JP4366371B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic image forming apparatus for forming an image on a recording medium, to which a process cartridge can be attached and detached, and to an electrophotographic image forming apparatus that can be transported with the process cartridge mounted.

  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.

  Conventionally, in an electrophotographic image forming apparatus using an electrophotographic image forming process, the electrophotographic photosensitive member and the process means acting on the electrophotographic photosensitive member are integrated into a unit, and this unit is attached to and detached from the image forming apparatus main body. The method that enables it is adopted.

  As the developing means of the process cartridge, there is a contact development system in which development is performed while a developing roller is in contact with an electrophotographic photosensitive drum. In this contact development method, the developing roller is biased to the photosensitive drum. Therefore, with the process cartridge mounted on the image forming apparatus main body, the photosensitive drum is always pressed by the developing roller even if it is not used for a long time.

  Therefore, when the image forming apparatus main body is not used for a long time, the developing roller is separated from the photosensitive drum, and the toner is developed by bringing the developing roller into contact with the photosensitive drum only when forming an image. It has been proposed (Patent Document 1).

  Further, as a physical distribution form of the image forming apparatus main body and the unit, conventionally, the image forming apparatus main body and the unit are packed in separate boxes, or the image forming apparatus main body and the unit are packed in one box. It has been. The unit is mounted on the image forming apparatus main body during use and is positioned at an image formable position. Among them, for the purpose of reducing the volume of the box when packing the main body of the image forming apparatus and the unit in one box and increasing the distribution efficiency, it is proposed to pack the unit in the state where it is mounted in the main body of the image forming apparatus. ing. For example, an image forming apparatus having first mounting means for mounting and holding the unit at an image formable position and second mounting means for mounting and holding the unit at a position different from the image forming position is described. (See Patent Document 2).

JP 2001-318506 A JP-A-7-104637

  Conventionally, when a unit is packed and transported in a state where it is mounted on the main body of the image forming apparatus, a drive transmission portion from the main body to the unit or a contact portion between a photosensitive drum as an electrophotographic photosensitive member and a transfer roller is transported. Measures against vibrations and shocks were desired.

  SUMMARY OF THE INVENTION An object of the present invention is to transport an electrophotographic photosensitive drum from a developing roller or other member contacting the electrophotographic photosensitive drum when the electrophotographic image forming apparatus is transported in a state where a process cartridge is mounted in the main body of the electrophotographic image forming apparatus. An electrophotographic image forming apparatus that can be protected is provided.

  Another object of the present invention is to provide an electrophotographic image forming apparatus capable of performing separation and contact switching between an electrophotographic photosensitive drum, a developing roller, and other members during image formation with a small driving source. It is.

A typical means in the present invention for solving the above-described problem is an electrophotographic image forming apparatus for forming an image on a recording medium, to which a process cartridge can be attached and detached, and can be transported with the process cartridge mounted. In the electrophotographic image forming apparatus, (1) a first position and a second position retracted from the first position are provided on a cam shaft that receives a driving force from a motor provided in a main body of the image forming apparatus. a first cam member that can be taken, the first cam member provided on one end and the other end in the longitudinal direction of said process cartridge, respectively provided on (2) the first cam member, A second position that can take a third position protruding from the outer shape of the first cam member and a fourth position retracted from the third position and accommodated inside the outer shape of the first cam member . cam And wood, (3) a mounting member for mounting detachably said process cartridge, (4) the a said process cartridge mounted to the mounting member, an electrophotographic photosensitive drum, said electrophotographic photosensitive member A developing roller for developing an electrostatic latent image formed on the drum, a first frame for supporting the electrophotographic photosensitive drum, and a second frame for supporting the developing roller, the first frame A second frame body movably coupled to the frame body, and a first force receiving portion provided on one end side and the other end side in the longitudinal direction of the process cartridge, wherein the process cartridge is the main body is attached to, when the first cam member is positioned in the first position, by contacting with the first cam member, to separate the said developing roller and said electrophotographic photosensitive drum Receiving a force from said first cam member, when the first cam member is positioned in the second position, the first force receiving portion for spacing said first cam member, the longitudinal of said process cartridge A second force receiving portion provided on one end side and the other end side in the direction when the process cartridge is mounted on the main body and the second cam member is located at the third position, By contacting the second cam member , the electrophotographic photosensitive drum and the developing roller are separated from each other, and further, a force for separating the first cam member and the first force receiving portion from the first cam member is applied . has a second force receiving portion for receiving the second cam member, said process cartridge having a, when transporting the process cartridge in a state of being mounted on said body, said second cam member, each first In the third position The second cam provided on the one end side and the other end side by moving the first cam member when the image forming operation is started after the process cartridge is mounted on the main body. The members abut on the main body at different timings and move from the third position to the fourth position to release the force separating the electrophotographic photosensitive drum from the developing roller. Features.

