JP3379039B2 - Image forming device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, printer, F
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as an AX that forms an image by arranging a charging unit, an image exposing unit, and a developing unit on the peripheral surface of a belt-shaped image forming unit, and particularly relates to the periphery of the image forming unit. The present invention relates to an electrophotographic color image forming apparatus in which a plurality of charging means, image exposing means and developing means are arranged on the surface and a toner image is superposed during one rotation of an image forming body to form a color image.

[0002]

2. Description of the Related Art Conventionally, as one of methods for forming a multicolor image, a color image is formed by sequentially performing charging, image exposure and development for each color within one rotation of a photosensitive member which is an image forming member. There is known a color image forming apparatus for forming an image.

However, although the above-mentioned color image forming apparatus enables high-speed image formation as a method for forming a multicolored color image, a charging device, an image exposing means and a developing device are provided within one circumference of the photosensitive member. It is necessary to dispose a plurality of sets, and the image exposure optical system may be contaminated by toner leaking from the developing device in the vicinity, which may impair the image quality. To avoid this, it is necessary to increase the distance between the image exposing means and the developing device. Therefore, there is a contradiction that the diameter of the photoconductor is inevitably increased and the device is enlarged. For the purpose of avoiding this drawback, the substrate of the image forming body is formed of a transparent material, and a plurality of image exposing means are housed therein, and the image is exposed through the substrate to the photosensitive layer formed on the outer periphery thereof. An apparatus of the form is proposed, for example, by Japanese Patent Laid-Open No. 5-307307.

[0004]

However, in the apparatus according to the above-mentioned proposal, the structure is complicated because a large number of image exposing means are arranged inside the image forming body, and a lot of chargers and developing devices are arranged outside the image forming body. It is difficult to attach and detach the formed body and the image exposure means, which makes the handling difficult, and it is difficult to maintain the positional accuracy between the respective devices. In particular, it is difficult to dispose the image forming body or to attach and detach the image forming body and the image exposing means by disposing the fixed optical system inside.

In the above-mentioned image forming apparatus using a belt photosensitive member as an image forming member, the belt photosensitive member is located between the image exposing unit provided inside the belt photosensitive member and the belt photosensitive member. A structure is used in which a transparent member that prevents the body from floating is provided, and the belt photosensitive member is supported by the transparent member. However, the toner that wraps around from the end portion of the belt photosensitive member is caught between the belt photosensitive member and the transparent member. When the belt photosensitive member and the transparent member are rubbed into each other and rubbed against each other, surface or dot-like toner stains are generated, which stains the transparent member, resulting in poor image forming optical system and uneven image exposure and image streaks. And so on, a good image cannot be obtained.

Further, in the image forming apparatus in which the image exposing means is arranged inside the belt photosensitive body which is the image forming body, the distance between the exposure optical system which is the image exposing means and the belt photosensitive body is highly accurate. Need to be positioned and maintained at the position where the exposure optical system and the image forming body are positioned, and the belt floats, the resist for image exposure and the image forming position change, and good latent image formation is obtained. The problem of disappearing arises.

The present invention solves this problem and improves the result.
First, to provide a transparent member that prevents contamination, and secondly to provide a highly accurate positioning means between the exposure optical system and the belt photosensitive member that does not cause the belt to float, and maintain the positional relationship between them. It is an object of the present invention to provide an image forming apparatus capable of obtaining a good image, and further an object of the present invention is to provide a color image forming apparatus capable of obtaining a good color image by superposing toner images.

[0008]

The above-mentioned object is to provide a belt-shaped image forming body for forming a latent image and an image exposing means inside the belt-like image forming body, and the belt-shaped image forming means is provided by the image exposing means. In an image forming apparatus in which image exposure is performed from the back surface of the image forming body, the belt-shaped image forming body and the image exposing means are in contact with the belt-shaped image forming body and are transparently formed to transmit the image exposing light. This is achieved by an image forming apparatus characterized in that a transparent member having a convex portion is arranged outside the area (first invention).

The above-mentioned object is to provide a belt-shaped image forming body for forming a latent image and an image exposing means inside the belt-like image forming body, so that the image exposing means allows the back surface of the belt-shaped image forming body to be exposed. in the image forming apparatus in which the image exposure is performed, a transparent member formed on a light-transmitting contact with the belt-shaped image forming body between said image exposing means and the belt-shaped image forming body, before
This is achieved by an image forming apparatus characterized in that the transparent member is provided with a cleaning means (second invention).

