JPH05323757A - Image forming device - Google Patents

Abstract

PURPOSE:To make the whole of an image device compact by executing an image exposure for forming, at least, a kind of electrostatic latent image, out of plural kinds of electrostatic latent image, by means of the transmission of a conducting substrate having light transmissivity. CONSTITUTION:A movable belt photosensitive body 1 as a belt-like image forming body, is stretched between a driving roller 2 and a driven roller 3 and carried clockwise. For the belt photosensitive body 1, a transparent base 1a is used, and coated with a photosensitive layer 1b. On the other hand, as the transparent base 1a of the conducting substrate, a polyester material is used, and as the photosensitive layer 1b, one mainly composed of a carrier generating layer and a carrier transporting layer, is formed. Thus, for the base of the belt photosensitive body 1, the transparent base 1a is used, and an image forming body having the formation of the photosensitive layer 1b on the transparent base 1a, is formed. An exposure is attained from the rear side of the belt photosensitive body 1 endlessly formed, that is, the side of the transparent base 1a. Therefore, an exposing means can be provided inside the belt photosensitive body 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention exposes the back side of a belt-shaped image forming body by an electrophotographic method, forms a unit together with a developing device, and forms a color toner image on the belt-shaped image forming body. The present invention relates to a color image forming apparatus that forms a toner image and transfers the toner image onto a transfer paper to obtain an image.

[0002]

2. Description of the Related Art Conventionally, when a multicolor image is formed by an image forming apparatus using, for example, an electrophotographic method, charging, exposing, developing and transferring are repeated for each color, and toner images of respective colors are superposed and transferred on a recording paper. I am trying to do it. For example, an electrostatic latent image for each color is formed on the photoconductor by using separation light of blue, green, red, etc. obtained through a color separation filter, and yellow, magenta, cyan and, if necessary, black toner It is known that a toner image of each color is formed by developing with a toner and the toner image of each color is transferred onto a recording paper to form a multicolor image.

Further, for example, JP-A-56-144452, Japanese Patent Application No. 58-184381, and JP-A-58-18 previously filed by the present applicant.
No. 3152 and Japanese Patent Application No. 58-187000 disclose that plural toner images are superposed on the same photosensitive member and developed so that one transfer step is sufficient and the first toner image is developed. Other than the above, an image forming apparatus has been proposed which is developed in a non-contact manner.

Further, in order to downsize the entire apparatus, a belt-shaped image forming body (hereinafter referred to as a belt photosensitive member) is stretched between two axes, and a plurality of toners of different colors are accommodated along the lower side thereof. A plurality of developing devices are arranged, and while the belt photoconductor is rotated a plurality of times, latent image formation according to the number of separated colors of the original image on the belt photoconductor and development of the development device group by the development device group are performed. A color copy can be obtained by transferring onto a transfer paper fed from a paper feed cassette in a cassette storage chamber provided on the lower side.

Unlike the photoconductor drum, the belt photoconductor of such a color image forming apparatus can make a U-turn with a small curvature, so that it can be run flat and the space can be effectively used. Further, the separation pole of the transfer paper after the transfer is provided in the small-diameter curvature portion which makes the U-turn, so that the separation of the transfer paper is improved.

However, the belt photosensitive member is suspended in the main body of the image forming apparatus between the driving roller and the driven roller, and when the belt photosensitive member is replaced, either or both of the driving roller and the driven roller are removed from the shaft and replaced. Is being done. At this time, since the developing device is also provided in the main body, a method of removing and replacing the belt photosensitive member after pulling out the developing devices (four in the case of color) from the main body is used. As a method of exposing the belt photosensitive member, a laser writing means is mainly used from the outside of the belt photosensitive member.

[0007]

