting groove is point-symmetric with respect to the rotation center of the rotation shaft;
  Of the fitting grooveThe fitting groove is arranged such that a center line of a width on one side in the longitudinal direction is arranged at a position deviated by a distance X from the axial center of the pin in a direction opposite to the rotation direction of the cylinder by the driving force. The center line of the width on the other side in the longitudinal direction of the pin is arranged at a position that is eccentric from the axis of the pin in the direction opposite to the rotation direction of the cylinder by a distance X,
  One side protrusion provided on the side wall provided on the one side in the longitudinal direction of the fitting groove and on the upstream side in the rotation direction of the flange member, and the side wall provided with the one side protrusion A one-side protrusion that abuts the pin against the opposite side wall surface;
  The other side projection provided on the side wall surface provided on the other side in the longitudinal direction of the fitting groove and on the upstream side in the rotation direction of the flange member, and the side wall surface provided with the other side projection. The other side projection that abuts the pin against the opposite side wall surface,
HaveA flange member;
A photosensitive drum device.
[0008]
A second invention according to the present application is the photosensitive drum device according to the first invention, wherein the pin is a spring pin or a parallel pin.
[0009]
  Furthermore, a third invention according to the present application is an electrophotographic image forming apparatus.EquipmentOn the bodyRemovably mountedIn the process cartridge,
(A)(I) the deviceDriving from the main unitPowerA rotating shaft that is rotationally driven by
(Ii)A cylinder having a photosensitive layer on the surface;
(Iii)The rotation axisA pin provided through a through hole provided in the pin, wherein one end and the other end of the pin are connected to the rotating shaft.In the radial directionFrom the rotating shaftProtrusionis doingidea,
(Iv) The outer periphery of the cylinderoneMates to endAndThe inner circumference fits with the rotating shaft that passes through the center of the cylinder.When the rotation shaft receives the driving force from the apparatus main body, the rotation shaftRotate togetherLikeA flange member having a fitting groove for fitting with the pin,
  The fitting groove is point-symmetric with respect to the rotation center of the rotation shaft;
  Of the fitting grooveThe fitting groove is arranged such that a center line of a width on one side in the longitudinal direction is arranged at a position deviated by a distance X from the axial center of the pin in a direction opposite to the rotation direction of the cylinder by the driving force. The center line of the width on the other side in the longitudinal direction of the pin is arranged at a position that is eccentric from the axis of the pin in the direction opposite to the rotation direction of the cylinder by a distance X,
  One side protrusion provided on the side wall provided on the one side in the longitudinal direction of the fitting groove and on the upstream side in the rotation direction of the flange member, and the side wall provided with the one side protrusion A one-side protrusion that abuts the pin against the opposite side wall surface;
  The other side projection provided on the side wall surface provided on the other side in the longitudinal direction of the fitting groove and on the upstream side in the rotation direction of the flange member, and the side wall surface provided with the other side projection. The other side projection that abuts the pin against the opposite side wall surface,
HaveA flange member;
An electrophotographic photosensitive drum having
(B) process means acting on the electrophotographic photosensitive drum;
It is a process cartridge characterized by having.
[0010]
A fourth invention according to the present application is the process cartridge according to the third invention, wherein the pin is a spring pin or a parallel pin.
