JP2012048025A - Color electrophotographic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive low-end color electrophotographic apparatus adopting a mechanism of switching between monochrome/color outputs with a process unit separated from a transfer belt, and capable of performing a cleaning operation while suppressing enlargement of the apparatus.SOLUTION: A photoreceptor approaching/separating mechanism includes: a photoreceptor approaching/separating lever 80; a link 81 moving the photoreceptor approaching/separating lever 80 in the cross direction of a printer; a gear 82 to which the link 81 is connected; a gear 83 incorporating a one-way clutch; an approach/separation driving motor 84; a gear 85 fixed to an upper cover opening/closing shaft 86; a link 87 moving the link 81 in conjunction with the opening of the upper cover; a gear 88 to which the link 87 is connected; and a gear train connecting them.

Description

  The present invention relates to a color electrophotographic apparatus, and more particularly to a color electrophotographic apparatus provided with a mechanism for switching a monochrome / color output by separating a process unit from a transfer belt.

  Conventional low-end color electrophotographic apparatuses have often used a system in which toner is formed in a uniform and thin layer on the outer peripheral portion of the developing roller by regulation by a regulation blade and an applied voltage. In addition, a cleaning blade has been often used as a method of cleaning a remaining toner image after transferring a toner image formed on a photosensitive member to a transfer member. Here, as a drawback of the regulating blade system of the developing device, as the number of printed sheets increases, a part of the toner becomes coarse, and the coarse toner is caught between the developing roller and the regulating blade, thereby promoting the wear of the developing roller. There has been a problem that streaky image unevenness occurs on the outer peripheral portion of the developing roller due to shortening of the developing roller life, image defect, and non-uniform toner layer.

In addition, when the toner is continuously pressed and rotated between the developing roller and the regulating blade for a long period of time, the toner adheres to the outer peripheral portion of the developing roller, so-called toner filming occurs, and a normal image is generated. There was a problem that could not be maintained.
Further, there is a problem in that the wear of the developing roller is promoted also by the biting of foreign matter existing in the developing device, the life of the developing roller is shortened, the image is lost, and the streaky image unevenness occurs on the outer peripheral portion of the developing roller.
In addition, when the number of printed sheets of the photoconductor cleaning blade increases, foreign matter such as coarse toner or paper dust is caught between the cleaning blade and the photoconductor, and the wear of the photoconductor is promoted to shorten the lifespan, image loss, There have been problems such as the occurrence of streak-like image defects on the outer periphery of the photoreceptor. In particular, in the tandem direct rotation system, paper touches the photoreceptor directly, so foreign substances such as paper dust and dust are likely to be caught, and regular cleaning operations are indispensable.

Also, in a tandem direct rotation type image forming apparatus in which a replaceable process unit in which a developing device and a photoconductor are integrated is arranged on a transfer belt, the transfer belt is a paper conveyance path, and the transfer belt Switching between monochrome / color output by the separation operation is difficult because the device is small at the low end. Therefore, means for separating the process unit from the transfer belt is known.
Further, in a general low-end color electrophotographic apparatus, when the photosensitive member is rotationally driven in a printing operation, a driving force is transmitted from only one side, so that a force that lifts the non-driving side of the photosensitive member works. As a result, image loss occurs when the photosensitive member is separated from the transfer belt, and means for providing an urging member such as a spring for urging the photosensitive member to the transfer belt is already known.
As a conventional technique, Japanese Patent Application Laid-Open No. H10-228561 discloses that the photosensitive member is separated from the transfer belt by the contact / separation mechanism from the state where the photosensitive member is in contact with the transfer belt for the purpose of suppressing wear of the photosensitive member and the conveyance belt and toner deterioration. The configuration is disclosed, and a sensor and its discrimination processing technology are disclosed as control means of the contact / separation mechanism.

