JPH08272278A - Color image forming device - Google Patents

Abstract

PURPOSE: To prevent an image exposing means from a damage such as a break and deformation derived from butting to an inside surface of a photoreceptor drum, by protecting the image exposing means with a protection member, in the case of attaching/detaching the image exposing means to/from the photoreceptor drum inside. CONSTITUTION: On turning a part of an actuating part while releasing from an engaging part provided on the part of a process unit 220 deg.C, protection members 102 to 105 are allowed to come in-between a base inside surface 2011 of the photoreceptor drum 201 and a light emission surface of a graded index optical transmission body array through an actuating pin by a groove cam of the protection member actuating device, the protection members 102 to 105 become in the state of protecting the light emission surface. When exposure optical systems 202 to 205 consisting of a LED array and the graded index optical transmission body array together with a supporting body are taken out of the photoreceptor drum 201 inside in this state, the device is composed so that the graded index optical transmission body array can be safely taken out without damaging the light emission surface of the graded index optical transmission body array.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer. The present invention relates to a color image forming apparatus having an image carrier and a replaceable process unit containing a charging unit, and more particularly to a protection unit for protecting the image exposure unit when the image exposure unit is attached to or detached from the image carrier.

[0002]

2. Description of the Related Art Conventionally, many methods for forming a color image using a plurality of developing devices are known. In the color image forming method as described above, as disclosed in JP-A-5-307307, the photosensitive drum is provided inside a single image bearing member (hereinafter referred to as a photosensitive drum). Exposure yellow (Y), magenta (M), cyan (C), black (B
K), a plurality of exposing means are attached, and the same number of chargers as the plurality of exposing means are provided along the outer peripheral surface of the photosensitive drum, and the electrostatic latent image formed by the charger and the exposing means is developed. A plurality of developing devices for developing the color toners of yellow (Y), magenta (M), cyan (C), and black (BK) are arranged, and a color image is formed by rotating the photosensitive drum once. A method of transferring to recording paper is known.

The plurality of exposing means comprises an LED array and a converging light transmitting body array as one set, and a plurality of supporting body portions are formed on a supporting body fixed in the photosensitive drum. The LED array provided with the converging light transmission body array is fixedly attached to the support portion, and the tip of the converging light transmission body array is exposed from the inner surface of the photosensitive drum.

[0004]

As described above, in the plurality of exposing means, the tips of the plurality of converging optical transmission body arrays are provided close to each other along the inner surface of the photosensitive drum, and the converging light is transmitted. The higher the degree of proximity between the tip light emitting portion of the transmitter array and the inner surface of the photoconductor drum, the better the light utilization efficiency can be obtained. However, when the color image forming apparatus is used for a long period of time and, for example, the image forming body or the LED array is replaced due to its use limit, the converging light transmitting body array integrated with the LED array is also supported together with the supporting member. It will be replaced by pulling it out from the photoconductor drum. At that time, as described above, since the tip light emitting portion of the converging light transmitting body array and the inner surface of the photosensitive drum are close to each other, they come into contact with each other, and in particular, the converging light transmitting body array is scratched on the inner surface of the photosensitive drum, When deformed, it is not possible to form an accurate electrostatic latent image due to a predetermined light amount fluctuation in image exposure of the damaged portion and a focus shift due to deformation. Further, the alignment of the plurality of image exposure units may be displaced due to the deformation. Therefore, the image exposing means whose tip light emitting portion is damaged or deformed as described above is discarded and a new image exposing means must be attached with high accuracy. Moreover, after the image exposing means is replaced with the supporting member, a new image exposing means must be inserted again into the photosensitive drum together with the supporting member, so that the converging light transmitting array is placed on the inner surface of the photosensitive drum even during the inserting operation. It may be scratched or deformed. In this case, since it has been inserted into the photosensitive drum, it is not possible to confirm scratches or deformation of the converging optical transmission body array. Therefore, the color image forming apparatus is operated again to check the color image on the recording paper for the first time to find the color image, so that the use of the color image forming apparatus is stopped during that time. As described above, there is a drawback in that the highly accurate and expensive image exposure means cannot be used when the LED array is attached or detached. Further, there is a defect that the inner surface of the photosensitive drum is also scratched and the image quality is deteriorated.