[0011]
  Furthermore, a fifth invention according to the present application provides a process cartridge.With the detachably attached,In an electrophotographic image forming apparatus for forming an image on a recording medium,
(A)(I) the deviceDriving from the main unitPowerA rotating shaft that is rotationally driven by
(Ii)A cylinder having a photosensitive layer on the surface;
(Iii)The rotation axisA pin provided through a through hole provided in the pin, wherein one end and the other end of the pin are connected to the rotating shaft.Rotational radius directionFrom the axis of rotationProtrusionis doingidea,
(Iv) The outer periphery of the cylinderoneMates to endAndInner circumference fits with the rotating shaft passing through the center of the cylinderWhen the rotating shaft receives the driving force from the apparatus main body, the rotating shaftRotate togetherLikeA flange member having a fitting groove for fitting with the pin,
  The fitting groove is point-symmetric with respect to the rotation center of the rotation shaft;
  Of the fitting grooveThe fitting groove is arranged such that a center line of a width on one side in the longitudinal direction is arranged at a position deviated by a distance X from the axial center of the pin in a direction opposite to the rotation direction of the cylinder by the driving force. The center line of the width on the other side in the longitudinal direction of the pin is arranged at a position that is eccentric from the axis of the pin in the direction opposite to the rotation direction of the cylinder by a distance X,
  One side protrusion provided on the side wall provided on the one side in the longitudinal direction of the fitting groove and on the upstream side in the rotation direction of the flange member, and the side wall provided with the one side protrusion A one-side protrusion that abuts the pin against the opposite side wall surface;
  The other side projection provided on the side wall surface provided on the other side in the longitudinal direction of the fitting groove and on the upstream side in the rotation direction of the flange member, and the side wall surface provided with the other side projection. The other side projection that abuts the pin against the opposite side wall surface,
HaveA flange member;
An electrophotographic photosensitive drum having
  Process means acting on the electrophotographic photosensitive drum;
A process cartridge having
(B)Conveying means for conveying the recording medium;
An electrophotographic image forming apparatus comprising:
[0012]
A sixth invention according to the present application is the electrophotographic image forming apparatus according to the fifth invention, wherein the pin is a spring pin or a parallel pin.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a multicolor image forming apparatus will be described in detail with reference to the drawings as an embodiment of an electrophotographic image forming apparatus according to the present invention.
[0014]
[Overall configuration of multicolor image forming apparatus]
First, the overall configuration of the multicolor image forming apparatus will be schematically described with reference to FIG. FIG. 1 is a longitudinal sectional view showing the overall configuration of a full-color laser beam printer which is an embodiment of a multicolor image forming apparatus.
[0015]
The multi-color image forming apparatus (hereinafter referred to as apparatus main body 100) shown in FIG. 1 includes four photosensitive drums 1 (1a, 1b, 1c, 1d) arranged in parallel in the vertical direction. The photosensitive drums 1a to 1d are driven to rotate counterclockwise in the drawing by driving means (not shown). The periphery of the photosensitive drum 1 is irradiated with a laser beam in order according to the rotation direction, and a charging device 2 (2a, 2b, 2c, 2d) for uniformly charging the surface of the photosensitive drum 1, and a laser beam based on image information, A scanner unit 3 (3a, 3b, 3c, 3d) as exposure means for forming an electrostatic latent image on the photosensitive drum 1, and a developing device 4 (developing as a toner image by attaching toner to the electrostatic latent image) 4a, 4b, 4c, 4d), an electrostatic transfer device 70 for transferring the toner image on the photosensitive drum 1 to the transfer material S, and a cleaning device 6 for removing the transfer residual toner remaining on the surface of the photosensitive drum 1 after the transfer. (6a, 6b, 6c, 6d) etc. are arranged.
[0016]
The photosensitive drum 1, the charging device 2, the developing device 4, and the cleaning device 6 are each integrally formed as a cartridge to form a process cartridge 7 that is detachable from the apparatus main body 100.
[0017]
Hereinafter, the photosensitive drum 1 will be described in detail.
[0018]
The photoconductor drum 1 is configured by applying an organic photoconductive layer (OPC photoconductor) to the outer peripheral surface of an aluminum cylinder having a diameter of 30 mm, for example. Both ends of the photosensitive drum 1 are rotatably supported by a support member (not shown), and a driving force from a drive motor (not shown) provided in the apparatus main body 100 is transmitted to one end. Thus, it is rotationally driven counterclockwise in FIG.
[0019]
As the charging device 2, a contact charging type can be used. The charging member is a conductive charging roller formed in a roller shape. The charging member is brought into contact with the surface of the photosensitive drum 1 and a charging bias voltage is applied to the charging roller to It is charged uniformly.
[0020]
The scanner unit 3 is provided in the apparatus main body 100, and is arranged in a substantially horizontal direction of the photosensitive drum 1, and image light corresponding to an image signal is rotated at high speed by a scanner motor (not shown) by a laser diode (not shown). The polygon mirror 9 (9a, 9b, 9c, 9d) is irradiated. The image light reflected by the polygon mirror 9 selectively exposes the surface of the charged photosensitive drum 1 through the imaging lens 10 (10a, 10b, 10c, 10d) to form an electrostatic latent image. It is configured as follows.
[0021]
Each of the developing devices 4a, 4b, 4c, and 4d is composed of a developing unit that stores toner of each color of yellow, magenta, cyan, and black. The developing device 4 is a device in which a developing roller 5 having a rotation shaft arranged substantially parallel to the rotation shaft of the photosensitive drum 1 is rotatably supported by the developing device, and the developer contained in the developing device is developed. The roller 5 supplies the photosensitive drum 1. Then, the developer is transferred to the photosensitive drum 1 on which the electrostatic latent image is formed, and a toner image that is a visible image is formed on the photosensitive drum 1.
