JPH0713408A - Image forming device - Google Patents

Abstract

PURPOSE:To increase the degree of freedom in designing the installation position for an optical writing exposure device and to mlniaturize the device by changing the optical path of image light transmitted through a photoreceptive body and forming an image on a photoconductor layer. CONSTITUTION:A laser exposure device 2 for exposing an image is arranged outside the photoreceptive drum 1. An exposure beam E is transmitted through a light- transmissive photoconductor layer 1-3 of the photoreceptive drum 1, a light-transmissive conductive layer 1-2 and a lighttransmissive supporting body 1-1 in this order, and the optical path of the beam E is changed by a reflection mirror 4 as an optical member constituting optical path changing member fixedly arranged at the inner surface of the photoreceptive drum 1, and the beam is made incident on the light- transmissive supporting body 1-1 again in an electrifying, exposuring and developing area as an abutting part of non-magnetic sleeve 5-2 and the photoreceptive drum 1 so as to form the image on the light-transmissive photoconductor layer 1-3. The incident area A for the exposure beam and the position of the developing device 5 are freely set by properly setting not only the position of the exposure beam E which is reflected by the reflection mirror 4 at almost 90 in such a way, but also the angle of the reflection mirror 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an electrophotographic printer,
The present invention relates to an image forming apparatus which is applied to a digital copying machine, a facsimile or the like and which forms an output image such as black and white, mono color or full color by using an electrophotographic method.

[0002]

2. Description of the Related Art A conventional recording method using an electrophotographic system is to uniformly electrostatically charge the surface of a photoconductor having a photoconductive layer laminated on a conductive layer by a charging device such as a corona. After that, an electrostatic latent image is formed by exposing the image light with an exposure device. Then, the toner charged by the developing device is electrostatically attached to this latent image to visualize it.
Further, this toner image is transferred onto a transfer paper by a transfer device such as a corona, and the toner image on the transfer paper is heated and melted by a fixing device and fixed on the transfer paper to obtain an output image. On the other hand, the residual toner remaining on the photoconductor is removed from the photoconductor by a cleaning device to prepare for the next image forming step.

As described above, since the charging device, the exposure device, the developing device, the transfer device, and the cleaning device are provided around the photosensitive member, the peripheral length of the photosensitive member becomes long, and the device becomes large and the photosensitive drum has a small diameter. However, there was a problem that the device could not be downsized due to this limitation. Furthermore, cleaning and maintenance work for the charging device, transfer device, etc. is required,
The toner removed from the photoconductor was accumulated in the cleaning device, and the processing was troublesome. Further, when a corona charger or the like is used for the charging device and the transfer device, a high voltage of several kilovolts is required and there is a danger of the high voltage.

As a method for solving such a problem, a transparent conductive layer and a photoconductive layer are laminated on a transparent support such as glass or plastic to form a drum or an endless belt. A developing device is provided on the photoconductive layer side of the photographic photoreceptor, and L is provided on the transparent support side which is the inside of the photoreceptor.
An image forming apparatus of a backside exposure recording system has been proposed in which an exposure device using an ED head array, a laser modulator, or the like is provided and image light is focused on the photoconductor layer. Many of these types of devices uniformly charge the photoconductor by injecting electric charges into the surface of the photoconductor via the developer of the developing device to which a developing bias voltage is applied. Then, by performing image exposure from the back surface which is the inside of the photoconductor in the developing area,
The charging, the exposure, and the development are performed substantially in the same manner. With this configuration, the conventional charging device and cleaning device can be eliminated.

However, even in these methods, the LED head array, which is an image exposure device, and the laser exposure device are arranged inside the photoconductor drum and the endless photoconductor belt. There is a problem that the size of the endless photoconductor belt is restricted.

As the exposure apparatus, a fixed scanning type L is currently used.
Various exposure heads such as ED, EL, PLZT, PD, liquid crystal, and optical gate arrays, and mechanical scanning type laser exposure apparatuses have been put to practical use or proposed. Among them, the mechanical scanning type laser exposure device has been most practically used, and because it uses a polygon mirror for mechanical scanning, it is extremely inexpensive compared to other exposure devices, but it can be used as a photosensitive drum or an endless photosensitive belt. There was a problem that it was too large to be placed inside.

