JPH07219294A - Color electrophotographic device - Google Patents

Abstract

PURPOSE:To provide a compact color electrophotographic device having a simple constitution, capable of obtaining a beautiful color image, and being excellent in maintainability. CONSTITUTION:The group of plural image forming units having toner whose color is different is wholly rotated and moved, and the respective units are successively moved to the same image forming position. At the image forming position, the image is formed by signal light in the image forming units 1BK, 1C, 1M and 1Y, and the toner image is transferred to an opposed intermediate transfer belt 32. The optical paths of the signal light 13 constituted by two adjacent image forming units are parallel and the width of a gap is set to <=20mm. The color of the armor of the image forming unit constituting the optical path is black and the side wall of the optical path is constituted of an image forming unit supporting body 6. Only one destaticizing lamp 7 for destaticizing the photoreceptor 9 is provided near an image forming position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color electrophotographic apparatus applicable to color printers, color copying machines, color fax machines and the like.

[0002]

2. Description of the Related Art Generally, in order to form a color image by electrophotography, a method of forming a color image by superposing toner images of respective colors of yellow, magenta, cyan and black on a transfer body is adopted. In recent years, in order to reduce the size of such an apparatus and simplify the maintenance, a plurality of image forming units as shown in JP-A-62-287264 are held on a rotary support, and one exposure is performed. There has been proposed an apparatus for forming a color image on a paper wound around a transfer body while replacing the image forming unit with respect to the means. An example of such a device will be described below with reference to FIG.

In FIG. 4, 101 is four image forming units 102a, 10a of cyan, magenta, yellow and black.
A rotating frame for rotatably supporting 2b, 102c, and 102d, which is held by a support shaft 103 and rotates at the timing of development.

The respective units containing the four color toners have the same structure, and only the toners are different. The structure of this image forming unit and the image forming process will be described in detail with respect to the image forming unit 102a stopped at the image forming position in FIG.

The image forming unit 102a has a sensitized photosensitive drum 108 of an organic photoconductor, a primary charger 110, and a cleaner unit 111. On the other hand, a semiconductor laser (not shown) is provided outside the image forming unit 102a, and the signal light output from the laser is axially formed on the photosensitive drum 108 by the polygon 106 rotated at a constant speed by the motor. Exposure scanning. In FIG. 4, 1
Reference numeral 07 is a lens system, and 104 is a mirror for changing the traveling direction of the laser light.

The signal light output from the semiconductor laser according to the image signal of each color exposes the photosensitive drum 108 uniformly charged by the charger 110 to form an electrostatic latent image.
Then, the electrostatic latent image is developed by the developing device 109 to form a toner image on the photosensitive drum 108. On the other hand, the transfer material is fed by the feed roller 114 and is evenly wound around the surface of the transfer drum 112. The toner image formed on the photoconductor drum 108 is transferred onto the transfer material wound around the transfer drum 112 by the transfer charger 113 provided inside the transfer drum 112.

After the transfer, the toner remaining on the photosensitive drum 108 is collected by the cleaner unit 111. Photoconductor drum 10 whose surface is cleaned by the cleaner unit 111
After being statically removed by the static elimination lamp 105, 8 stops rotating.

After the above-described image forming operation is completed, the rotary frame 101 is rotated by 90 ° and each unit is rotated by 90 °, so that the unit 10 is set at the lowermost image forming position.
Instead of 2a, the unit 102b moves, stops, and is fixed.

Next, an image is created using the unit 102b. For this, the semiconductor laser is modulated according to the image signal corresponding to the toner color of the unit 102b, and the unit 1
After the latent image is formed on 02b, development is performed and the transfer drum 11
The toner image that has already been transferred onto the transfer material wound around 2 is transferred in an overlapping manner. The following process is unit 1
This is the same as the case of 02a.