[0022]
The apparatus main body 100 is provided with an electrostatic transfer belt 11 that circulates and moves so as to face and be in contact with all the photosensitive drums 1a, 1b, 1c, and 1d. The electrostatic transfer belt 11 is 10¹¹-10¹⁴It is composed of a film-like member having a volume resistivity of Ω · cm and a thickness of about 150 μm. The electrostatic transfer belt 11 is supported in the vertical direction by four rollers, and circulates so that the transfer material S is electrostatically adsorbed to the outer peripheral surface on the left side in FIG. Moving. As a result, the transfer material S is conveyed to the transfer position by the electrostatic transfer belt 11, and the toner image on the photosensitive drum 1 is transferred.
[0023]
The transfer roller 12 (12a, 12b, 12c, 12d) is arranged in parallel at a position in contact with the inside of the electrostatic transfer belt 11 and facing the four photosensitive drums 1a, 1b, 1c, 1d. A positive charge is applied from the transfer roller 12 to the transfer material S, which is a recording medium, via the electrostatic transfer belt 11, and the transfer material S in contact with the photoconductive drum 1 is applied to the photoconductive drum S by the electric field due to the charge. The negative polarity toner image on 1 is transferred.
[0024]
The electrostatic transfer belt 11 is a belt having a circumferential length of about 700 mm and a thickness of 150 μm. The belt is stretched by four rollers, that is, a driving roller 13, driven rollers 14a and 14b, and a tension roller 15. Rotate to. As a result, the above-described electrostatic transfer belt 11 circulates and the toner image is transferred while the transfer material S is conveyed from the driven roller 14a side to the drive roller 13 side.
[0025]
The paper feeding unit 16 feeds and conveys the transfer material S to the image forming unit such as the electrostatic transfer belt 11. A plurality of transfer materials S are stored in the paper feed cassette 17. At the time of image formation, the paper feed roller 18 (half-moon roller) is driven according to the image forming operation to separate and feed the transfer material S in the paper feed cassette 17 one by one. The leading edge of the transfer material S abuts against the registration roller pair 19 and temporarily stops. The rotation of the electrostatic transfer belt 11 forming a loop and the image writing position are synchronized, and the registration roller pair 19 moves to the electrostatic transfer belt 11. The paper is fed.
[0026]
The fixing unit 20 fixes a plurality of color toner images transferred to the transfer material S, and includes a heating roller 21a that rotates, and a pressure roller 21b that presses and applies heat and pressure to the transfer material S. Consists of. The transfer material S on which the toner image on the photosensitive drum 1 is transferred is conveyed by the heating roller 21a and the pressure roller 21b when passing through the fixing unit 20, and is heated and heated by the heating roller 21a and the pressure roller 21b. Given pressure. As a result, the toner images of a plurality of colors are fixed on the surface of the transfer material S.
[0027]
As an image forming operation, the process cartridges 7a, 7b, 7c, and 7d are sequentially driven in accordance with the print timing, and the photosensitive drums 1a, 1b, 1c, and 1d rotate counterclockwise in accordance with the drive. Driven. Then, the scanner units 3a to 3d corresponding to the process cartridges 7a to 7d are sequentially driven. By this driving, the charging roller provided in the charging device 2 applies a uniform charge to the peripheral surface of the photosensitive drum 1, and the scanner unit 3 exposes the peripheral surface of the photosensitive drum 1 according to the image signal. Then, an electrostatic latent image is formed on the peripheral surface of the photosensitive drum 1. The developing roller 5 in the developing device 4 transfers (develops) a toner image on the peripheral surface of the photosensitive drum 1 by transferring the developer to the low potential portion of the electrostatic latent image.
[0028]
At the timing when the leading edge of the toner image on the circumferential surface of the uppermost photosensitive drum 1 is rotated and conveyed to a point facing the electrostatic transfer belt 11, the printing start position of the transfer material S coincides with that point. The transfer material S is fed to the electrostatic transfer belt 11 by controlling the feeding of the transfer material by the rotation of the registration roller pair 19.
