JP2006292869A - Process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process cartridge that stabilizes a separating mechanism for a photoreceptor drum and a developing roller and simplifies the constitution of an image forming apparatus body with simple constitution. <P>SOLUTION: The process cartridge which can be loaded in and unloaded from the electrophotographic image forming apparatus body has a cleaning unit, a developing unit comprising a developing roller and a developing frame body which stores toner and holds the developing roller in one body, and a coupling part which couples the cleaning unit and developing unit in a swingable state, and the developing unit has a force reception part downstream in a loading direction wherein the process cartridge applied with a force from the image forming apparatus body is loaded in the image forming apparatus body. The force reception part is pushed to move to swing the developing unit around the coupling part, and the photoreceptor drum and developing roller are separated, and the force reception part is provided at nearly a central part in the longitudinal direction of the developing unit. <P>COPYRIGHT: (C)2007,JPO&INPIT

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.

  This type of process cartridge type image forming apparatus forms an image on a recording medium using a developer. In a so-called contact development method in which development is performed by bringing a developing roller for supplying developer stored in a developer storage unit into contact with a photosensitive drum, and development is performed, generally, a conductive substrate is placed on a conductive substrate rather than the substrate. One or more types of resistance layers having a high electric resistance value are provided, and the resistance layers are in contact with the photosensitive drum.

  Further, in order to make the developable area between the developing roller and the photosensitive drum uniform, the developing roller is constantly pressed against the photosensitive drum by a biasing means such as a spring. A developing unit having a developing roller and a cleaning unit having a photosensitive drum are configured to be rotatably coupled.

In the contact development method, development separation is performed in the main body of the image forming apparatus in order to prevent the following problems.
(1) When the photosensitive drum rotates at a timing other than during the developing operation such as pre-rotation and post-rotation, the surface layer of the photoconductor is scraped by sliding with the developing roller, which becomes a factor of reducing the life.
(2) When other color cartridges not involved in development are operated, such as during mono-color development, the life of the photoreceptor is reduced.
(3) When no bias is applied during non-operation, pre-rotation, and post-rotation, the developer on the developing roller adheres to the photoconductor, wastes the developer, or the developer stains paper or the like Cause.
(4) The roller layer of the developing roller is permanently deformed when it is not used for a long time while it is mounted in the image forming apparatus main body, which causes unevenness on the image during development.

  In order to prevent the above-described problem, as in Patent Document 1, in the image forming apparatus main body, a force receiving portion provided in the developing unit is pressed by a separating unit included in the image forming apparatus main body except during development. A configuration for separating the developing roller and the photosensitive drum has been proposed and has already been implemented.

JP 2003-215876 A (page 7, FIG. 9)

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

  Accordingly, an object of the present invention is to provide a process cartridge that stabilizes the separation mechanism between the photosensitive drum and the developing roller with a simple configuration and simplifies the configuration of the image forming apparatus main body.

  In order to achieve the above object, the present invention provides a process cartridge that is attachable to and detachable from an electrophotographic image forming apparatus main body, and includes a cleaning unit having a photosensitive drum and a frame that supports the photosensitive drum, and a photosensitive drum. A developing unit that integrates a developing roller for developing the electrostatic latent image and a developing frame that holds toner to be supplied to the developing roller and holds the developing roller, the cleaning unit, and the developing unit A coupling portion that couples the unit in a swingable manner; and a force receiving portion on the downstream side in the mounting direction in which the process cartridge to which a force is applied from the image forming apparatus body is mounted on the developing unit. Then, when the force receiving portion is pressed, the force receiving portion moves and the developing unit swings around the coupling portion, Spaced light drum and the developing roller, the force receiving portion and being provided in the substantially longitudinal center portion of the developing unit.

  According to the present invention, it is not necessary to provide a plurality of separating means in the longitudinal direction of the process cartridge, and the configuration of the image forming apparatus main body can be simplified. Further, since the force receiving portion is provided in the substantially central portion in the longitudinal direction, a stable separation distance can be obtained with respect to the set separation distance between the photosensitive drum and the developing roller, and the separation between the photosensitive drum and the developing roller can be obtained. The distance can be substantially the same at both ends in the longitudinal direction.

