JP2006276190A - Process cartridge and electrophotographic image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process cartridge capable of surely holding the separated states of a developing roller and a charging roller from a photoreceptor drum even when vibration is applied at the time of physical distribution or the like, and to provide an electrophotographic image forming apparatus. <P>SOLUTION: In a process cartridge which comprises a photoreceptor unit provided with a photoreceptor drum and a charging roller and a developing unit supported rockably by the photoreceptor unit and turned and provided with a developing roller and can be be attached/detached to/from an electrophotographic image forming apparatus body, when the process cartridge is not used, a separation hook freely turnably provided to the developing unit is engaged with the photoreceptor unit and thereby the charging roller and the developing roller are held at the separated states from the photoreceptor drum. In order to hold the engagement quantity of the separation hook, striking faces for regulating the rocking of the developing unit are formed on the photoreceptor unit and the developing unit respectively. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a process cartridge and an electrophotographic image forming apparatus using the same. In particular, it is suitable for a color electrophotographic image forming apparatus.

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

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

  Conventionally, in an image forming apparatus using an electrophotographic image forming process, the electrophotographic photosensitive member and the process means acting on the electrophotographic photosensitive member are integrally formed into a cartridge, and the cartridge can be attached to and detached from the image forming apparatus main body. The process cartridge method is adopted. According to this process cartridge system, the apparatus can be maintained by the user himself / herself without depending on the service person, so that the operability can be remarkably improved. For this reason, this process cartridge system is widely used in electrophotographic image forming apparatuses.

  There is an in-line type color electrophotographic image forming apparatus in which a plurality of process cartridges are arranged in a line. As a developing means of such a cartridge, there is a contact development method in which development is performed with the developing roller in contact with the electrophotographic photosensitive drum, and the developing roller and the photosensitive drum during image formation maintain a predetermined contact pressure. Therefore, the developing roller is biased with respect to the photosensitive drum.

  In the case of this method, when the developing roller is not used for a long time in contact with the photosensitive drum, the elastic layer of the developing roller may be permanently deformed. May occur.

  As a configuration for solving this problem, a process cartridge and an image forming apparatus provided with a mechanism for separating the photosensitive drum and the developing roller when an image forming operation is not performed have been proposed (for example, (See Patent Document 1 and Patent Document 2).

  On the other hand, as a method for performing charging processing on the surface of a photosensitive drum of a process cartridge that forms an image by electrophotography, a contact charging device that performs charging processing by bringing a charging roller into contact with the surface of the photosensitive drum is widely used. .

  On the other hand, as a means for charging the photosensitive drum, a configuration in which the charging roller is in contact with the photosensitive drum is widely used. However, in the case of the contact charging device, it is necessary to install the charging roller in contact with the surface of the photosensitive drum. Further, it is in pressure contact with the surface of the photosensitive drum with a predetermined pressing pressure. Therefore, if the state of not being used for a long time in that state continues, the elastic layer of the charging roller may be permanently deformed, and this may cause density unevenness of the charging roller cycle in the image.

  In order to prevent such a problem, a latent image is used so that the elastic layer of the charging roller is selectively made of a material that is not easily permanently deformed, or density unevenness of the charging roller period due to the deformation of the elastic layer does not appear in the image. Settings had to be made and there were design constraints.

  Therefore, a method has been proposed in which a member for separating the charging roller and the photosensitive drum is sandwiched when the process cartridge is shipped, and the user removes the sandwiching member during use (see, for example, Patent Document 3).

  Alternatively, there has been proposed a process cartridge or the like provided with a mechanism in which a charging roller that has been separated until then is provided by mounting the process cartridge on the main body of the image forming apparatus (see, for example, Patent Document 4 and Patent Document 5). ).

  There has also been proposed a process cartridge and an image forming apparatus in which the developing roller and the charging roller are held in the same unit and separated from each other by using a stopper or a separation member when the process cartridge is not used (for example, Patent Document 6). reference).

Japanese Patent No. 2974530 (page 2-3, FIG. 1 to FIG. 2) JP 2001-337511 A (page 5-6, FIG. 2) JP 05-188667 A Japanese Patent Laid-Open No. 06-273987 Japanese Patent Laid-Open No. 02-181328 JP 2002-006722 A

  The above prior art sufficiently satisfies the performance desired at that time. However, in recent years, further improvement in performance has been demanded.

  The present invention is a further development of the above-described prior art, and its intended process is to ensure that the developing roller and the charging roller are separated from the photosensitive drum even when vibration is applied during distribution or the like. It is an object of the present invention to provide a process cartridge and an electrophotographic image forming apparatus that can be held.

  Another object of the present invention is to provide a process cartridge and an electrophotographic image forming apparatus that can easily release the separated state of the developing roller and the charging roller without bothering the user.

In order to achieve the above object, an invention according to claim 1 is detachable from an electrophotographic image forming apparatus main body, and includes at least an electrophotographic photosensitive drum, and a charging member for charging the electrophotographic photosensitive drum. A developing member for developing an electrostatic latent image formed on the electrophotographic photosensitive drum, a first unit having the electrophotographic electrophotographic photosensitive drum and the charging member, and swinging to the first unit A second unit that is freely supported and has the developing member, and a pressing force that applies a pressing force between the first unit and the second unit so as to press the developing member against the electrophotographic photosensitive drum. And a process in which the electrophotographic photosensitive drum and the developing member are separated from each other by swinging the second unit against the pressing force of the member and the pressing member. In cartridges,
A separation member for holding the separation state, the separation member being rotatably provided in the second unit, and having a separation member for holding the separation state by engaging one end thereof with the first unit; The first unit and the second unit have contact surfaces that regulate the swing of the developing unit in the direction away from the photosensitive drum in order to maintain the engaged state of the separating member. Each is provided.