The exposure apparatus includes a liquid crystal that requires a light source, a PLZT or an optical gate array, and an LED or an EL that does not require a separate light source, and those requiring a light source have a relatively large size. It is a tendency. Therefore, when the diameter of the photosensitive drum is small, or when the peripheral length of the endless photosensitive belt is short, the usable exposure device is LED or E.
The LED head is limited to the L head, and the LED head is not suitable from the viewpoint of the required light amount, but there is a problem of heat generation of the LED light emitting element,
Further, there is a problem of image quality due to variations among the light emitting elements.

As a method of solving such a problem, toner is supplied to a partial area of the surface of a light-transmissive photosensitive drum to form an exposure and development area, which is disposed outside the photosensitive drum. Image forming method in which an electrostatic latent image is formed and developed at the same time by performing exposure from the back side across the photosensitive drum in a diametrical direction by an optical exposure device for optical writing, and performing image exposure on the photosensitive layer in the developing area. Has been proposed (JP-A-4-
No. 264463).

[0009]

In the above-mentioned conventional example, since the exposure device for optical writing is arranged outside the photosensitive drum, there is no limitation in selection of the exposure device, and an inexpensive and relatively large exposure device is also available. It can be used. However, in order to prevent a decrease in resolution due to refraction when light passes through the photosensitive drum, an exposure device for optical writing arranged outside the photosensitive drum is used to perform exposure so as to traverse the drum in the diameter direction. Since the photosensitive layer in the exposure / development area is image-exposed from the inside of the drum, that is, from the back side, the exposure device and the development region (developing device) are opposed to each other, and the arrangement positional relationship is uniquely determined. Also, even if the optical path of the image light is changed with an optical member such as a mirror on the outside of the photosensitive drum,
The incident position of the image light on the photosensitive drum and the developing region (developing device) are always arranged to face each other, so that there is no freedom in designing the disposing position and there is a problem that the device becomes large.

An object of the present invention is to solve the above-mentioned problems in the conventional image forming apparatus.

[0011]

The present invention is directed to an electrophotographic photosensitive member having a transparent conductive layer and a transparent photoconductive layer on a transparent support, and a transparent photoconductive layer of this photosensitive member. From the body layer side, the image light is incident in a direction substantially perpendicular to the photoconductor, or in the normal direction, and the optical path of the image light is changed by an optical path changing member from the translucent support side of the photoconductor. Optical means for forming an image of the image light transmitted through the photoconductor on the photoconductor layer from an optical member in a direction substantially perpendicular to the photoconductor or a normal direction, and an incident side at an image forming position of the photoconductor. And a developing means for rubbing the developer on the surface of the photoconductor from the opposite side.

[0012]

【Example】

(First Embodiment) Next, the image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a schematic side view showing an embodiment in which the present invention is applied to an image forming apparatus having a rotating cylindrical photosensitive drum. The photosensitive drum 1 is made of glass, hard resin, or the like. On the outer peripheral surface of the cylindrical translucent support 1-1, a translucent conductive layer 1-2 formed by vapor deposition of a metal and a translucent photoconductive layer 1-3 known in electrophotography are laminated. Is configured. A developing device 5 and a transfer roller-10 are arranged around the photosensitive drum 1 so as to face the drum. The developing device 5 is provided with a non-magnetic sleeve 5-2 made of aluminum, stainless steel, or the like, which encloses a magnet roller 5-1 having a plurality of magnetic poles on its circumference, and rotates the magnet roller 5-1. Non-magnetic sleeve 5
-2 or both rotations, the developer 5-3 is supplied so as to come into contact with the photoconductor drum 1 in a brush state, and the photoconductor drum 1 is provided at a portion where the non-magnetic sleeve 5-2 and the photoconductor drum 1 face each other. To form a region (hereinafter, referred to as a charging, exposing and developing region) in which the charging, the exposure and the development are performed substantially simultaneously. Since the developer 5-3 is used to inject charges into the light-transmitting photoconductor layer 1-3 of the photoconductor drum 1 to charge the same, it is a conductive magnetic one component having appropriate conductivity. A toner, a two-component developer composed of a conductive carrier and an insulating toner, or the like is used. Non-magnetic sleeve 5-2
A DC bias is applied between the light-transmitting conductive layer 1-2 of the photoconductor drum 1 and the light-transmitting conductive layer 1-2 by the bias power source 6 used for charging and developing.