  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. 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.

A process cartridge and an 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 sectional view of a color laser printer which is an embodiment of an image forming apparatus using the electrophotographic process according to the present embodiment.

  As shown in FIG. 2, a color laser printer (hereinafter referred to as “printer”) 100 is a photoreceptor that rotates at a constant speed for each color of yellow (Y), magenta (M), cyan (C), and black (K). The image forming unit having the process cartridge 7 (7Y, 7M, 7C, 7K) having the drum 1 (1Y, 1M, 1C, 1K) and the recording medium P fed from the feeding unit are developed in the image forming unit. A transfer unit that multiplex-transfers the image, a fixing unit that fixes the image to 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 in accordance with an image signal to perform the photosensitive drum. An electrostatic latent image is formed on one circumferential 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 figure) is rotationally conveyed to the opposite point to the electrostatic conveyance belt 5, the recording medium P is located at the opposite point. The registration roller pair 21 starts to rotate so that the printing start positions coincide with each other to feed the recording medium P to the electrostatic conveyance belt 5.

  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 for attaching and detaching the cartridge 7 to and from the image forming apparatus 100 will be described with reference to FIGS. FIG. 3 is a schematic cross-sectional view of a color laser printer which is an embodiment of an image forming apparatus using an electrophotographic process, and FIG. 4 is a partial cross-section showing a positioning portion of the process cartridge according to the embodiment of the present invention to the image forming apparatus. 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 / removed in the horizontal direction when the open / close cover 11 of the image forming apparatus 100 is opened.

  As shown in FIG. 4, guide members 102 are attached to the inner walls of the left and right main body side plates 106. The guide member 102 is provided with a horizontal guide rib 103 that is open on the right side in the drawing. Dowels 65 that fit into the guide ribs 103 are provided on both longitudinal sides of the cleaning frame 61.

  The process cartridge 7 is inserted from the right to the left in FIG. 4 and the dowel 65 is fitted to the guide rib 103 and moves left. When the process cartridge 7 is mounted on the image forming apparatus main body A, the photosensitive drum 1 is supported on the image forming apparatus main body A by the cleaning frame 61 and the exposed portion of the bearing member 31 where a part of the outer peripheral surface is exposed. Is performed by directly engaging the main body positioning portion 105. The main body positioning unit 105 is directly provided on the sheet metal frame 106 of the image forming apparatus main body A. Therefore, when the process cartridge 7 is mounted on the image forming apparatus main body A, the process cartridge 7 is positioned with respect to the image forming apparatus main body A with the photosensitive drum 1 as the center. Here, the main body positioning configuration is the same on both longitudinal sides of the process cartridge.

Further, the cartridge pressing lever 104 of the image forming apparatus main body A presses the cartridge pressurizing portion 66 that is the outer peripheral surface of the bearing of the cleaning frame 61 in which the bearing member 31 is fitted, whereby the process cartridge 7 is moved to the image forming apparatus. It can be securely held at the image forming position of the main body A.
[Process cartridge configuration]
Next, the configuration of the cartridge 7 will be described with reference to FIGS.

  5 is a main cross section of the cartridge 7 containing the developer t, and FIG. 6 is a perspective view thereof. 7A and 7B are perspective views showing the relationship between the photosensitive drum and the developing roller according to the embodiment of the present invention, in which FIG. 7A shows a state in which the development separation is released, and FIG. 7B shows a state in which the development separation is released. . However, FIG. 6 illustrates a state in which the developing unit 4 and the cleaning unit 6 are disassembled.

  As shown in FIG. 5, 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 rotates 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. 4, 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.

  As a result, the photosensitive drum 1 and the developing roller 40 are urged by a moment about the pin 50 as shown in FIG. 7, and are applied to the longitudinal ends of the developing roller 40 and the developing roller 40 with respect to the photosensitive drum 1. A roller member having an outer diameter equal to or smaller than the outer diameter of the developing roller 40 is pressed. In this manner, the developing unit 4 swings the developing roller 40 toward the photosensitive drum 1 around the pin 50 by the urging force of the pressure spring 64, so that the developing roller 40 is formed on the developing roller 40 as shown in FIG. The rubber layer 40b made of an elastic material such as rubber is compressed to a position where the roller member 200 abuts against the photosensitive drum 1, thereby creating a developable region.