As described above, since it is necessary to repeat the transfer cycle for each color, the size of the entire apparatus becomes large, the image forming process becomes complicated, and the operation time is lost and the operation is repeated. Since the toner images of the respective colors are displaced, it is difficult to guarantee the accuracy of image formation. Further, when the color toner is subjected to the second and subsequent image exposures, since the toner image previously developed is always present, the image exposure light radiated to the area of the toner image to which the toner adheres. However, there is a problem in that it cannot be sufficiently transmitted through the photoconductor. Further, even in the image forming apparatus using the belt-shaped image forming body configured to improve the enlargement, even if the miniaturization is solved, the above-mentioned color toner is formed in the photoreceptor when the image exposure for the second and subsequent colors is performed. Means for sufficiently transmitting light have not been solved, which has been a major bottleneck in color image formation. Further, as described above, the belt photosensitive member is attached to the main body through the driving roller and the driven roller, and the belt photosensitive member cannot be removed from the main body unless the roller is removed from the shaft. There was a great deal of trouble in replacing. If a color developing device is provided at the same time, it is necessary to pull out and remove four developing devices from the main body. At that time, the developer and the belt photosensitive member come into contact with each other, and the developer falls into the machine or scatters. It was a cause of soiling the inside of the device. Further, a belt electrode for giving an electric charge to the belt photosensitive member is also fixed in the apparatus and is arranged close to the belt photosensitive member. In this case, in particular, when a new belt photosensitive member is attached to the driving roller and the driven roller and set in the apparatus, there is a risk that the belt electrode may come into contact with the photosensitive member surface of the belt photosensitive member, so that it is necessary to remove the belt electrode. As described above, it takes a lot of time and labor to replace the belt photosensitive member. Further, since the exposing means is provided outside the belt photosensitive member, there is a drawback that the entire apparatus is enlarged.

[0008]

In order to solve the above-mentioned problems of the present invention, the invention according to the first aspect is directed to a belt-shaped photoconductor having a photosensitive layer provided on a conductive substrate, and the belt photoconductor. An image forming apparatus having a plurality of developing devices for developing a plurality of types of electrostatic latent images formed on the belt photosensitive member, wherein a plurality of toner images are superposed on the belt photosensitive member. An image, characterized in that the conductive substrate is light-transmissive, and image exposure for forming at least one of the plurality of types of electrostatic latent images is carried out through the light-transmissive conductive substrate. The forming device has solved the above-mentioned transmission performance.

According to a second aspect of the present invention, the exposure means is provided inside the belt photosensitive member to further improve the exposure performance and to downsize the entire apparatus.

According to a third aspect of the present invention, the exposing means is fixed to the main body of the image forming apparatus, and the belt photosensitive member together with the suspension member can be pulled out from the main body of the image forming apparatus to facilitate replacement.

According to a fourth aspect of the present invention, a unit in which the belt photosensitive member, the suspension member and the developing device are integrated with each other can be pulled out from the main body of the image forming apparatus, and the developer of the belt photosensitive member and the developing device can be easily replaced.

According to a fifth aspect of the present invention, the belt photosensitive member, the suspension member, the developing device, and the band electrode are integrally formed so that they can be pulled out from the main body of the image forming apparatus, and the whole is covered.

According to a sixth aspect of the present invention, the exposure means is provided in the image forming unit and is detachably provided from the unit to form the entire image forming unit as a set, thereby facilitating production and mounting the exposure means. The removal was facilitated and the image formation at the time of image formation was improved.

According to a seventh aspect of the present invention, when the image forming unit is detached, the exposing means provided in the unit is detached, and then the entire unit is detached from the main body of the image forming apparatus to facilitate the detaching work of the image forming unit. did.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an explanation will be given based on an embodiment shown in the accompanying drawings of the present invention.

In FIG. 1, reference numeral 1 denotes a flexible belt photosensitive member which is a belt-shaped image forming member, and the belt photosensitive member is suspended between a driving roller 2 and a driven roller 3 and conveyed in a clockwise direction. A transparent base 1a is used as the belt photosensitive member 1, and a photosensitive layer 1b is applied on the transparent base.
A polyester material is used as the transparent base 1a of the conductive substrate, and the photosensitive layer 1b is formed of a photosensitive layer mainly composed of a carrier generating layer and a carrier transporting layer.

Reference numerals 4, 4a, 4b and 4c are guide members fixed to the main body of the apparatus so as to be inscribed in the lower side portion of the belt photosensitive member 1, and 5 are tension members for inwardly contacting the belt photosensitive member 1 to bring them into tension. Is. Guide members 4, 4a, 4
b, 4c and the tension member 5 make it possible to form a stable image forming surface on the belt photosensitive member 1.

6 is a scorotron charger which is a charging means, and 6
A is a cleaner for cleaning the wire of the charger 6. Reference numeral 7 is a laser writing system unit which is an image exposing means. For the laser writing system unit 7, an optical system in which a light emitting portion and a converging optical transmission body are integrated can be used in addition to the optical system shown.