The above-mentioned object is to provide a belt-shaped image forming body for forming a latent image and a plurality of image exposing means inside the belt-shaped image forming body, and to form the belt-like image forming body by the plurality of image exposing means. In the image forming apparatus in which the image exposure is performed from the back surface of the image forming apparatus, a holding member that holds the plurality of image exposing units, a pressing unit that presses the holding members, a belt-shaped image forming body and the image exposing unit are provided. said provided a transparent transparent member in contact with the belt-shaped image forming body, and said transparent member and said image exposure means and said holding member integrally coupled, said transparent the belt-shaped image forming body by the pressing means This is achieved by an image forming apparatus characterized by pressing through a member (third invention).

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The image forming process and each mechanism of an embodiment of the image forming apparatus which constitutes the present invention will be explained using the color image forming apparatus shown in FIG. FIG. 1 is a sectional configuration diagram of a color image forming apparatus showing an embodiment of the present invention. The image forming apparatus of the present invention uses a belt photoconductor in which the base of the belt photoconductor that is an image forming body is formed of a transparent material, and the photoconductor layer is provided on the outer peripheral surface of the transparent base.
This is a structure in which an image exposure unit is arranged inside the belt photosensitive member, and an image forming process unit such as a charging unit, a developing unit, a transfer unit, and a cleaning unit is arranged outside.

The belt photoreceptor 10 which is a belt-shaped image forming body as an image forming body has, for example, an endless belt-shaped base body formed of a transparent polyimide resin or the like inside and a transparent conductive layer on the outer periphery of the base body. , A-Si layer or an organic photosensitive layer (OPC) is formed on the belt, and the driving roller 1, driven rollers 2, 3 and tension roller 4 have the transparent substrate of the belt photosensitive member 10 as the inner surface.
Also, the belt member 10 is stretched around a supporting member 50 provided between the driving roller 1 and the driven roller 2, and the surface of the belt photoreceptor 10 on which the charging, exposing and developing processes are performed is pressed by the supporting member 50 in the clockwise direction. Is driven to rotate. The support member 50 is provided with holes 51Y, 51M, 51C and 51K for scanning exposure light.

In this embodiment, in the photoconductor layer of the belt photosensitive member, which is the image forming point of the exposure beam for image exposure, an appropriate contrast is obtained with respect to the light attenuation characteristics (photocarrier generation) of the photoconductor layer. It suffices that the exposure light amount has a wavelength that can be applied. Therefore, the light transmittance of the transparent substrate of the belt photosensitive member in the present embodiment does not need to be 100%, and may have a characteristic that some light is absorbed when the exposure beam is transmitted. As a material of the translucent substrate, various translucent resins such as polyimide, fluorine, polyester, polycarbonate, polyethylene terephthalate can be used. The light-transmitting conductive layer was made of indium tin oxide (ITO), tin oxide, lead oxide, indium oxide, copper iodide, Au, Ag, Ni, Al, etc. A metal thin film is used, and as a film forming method, a vacuum vapor deposition method, an active reaction vapor deposition method, various sputtering methods, various CVD methods, dip coating methods, spray coating methods and the like are used. As the photoconductor layer, an amorphous silicon (a-Si) alloy photosensitive layer, an amorphous selenium alloy photosensitive layer, or various organic photosensitive layers (OPC) can be used.

A scorotron charger 11 as a charging means
Y, 11M, 11C, and 11K are used in the image forming process of each color of yellow (Y), magenta (M), cyan (C), and black (K), and are different from the above-described organic photoconductor layer of the belt photoconductor 10. Charging is performed by the control grid held at a predetermined potential and corona discharge by the discharge wire, and a uniform potential is given to the belt photosensitive member 10.

Exposure optical systems 12Y and 12 which are image exposure means
M, 12C, and 12K are linear FL (phosphor light emission), EL (electroluminescence), and PL in which light emitting elements arranged in the width direction of the belt photosensitive member 10 are arranged in an array.
(Plasma discharge), LED (light emitting diode), linear LISA (photomagnetic effect optical shutter array) in which elements having an optical shutter function are arranged, PLZT (transmissive piezoelectric element shutter array), LCS (liquid crystal shutter), etc. Of the exposure element and a SELFOC lens as an equal-magnification image forming element, which is attached to a holding member 20 provided inside the belt photosensitive member 10 and read by a separate image reading device. The image signals of the respective colors thus obtained are sequentially taken out from the memory, and the exposure optical systems 12Y, 12
The electric signals are input to M, 12C and 12K, respectively. The emission wavelength of the light emitting device used in this example is 6
It is in the range of 00 to 900 nm.