However, the conventional mechanism for switching between monochrome / color output by bringing the process unit into contact / separation from the transfer belt moves the position in accordance with the contact / separation operation. It is difficult to introduce such a mechanism due to problems in the size of the apparatus, and when a cleaning operation by reverse rotation driving is adopted, as shown in FIG. 8, a process unit pressing spring 60 provided in the upper cover. If the spring force of is not increased, the process unit will protrude upward when driven in reverse rotation. However, if the spring force is strengthened, after replacing a process unit that has reached the end of its life, a very large force is required to close the upper cover, and some people cannot close it. Therefore, at present, a countermeasure is adopted in which a highly durable cleaning blade or photoconductor is employed. However, there still remains a problem that a foreign toner such as coarse toner or paper dust is caught and toner filming of the developing roller occurs.
The prior art disclosed in Patent Document 1 is similar to the present invention in that the color / monochrome output is switched by bringing the photosensitive member into contact with / separating from the transfer belt. The problems described above, such as biting of foreign matter such as coarse toner and paper dust, and toner filming of the developing roller, cannot be solved.
The present invention has been made in view of such a problem, and employs a mechanism for switching the monochrome / color output by separating the process unit from the transfer belt, and is inexpensive and suppresses the enlargement of the apparatus, thereby performing a cleaning operation. An object of the present invention is to provide a low-end color electrophotographic apparatus that can perform the above.

In order to solve the above-mentioned problems, the present invention provides a plurality of process units having at least an image carrier, a charging unit, and a developing unit and arranged in parallel, and opposed to the image carriers. And transferring means for transferring the toner image formed on each image carrier to a transfer material, and separating at least one of the plurality of process units from a position where the image carrier approaches the transfer means. A color electrophotographic apparatus having contact / separation means for advancing / retreating to / from a position, wherein the contact / separation means is disposed across a plurality of process units and advances / retreats in an arrangement direction of each process unit And a drive unit that drives the image carrier contact / separation lever. The image carrier contact / separation lever presses the image carrier to move from the transfer unit when it moves in the separation direction. Separate A pressure portion, a biasing portion that biases the image carrier in a direction to approach the transfer means when moved in an approaching direction opposite to the separation direction, and holds the image carrier in the approaching position. A separation limiting member.
According to a second aspect of the present invention, the image carrier contact / separation lever moves forward and backward in a direction orthogonal to the axial direction of the image carrier.
According to a third aspect of the present invention, the image carrier includes an image carrier main body and shaft portions protruding from both end portions of the image carrier main body, and the pressing portion is in contact with both end shaft portions of the image carrier. When the image carrier contact / separation lever moves in the separation direction, the image carrier is moved in the separation direction by pressing the both end shaft portions.
According to a fourth aspect of the present invention, the process unit includes four process units corresponding to yellow, cyan, magenta, and black developers, and the contact / separation unit contacts and separates the process units related to the developer other than black. It is configured as described above.

According to a fifth aspect of the present invention, the image carrier can be rotated forward and backward, and only when the image carrier is biased in a direction approaching the transfer unit by the image carrier contact / separation lever. Is reversely rotated.
According to a sixth aspect of the present invention, the transfer means can be rotated in the forward and reverse directions, and the transfer means is reversed only when the image carrier is biased in a direction approaching the transfer means by the image carrier contact / separation lever. It is made to rotate.
According to a seventh aspect of the present invention, the apparatus further includes a casing having a casing main body that accommodates the process units, the transfer unit, and the contacting / separating unit, and a cover that opens and closes the opening of the casing main body. By operating in conjunction with the operation, a mechanism for operating the contacting / separating means is provided, and the interlocking operating mechanism moves the image carrier contacting / separating lever in the separating direction when the cover is opened, The image carrier contact / separation lever is not moved in the approaching direction when the cover is closed.
According to an eighth aspect of the present invention, the interlock operation mechanism includes a cover rotation gear that is fixed to the opening / closing shaft of the cover and rotates in conjunction with the cover opening / closing operation, and a gear mechanism that sequentially transmits the rotational force from the cover rotation gear. And a link mechanism for converting the rotational force from the gear mechanism into a linear motion and moving the image carrier contact / separation lever in the separating direction.

  According to the present invention, in a low-end color electrophotographic apparatus adopting a tandem linear rotation system, a high conveyance speed and a transfer belt do not come in contact with each other, so that a flat conveyance path can be formed, which has been a problem. In addition, it is possible to reduce the life and image loss due to biting of foreign matters such as coarse toner and paper dust of the developing roller and toner filming of the developing roller.

