JPH08202155A - Color image forming device - Google Patents

Abstract

PURPOSE: To provide a color image forming device capable of making the forming speed of a color image fast by superimposing different color toner images in one rotation of a drum-like image forming body and further, preventing a deterioration of image quality, with a comparatively compact and inexpensive constitution. CONSTITUTION: In the color image forming device constituted in such a manner that plural groups of electrifiers 3Y-3K, image exposure means 4Y-4K for executing an image exposure constituted with dots, developing units 5Y-5K sticking toner to the face of the image forming body 1 and a cleaner are arranged on the outer periphery of the drum-like image forming body 1, to superimpose the different color toner images on the periphery of the rotating image forming body 1, the plural electrifiers 3Y-3K and image exposure means 4Y-4K and the cleaner 2 are disposed in a unit frame 30 holding the bearing of the image forming body 1 on both ends and rotatably supporting the image forming body 1 inside and the unit frame 30 is moved in the axial direction of the image forming body 1, to be attached to/detached from a device main body in a state where the plural developing units 5Y-5K or toner supplying means 50Y-50K are retreated from arrangement positions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of sets of a charging device, an image exposing means for injecting image exposure of dot construction, and a developing device for adhering toner to the surface of the image forming body on the outer periphery of a drum-like image forming body. And a cleaner, and relates to a color image forming apparatus for superimposing a different color toner image on the peripheral surface of the rotating image forming body.

[0002]

2. Description of the Related Art A color image forming apparatus as described above has a color image forming speed higher than that of a color image forming apparatus in which a toner image is formed on the image forming body for each rotation of the image forming body and superposed. However, not only does it cost more because it requires multiple sets of chargers and image exposure means, it is not only large in size, but it also deteriorates image quality due to color image misregistration and poor maintainability. There was a problem to say.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and the different color toner images are superposed within one rotation of the drum-shaped image forming body to form a color image. It is an object of the present invention to provide a color image forming apparatus which has a high forming speed, can prevent the image quality from being deteriorated, and has a relatively small size which is excellent in maintainability and can be constructed at low cost.

[0004]

SUMMARY OF THE INVENTION The present invention is a set of a charging device, an image exposing means for injecting image exposure having a dot structure and a developing device for adhering toner to the surface of the image forming body. In a color image forming apparatus in which a plurality of sets and a cleaner are provided and different color toner images are superimposed on the peripheral surface of the rotating image forming body, the bearings of the image forming body are held at both ends to form an image inside. The plurality of chargers, the image exposure means, and the cleaner are arranged in a unit frame that rotatably supports the body, and the unit frame is installed in a state in which the plurality of developing devices are retracted from their arranged positions. The image forming body is moved in the axial direction with respect to the main body so as to be detachable, or a plurality of sets of the charger, the image exposing means, the developing device, and the cleaner are arranged in the unit frame. Equipment With the configuration, characterized in that the unit frame and detachable by moving in the axial direction of said image forming body to the body, to achieve the above object.

[0005]

Operation: That is, a charger is provided on the outer periphery of the drum-shaped image forming body,
In the image forming apparatus of the present invention in which a plurality of sets of the image exposing unit and the developing unit are arranged and the color image forming speed is high, the image exposing unit is arranged in a unit frame which is detachable from the main body of the apparatus while supporting the image forming body. The image exposure means is provided for the image forming body so that the position where the image exposure of each image exposing means enters the image forming body does not change and the phase angle between these positions is accurately determined. Therefore, by shifting the timing of image exposure according to the phase angle, it is possible to form a color image with good image quality without color shift on the image forming body. In addition to the arrangement of a cleaner and a charger in the unit frame, it is easy to assemble, maintain, and replace the image forming body and the image forming means around the image forming body. It is also easy to construct, and thus the entire device can be constructed at a relatively low cost and in a small size.

[0006]

The present invention will be described below with reference to the illustrated examples.

FIGS. 1, 4 and 7 are schematic sectional views showing an example of the color image forming apparatus of the present invention, and FIGS. 2 and 5 support the image forming member of the apparatus of FIGS. 1 and 4, respectively. A partial side sectional view showing a state in which the unit frame is attached to the apparatus main body, and FIGS. 3 and 6 are sectional views showing a state after removing the detachable unit frame and the like from the apparatus main body of the apparatus of FIGS. Is.