Numerals 8, 9, 10, and 11 are developing devices as a plurality of developing means respectively containing developers of different colors, for example, yellow, magenta, cyan, and black developers, and the developing devices 8 to 11 are The guide members 4, 4a, 4b, 4c are arranged so as to face the photosensitive layer 1b of the belt photosensitive body 1 inscribed therein. In each of these developing devices 8-11, developing sleeves 8A, 9A, 10 for keeping a predetermined gap with the photosensitive layer 1b of the belt photosensitive member 1 are provided.
A and 11A are provided, and the latent image on the photosensitive layer 1b is visualized by a non-contact developing method. Unlike the contact development, this non-contact development has an advantage that the movement of the belt photosensitive member 1 cannot be prevented.

Reference numeral 12 is a transfer device, 12A is a charge eliminating bar, and 13 is a cleaning device. Blade 13A of cleaning device 13
The toner transport roller 13B keeps the photosensitive layer 1b during the image formation.
Is kept at a position separated from the surface of the photosensitive layer 1b and is pressed against the surface of the photosensitive layer 1b only as shown in the figure during cleaning after image transfer.

The color image forming apparatus includes a belt photosensitive member 1 suspended from the driving roller 2 and a driven roller 3,
A laser writing system unit 7 of exposure means, a developing device 8,
9, 10, 11 and the charger 6 are configured as an integrated image forming unit 14 as shown in FIG. 1, and the image forming unit 14 is mounted on the guide members 16, 17, 18 provided in the main body 15 of the image forming apparatus. Secure with screws. The laser writing system unit 7 includes guide members 19 and 20 provided in the image forming unit 14.
It is placed and fixed on. Reference numeral 21 denotes a protective cover that is openably and closably attached to the outside of the image forming unit 14. When the image forming unit 14 is detached, the protective cover 21 is rotated in the closing direction about a rotation shaft 21A by a spring member or the like (not shown). Is provided so as to protect the belt photosensitive member 1 exposed to the transfer device 12. Further, a cover 22 for preventing dust intrusion is attached to the exposure slit 7a of the laser writing system unit 7 so as to be openable and closable at the time of removal. Further, it is provided with a structure which is closed by a spring (not shown).

FIG. 2 is a cross-sectional view of the image forming apparatus main body 15. The shaft 2A of the driving roller 2 provided in the laser writing system unit 7 is provided with a coupling 23 and is provided in the image forming apparatus main body 15. The coupling 23 is detachably coupled to a drive member 24 driven by a drive motor M.

The guide members 16 and 17 are fixed to two stays 24 and 25 provided on the main body 15 of the image forming apparatus.
As a method of driving the developing units 8, 9, 10, and 11, a coupling C is provided so as to project from each developing unit, and a clutch (not shown) is provided by a drive source provided separately by the drive motor M.
To switch the operation and drive. 26 is the main body of the image forming apparatus
It is an opening / closing lid provided in front of 15.

First, formation of a multicolor image according to the embodiment of FIG. 1 is performed according to the following system. The image forming apparatus body
When a color signal output from an image reading device separate from 15 is input to the laser writing system unit 7, a laser beam generated by a semiconductor laser (not shown) in the laser writing system unit 7 is driven by a drive motor. The fθ lens 27 is rotated and scanned by the polygon mirror 27B rotated by 27.
After passing through C, the optical path is bent by the mirror 27D, and a bright line is projected through the transparent base 1a onto the peripheral surface of the photosensitive layer 1b of the belt photosensitive body 1 which has been previously charged by the charger 6 as a charging means. ..

On the other hand, when the scanning is started, the beam is detected by the index sensor, the modulation of the beam by the first color signal is started, and the modulated beam is on the peripheral surface of the photosensitive layer 1b of the belt photosensitive member 1. To scan. Therefore, the latent image corresponding to the first color is formed on the peripheral surface of the photosensitive layer 1b by the main scanning by the laser beam and the conveyance of the belt photosensitive member 1 by the sub-scanning. The latent image is developed by the developing device 8 in which yellow (Y) toner (visual medium) is loaded in the developing means to form a toner image on the surface of the photosensitive layer 1b. The obtained toner image passes under the blade 13A of the cleaning device 13 separated from the peripheral surface of the photosensitive layer 1b while being held on the surface of the photosensitive layer 1b, and enters the next copy cycle.