The present invention has been specially devised in order to remedy the abovementioned drawbacks. That is, it is a color image forming apparatus in which a plurality of image exposing means are provided in the photosensitive drum, and an image is exposed from the inner surface of the photosensitive drum to form an electrostatic latent image on the surface of the photosensitive drum. The purpose is to safely protect the image exposure means and the inner surface of the photosensitive drum when the device is detached from the photosensitive drum and replaced.

[0006]

According to the present invention, there are provided a plurality of sets of charging means and a developing means around an image carrier for forming an electrostatic latent image. In an image forming apparatus which is provided with image exposure means in the image carrier, a plurality of image exposure means provided in the image carrier, and a support member for supporting the plurality of image exposure means, The protection means for protecting the image exposure means when the supporting member is attached to and detached from the image carrier together with the plurality of image exposure means is provided. 4. An opening / closing protection member that opens and closes an exposure unit of the image exposure unit, wherein when the exposure units of the plurality of image exposure units are attached to and detached from the image carrier together with the support member, the support unit is provided. Opening / closing operation of the operating member Opening and closing, according to claim 4, the image exposing means comprises a converging optical transmission body array, and according to claim 5, the periphery of the image carrier for forming an electrostatic latent image. In an image forming apparatus in which a plurality of sets of charging means and developing means are arranged, and the image exposing means is provided in the image carrier, a plurality of image exposing means provided in the image carrier, This is achieved by having a support member that supports a plurality of image exposure units and a shielding member that shields the plurality of image exposure units in the image carrier.

[0007]

FIG. 1 is an embodiment showing a color image forming apparatus of the present invention, in which a photosensitive drum 201 formed of a transparent member coated with an OPC photosensitive member is provided in a color image forming apparatus 200.
In the photosensitive drum 201, for example, a plurality of image exposure means (hereinafter referred to as an exposure optical system) 202, 203, 204, 205 which are a combination of an LED array of light emitting elements and a converging light transmission body array (trade name SELFOC lens) are radially formed. It is formed and arranged along the inner surface 2011 of the base of the photosensitive drum 201. In the exposure optical systems 202, 203, 204, 205, image signals of respective colors read by separate image reading devices are sequentially taken out by a memory and input as electric signals to the exposure optical systems 202, 203, 204, 205, respectively. The emission wavelength of the light emitting device used in this example is in the range of 600 to 800 nm.

Further, the inner surface 2 of the base of the photosensitive drum 201
[0111] Protective members 102, 103, 10 for protecting the tip of the converging optical transmission medium array between the front end of the converging optical transmission medium array and the tip of the converging optical transmission medium array.
Provide 4,105. 206Y, 207M, 208C, 209BK are yellow (Y), magenta (M), cyan (C), and black (B
K) is a developing device containing each developer and is provided at a predetermined distance from the peripheral surface of the photosensitive drum 201. The developing device 206Y, 207M, 208C, 209BK is provided with a yellow color. (Y), magenta (M), cyan (C), and black (BK) developer replenishing means 210, 211, for replenishing each developer
212 and 213 are provided respectively. Reference numeral 214 denotes a blade-shaped cleaning device, and the waste toner after cleaning the surface of the photosensitive drum 201 by the cleaning device 241 is stored in the waste toner container 216 from the cleaning device 241 by using the conveying means 216. To configure.

Further, charging devices 300, 301, 302, 303 are provided at regular intervals on the front side of the exposure optical systems 202, 203, 204, 205 and in the vicinity of the outer side of the photosensitive drum 201 with respect to the rotation direction of the photosensitive drum 201.

Then, the photosensitive drum 201, the exposure optical systems 202, 203, 204, 205, and the developing devices 206Y, 207M, 2
08C, 209BK, developer replenishing means 210, 211, 212, 213, the cleaning device 241, and the waste toner container 216 are integrally combined as shown in the figure to form a process unit 200C, which is provided in the image forming apparatus 200. Receiving member 200D,
Place and fix the process unit 200C on 200E.

A cutout portion 200F for transferring an image from the photosensitive drum 201 to the recording paper P is formed in the lower portion of the process unit 200C, and a part of the photosensitive drum 201 is exposed. Further, a detection member S2 is fixedly provided below the process unit 200C, and a detection member S3 for detecting the detection member S2 is provided in the image forming apparatus 200. When it is placed and fixed on the 200E, the detection member S2 and the detection member S3 are detected,
The controller C1 detects attachment / detachment of the process unit 200C.