In this way, the image forming process is performed for each of the four units, and the toner images of four colors are superposed on the transfer material held on the transfer drum 112 to form a color image. The transfer material on which the color image is formed is separated from the transfer drum 112 by the separation claw 115. Thereafter, the transfer material is conveyed on the conveyor belt 116, the toner image is fixed by the fixing device 117, and then the transfer material is ejected onto the tray 118.

[0011]

When an image is output by the above-mentioned device, the gap between two adjacent image forming units which are held on the rotary support and constitute a part of the optical path is large, and Since various gaps were opened on the side surface of the image forming unit group installed in the apparatus, the heat lamp of the fixing device and other external light become stray light and enter the optical path, and The surface potential was lowered to cause thin fog of toner in the background portion of the image. Further, when the static elimination lamp provided in the center of rotation of the image forming unit group is turned on, a part of this static elimination light also becomes stray light and enters the optical path of the signal light, lowering the surface potential of the photoconductor. , A thin fog of the toner was generated.

In view of the above problems, it is an object of the present invention to provide a small color image having excellent maintainability and capable of outputting a good color image without causing a thin toner fog due to stray light when the image is output. A device is provided.

[0013]

In order to achieve the above object, the present invention comprises an electrostatic image bearing member, each of which rotates at least, and a developing unit having a developer of a different color. A plurality of image forming units capable of forming toner images of different colors on the electric image carrier, and a transfer member capable of forming a color image by superposing the toner images of the plurality of colors formed by the image forming unit; Transfer means for transferring the toner image on the electrostatic image carrier to the transfer body at a single transfer position, and exposure means for performing image exposure at a single exposure position corresponding to the transfer position, Moving means for rotating the entire image forming unit group to sequentially position each of the plurality of image forming units to the image forming position corresponding to the exposure position and the transfer position, and the plurality of image forming units. A support member that supports a group and that is rotated by the moving unit, and a gap between two adjacent image forming units of the plurality of image forming unit groups is a wall that surrounds an optical path of the exposing unit. Of at least one of the two image forming units, the end faces forming the optical path walls of the two image forming units being planes substantially parallel to each other when the image forming unit group is supported by the support. It is a color electrophotographic device that does.

Further, the present invention comprises an electrostatic image bearing member, each of which rotates at least, and a developing means having a developer of a different color, and toner images of different colors are provided on the electrostatic image bearing member. A plurality of image forming units, a transfer member capable of forming a color image by superposing the toner images of a plurality of colors formed by the image forming unit, and a single transfer position on the electrostatic image carrier. The transfer means for transferring the toner image of 1. to the transfer body, the exposure means for performing image exposure at a single exposure position corresponding to the transfer position, and the plurality of image forming units, respectively. Moving means for rotationally moving the entire image forming unit group so as to sequentially position the image forming positions corresponding to and corresponding to the transfer position, and a plurality of image forming unit groups are supported and rotated by the moving means. A support, and a gap between two adjacent image forming units of the plurality of image forming unit groups forms at least one pair of walls surrounding an optical path of the exposure unit, and In the color electrophotographic apparatus, the gap between the two image forming units is 20 mm or less when the image forming unit group is supported by the support.

Further, the present invention is provided with electrostatic image bearing members, each of which rotates at least, and developing means having a developing agent of a different color, and toner images of different colors are formed on the electrostatic image bearing member. A plurality of image forming units, a transfer member capable of forming a color image by superposing the toner images of a plurality of colors formed by the image forming unit, and a single transfer position on the electrostatic image carrier. The transfer means for transferring the toner image of 1. to the transfer body, the exposure means for performing image exposure at a single exposure position corresponding to the transfer position, and the plurality of image forming units, respectively. Moving means for rotationally moving the entire image forming unit group so as to sequentially position the image forming positions corresponding to and corresponding to the transfer position, and a plurality of image forming unit groups are supported and rotated by the moving means. A support, and a gap between two adjacent image forming units of the plurality of image forming unit groups forms at least one pair of walls surrounding an optical path of the exposure unit, and The color electrophotographic apparatus is characterized in that at least two image forming units have a black color on an end face forming the optical path wall.