In the color image forming apparatus shown in FIGS. 1, 4 and 7, the image information of the original document read by the image pickup device by the image reading device or the image information edited by the computer is converted into yellow by the image signal processing circuit. Y), magenta (M), cyan (C), and black (K) separated color image signals are temporarily stored in a memory, and a color image is formed based on the image signals from the memory. The color image forming process is performed as described above.

When the start of image formation is instructed, a drum-shaped image forming body 1 having a photoconductor surface layer such as OPC is rotated in the clockwise direction under the control of a control device (not shown), and its peripheral surface is cleaned. 2 is cleaned, and then the charger 3Y using a corona discharger is uniformly charged. The image exposure means 4Y makes image exposure on the charged surface based on the Y image signal input from the memory to form an electrostatic image of a dot structure. The electrostatic image is ejected from the non-contact two-component or one-component developer layer formed on the developing roller by the toner charged to the same polarity as that of the electrostatic image, and adhered to the electrostatic image by the developing device 5Y. It is developed into a toner image.

The Y toner image forming surface is uniformly charged by the charging device 3M again, and the image exposing means 4M similarly makes an image exposure based on the image signal of M on the uniformly charging surface to make the M static image. Form an electric image. The electrostatic image is similarly developed into an M toner image by the developing device 5M, thereby forming a two-color image formed on the peripheral surface of the image forming body 1 by superposition with the Y toner image previously formed.

Similarly, a C toner image is formed on the two-color image forming surface by the charging device 3C, the image exposing means 4C and the developing device 5C,
Further, a K toner image is sequentially superposed by the charging device 3K, the image exposing means 4K and the developing device 5K to form an image forming body 1.
Within one rotation, a color image is formed on the peripheral surface by superimposing four color toner images.

In the image forming apparatus shown in FIGS. 1 and 4, the image exposing means 4Y to 4K are provided with a large number of LEs in a direction parallel to the axis of the image forming body 1.
While an LED array consisting of arrayed LEDs in which Ds are arrayed and a SELFOC lens as a unity magnification image forming element is used, the image forming apparatus of FIG. 7 uses a semiconductor laser for the image exposure means 4Y-4K. A laser beam scanner including a polygon mirror, an fθ lens, and a cylindrical lens is used.

The color image formed on the peripheral surface of the image forming body 1 is fed from the lower paper feed cassette 6 via the friction feed roller 7 and the pressure conveying roller 8 or from the manual feed guide 9 side to the feed roller 10. Alternatively, unlike the image forming apparatus of FIG. 1 having only the single-sided mode, the double-sided mode of the image forming apparatus of FIG. 4 and FIG. 7 can be employed. Further, in the double-sided mode of the image forming apparatus of FIG. It is transferred by the transfer device 12 using a corona discharger to the transfer paper fed by the timing roller 11 via the.

The transfer paper on which the color image has been transferred is then transferred to the image forming body 1 by the separator 13 using a corona discharger.
Separated from the sheet, conveyed by a conveyor 14 having a suction means, and fixed with a color image by a fixing device 15 using a fixing roller, and then discharged out of the machine by a pinching conveying roller of a discharge path 17, or In the double-sided mode of the image forming apparatus of FIGS. 4 and 7, when the back side is not transferred, the discharge path 17
Reverse rotation of the pinching and conveying roller 8 and the fixing roller and the conveyor 14
By the rotational displacement to the position indicated by the two-dot chain line and the conveyance by the nip conveying roller 8 in the reverse feeding path 16, the sheet is again sent to the transfer position via the timing roller 11 and the color image is transferred to the back surface. The color image is fixed by the fixing device 15 and then discharged outside the apparatus.

On the other hand, the peripheral surface of the image forming body 1 on which the color image is transferred is cleaned of the residual toner by the cleaner 2 and is provided for the next color image forming step.

In any of the above color image forming apparatuses, the apparatus main body 20 has a transfer paper transport path from the mounting portion of the paper feed cassette 6 to a position where it exits the fixing device 15 or the lower half of the manual transfer paper transport path. A lower frame 21, a lower frame 21 that rotates counterclockwise with respect to the lower frame 21 with the upper roller shaft of the pinching and conveying roller 8 that exits the fixing device 15 as a rotation axis; A discharge path cover 23 that opens in the discharge path 17 by rotating counterclockwise by a hinge provided above the insertion slot of the paper feed cassette 6 of 21, and a counterclockwise opening function that also serves as a discharge tray for the transfer paper. It consists of a movable top cover 24. Thus, when a jam occurs in the discharge path 17, the jammed paper can be easily removed by opening the discharge path cover 23, and when a jam occurs in the transport path up to the discharge path 17, the upper frame 22 is further opened. Jam paper can be easily removed by rotating. Not limited to this, hinges are provided on both sides of the manual feed port so that the upper frame 22 can be opened and rotated in the clockwise direction with respect to the lower frame 21, and the discharge path cover 23 can be used as an upper roller of the pinching conveyance roller at the outlet to the discharge tray. It is also possible to rotate the shaft in the clockwise direction with the shaft as the rotation shaft to open the discharge path 17. Thereby, the upper frame 22 can be opened and rotated independently of the discharge path cover 23.