A developing unit 13Y, which is a developing means using a non-contact developing method for accommodating one-component or two-component developers of yellow (Y), magenta (M), cyan (C) and black (K), respectively. 13M, 13C and 13K are vertically arranged on one side of the vertically arranged belt photosensitive member 10 in parallel with the belt surface at right angles to the moving direction of the belt photosensitive member 10. Developing sleeve 131Y, which rotates in the same direction with a predetermined gap from the peripheral surface of
It includes 131M, 131C and 131K.

The developing units 13Y, 13M, 13C and 13K are the above-mentioned scorotron chargers 11Y and 11Y.
Charging by M, 11C and 11K, exposure optical system 12Y,
The electrostatic latent image formed on the belt photoconductor 10 by image exposure with 12M, 12C and 12K is reversely developed in a non-contact state by applying a developing bias voltage.

The original image is temporarily read as an image signal for each color of Y, M, C and K from an image read by an image pickup device or an image edited by a computer in an image reading apparatus separate from this apparatus. Stored and stored in memory.

When the image recording is started, the photosensitive member driving motor is rotated to rotate the belt photosensitive member 10 in the clockwise direction,
At the same time, application of electric potential to the belt photoconductor 10 is started by the charging action of the scorotron charger 11Y.

After the belt photoconductor 10 is applied with a potential, the exposure optical system 12Y starts exposure by an electric signal corresponding to the first color signal, that is, the image signal of yellow (Y), and the drum is rotationally scanned. An electrostatic latent image corresponding to the yellow (Y) image of the original image is formed on the photosensitive layer on the surface thereof.

The latent image is reversely developed by the developing device 13Y with the developer on the developing sleeve in a non-contact state, and a yellow (Y) toner image is formed in accordance with the rotation of the belt photosensitive member 10.

Next, the belt photosensitive member 10 is further provided with a scorotron charger 11 on the yellow (Y) toner image.
An electric potential is given by the charging action of M, and the exposure optical system 12M
Of the second color signal, that is, an electric signal corresponding to the magenta (M) image signal, is exposed, and the non-contact reversal development by the developing device 13M causes the magenta (M) toner image on the yellow (Y) toner image. ) Toner images are sequentially superposed and formed.

By the same process, a cyan (C) toner image corresponding to the third color signal is further generated by the scorotron charger 11C, the exposure optical system 12C and the developing device 13C, and the scorotron charger 11K and the exposure optical system 12K are also used.
A black (K) toner image corresponding to the fourth color signal is sequentially superimposed and formed by the developing device 13K, and a color toner image is formed on the peripheral surface of the belt photoconductor 10 within one rotation. .

These exposure optical systems 12Y, 12M, 12C
And 12K for exposing the organic photosensitive layer of the belt photosensitive member 10 is performed from the inside of the drum through the transparent substrate. Therefore, the exposure of the image corresponding to the second, third and fourth color signals is performed without any influence of the toner image previously formed, and is equivalent to the image corresponding to the first color signal. It is possible to form an electrostatic latent image. In order to stabilize the temperature inside the belt photosensitive member 10 and prevent the temperature rise due to the heat generated by the exposure optical systems 12Y, 12M, 12C and 12K, a material having good thermal conductivity is used for the holding member 20, and a heater is used at low temperature. In the case of high temperature, it is possible to suppress the heat to the outside by taking measures such as radiating heat to the outside through a heat pipe.

In addition, the replenishing developer for each color is supplied to the replenishing tank 21.
From Y, 21M, 21C and 21K, developing unit 13Y, 1
Replenished to 3M, 13C and 13K. Developer 13
During the developing operation by Y, 13M, 13C and 13K, the developing sleeves 131Y, 131M and 131, respectively.
A developing bias in which a direct current or an alternating current is applied to C and 131K is applied, jumping development is performed by a one-component or two-component developer accommodated in the developing device, and the belt photosensitive member 10 having the transparent conductive layer grounded. By applying a DC bias having the same polarity as that of the toner, non-contact reversal development in which the toner is attached to the exposed portion is performed.

