JP2006251463A - Process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process cartridge which has the number of drum shaft working processes reduced and has less variance of a rotation speed with respect to drive transmission between a drum shaft and a drive input means. <P>SOLUTION: The process cartridge attachable to and detachable from an image forming apparatus main body, which has at least a photoreceptor drum, a drum flange, the drum shaft, and the drive input means, includes; a first and a second through holes installed in a direction orthogonal to an axis of rotation; a third through hole provided in a lengthwise position corresponding to the through hole installed in the drum flange, in the drum shaft; a fourth through hole provided in a lengthwise position corresponding to the through hole installed in the drive input means, in the drum shaft, a first pin engaged with the first through hole provided in the drum flange and the third through hole provided on the drum shaft, and a second pin engaged with the second through hole provided in the drive input means and the fourth through hole provided in the drum shaft. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

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

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

  The process cartridge (hereinafter referred to as “cartridge”) is a cartridge in which at least the developing means (developing member) and the electrophotographic photosensitive drum are integrated into a cartridge so as to be detachable from the main body of the electrophotographic image forming apparatus. To tell.

  Conventionally, in an electrophotographic image forming apparatus (hereinafter referred to as “image forming apparatus”), an electrostatic latent image formed on an electrophotographic photosensitive drum (hereinafter referred to as “photosensitive drum”) is developed by a developing device. Develop with an agent.

  Also, in an image forming apparatus that employs a process cartridge, the operator can perform maintenance of the apparatus himself, and this cartridge system can greatly improve operability.

  In such a process cartridge, the photosensitive drum is provided with a flange member at both ends, and a drum shaft penetrating the photosensitive drum is attached via the flange member, and the drum shaft is connected to the process cartridge via a bearing member. It is positioned so as to be rotatable on the frame. Drive input means for transmitting drive from the image forming apparatus main body is attached to the drum shaft.

  Here, as a method of transmitting the drive from the drive input means to the shaft member, a D-cut shape is provided in a fitting portion between the drive input means and the drum shaft, and press fitting or provided in the drum shaft and the drive input means. This is done by press-fitting a pin into the formed through hole.

JP 2004-86182 A (page 15, FIG. 8)

  The present invention is a further development of the aforementioned prior art.

  An object of the present invention is to provide a process cartridge that reduces the number of drum shaft machining steps and has a small rotational speed variation with respect to drive transmission between the drum shaft and drive input means.

  In order to achieve the above object, the present invention provides at least a photosensitive drum, a drum flange fixed to the photosensitive drum, a drum shaft engaged with the drum flange, and a drum shaft driven from the image forming apparatus main body. In the process cartridge detachably attachable to the image forming apparatus main body having a drive input means for transmitting the first input hole, a first through hole installed in the drum flange in a direction perpendicular to the rotation axis, and the rotation axis in the drive input means. A second through hole installed in an orthogonal direction; a third through hole provided in a longitudinal position corresponding to the through hole installed in the drum flange in the drum shaft; and the drive input in the drum shaft. A fourth through hole provided in a longitudinal position corresponding to the through hole provided in the means, a first through hole provided in the drum flange, and A first pin that engages with a third through hole provided in the drum shaft, a second through hole provided in the drive input means, and a fourth through hole provided in the drum shaft And the flange, the drum shaft, the drive input means, and the drum shaft are fixed by press-fitting the pin into the through hole.

  According to the present invention, it is possible to eliminate backlash at the fitting portion between the drum shaft and the drive input means, and it is possible to perform drive transmission with little fluctuation in rotational speed. Further, since the number of drum shaft machining steps can be reduced, the manufacturing cost is reduced.

  The best mode for carrying out the present invention will be exemplarily described below with reference to the drawings. However, the materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. Further, the materials, shapes, etc. of the members once described in the following description are the same as those in the first description unless otherwise described.