On the other hand, a laser exposure device 2 for image exposure is arranged outside the photosensitive drum 1. The exposure beam E from the semiconductor laser 2-1 is the scanner motor 2
It is reflected by the polygon mirror 2-3 rotated at -2, is scanned on the drum 1, and is irradiated onto the photosensitive drum 1 via the Fθ lens 2-4 and the reflection mirror 3. Here, the exposure beam E may be directly irradiated onto the photosensitive drum 1 without passing through the reflection mirror 3. The exposure beam E is applied to the photosensitive drum 1
Of the light-transmitting photoconductor layer 1-3, the light-transmitting conductive layer 1-2, and the light-transmitting support 1-1 in this order, and an optical path changing member fixedly arranged on the inner surface of the photosensitive drum 1. The optical path is changed by the reflecting mirror 4 which is an optical member constituting the non-magnetic sleeve 5.
-2 and the photoconductor drum 1 are in contact with each other in the charging, exposing, and developing regions, and again enter the transparent support 1-1 to form an image on the transparent photoconductor layer 1-3. In the translucent photoconductor layer 1-3 in the region facing the non-magnetic sleeve 5-2 of the developing device 5, the DC bias applied by the charging / developing bias power source 6 causes the developer 5-3 to pass through. The charges are injected into the translucent photoconductor layer 1-3, and the translucent photoconductor layer 1-3 is uniformly charged. When the translucent photoconductor layer 1-3, which is or is being uniformly charged, is irradiated with the image exposure beam E, the charge of the exposed portion is instantaneously transferred to the translucent conductive layer 1-2. The potential is selectively reduced, and the toner, which is the developer, is electrostatically adhered onto the translucent photoconductor layer 1-3 by the DC bias which is the development bias, and the toner image is formed by reversal development. The developed toner image is transferred by the transfer roller 10 onto a transfer paper P which is a transfer material, and is fused and fixed on the transfer paper P by a fixing device (not shown).

On the other hand, a small amount of residual toner remaining on the photoconductor drum 1 without being transferred to the transfer paper P is passed through the charging, exposing and developing areas, and then the translucent photoconductor layer 1-3. The non-magnetic sleeve 5-2 of the developing device 5 is charged at the same time
The magnetic force is collected on the side. Therefore, the residual toner is cleaned and collected after passing through the incident area A of the exposure beam E to the photoconductor drum 1, so that the exposure beam E is shielded by the residual toner, so that the image forming point (nonmagnetic) of the exposure beam E is formed. There is concern that the amount of exposure light in the translucent photoconductor layer 1-3) in the charging, exposure, and development regions, which is the contact portion between the sleeve 5-2 and the photosensitive drum 1, may be nonuniform. Since the amount of residual toner is extremely small and the exposure beam E has not been imaged in the incident area A on the photoconductor drum 1 and the spot diameter is relatively larger than the toner particle diameter, the residual toner has no adverse effect. There is no problem in practical use.

In the present invention, the image forming point of the exposure beam E for image exposure (a light-transmitting photoconductor in the charging, exposing, and developing regions, which is the contact portion between the non-magnetic sleeve 5-2 and the photosensitive drum 1). It is sufficient that the layer 1-3) has an exposure light amount of a wavelength capable of imparting an appropriate contrast to the light attenuation characteristics (generation of photocarriers) of the translucent photoconductor layer 1-3. Therefore, the light transmissivity of the translucent photosensitive drum 1 in the present invention does not have to be 100%, and may have a characteristic that some light is absorbed when the exposure beam E is transmitted. As a material of the transparent support 1-1, various transparent resins such as soda glass, Pyrex glass, borosilicate glass and fluorine, polyester, polycarbonate, polyethylene terephthalate used for general optical members can be used. is there.