  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 that does not contribute to the development and remains on the surface of the developing roller 40 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 development separation structure according to the present invention will be described in detail with reference to FIGS. 1, 2, and 8 to 11.

FIG. 1 is a perspective view of a process cartridge according to an embodiment of the present invention. FIG. 2 is a schematic sectional view of a color laser printer which is an embodiment of an image forming apparatus using an electrophotographic process (all color separation release state). 8 is a cross-sectional view schematically showing the state of development separation release according to the embodiment of the present invention, FIG. 9 is a cross-sectional view schematically showing the state of development separation according to the embodiment of the present invention, and FIG. 10 is an electrophotographic process. FIG. 11 is a schematic cross-sectional view of a color laser printer that is an embodiment of an image forming apparatus using an electrophotographic process. FIG. 11 is a schematic cross-sectional view of a color laser printer that is an embodiment of an image forming apparatus using an electrophotographic process. FIG. 12 is a bottom view of the developing frame according to the embodiment of the present invention.
<Development separation configuration>
On the downstream side of the image forming apparatus main body 100 in the process cartridge insertion direction, as shown in FIGS. 8 and 9, a separating unit for separating the developing roller 40 from the photosensitive drum 1 against the urging force of the developing unit 4. 101 is arranged. The separation unit 101 rotates to the separation phase by a driving unit such as a stepping motor (not shown), and the force receiving portion 201 provided on the development frame body 45 is pressed, so that the development unit 4 swings around the pin 50 and the photosensitive member. The drum 1 and the developing roller 40 are separated from each other.

  Further, by rotating the separating means 101 to the release phase, the pressure on the force receiving portion 201 is released, and the photosensitive drum 1 and the developing roller 40 are brought into contact with each other. Here, the toner storage portion 41 is provided with a recess 202 for preventing the operation of the separating means 101. In order to perform a stable separation operation, it is necessary to make the separation means 101 as large as possible in order to reduce the influence of component dimensional tolerances, and the force receiving portion 201 has a rib shape to obtain accuracy.

  Further, the concave portion provided in the developing device frame 45 enables the above-described separating means 101 to be disposed at a position overlapping the process cartridge 7, and has an effect of reducing the size of the image forming apparatus main body 100. Although not shown, the cleaning frame 61 is also provided with a concave shape for avoiding the operation of the separating means.

  Only when the developing operation is performed, the pressing on the force receiving portion 201 is released, and the developing unit 4 is moved to the developing position. At this time, the force receiving portion is pushed up and released in a state where the force receiving portions 201Y, 201M, 201C, and 201K for all colors of yellow, magenta, cyan, and black are pushed up according to the operating mode (see FIG. 10). The force receiving portions 201Y, 201M, 201C, and 201K for all colors of yellow, magenta, cyan, and black are released (see FIG. 2), and only the three color receiving portions 201Y, 201M, and yellow, magenta, and cyan are used. Three states are selected, where 201C is pushed up (see FIG. 11).

  First, when the image forming apparatus main body 100 of the process cartridge 7 is mounted, as shown in FIG. 9, the cams of all the colors yellow, magenta, cyan, and black are in a separated phase. 7, the force receiving portion 201 provided in the developing unit rides on the separating means 101, and the developing roller 40 is separated from the photosensitive drum 1 by a predetermined gap. This separated state is always maintained when the power is turned off and when development is not performed.

  Accordingly, even when the process cartridge 7 is mounted and not used for a long time, the developing roller 40 is always separated from the photosensitive drum 1, so that the developing roller 40 is kept away from the photosensitive drum for a long time. The permanent deformation of the roller layer that occurs by contacting the roller 1 can be reliably prevented.

  As shown in FIGS. 1 and 12, the force receiving portion provided in the developing unit is provided in a substantially central portion in the longitudinal direction of the developing unit 4. Here, the substantially central portion in the longitudinal direction means the substantially central portion in the longitudinal direction of the toner storage portion 41, the longitudinal position of the developing unit 4 corresponding to the substantially central portion in the longitudinal direction of the electrostatic latent image formed on the photosensitive drum 1, It includes a substantially intermediate portion between the rollers 200a and 200b in the axial direction.