  According to a second aspect of the invention, in the first aspect of the invention, the spacing member is an elastic member.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the first abutting surface provided in the first unit rotatably supports the electrophotographic photosensitive drum and the separation member is A bearing member provided on a cleaning frame that engages one end, and a second contact surface provided on the second unit rotatably supports the developing member and rotatably supports the separation member. It is provided in.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the contact surfaces provided on the separation member, the first unit, and the second unit are on both sides in the longitudinal direction. It is characterized by being arranged respectively.

  According to a fifth aspect of the present invention, in the first aspect of the invention, the second unit is provided with an elastic member that abuts against a side surface in the rotational direction of the separation member in order to restrict the rotational movement of the separation member. It is characterized by.

  A sixth aspect of the present invention is the invention according to any one of the first to fifth aspects, wherein the spacing member includes the elastic member and a wall surface provided on a side facing the urging direction of the elastic member. It is characterized by being held between.

The invention according to claim 7 is an electrophotographic image forming apparatus in which a process cartridge is detachable and forms an image on a recording medium.
A conveying means for conveying a recording medium, a mounting portion for detachably mounting the process cartridge according to any one of claims 1 to 6, and a means for moving the developing member away from the electrophotographic photosensitive drum And a separating means.

  According to the first aspect of the present invention, the developing member has the developing member due to an impact or the like at the time of physical distribution, and the engagement of the separating member is maintained by regulating the swing amount of the second unit with respect to the first frame unit. The separation member can be prevented from coming off.

  According to a second aspect of the present invention, when the respective contact surfaces provided on the first unit and the second unit are in contact with each other, the spacing member is engaged with the first unit. Even if a predetermined amount is held, the developing member is included, and the separation member bends when the image forming apparatus main body is mounted, so that it can be easily removed.

  According to the third aspect of the present invention, the engagement amount of the separation member can be held with higher accuracy by providing the contact surfaces on the cleaning frame body and the bearing member on which the separation member acts.

  According to a fourth aspect of the present invention, there is provided at least one of the developing members, even if the distance between the contact surfaces changes due to twisting or bending of the first unit and the second unit. The amount of engagement of the spacing member is reliably maintained.

  According to the fifth aspect of the present invention, it is possible to prevent the separation member from coming off by urging the separation member so as not to easily move in the rotational direction by having the developing member due to an impact at the time of physical distribution or the like. can do.

  According to invention of Claim 6, it has the said developing member, and when energizing a spacing member, it can make it difficult to remove a spacing member by pinching | interposing with the opposite side wall surface of a biasing direction.

  According to the seventh aspect of the present invention, it is possible to provide an electrophotographic image forming apparatus having a process cartridge in which the separation member is not removed due to an impact during physical distribution.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings and embodiments. However, the dimensions, 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, the longitudinal direction of the process cartridge is a direction intersecting with a direction in which the process cartridge is attached to and detached from the apparatus main body (a direction substantially perpendicular to the developing roller rotation axis). And the longitudinal direction of the electrophotographic photosensitive drum. In addition, the upper surface of the process cartridge is a surface located above when the process cartridge is mounted on the apparatus main body, and the lower surface is a surface located below.

  Further, regarding the electrophotographic image forming apparatus, left and right are left or right as viewed from the mounting opening of the process cartridge mounting portion. In the electrophotographic image forming apparatus of the embodiment, the right side is the driving side and the left side is the non-driving side. The numerical symbol of the right member is distinguished by attaching the “R” sub symbol, and the numerical symbol of the left member is appended with the “L” sub symbol.

<Embodiment 1>
(Overall configuration of color electrophotographic image forming apparatus)
First, the overall configuration of the electrophotographic image forming apparatus according to the present embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view of a color electrophotographic image forming apparatus according to this embodiment.

  An electrophotographic image forming apparatus (hereinafter referred to as “image forming apparatus main body” or “apparatus main body”) A shown in FIG. 1 has four process cartridge mounting portions 100 (100a to 100d) arranged in parallel in the vertical direction. . Each of the process cartridges (hereinafter referred to as “cartridges”) 7 (7a to 7d) mounted on the mounting portion 100 has one electrophotographic photosensitive drum (hereinafter referred to as “photosensitive drum”). 1 (1a-1d).

  The photosensitive drum 1 is rotationally driven counterclockwise (FIG. 1) by a driving force of a motor (not shown). Around the photosensitive drum 1, the following components are arranged in order according to the rotation direction.

  More specifically, a charging unit 2 (2a to 2d) for uniformly charging the surface of the photosensitive drum 1 and a scanner unit 3 for irradiating a laser beam based on image information to form an electrostatic latent image on the photosensitive drum 1. (3a to 3d), a developing unit 4 (4a to 4d) as a second frame for developing the electrostatic latent image using a developer, and a developer image formed on the photosensitive drum 1 as a recording medium S. An electrostatic transfer means 5 for transferring the toner and a cleaning means 6 (6a to 6d) for removing the developer remaining on the surface of the photosensitive drum 1 after the transfer are disposed. Here, the photosensitive drum 1, the charging unit 2, the developing unit 4, the cleaning unit 6, and the like are integrally formed as a cartridge to constitute a process cartridge 7 described later.

  The photosensitive drum 1 has an organic photoconductive layer (OPC photosensitive member) coated on the outer peripheral surface of an aluminum cylinder. Both ends of the photosensitive drum 1 are rotatably supported by support members. A driving force from a driving motor (not shown) is transmitted to one end. As a result, the photosensitive drum 1 is driven to rotate counterclockwise.

  The charging unit 2 is a conductive roller formed in a roller shape, and this roller is brought into contact with the surface of the photosensitive drum 1. A charging bias voltage is applied to the roller from the apparatus main body A. Thereby, the surface of the photosensitive drum 1 is uniformly charged.