In this way, the color toner image formed on the peripheral surface of the belt photosensitive member 10 is sent out from the sheet feeding cassette 15 and transferred to the timing roller 16 at the transfer portion, and the belt is driven by the timing roller 16. The image is transferred onto a transfer sheet P, which is a transfer material that is fed in synchronization with the toner image on the photoconductor 10, by a transfer roller 14a serving as a transfer device. Further, the transfer roller 14a is synchronized with the transfer paper P fed to the transfer portion by the timing roller 16, and the belt is transferred only during the transfer of the length of the transfer paper P in the circumferential direction of the belt photoreceptor 10. When the transfer process is not performed while being pressed against the photoconductor 10, the pressure is released between the control unit and the transfer roller provided in the image forming apparatus (not shown) so as to be separated from the belt photoconductor 10. Operated by the mechanism.

The transfer paper P on which the toner image has been transferred is separated from the peripheral surface of the drum by the curvature of the driving roller 1 and is then transferred to the fixing device 17 by the transfer belt 14e and heated and pressure-bonded in the fixing device 17 to the toner. After being fused and fixed on the transfer paper P, the paper is ejected from the fixing device 17, conveyed by the paper ejection conveyance roller pair 18a and 18b, and ejected onto the tray above the apparatus via the paper ejection rollers 18.

On the other hand, the belt photosensitive member 10 in which the transfer paper is separated
In the cleaning device 19, the surface of the belt photoreceptor 10 is rubbed by the cleaning blade 19a and the cleaning roller 19b to remove the residual toner and be cleaned, and the toner image of the original image is continuously formed, or is temporarily stopped to start a new original image. The formation of the toner image of. The waste toner scraped off by the cleaning blade 19a and the cleaning roller 19b is discharged to the waste toner container 22 through the toner transport screw 19c and the toner transport pipe 19d. After cleaning, the cleaning blade 19a and the cleaning roller 19b
Is kept away from the belt photoconductor 10 in order to prevent damage to the belt photoconductor 10.

An embodiment of the transparent member for preventing dirt, which is the first object of the present invention, will be described with reference to FIGS. 2 and 3. FIG. 2 is a diagram showing an example of the transparent member, and FIG. 3 is a diagram showing another example of the transparent member. Since each exposure optical system and the transparent member used in each exposure optical system have the same structure and function, the exposure optical system 12Y will be representatively described.

FIG. 2A shows a positional relationship between the transparent member and the exposure optical system with respect to the belt photosensitive member, and FIG. 2B shows a perspective view of the transparent member. Between the image exposure light emission front end portion of the exposure optical system 12Y provided inside the belt photoconductor 10 and the belt photoconductor 10, the cross-section concave type that transmits the image exposure light in parallel to the linear exposure optical system 12Y. A transparent member 30Y is provided. The transparent member 30Y is provided with a belt-shaped surface 35 through which image exposure light is transmitted, and convex portions 31a and 31b at both ends of the surface 35 that are not involved in image exposure. The transparent member 30Y is held by the holding member 20 or the supporting member 50 that holds the exposure optical system 12Y, as will be described later, and the projections 31a and 31b at both ends provided on the transparent member 30Y are in contact with the belt photoconductor 10. Will be placed in.

When the belt photosensitive member 10 is rotated, the belt photosensitive member 10 contacts and slides on the convex portions 31a and 31b, so that the surface 35 is not directly rubbed by the belt photosensitive member 10. Further, the contact surface is also reduced, and a good image having no image exposure unevenness or image streaks can be obtained without causing surface or dot-like toner stains. More preferably, in order to prevent slidability with the belt photosensitive member 10 and toner adhesion to the protrusions 31a, 31b, the sliding portions of the protrusions 31a, 31b have good slidability and little toner adhesion, for example, fluorine resin. A coating film of Teflon resin or coating by baking is applied as a toner adhesion preventing member.

In FIG. 3A, the number of convex portions contacting the belt photosensitive member 10 is further reduced. The portion corresponding to the image exposure scanning area of the convex portions shown in FIG. 2 is cut, and the image exposure scanning of the transparent member 301Y is performed. Convex portions 31a, 31b, 31c, 31d that are in contact with the belt photosensitive member 10 are provided at the four corners outside the area. FIG. 3B shows that both ends of the transparent member 302Y outside the image exposure scanning area where the image exposure scanning is not performed in the image exposure scanning direction,
The convex portions 31a and 31b contacting the belt photosensitive member 10 are provided in the same direction as the rotating direction of the belt photosensitive member 10. Since the belt photosensitive member and the convex portion are in contact with each other outside the image exposure scanning region, the belt photosensitive member is less contaminated.