Next, an image forming process of the process unit 200C of the embodiment shown in FIG. 1 will be described. First, as an original image, an image read by an image pickup device in an image reading apparatus separate from the image forming apparatus 200 or an image edited by a computer is used as the yellow (Y), magenta (M) image. , Cyan (C), and black (B
The image signal of each color of K) is temporarily stored and stored in the memory.

When the image recording is started, the photosensitive drum 20
1 is rotationally driven to rotate in the clockwise direction, and at the same time, the charging action of the charger 300 starts application of electric charges to the photosensitive drum 201.

After the charge is applied to the photosensitive drum 201,
In the exposure optical system 202 (Y), the first color signal,
That is, image exposure is started by an electric signal corresponding to the yellow (Y) image signal, and the electrostatic latent image corresponding to the yellow (Y) image of the original image is formed on the photosensitive layer on the surface of the photosensitive drum 201 by rotational scanning. The image forms.

The electrostatic latent image is reversely developed by the developing device 206Y in a non-contact state, and the yellow (Y) toner image is formed in accordance with the rotation of the photosensitive drum 201.

Next, the photosensitive drum 201 is charged with electric charges on the yellow (Y) toner image by the charging action of the charger 301, and the color signal of the exposure optical system 203 (M), that is, the magenta ( Image exposure is performed by an electric signal corresponding to the image signal of M), and non-contact reversal development is performed by the developing device 207M so that the toner image of magenta (M) is sequentially superimposed on the toner image of yellow (Y). It is formed.

By the same image forming process as described above, the charger
302, the exposure optical system 204 (C) and the developing device 208C, and the cyan (C) toner image corresponding to the third color signal, and the last charging device 303, the exposure optical system 205 (BK), and the developing device. Black (B corresponding to the fourth color signal by 209BK
The toner images of K) are sequentially superimposed and formed, and a color toner image is formed on the peripheral surface of the photosensitive drum 201 within one rotation of the photosensitive drum 201.

As described above, in order to transfer the color toner image formed on the surface of the photosensitive drum 201 to the recording paper P by the process unit 200C, the paper feeding the recording paper P in the lower position of the image forming apparatus 200. A cassette 207 is provided, the recording paper P is fed by the paper feed roller 217, fed by the transport roller 218 to the registration roller 219, and temporarily stopped. Then, when the color toner image formed on the peripheral surface of the photosensitive drum 201 moves to the transfer position of the cutout portion 200F, the recording paper P is also fed to the transfer position.
To transfer the color toner image onto the recording paper P.
220 is transferred, and the separator 221 transfers the recording paper P to the photosensitive drum.
After separating from 201, the recording paper P is conveyed to the fixing device 223 by the conveying device 224, and the color toner image is thermally fixed on the recording paper P. The recording paper P on which the fixing is completed is conveyed by the conveying rollers 224,
The sheet is conveyed by 225, and discharged from the sheet discharge roller 226 to a sheet discharge tray 200A provided on the upper portion of the image forming apparatus 200.

2 (a) and 2 (b) are a plurality of exposure optical systems 202, 203, 204 and 205 in which a converging optical transmission medium array integrally formed with the LED array of the light emitting device of the present invention is combined, and a black plastic material, 1 shows the configuration and operating state of protective members 102, 103, 104, 105 formed of paper or a thin metal plate.

First, as shown in FIG. 2 (a), the LED array 107, 108, 1 is mounted on a support member 106 supported by a part of the process unit 200C.
The exposure optical systems 202, 203, 204, 205 in which the 09, 110 and the converging optical transmitter arrays 111, 112, 113, 114 are integrated are radially fixed using an adhesive. The exposure light emitted from each of the LED arrays 107, 108, 109, 110 is converted into the converging light transmitting array 111,
The photosensitive drum 201 is exposed through 112, 113 and 114 by the method described in FIG. On the other hand, the LED arrays 107, 108, 10
At the lateral position of 9,110, the protective member 102, 103, 104, 105 inserted between the substrate inner surface 2011 of the photosensitive drum 201 and the light emitting surface 119, 120, 121, 122 of the converging light transmission body array 111, 112, 113, 114 is provided so as to be rotatable with respect to the support member 106. . Actuating pins 115, 116, 117, 118 are provided on the protective members 102, 103, 104, 105.
Are provided integrally. On the other hand, the support member 106 is rotatably provided with a protection member actuation device 123, and the protection member actuation device 123 is
The groove cam 12 into which the operating pins 115, 116, 117, 118 are fitted.
It forms 4,125,126,127. An operating portion 128 is provided in a part of the protective member operating device 123.