[0029]
The transfer material S is pressed against the outer periphery of the electrostatic transfer belt 11 so as to be sandwiched between the electrostatic adsorption roller 22 and the electrostatic transfer belt 11, and a voltage is applied between the electrostatic transfer belt 11 and the electrostatic adsorption roller 22. By applying the charge, a charge is induced in the transfer material S which is a dielectric and the dielectric layer of the electrostatic transfer belt 11, and the transfer material S is electrostatically attracted to the outer periphery of the electrostatic transfer belt 11. . As a result, the transfer material S is stably adsorbed to the electrostatic transfer belt 11 and conveyed to the most downstream transfer unit.
[0030]
While being conveyed in this manner, the toner images on the photosensitive drums 1a to 1d are sequentially transferred onto the transfer material S by an electric field formed between the photosensitive drums 1a to 1d and the transfer rollers 12a to 12d.
[0031]
The transfer material S on which the toner images of four colors are transferred is separated from the electrostatic transfer belt 11 by the curvature of the belt driving roller 13 and is carried into the fixing unit 20. After the toner image is thermally fixed by the fixing unit 20, the transfer material S is discharged from the apparatus main body 100 by the paper discharge roller pair 23 with the image surface facing down.
[0032]
(Process cartridge)
Next, the process cartridge will be described in detail.
[0033]
FIG. 2 shows a longitudinal sectional view of the process cartridge 7 in the present embodiment. A photosensitive drum 1 is attached to a cleaning unit 8a, which is a first frame, so as to be rotatable about a rotation axis. The cleaning unit 8a is provided with a cleaning blade 6f that contacts the photosensitive drum 1 and removes toner remaining on the photosensitive drum 1, and a charging roller 2f for uniformly charging the surface of the photosensitive drum 1. It has been. In addition, a conveyance member 29 for conveying the removed toner to the back of the container is provided in the container of the cleaning unit 8a.
[0034]
In FIG. 2, a developing unit 8b, which is a second frame, is attached below a cleaning unit 8a, which is a first frame. The developing unit 8b includes a developer container 30 that stores developer (toner or toner and magnetic carrier), a developing roller 5 as a developer carrying member, a developing blade 71 that regulates the amount of developer on the developing roller 5, and development. An agent supply roller 72 and an agitating member 73 for agitating the developer are provided. In the developing unit 8 b, the developer is sent from the developer container 30 to the developer supply roller 72 by the stirring member 73, and the developer is supplied to the developing roller 5 by the developer supply roller 72. Then, the thickness of the toner layer on the developing roller 5 is regulated by the developing blade 71 pressed against the outer periphery of the developing roller 5, a thin layer of developer is applied to the outer periphery of the developing roller 5 that rotates in the clockwise direction in the figure, and the development Charges the agent. The stirring member 73 has an elastic sheet-like stirring blade 74 attached to a shaft provided to be rotationally driven by the developing container 30 and rotates counterclockwise.
[0035]
The cleaning unit 8a, which is the first frame including the photosensitive drum 1, and the developing unit 8b, which is the second frame including the developing roller 5, are rotatably coupled by a coupling pin. 2, the photosensitive drum 1 and the developing roller 5 are pressed by a pressure spring 75. The position of the pressure spring 75 is located on the side opposite to the side where the photosensitive drum 1 is located when viewed from the coupling position of the cleaning unit 8a and the developing unit 8b. In the present embodiment, a compression coil spring is used as the pressure spring 75. In addition, the pressure springs 75 are provided at the left and right ends of the photosensitive drum 1 in the longitudinal direction, and the spring force of the pressure springs 75 at both ends in the longitudinal direction is substantially equal on both the left and right sides.
[0036]
Next, a method of attaching / detaching the process cartridge configured as described above to / from the apparatus main body 100 will be described with reference to FIG. Since the process cartridges 7a to 7d have the same configuration and the same method for attaching to and detaching from the apparatus main body 100, the process cartridge 7b will be described as an example, and other process cartridges 7a, 7c, and 7d may be attached and detached. Description is omitted. Further, since the left side surface 7c and the right side surface 7d of the process cartridge 7b have substantially the same configuration, only the left side surface 7c will be described and description of the right side surface 7d will be omitted.
[0037]
The process cartridge 7b is provided with a guide portion 7ba and a protruding portion 7bb. The guide portion 7ba has a convex shape protruding from the left side surface 7c of the cartridge. The guide portion 7ba is provided coaxially with the rotation shaft 50 of the photosensitive drum 1, and protrudes from the cartridge left side surface 7c.