The process cartridge and the image forming apparatus according to the present embodiment will be described with reference to FIGS.
[Overall Description of Image Forming Apparatus]
First, the overall configuration of the color image forming apparatus will be described with reference to FIG.

  FIG. 2 is a schematic cross-sectional view of a color laser printer which is an embodiment of an image forming apparatus using an electrophotographic process according to the present embodiment.

  As shown in FIG. 2, a color laser printer (hereinafter referred to as “printer”) 100 is a photosensitive that rotates at a constant speed for each color of yellow (Y), magenta (M), cyan (C), and black (K). An image forming unit having a process cartridge 7 (7Y, 7M, 7C, 7K) having a body drum 1 (1Y, 1M, 1C, 1K) and a recording medium P fed from the feeding unit are developed in the image forming unit. The image forming apparatus includes a transfer unit that multiplex-transfers the image that has been transferred, a fixing unit that fixes the image onto the recording medium P to which the color image has been transferred, and a discharge unit that discharges the recording medium P to the upper surface of the apparatus. The four color process cartridges 7Y, 7M, 7C, and 7K are configured to be detachable from the printer main body 100 individually.

  A charging roller 2 (2Y, 2M, 2C, 2K) as a charging member for uniformly charging the surface of the photosensitive drum 1 in order according to the rotation direction, and a laser beam based on the image information around the photosensitive drum 1. It has a scanner unit 3 (3Y, 3M, 3C, 3K) that irradiates and forms an electrostatic latent image on the photosensitive drum 1 charged by the charging roller 2.

Further, it has a developing unit 4 (4Y, 4M, 4C, 4K) for developing the latent image. And it has the transfer roller 12 (12Y, 12M, 12C, 12K) which transfers the developer image on each photoconductive drum 1 to the recording medium P by the transfer part T. A cleaning unit 6 (6Y, 6M, 6C, 6K) having a cleaning blade 60 for removing the developer remaining on the surface of the photosensitive drum 1 after the transfer is disposed. The transfer roller 12 is provided in the image forming apparatus main body A. The image forming apparatus main body A includes an electrostatic conveyance belt 5 that electrostatically attracts and conveys the recording medium P.

  The recording medium P to which the developer image has been transferred is fixed with the developer image in the fixing device 8. Then, the paper is discharged to the discharge tray 26 on the upper surface of the apparatus by the discharge roller pair 25.

  The cartridge 7 includes the photosensitive drum 1, the charging member 2, the developing unit 4, and the cleaning unit 6 described above. Further, the printer 100 has an open / close cover 11 (FIG. 3) integrated with the electrostatic conveyance belt 5. The cartridge 7 is attached to and detached from the printer 100 with the photosensitive drum 1 facing forward with the opening / closing cover 11 opened.

  Hereinafter, the photosensitive drum 1 will be described in detail.

  The photoconductor drum 1 is configured by applying an organic photoconductive layer (OPC photoconductor) to an outer peripheral surface of an aluminum cylinder having a diameter of 24 mm, for example. The photosensitive drum 1 is rotatably supported at both ends by a support member, and is driven to rotate counterclockwise by transmitting a driving force from a driving motor (not shown) to one end. The

  As the charging device 2, a conductive charging roller 2 formed in a roller shape is used as a charging member using a contact charging method. The charging roller 2 is brought into contact with the surface of the photosensitive drum 1 and a charging bias voltage is applied to the charging roller 2 to uniformly charge the surface of the photosensitive drum 1.

  A scanner unit 3 as exposure means is arranged in a substantially horizontal direction of the photosensitive drum 1, and a polygon mirror in which image light corresponding to an image signal is rotated at high speed by a scanner motor (not shown) by a laser diode (not shown). 9 (9Y, 9M, 9C, 9K). The image light reflected by the polygon mirror 9 selectively exposes the surface of the charged photosensitive drum 1 through the imaging lens 10 (10Y, 10M, 10C, 10K) to form an electrostatic latent image. It is composed.