As shown in FIG. 2 (a), when a part of the actuating portion 128 is engaged with an engaging portion 129 provided in a part of the process unit 200C, the groove cam 124 of the protective member actuating device 123. , 1
The protective members 102, 103, 104 and 105 are connected to the inner surface 2011 of the base of the photoconductor drum 201 and the converging light transmitting element arrays 111, 112, 113 and 114 through the operation pins 115, 116, 117 and 118 by the reference numerals 25, 126 and 127.
Of the light emitting surface 119, 120, 121, 122 of the
It is possible to sequentially perform exposure from 9,120,121,122 via the substrate inner surface 2011 of the photoconductor drum 201.

As shown in FIG. 2B, when a part of the operating portion 128 is released from a locking portion 129 provided in a part of the process unit 200C and rotated in the direction of the arrow, the protection member operating device 12
Actuating pins 115, 116, 117, by 3 groove cams 124, 125, 126, 127
The protective members 102, 103, 104 and 105 are connected via 118 to the inner surface 2011 of the base of the photoconductor drum 201 and the converging optical transmitter array 11
The protective member 102, 103, 104, 105 enters between the light emitting surfaces 119, 120, 121, 122 of the 1, 112, 113, 114 and the light emitting surfaces 119, 120, 12
It is in a state of protecting 1,122. In this state, the LED array from the inside of the photosensitive drum 201 together with the support 160
107,108,109,110 and the converging optical transmitter array 111,112,1
When the exposure optical system 202, 203, 204, 205 composed of 13,114 is taken out, it can be safely taken out without damaging the light emitting surfaces 119, 120, 121, 122 of the converging optical transmission medium arrays 111, 112, 113, 114. The protective member actuating device 123 shown in FIG.
Although not shown, in order to maintain the operating state of (1), it may be held by being forcedly rotated in one direction by a spring or the like.

FIGS. 3 (a) and 3 (b) show another embodiment of FIGS. 2 (a) and 2 (b), in which the LED array of the light emitting device of the present invention and the converging light transmitting body array are integrated. And a plurality of exposure optical systems 202, 203, 204, 205 combined with each other, and a cylindrical protection member 130.
The configuration and operating state of is shown. 2 (a) and 2 (b), the common member is indicated by common N0.

First, in FIG. 3A, the LED array 107, 1 is mounted on a supporting member 106 supported by a part of the process unit 200C.
The exposure optical system 202, 203, 204, 205 in which 08, 109, 110 and the converging optical transmission medium array 111, 112, 113, 114 are integrated and fixed radially is provided, and the exposure light emitted by each of the LED arrays 107, 108, 109, 110 is the converging optical transmission medium array 111, 112, 11
The photosensitive drum 201 is exposed through 3,114 by the method described in FIG. Meanwhile, the LED arrays 107, 108, 109, 110
The cylindrical protection member 130 is provided so as to be rotatable with respect to the support member 106 at a lateral position of the base body inner surface 2011 of the photosensitive drum 201 and the light emitting surfaces 119, 120, 121, 122 of the converging light transmission body arrays 111, 112, 113, 114. . The cylindrical protective member 130 is provided with exposure slits 131, 132, 133 and 134. On the other hand, the support member 106 is rotatably attached to the protection member operating device 1.
23 is provided, and the protection member operating member 123 and the cylindrical protection member 130 are integrally formed. An operating portion 128 is provided on a part of the cylindrical protective member operating device 1231.

As shown in FIG. 3A, when a part of the actuating portion 128 is locked to a locking portion 129 provided in a part of the process unit 200C, the exposure slit of the cylindrical protection member 130 is exposed. 131, 132, 133, and 134 are inner surfaces of the base body of the photosensitive drum 201.
And the light-exiting surfaces 119, 120, 121, 122 of the converging light-transmitting element arrays 111, 112, 113, 114 are excluded.
Since the 21,122 are opened, the inner surface 2 of the base of the photosensitive drum 201
It is possible to sequentially expose through 011.