The photosensitive layer 1b is recharged by the charger 6, and then the second color signal output from the signal processing unit is input to the writing system unit 7 as in the case of the first color signal described above. Then, writing is performed on the surface of the drum to form a latent image. The latent image is developed by the developing device 9 loaded with magenta (M) toner as the second color. The magenta (M) toner image is formed in the presence of the previously formed yellow (Y) toner image,
Similarly, a cyan (C) toner image is formed by the developing device 10 having cyan (C) toner, and a black toner image is further formed on the belt surface by the developing device 11 having black toner. ..

A DC or AC bias is applied to the developing sleeves 8A, 9A, 10A, 11A of the developing units 8, 9, 10, 11 for jumping development with a two-component developer as a developing means. The development is carried out without contacting the photosensitive layer 1b whose base is grounded. As the development, non-contact development using a one-component developer can also be used.

As described above, the photosensitive layer 1b of the belt photosensitive member 1
The color toner image formed on the peripheral surface of is transferred onto the transfer paper P. The transfer papers P are sent one by one from the uppermost layer to the paper feed path 31 by the friction of the paper feed roller 30 from the paper feed cassette 29 in the cassette storage chamber 28 below the developing devices 8 to 11, and the timing roller 32 is used. Then, the image is formed on the photosensitive layer 1b of the belt photosensitive member 1 and supplied to the transfer device 12 at the same timing. As the separating means for the transfer paper P, a separating roller 33 is used.

As described above, the transfer paper P supplied to the transfer device 12 and subjected to the image transfer and the charge removal is more surely performed than the photosensitive layer 1b which suddenly changes its direction (small-diameter curvature) along the drive roller 2. After being separated and directed upward, the image is fused by the fixing roller 34, then discharged through the paper discharge roller 35 onto the paper discharge tray 36, and stacked.

On the other hand, the photosensitive layer 1 which has been transferred to the transfer paper P
In b, the conveyance is further continued, and the residual toner is removed in the cleaning device 13 in which the blade 13A and the toner conveyance roller 13B are brought into pressure contact with each other. After the cleaning is completed, the blade 13A is separated again, so that the toner conveying roller 13B removes the toner accumulated on the tip portion of the blade 13A a little later, and then the toner conveying roller 13B is separated to start a new image forming process.

Further, the tray conveying pipes 151 of the corresponding toner hoppers 38 are automatically connected to the developing devices 8, 9, 10, and 11, respectively, so that the toner is replenished.

Further, the apparatus serves as a paper feeding means for feeding the transfer paper to the paper feeding path 31, and a first paper feeding means for manually feeding paper from an openable manual feed guide plate 37 on the side of the apparatus main body. It is provided with a second paper feeding means for automatically feeding paper from the paper feeding cassette 29.

FIG. 3 is an exploded perspective view in which the image forming unit 14 and the laser writing system unit 7 described in FIGS. 1 and 2 are detached from the image forming apparatus main body 15, and an inner wall 15A provided in the image forming apparatus 15 is shown. Unit positioning holes 39, 40 are provided in the unit 7, and the unit 7 is provided with positioning pins 41, 42 which are inserted into the unit positioning holes 39, 40 and positioned at a portion facing the wall 15A.

In order to insert and position the laser writing system unit 7 in the image forming unit 14, positioning holes 43 and 44 of the laser writing unit 7 are provided in a part of the inner wall of the image forming unit 14, and the positioning is performed. Positioning pins 45 and 46 which are inserted into the holes 43 and 44 and positioned are provided in the laser writing system unit 7, and an insertion hole 47 into which the laser writing system unit 7 can be inserted is opened in the front wall of the image forming unit 14. The laser writing system unit 7 is inserted in the direction shown by the arrow in FIG. 3, and the positioning pins 45 and 46 are inserted into the positioning holes 43 and 44 in the image forming unit 14 for positioning. When the laser writing system unit 7 is inserted, it is placed and guided by the guide members 19 and 20 and positioned accurately. Further, a plurality of positioning pins 50 provided in the insertion direction are provided in a front plate member 49 provided with handles 47, 48 provided in the insertion direction of the laser writing system unit 7, and the image forming unit is provided.
The positioning pin 50 is inserted into the hole 51 provided opposite to the laser writing system unit 7 and the laser writing system unit 7 is accurately installed at a predetermined position in the image forming unit 14. The attaching / detaching direction of the image forming unit 14 is not particularly limited, and the image forming unit 14 may be attached / detached in the front-rear direction or the lateral direction.