  The scanner unit 3 is disposed in a substantially horizontal direction with respect to the photosensitive drum 1. Then, image light corresponding to an image signal is irradiated to a polygon mirror 9 (9a to 9d) rotated by a scanner motor (not shown) by a laser diode (not shown). 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 to 10d). Thereby, an electrostatic latent image corresponding to the image signal is formed.

  As shown in FIG. 2, the developing units 4 (4 a to 4 d) include developer containers 41 (41 a to 41 d) that store developers of respective colors (yellow, magenta, cyan, and black), and developing frames. 45.

  The developer is sent to the developer supply roller 43 by the developer transport mechanism 42 in the developer container 41. The developer is applied to the outer periphery of the developing roller 40 by the developing blade 44 pressed against the outer periphery of the developer supplying roller 43 and the developing roller 40 (40a to 40d), and an electric charge is applied to the developer. Further, the developing roller 40 is disposed so as to face the photosensitive drum 1. FIG. 2 shows a developing position, and the developing roller 40 contacts the photosensitive drum 1 with a predetermined pressing force at the developing position.

  Then, a developing bias is applied to the developing roller 40 from the apparatus main body A. As a result, the electrostatic latent image formed on the photosensitive drum 1 is developed by the developer.

  On the other hand, the image forming apparatus main body A has a transfer belt 11 that faces all the photosensitive drums 1 (1a to 1d) and circulates so as to be in contact with the photosensitive drum 1. Then, the recording medium S is conveyed to the transfer position by the transfer belt 11, and the developer image on the photosensitive drum 1 is transferred.

  The transfer roller 12 (12a to 12d) is in contact with the inside of the transfer belt 11. The transfer roller 12 is juxtaposed at a position facing the four photosensitive drums 1. A positive charge is applied from the transfer roller 12 to the recording medium S via the transfer belt 11. As a result, the developer image on the photosensitive drum 1 is transferred to the recording medium S. The transfer belt 11 is stretched around four rollers of a driving roller 13, driven rollers 14a and 14b, and a tension roller 15, and rotates (in the direction of arrow r1). As a result, the transfer belt 11 circulates and the developer image is transferred while the recording medium S is conveyed from the driven roller 14a side to the driving roller 13 side.

  The feeding unit 16 feeds and transports the recording medium S to the image forming unit. A plurality of recording media S are stored in the feeding cassette 17. At the time of image formation, the feeding roller 18 and the registration roller pair 19 rotate according to the image forming operation. Thus, the recording medium S in the cassette 17 is separated and fed one by one. Then, the leading edge of the recording medium S hits the registration roller pair 19 and stops temporarily. Thereafter, the recording medium S is fed to the transfer belt 11 by the registration roller pair 19.

  The fixing unit 20 fixes the developer images of a plurality of colors transferred to the recording medium S. The fixing roller pair 21 includes a rotating heating roller 21a and a pressure roller 21b that presses against the recording medium S and applies heat and pressure to the recording medium S. The recording medium S to which the toner image on the photosensitive drum 1 is transferred is conveyed by the fixing roller pair 21 when passing through the fixing unit 20. Then, heat and pressure are applied by the fixing roller pair 21. As a result, the toner images of a plurality of colors are fixed on the surface of the recording medium S.

  The image forming operation is as follows.

  First, the cartridges 7 (7a to 7d) are sequentially driven in accordance with the image formation timing. Then, the photosensitive drum 1 (1a to 1d) is rotationally driven in accordance with the drive. Then, the scanner units 3 corresponding to the respective cartridges 7 are sequentially driven. By this driving, the charging unit 2 applies a uniform charge to the peripheral surface of the photosensitive drum 1. Then, the unit 3 exposes the circumferential surface of the photosensitive drum 1 according to the image signal to form an electrostatic latent image on the photosensitive drum 1. The developing roller 40 develops the electrostatic latent image.

  As described above, on the recording medium S, the developer images on the photosensitive drums 1 are sequentially transferred by an electric field formed between the photosensitive drums 1 and the transfer rollers 12. The recording medium S on which the four color developer images have been transferred is separated from the transfer belt 11 by the curvature of the driving roller 13. Then, the recording medium S is carried into the fixing unit 20. Then, the recording medium S is nipped and conveyed by a fixing nip portion that is a pressure contact portion between the fixing roller 21a and the pressure roller 21b of the fixing portion 20, and the developer image is heat-fixed. Then, the paper is discharged from the discharge unit 24 to the outside of the apparatus main body by the discharge roller pair 23.

FIG. 1 shows a state in which the developing roller 40 of each cartridge 4 is in contact with the photosensitive drum 1.
(Process cartridge)
Next, the process cartridge according to the present embodiment will be described with reference to FIGS. FIG. 2 is a cross-sectional view of the process cartridge according to the present embodiment, and FIG. 3 is an exploded perspective view of the process cartridge.

  The cartridge 7a containing the yellow developer, the cartridge 7b containing the magenta developer, the cartridge 7c containing the cyan developer, and the cartridge 7d containing the black developer have the same configuration. .

  The cartridge 7 combines a photosensitive unit 50 as a first frame having a photosensitive drum 1, a charging unit 2 and a cleaning unit 6, and a developing unit 4 as a second frame having a developing roller 40. Are integrated.

  The photoconductor unit 50 rotatably supports the photoconductor drum 1 on the cleaning frame 51 via bearings 31 (31R and 31L: FIG. 4). Around the photosensitive drum 1, the above-described charging unit 2 and the cleaning blade 6 of the cleaning unit 6 are arranged.

  Further, the residual developer removed from the surface of the photosensitive drum 1 by the cleaning blade 6 is sent to a removed developer chamber 51 a provided behind the cleaning frame 51 by the developer feeding mechanism 52. Then, by transmitting a driving force of a driving motor (not shown) to the photosensitive unit 50, the photosensitive drum 1 rotates according to the image forming operation.