Further, the present invention comprises an electrostatic image bearing member, each of which rotates at least, and a developing means having a developer of a different color, and the toner image of a different color is provided on the electrostatic image bearing member. A plurality of image forming units, a transfer member capable of forming a color image by superposing the toner images of a plurality of colors formed by the image forming unit, and a single transfer position on the electrostatic image carrier. The transfer means for transferring the toner image of 1. to the transfer body, the exposure means for performing image exposure at a single exposure position corresponding to the transfer position, and the plurality of image forming units, respectively. Moving means for rotationally moving the entire image forming unit group so as to sequentially position the image forming positions corresponding to and corresponding to the transfer position, and a plurality of image forming unit groups are supported and rotated by the moving means. A support, and two adjacent image forming units of the plurality of image forming unit groups in a direction parallel to the scanning surface of the exposing unit among the walls surrounding the optical path of the exposing unit. In the color electrophotographic apparatus, an optical path wall is formed, and the support of the image forming unit forms an optical path wall in a direction perpendicular to the scanning surface of the exposing means.

Further, the present invention is provided with an electrostatic image bearing member, each of which rotates at least, and a developing means having a developer of a different color, and the toner image of a different color is provided on the electrostatic image bearing member. A plurality of image forming units, a transfer member capable of forming a color image by superposing the toner images of a plurality of colors formed by the image forming unit, and a single transfer position on the electrostatic image carrier. The transfer means for transferring the toner image of 1. to the transfer body, the exposure means for performing image exposure at a single exposure position corresponding to the transfer position, and the plurality of image forming units, respectively. Moving means for rotationally moving the entire image forming unit group so as to sequentially position the image forming positions corresponding to and corresponding to the transfer position, and a plurality of image forming unit groups are supported and rotated by the moving means. A support, and a charge removing unit that can remove the surface charge of the electrostatic image bearing member outside the rotational movement of the plurality of image forming unit groups and near the image forming position. It is an electrophotographic device.

[0018]

In the above construction, the gap between the adjacent image forming units is formed by a plane substantially parallel to each other. Therefore, by aligning this plane substantially parallel to the scanning plane of the signal light, the gap can be narrowed without obstructing the optical path. , And can be long. Furthermore, when the gap between adjacent image forming units is large, the amount of stray light entering the optical path of the signal light also increases, and the surface potential of the photoconductor is significantly reduced by the stray light, but the gap width is 20 mm.
By the following, it is possible to reduce stray light that enters the optical path of the signal light, and to prevent a decrease in the surface potential of the photoconductor due to stray light. Furthermore, by making the portion of the image forming unit that forms the optical path wall black, the reflected light of stray light is weakened even when stray light enters the optical path, and the effect of stray light on the photoconductor surface potential can be reduced. . Further, in addition to the wall surface parallel to the scanning surface of the signal light being configured by a part of the image forming unit, the wall surface (side wall of the optical path of the signal light) perpendicular to the scanning surface is configured by the image forming unit support By doing so, it is possible to reduce the invasion of stray light from the side surface of the unit rotational movement when the image forming unit is mounted on the support. Further, each image forming unit can be miniaturized by providing only one charge removing unit for the photoconductor outside the rotational movement of the unit and on the main body side near the image forming position. Further, when the light removing means such as an LED or a lamp is used as the charge removing means, in comparison with the case where the charge removing lamp is provided in the central area of the unit rotation as in the conventional example, the charge removing light is prevented from entering the signal light optical path. The surface potential of the photoconductor can be kept constant even when the charge eliminating lamp is turned on, and the temperature of the rotation center region of the image forming unit group due to the lamp does not rise, resulting in stable and favorable operation. Can output color images.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A color electrophotographic apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall configuration diagram of a color electrophotographic apparatus according to an embodiment of the present invention. First, black, yellow in the center,
Four sets of fan-shaped image forming units 1Bk, 1Y, 1M, and 1C for each color of magenta and cyan constitute an image forming unit group, and are arranged in an annular shape as shown in the drawing. Since each image forming unit is made of the same constituent member except for the developer contained therein, the image forming unit for black will be described and the other colors will be omitted for simplification of description. Note that, for each color, the same portions are denoted by the same reference numerals, and when it is necessary to distinguish each color, the reference numerals are attached to indicate the respective colors. FIG. 2 shows the black image forming unit 1B.
Details of k are shown.