In the present invention, when the process cartridge is mounted and transported in the electrophotographic image forming apparatus, the second cam member is brought into contact with the second force receiving portion of the process cartridge so that the developing roller is moved from the electrophotographic photosensitive drum. The first cam member and the first force receiving portion can be separated from each other. When the image is formed, the load on the drive source can be reduced by changing the movement timing of the second cam member at both ends in the longitudinal direction of the process cartridge. Therefore, the electrophotographic photosensitive drum and the developing roller can be separated and contacted by a small drive source.

[First Embodiment]
Next, a process cartridge and an electrophotographic image forming apparatus to which the process cartridge can be attached and detached according to an embodiment of the present invention will be described with reference to the drawings.

  In this embodiment, an electrophotographic image forming apparatus (hereinafter simply referred to as “image forming apparatus”) that forms an image on an electrophotographic photosensitive member using an electrophotographic image forming process, and is detachably attached to the electrophotographic image forming apparatus. A process cartridge (hereinafter simply referred to as “cartridge”) is illustrated.

  In the following description, the longitudinal direction of the cartridge is a direction (substantially orthogonal direction) intersecting with a direction in which the cartridge is attached to and detached from the electrophotographic image forming apparatus main body (hereinafter simply referred to as “main body”). It intersects (substantially orthogonal) with the transport direction.

(Overall configuration of image forming apparatus)
First, the overall configuration of the image forming apparatus will be described together with the image forming operation with reference to FIG. FIG. 1 is a schematic view showing a state in which a cartridge to which this embodiment can be applied is mounted on an image forming apparatus.

  As shown in FIG. 1, the image forming apparatus according to the present embodiment includes a mounting member 70 (70Ra, 70Ra, 70) for detachably mounting four cartridges 7 (7a, 7b, 7c, 7d) arranged in parallel in the vertical direction. 70Rb, 70Rc, 70Rd). Then, an image forming unit is formed which forms toner images of yellow, magenta, cyan, and black in order from the bottom. Each image forming unit has the same configuration although the color of the formed toner image is different. Therefore, in the following, when there is no particular need to distinguish, subscripts a, b, c, and d attached to the drawings are omitted to indicate that they are elements provided for any color, and a general description will be given. To do.

  In each image forming unit, a laser image based on image information is irradiated from the optical system 3 to form a toner image on the electrophotographic photosensitive drum 1 which is a drum-shaped electrophotographic photosensitive member. In synchronization with the toner image formation, the recording medium S such as recording paper or OHP sheet is conveyed from the cassette 17 by a conveying means including a separation feeding roller 18, a conveying roller 19, a conveying belt 11, and the like.

  The conveyor belt 11 is a film-like member that circulates and moves so as to face and contact all the electrophotographic photosensitive drums (hereinafter referred to as “photosensitive drums”) 1. The conveyor belt 11 is wound around four rollers, a driving roller 13, driven rollers 14a and 14b, and a tension roller 15, and rotates in the direction of arrow A in FIG. The recording medium S is transported to the transfer position by the transport belt 11. The toner image formed on the photosensitive drum 1 is transferred to the recording medium S by applying a bias to a transfer roller 12 (12a, 12b, 12c, 12d) as a transfer means, and the recording medium S is fixed to the fixing means. It is conveyed to 20. This fixing means 20 has a driving roller 21a and a fixing roller 21b incorporating a heater, and the toner image is fixed by applying heat and pressure to S conveyed through the fixing means 20. The recording medium S is discharged to the discharge unit 24 by the discharge roller pair 23.

  When the cartridge 7 is not attached to the main body 100, the developing roller 25 is always in contact with the photosensitive drum 1 (see FIG. 2). The cartridge 7 is mounted on the main body 100 by inserting a bearing that supports the photosensitive drum 1 along a guide groove (not shown). In the cartridge 7 mounted on the main body 100, the separation operation of the photosensitive drum 1 and the developing roller 25 is performed by the separation members 8R and 8L which are the first engagement members shown in FIG.

(Entire cartridge configuration)
On the other hand, the cartridge 7 of this embodiment is detachable from the main body 100, and includes at least a photosensitive drum, charging means for charging the electrophotographic photosensitive drum, and a latent image formed on the photosensitive drum. And developing means for developing.