1 is a schematic configuration diagram illustrating a printer according to an embodiment of the present invention. FIG. 4 is an enlarged configuration diagram illustrating a process unit for K of the printer according to the embodiment of the present invention. It is a figure which shows the state which removed the process unit in order to demonstrate a photoreceptor contact-separation mechanism. It is a perspective view which shows a photoreceptor contact state. It is a perspective view which shows a photoreceptor separated state. It is a schematic diagram explaining the operation | movement at the time of opening of an upper cover. 6 is a flowchart for explaining a photoreceptor contact / separation operation. It is a schematic block diagram which shows the printer which concerns on the conventional Example.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. .

FIG. 1 is a schematic configuration diagram illustrating a printer according to an embodiment of the present invention. FIG. 2 is an enlarged configuration diagram showing the K process unit of the printer. FIG. 1 shows the printer from the side, where A is the front of the printer and B is the rear.
The printer 100 includes four process units 1Y, 1M, 1C, and 1K for forming toner images of yellow, magenta, cyan, and black (hereinafter referred to as Y, M, C, and K). These use Y, M, C, and K toners of different colors as the image forming material, but the other configurations are the same and are replaced when the lifetime is reached.
Taking a process unit 1K for forming a K toner image as an example, as shown in FIG. 2, a drum-shaped photosensitive member 2K as an image carrier, a drum cleaning device 3K, a charge eliminating device (not shown), and a charging device 4K. And a developing device 5K as developing means. The process unit 1K, which is an image forming unit, can be attached to and detached from the printer body, so that consumable parts can be replaced at a time.
The charging device 4K uniformly charges the surface of the photoreceptor 2K that is rotated clockwise (arrow) in the drawing by a driving unit (not shown). The surface of the uniformly charged photoconductor 2K is exposed and scanned by the laser beam L to carry an electrostatic latent image for K. The electrostatic latent image for K is developed into a K toner image by a developing device 5K using K toner (not shown).

The drum cleaning device 3K is provided with a cleaning blade 13K that removes transfer residual toner adhering to the surface of the photoreceptor 2K after the transfer process. The static eliminator neutralizes residual charges on the photoreceptor 2K after cleaning. By this charge removal, the surface of the photoreceptor 2K is initialized and prepared for the next image formation.
In the process units (1Y, 1M, 1C) of other colors, (Y, M, C) toner images are similarly formed on the photoreceptors (2Y, 2M, 2C), and are formed on a transfer belt 16 described later. Transferred onto the conveyed paper P.
The developing device 5K includes a vertically long hopper 6K that stores K toner (not shown) and a developing unit 7K. In the hopper 6K, an agitator 8K that is rotationally driven by a driving means (not shown), an agitation paddle 9K that is rotationally driven by a driving means (not shown) vertically below, and a rotational drive that is driven by a driving means (not shown) in the vertical direction thereof. A toner supply roller 10K to be used is disposed. The K toner in the hopper 6K moves toward the toner supply roller 10K by its own weight while being stirred by the rotational drive of the agitator 8K and the stirring paddle 9K. The toner supply roller 10K has a metal cored bar and a roller portion made of foamed resin or the like coated on the surface of the metal core roller 10K, while adhering K toner in the hopper portion 6K to the surface of the roller portion. Rotate.

In the developing unit 7K of the developing device 5K, a developing roller 11K that rotates while contacting the photoreceptor 2K and the toner supply roller 10K, and a thinning blade 12K that contacts the tip of the developing roller 11K are disposed. Yes. The K toner adhered to the toner supply roller 10K in the hopper 6K is supplied to the surface of the development roller 11K at the contact portion between the development roller 11K and the toner supply roller 10K. When the supplied K toner passes through the contact position between the roller and the thinning blade 12K as the developing roller 11K rotates, the layer thickness on the roller surface is regulated.
Then, the K toner after the layer thickness regulation adheres to the electrostatic latent image for K on the surface of the photosensitive member 2K in the developing region which is a contact portion between the developing roller 11K and the photosensitive member 2K. By this adhesion, the electrostatic latent image for K is developed into a K toner image.