Further, by opening and rotating the upper cover 24, the toner replenishing container support guide 5a provided on the developing devices 5Y to 5K as shown in FIGS. 1 and 7 and the toner supply container supporting guide 5a shown in FIGS. Toner supply container support guide provided on the upper frame 22
The toner replenishing containers 50Y to 50K supported by 22a are used alone or in the image forming apparatus of FIGS.
The developing devices 5M and 5C supported by the developing device support guide 22b as shown in FIG.
Can be taken out. 3 and 6 show the apparatus main body 20.
7 shows a state of the apparatus main body 20 after taking out the toner supply containers 50Y to 50K and the developing devices 5Y to 5K together with a unit frame 30 described later.

The toner replenishing containers 50Y-5 shown in FIGS.
At 0K, the outlet for dropping the toner across the width of the lower developing device is closed by the toner replenishing roller, and there is almost no risk of toner spilling unless the toner replenishing roller rotates. On the other hand, the toner supply container 50 of FIG.
For Y to 50K, the toner is fed to the drop tube 50a outside the side wall by the toner conveying screw on the lower side and the receiving tube 5b of the developing device 5Y to 5K is supplied.
When the connection between the drop tube 50a and the receiving tube 5b is separated by removing the unit frame 30 to the outside of the apparatus main body 20 as described later, the toner is likely to spill from the drop tube 50a. Therefore, as shown in FIG. 5, a slide door 50b is provided at the lower part of the drop tube 50a to close the drop tube 50a by a spring force when the connection with the receiving tube 5b is separated.

The unit frame 30 allows the image forming body 1 and the image forming means around the image forming body 1 to be incorporated with a high relative positional accuracy, and in order to enhance the strength, the unit frame 30 is shown in FIGS.
As shown in FIG. 7, it has a substantially cylindrical shape, and as shown in FIGS. 2 and 5, bearings 32 of the image forming body 1 are held at both ends to rotatably support the image forming body 1 inside. 1, FIG. 4, FIG. 7, and FIG. 7 by means of a unit frame support guide 22c provided on the upper frame 22 as shown in FIG.
It can be attached to and detached from the upper frame 22 by being guided in the direction perpendicular to the paper surface of FIG.

When the unit frame 30 is attached to or detached from the upper frame 22, the transfer unit 12, the separator 13, the conveyor 14, etc., which are provided on the lower frame 21 and are close to the image forming body 1, are attached to the unit frame.
Since it interferes with 30, the upper frame 22 is opened and rotated with respect to the lower frame 21 in any image forming apparatus, and the unit frame 30 is placed in a state of being separated from the transfer device 12 or the like. Alternatively, in the image forming apparatus of FIG. 1, the transfer device 12 integrally connected and the transport path lower guide and separator 13 in front of the transfer device 12 are provided.
In addition, the conveyor 14 is rotated clockwise about the drive roller shaft on the fixing device 15 side of the conveyor 14 to the two-dot chain line position in FIG. 1, that is, the solid line position in FIG. It is necessary to keep it away from. In addition, like the color image forming apparatus of FIGS. 1 and 7, the developing devices 5Y to 5K
Is disposed on the upper frame 22 side so as to be slidably displaceable by the developing device support guide 22b and approaches the image forming body 1 through a peep hole provided on the peripheral wall of the unit frame 30, the developing device is further attached when the unit frame 30 is attached or detached. Since 5Y to 5K also interfere with each other, it is necessary to retract the developing devices 5Y to 5K according to the developing device support guide 22b outside the unit frame 30 or to remove them from the upper frame 22 in advance.