In FIG. 4, the laser writing system unit 7 is fixed to the inner wall 15A of the image forming apparatus main body 15 with a plurality of screws 52,
On the other hand, only the image forming unit 14 is separately attached to the main body 15 of the image forming apparatus. As shown in FIG. 4, a cutout hole 47a is provided on the rear side in the insertion direction of the image forming unit 14, and the image forming unit 14 is provided with a handle 14B. , 14C, and insert into the image forming apparatus main body 15 in the direction of the arrow. At this time, the laser writing system unit 7 is inserted into the image forming unit 14 through the cutout hole 47a. Positioning pins 41 and 42 provided on the image forming unit 14 are provided on the inner wall 15A.
Insert into 39 and 40, and fix with screws as appropriate. In this way, image formation is performed with the configuration of FIG. The image forming unit 14
When the image forming unit 14 is removed to the outside, the protective cover is closed to cover the exposed portion of the belt photosensitive member 1, and when attached to the image forming apparatus main body 15, it is opened as shown in the drawing.
insert.

The embodiment shown in FIG. 5 is an image forming unit.
In this embodiment, a belt electrode is removed from the belt 14, and in this embodiment, a charger 611 is provided, which also functions as a charge for the photosensitive layer 1b of the belt photoreceptor 1 and a transfer pole for transferring the toner image onto the transfer paper P. Is a switching unit for switching between charging and transfer, and 613 is an adjusting unit for adjusting the voltage applied by charging and transfer during the switching. In the case of the present embodiment, first, the photosensitive layer 1b of the belt photosensitive member 1 is charged by the charger 611, exposed by the laser writing system unit 7 as in the embodiment of FIG. 1, and the developing sleeve 8A of the developing device 8 is used. For example, the toner is developed with yellow (Y) toner, then charged by the charger 611, exposed by the laser writing system unit 7 in the same manner as described above, and magenta (M) toner is used by using the next developing sleeve 9A. To develop. Then, sequential exposure and development are repeated to form a color image with toner on the photosensitive layer 1b, and then the recording paper P fed by the paper feed roller 30 and stopped by the timing roller 32 is started. The voltage applied to the charger 611 is switched to the transfer voltage by the voltage switching means 612, the color image is transferred onto the recording paper P by the voltage adjusted by the adjusting means 613, and the fixing roller 34 fixes the color image on the recording paper P. Then, the sheet is discharged to the outside by the sheet discharge roller 35. Finally, the photosensitive layer 1b of the belt photosensitive member 1 is cleaned by the blade 13A of the cleaning device 13.

FIG. 6 shows an image forming method for forming a color image by one rotation of the belt photosensitive member 1, that is, a one-pass system, in which the developing device 8 is provided in the image forming unit 14 and the charging device 61A is provided.
The laser writing system unit 7 is connected to the developing device 9 by a charger.
61B and laser writing system unit 7A, developing device 10 charger 61C and laser writing system unit 7B
In contrast to 11, the charger 61D and the laser writing system unit 7C are provided as a dedicated set to complete the image formation with the progress of the belt photosensitive member 1 such as charging, exposure and development. After the layer 1b has entered the charger 61A, charging, exposure and development are sequentially repeated to form on the photosensitive layer 1b of the belt photosensitive member 1 in one stroke, and the transfer paper P fed by the paper feed roller 30 is formed. After the position is adjusted by the timing roller 32, the color image is transferred by the transfer device 12. After the color image is transferred, the recording paper P is sent to the fixing roller 34 and fixed, and then discharged by the paper discharge roller 35 to the outside. The photosensitive layer 1b of the belt photosensitive member 1 is cleaned by the blade 13A of the cleaning device 13 to prepare for the next image formation.

FIG. 7 shows another embodiment of the image forming unit 14. In this embodiment, the exposure portion of the laser writing system unit 7 is formed on the upper portion as shown in the drawing, and the charger 6 is placed at the top of the image forming unit 14. At the position, and at the position of the unexposed portion in the traveling direction of the photosensitive layer 1b of the belt photosensitive member 1 from the position of the exposed portion. Then, the cleaning device 13 is connected to the developing devices 8, 9, 1
After the image formed on the photosensitive layer 1b of the belt photosensitive member 1 is transferred, the belt photosensitive member 1 is rotated approximately once and is cleaned by the blade 13A after the image is formed on the photosensitive layer 1b of the belt photosensitive member 1. With such a configuration, it is not necessary to provide the cleaning device 13 on the side of the image forming unit 14, so that the size can be reduced.