  The developing unit 4 includes a toner container 41 (41Y, 41M, 41C, 41K) as a developing container as shown in FIG. 4 in which toner of each color of yellow, magenta, cyan, and black is stored. The toner inside is fed to the toner supply roller 43 by the toner transport mechanism 42. Thereafter, toner is applied to the outer periphery of the developing roller 40 that rotates clockwise by the toner supply roller 43 that rotates clockwise and the developing blade 44 that is in pressure contact with the outer periphery of the developing roller 40 as a developer carrier, and The toner is charged. Then, by applying a developing bias to the developing roller 40 facing the photosensitive drum 1 on which the electrostatic latent image is formed, toner development is performed on the photosensitive drum 1 in accordance with the electrostatic latent image. is there.

  An electrostatic conveyance belt 5 that circulates and moves so as to face and contact all the photosensitive drums 1Y, 1M, 1C, and 1K is disposed. The electrostatic conveyance belt 5 is composed of a film-like member having a predetermined volume specific resistance. The electrostatic conveyance belt 5 is supported by rollers in four directions in the vertical direction, and circulates and moves so that the recording medium P is electrostatically attracted to the outer peripheral surface on the left side in the drawing to bring the recording medium P into contact with the photosensitive drum 1. . As a result, the recording medium P is transported to the transfer position by the electrostatic transport belt 5 and the toner image on the photosensitive drum 1 is transferred.

  The transfer roller 12 (12Y, 12M, 12C, 12K) is arranged in parallel at a position in contact with the inside of the electrostatic conveyance belt 5 and facing the four photosensitive drums 1Y, 1M, 1C, 1K. A positive charge is applied from the transfer roller 12 to the recording medium P via the electrostatic conveyance belt 5, and the electric field generated by the charge causes the recording medium P in contact with the photosensitive drum 1 to be moved onto the photosensitive drum 1. A negative toner image is transferred.

  The feeding unit 16 feeds the recording medium P to the image forming unit, and a plurality of recording media P are stored in the feeding cassette 17. At the time of image formation, the feeding roller 18 (half-moon roller) and the registration roller pair 21 are driven and rotated according to the image forming operation to separate and feed the recording media P in the feeding cassette 17 one by one. The leading end abuts against the registration roller pair 21 and temporarily stops, forms a loop, synchronizes the rotation of the electrostatic conveyance belt 5 and the image writing position, and is fed to the electrostatic conveyance belt 5 by the registration roller pair 21. Go.

  The fixing device 8 fixes the toner images of a plurality of colors transferred to the recording medium P, a heating roller 23 that rotates, and a pressure roller 24 that presses against the heating roller 23 and applies heat and pressure to the recording medium P. Consists of. That is, the recording medium P to which the toner image on the photosensitive drum 1 is transferred is conveyed by the heating roller 23 and the pressure roller 24 and is given heat and pressure when passing through the fixing device 8. As a result, toner images of a plurality of colors are fixed on the surface of the recording medium P.

  As an image forming operation, the process cartridge 7 is sequentially driven in accordance with the print timing, and the photosensitive drum 1 is driven to rotate counterclockwise in accordance with the drive. Then, the scanner units 3 corresponding to the respective process cartridges 7 are sequentially driven. By this driving, the charging roller 2 imparts a uniform charge to the circumferential surface of the photosensitive drum 1, and the scanner unit 3 exposes the circumferential surface of the photosensitive drum 1 according to the image signal to perform photosensitive drum 1. An electrostatic latent image is formed on the peripheral surface. The developing roller 40 in the developing device 4 forms (develops) a toner image on the circumferential surface of the photosensitive drum 1 by transferring the toner to the low potential portion of the electrostatic latent image.