  By pressing the substantially central portion in the longitudinal direction of the process cartridge, the separation can be performed in a well-balanced manner, and the container / frame is not twisted. Therefore, a stable separation distance can be obtained with respect to the set separation distance between the photosensitive drum 1 and the developing roller 40, and the separation distance can be made substantially the same at both ends in the longitudinal direction. Further, since a plurality of separation means 101 provided in the image forming apparatus main body 100 is not required in the longitudinal direction of the process cartridge 7, the configuration of the image forming apparatus main body can be simplified.

1 is a perspective view of a process cartridge according to an embodiment of the present invention. 1 is a schematic cross-sectional view (all color separation release state) 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. FIG. 5 is a partial cross-sectional view showing a positioning portion for the process cartridge according to the embodiment of the present invention to the image forming apparatus. 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. 2A and 2B are perspective views showing a relationship between the photosensitive drum and the developing roller according to the embodiment of the present invention, in which FIG. 3A shows a state in which the development separation is released, and FIG. It is sectional drawing which shows the outline of the state of the development separation cancellation | release which concerns on embodiment of this invention. It is sectional drawing which shows the outline of the state of the development separation which concerns on embodiment of this invention. 1 is a schematic cross-sectional view (all color separation state) 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 (three-color separated state) of a color laser printer which is an embodiment of an image forming apparatus using an electrophotographic process. It is a bottom view of the developing device frame concerning an embodiment of the invention.

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 Support hole 50 Support shaft (pin)
55 Memory Unit 56 Communication Unit 60 Cleaning Blade 61 Cleaning Frame 62 Developer Feeding Mechanism 63 Storage Chamber 64 Pressing Spring 65 Dowel 66 Cartridge Pressing Unit 100 Electrophotographic Image Forming Apparatus (Printer)
DESCRIPTION OF SYMBOLS 101 Separation means 102 Guide member 103 Guide rib 104 Cartridge pressing lever 105 Main body positioning part 106 Main body side plate 201 Force receiving part 202 Recessed part A Electrophotographic image forming apparatus main body t Developer

Claims (5)

In a process cartridge that can be attached to and detached from the electrophotographic image forming apparatus main body,
A cleaning unit having a photosensitive drum and a frame for supporting the photosensitive drum;
A developing unit in which a developing roller for developing an electrostatic latent image formed on the photosensitive drum and a developing frame that holds the toner supplied to the developing roller and holds the developing roller are integrated;
A coupling portion that couples the cleaning unit and the developing unit in a swingable manner;
The developing unit has a force receiving portion on the downstream side in the mounting direction in which the process cartridge to which a force is applied from the image forming apparatus main body is mounted on the image forming apparatus main body,
When the force receiving portion is pressed, the force receiving portion moves to swing the developing unit around the coupling portion, thereby separating the photosensitive drum and the developing roller,
The process cartridge according to claim 1, wherein the force receiving portion is provided at a substantially central portion in the longitudinal direction of the developing unit.   2. The process cartridge according to claim 1, wherein the substantially central portion in the longitudinal direction is a substantially central portion in the longitudinal direction of an electrostatic latent image formed on the photosensitive drum.   2. The process cartridge according to claim 1, wherein the developing unit has a toner storage portion for storing toner, and the substantially central portion in the longitudinal direction is substantially the center in the longitudinal direction of the toner storage portion. The developing roller is
An action portion acting on the photosensitive drum;
It consists of a support part that supports the action part at both ends and transmits the drive from the drive source,
A first roller and a second roller that are rotatably engaged with both ends of the support portion, press against the photosensitive drum, and regulate a distance from the developing roller;
2. The process cartridge according to claim 1, wherein the substantially central portion in the longitudinal direction is a substantially intermediate portion in the axial direction of the first roller and the second roller.   2. The process cartridge according to claim 1, wherein the developing unit has a concave portion around the force receiving portion for avoiding an operation of an image forming apparatus main body separating unit that presses the force receiving portion.

Images