As described above, the unit frame 30 is the device main body.
When it is taken out of the outside 20, the opening of the peripheral wall of the unit frame 30 that has brought the transfer device 12 and the like close to the image forming body 1 opens greatly,
Since the image forming body 1 is easily damaged or deteriorated, the unit frame 30 is provided with an opening / closing door 31a for closing the opening. 1 and 4 show a state in which the opening / closing door 31a is rotated and opened and held by a holding spring, and FIG. 7 shows the opening / closing door 31a.
Shows a state in which the spring has been urged to open and rotated until it hits the stopper. Further, in the unit frame 30 of FIGS. 1 and 7, since the peep holes of the developing devices 5Y to 5K are also opened, the opening / closing door 31b for closing the opening is also provided in the unit frame 30. In this respect, the unit frame 30 of FIG. 4 is the developing device 5Y-5K.
Even if the unit frame 30 is taken out of the apparatus main body 20, the peephole does not open unlike the unit frame 30 of FIGS. 1 and 7, but the developing devices 5Y to 5K are connected to the unit frame 30. Since it is inserted from the outside to the inside and attached to the unit frame 30, an opening / closing door 31c is provided at the entrance. The same applies to the arrangement of the chargers 3Y to 3K, and the opening / closing door 31d is provided. In addition, all the unit frames 30 are image exposure means.
Although 4Y to 4K are inserted from the outside and attached, an opening / closing door that closes the installation hole when removed is not shown but is preferably provided in the same manner.

The above-mentioned developing devices 5Y to 5K and charging devices 3Y to 3K
Alternatively, it is convenient that the opening / closing doors for the image exposure units 4Y to 4K are biased by a spring in the closing direction so that they can be naturally closed when the developing device or the like is taken out. Further, although the cost is high and the unit frame 30 and further the image forming apparatus tends to be large, the opening / closing door is provided as a door that slides in the circumferential direction on the inner surface side of the peripheral wall of the unit frame 30 and is electrically driven by a small motor or the like. It goes without saying that it is possible to automatically open and close by interlocking with the attachment / detachment of the developing device or the like or the attachment / detachment of the unit frame 30. These opening / closing doors also play the same role as the opening / closing doors 31a and 31b when the developing device or the like is taken out from the unit frame 30.

Further referring to FIGS. 2 and 5, the unit frame
A structure incorporating 30 image forming bodies 1 and the like and a mounting structure to the upper frame 22 will be described in detail.

2 and 5, the image forming body 1 includes a photosensitive drum 1b having a driven gear 1a formed on the outer periphery on the front end side in the direction of insertion into the unit frame 30, and a mirror member 1c on the front and rear ends. ， 1d,
The imager shaft 1e and the nut 1f that integrally combine them.
And an optional tightening screw 1g for connecting the photosensitive drum 1b and the mirror members 1c, 1d. The unit frame 30 has at least image exposure means 4Y to 4K that have a great influence on the image quality, lightweight and small chargers 3Y to 3K, and a cleaner 2 that can be made compact by not accumulating toner with only one unit. And a peripheral wall body 31 for arranging, and mirror members 33, 34 and mirror members 33, 34 on the front and rear ends for holding the bearings 32, respectively.
A male screw nut 35 that is screwed onto and stops the bearing 32 from coming out.
And a tightening screw 36 for connecting the peripheral wall body 31 and the mirror members 33, 34.
And a nut 37 that is screwed to the rear end side of the image forming body shaft 1e and tightens the inner race of the bearing 32 on the rear end side between the flange end surface of the image forming body shaft 1e and is internally assembled. The image forming body 1 is rotatably supported. The unit frame
One of the male screw nut 35 screwed to the mirror member 34 of the 30 or the nut 37 screwed to the rear end side of the image forming body shaft 1e can be omitted.

Since the unit frame 30 has the above-mentioned structure, not only the position where the image exposing means 4Y to 4K are arranged with respect to the image forming body 1 becomes constant, but also the mirror member which is concentric with the image forming body axis 1e. By forming the image exposure means 4Y to 4K in the peripheral wall body 31 by a known means such as an allocation based on the outer circumference of the bearing holes of 33, 34 or the bearing holding portion protruding to the outside as an index. It can be easily provided so that the mutual positional phase with respect to the body 1 is accurately determined. Therefore, in the color image forming apparatus of FIGS. 1, 4 and 7 using this unit frame 30, the timing of the image exposure of the image exposing means 4Y to 4K, that is, the image signals of Y to K from the image signal memory are detected. By shifting the reading timing in accordance with the position phase of the image exposure units 4Y to 4K, it is possible to form a color image with good image quality without color misregistration.