  At the timing when the leading edge of the toner image on the circumferential surface of the most upstream photosensitive drum 1 (photosensitive drum 1Y in the drawing) is rotationally conveyed to a point facing the electrostatic conveying belt 5, the recording medium is placed at the opposite point. The registration roller pair 21 starts rotating and feeds the recording medium P to the electrostatic conveyance belt 5 so that the printing start positions of P coincide.

  The recording medium P is pressed against the outer periphery of the electrostatic conveyance belt 5 so as to be sandwiched between the electrostatic adsorption roller 22 and the electrostatic conveyance belt 5, and between the electrostatic conveyance belt 5 and the electrostatic adsorption roller 22. By applying a voltage, a charge is induced in the recording medium P that is a dielectric and the dielectric layer of the electrostatic conveyance belt 5, and the recording medium P is electrostatically attracted to the outer periphery of the electrostatic conveyance belt 5. ing. As a result, the recording medium P is stably adsorbed to the electrostatic conveyance belt 5 and conveyed to the most downstream transfer unit. While being conveyed in this manner, the toner image on each photosensitive drum 1 is sequentially transferred to the recording medium P by an electric field formed between each photosensitive drum 1 and the transfer roller 12.

The recording medium P to which the four color toner images are transferred is separated from the electrostatic conveyance belt 5 by the curvature of the belt driving roller 14 and is carried into the fixing device 8. After the toner image is thermally fixed by the fixing device 8, the recording medium P is discharged out of the main body by the discharge roller pair 25 with the image surface facing down from the discharge tray 26.
[Removal of process cartridge]
Next, a method of attaching / detaching the cartridge 7 to / from the image forming apparatus 100 will be described with reference to FIG.

The opening / closing cover 11 of the image forming apparatus 100 has a rotation center on the lower front side of the image forming apparatus 100. The electrostatic cover belt 5 is provided on the opening / closing cover 11. Therefore, when the opening / closing cover 11 is opened, the operator can access the cartridges 7Y, 7M, 7C, and 7K. The cartridge 7 is configured to be inserted and removed in the horizontal direction when the open / close cover 11 of the image forming apparatus 100 is opened.
[Process cartridge configuration]
Next, the configuration of the cartridge 7 will be described with reference to FIGS. 4 is a main cross section of the cartridge 7 containing the developer t, and FIG. 5 is a perspective view thereof. However, FIG. 5 illustrates a state in which the developing unit 4 and the cleaning unit 6 are disassembled.

  As shown in FIG. 3, the cartridge 7 includes a drum-shaped electrophotographic photosensitive member, that is, an electrophotographic photosensitive drum 1, a cleaning unit 6 including a charging roller 2 and a cleaning blade 60, and a static on the photosensitive drum 1. The developing unit 4 includes a developing roller 40 that develops the electrostatic latent image.

  The photosensitive drum 1 is rotatably attached to the cleaning unit 6 via a bearing member (cartridge positioning member) 31. A charging roller 2 for uniformly charging the surface of the photosensitive drum 1 and a cleaning blade 60 for removing the developer remaining on the photosensitive drum 1 are disposed on the peripheral surface of the photosensitive drum 1. Yes.

  The developer removed from the surface of the photosensitive drum 1 by the cleaning blade 60 is sequentially sent to a waste developer chamber 63 provided behind the drum unit frame 61 by the developer feeding mechanism 62.

  The photosensitive drum 1 is rotated counterclockwise according to the image forming operation by receiving the driving force of a driving motor (not shown) provided in the image forming apparatus main body A.

  The developing unit 4 includes a developing roller 40 that rotates in contact with the photosensitive drum 1 (in the direction of arrow Y), a developer container 41 that stores the developer, and a developing container 45. The developing roller 40 is rotatably supported by the developing container 45 via developing bearings 47 and 48. Further, on the peripheral surface of the developing roller 40, a developer supply roller 43 and a developing blade 44 that are in contact with the developing roller 40 and rotate (in the direction of arrow Z) are arranged. Further, a developer transport mechanism 42 for stirring the stored developer and transporting the developer to the developer supply roller 43 is provided in the developer storage section 41.