  The charging means 2 is for charging the surface of the photosensitive drum 1, and in this embodiment, a so-called contact charging method as shown in Japanese Patent Laid-Open No. 63-149669 is used.

  That is, the charging roller 2 is rotatably provided on the cleaning frame 51 by the sliding bearing 61 (FIG. 4). This charging roller 2 is provided with an elastic rubber layer such as EPDM or NBR on a metal roller shaft 2a (for example, a conductive metal core such as iron or SUS), and further provided with a urethane rubber layer in which carbon is dispersed on the week surface. Or a metal roller shaft covered with a foamed urethane rubber layer in which carbon is dispersed. The roller shaft 2a of the charging roller 2 is attached so as to be slidable in the direction of the photosensitive drum 1 along a guide provided inside the frame body 51 via the sliding bearing 61.

  The charging roller 2 is urged in the direction of the photosensitive drum 1 by a pressure spring 64 (FIGS. 5 and 6) that is contracted between the bearing 61 that supports the roller shaft 2a and the frame body. The photosensitive drum 1 is in pressure contact with the surface of the photosensitive drum 1, and is driven to rotate with respect to the photosensitive drum 1. At least one of the bearings 61 is formed of a conductive member, and the surface of the photosensitive drum 1 is uniformly charged by applying a predetermined charging bias to the charging roller 2.

  The developing unit 4 includes a developing roller 40 that contacts the photosensitive drum 1 and rotates in the direction of the arrow r2, a developer container 41 that stores the developer, and a developing frame 45. As shown in FIG. 3, the developing roller 40 is rotatably supported by the developing frame body 45 via drive-side and non-drive-side bearing members 47 and 48. A developer supply roller 43 and a developing blade 44 are disposed on the circumference of the developing roller 40, respectively.

  Further, in the developer container 41, a transport mechanism 42 for stirring the stored developer and transporting it to the developer supply roller 43 is provided. Further, spacer members 72 for restricting the pressure contact amount of the developing roller 40 to the photosensitive drum 1 by restricting the outer diameter of the developing roller 40 to the photosensitive drum 1 by bringing the outer diameter thereof into contact with the photosensitive drum 1 are provided at both ends of the developing roller 40. Each is arranged.

  The developing unit 4 is coupled to the photoconductor unit 50 so as to be swingable with respect to the photoconductor unit 50. That is, the developing unit 4 has shafts 49a attached to the swinging center holes 49 of the photosensitive unit 50 in the rotation center holes 47a and 48a of the bearing members 47 and 48 attached to both ends of the developing device frame 45, respectively. It is coupled to the photoreceptor unit 50 so as to be fitted and swingable. The developing unit 4 is caused by a rotational moment generated around the shaft 49a by the elastic force of a pressure spring (compression coil spring) 54 and a pressure spring 53 (tensile springs: FIGS. 12 to 14) which are elastic members. The developing roller 40 is always urged in the direction in which the developing roller 40 comes into contact with the photosensitive drum 1.

In the contact development method in which development is performed by contacting the photosensitive drum 1 and the developing roller 40, it is preferable that the photosensitive drum 1 is a rigid body and the developing roller 40 is a roller having an elastic body. As this elastic body, a solid rubber single layer or a solid rubber layer coated with a resin coating in consideration of charge imparting property to the developer is used.
(Separation configuration when the process cartridge is not used)
Next, a separation structure between the photosensitive drum, the developing roller, and the charging roller when the process cartridge is not used will be described with reference to FIGS.

  4 to 6 are explanatory views for explaining the charging roller separation mechanism, FIGS. 7A and 8A are partial perspective views for explaining the separation state of the process cartridge when not in use, FIGS. 8-b is a partial perspective view illustrating a state in which the separation of the process cartridge is released.

  5 and 6 are diagrams illustrating the separation mechanism of the charging roller 2 on the non-driving side, but the driving side has almost the same configuration.

  First, as shown in FIG. 4, a link 58 is coupled to the charging roller 2 at a portion of the roller shaft 2 a between both ends of the rubber portion 2 b and the bearing 61. A crank 57 provided inside the cleaning frame 51 is coupled to the other end of the link 58.

  As shown in FIGS. 5 and 6, the crank 57 is coupled to the developing unit swinging central shaft 49 so as to be rotatable about a shaft 59 provided on the side opposite to the photosensitive drum 1. And two arms 57a and 57b extending radially from the center of rotation. The angle formed by both arms is substantially perpendicular, and the tip of the first arm 57 a is coupled to the link 58. The second arm 57b has a projection-shaped actuating portion 65 that faces downward. When the actuating portion 65 is pushed up in the direction of the arrow C, the link 58 moves in the direction of the arrow D, so that both ends of the charging roller 2 are moved. By pulling, the contact pressure of the charging roller 2 with respect to the photosensitive drum 1 decreases, and eventually becomes separated.

  On the other hand, the bearing members 47 and 48 of the developing unit 4 are each provided with a projection-shaped action portion 55 at a position facing the action portion 65. In the state where the developing roller 40 is in contact with the photosensitive drum 1, a predetermined gap W is provided between the actuated portion 65 and the actuating portion 55.

  Further, as shown in FIGS. 7 and 8, the bearing members 47 and 48 of the developing unit 4 are provided with separation hooks 66 for separating the developing roller 40 and the charging roller 2 from the photosensitive drum 1. It is attached so as to be rotatable around 66a. At the tip of the separation hook 66, there are a convex portion 66b that acts to release the separation state when the image forming apparatus main body A is mounted, and a concave portion 66c that engages with the photoreceptor unit 50 to maintain the separation state when the process cartridge 7 is not used. Is provided. The cleaning frame 51 of the photoconductor unit 50 is provided with protrusions 67 and 68 that engage with the recess 66c of the separation hook 66, respectively.