Also in the embodiment shown in FIG. 3, it is preferable that the sliding portion of the convex portion has good slidability and little toner adhesion in order to prevent slidability with the belt photosensitive member and toner adhesion to the convex portion. For example, a coating film of fluorine resin, Teflon resin, or coating by baking is applied as a toner adhesion preventing member.

Next, an embodiment of a structure for removing stains on the transparent member in order to prevent stains on the transparent member will be described with reference to FIG. FIG. 4 is a diagram showing an example of stain removal.

Between the front end of the exposure section of the exposure optical system 12Y provided inside the belt photosensitive member 10 and the belt photosensitive member 10, a rod-shaped transparent member which transmits image exposure light in parallel with the linear exposure optical system 12Y. The member 303Y is provided in pressure contact with the belt photoconductor 10 with the transparent film 43 interposed therebetween.

The transparent film 43, which is a stain preventing means as a cleaning means, is stretched around the original winding roller 41 and the winding roller 42. For example, the belt photosensitive member 10 is rotated once every 100 copies. At times, when the exposure optical system 12Y is inoperative, it is taken up by the take-up roller 42 in accordance with the rotational speed of the belt photosensitive body 10. When the transparent film 43 is wound, the transparent film 43 rubs the image exposure surface of the transparent member 303Y to clean the image exposure surface of the transparent member 303Y.

The transparent member 303Y and the original winding roller 41 and the winding roller 42 on which the transparent film 43 is stretched are the holding member 20 or the supporting member 5 for holding the exposure optical system 12Y.
It is held at 0.

FIG. 5 shows another embodiment for removing stains on the transparent member. As the transparent member, a round bar transparent member 304Y that is in contact with the belt photosensitive member 10 and is driven to rotate is used. A cleaning blade 44, which is a stain preventing member, is used as a cleaning unit that contacts and cleans toner, dust, and the like on the transparent member.

An embodiment of the arrangement of the transparent member of the above embodiment will be described with reference to FIGS. 6 and 7 using a belt photosensitive unit. FIG. 6 is a diagram showing an embodiment of the belt photoconductor unit, and FIG. 7 is a diagram showing how to attach the transparent member of FIG.

The belt photoconductor unit 100 shown by the dotted line in FIG. 1 includes the developing devices 13Y, 13M, 13C and 13K.
And scorotron charger 11Y, 11M, 11C and 11
K and E are retracted to the right side of FIG. 1, respectively, and then an upper opening / closing lid (not shown) is opened and taken out upward. At this time, a connection part (not shown) with the waste toner container 22 provided on the toner transport pipe 19d is disconnected.

The belt photoreceptor unit 100 includes a housing 1
01 is provided, inside the housing 101, the drive roller 1,
The driven rollers 2 and 3 and the tension roller 4 are the housing 101.
The belt photosensitive member 10 is stretched around each roller. The cleaning device 19 is fixed to the outside of the belt photosensitive member 10, and the supporting members 50 that support the belt photosensitive member 10 are fixed to the inside of the housing 101, respectively. The exposure optical systems 12Y, 12M, 12C and 12K fixed to the
It is attached facing Y, 51M, 51C and 51K. A gear G1 that is coupled to the drive roller 1 and that is rotated by being driven by a drive motor (not shown) provided in the main body of the image forming apparatus is provided outside the housing 101.

Further, the housing 101 has developing devices 13Y, 13
M, 13C and 13K, Scorotron charger 11Y, 1
1M, 11C and 11K joining hole 103, transfer roller 14a operating relief hole 104 and exposure optical system 12Y,
A hole 102 for attaching and detaching the holding member 20 to which 12M, 12C and 12K are fixed is provided. When the holding member 20 is attached to the housing 101, it is locked by a locking member (not shown).

Exposure optical systems 12Y, 12M, 12C and 1
The holding member 20 to which 2K is fixed is the hole 102 of the housing 101.
The holes 210 and 220 provided in the holding member 20 are attached to the support column 105 provided in the housing 101,
Exposure optical system 12
The Y, 12M, 12C and 12K and the belt photosensitive member 10 are positioned.