  As shown in FIG. 5, the developing unit 4 is cleaned by the pins 50 around the support holes 49 provided in the developing bearings 47 and 48 attached to both ends of the developing unit 4. The unit 6 is supported so as to be swingable.

  When the cartridge 7 is a single unit (not attached to the apparatus main body A), a pressure spring is applied so that the developing roller 40 is urged toward the photosensitive drum 1 by a rotational moment about the support shaft 50. The developing unit 4 is always urged by 64.

  During development, the developer agitation member 42 conveys the stored developer to the developer supply roller 43. Then, the rotating developer supply roller 43 (in the arrow Z direction) supplies the developer to the developing roller 40 by rubbing against the rotating developing roller 40 (in the arrow Y direction). Then, the developer is carried on the peripheral surface of the developing roller 40. The developer carried on the developing roller 40 reaches the developing blade 44 as the developing roller 40 rotates. Then, the developing blade 44 imparts a charge to the developer. As a result, a predetermined developer thin layer is formed on the peripheral surface of the developing roller 40, and the developer is conveyed to the developing unit where the photosensitive drum 1 and the developing roller 40 are in contact with each other. In the developing unit, a developer is formed on the surface of the photosensitive drum 1 by a DC developing bias applied to the developing roller 40 from a power source (not shown) of the image forming apparatus 100 via a developing / supply electrical contact (not shown). The latent image is developed by adhering to the electrostatic latent image.

  The developer remaining on the surface of the developing roller 40 without contributing to the development is returned to the developing device as the developing roller 40 rotates. Then, it is peeled off and collected from the developing roller 40 at the rubbing portion with the developer supply roller 43. The collected developer is stirred and mixed with the remaining developer by the developer stirring mechanism 42.

  Next, the configuration around the photosensitive drum according to the present invention will be described in detail with reference to FIGS. In the following description, a and b at the end of the symbol may be omitted in the case of the same configuration on the left and right.

  FIG. 1 is a cross-sectional view of the support structure of the photosensitive drum in the present embodiment.

  In the photosensitive drum 1, the outer periphery of the shaft 201 is fitted into the inner periphery of the bearing members 31 a and 31 b, and the outer periphery of the bearing members 31 a and 31 b is fitted into the bearing mounting portion 231 that is a recess provided in the cleaning frame body 61. Thereby, the photosensitive drum 1 is positioned so as to be rotatable with respect to the cleaning frame 61. For the bearing member 31, for example, a ball bearing or a sliding bearing such as a sintered material can be used. Rotation drive is transmitted from a drive transmission means (not shown) of the image forming apparatus main body to a drive input means of the process cartridge to rotate the photosensitive drum. A gear, a coupling, or the like is used for the drive input means.

  As shown in FIG. 1, the photosensitive drum 1 has a flange 200 (200a, 200b) fixed to both ends of an aluminum cylindrical member 1a having a photosensitive layer formed on its peripheral surface by a method such as adhesion or caulking. A shaft 201 is fitted in the center holes of the flanges 200a and 200b. A shaft 201 is a penetrating shaft, and one end and the other end protrude outward from the photosensitive drum 1 through the aluminum cylindrical member 1a. The shaft 201 is a conductive metal rod.

  The flange 200b and the drum shaft 201 are press-fitted and fixed by inserting a pin 202b into the through holes 200c and 201b. The drum shaft 201 and the drive input means 30 are also press-fitted and fixed by inserting pins 202a into the through holes 30a and 201a. As a result, the drum shaft 201 and the flange 200b and the drum shaft 201 and the drive input means 30 can rotate integrally. A metal parallel pin, a spring pin, or the like is used for the pin 202 from the viewpoint of strength. Conventionally, as shown in FIG. 7, the engagement portion between the drum shaft and the drive input means has a D-cut shape, and is press-fitted or pressed into a through-hole provided in the drum shaft and the drive input means. Fixed.