In the unit frame 30 of the illustrated example, the mirror members 33 and 34 project the bearing holding portions to the outside. Therefore, the unit frame 30 is provided with a front plate 38 that is fitted to the outer periphery of the bearing holding portion projecting to the outside of the mirror member 34 and is integrally coupled to the mirror member 34 at the rear end side in the insertion direction into the upper frame 22. The unit frame 30 can be attached to and detached from the upper frame 22 by holding a handle (not shown) provided on the front plate 38. The unit frame 30 is fed into the upper frame 22 according to the unit frame support guide 22c, and the front plate 38 is moved to the upper frame 2.
The unit frame 30 is mounted by connecting it to 2 with screws, etc., and thereby the drive gear supported on the upper frame 22 side.
22d meshes with the driven gear 1a of the image forming body 1 to rotate the image forming body 1 or the like.

As described above, the image forming body 1 and the image exposing means 4Y
Since it is possible to easily attach and detach the unit frame 30 assembled with ~ 4K, etc. to the apparatus main body 20, it is possible to easily replace the toner replenishing containers 50Y to 50K, that is, replenish toner to the developing devices 5Y to 5K.
The developing devices 5Y to 5K can be downsized, and the image forming apparatus can be downsized and relatively inexpensive.

Therefore, the peripheral wall body 31 of the unit frame 30 shown in FIG.
As shown in FIG. 4, developing devices 5Y to 5K are also arranged.
In the drawing, a receiving tube 5b of the developing devices 5Y to 5K connected to the drop pipe 50a of the toner supply containers 50Y to 50K and a conveying screw 5c for carrying the toner into the developing devices 5Y to 5K are shown. At the lower end of the drop pipe 50a, there is provided a slide door 50b which is displaced to the open position against the spring bias by an opening / closing cam 5d which is integrally provided on the upper part of the receiving pipe 5b. Even if the unit frame 30 is pulled out to the left in FIG.
Even if the toner supply containers 50Y to 50K are pulled upward, the action on the slide door 50b is released and the slide door 50b is closed by the spring bias. The connection structure between the toner supply containers 50Y to 50K and the developing devices 5Y to 5K is the same as the connection structure between the cleaner 2 and the waste toner container 18, which will be described later.

On the other hand, in the unit frame 30 of FIG. 2, as shown in FIG. 1 or 7, the developing devices 5Y to 5K are provided on the peripheral wall body 31 with spacer rollers provided at both ends of the developing roller. A peephole 31e for contacting the non-image area of the section is provided, and the developing devices 5Y to 5K are not provided. Developer 5Y-5K
As described above, is supported by the developing device support guide 22b provided on the upper frame 22 so as to be slidable. It must be slid and retracted at least to the position where the developing roller comes off the peripheral wall body 31.

The cleaner 2 incorporated in the unit frame 30 shown in FIG. 1 and FIG. 2, FIG. 4 and FIG. 5 or FIG. 7 sequentially sends the toner to the dropping pipe outside the side wall by the lower conveying screw to lower the frame 21. The waste toner container 18 is designed to be dropped into the receiving tube of the waste toner container 18 arranged in the above. There is. The removal of the waste toner container 18 is performed by pulling out the unit frame 30 and then pulling it out in the same manner as the unit frame 30. Therefore, the opening / closing cam that acts on the slide door provided at the lower end of the toner dropping tube of the cleaner 2 is provided on the lower frame 21 and is not provided on the receiving tube of the waste toner container 18, as described above. Supply container 50Y to 50K and developing unit 5Y
Different from the connection structure between ~ 5K.

[0031]

According to the color image forming apparatus of the present invention, the color image is formed within one rotation of the drum-shaped image forming body, so that not only the color image forming speed is high but also the image forming body is supported. Since the image exposure means is disposed in the detachable unit frame of the apparatus main body, the position where the image exposure of each image exposure means is incident on the image forming body does not change, and the phase angle between these positions is accurate. As described above, it is easy to dispose the image exposure means on the image forming body, and therefore, by shifting the timing of the image exposure according to the phase angle, it is possible to obtain good image quality without color shift on the image forming body. It is possible to form a color image and, in combination with disposing a cleaner and a charger on the unit frame, facilitate assembly, maintenance and replacement of the image forming body and the image forming means around it. Therefore, the area around the image forming body can be made compact. It can also readily be, therefore it is possible to configure the entire apparatus compact in a relatively low cost. Further, in a mode in which the unit frame is provided with a peephole for the developing device, an opening / closing door for the charging device, an opening for arranging the image exposure means, etc., the unit frame is taken out of the apparatus main body, The image forming body will not be damaged or deteriorated by the opening of the peep hole or the arrangement hole when the exposing means or the like is taken out.