The transparent conductive layer 1-2 is made of indium-tin-oxide (ITO), tin oxide, lead oxide, indium oxide, copper iodide, Au, Ag, Ni, Al or the like. A metal thin film that maintains translucency 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.

Further, as the translucent photoconductor layer 1-3,
Amorphous silicon (a-Si) alloy photosensitive layer, amorphous selenium alloy photosensitive layer, and various organic photosensitive layers (OPC)
Can be used.

In the rear exposure recording system as in this embodiment,
In the charging, exposing, and developing regions, an electric charge is injected into the translucent photoconductor layer by a conductive developer, and the charged photoconductor layer is charged and exposed to obtain an injected charge contrast image. In order to develop such an image, it is preferable that the light transmissive photoconductor layer has a large electrostatic capacity because a large injected charge amount can be obtained at a low potential. Therefore, the smaller the thickness of the translucent photoconductor layer is, the larger the electrostatic capacity is. Therefore, as the photoconductor layer used in the present invention, the photoconductor layer used in the conventional electrophotographic image forming apparatus is used. It is thinner than the above and has sufficient transparency.

The translucent photoconductor layer used in this example is 5
The a-Si: H layer having a thickness of 3 μm and the laminated OPC photosensitive layer having a thickness of 3 μm had a laser light transmittance of 780 nm of about 80% and 85%, respectively, which were transmittances that were sufficiently usable.

In the present invention, the translucent photoconductor layer 1-in the area A where the exposure beam E enters the photosensitive drum 1.
3 has optical absorption (about 20%), optical carriers are generated according to the image light, and the influence of the generated optical carriers is
Photocarriers generated at the image formation point of the exposure beam E (translucent photoconductor layer 1-3 in the charging, exposure, and development regions, which is the contact portion between the non-magnetic sleeve 5-2 and the photoconductor drum 1). There are concerns. However, there is no problem because the photocarriers generated in the incident area A of the exposure beam E to the photosensitive drum 1 are canceled when a sufficient charge is injected from the developer in the charging, exposing and developing areas.

In this embodiment, the developing device 5 is arranged at a position where the exposure beam E is reflected by the reflection mirror 4 by about 90 degrees as shown in FIG. 1, but the angle of the reflection mirror 4 may be set appropriately. Thereby, the position of the incident area A of the exposure beam and the developing device 5 can be freely set.

(Second Embodiment) FIG. 2 is a schematic side view showing an embodiment in which the present invention is applied to an image forming apparatus having a plurality of developing devices, the basic construction of which is shown in FIG. There is no particular difference from the image forming apparatus shown, and the corresponding parts are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, the angle (position) of the reflection mirror 4 is set.
By switching between the first position 4-1 and the second position 4-2, the optical path of the image exposure beam E is switched to the two optical paths of the solid line and the broken line, and the image forming position is set to the transparent photoconductor drum 1. The configuration is such that the contact position of the developer of the first developing device 5 and the contact position of the developer of the second developing device 7 are appropriately switched. First and second
In the developing devices 5 and 7, the developing device at the position where the switched exposure beam E forms an image is driven by a drive system (not shown) to selectively abut on the light-transmissive photosensitive drum 1, and the other abuts and separates. .

The first developing device 5 contains the developer 5-3 made of black toner, and the second developing device 7 contains the developer 7-3 made of color toner (for example, red). Is an image forming apparatus that can be selectively used. Developer 5-
3 can use a conductive magnetic one-component toner or a two-component developer composed of a conductive carrier and an insulating toner, and the developer 7-3 is composed of a conductive carrier and an insulating non-magnetic toner. Two-component developers are preferred.