Here, when the process cartridge 7 is not used (new), the process cartridge 7 is shipped with the recess 66c of the separation hook 66 engaged with the projections 67 and 68 as shown in FIGS. 7A and 8A. At this time, as shown in FIG. 6, the developing roller 40 is separated from the photosensitive drum 1 by a predetermined gap L. At the same time, when the developing unit 4 is swung, the working portions of the bearing members 47 and 48 are operated. Since 55 pushes up the actuated portion 65, the charging roller 2 is also separated from the photosensitive drum 1 by a predetermined gap M.
When the developing unit 40 is further swung against the pressing force of the pressure spring 54 in the direction in which the developing roller 40 is further away from the photosensitive drum 1 (in the direction of arrow E in FIG. 6) from that state, the separation hook The amount of engagement between the recess 66c of the 66 and the projections 67 and 68 is reduced, and it becomes easy to come off. Therefore, in the configuration of the present invention, in order to maintain the engagement amount of the separation hook 66, the developing roller 40 of the developing unit 4 swings in the direction away from the photosensitive drum 1 on the cleaning frame 51 and the bearing members 47 and 48. The contact surfaces 51b, 47b, and 48b that restrict the amount of movement are provided.

  With the above configuration, when the process cartridge 7 is not used (the separation hook 66 is engaged with the protrusions 67 and 68) and is shipped from the factory, and a physical impact is applied to the process cartridge 7 during the distribution process. Since the abutment surface 51b of the cleaning frame 51 and the abutment surfaces 47b and 48b of the bearing members 47 and 48 are in contact with each other, the developing unit 4 does not swing more than necessary. The total amount is maintained, and the separation hook 66 does not come off due to physical impact. Accordingly, since the separated state of the developing roller 40 and the charging roller 2 is maintained, the elastic layers of the developing roller 40 and the charging roller 2 can be reliably prevented from being deformed.

  In this embodiment, the contact surface for regulating the swinging amount of the developing unit 4 is provided with a cleaning frame 51 to which the separation hook 66 engages and a bearing member to which the separation hook 66 is rotatably attached. 47 and 48, respectively. The place where the contact surface is provided is not limited to this. For example, the contact surface can be provided on the developer container 41, but each of the cleaning frame body 51 and the bearing members 47 and 48 on which the separation hook 66 directly acts is provided. By providing the abutment surface, it is possible to minimize variations in component deflection, dimensional tolerances, and the like, so that the engagement amount of the separation hook 66 can be held with higher accuracy.

In this embodiment, the separation hooks 66 are provided on the side surfaces on both sides in the longitudinal direction. However, the separation hooks 66 may be provided only on one side. However, when the photoconductor unit 50 frame and the developing unit 4 are twisted or bent, it is also conceivable that the distance between the contact surfaces 51b and 47b, 48b may change. Accordingly, when the separation hooks 66 are provided on both sides in the longitudinal direction, the engagement amount of at least one of the separation hooks 66 can be maintained, so that the separation state of the developing roller 40 and the charging roller 2 can be more reliably maintained.
(Separation release configuration when the image forming apparatus main body is mounted)
Next, with reference to FIGS. 9 to 17, the process cartridge mounting configuration and the separation releasing mechanism of the image forming apparatus main body according to the present embodiment will be described.

  FIG. 9 is an explanatory diagram of a process cartridge mounting configuration in the apparatus main body according to the present embodiment, and FIGS. 10 and 11 are partial detailed views illustrating the process cartridge mounting configuration of the apparatus main body. In FIG. 9, the cartridge 7 is omitted and only the photosensitive drum 1 and the bearings 31 (31R, 31L) are shown for easy understanding of the process cartridge mounting configuration. 12 to 14 are explanatory views for explaining the structure of the separation releasing mechanism when the process cartridge is mounted on the apparatus main body. FIGS. 15 and 16 are image forming apparatuses in the state where the process cartridge is mounted on the apparatus main body. Sectional drawing of a main body and a process cartridge, FIG. 17 is detailed explanatory drawing explaining the bending at the time of releasing engagement of a separation hook. FIGS. 12 to 14 are diagrams for explaining the non-drive-side separation releasing mechanism, but the drive side has almost the same configuration.

  First, the process cartridge 7 is mounted on the apparatus main body A by inserting bearings 31 (31R, 31L) for supporting the photosensitive drum 1 along the guide grooves 34a to 34h (see FIG. 9, arrow). The direction of Y is the mounting direction of the process cartridge 7). Then, as shown in FIG. 10, the position of the process cartridge 7 relative to the apparatus main body A is determined by pressing the bearing 31 against the abutting surfaces 37 and 38 of the guide groove 34.

  The method for pressing the process cartridge 7 in the apparatus main body A is as follows.

  That is, as shown in FIG. 11, the shaft 39 is crimped to the side plate 32. A torsion coil spring 30 is supported on the shaft 39. The end 30 a is fitted and fixed in the hole 32 a of the side plate 32. In the state where the cartridge 7 is not mounted, the spring 30 is restricted in the rotational direction by the bending and raising 32b. When the process cartridge 7 is inserted, the torsion coil spring 30 rotates counterclockwise in the counterclockwise direction. And when the bearing 31 is overcome, the bearing 31 is elastically pressed.

  Next, a configuration for mounting the process cartridge 7 to the apparatus main body A will be described.

  When the process cartridge 7 is mounted on the apparatus main body A, each process cartridge 7 is in a direction intersecting the axial direction of the photosensitive drum 1 with respect to the cartridge mounting portion 100 (100a to 100d: FIG. 1) of the apparatus main body A (substantially). (Mounting direction is indicated by arrow Y in the figure).