  As shown in FIG. 2, the cartridge 7 of the present embodiment rotates the photosensitive drum 1 having a photosensitive layer and uniformly charges the surface thereof by a charging roller 2 as a charging unit. Then, the photosensitive drum 1 is exposed to the optical image from the optical system 3 of the image forming apparatus to form an electrostatic latent image. Next, a uniform toner layer is formed on the developing roller 25 by the developing blade 35 of the developing means. Thereafter, the toner is transferred to the photosensitive drum 1 according to the latent image, thereby forming a toner image corresponding to the latent image and making it visible. Further, after the toner image is transferred to the recording medium S by the transfer roller 12, the toner remaining on the photosensitive drum 1 is removed by the cleaning blade 6 of the cleaning means.

  The cartridge 7 is divided into a photosensitive unit 26 and a developing unit 4 (4a to 4d). The photosensitive unit 26 supports the photosensitive drum 1, the charging roller 2, and the cleaning blade 6. The developing unit 4 supports members constituting developing means such as the developing roller 25.

  The photosensitive drum 1 is rotatably attached to a cleaning frame 27 which is a first frame of the photosensitive unit 26 via a bearing (not shown). As described above, the charging roller 2 and the cleaning blade 6 are in contact with the peripheral surface of the photosensitive drum 1. Further, the residual toner removed from the peripheral surface of the photosensitive drum 1 by the cleaning blade 6 is sent to a removed toner chamber 27 a provided behind the cleaning frame 27 by the toner feeding mechanism 29.

  A charging roller bearing 28 is attached to the cleaning frame 27 so as to be movable in the direction of line D connecting the rotation center of the charging roller 2 and the rotation center of the photosensitive drum 1. The rotating shaft 2j of the charging roller 2 is rotatably attached to the charging roller bearing 28. The charging roller bearing 28 is pressurized toward the photosensitive drum 1 by the charging roller pressing member 46. For this reason, the charging roller 2 is in a state of being pressed against the photosensitive drum 1.

  In the developing unit 4, a developing roller 25 that contacts the photosensitive drum 1 and rotates in the direction of arrow B in FIG. 2 is supported by the second frame. The second frame is composed of a toner container 30 containing toner, a developing frame 31, and side covers 32R and 32L. The developing roller 25 is rotatably supported at both ends (one end side and the other end side) of the developing frame 31 in the longitudinal direction. Further, a toner supply roller 34 that contacts the developing roller 25 and rotates in the direction of arrow C in FIG. 2 and a developing blade 35 that regulates the toner layer on the developing roller 25 are in contact with the peripheral surface of the developing roller 25. is doing. Further, in the toner container 30, a toner transport mechanism 36 for stirring the stored toner and transporting the toner to the toner supply roller 34 is provided.

  The developing unit 4 has a suspended structure in which the entire developing unit 4 is supported so as to swing (rotate) with respect to the photosensitive unit 26. That is, the developing unit 4 is rotatably coupled to the photosensitive unit 26 around the shafts 37R and 37L fitted in the holes 32bR and 32bL provided on the side covers 32R and 32L. .

  When the image of the cartridge 7 is formed, the developing unit 4 is always urged by the pressure spring 38 that is a pressing member so that the developing roller 25 is brought into contact with the photosensitive drum 1 by the rotation moment about the shafts 37R and 37L. Has been.

  The cartridge 7 of the present embodiment can take the first separated state and the second separated state by swinging the developing unit 4 with respect to the photosensitive unit 26. The first separated state is a state in which the developing roller 25 is separated from the photosensitive drum 1. The first separation state is necessary to extend the life of each of the photosensitive drums 1 by separating the developing roller 25 when not involved in image formation.

  The second separated state is a state in which the developing roller 25 and the charging roller 2 are separated from the photosensitive drum 1, and the separation members 8R and 8L and the first force receiving portions 32aR and 32aL described later are separated from each other. . The need for the second separation state is that the cartridge 7 and the main body 100 are damaged or broken by removing the contacted portion when the cartridge 7 is transported while being mounted on the main body 100. This is to prevent it.

  As shown in FIG. 4, the side covers 32R and 32L of the developing unit 4 are provided with second force receiving portions 32cR and 32cL that receive a force from the main body in order to bring the cartridge 7 into the second separated state. . Further, the side covers 32R and 32L are provided with first force receiving portions 32aR and 32aL for receiving a force from the main body in order to bring the cartridge into the first separated state. The first force receiving portions 32aR and 32aL separate from the photosensitive drum 1 developing roller 25 by abutting against the separation members 8R and 8L when the separation members 8R and 8L are located at the first position. The force is received from the separating members 8R and 8L.

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

(Means for separating the photosensitive drum from the developing member and the charging member)
Next, a separating means for separating the developing roller 25 and the charging roller 2 from the photosensitive drum 1 in the cartridge 7 according to the present embodiment will be described with reference to FIGS.