In FIG. 2, 9 is an organic photoreceptor in which phthalocyanine is dispersed in a polycarbonate binder resin, 1
0 is a charging roller for negatively charging the photoconductor, 13 is a signal light by a laser beam, 14a is a first hopper containing a developer in which a carrier and toner are mixed, and 14b is a first hopper containing only toner. Two hoppers, 15 is an opening opened for replenishing toner, 16 is a lid for opening and closing the opening 15, 17 is an agitator for replenishing toner, and 18a and 18b are developers in the first hopper 14a. Is an agitator for transporting the toner to the developing portion.

Reference numeral 19 is a rotatable developing electrode roller made of aluminum, 20 is a non-rotating magnet fixed coaxially inside thereof, 21 is an AC high voltage power source for applying a voltage to the developing electrode roller 19, and 22 is on the electrode roller 19. It is a magnetic blade that regulates the toner layer thickness. The diameter of the photoconductor 9 is 30 m
The electrode roller 19 was rotated at a peripheral speed of 60 mm / s in the arrow direction, and the electrode roller 19 was rotated at a peripheral speed of 60 mm / s in the arrow direction.

In the first hopper 14a, a two-component developer 26 is prepared by mixing a toner carrier 25Bk with a ferrite carrier 24Bk having a particle size of 50 μm, the surface of which is coated with a silicone resin.
Bk was added and magnetically attached to the surface of the photoconductor 9. The toner used is one in which a pigment or the like is dispersed in a polyester resin and an additive is further added.

In the second hopper 14b, 400 g of toner is hermetically stored at the time of assembling the image forming unit, and 5000 sheets of A4 monochromatic 5% originals can be output without supplying toner from outside the unit. ing.

Reference numeral 27 is a cleaner for cleaning the toner remaining on the surface of the photoconductor after transfer. The operation of the image forming unit configured as described above will be described below with reference to FIG.

The photosensitive member 9 is charged by the charging roller 10 at -700V.
Charged to. The photoconductor 9 was irradiated with the signal light 13 by the laser beam to form an electrostatic latent image. At this time, the exposure potential of the photoconductor was -100V.

The surface of the photoreceptor 9 is covered with a two-component developer 26B.
K was carried and passed in front of the rotating electrode roller 19.
At this time, when the photoconductor 9 passes through the uncharged area, an AC high voltage power source 21 superimposes a DC voltage of +100 V on the electrode roller 19 and an AC voltage of 750 V 0-p (peak-to-peak 1.5 kV) (frequency). (1.8 kHz) was applied. After that, when passing the surface of the photoconductor 9 charged to -700V and having the electrostatic latent image written therein, 750V0-p (peak-to-peak) in which a DC voltage of -400V is superposed on the electrode roller 19 by an AC high voltage power source 21. An AC voltage (frequency 1.8 kHz) having a peak of 1.5 kV was applied. Then,
On the photosensitive member 9, a negative-positive inverted toner image remained only in the image portion.