  On the right side plate 32R and the left side plate 32L of the apparatus main body A, a pair of mounting guide portions 70 (70R, 70L) for guiding the cartridge 7 to the mounting position in the mounting portion 100 are arranged in parallel, four pairs at equal intervals. Is provided. In addition, the developing unit 4 is attached to one end side and the other end side (left and right side) of the apparatus main body A in a direction that intersects the insertion direction (substantially orthogonal direction) on the back side in the insertion direction of the cartridge 7. Separating means 8 for separating the developing roller 40 from the photosensitive drum 1 against the force 8 A resin cam member (hereinafter referred to as “separating cam” or “cam”) 8 (8R, 8L) is disposed. Yes. The separation cam 80 is configured to be coupled in the same shape and phase at both ends in the longitudinal direction with respect to one rotation shaft 8g.

The cam surface of the cam 8 has a small diameter portion 8e having the smallest radius and a large diameter portion 8f having the largest radius. The small-diameter portion 8e does not contact a force receiving portion 46 (46R / 46L: FIGS. 12 to 14) of the process cartridge 7 to be described later in a state where the developing roller 40 is in contact with the photosensitive drum 1. The shape is a predetermined gap. The large-diameter portion 8f is in contact with the engaging portion 46 so that the developing roller 40 and the photosensitive drum 1 can be separated by a predetermined gap X (FIG. 14). The small-diameter portion 8e and the large-diameter portion 8f are formed with smooth curved surfaces so that the developing roller 40 can be smoothly separated from the photosensitive drum 1.
Separating means 8 cams 8 (8a to 8d) are provided for the yellow, magenta, cyan, and black color cartridges 7, respectively, and they are branched from one stepping motor (not shown) by gear connection. Each is controlled to rotate in synchronization. The cam 8 is controlled so that the developing roller 40 is always separated from the photosensitive drum 1 except during the image forming operation. When the process cartridge is mounted, the cam 8 is in a position where the large diameter portion 8f faces upward. Yes.

  The bearing members 47 and 48 of the developing unit 4 are integrally provided with force receiving portions 46 (46R and 46L) for the cam 8 to come into contact with when the developing roller 40 is separated from the photosensitive drum 1. It has been.

  The process cartridge 7 is in a state in which the separation hook 66 is engaged with the protrusion 68 when the apparatus main body A is not attached, that is, the development roller 40 and the charging roller 2 are both separated from the photosensitive drum 1 (FIG. 12). ing.

  On the other hand, in the apparatus main body A, a projection (not shown) 71 that acts on the projection 66 b and releases the engagement with the projection 68 of the separation hook 66 is provided in the middle of the insertion guide 70 from the side plate 32. It is provided so as to protrude inward. Then, in the process of inserting the process cartridge 7 from the state of FIG. 12 into the apparatus main body A in the direction of the arrow Y, the tip protrusion 66b of the separation hook 66 comes into contact with the protrusion 71 of the apparatus main body 100. The separation hook 66 rotates in the direction of the middle arrow N (FIG. 13). As a result, the engagement of the separation hook 66 with the protrusion 67 of the recess 66c is released, and the developing unit 4 can swing with respect to the photosensitive unit 50, and both the developing roller 40 and the charging roller 2 are pressurized. It is brought into contact with the photosensitive drum 1 by the pressing force of the spring.

  After that, when the process cartridge 7 is further inserted in the arrow Y direction, as shown in FIG. 14, a restricting portion 56 for restricting the upward movement of the photoreceptor unit 50 provided in the photoreceptor unit 50 is provided. Locked by locking portions 90 provided on both side plates of the image forming apparatus main body A, the developing unit 4 is in a state in which the force receiving portion 46 rides on the large-diameter portion 8f of the cam 8 which is a separating means. 40 is separated from the photosensitive drum 1 to complete the mounting of the process cartridge 7 (FIGS. 15 and 16).

  When the apparatus main body A operates to form an image, the cam 8 rotates to release the developing roller 40 and the process cartridge 7 forms an image.

  As described above, in the state where the apparatus main body A is not mounted, the process cartridge 7 is separated from the photosensitive drum 1 with the developing roller 40 and the charging roller 2 by the separation hook 66 engaging with the protrusion 68. Since the engagement of the separation hook 66 is automatically released during insertion into the apparatus main body A, the separation can be easily released without bothering the user. Can do.

  The spacing hook 66 described in the present embodiment is made of an elastic resin. As described above, the contact surfaces of the photoconductor unit 50 frame and the developing unit 4 are in contact with each other, so that the engagement of the separation hook 66 is maintained in a predetermined amount. Therefore, when the process cartridge 7 has the developing member and is attached to the apparatus main body A, the tip protrusion 66b of the separation hook 66 gets over the protrusion 68 of the apparatus main body 100 of the cleaning frame 51 and engages. Although it is necessary to release, since the separation hook 66 of the present invention can elastically bend the tip protrusion 66b as shown in FIG. 17, the separation hook 66 can be easily removed.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIGS. 18 is an exploded perspective view of the process cartridge according to the present embodiment, and FIG.

  In the first embodiment, the cleaning frame 51 and the bearing members 47 and 48 are provided with the contact surfaces 51b and the contact surfaces 47b and 48b, respectively, and the developing hook is further engaged with the separation hook 66 engaged with the protrusion 67. 4, when the developing roller 40 is swung away from the photosensitive drum 1, the abutment surface is brought into contact with each other to regulate the amount of rocking of the developing unit 4 at the time of physical impact and the engagement of the separation hook 66. The configuration for holding the quantity has been described. In the present embodiment, an elastic member is provided on the side surface in the rotational direction of the separation hook 66 so that the separation hook 66 does not easily rotate in the separation release direction due to physical impact.

  Specifically, as shown in FIG. 18, first, on the shaft 48c of the bearing member 48, as in the first embodiment, the separation hook 66 is rotatable about the rotation shaft 66a in the Z direction in the figure. It is attached. A leaf spring 74 is provided between the bearing member 48 and the separation hook 66 as an elastic member that contacts the side surface 66d of the separation hook 66. The leaf spring 74 is urged by a predetermined pressing force from the side surface in the rotational direction of the separation hook 66, so that the separation hook 66 is urged toward the longitudinal outer side of the process cartridge 7.