Although the process unit for K has been described with reference to FIG. 2, the process units 1Y, 1M, and 1C for Y, M, and C also perform the same process on the surfaces of the photoreceptors 2Y, 2M, and 2C. A C toner image is formed. In FIG. 1 described above, an optical writing unit 70 is disposed above the process units 1Y, 1M, 1C, and 1K in the vertical direction. The optical writing unit 70, which is an optical writing device, optically scans the photoreceptors 2Y, 2M, 2C, and 2K in the process units 1Y, 1M, 1C, and 1K with a laser beam L emitted from a semiconductor laser based on image information. . By this optical scanning, electrostatic latent images for Y, M, C, and K are formed on the photoreceptors 2Y, 2M, 2C, and 2K.
The optical writing unit 70 irradiates a photoconductor through a plurality of optical lenses and mirrors while deflecting a laser beam L emitted from a light source in a main scanning direction by a polygon mirror rotated by a polygon motor. It is.

Below the process units 1Y, 1M, 1C, and 1K, there is disposed a transfer unit 15 that moves the endless transfer belt 16 endlessly in the counterclockwise direction while stretching.
In addition to the transfer belt 16, the transfer unit 15 serving as a transfer means is provided with a driving roller 17, a driven roller 18, four transfer rollers 19Y, 19M, 19C, and 19K, and a cleaning blade as a belt cleaning device 21.
The transfer belt 16 is stretched by a driving roller 17, a driven roller 18, and four transfer rollers 19Y, 19M, 19C, and 19K disposed inside the loop. Then, it is moved endlessly in the same direction by the rotational force of the driving roller 17 that is driven to rotate in the counterclockwise direction in the drawing by a driving means (not shown).

The four transfer rollers 19Y, 19M, 19C, and 19K sandwich the endless transfer belt 16 between the photoreceptors 2Y, 2M, 2C, and 2K. By this sandwiching, transfer nips for Y, M, C, and K where the surface of the transfer belt 16 and the photoreceptors 2Y, 2M, 2C, and 2K abut are formed.
A transfer bias is applied to each of the transfer rollers 19Y, 19M, 19C, and 19K by a transfer bias power source (not shown), whereby the electrostatic latent images of the photoreceptors 2Y, 2M, 2C, and 2K, and the transfer rollers 19Y, A transfer electric field is formed between 19M, 19C, and 19K. Instead of the transfer rollers 19Y, 19M, 19C, and 19K, a transfer charger, a transfer brush, or the like may be employed.

Below the transfer unit 15, a paper feed cassette 30 that stores a plurality of recording sheets P in a bundle of sheets is slidably attached to the printer housing. In the paper feed cassette 30, a paper feed roller 30a is brought into contact with the top recording paper P of the paper bundle, and the recording paper is rotated by rotating it in a counterclockwise direction in the drawing at a predetermined timing. P is sent out toward the paper feed path 31. A registration roller pair 32 is disposed near the end of the paper feed path 31. The registration roller pair 32 stops the rotation of both rollers as soon as the recording paper P delivered from the paper feed cassette 30 is sandwiched between the rollers. Then, rotation driving is resumed at a timing at which the sandwiched recording paper P can be synchronized with the toner image developed on the above-described photosensitive member, and the recording paper P is sent out toward the transfer belt 16.
The recording paper P is conveyed by the transfer belt 16, and the four-color toner images are sequentially transferred to the recording paper P at the above-described transfer nip, and become a full-color toner image combined with the white color of the recording paper P. The recording paper P having the full-color toner image formed on the surface in this way is sent to a fixing device 34 to be described later. The transfer residual toner that has not been transferred to the recording paper P adheres to the transfer belt 16 after passing through the transfer nip. This is cleaned from the belt surface by the belt cleaning device 21 in contact with the surface of the intermediate transfer belt 16.

The fixing device 34 forms a fixing nip by a fixing roller 34a containing a heat source such as a halogen lamp (not shown) and a pressure roller 34b that rotates while contacting the fixing roller 34a with a predetermined pressure. The recording paper P fed into the fixing device 34 is sandwiched between the fixing nips such that the unfixed toner image carrying surface is brought into close contact with the fixing roller 34a. Then, the toner in the toner image is softened by the influence of heating and pressurization, and the full color image is fixed.
The recording paper P discharged from the inside of the fixing device 34 passes through the paper discharge path 36 and is discharged to the outside by the paper discharge roller pair 37 and is stacked on the stack portion which is the upper surface of the upper cover 50 of the housing. . The upper cover 50 can be opened and closed to allow the process units 1Y, 1M, 1C, and 1K to be replaced.