The transparent member 30Y is fitted into the hole 51Y provided in the support member 50 of the belt photosensitive member 10, and is locked by the locking portions 32a and 32b provided at the side portions of the transparent member 30Y, so that the convex portion 31a. , 31b are provided on the support member 50 while being in contact with the belt photoconductor 10. Locking part 3
2a and 32b may be fixed to the support member 50 by, for example, an adhesive agent, screwing, or the like. The transparent members 30M, 30C and 30K are also attached in the same manner. The holes 210 and 220 provided in the holding member 20 are fitted and attached to the columns 105 and 106 provided in the housing 101, respectively, and the exposure optical systems 12Y, 12M, 12C and 12K and the belt photoconductor 10 are transparent members. 30Y, 30M, 30C and 30K
It is positioned with a pinch in between.

The second embodiment of the present invention, in which the belt photosensitive member and the exposure optical system are positioned, is shown in FIG.
This will be described with reference to FIG. FIG. 8 is a diagram showing an example of how to combine the transparent member, the exposure optical system, and the holding member, and FIG. 9 is a diagram showing another example of how to combine the members.
FIG. 10 is a diagram showing an example of application of a holding member provided with a plurality of exposure optical systems and a transparent member to a belt photoconductor using a belt photoconductor unit, and FIG. FIG. 6 is a diagram showing how to press the belt photoconductor. Figure 6
Members having the same functions and structures as those of the belt photosensitive unit shown in FIG.

As shown in FIG. 8A, the exposure optical system 12
Mounting portions 33a and 33b are provided at both ends outside the image exposure scanning area of the transparent member 30Y facing the Y image exposure emission side.
As shown in FIG. 8B, with the mounting portions 33a and 33b positioned, the exposure optical system 12Y is fixed to the exposure optical system 12Y with an adhesive, for example, at a portion indicated by a black dot, and the transparent member 30Y and the exposure optical system 12Y are connected to each other. The member integrated with is fixed to the holding member 20 of the exposure optical system in the same manner as the portion indicated by a black dot with an adhesive to be integrated with the holding member 20. The holding member 20 to which the exposure optical system 12Y is attached is the transparent member 30.
Y may be attached.

As shown in FIG. 9A, the transparent member 30Y
The exposure optical system 12Y and the exposure optical system 12Y are fixed to each other by adhesives, for example, at the portions indicated by black dots by the coupling members 60a and 60b, and the transparent member 30Y and the exposure optical system 12Y are integrated into a holding member 20 for the exposure optical system. Similarly, it may be fixed to a portion indicated by a black dot with an adhesive and integrated with the holding member 20. In addition, as shown in FIG. 9B, the transparent member 30Y and the exposure optical system 12Y are fixed to the coupling member 61 with an adhesive, for example, at the portions indicated by black dots, so that the transparent member 30Y and the exposure optical system 12Y are separated from each other. The integrated member may be fixed to the holding member 20 of the exposure optical system with an adhesive at a portion indicated by a black dot, and may be integrated with the holding member 20.

The exposure optical systems 12M, 12C and 12K and the transparent members 30M, 30C and 30K are similarly fixed to the holding member 20.

As shown in FIG. 10, the exposure optical system 12Y,
12M, 12C and 12K and transparent members 30Y, 30M,
The holding member 20 to which the respective sets of 30C and 30K are fixed is included in the belt photosensitive member 10 provided inside the housing 101 through the attaching / detaching hole 102 of the holding member 20 provided in the housing 101, and the transparent member 30Y. , 30M, 3
0C and 30K and the holes 51Y, 51M, 51C and 51K provided in the support member 50 of the belt photoconductor 10 are mounted on the belt photoconductor unit 100 so as to face each other.

As shown in FIGS. 10 and 11, the housing 101
The pressing plates 7 (pressing means) pressed by the springs 5a and 5b attached to the spring fixing plates 6a and 6b fixed to the pressing member 7 press the holding member 20 by releasing the pressure release mechanism (not shown), and the transparent member 30Y, The convex portions 31a and 31b provided on each of 30M, 30C and 30K are pressed against the inner surface of the belt photosensitive member 10. Therefore, the respective gaps between the belt photoconductor 10 and the exposure optical systems 12Y, 12M, 12C and 12K are always kept constant, and the belt photoconductor 10 is prevented from floating.

Also in this embodiment, as in the case described with reference to FIG. 2, the convex portions 31a, which are rubbed against the belt photosensitive member 10,
In order to prevent slidability of the belt 31 with the belt photoreceptor 10 and toner adhesion to the convex portions, the sliding portion of the convex portions has a good slidability and little toner adhesion, for example, a coating film of fluororesin, Teflon resin, or baking. It is preferable that a coating such as the above is applied as a toner adhesion preventing member.