[0038]
When the front cover 80 provided with the electrostatic transfer device 70 (see FIG. 1) of the apparatus main body 100 is opened, the guide rails 76a to 76d and 77a to 77d are visible on both the left and right sides. The guide rails 76a to 76d and 77a to 77d are grooves provided in a concave shape with respect to the inner wall surface of the apparatus main body 100. When the process cartridge 7b is mounted, the guide portion 7ba and the protruding portion 7bb are provided on the guide rail 76b. Insert it. First, the guide portion 7ba provided in the process cartridge 7b is fitted into the guide rail 76b and guided to the tip end portion 76ba of the guide rail 76b. When the guide portion 7ba reaches the distal end portion 76ba, the projection portion 7bb comes into contact with and engages with a stepped portion 76bb provided on the front side of the guide rail 76b. Further, the process cartridge 7b is positioned with respect to the apparatus main body 100 and mounted at a predetermined position by abutting the protrusion 7bb against the stepped portion 76bb with a pressure member (not shown). Then, by closing the front cover 80, the mounting of the process cartridge 7b is completed.
[0039]
When removing the process cartridge 7b from the apparatus main body 100, the process cartridge 7b can be removed by opening the front cover 80 of the apparatus main body 100 and pulling out the process cartridge 7b.
[0040]
[Embodiment 1]
Next, the photosensitive drum 1, which is a characteristic part of the present invention, will be described in detail with reference to FIGS.
[0041]
As shown in FIG. 3, the photosensitive drum 1 includes a rotating shaft 50, a hollow cylindrical cylinder 49, a front flange member 31, a rear flange member 34, and a pin 52 (which is a spring pin or a parallel pin). . The rotary shaft 50 is rotatably supported by the process cartridge 7, and an engagement hole 51 that penetrates through the diameter is provided, and a pin 52 is fitted and fixed to the engagement hole 51. The outer periphery 32 of the front flange member 31 and the outer periphery 35 of the rear flange member 34 are fitted to both ends of the cylinder 49. Each flange member 31, 34 has a collar 32 a, 35 a, and each collar 32 a, 35 a contacts the cylinder 49 so that the axial position of the flange member 31, 34 with respect to the cylinder 49 is determined. Here, the flange members 31 and 34 are fixed to the cylinder 49 by press fitting, caulking, bonding or the like. The cylinder 49, the front flange member 31, and the rear flange member 34 rotate together. The front flange member 31 includes an outer periphery 32 fitted to one end of the cylinder 49 and an inner periphery 33 fitted to the rotary shaft 50. The rear flange member 34 has an outer periphery 35 that is fitted to the other end of the cylinder 49, an inner periphery 36 that is fitted to the rotary shaft 50, a fitting groove 61 that is fitted to the pin 52, and a protrusion 62 that abuts the pin 52 on one side. It consists of
[0042]
Here, the cylinder 49 has a photosensitive layer provided on the outer periphery of an aluminum hollow cylinder having a diameter of 30 mm and a length of 260 mm. The flange members 31 and 34 are made of synthetic resin, such as polyacetal resin or polystyrene resin. The rotating shaft 50 is made of an iron material such as stainless steel, and the pin 52 is made of stainless steel or synthetic resin. As Embodiment 1, FIG. 4 shows a detailed view of the main part of the rear flange member 34a. FIG. 4 is a plan view of the rear flange member 34a. The fitting groove 61a is a concave groove formed on the end surface of the rear flange member 34a and linearly passing through the rotation center of the rotary shaft 50 in the radial direction. The width of the fitting groove 61 a in the short direction is formed to be 2X larger than the diameter of the rotating shaft 50. A center line 63a having a width on the upper side in FIG. 4 of the fitting groove 61a is disposed at a position that is offset by a distance X from the axis 53 of the pin 52 in a direction opposite to the rotation direction of the photosensitive drum 1. Since the fitting groove 61 a has a point-symmetric shape with respect to the rotation center of the rotating shaft 50, the center line 63 b of the width of the fitting groove 61 a on the lower side in FIG. 4 extends from the axis 53 of the pin 52. The photosensitive drum 1 is arranged at a position decentered by a distance X in the direction opposite to the rotation direction of the photosensitive drum 1. In other words, the backlash between the pin 52 and the fitting groove 61a is shifted to one side in the vertical direction.