  According to the fixing method of the present invention, it is not necessary to cut the D-cut portion on the shaft, the shape of the drum shaft 201 can be simplified, and the manufacturing cost can be reduced. Furthermore, if the through holes 201a and 201b provided in the drum shaft 201 are made substantially parallel, the through holes 201a and 201b can be processed from the same direction in the manufacturing process of the drum shaft 201, so there is no need to change the shaft. Manufacturing costs can be reduced.

FIG. 2 is a cross-sectional view illustrating a schematic configuration around a photosensitive drum according to an embodiment of the present invention. 1 is a schematic cross-sectional view of a color laser printer which is an embodiment of an image forming apparatus using an electrophotographic process. 1 is a schematic cross-sectional view of a color laser printer which is an embodiment of an image forming apparatus using an electrophotographic process. It is sectional drawing which shows schematic structure of a process cartridge. It is a disassembled perspective view which shows schematic structure of a process cartridge. FIG. 2 is a perspective view showing a schematic configuration around a photosensitive drum according to an embodiment of the present invention. It is the schematic of the drive input means fixing method of a prior art example.

Explanation of symbols

1 Photosensitive drum 2 Charging roller (charging member)
DESCRIPTION OF SYMBOLS 3 Scanner unit 4 Developing unit 5 Electrostatic conveyance belt 6 Cleaning unit 7 Process cartridge 8 Fixing device 9 Polygon mirror 10 Imaging lens 11 Opening / closing cover 12 Transfer roller 13 Drive roller 14 Driving roller 16 Tension roller 17 Feed cassette 18 Feed roller DESCRIPTION OF SYMBOLS 19 Separation pad 21 Registration roller pair 22 Electrostatic adsorption roller 23 Heating roller 24 Pressure roller 25 Discharge roller pair 26 Discharge tray 30 Driving force receiving part 31 Bearing member 40 Developing roller (developing member)
DESCRIPTION OF SYMBOLS 41 Developer accommodating part 42 Conveying member 43 Supply roller 44 Developing blade 45 Developing frame body 46 Helical gear 47 Developing bearing 49 Supporting hole 50 Support shaft 55 Memory unit 56 Communication unit 60 Cleaning blade 61 Cleaning frame body 62 Developer feeding mechanism 63 Accommodating chamber 64 Pressurizing spring 81 Cartridge rotation restricting portion 91 Charging electrical contact 92 Development / supply electrical contact 93 Developing blade electrical contact 100 Electrophotographic image forming apparatus (printer)
200 Flange 201 Drum shaft 202 Pin A Electrophotographic image forming apparatus main body t Developer

Claims (3)

Image formation comprising at least a photosensitive drum, a drum flange fixed to the photosensitive drum, a drum shaft engaged with the drum flange, and a drive input means for transmitting drive from the image forming apparatus main body to the drum shaft. In a process cartridge that can be attached to and detached from the main body,
A first through hole installed in the drum flange in a direction orthogonal to the rotation axis, a second through hole installed in the drive input means in a direction orthogonal to the rotation axis, and the drum flange in the drum shaft A third through-hole provided at a longitudinal position corresponding to the through-hole installed in the first through-hole, and a fourth through-hole provided at a longitudinal position corresponding to the through-hole installed in the drive input means on the drum shaft A first pin that engages with a first through hole provided in the drum flange and a third through hole provided in the drum shaft; a second through hole provided in the drive input means; And a second pin that engages with a fourth through hole provided in the drum shaft, and the flange, the drum shaft, the drive input means, and the drum shaft are fixed by press-fitting the pin into the through hole. That The process cartridge according to claim.   2. The process cartridge according to claim 1, wherein the first and second pins are spring pins and are press-fitted and fixed in the through holes.   The process cartridge according to claim 1, wherein the third and fourth through holes provided in the drum shaft are substantially parallel.

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