As shown in FIG. 3 (b), in a state in which a part of the operating part 128 is released from a locking part 129 provided in a part of the process unit 200C and rotated in the arrow direction, the cylinder The exposure slits 131, 132, 133, 134 of the protective member 130 are moved to the other side, and the substrate inner surface 2011 of the photoconductor drum 201 and the light emitting surfaces 119, 120, 121, 122 of the converging light transmission body arrays 111, 112, 113, 114.
Since the space is covered with the cylindrical protection member 130, the light emitting surfaces 119, 120, 121, 122 are protected. In this state, the light emitting surfaces 119, 120, 121, 122 of the converging light transmitter arrays 111, 112, 113, 114 can be safely taken out from the photosensitive drum 201 without damaging them. In order to maintain the operating state of the cylindrical protection member operating device 1231 shown in FIG. 3 (b), it may be held by rotating it in one direction by a spring or the like, although not shown.

In FIG. 4, as shown in FIG. 2 (b), the process unit 200C releases a part of the actuating part 128 from a locking part 129 provided in a part of the process unit 200C in the direction of the arrow. It rotates together with the protective member actuating device 123, and the operation pins are driven by the groove cams 124, 125, 126, 127 of the protective member actuating device 123.
115,116,117,118 through the protection member 102,103,104,1
Reference numeral 05 denotes an inner surface 2011 of the base of the photoconductor drum 201, and light emitting surfaces 119, 120, 121, 122 of the converging light transmitter arrays 111, 112, 113, 114.
A state is shown in which the protective member 102, 103, 104, 105 is inserted in between and the light emitting surfaces 119, 120, 121, 122 are protected and withdrawn from the process unit 200C. The LED array 10
7,108,109,110 and the converging optical transmitter array 111,112,1
One end of the support member 106 provided with the exposure optical systems 202, 203, 204, 205 composed of 13, 114 is supported by the flange 300. The flange 300 is fixed to the side surface of the process unit 200C by screws 301, 302, 303, 304.
By removing 301, 302, 303, 304 from the process unit 200C, the handle 305 provided on the flange 300 allows the flange 300 to be removed.
At the same time, the support member 106 can be pulled out to the outside.
Next, for example, the LED arrays 107, 108, 109, 11 whose usage limit has come
0 is replaced, and again the support member 106 together with the flange 300 is replaced.
To the process unit 200C. Also in that case, the light emitting surface 119, 120, 121, 1 by the protective member 102, 103, 104, 105.
Of course, 22 is protected.

When the photoconductor drum 201 has been used up to the usage limit and has been replaced, the LED arrays 107, 108, 109 and 110 that have been used and the converging optical transmission body arrays 111 and 1 have been used.
The exposure optical system 202, 203, 204, 205 composed of 12,113, 114 is pulled out together with the support 106 for reuse.

By the above operation, the light emitting surface 11 of the converging light transmitting element array 111, 112, 113, 114 is removed from the photosensitive drum 201.
You can safely remove 9,120,121,122 without damaging it. Although not shown, in order to maintain the protection state of the protection member actuating device 123, it may be held by being forcedly rotated in one direction by a spring or the like.

FIG. 5 is a cross-sectional view of the process unit 200C. Bearings supported by the process unit 200C
One end of the photosensitive drum 201 is fitted and held by a cylindrical holding member 307 that is rotatably provided by 306 and is provided with a gear 308. The gear 308 is provided with a drive gear 309 for rotating the photosensitive drum 201. Further, as shown in the figure, the other end of the photosensitive drum 201 is rotatably supported via a supporting member 106 supported by the process unit 200C, a bearing 312 and a flange 310. On the other hand, as shown in FIG. 4, one end of the supporting member 106 is connected to the process unit 200.
It is integrally fixed to a flange 300 fixed to the C with screws 302 and 303, and the protection member actuating device 123 is rotatably fitted to a part of the support member 106 as shown in the drawing, and is external to the flange 300. The protection member actuating device 123 is rotated by the actuating portion 128 protruding to the protection means 102, 103, 10
4,105 can be activated.

Numerals 400 and 401 are shielding members provided at opening portions on both ends of the photosensitive drum 201. The shielding member 401 is the flange 310 of the photosensitive drum 201 and the LED arrays 107, 108, and 108, as described above.
The converging optical transmitter array 111, 112, 11 integrated with 109, 110
Between 3 and 114, it is provided so as to be in close contact with the inner surface 2011 of the base of the photosensitive drum 201, and is also in close contact with a part of the support member 106,
Prevents dust from entering from the outside. On the other hand, the shielding member 400 is also provided at the opening at the other end of the photosensitive drum 201. The shielding member 400 is also provided so as to be in close contact with the inner surface 2011 of the base of the photosensitive drum 201, and the protection member operating device 123
It is also installed in close contact with and prevents dust from entering from outside. In this way, the converging optical transmitter array 111, 112,
Both ends of 113, 114 are completely shielded by the shielding members 400, 401, and in particular, the converging optical transmitter array 111, 112, 113,
The light emitting surfaces 119, 120, 121, 122 of 114 are not dirty.