  As described above, the cartridge 7 of this embodiment takes the second separated state in which the developing roller 25 and the charging roller 2 are separated from the photosensitive drum 1 and the first separated state in which the developing roller 25 is separated from the photosensitive drum 1. Configured to get. In FIG. 4, the separation members 8R and 8L as the first engagement members act on the first force receiving portions 32aR and 32aL to place the cartridge 7 in the first separation state. Further, auxiliary separation members 42R and 42L (see FIG. 3) as second engagement members act on the second force receiving portions 32cR and 32cL to place the cartridge 7 in the second separation state.

  As shown in FIG. 3, the separation members 8 </ b> R and 8 </ b> L are connected to each other by a support shaft 51, and a gear 60 is attached to one end of each support shaft 51. The gears 60a and 60b mesh with the gear 61a, and the gears 60c and 60d mesh with the gear 61b. The gear 61a meshes with the gear 62a, the gear 61b meshes with the gear 62b, and the gears 62a and 62b mesh with the stepping motor 63 that is one drive source.

  In the above configuration, when the drive is transmitted from the stepping motor 63, the separation members 8R and 8L rotate via the gears.

  In FIG. 5, in order to separate the developing roller 25 from the photosensitive drum 1, two eccentric cam-shaped separating members 8R and 8L (first cam member) are integrally formed by a separating member drive shaft 43 (cam shaft). The main body is rotatably provided. The separation members 8R and 8L can take the first position shown in FIG. 6 and the second position retracted from the first position shown in FIG. The first position is a position for separating the electrophotographic photosensitive drum and the developing roller, and the second position is a position for contacting the electrophotographic photosensitive drum and the developing roller. It is.

  Auxiliary separation members 42R and 42L as second engagement members for separating the charging roller 2 from the photosensitive drum 1 are rotatably attached to the separation members 8R and 8L.

  The auxiliary spacing members 42R and 42L (second cam members) rotate to project from the third position protruding outward from the maximum outer shape of the spacing members 8R and 8L and the maximum outer shape of the spacing members 8R and 8L. It is comprised so that the 4th position which is a state which cannot be taken can be taken. That is, in the fourth position, the auxiliary separation members 42R and 42L are fixed to positions inside the maximum outer shape of the separation members 8R and 8L and retracted from the third position.

  Further, as shown in FIG. 5, the auxiliary separation member 42R is provided so as to be rotatable about the shaft 42aR by inserting a shaft 42aR integral with the auxiliary separation member 42R into a mounting hole provided in the separation member 8R. Yes. Further, the auxiliary separating member 42R is locked to the rotation restricting portion 8hR provided on the separating member 8R, so that the auxiliary separating member 42R does not rotate in the clockwise direction in FIG. Further, the auxiliary separating member 42R is provided with an elastically deformable locking portion 42bR that is hooked on a claw-shaped protrusion 8dR formed on the separating member 8R.

  The spacing member 8L and the auxiliary spacing member 42L on the opposite side in the longitudinal direction of the spacing member drive shaft 43 are similarly attached.

(Separation operation of developing roller and charging roller)
In FIG. 6, the spacing members 8R and 8L rotate in the direction of arrow E around the drive shaft 43, whereby the positions of the first force receiving portions 32aR and 32aL provided on the side covers 32R and 32L of the developing unit 4 change. . Since the developing unit 4 swings about the shaft 37R (37L) that is the center of swinging, the developing roller 25 comes in contact with and separates from the photosensitive drum 1 as shown in FIG.

  The positional relationship of the separation structure will be described in more detail. As shown in FIG. 4B, the first force receiving portion 32aR is at a position facing the separation member 8R. Further, the second force receiving portion 32cR is at a position facing the auxiliary separation member 42R. Thus, the second force receiving portion 32cR and the first force receiving portion 32aR are arranged at positions shifted in the longitudinal direction of the drive shaft 43. That is, the first force receiving portion 32aR and the second force receiving portion 32cR are provided on protrusions protruding in the longitudinal direction from the side cover 32R. The second force receiving portion 32cL and the first force receiving portion 32aL on the opposite side in the longitudinal direction of the cartridge 7 are similarly arranged at positions shifted in the longitudinal direction.

  Next, the separation of the charging roller 2 will be described. As shown in FIG. 5, the second force receiving portions 32cR and 32cL of the developing unit 4 are in contact with the auxiliary separating members 42R and 42L in a state where the second force receiving portions 32cR and 32cL are in the third position protruding outward from the maximum outer shape of the separating members 8R and 8L. Touch. At this time, the photosensitive drum 1 and the developing roller 25 are separated from each other, and the second force receiving portions 32cR and 32cL further apply a force to separate the separating members 8R and 8L and the first force receiving portions 32aR and 32aL from the auxiliary separating member 42R. , Received from 42L. Therefore, only the developing roller 25 is further separated from the state separated from the photosensitive drum 1, and the charging roller 2 is also separated from the photosensitive drum 1.