In this embodiment, when the black image output is required, the position of the reflecting mirror 4 is switched to the first position 4-1 and the optical path of the image exposure beam E is set in the direction of the solid line to set the first position. The developing device 5 charges, exposes, and develops the toner, and the transfer device 10 transfers the toner onto the transfer paper P to form a recorded image. Further, when the color (red) image output is required, the position of the reflection mirror 4 is switched to the second position 4-2, the optical path of the image exposure beam E is changed as shown by the broken line, and at the same time the photosensitive drum 1 is moved. The first developing device 5 is separated, the second developing device 7 is moved and brought into contact with the first developing device 5, charging, exposing and developing are performed at the position of the second developing device 7, and then the color (red) toner is transferred. The image is transferred onto the transfer paper P by the device 10 and visualized.

Therefore, according to this embodiment, the optical path of the beam E for exposing an image can be easily switched by the reflection mirror 4 which is an optical member disposed inside the light-transmissive photosensitive drum 1. It is possible to form an image by properly using a plurality of developing devices. Further, by appropriately setting the angle at which the reflection mirror 4 is displaced, the arrangement positions of the developing devices 5 and 7 with respect to the exposure beam E can be arbitrarily set in consideration of other device configurations.

(Third Embodiment) FIG. 3 is a schematic side view showing another embodiment in which the present invention is applied to an image forming apparatus having a plurality of developing devices. The image forming apparatus shown in FIG. 2 is the same as the image forming apparatus shown in FIG.

This embodiment has a reflection mirror 4 which rotates at angles different from those of the second embodiment, and by switching to these angles, the optical path of the image exposure beam E is switched between a solid line and a broken line. That is, the image forming position of the light beam E is set between the contact position between the light-transmissive photosensitive drum 1 and the first developing device 5 and the contact position between the first developing device 5 and the second developing device 7. The configuration is appropriately switched.

In the present embodiment, the developer 5-3 of the first developing device 5 is always in contact with the light-transmissive photosensitive drum 1 at the time of image formation, and the image using the second developing device 7 is used. At the time of formation, the developer of the second developing device 7 may be contact-developed or non-contact-developed with respect to the light-transmissive photosensitive drum 1 at the time of starting exposure.

The first developing device 5 contains the developer 5-3 made of black toner, and the second developing device 7 contains the developer 7-3 made of color toner (for example, red). Is an image forming apparatus that can be selectively used. Developer 5-
3 can be a conductive magnetic one-component toner or a two-component developer composed of a conductive carrier and an insulating toner. Further, as the developer 7-3, in the case of the development in which the second developing device is brought into contact with the drum by the second developing device, an insulating one-component toner or a two-component composed of an insulating carrier and an insulating toner is used. A developer can be used. Conversely, for non-contact development, an insulating one-component toner or a two-component developer composed of an insulating or conductive carrier and an insulating toner is used. It is possible. Here, the insulating one-component toner may be magnetic or non-magnetic.

In this embodiment, when black image output is required, the second developing device 7 is separated so that the drum 1 does not come into contact with the developer, and the position of the reflection mirror 4 is set to 4-1. Switching, the optical path of the image exposure beam E is changed as shown by the solid line, charging, exposure and development are performed in the area where the developer of the first developing device 5 contacts the drum, and the toner image is transferred by the transfer device 10 Transfer to P. When color (red) image output is required, the position of the reflection mirror 4 is switched to 4-2, the optical path of the image exposure beam E is changed as shown by the broken line, and at the same time, the second developing device is attached to the photosensitive drum 1. 7 are brought close to each other, development is performed by the second developing device 7, and color (red) toner is transferred to the transfer paper P by the transfer device 10.

Now, the mechanism of outputting a color (red) image by the second developing device 7 will be described.