[0039]

According to the present invention, the base of the belt photosensitive member 1 is the transparent base 1a, and the photosensitive layer 1b is formed on the transparent base 1a. Therefore, the belt photosensitive member 1 is formed endlessly by exposure. It can be performed from the transparent base 1a side from the back side. Therefore, since the exposure means can be provided inside the belt photosensitive member 1, the entire image device can be made extremely small. That is, in the past, the inner side had only a member for holding the belt photosensitive member 1 in a mere space, but by incorporating the holding member and the exposing means, it can be made extremely compact. Further, according to the present invention, the exposure means, the belt photosensitive member 1, the plurality of developing devices, the cleaning device, and the strip electrodes are configured as an image forming unit, and the image forming device main body 15
Since it is configured such that they can be detached separately, the work of replacing the belt photosensitive member 1 can be easily performed.

Further, since the base of the belt photosensitive member 1 is the transparent member 1a, even if the color toner layer is formed on the photosensitive layer 1b, a good color image can be formed without being affected by the next exposure. It is possible. In addition, the entire exposure unit is formed as a laser writing system unit, which prevents dust from entering from the outside, so the optical system does not get dirty,
It can be used for a long time.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an image forming apparatus of the present invention and a partial cross-sectional view of an enlarged belt photoreceptor.

FIG. 2 is a cross-sectional view of the image forming apparatus.

FIG. 3 is an exploded perspective view of an image forming unit and a laser writing system unit.

FIG. 4 is a perspective view showing a state in which the laser writing system unit is fixed to the image forming apparatus main body and the image forming unit is removed.

FIG. 5 is a vertical sectional view showing another embodiment of the image forming apparatus of the invention.

FIG. 6 is a vertical sectional view showing another embodiment of the image forming apparatus of the invention.

FIG. 7 is a vertical sectional view showing another embodiment of the image forming unit of the present invention.

[Explanation of symbols]

 1 Belt Photosensitive Member 1a Transparent Base 1b Photosensitive Layer 6,611, 61A, 61B, 61C, 61D Charging Device 7, 7A, 7B, 7C Laser Writing System Unit 8, 9, 10, 11 Developing Device 12 Transfer Device 13 Cleaning Device 14 Image forming unit 15 Image forming apparatus main body 29 Paper feed cassette 34 Fixing roller

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Claims (7)

[Claims] 1. A belt-shaped photoreceptor having a photosensitive layer provided on a conductive substrate, and a plurality of developing devices for developing a plurality of types of electrostatic latent images formed on the belt photoreceptor. In the image forming apparatus for forming a plurality of toner images by superimposing on the belt photoconductor, the conductive substrate of the belt photoconductor is light transmissive and forms at least one of the plurality of types of electrostatic latent images. The image forming apparatus is characterized in that the image exposure is carried out through the light-transmissive conductive substrate. 2. A plurality of suspension members for endlessly forming and suspending the belt photosensitive member, and an exposing unit for exposing an electrostatic latent image to the inside of the belt photosensitive member. 1. The image forming apparatus described in 1. 3. The exposure means is fixed to the main body of the image forming apparatus, and at least the endless belt photosensitive member and a plurality of suspension members are movable from the main body of the image forming apparatus. The image forming apparatus according to item 1. 4. An image forming device, characterized in that the endless belt photosensitive member, the plurality of suspension members, and the plurality of developing devices are integrally movable with respect to the main body of the image forming device. apparatus. 5. The endless belt photosensitive member, the plurality of suspension members, the plurality of developing devices, and a belt electrode charged on the endless belt photosensitive member are configured as an image forming unit, and the image forming unit is provided. An image forming apparatus, which is movable from a main body of the forming apparatus and is integrally provided with a covering means. 6. The image forming apparatus according to claim 1, wherein the exposing unit is provided in the image forming unit and is detachable from the image forming unit. 7. The image forming unit is detached from the image forming apparatus body after the exposing unit is detached from the image forming unit.
And the image forming apparatus according to claim 6.