  When the auxiliary separation members 42R and 42L are in the third position, the separation members 8R and 8L are separated from the first force receiving portions 32aR and 32aL. Therefore, even if the cartridge 7 is transported in a state where it is mounted on the main body 100 in this state, the separation members 8R and 8L and the first force receiving portions 32aR and 32aL are not damaged or damaged by an impact or the like. . The auxiliary separation members 42R and 42L are in contact with the second force receiving portions 32cR and 32cL. However, the auxiliary separating members 42R and 42L and the second force receiving portions 32cR and 32cL are used only when the cartridge 7 is transported with the main body 100 attached thereto, so there is no problem.

  More specifically, as shown in FIG. 5, the operating member 40R is exposed to light in a state where the shaft 27bR provided integrally with the cleaning frame 27 of the photosensitive unit 26 is inserted into the hole 40aR of the operating member 40R. It is attached to the body unit 26. The actuating member 40R is rotatable about the shaft 27bR.

  The shaft 39aR provided integrally with the charging roller separation member 39R is rotatably attached to the separation member attachment hole 40bR provided in the operating member 40R. The shaft 2j of the charging roller 2 is inserted and mounted in the charging roller mounting hole 39bR provided in the charging roller separation member 39R.

  5 to 7, only one end side in the longitudinal direction of the cartridge 7 is shown, but a similar operation member, a charging roller separation member, and the like are attached to the other end side.

  In FIG. 5, the auxiliary separation member 42R provided on the separation member 8R is in contact with the second force receiving portion 32cR provided on the side cover 32R of the developing unit 4. In this state, the developing unit 4 rotates with respect to the photosensitive unit 26 about the shaft 37R passing through the hole 32bR. The urging portion 32dR provided integrally with the side cover 32R of the developing unit 4 pushes up the operating member 40R as a separating member engaged with the charging roller separating member 39R. As a result, the operating member 40R rotates in the arrow J direction around the shaft 27bR. As a result, the charging roller separating member 39R is pulled in the arrow G direction, and the charging roller 2 is separated from the photosensitive drum 1.

  As described above, when the auxiliary separation member 42R pushes up the second force receiving portion 32cR and the charging roller 2 is separated from the photosensitive drum 1, the separation amount of the developing unit 4 (first oscillation amount) is the first of the separation member 8R. This is larger than the swing amount (second swing amount) when the developing roller 25 is separated from the photosensitive drum 1 by pushing up the first force receiving portion 32aR. Therefore, when the charging roller 2 is separated from the photosensitive drum 1, the developing roller 25 is also separated from the photosensitive drum 1 (second separated state).

  In the shipping state of the main body 100, the cartridge 7 is transported while being attached to the main body 100 and maintaining the second separated state in which the charging roller 2 and the developing roller 25 shown in FIG. Is done. Thus, the packaging material and the packing space can be reduced by transporting (bundling) the cartridge 7 with the cartridge 7 mounted on the main body 100 and shipping it. Even if the storage period before shipment is long, not only the developing roller 25 but also the charging roller 2 is not pressed against the photosensitive drum 1, so that these rollers are not deformed. Further, as described above, the separation members 8R and 8L and the first force receiving portions 32aR and 32aL are not damaged or damaged by an impact or the like.

  Then, the motor that operates the separation member is driven from the time when the main power supply 100 is first turned on (initial time) to the time when the first printing is started, and the separation member 8R rotates around the drive shaft 43 in the direction of arrow E in FIG. . When the separating member 8R rotates in the direction of arrow E, the auxiliary separating member 42R contacts the regulating member 50R disposed in the main body 100, rotates about the shaft 42aR in the direction of arrow F, and contacts the second force receiving portion 32cR. The engagement is released.

  As shown in FIG. 6, the auxiliary separation member 42R is housed in a region inside the outer shape 8g of the separation member 8R. At this time, the locking portion 42bR provided on the auxiliary separation member 42 is lightly fitted (snap hook) with the protrusion 8dR of the separation member 8R and fixed in a posture in which it is housed in a region inside the outer shape 8g of the separation member 8R. Is done.

  As a result, the developing unit 4 rotates about the shaft 37R passing through the hole 32bR with respect to the photoreceptor unit 26, and the first force receiving portion 32aR provided on the side cover 32R contacts the outer shape 8g of the separating member 8R. It will be in contact.