In this way, a black toner image is obtained on the photosensitive member 9. The image forming unit in FIG. 2 is a black image forming unit, and also shows the upper and lower positions of the image forming unit at the image forming position. Toner 25Bk in the figure
The second developer hopper 14b containing the developer is the first hopper 14a.
Since the cleaner 27 is located on the upper side of the cleaner, the toner can be smoothly replenished and cleaned without providing a feeding mechanism or a stirring mechanism for moving the developer or toner inside the toner hopper 14b or inside the cleaner. It can be performed. That is, in the toner hopper 14b, the toner is supplied to the vicinity of the opening 15 by the rotational movement of the unit and its own weight,
In the cleaner, the toner scraped off by the blade falls to the bottom of the cleaner by its own weight and separates from the photoconductor.

Further, 28 is a photoconductor cover for protecting the photoconductor 9, which is shown in FIG. 2 in an opened state for image formation. The photoconductor cover 28 covers the photoconductor when the image forming unit is located at a position other than the image forming position, and prevents the photoconductor from being contaminated and the inside of the machine from being contaminated by toner when the unit is rotationally moved.

Other developing devices 1Y, 1M, 1C other than black have the same structure and operate.

The configuration of the printer unit will be described again with reference to FIG. Image forming unit 1B arranged in an annular shape
k, 1Y, 1M, and 1C are supported by a support body 6 and are driven by a moving motor 30 which is a moving means controlled by a control circuit 29 as a whole, and around a cylindrical fixed and non-rotating shaft 31. It can be rotated in the direction of the arrow. Each image forming unit has an image forming position 5 facing a transfer roller 33 that supports an intermediate transfer belt 32, which will be described later.
Moved to 0 and positioned. The image forming position 50 is also an exposure position by the signal light 13. Image forming unit 1B
The K, 1Y, 1M, and 1C supports 6 have means (not shown) for detecting that each image forming unit has moved to the image forming position 50, and the movement is completed each time the movement of each unit is completed. To the control circuit 29.

Reference numeral 3 denotes a laser exposure device, which is a signal light 13 by a laser beam modulated by a signal input to the printer section.
Of the image forming units 1Bk and 1Bk of FIG.
After passing through the optical path formed between the fan-shaped portions of C, the light enters the mirror 5 fixed inside the shaft 31 through the transparent window 4 opened in a part of the shaft 31, and is reflected to the image forming position 50. The photoconductor 9 of an image forming unit is irradiated with the latent image to form a latent image.
In the state of FIG. 1, it acts on the black image forming unit 1Bk.

FIG. 3 is an enlarged view of a portion of an optical path formed by two image forming units adjacent to each other. Here, the optical path to the mirror 5 is composed of parallel end faces of two fan-shaped image forming units adjacent to each other, and the width of the optical path formed by the end faces of the units is 10 mm and the length of the optical path is 70 m.
m, the optical path length from the outer periphery of the unit to the mirror is 100
mm. In addition, the end surface of the unit forming the optical path is formed in the entire region from the front side to the back side of the support 6 in the longitudinal direction, and further, in the portion where the image forming unit and the support 6 come into contact with each other, The gap is made as small as possible to prevent stray light from entering through the gap. The side wall of the optical path is formed by the support 6 of the unit to prevent stray light from entering from the side surface. In addition, the color of the exterior of the image forming unit is black, which reduces the reflected light of stray light entering the optical path on the wall surface of the optical path, and prevents stray light from penetrating deeply and lowering the surface potential of the photoconductor. There is.

In FIG. 1, 7 is an LED (wavelength 660n
m) is a static eliminating lamp located at the image forming position 50,
During the image formation, the surface of the photoconductor 9 after the transfer of the toner image is irradiated to remove the surface charge remaining on the photoconductor 9.

Reference numeral 60 denotes a magnetic resistance type toner density sensor installed on the shaft 31.
First hopper 1 of the image forming unit when positioned in
It is located so that the toner density in 4a can be detected.

Reference numeral 32 is an intermediate transfer belt having a thickness of 100 μm.
Endless belt-like semi-conductive urethane film as a base material, wound around a transfer roller 33 and a stainless steel roller 34 formed of urethane foam with low resistance treatment, and movable in the arrow direction. Has become.