FIG. 3 is a diagram showing a state in which the process unit is removed in order to explain the photoreceptor contact / separation mechanism. The photosensitive member contacting / separating mechanism (contacting / separating means) includes a photosensitive member contacting / separating lever 80 (image carrier contacting / separating lever) that is arranged across a plurality of process units and advances and retreats in the arrangement direction of each process unit. The contact / separation lever 80 moves in the approaching direction opposite to the separation direction, and a pressing portion that presses the photosensitive member (image carrier) 2 to move away from the transfer roller 19 (transfer means) when moved in the separation direction. Sometimes the photosensitive member abutting position 89 (biasing portion (recess)) for urging the photosensitive member 2 in the direction of approaching the transfer roller 19 and the photosensitive member shaft pressing portion 91 for holding the photosensitive member 2 at the approaching position. (Separation limiting member).
That is, the photoreceptor contact / separation mechanism includes a photoreceptor contact / separation lever 80, a link 81 for moving the photoreceptor contact / separation lever 80 in the front-rear direction of the printer, a gear 82 to which the link 81 is connected, and a gear with a built-in one-way clutch. 83, a contact / separation drive motor (drive means) 84, a gear 85 fixed to the upper cover opening / closing shaft 86, a link 87 for moving the link 81 in accordance with the opening of the upper cover, a gear 88 to which the link 87 is connected, and a gear for connecting them. It consists of columns.

  FIG. 4 is a perspective view showing the photosensitive member contact state. The gear train is driven by the contact / separation drive motor 84, the gear 82 is rotated by a half turn, the rotational motion is changed to the motion in the forward direction of the apparatus by the link 81, and the photoreceptor contact / separation lever 80 is pushed forward in the printer. The photoreceptor contact position 89 of the photoreceptor contact / separation lever 80 is moved to the position of the photoreceptor shafts 22Y, 22M, and 22C of the photoreceptors 2Y, 2M, and 2C, and the photoreceptors 2Y, 2M, and 2C are brought into contact with the transfer belt 16. Let At this time, the link 87 does not transmit drive to the gear 88 by the slit portion. With this operation, the photosensitive member shaft pressing portion 91 located above the contact position 89 of the photosensitive member contact / separation lever 80 is prevented from floating. As a result, the urging members of the process units 1Y, 1M, and 1C become unnecessary, and between the photosensitive members 2Y, 2M, 2C, and 2K and the cleaning blades 13Y, 13M, 13C, and 13K and the developing rollers 11Y, 11M, and It becomes possible to perform the cleaning operation between 11C and 11K and the regulating blades 12Y, 12M, 12C and 12K. Further, the transfer belt 16 also performs the reverse rotation operation of the same amount during the reverse rotation driving, thereby preventing the photoconductor and the transfer belt from being damaged by rubbing, and the cleaning operation between the cleaning blade as the belt cleaning device 21 and the transfer belt. It is possible to serve as both. Note that the shape of the photoconductor shaft pressing portion 91 is not limited as long as it can limit the separation of the photoconductors 1Y, 1M, 1C, and 1K from the transfer belt 16.

  FIG. 5 is a perspective view showing a photosensitive member separation state. As in the case of contact with the photosensitive member, the gear train is driven by the contact / separation drive motor 84, the gear 82 is rotated by a half circumference, and the rotational movement is changed to the backward movement of the apparatus by the link 81. Is pulled to the rear side of the printer, and the photosensitive member separation position 90 of the photosensitive member contact / separation lever 80 is moved to the position of the photosensitive member shafts 22Y, 22M, and 22C of the photosensitive members 2Y, 2M, and 2C. 2C is separated from the transfer belt 16. At this time, the link 87 does not transmit drive to the gear 88 by the slit portion. As a result, conventional color / monochrome switching is possible.