Further, in any of the above embodiments, the cross section of the supporting member 50 parallel to the running direction of the belt photosensitive member 10 is convex so that the belt photosensitive member 10 is always in close contact with the supporting member 50. It is preferable that the belt photosensitive member 10 is in contact with the portion.

[0053]

According to the first or second aspect of the present invention, when the belt photosensitive member is rotated, the belt photosensitive member comes into contact with the convex portion and slides, so that the contact surface is reduced and the image of the transparent member is reduced. The exposed surface is not directly rubbed by the belt photoreceptor,
A good image having no image exposure unevenness or image streaks can be obtained without causing surface or dot-like toner stains.

According to the third aspect of the invention, there is further provided an image forming apparatus capable of maintaining a good image without damaging the transparent substrate or reducing the transparency of the image exposure light due to contamination of the transparent substrate. Became possible.

According to a fourth aspect of the present invention, the gap between the belt photosensitive member and the plurality of exposure optical systems is always kept constant, high-precision positioning is performed, the positional relationship between them is maintained, and the belt photosensitive member is maintained. It has become possible to provide an image forming apparatus in which the floating of the image is prevented, the resist for image exposure and the image forming position are not changed, and a good image can be obtained. Further, it has become possible to provide a color image forming apparatus capable of obtaining a good color image by superimposing toner images.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram of a color image forming apparatus showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a transparent member.

FIG. 3 is a diagram showing another embodiment of the transparent member.

FIG. 4 is a diagram showing an example of stain removal.

FIG. 5 is a diagram showing another embodiment for removing stains on a transparent member.

FIG. 6 is a diagram showing an example of a belt photosensitive unit.

FIG. 7 is a view showing how to attach the transparent member of FIG.

FIG. 8 is a diagram showing an example of how to connect a transparent member, an exposure optical system, and a holding member.

FIG. 9 is a diagram showing another embodiment of a coupling method.

FIG. 10 is a diagram showing an example of application of a holding member provided with a plurality of exposure optical systems and a transparent member to a belt photoconductor using a belt photoconductor unit.

FIG. 11 is a diagram showing how a transparent member is pressed against a belt photosensitive member.

[Explanation of symbols]

1 drive roller 2, 3 driven roller 4 Tension roller 7 Pressing means 10 Belt photoreceptor 12Y, 12M, 12C, 12K exposure optical system 20 Holding member 30Y, 30M, 30C, 30K, 301Y Transparent member 302Y, 303Y, 304Y Transparent member 50 Support member 60a, 60b, 61 Coupling member 100 Belt photoconductor unit 101 case

Claims (4)

(57) [Claims] 1. A belt-shaped image forming body which forms a latent image, and an image exposing means disposed inside the belt-shaped image forming body, and the image exposing means performs image exposure from the back surface of the belt-shaped image forming body. In the image forming apparatus in which the image forming apparatus is performed, a transparent film is formed between the belt-like image forming body and the image exposing unit, in contact with the belt-like image forming body, and has a convex portion outside the image exposure light transmission region. An image forming apparatus in which members are provided. 2. The image forming apparatus according to claim 1, wherein the convex portion is provided with a coating film for preventing toner adhesion. 3. A belt-shaped image forming body which forms a latent image, and an image exposing means disposed inside the belt-shaped image forming body, and the image exposing means exposes the back surface of the belt-shaped image forming body. in the image forming apparatus is performed, a transparent member formed on a light-transmitting contact with the belt-shaped image forming body between said image exposing means and the belt-shaped image forming body, the transparent member <br/> An image forming apparatus characterized in that cleaning means is provided in the. 4. A belt-shaped image forming body for forming a latent image, and a plurality of image exposing means arranged inside the belt-shaped image forming body, and the back surface of the belt-shaped image forming body by the plurality of image exposing means. In an image forming apparatus in which image exposure is performed by more than one, a holding member that holds the plurality of image exposing units, a pressing unit that presses the holding members, the belt-shaped image forming body and the image exposing unit, a transparent transparent member in contact with the belt-shaped image forming body provided, wherein said image exposure means and the holding member <br/> bonded integrally with the transparent member, by said pressing means the belt-shaped image forming body An image forming apparatus, wherein pressing is performed via the transparent member.