The transfer roller 33 is lightly pressed against the photosensitive member 9 of the unit 1Bk at the image forming position via the intermediate transfer belt 32. A second transfer roller 35, which has the same structure as the transfer roller 33, is pressed against the roller 34 via the intermediate transfer belt 32 so as to be driven and rotated.

Intermediate transfer belt 32 and second transfer roller 35
A sheet conveying path is formed in the nip portion which is pressed against the sheet so that the sheet is fed from the sheet feeding section 36.

A belt cleaner 40 includes a belt cleaner for cleaning the intermediate transfer belt.

Reference numeral 44 is a fixing device for fixing the toner image on the paper after transfer, and 45 is a discharging roller for discharging the paper after fixing.

The above is the description of the main structures of the electrophotographic apparatus and the image forming unit of the present invention. Next, the operation of this apparatus when forming a color image will be described.

First, each image forming unit is in the position as shown in FIG. 1, and the image forming unit 1Bk for black is used.
Is positioned at the image forming position 50, and the toner density sensor 60 is positioned so as to be substantially in contact with the side wall of the image forming unit. This position 50 is also a position facing the transfer roller 33. Black signal light is input to the image forming unit 1Bk by the laser exposure device 3, the operation of the image forming unit is started, and an image is formed with black toner. Simultaneously with the start of image formation, the toner concentration sensor 60 starts detecting the toner concentration of the developer in the first hopper 14a,
According to the detection signal, when the toner in the first hopper 14a is insufficient, the agitator 17 pushes the lid 16 open to replenish the toner.

The image forming speed of the image forming unit 1Bk (equal to the peripheral speed of the photosensitive member) and the moving speed of the intermediate transfer belt are set to be the same, and at the same time the image is formed, the transfer roller 33 acts at the same time. Then, the black toner image is transferred to the intermediate transfer belt. Image forming unit group 1Bk, 1
The Ys, 1Ms, and 1Cs are wholly driven by the movement motor 30 to integrally rotate and move in the direction of the arrow in FIG. 1 and rotate exactly 90 ° to stop at the position where the image forming unit 1Y reaches the image forming position 50. The image forming unit 1Y is positioned. Since the parts other than the photoconductor of the image forming unit are located inside the rotation arc of the tip of the photoconductor, the intermediate transfer belt does not come into contact with the image forming unit. As before, this time the laser exposure device inputs the signal light to the image forming unit 1Y with the yellow signal to form and transfer the yellow toner image. At this time, the writing timing of the yellow signal light is controlled so that the next yellow toner image is positionally aligned with the black toner image previously transferred onto the intermediate transfer belt 32. During this time, the second transfer roller 35 and the cleaner unit 40 are slightly separated from the intermediate transfer belt so that nothing acts on the toner image thereon.

The same operation as described above is performed for magenta and cyan, and four color toner images are positionally aligned and superposed on each other on the intermediate transfer belt to form a color image. After the final transfer of the cyan toner image, the four color toner images are collectively transferred onto the paper fed from the paper feed section 36 at the same timing by the action of the second transfer roller 35. The toner image transferred onto the paper is fixed by the fixing device 44. The sheet is then discharged to the outside of the apparatus via the discharge roller 45. The transfer residual toner remaining on the intermediate transfer belt is cleaned by the action of the cleaner unit 40 to prepare for the next image formation.

Next, the operation in the monochromatic mode will be described. In the monochromatic mode, first, the image forming unit of a predetermined color is moved to the image forming position and positioned. Next, the same color image formation and transfer to the intermediate transfer belt are performed in the same manner as before, and this time after transfer, the transfer is continued as it is, and the transfer is performed on the paper sent from the paper supply unit by the next second transfer roller. I will do it.

The above is the description of the configuration and operation of the embodiment.
According to the present invention, since the image formation of each color is performed at the same image forming position without using a transfer drum having a complicated configuration, the present invention can perform accurate color registration with a simple configuration, and The image forming unit is completed independently as one image forming unit for each color, the configuration is simple, and it is easy to replace each color. Become.