  At that time, the urging portion 32dR is separated from the operating member 40R, and the force pulling the charging roller separating member 39R in the direction of arrow G is released. For this reason, the charging roller separating member 39R is pulled in the direction of arrow H by the force of the charging roller pressing member 46 (see FIG. 2) for pressing the charging roller 2 against the photosensitive drum 1. Then, the charging roller 2 comes into contact with the photosensitive drum 1. Therefore, only the developing roller 25 is in the first separated state in which the developing roller 25 is separated from the photosensitive drum 1 inside the main body 100 which has been used.

  Thereafter, the developing roller 25 can be brought into contact with or separated from the photosensitive drum 1 by rotating the separating member 8R.

  After the use of the main body 100 (image formation) is started, the charging roller 2 remains in contact with the photosensitive drum 1, but the developing roller 25 may be separated from the photosensitive drum 1 as necessary. Is possible. That is, when not involved in image formation, the life of the developing roller 25 can be extended by separating the developing roller 25 from the photosensitive drum 1. The amount of rocking (second rocking amount) of the developing unit 4 with respect to the photosensitive unit 26 for separating and contacting the developing roller 25 with respect to the photosensitive drum 1 is that when the charging roller 2 is separated from the photosensitive drum 1. It is smaller than the swing amount (first swing amount). For this reason, the contact and separation of the developing roller 25 with respect to the photosensitive drum 1 are performed smoothly.

  In order to reliably separate the charging roller 2 from the photosensitive drum 1 over the entire length, the operation described above is performed in the same manner for the operation member, the charging roller separation member, and the like provided on the opposite side in the longitudinal direction.

(Image mode and separation member operation)
Next, the operation of the separating members 8R and 8L according to the image mode will be described.

  In the present embodiment, the standby state, the full color state, and the monocolor state can be selected. The standby state is a state in which all the developing rollers 25 and the photosensitive drum 1 are separated from each other by contacting the first force receiving portions 32aR and 32aL with the maximum radii of the separation members 8R and 8L of the four image forming portions. The full-color state is a state in which the separation members 8R and 8L of all the image forming units are separated from the first force receiving portions 32aR and 32aL, and all the developing rollers 25 and the photosensitive drum 1 are in contact with each other. Further, the monocolor state contacts the first force receiving portions 32aR and 32aL corresponding to the maximum radii of the separation members 8Ra, 8La, 8Rb, 8Lb, 8Rc, and 8Lc of the color image forming portion (yellow, cyan, magenta). On the other hand, the separation members 8Rd and 8Ld of the fourth image forming portion (black) are separated from the corresponding first force receiving portions 32aR and 32aLd, so that only the developing roller 25d of the fourth image forming portion is in contact with the photosensitive drum 1. It is in contact.

  As shown in FIG. 3, each of the separating members 8R and 8L of each image forming unit has a cam profile, and the phases of the separating members 8R and 8L of each image forming unit are shifted, so that The state can be switched.

  In the full color mode, each of the standby members 8R and 8L in the standby state rotates counterclockwise (in the direction of the arrow in FIG. 3). As a result, the developing roller 25 contacts the photosensitive drum 1 in the order of the first image forming unit (yellow) → second image forming unit (cyan) → third image forming unit (magenta) → fourth image forming unit (black). Develop and continue touching. After the development operation is completed, the separation members 8R and 8L in the full color state are rotated counterclockwise. Accordingly, the developing roller 25 is separated from the photosensitive drum 1 in the order of the first image forming unit (yellow) → the second image forming unit (cyan) → the third image forming unit (magenta) → the fourth image forming unit (black). I will do it. Then, the recording is finished by setting each of the separation members 8R and 8L to the standby state.

  In the mono-color mode, the separation members 8R and 8L in the standby state are rotated in the opposite direction (clockwise) to the full-color mode. As a result, the developing roller 25d of only the fourth image forming unit (black) is brought into contact with the photosensitive drum 1 to perform the developing operation. After the development operation is completed, the black color developing roller 25d is separated from the photosensitive drum 1d by rotating the separation members 8R and 8L in the monocolor state in the same direction (counterclockwise) as in the full color mode. Then, the recording is finished by setting each of the separation members 8R and 8L to the standby state.

(Driving member drive configuration and operation timing)
Next, a drive configuration for driving the auxiliary separation members 42R and 42L will be described. In the image forming apparatus of the present embodiment, as shown in FIG. 8, the arrangement positions of the regulating members 50R and 50L for operating the auxiliary separating members 42R and 42L are shifted on the left and right of each image forming unit. Yes. Accordingly, it is possible to make a time difference in the storage timing at which the auxiliary separation members 42R and 42L on the left and right of each image forming unit are housed inside the separation members 8R and 8L.