When outputting a color (red) image, the reflecting mirror 4 is used.
4-2 is switched to the angular position of FIG. 4-2, the optical path of the image exposure beam E is changed as shown by the broken line, and the non-magnetic sleeve 5-2 of the second developing device 5 and the photoconductor drum 1 come into contact with each other. The light-transmitting photoconductor layer 1-3 in the charging, exposing, and developing regions, which is a part, is not irradiated. Therefore, the first developing device 5
Since no exposure is performed in the charging, exposing, and developing areas, only the uniform charging step is performed on the translucent photoconductor layer 1-3. Since the latent image is not formed because the exposure is not performed, the potential contrast is not formed and the developer 5-3
Do not adhere to the photoconductor layer 1-3. The light-transmitting photoconductor layer 1-3 uniformly charged by the first developing device 5 is then exposed between the first developing device 5 and the second developing device 7 by the image exposure beam E indicated by a broken line. In response to the image exposure irradiation, the electric charge of the exposed portion instantaneously flows to the transparent conductive layer 1-2, the potential is selectively lowered, and an electrostatic latent image is formed. By developing the formed electrostatic latent image with the developer of the second developing device 7, a color (red) image is visualized. The developed toner image is transferred by a transfer roller 10 onto a transfer paper P which is a transfer material,
Then, it is fixed on the transfer paper P by the heating roller fixing device T.

Therefore, when charges are injected and charged from the second developing device into the transparent photoconductor layer 1-3, the electrostatic latent image disappears or a low contrast latent image is formed. When developing with the second developing device 7 in contact with the developer, it is desirable that the developer 7-3 does not contain a conductive substance. Further, when there is a concern about color mixture to the first developing device due to the toner remaining on the drum 1 after the transfer, the drum 1 may be provided downstream of the transfer device and at the drum 1 as appropriate.
It is desirable to dispose a cleaning device (not shown) in the upstream region of the exposure position A to the above.

Therefore, according to this embodiment, the reflection mirror 4 which is an optical member disposed inside the light-transmissive photosensitive drum 1.
The image forming apparatus can easily form an image with a plurality of developing devices by rotating the optical path of the image exposure beam E small by rotating the optical path. Further, by appropriately setting the angle of the reflection mirror 4, the incident area A of the exposure beam E and the arrangement positions of the developing devices 5 and 7 can be freely set. Further, regarding the developer and the developing method used in the developing device arranged on the downstream side of the first developing device 5, since the exposure and the developing steps are sequentially and independently performed, the degree of freedom in materials and conditions is high. It will increase.

(Fourth Embodiment) FIG. 4 is a schematic side view showing another embodiment in which the present invention is applied to an image forming apparatus having a plurality of developing devices. There is no particular difference from the image forming apparatus shown in FIG. 3, corresponding parts are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, there are two sets of image exposure devices 2 and 9 and reflection mirrors 3-1 and 3-2, and the reflection mirror is fixedly arranged inside the light-transmissive photosensitive drum 1. The difference from the third embodiment is that the angle of 4 is not switched.
The optical paths of these two image exposure beams E-1 and E-2 are moved by a fixed reflection mirror to the image exposure beam E-1 (for the solid line, the image forming positions are the light-transmissive photosensitive drum 1 and the first image formation position).
For the image exposure beam E-2 (broken line), the image forming position is set to the first position.
Between the developing device 5 and the second developing device 7. Here, for example, the image exposure beam E-1 (solid line)
Is for irradiating image information for black image output,
The image exposure beam E-2 (broken line) irradiates image information for color (red) image output.

In this embodiment, the first developing device 5 is made of the developer 5-3 made of black toner, and the second developing device 7 is made of the developer 7-3 made of colored toner (for example, red).
The present invention provides an image forming apparatus capable of performing multicolor image formation, in which multi-development is performed each time the translucent photosensitive drum 1 passes through the developing device, that is, within one rotation of the drum.

In this embodiment, the first developing device 5 is always in contact with the transparent photosensitive drum 1 during image formation. On the other hand, when the image is formed by the second developing device 7, the second developing device 7
The developer of the developing device 7 may or may not contact the translucent photosensitive drum 1 depending on the developing method.