Further, in this configuration, the optical path of the signal light composed of two adjacent image forming units can be narrowed, the device can be made small, and stray light is less likely to enter the optical path. Further, by making the color of the exterior of the image forming unit black so that light is less likely to be reflected, it is possible to reduce the influence of stray light on the image.

Further, in this configuration, since each image forming unit including the photoconductor can be independently adjusted externally, it is possible to easily replace a unit which has already been adjusted at the time of factory shipment without any adjustment on site. is there.

Since the photoconductor is covered except when the image is formed, the photoconductor is not damaged or soiled, and the interior of the device is not soiled by the scattering of the developer.

Further, in this configuration, since the size of the intermediate transfer member can be reduced, the apparatus can be downsized, and the toner images of the respective colors can be easily and accurately aligned on the intermediate transfer member.

In this configuration, the toner images of the respective colors are superposed on the intermediate transfer belt as the intermediate transfer member to form a color image. However, a drum is used as the intermediate transfer member and the toner images of the respective colors are superposed on each other to form a color image. Even in the configuration for forming an image, a paper as a transfer material is held on an intermediate transfer body in the form of a drum and a belt, and toner images of respective colors are directly transferred onto the transfer material and sequentially superimposed to form a color image. Even with the configuration formed, the essence of the present invention and the operational effects do not change.

Further, in the above embodiments, the two-component developing method in which the carrier and the toner are mixed is used as the developing method used in the image forming unit, but the essence of the present invention is obtained even in the case of the one-component developing method using only the toner. And the effect is the same.

[0053]

As described above, the present invention has a simple structure because a transfer drum having a complicated structure is not used, and since image formation for each color is performed at the same image forming position,
Accurate color registration can be performed with a simple structure. By making the optical paths of the signal light composed of two adjacent image forming units parallel and narrowing them, and by making the exterior color of the part forming the optical path black, the effect of stray light on the image is eliminated A color image can be obtained. By providing only one static elimination lamp on the photoconductor in the vicinity of the image forming position, the size of the image forming unit can be reduced and the influence of the static elimination lamp on the image can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a color electrophotographic apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of an image forming unit used in a color electrophotographic apparatus according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of an optical path of signal light formed by an image forming unit of a color electrophotographic apparatus according to an exemplary embodiment of the present invention.

FIG. 4 is a block diagram of a conventional color electrophotographic apparatus.

[Explanation of symbols]

 1Bk, 1C, 1M, 1Y Image forming unit 3 Laser exposure device 5 Mirror 6 Support 9 Photoconductor 13 Signal light 28 Photoconductor cover 32 Intermediate transfer belt 33 Transfer roller 35 Second transfer roller 50 Image forming position 60 Toner density sensor

Claims (6)