FIG. 6 is a schematic diagram for explaining the operation when the upper cover is opened. The opening cover 50 will be described with reference to FIG. By opening the upper cover 50, the gear 85 fixed to the upper cover opening / closing shaft 86 rotates, and the gear 88 and the gear train connecting the gear 88 rotate. When the photosensitive member is in contact, the gear and the link are in the positional relationship shown in FIG. 6A. However, the gear 88 rotates halfway according to the opening of the upper cover 50, the link 87 is pulled, and the link 81 is also pulled. Thus, the positional relationship shown in FIG. At this time, since the gear 83 has a built-in one-way clutch, the driving force is not transmitted to the motor. Then, the photoreceptor contact / separation lever 80 is pulled in the backward direction of the apparatus, and the photoreceptor separation position 90 of the photoreceptor contact / separation lever 80 is moved to the positions of the photoreceptor shafts 22Y, 22M, and 22C of the photoreceptors 2Y, 2M, and 2C. Then, the photoreceptors 2Y, 2M, and 2C are separated from the transfer belt 16. As a result, even if the photoconductor is in contact, the photoconductors 2Y, 2M, and 2C are separated if the upper cover 50 is opened. Therefore, the process unit 12Y is not obstructed by the photoconductor shaft pressing portion 91. , 12M, 12C, 12K can be exchanged.
When the photoreceptors 2Y, 2M, and 2C are in a separated state, the gear and the link are in the positional relationship shown in FIG. 6B, so that the gear 82 and the link are linked even if the gear 88 is rotated by the slit portion of the link 87. No drive is transmitted to 81. When the upper cover 50 is closed, the gears and the links change from the positional relationship shown in FIG. 6C to the positional relationship shown in FIG. 6B, so that the photoreceptors 2Y, 2M, and 2C remain in the separated state.

FIG. 7 is a flowchart for explaining the photoreceptor contact / separation operation.
When the power is turned on (S1), the current position of the photoreceptor contact / separation lever 80 is determined by a sensor such as a photocoupler (not shown) to determine the contact position, separation position, and other positions (S2). If it is in the position or any other position, the position of the photoreceptor contact / separation lever 80 is moved to the contact position (S9).
When a job is received from a PC (not shown) or the like (S3), it is determined whether the job needs to be switched between color and monochrome (S4). If necessary, a photoreceptor contact / separation switching operation is performed (S10). Only at the time of switching from color to monochrome, the photosensitive member and a driving gear (not shown) for driving the photosensitive member are rotated in the reverse direction to reduce the meshing between the gears. At this time, the photosensitive member and the developing roller rotate reversely to perform a cleaning operation. This is because it has been confirmed that the foreign matter can be prevented from being caught and toner filming can be prevented if the reverse rotation is usually several millimeters to several tens of millimeters in the outer peripheral length. Then, a printing operation is performed (S5).
When the switching from color to monochrome is not performed and the specified number of prints that changes depending on the material of the photoconductor and the developing roller and the contact condition with the blade is exceeded (Yes in S6), the position of the photoconductor contact / separation lever 80 Is moved to the contact position, and a cleaning operation is performed (S11).
If there is an unprinted job, the process returns to S4 to determine whether color / monochrome switching is necessary. If there is no job, the process waits until a new job is received (S8). If a job is received, the process returns to S4 to determine whether color / monochrome switching is necessary.

According to the present invention, in the contact / separation mechanism that performs the contact / separation operation by the photoreceptor contact / separation lever, each of the yellow, magenta, and cyan process units is provided by providing the photoreceptor contact / separation lever with the photoreceptor shaft pressing portion. A spring or the like, which is an urging member that was necessary when making contact with or separated from the transfer means, is not necessary, and the urging force can be reduced.
Also, during printing in the contact state of the photosensitive member, the anti-driving side lift due to the force on the photosensitive member driving side is prevented, and in the cleaning operation in which the photosensitive member and the developing roller are driven to rotate reversely during non-printing. The process unit can be prevented from rising.
Even when the photoconductor contact lever is moved so that the photoconductor is in contact with the transfer means, the photoconductor contact lever returns to the separation position by opening the upper cover of the casing housing the process unit. User1 who can exchange process units that are consumables.