[0043]
A semicircular protrusion 62a is provided on the side wall surface located upstream in the rotational direction with respect to the pin 52 of the fitting groove 61a. The protrusion 62a has a semicircular cross section at right angles to the axis, and is an axial protrusion in this cross sectional shape. When the rotary shaft 50 is fitted to the rear flange member 34a from the direction indicated by the arrow in FIG. 3 and the pin 52 is received in the fitting groove 61a, the pin 52 is provided with a projection 62a by a semicircular projection 62a. It abuts against the side wall surface opposite to the side wall surface.
[0044]
Here, the distance between the protrusion 62a tip and the fitting groove wall surface facing the tip of the protrusion 62a is smaller than the diameter of the pin 52, and the pin 52 is fitted into the fitting groove 61a with a margin. Most of the fastening allowance acts to deform the protrusion 62a.
[0045]
Thus, by providing the protrusion 62a on the side wall surface of the fitting groove 61a, the pin 52 is pressed and fixed in one direction in the fitting groove 61a, so that the play between the pin 52 and the fitting groove 61a does not move. As a result, backlash between the rotating shaft 50 and the rear flange member 34a can be prevented.
[0046]
Further, by providing the protrusion 62a on the side wall surface located on the upstream side in the rotation direction of the fitting groove 61a, when the rotary shaft 50 rotates, the side wall surface opposite to the side wall surface on which the protrusion 62a is provided is provided. The force from the pin 52 is received, and stable rotation can be obtained.
[0047]
Furthermore, by making the shape of the protrusion 62a into a semicircular shape, the contact area with the pin 52 can be reduced, and even a spring pin that varies in thickness can be easily press-fitted. The connecting operation with the rear flange member 34a is simplified.
[0048]
[Embodiment 2]
Next, as a second embodiment, a detailed view of the main part of the rear flange member 34b is shown in FIG. FIG. 5 is a plan view of the rear flange member 34b. As in the first embodiment, the fitting groove 61b is formed on the end face of the rear flange member 34b. The fitting groove 61b is a concave groove that passes through the center of rotation of the rotary shaft 50 and is linear in the radial direction. The width of the fitting groove 61b is formed to be 2X larger than the diameter of the rotating shaft 50. A center line 63a having a width on the upper side in FIG. 5 of the fitting groove 61b is disposed at a position deviated by a distance X from the axis 53 of the pin 52 in the direction opposite to the rotation of the photosensitive drum 1. Since the fitting groove 61 a has a point-symmetric shape with respect to the rotation center of the rotating shaft 50, the center line 63 b of the width of the fitting groove 61 a on the lower side in FIG. 5 extends from the axis 53 of the pin 52. The photosensitive drum 1 is disposed at a position decentered by a distance X in the direction opposite to the rotation of the photosensitive drum 1. That is, the backlash between the pin 52 and the fitting groove 61b is moved to one side in the vertical direction.
[0049]
Further, a triangular projection 62b is provided on the side wall surface located on the upstream side in the rotation direction with respect to the pin 52 of the fitting groove 61b. When the rotary shaft 50 is fitted to the rear flange member 34b from the direction indicated by the arrow in FIG. 3 and the pin 52 is received in the fitting groove 61b, the pin 52 is provided with a projection 62b by a triangular projection 62b. It abuts against the side wall surface opposite to the side wall surface.
[0050]
In the two embodiments described above, the pin 52 can be a parallel pin or a spring pin.
[0051]
According to the two embodiments described above, the rotary shaft 50 and the rear flange members 34a and 34b are fixed without rattling, and the rotary shaft 50 rotates integrally with the cylinder 49 having the photosensitive layer via the rear flange members 34a and 34b. It can drive, and the rotation nonuniformity by the play of a joint part can be reduced. In addition, since the position of the pin 52 against which the protrusions 62a and 62b abut is symmetric with respect to the rotation center of the rotation shaft 50, both sides of the pin 52 can be abutted at the same distance from the rotation center, and stable rotation can be achieved. Obtainable.
[0052]
Further, by making the protrusion 62a into a semicircular shape or making the shape of the protrusion 62b triangular, the contact area with the pin 52 can be further reduced, and even with a spring pin in which the thickness varies. It becomes possible to press-fit, and the connecting operation between the rotating shaft 50 and the rear flange member 34b is further simplified.