  More specifically, when the stepping motor 63 is driven, the separating members 8R and 8L rotate in the direction of arrow E, and one of the auxiliary separating members 42R comes into contact with the regulating member 50R, and the inside of the outside of the separating member 8R. (See FIG. 9). When the separating members 8R and 8L further rotate in the direction of arrow E, the auxiliary separating member 42L that is not housed contacts the regulating member 50L and is housed in the outer shape of the separating member 8L (see FIG. 10).

  As a result, the load torque is distributed to the motor 63 driving the separation members 8R and 8L as shown in FIG. 11, and the torque can be reduced.

  If the auxiliary separation members 42R and 42L are accommodated, the storage timings (state change timings) of the left and right auxiliary separation members 42R and 42L in all the image forming units may be considered at the same time. However, in that case, as shown in FIG. 12, the motor 63 that drives the separation members 8R and 8L becomes high for a moment (storage timing) when the load torque is present. For this reason, it is necessary to arrange an expensive and large drive motor even at the expense of space and cost, or to arrange a drive motor in each image forming unit.

  On the other hand, in the present embodiment, as described above, the load torque related to the motor is dispersed and reduced by changing the timing of moving the left and right auxiliary separation members 42R, 42L from the third position to the fourth position. ing. For this reason, the contact and separation switching operation between the photosensitive drum 1 of the cartridge and the developing roller 25 can be performed with one small and inexpensive driving source. Further, even if the drive source is small, the auxiliary spacing members 42R and 42L can be accommodated in the outer shape of the spacing members 8R and 8L without the drive source being stepped out, and space saving and cost reduction are possible. .

  In the present embodiment, when the auxiliary separation members 42R and 42L are in the third position, the separation members 8R and 8L and the first force receiving portions 32aR and 32aL are separated from each other. Therefore, even if the cartridge 7 is transported in the state where the main body 100 is mounted in this state, the photosensitive drum 1 and the developing roller 25 can be protected from an impact during transportation, and at the same time, the separating members 8R and 8L and the first member are protected. The force receiving portions 32aR and 32aL can also be protected from impact during transportation.

  Further, the main body 100 is provided with auxiliary separation members 42R and 42L for separating the charging roller 2 from the photosensitive drum 1, and separation members 8R and 8L for separating the developing roller 25 from the photosensitive drum 1. The developing unit 4 of the cartridge 7 is provided with force receiving portions separately at positions facing the respective positions of the separating members 8R and 8L and the auxiliary separating members 42R and 42L. With this configuration, the separation between the charging roller 2 and the developing roller 25 can be independently controlled, and the separating operation of the charging roller 2 and the developing roller 25 from the photosensitive drum 1 can be stably performed. Is possible.

  In addition, when the main body 100 is shipped, the charging roller 2 as well as the developing roller 25 can be separated from the photosensitive drum 1 when the cartridge 7 is mounted and shipped in advance.

  The above-mentioned components are not deformed even when the cartridge is mounted in the main body, shipped, and transported, and the image forming apparatus that realizes a plug-in play that can be used only by the user turning on the main body is complicated. Can be provided without taking a simple configuration.

  In the above-described embodiment, the example in which the left and right auxiliary separation members 42R and 42L are stored at different timings has been described. However, the timing may be different for each image forming unit. For example, as shown in FIGS. 13 and 14, the positions of the regulating members 50R and 50L that contact when the auxiliary separating members 42R and 42L are housed in the outer shape of the separating members 8R and 8L are shown in the first and second images. The forming unit and the third and fourth image forming units are arranged at different positions.

  In this way, the timing at which the auxiliary separation members 42Ra, 42La, 42Rb, 42Lb of the first and second image forming units are accommodated in the outer shape of the separation members 8Ra, 8La, 8Rb, 8Lb, and the third and fourth The auxiliary separation members 42Rc, 42Lc, 42Rd, and 42Ld of the image forming unit are housed in the outer shapes of the separation members 8Rc, 8Lc, 8Rd, and 8Ld. For this reason, even if it is a small and cheap motor, it becomes possible to accommodate the auxiliary | assistant spacing members 42R and 42L in the outer shape of the spacing members 8R and 8L without stepping out.

  In the above example, the operation timings of the first and second image forming units are the same as those of the third and fourth image forming units. However, the auxiliary separation members 42R and 42L are arranged at different timings in each image forming unit. You may make it accommodate in the external shape of the separation members 8R and 8L.