[Brief description of drawings]

FIG. 1 is a schematic configuration sectional view showing an example of a color image forming apparatus of the present invention.

FIG. 2 is a partial side cross-sectional view showing a state where the unit frame of the apparatus of FIG. 1 is attached to the apparatus body.

3 is a cross-sectional view showing a state after removing a detachable unit frame and the like from the apparatus body of the apparatus of FIG.

FIG. 4 is a schematic configuration sectional view showing another example of the color image forming apparatus of the present invention.

5 is a partial side cross-sectional view showing a state where the unit frame of the apparatus of FIG. 4 is attached to the apparatus main body.

6 is a cross-sectional view showing a state after removing a detachable unit frame and the like from the apparatus body of the apparatus of FIG.

FIG. 7 is a schematic configuration sectional view showing another example of the color image forming apparatus of the present invention.

[Explanation of symbols]

 1 image forming body 2 cleaner 3Y, 3M, 3C, 3K charger 4Y, 4M, 4C, 4K image exposure means 5Y, 5M, 5C, 5K developing device 50Y, 50M, 50C, 50K toner supply container 6 paper feed cassette 12 transfer Device 15 Fixing device 20 Device body 21 Lower frame 22 Upper frame 22a Toner supply container support guide 22b Developer support guide 22c Unit frame support guide 24 Upper cover 30 Unit frame 31 Peripheral wall body 31a, 31b, 31c, 31d Open / close door 31e Peep hole

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G03G 15/01 111 Z 112 112 A

Claims (10)

[Claims] 1. A cleaner is provided on the outer periphery of a drum-shaped image forming body, a plurality of sets of a charging device, an image exposing means for injecting image exposure of dot construction, and a developing device for adhering toner to the surface of the image forming body, and a cleaner. In a color image forming apparatus, in which a different color toner image is superposed on the peripheral surface of the rotating image forming body, a unit that holds the bearings of the image forming body at both ends and rotatably supports the image forming body The plurality of chargers, the image exposing means, and the cleaner are arranged in a frame, and the unit frame is attached to the apparatus main body of the image forming body with the plurality of developing devices retracted from their positions. A color image forming apparatus characterized by being detachable by moving in the axial direction. 2. The color image forming apparatus according to claim 1, wherein a protective cover that opens and closes a peep hole of the developing device is provided on a peripheral wall of the unit frame. 3. A protective cover provided on the peripheral wall of the unit frame for opening and closing a peep hole of a developing device closes the peep hole by releasing a locking spring when the unit frame is pulled out of the apparatus main body. The color image forming apparatus according to claim 2. 4. A cleaner and a set of a set comprising a charger, an image exposing means for injecting image exposure of dot construction, and a developing device for adhering toner to the surface of the image forming body are provided on the outer periphery of the drum image forming body. In a color image forming apparatus, in which a different color toner image is superposed on the peripheral surface of the rotating image forming body, a unit that holds the bearings of the image forming body at both ends and rotatably supports the image forming body A plurality of sets of the charging device, the image exposing unit, the developing device, and the cleaner are arranged in the frame, and the unit frame is moved in the axial direction of the image forming body with respect to the apparatus main body so that the unit frame can be attached and detached. Characteristic color image forming apparatus. 5. A plurality of toner replenishing means are provided in the main body of the apparatus, and the plurality of developing devices and the toner replenishing means are brought into contact with and separated from each other when the unit frame is attached and detached.
The color image forming apparatus described in 1. 6. The color image forming apparatus according to claim 1, wherein the image exposing unit is an array of light emitting elements in a direction parallel to an axis of the image forming body. . 7. The color image forming apparatus according to claim 1, wherein the image exposing unit is a laser beam scanner. 8. The unit frame has circular holes centered on the axial center of the image forming body on the outer surfaces of both ends holding the bearing, or a circumferential surface centering on the axial center of the image forming body. The color image forming apparatus according to any one of claims 1 to 7, characterized in that a projecting portion having an outer peripheral surface is formed. 9. The color image forming apparatus according to claim 7, wherein a protective cover is provided on the peripheral wall of the unit frame to open and close the installation hole of the image exposure unit. 10. A protective cover provided on a peripheral wall of the unit frame for opening and closing a mounting hole for the image exposing means closes the mounting hole by removing the image exposing means from the peripheral wall. 9. The color image forming apparatus according to item 9.