[0053]
【The invention's effect】
As described above, in the photosensitive drum device, since the fitting groove provided on one of the flange members fitted to the cylinder having the photosensitive layer is eccentric in the direction opposite to the rotation direction, the backlash is moved to one side. In addition, by providing a projection that abuts the pin fitted to the fitting groove on one side, the photosensitive drum device can be rotated integrally with a simple structure without rattling. Therefore, it is possible to reduce rotation unevenness of the photosensitive drum device and perform good image formation.
[0054]
  Further, according to the present invention, by providing the protrusion on the side wall surface located upstream in the rotation direction of the fitting groove, when the rotation shaft rotates, the side opposite to the side wall surface on which the protrusion is provided The wall surface receives a force from the pin, and the rotation of the photosensitive drum can be stabilized.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of a multicolor image forming apparatus according to the present invention.
FIG. 2 is a longitudinal sectional view of a process cartridge according to the present invention.
FIG. 3 is an exploded perspective view showing an embodiment of a photosensitive drum device according to the present invention.
FIG. 4 is an enlarged plan view of a main part of a rear flange member of the photosensitive drum in the first embodiment.
FIG. 5 is an enlarged plan view of a main part of a rear flange member of a photosensitive drum in a second embodiment.
FIG. 6 is a schematic view showing how the process cartridge according to the present invention is attached to and detached from the electrophotographic image forming apparatus main body.
[Explanation of symbols]
1 ... Photosensitive drum
2a to 2d ... charging device 2f ... charging roller
3a to 3d ... Scanner unit
4a to 4d ... developing device
5 ... Developing roller
6a to 6d ... Cleaning device 6f ... Cleaning blade
7 ... Process cartridge
8a: Cleaning unit 8b: Development unit
9 ... Polygon mirror
10 ... imaging lens
11 ... Electrostatic transfer belt
12 ... Transfer roller
13 ... Driving roller
14a, 14b ... driven roller
15 ... Tension roller
16: Paper feeding unit
17 ... Paper cassette
18 ... paper feed roller
19 ... Registration roller
20. Fixing part
21a ... Heating roller 21b ... Pressure roller
22 ... Electrostatic adsorption roller
23 ... Paper discharge roller pair
24: Paper discharge unit
29 ... Conveying member
30 ... Developer container
31 ... Front flange member
32 ... outer periphery 32a ... collar
33 ... Inner circumference
34 ... rear flange member 34a ... rear flange member 34b ... rear flange member
35 ... outer periphery 35a ... collar
36 ... Inner circumference
49 ... Cylinder
50 ... Rotating shaft
51 ... engagement hole
52 ... pin
53 ... axis
61 ... Fitting groove 61a ... Fitting groove 61b ... Fitting groove
62 ... Projection 62a ... Semicircular projection 62b ... Triangular projection
63a ... center line 63b ... center line
70: Electrostatic transfer device
71 ... Developing blade
72 ... Developer supply roller
73. Stirring member
74 ... Agitating blade
75 ... Pressure spring
7ba ... guide portion 7bb ... projection 7c ... process cartridge left side 7d ... process cartridge right side
76a to d, 77a to d ... guide rail 76ba ... tip portion 76bb ... step portion
80 ... Front cover
100: The apparatus main body.

Claims (6)

In a photosensitive drum device used in an electrophotographic image forming apparatus,
(I) a rotating shaft that is rotationally driven by a driving force from the main body of the electrophotographic image forming apparatus;
(Ii) a cylinder having a photosensitive layer on its surface;
And (iii) a pin provided through the through hole provided in said rotary shaft, and one end and the other end of the pin protrudes from Oite the rotary shaft in the radial direction of the rotary shaft and the pins are,
(Iv) the outer periphery is fitted to one end of the cylinder, and fitted with the rotary shaft when the inner circumference inserted through the center of said cylinder, said rotary shaft is subjected to the driving force from the apparatus main body A flange member having a fitting groove for fitting with the pin so as to rotate integrally with the rotating shaft ,
The fitting groove is point-symmetric with respect to the rotation center of the rotation shaft;
The center line of the width of one side in the longitudinal direction of the fitting groove is disposed at a position deviated by a distance X from the axis of the pin in a direction opposite to the rotation direction of the cylinder by the driving force, and The center line of the width of the other side in the longitudinal direction of the fitting groove is arranged at a position deviated by a distance X from the shaft center of the pin in a direction opposite to the rotation direction of the cylinder. And
One side protrusion provided on the side wall provided on the one side in the longitudinal direction of the fitting groove and on the upstream side in the rotation direction of the flange member, and the side wall provided with the one side protrusion A one-side protrusion that abuts the pin against the opposite side wall surface;