1 is an overall configuration diagram of a color electrophotographic image forming apparatus. It is a cross-sectional explanatory view of the cartridge. It is drive explanatory drawing of a separation member and an auxiliary separation member. It is a relationship explanatory drawing of a separation member, an auxiliary separation member, a 1st force receiving part, and a 2nd force receiving part. It is a figure explaining the contact and separation operation | movement of a developing roller and a charging roller. It is a figure explaining the contact and separation operation | movement of a developing roller and a charging roller. It is a figure explaining the contact and separation operation | movement of a developing roller and a charging roller. It is a structure explanatory view for making the operation timing of the left and right auxiliary separation members different. It is a structure explanatory view for making the operation timing of the left and right auxiliary separation members different. It is a structure explanatory view for making the operation timing of the left and right auxiliary separation members different. It is explanatory drawing of the load torque of a motor when the operation timing of the left and right auxiliary separation members is varied. It is explanatory drawing of the load torque of a motor when the operation timing of the left and right auxiliary separation members is the same. FIG. 10 is a configuration explanatory diagram in the case where the operation timing of the auxiliary separation member is varied for each image forming unit. FIG. 10 is a configuration explanatory diagram in the case where the operation timing of the auxiliary separation member is varied for each image forming unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Photosensitive drum 4 ... Developing unit 7 ... Cartridge 8R, 8L ... Separation member 8dR ... Projection 8g ... External shape 8hR ... Rotation restriction part
25… Developing roller
26… Photoreceptor unit
27… Cleaning frame
31 ... Development frame
32R, 32L ... side cover
32aL ... 1st force receiving part 32aR,
32aR, 32aL ... 1st force receiving part
32bR, 32bL ... hole
32cR, 32cL ... 2nd force receiving part
32dR ... biasing section
37R, 37L ... axis
38… Pressure spring
39R: Charging roller separation member
39aR ... axis
39bR ... Charging roller mounting hole
40R ... Actuating member
40aR ... hole
40bR ... Spacer mounting hole
42R, 42L ... Auxiliary spacing member
42aR ... axis
42bR ... Locking part
43… Separating member drive shaft
46… Charging roller pressure member
50R, 50L ... Regulator
51… Support shaft
60… gear
63… Motor
70… Mounting material
100 ... body

Claims (2)

An electrophotographic image forming apparatus for forming an image on a recording medium, to which a process cartridge can be attached and detached, wherein the electrophotographic image forming apparatus can be transported in a state where the process cartridge is mounted.
(1) A first cam member that is provided on a cam shaft that receives a driving force from a motor provided in a main body of the image forming apparatus and can take a first position and a second position retracted from the first position. A first cam member provided on one end side and the other end side in the longitudinal direction of the process cartridge;
(2) said first respectively provided in the cam member, than the outline of the first third position and the third of said first cam member is retracted from position protruding than the outline of the cam member A second cam member capable of taking a fourth position housed inside ;
(3) a mounting member for detachably mounting the process cartridge;
(4) The process cartridge mounted on the mounting member,
An electrophotographic photosensitive drum;
A developing roller for developing the electrostatic latent image formed on the electrophotographic photosensitive drum;
A first frame for supporting the electrophotographic photosensitive drum;
A second frame for supporting the developing roller, wherein the second frame is movably coupled to the first frame;
A first force receiving portion provided at one end side and the other end side in the longitudinal direction of the process cartridge, wherein the process cartridge is mounted on the main body, and the first cam member is at the first position. when located, by contacting with the first cam member receives a force for separating the said developing roller and said electrophotographic photosensitive drum from said first cam member, said first cam member is the A first force receiving portion spaced apart from the first cam member when positioned at the second position ;
A second force receiving portion provided at one end side and the other end side in the longitudinal direction of the process cartridge, wherein the process cartridge is mounted on the main body, and the second cam member is at the third position. When positioned, by contacting the second cam member , the electrophotographic photosensitive drum and the developing roller are separated from each other, and further, the first cam member and the first force receiving portion are separated from each other. A second force receiving portion that receives a force from the second cam member ;
The process cartridge having:
Have
When the process cartridge is transported in a state of being mounted on the main body, the second cam members are positioned at the third position, and an image forming operation is started after the process cartridge is mounted on the main body. At this time, by moving the first cam member , the second cam members provided on the one end side and the other end side come into contact with the main body at different timings, respectively, and from the third position, An electrophotographic image forming apparatus which moves to a fourth position. The process cartridge is
A charging roller for charging the electrophotographic photosensitive drum;
A separation member for separating the electrophotographic photosensitive drum from the charging roller when the process cartridge is mounted on the main body and the second cam member is located at the third position;
The electrophotographic image forming apparatus according to claim 1, further comprising:

Images