  Further, the developing unit 4 has a bearing member 75 which is electrically connected to an electrical contact (not shown) provided in the apparatus main body A and includes a contact for applying a voltage to the developing roller 40 and the developing blade 44. The cover 48 is attached to the outer side in the longitudinal direction of the member 48, and a wall surface 75 a is provided on the side facing the biasing direction of the leaf spring 74. When the process cartridge 7 is not used, that is, when the separation hook 66 is engaged with the protrusion 68, the separation hook 66 is moved between the plate spring 74 and the wall surface 75a by the urging force of the plate spring 74 as shown in FIG. It is pinched.

  Here, in the present embodiment, only the configuration on the non-driving side of the process cartridge 7 has been described, but the driving side has the same configuration.

  In the above configuration, since the separation hook 66 is held between the leaf spring 74 and the wall surface 75a, the movement of the separation hook 66 in the rotational direction is restricted. Even when an impact is applied, the separation hook 66 does not easily come off. Accordingly, since the separated state of the developing roller 40 and the charging roller 2 is maintained, the elastic layers of the developing roller 40 and the charging roller 2 can be reliably prevented from being deformed.

  Furthermore, the configuration in which the elastic member is provided on the side surface in the rotational direction of the separation hook 66 according to the present embodiment is a configuration in which a contact surface for restricting the swing amount of the developing unit 4 described in the first embodiment is provided. More effective when combined. In this case, the movement of the separation hook 66 in the rotational direction is also restricted at the same time as the swing amount of the developing unit 4 is restricted to maintain the engagement amount of the separation hook 66. Therefore, the separation hook 66 can be further prevented from coming off at the time of physical impact, and deformation of the elastic layers of the roller 40 and the charging roller 2 can be prevented more reliably.

  In the present embodiment, the separation hook 66 is urged by the leaf spring 74 with a predetermined pressing force, and the urging direction is a direction perpendicular to the rotation direction of the separation hook 66, and The force required for releasing the engagement of the separation hook 66 is biased with a sufficiently weak pressing force, and the process cartridge 7 has the developing member and is attached to the apparatus main body A. There is almost no influence on the separation releasing operation, and therefore the separation can be easily released without impairing the user operability.

<Embodiment 3>
Next, Embodiment 3 of the present invention will be described with reference to FIG. 20 and FIG. FIG. 20 is a perspective view of a separation hook according to the third embodiment, and FIG.

  In the second embodiment described above, the configuration in which the leaf spring 74 urges the separation hook 66 from the side surface in the rotation direction with a predetermined pressing force to restrict the movement of the separation hook 66 in the rotation direction has been described. In the third embodiment, the elastic hook 66d is integrally provided on the separation hook 66.

  Specifically, as shown in FIG. 20, an elastic claw 66e that abuts the bearing member 48 is integrally provided on a side surface 66d on the inner side in the longitudinal direction of the separation hook 66. As shown in FIG. 21, the elastic claw 66e contacts the convex surface 48d of the bearing member 48 with a predetermined pressing force when assembled to the process cartridge 7. Therefore, the separation hook 66 is urged in the longitudinally outward direction by the reaction force.

  As in the second embodiment, a cover member 75 is attached to the outside of the bearing member 48 in the longitudinal direction, and the cover member 75 is on the side facing the direction in which the separation hook 66 is urged. Is provided with a wall surface 75a. When the process cartridge 7 is not used, that is, when the separation hook 66 is engaged with the protrusion 68, the separation hook 66 is urged against the wall surface 75a by the reaction force of the elastic claw 66e.

  Here, in the present embodiment, only the configuration on the non-driving side of the process cartridge 7 has been described, but the driving side has the same configuration.

  In the above configuration, since the separation hook 66 is urged against the wall surface 75a by the reaction force of the elastic claw 66e, the movement of the separation hook 66 in the rotational direction is restricted. Even when a physical distribution impact is applied, the separation hook 66 does not easily come off. Accordingly, since the separated state of the developing roller 40 and the charging roller 2 is maintained, the elastic layers of the developing roller 40 and the charging roller 2 can be reliably prevented from being deformed.

  Further, the configuration in which the elastic hook 66e is provided in the separation hook 66 of the present embodiment is combined with the configuration in which the contact surface for regulating the swing amount of the developing unit 4 described in the first embodiment is provided. More effective. In this case, the movement of the separation hook 66 in the rotational direction is also restricted at the same time as the swing amount of the developing unit 4 is restricted to maintain the engagement amount of the separation hook 66. Therefore, the separation hook 66 can be further prevented from coming off at the time of physical impact, and deformation of the elastic layers of the roller 40 and the charging roller 2 can be prevented more reliably.

  In this embodiment, the separation hook 66 is urged by a predetermined pressing force by the elastic claw 66e provided on the separation hook 66, and the urging direction thereof is perpendicular to the rotation direction of the separation hook 66. The force required when releasing the engagement of the separation hook 66 is biased with a sufficiently weak pressing force. Accordingly, since the separation release operation when the process cartridge 7 has the developing member and is mounted on the apparatus main body A is hardly affected, the separation can be easily released without impairing the user operability.