The photoconductor used for the photoconductor drum 201 often has a light-transmitting property. In this case, in order to prevent reflection of image exposure light or light leakage from the outside, It is preferable that the inner surface side of the shielding members 400 and 401 facing the photoconductor be black.

Further, as the light emitting body for the image exposure, the LED arrays 107, 108, 109, 110 can be mentioned, but more recently, the image exposure means can be used.

(1) Exposure system in which light-emitting elements are arranged in a line in an array Fluorescent material (fluorescent tube): FL electroluminescence: EL plasma discharge: PL (2) Elements having an optical shutter function are arranged in a line Exposure system Magneto-optical effect shutter array: LISA Translucent piezoelectric element shutter array: PLZT Liquid crystal shutter array: LCS

[0035]

As described above, the present invention provides claim 1.
Alternatively, in the photosensitive drum, a plurality of image exposing means are built in, and when the image exposing means is detached from the photosensitive drum, the image exposing means is protected by a protective member. The image exposing means does not come into contact with the inner surface of the photoconductor drum and is not damaged or deformed to be damaged, and the highly accurate and expensive image exposing means can be used for a long period of time.

In the present invention, the protective member is located near the inner surface of the image exposing means or the image forming member and can be opened and closed. Therefore, the protective member can be easily and quickly moved. Can be done.

According to a third aspect of the present invention, the opening / closing operation of the protective member is provided on a supporting member for supporting the image exposing means, the opening / closing operation of the exposing means is reliable, and the image exposing means is processed together with the supporting member. When detaching from or replacing the unit, it is possible to reliably hold the closing operation.

In the present invention, the image exposure means provided in the photosensitive drum is shielded by the shielding member to prevent the ingress of dust. Therefore, dust is prevented to prevent light emission of the image exposure means which is the exposure means. It became possible to keep a good image for a long time without wearing it.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an image forming apparatus of the present invention.

FIG. 2 is a configuration diagram showing a protection unit and an operation for protecting the exposure unit of the present invention.

FIG. 3 is a configuration diagram showing another protection means and an operation for protecting the exposure means of the present invention.

FIG. 4 is a perspective view showing a state in which an exposure unit is taken out from the image carrier of the present invention.

FIG. 5 is a cross-sectional view showing a process unit of the present invention.

[Explanation of symbols]

 102,103,104,105 Protective member 106 Supporting member 107,108,109,110 LED array 111,112,113,114 Focusing light transmitter array 119,120,121,122 Light emitting surface 123,1231 Protective member operating device 130 Cylindrical protective member 200 Color image forming device 200C process unit 201 Photosensitive drum 300,301,302,303 Charger

Claims (5)

[Claims] 1. An image forming apparatus in which a plurality of sets of charging means and developing means are arranged around an image carrier for forming an electrostatic latent image, and image exposing means is provided in the image carrier. When a plurality of image exposing means provided in the image bearing body, a supporting member for supporting the plurality of image exposing means, and the supporting member together with the plurality of image exposing means are attached to and detached from the image bearing body A color image forming apparatus comprising: a protection unit that protects the image exposure unit. 2. The color image forming apparatus according to claim 1, wherein the protection unit is an opening / closing protection member that opens / closes an exposure unit of the plurality of image exposure units. 3. The opening / closing protection member is opened / closed by opening / closing an operation member provided on the support member when the exposure units of a plurality of image exposure units are attached / detached together with the support member in / from the image carrier. The color image forming apparatus according to claim 1. 4. The color image forming apparatus according to claim 1, wherein the image exposing unit is composed of a converging light transmitting element array. 5. An image forming apparatus comprising a plurality of sets of charging means and a developing means arranged around an image carrier for forming an electrostatic latent image, and an image exposing means provided in the image carrier. In the image carrier, there are provided a plurality of image exposure means, a support member for supporting the plurality of image exposure means, and a shield member for shielding the plurality of image exposure means in the image carrier. A color image forming apparatus characterized by the above.