[Claims] 1. An electrostatic image carrier, each of which rotates at least, and a developing unit having a developer having a different color, and toner images of different colors can be formed on the electrostatic image carrier. A plurality of image forming units, a transfer body capable of forming a color image by superposing the toner images of a plurality of colors formed by the image forming unit, and a toner image on the electrostatic image carrier at a single transfer position A transfer unit for transferring the image to the transfer body, an exposure unit for performing image exposure at a single exposure position associated with the transfer position, and a plurality of image forming units each corresponding to the exposure position. A moving unit that rotates and moves the entire image forming unit group to sequentially position the image forming units corresponding to the transfer position; and a support that supports the plurality of image forming unit groups and that is rotated by the moving unit. A gap between two adjacent image forming units of the plurality of image forming unit groups forms at least one pair of walls surrounding the optical path of the exposure unit, and the image forming unit group The color electrophotographic apparatus, wherein end faces forming the optical path walls of the two image forming units in a state of being supported by the support are planes substantially parallel to each other. 2. An electrostatic image carrier, each of which rotates at least, and a developing unit having a developer having a different color, and toner images of different colors can be formed on the electrostatic image carrier. A plurality of image forming units, a transfer body capable of forming a color image by superposing the toner images of a plurality of colors formed by the image forming unit, and a toner image on the electrostatic image carrier at a single transfer position A transfer unit for transferring the image to the transfer body, an exposure unit for performing image exposure at a single exposure position associated with the transfer position, and a plurality of image forming units each corresponding to the exposure position. A moving unit that rotates and moves the entire image forming unit group to sequentially position the image forming units corresponding to the transfer position; and a support that supports the plurality of image forming unit groups and that is rotated by the moving unit. A gap between two adjacent image forming units of the plurality of image forming unit groups forms at least one pair of walls surrounding the optical path of the exposure unit, and the image forming unit group A color electrophotographic apparatus, wherein a gap between the two image forming units is 20 mm or less in a state of being supported by the support. 3. The color electrophotographic apparatus according to claim 2, wherein the optical path walls formed by two image forming units adjacent to each other are flat surfaces substantially parallel to each other. 4. An electrostatic image bearing member, each of which rotates at least, and a developing unit having a developer of a different color, and toner images of different colors can be formed on the electrostatic image bearing member. A plurality of image forming units, a transfer body capable of forming a color image by superposing the toner images of a plurality of colors formed by the image forming unit, and a toner image on the electrostatic image carrier at a single transfer position A transfer unit for transferring the image to the transfer body, an exposure unit for performing image exposure at a single exposure position associated with the transfer position, and a plurality of image forming units each corresponding to the exposure position. A moving unit that rotates and moves the entire image forming unit group to sequentially position the image forming units corresponding to the transfer position; and a support that supports the plurality of image forming unit groups and that is rotated by the moving unit. A gap between two adjacent image forming units of the plurality of image forming unit groups forms at least one pair of walls surrounding the optical path of the exposure unit, and at least two image forming units A color electrophotographic apparatus, wherein an end face forming the optical path wall of the unit is black. 5. An electrostatic image bearing member, each of which rotates at least, and a developing unit having a developer of a different color, and toner images of different colors can be formed on the electrostatic image bearing member. A plurality of image forming units, a transfer body capable of forming a color image by superposing the toner images of a plurality of colors formed by the image forming unit, and a toner image on the electrostatic image carrier at a single transfer position A transfer unit for transferring the image to the transfer body, an exposure unit for performing image exposure at a single exposure position associated with the transfer position, and a plurality of image forming units each corresponding to the exposure position. A moving unit that rotates and moves the entire image forming unit group to sequentially position the image forming units corresponding to the transfer position; and a support that supports the plurality of image forming unit groups and that is rotated by the moving unit. Of the plurality of image forming unit groups, two adjacent image forming units form an optical path wall in a direction parallel to the scanning surface of the exposing means among walls surrounding the optical path of the exposing means. A color electrophotographic apparatus, wherein the support of the image forming unit forms an optical path wall in a direction perpendicular to the scanning surface of the exposure unit. 6. An electrostatic image bearing member, each of which rotates at least, and a developing unit having a developer having a different color, and toner images of different colors can be formed on the electrostatic image bearing member. A plurality of image forming units, a transfer body capable of forming a color image by superposing the toner images of a plurality of colors formed by the image forming unit, and a toner image on the electrostatic image carrier at a single transfer position A transfer unit for transferring the image to the transfer body, an exposure unit for performing image exposure at a single exposure position associated with the transfer position, and a plurality of image forming units each corresponding to the exposure position. A moving unit that rotates and moves the entire image forming unit group to sequentially position the image forming units corresponding to the transfer position; and a support that supports the plurality of image forming unit groups and that is rotated by the moving unit. A color electrophotographic apparatus, wherein the plurality of the rotary movement outside of the image forming unit group, and provided discharging means capable of neutralizing the surface charge of the latent electrostatic image bearing member in the vicinity of the image forming position.