DESCRIPTION OF SYMBOLS 1 Process unit, 2 photoreceptor, 3 drum cleaning apparatus, 4 charging device, 5 developing device, 6 hopper part, 7 developing part, 8 agitator, 9 stirring paddle, 10 toner supply roller, 11 developing roller, 12 thinning blade , 13 Cleaning blade, 15 Transfer unit, 16 Transfer belt, 17 Drive roller, 18 Drive roller, 19 Transfer roller, 21 Belt cleaning device, 22 Photoconductor shaft, 23 Spring, 30 Paper feed cassette, 31 Paper feed path, 32 Resist Roller pair, 34 fixing device, 36 paper discharge path, 37 paper discharge roller pair, 50 upper cover, 70 optical writing unit, 80 photoconductor contact lever, 81 link, 82 gear, 83 gear, 84 contact drive motor, 85 gear, 86 upper cover opening / closing axis, 87 link, 88 gear, 89 Light body striking position, 90 photoconductor separated position, 91 photoconductor shaft holding portion

Japanese Patent Laid-Open No. 11-95521

Claims (8)

A plurality of process units having at least an image carrier, a charging unit, and a developing unit and arranged in parallel, and a toner image formed on each image carrier that is disposed to face each of the image carriers is a transfer material. A color electron having transfer means for transferring to and from and advancing / retracting at least one of the plurality of process units between a position where the image carrier approaches and moves away from the transfer means A photographic device,
The contact / separation means includes an image carrier contact / separation lever that is arranged across a plurality of process units and advances / retreats in the arrangement direction of each process unit, and a drive unit that drives the image carrier contact / separation lever,
The image carrier contact / separation lever presses the image carrier to move away from the transfer means when moved in the separation direction, and the image when moved in the approach direction opposite to the separation direction. A color electrophotographic apparatus comprising: an urging portion that urges the carrier in a direction to approach the transfer unit; and a separation limiting member that holds the image carrier at the approach position.   2. The color electrophotographic apparatus according to claim 1, wherein the image carrier contact / separation lever moves forward and backward in a direction orthogonal to the axial direction of the image carrier. The image carrier includes an image carrier body, and shaft portions protruding from both ends of the image carrier body,
The pressing portion is in contact with both end shaft portions of the image carrier, and the image carrier is moved in the separation direction by pressing the both end shaft portions when the image carrier contact lever moves in the separation direction. The color electrophotographic apparatus according to claim 1, wherein the color electrophotographic apparatus is a color electrophotographic apparatus.   The process unit is composed of four process units corresponding to yellow, cyan, magenta, and black developers, and the contact / separation unit is configured to contact / separate process units related to a developer other than black. The color electrophotographic apparatus according to any one of claims 1 to 3, wherein:   The image carrier can be rotated forward and backward, and the image carrier is reversely rotated only when the image carrier is biased in the direction approaching the transfer means by the image carrier contact / separation lever. The color electrophotographic apparatus according to claim 1, wherein the color electrophotographic apparatus is a color electrophotographic apparatus.   The transfer means is capable of forward and reverse rotation, and the transfer means is reversely rotated only when the image carrier is biased in a direction approaching the transfer means by the image carrier contact lever. A color electrophotographic apparatus according to any one of claims 1 to 4. A casing having a casing main body that accommodates each of the process units, the transfer unit, and the contacting / separating unit; and a cover that opens and closes an opening of the casing main unit;
By operating in conjunction with the opening and closing operation of the cover, it is provided with an interlocking operation mechanism that operates the contact and separation means,
The interlock operation mechanism moves the image carrier contact / separation lever in the separating direction when the cover is opened, and does not move the image carrier contact / separation lever in the approaching direction when the cover is closed. The color electrophotographic apparatus according to claim 1, wherein:   The interlock operation mechanism includes a cover rotation gear that is fixed to the opening / closing shaft of the cover and rotates in conjunction with the cover opening / closing operation, a gear mechanism that sequentially transmits the rotational force from the cover rotation gear, and the gear mechanism The color electrophotographic apparatus according to claim 7, further comprising: a link mechanism that converts a rotational force of the image carrier into a linear motion and moves the image carrier contact / separation lever in the separation direction.

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