The other side projection provided on the side wall surface provided on the other side in the longitudinal direction of the fitting groove and on the upstream side in the rotation direction of the flange member, and the side wall surface provided with the other side projection. The other side projection that abuts the pin against the opposite side wall surface,
A flange member having
A photosensitive drum device.   The photosensitive drum device according to claim 1, wherein the pin is a spring pin or a parallel pin. In a process cartridge that is detachably attached to an apparatus main body of an electrophotographic image forming apparatus,
(A) (i) a rotating shaft that is rotationally driven by a driving force from the apparatus main body;
(Ii) a cylinder having a photosensitive layer on its surface;
And (iii) a pin provided through the through hole provided in said rotary shaft, and one end and the other end of the pin protrudes from Oite the rotary shaft in the radial direction of the rotary shaft and the pins are,
(Iv) the outer periphery is fitted to one end of the cylinder, fitted with the rotary shaft when the inner circumference inserted through the center of said cylinder, said rotary shaft is subjected to the driving force from the apparatus main body A flange member having a fitting groove for fitting with the pin so as to rotate integrally with the rotating shaft ,
The fitting groove is point-symmetric with respect to the rotation center of the rotation shaft;
The center line of the width of one side in the longitudinal direction of the fitting groove is disposed at a position deviated by a distance X from the axis of the pin in a direction opposite to the rotation direction of the cylinder by the driving force, and The center line of the width of the other side in the longitudinal direction of the fitting groove is arranged at a position deviated by a distance X from the shaft center of the pin in a direction opposite to the rotation direction of the cylinder. And
One side protrusion provided on the side wall provided on the one side in the longitudinal direction of the fitting groove and on the upstream side in the rotation direction of the flange member, and the side wall provided with the one side protrusion A one-side protrusion that abuts the pin against the opposite side wall surface;
The other side projection provided on the side wall surface provided on the other side in the longitudinal direction of the fitting groove and on the upstream side in the rotation direction of the flange member, and the side wall surface provided with the other side projection. The other side projection that abuts the pin against the opposite side wall surface,
A flange member having
An electrophotographic photosensitive drum having
(B) process means acting on the electrophotographic photosensitive drum;
A process cartridge comprising:   The process cartridge according to claim 3, wherein the pin is a spring pin or a parallel pin. In an electrophotographic image forming apparatus for forming an image on a recording medium with a process cartridge detachably mounted ,
(A) (i) a rotating shaft that is rotationally driven by a driving force from the apparatus main body;
(Ii) a cylinder having a photosensitive layer on its surface;
And (iii) a pin provided through the through hole provided in said rotary shaft, a pin and one end and the other end of the pin projects from the rotary shaft in the radial direction of the rotary shaft ,
(Iv) the outer periphery is fitted to one end of the cylinder, and fitted with the rotary shaft when the inner circumference inserted through the center of said cylinder, said rotary shaft is subjected to the driving force from the apparatus main body A flange member having a fitting groove for fitting with the pin so as to rotate integrally with the rotating shaft ,
The fitting groove is point-symmetric with respect to the rotation center of the rotation shaft;
The center line of the width of one side in the longitudinal direction of the fitting groove is disposed at a position deviated by a distance X from the axis of the pin in a direction opposite to the rotation direction of the cylinder by the driving force, and The center line of the width of the other side in the longitudinal direction of the fitting groove is arranged at a position deviated by a distance X from the shaft center of the pin in a direction opposite to the rotation direction of the cylinder. And
One side protrusion provided on the side wall provided on the one side in the longitudinal direction of the fitting groove and on the upstream side in the rotation direction of the flange member, and the side wall provided with the one side protrusion A one-side protrusion that abuts the pin against the opposite side wall surface;
The other side projection provided on the side wall surface provided on the other side in the longitudinal direction of the fitting groove and on the upstream side in the rotation direction of the flange member, and the side wall surface provided with the other side projection. The other side projection that abuts the pin against the opposite side wall surface,
A flange member having
An electrophotographic photosensitive drum having
Process means acting on the electrophotographic photosensitive drum;
A process cartridge having
(B) transport means for transporting the recording medium;
An electrophotographic image forming apparatus comprising:   6. The electrophotographic image forming apparatus according to claim 5, wherein the pin is a spring pin or a parallel pin.

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