1 is an overall configuration diagram of a color electrophotographic image forming apparatus according to an embodiment of the present invention. It is sectional drawing of the process cartridge which concerns on embodiment of this invention. 1 is a perspective view of a process cartridge according to an embodiment of the present invention. FIG. 6 is an explanatory diagram for explaining a separation mechanism for separating the charging roller from the photosensitive drum. FIG. 6 is a cross-sectional view illustrating a separation mechanism for separating the charging roller from the photosensitive drum. FIG. 6 is a cross-sectional view illustrating a separation mechanism for separating the charging roller from the photosensitive drum. It is a fragmentary perspective view explaining the state which the separation hook engaged. It is a fragmentary perspective view explaining the state by which engagement of the separation hook was cancelled | released. It is a fragmentary perspective view explaining the state which the separation hook engaged. It is a fragmentary perspective view explaining the state by which engagement of the separation hook was cancelled | released. It is explanatory drawing of the process cartridge mounting structure in the apparatus main body which concerns on this invention. It is a partial detail drawing explaining the process cartridge mounting configuration of the apparatus main body. It is a partial detail drawing explaining the process cartridge mounting configuration of the apparatus main body. FIG. 5 is an explanatory diagram illustrating a configuration of a separation release mechanism when a process cartridge is mounted on the apparatus main body. FIG. 5 is an explanatory diagram illustrating a configuration of a separation release mechanism when a process cartridge is mounted on the apparatus main body. FIG. 5 is an explanatory diagram illustrating a configuration of a separation release mechanism when a process cartridge is mounted on the apparatus main body. FIG. 3 is a cross-sectional view of the apparatus main body with the process cartridge mounted on the apparatus main body. FIG. 3 is a cross-sectional view of the process cartridge in a state where the process cartridge is mounted on the apparatus main body. It is detail explanatory drawing explaining the bending at the time of releasing engagement of a spacing hook. It is a disassembled perspective view of the process cartridge of Embodiment 2 of this invention. FIG. 6 is a configuration explanatory diagram of a process cartridge according to a second embodiment of the present invention. It is a perspective view of the separation hook of Embodiment 3 of the present invention. It is a structure explanatory drawing of the process cartridge of Embodiment 3 of this invention.

Explanation of symbols

A Image forming apparatus S Recording medium 1 (1a to 1d) Electrophotographic photosensitive drum 2 (2a to 2d) Charging means 3 (3a to 3d) Scanner unit 4 (4a to 4d) Development unit (second unit)
5 Electrostatic transfer means 6 (6a-6d) Cleaning means 7 (7a-7d) Process cartridge 8 Separation means 9 (9a-9d) Polygon mirror 10 (10a-10d) Imaging lens 11 Electrostatic transfer belt 12a-12d Transfer Roller 20 Fixing part 30 Torsion coil spring 30a End part 31 (31a, 31b) Bearing 32 Side plate 32a Hole 32b Bending 33 Protruding part 34 (a-h) Guide groove 35 (a-h) Opening hole 36 Compression spring 37, 38 Protrusion Abutting surface 39 Axis 40 (40a to 40d) Developing roller (developing member)
41 Developer container 43 Toner supply roller 45 Development frame body 46 (46R, 46L) Force receiving portion 47, 48 Bearing member 47a, 48a Rotation center hole 47b, 48b Contact surface 48c Shaft 48d Convex surface 49 Development unit swing center (hole) )
49a Development unit swing center (axis)
50 Photosensitive unit (first unit)
51 Cleaning frame 51b Abutting surface 53 Pressure spring (tensile spring) (elastic member)
54 Pressure spring (compression coil spring) (elastic member)
55 Action part 56 (56R, 56L) Restriction part 57 Crank 58 Link 59 Crank rotation shaft 61 Sliding bearing 64 Pressure spring 65 Actuated part 66 (66R, 66L) Separation hook 66a Rotation shaft 66b Convex part 66c Concave part 66d Side surface 66e Elastic claws 67, 68 Protruding part 69 Rib 70 Insertion guide 71 Main body projecting part 72 Spacer member 74 Leaf spring 75 Cover member 75a Wall surface 80 Separating means (cam)
80a-80c Cam action part 80e Small diameter part 80f Large diameter part 90 Locking part 100a-100d Mounting part

Claims (7)

An electrophotographic image forming apparatus main body that is attachable to and detachable from at least an electrophotographic photosensitive drum, a charging member for charging the electrophotographic photosensitive drum, and an electrostatic latent image formed on the electrophotographic photosensitive drum A first unit having the developing member for developing the electrophotographic electrophotographic photosensitive drum and the charging member, a second unit swingably supported by the first unit and having the developing member, A pressing member that applies a pressing force between the first unit and the second unit so as to press the developing member against the electrophotographic photosensitive drum, and the first member against the pressing force of the pressing member. In a process cartridge having a configuration in which the electrophotographic photosensitive drum and the developing member are separated by swinging two units,
A separation member for holding the separation state, the separation member being rotatably provided in the second unit, and having a separation member for holding the separation state by engaging one end thereof with the first unit; The first unit and the second unit have contact surfaces that regulate the swing of the developing unit in the direction away from the photosensitive drum in order to maintain the engaged state of the separating member. Each process cartridge is provided.   2. The process cartridge according to claim 1, wherein the spacing member is an elastic member.   A first contact surface provided in the first unit is provided in a cleaning frame body that rotatably supports the electrophotographic photosensitive drum and engages one end of the separation member, and is provided in the second unit. 3. The process according to claim 1, wherein the second contact surface is provided on a bearing member that rotatably supports the developing member and that rotatably rotates the separating member. cartridge.   The process according to any one of claims 1 to 3, wherein the contact surfaces provided on each of the separation member, the first unit, and the second unit are respectively disposed on both sides in the longitudinal direction. cartridge.   2. The process cartridge according to claim 1, wherein the second unit is provided with an elastic member that abuts against a side surface in the rotation direction of the spacing member in order to restrict the rotational movement of the spacing member.   The process according to claim 1, wherein the separation member is sandwiched between the elastic member and a wall surface provided on a side facing the urging direction of the elastic member. cartridge. In an electrophotographic image forming apparatus in which a process cartridge is detachable and forms an image on a recording medium.
A conveying means for conveying a recording medium, a mounting portion for detachably mounting the process cartridge according to any one of claims 1 to 6, and a means for moving the developing member away from the electrophotographic photosensitive drum An electrophotographic image forming apparatus comprising: a separating unit;

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