As the developer 5-3 of the first developing device, a conductive magnetic one-component toner or a two-component developer composed of a conductive carrier and an insulating toner can be used. As the developer 7-3 of the second developing device, when the device 7 is a contact developing type, an insulating one-component toner or a two-component developer composed of an insulating carrier and an insulating toner can be used. Yes,
When the apparatus 7 is a non-contact developing type, an insulating one-component toner or a two-component developer composed of an insulating or conductive carrier and an insulating toner can be used. Here, the insulating one-component toner may be magnetic or non-magnetic.

In the present embodiment, when a black image output is required, the second developing device 7 is brought into contact with and separated from the drum 1 to separate the developer sufficiently from the drum 1, and the image exposure beam E-1 is used.
The first developing device 5 charges, exposes, and develops only the light. Then, the toner image formed on the drum 1 is transferred onto the transfer paper P by the transfer device 10. When color (red) image output is required, the second
The developing device 7 is moved closer to the developing device 7 and the exposure is performed by the second developing device 7 by irradiating only the image exposure beam E-2, and the color (red) toner is transferred to the transfer paper P by the transfer device 10. .

The mechanism by which the second developing device 7 outputs a color (red) image is the same as in the third embodiment.

Next, the multicolor image forming mechanism performed on the drum 1 will be described. The black image formation as the first image is formed by irradiating the above-mentioned trail image exposure beam E-1.
Charging, exposure and development are performed by the first developing device 5, and the next color image forming a second image is formed between the first developing device and the second developing device by the translucent photoconductor layer 1 -3 non-image area (uniformly charged by the first developing device) is irradiated with a color image exposure beam E-2 (broken line) to expose the electrostatic latent image of the second image. Is formed. By developing this electrostatic latent image with the developer of the second developing device 7, a color (red) image is made visible by superimposing it on the black. The black and color toner images developed in this manner are simultaneously transferred to the transfer paper P, which is a transfer material, by the transfer roller 10 at the same time, and are fixed on the transfer paper P by the fixing device T.

Here, when charges are injected from the second developing device 7 into the transparent photoconductor layer 1-3, the electrostatic latent image disappears or a low contrast latent image is formed. The black toner developed by the first developing device 5 may be stripped off. Therefore, when contact development is performed by the second developing device 7, it is desirable that the developer 7-3 does not contain a conductive substance. In the same manner as above, when there is a concern that the toner remaining on the drum 1 after the transfer may cause color mixing to the first developing device, it is desirable to appropriately install a cleaning device (not shown) on the photosensitive drum 1. .

Therefore, according to the present embodiment, the optical paths of a plurality of image exposure beams can be changed in a predetermined direction by the fixed reflecting mirror 4, which is an optical member disposed inside the light-transmissive photosensitive drum 1. Thus, it is possible to easily form an image with a plurality of developing devices and form a multicolor image on the photosensitive drum 1. Further, by appropriately setting the angle of the reflection mirror 4, the incident positions A and B of the exposure beams E-1 and E-2 and the arrangement positions of the developing devices 5 and 7 can be freely set. In addition, as in the third embodiment, the first developing device 5
The degree of freedom is increased in the developer and the developing method used in the developing device disposed on the downstream side of.

(Other Embodiments) FIG. 5 is a schematic side view showing an embodiment of the image forming apparatus in which the drum-shaped photosensitive member is replaced with the translucent photosensitive belt 1 in the first embodiment. Detailed description is omitted. As the translucent photoreceptor belt 1, a translucent support body 1-1 made of an endless belt using various translucent resin films such as fluorine, polyester, polycarbonate and polyethylene terephthalate used for general optical members is used. On top of that, as the transparent conductive layer 1-2, a transparent film made of indium tin oxide (ITO), tin oxide, lead oxide, indium oxide, copper iodide, Au, Ag, Ni, Al, or the like is provided. A metal thin film which has been maintained is laminated, and as the translucent photoconductor layer 1-3, an amorphous silicon (a-Si) alloy photosensitive layer, an amorphous selenium alloy photosensitive layer, and various organic photosensitive layers (OPC) are further laminated thereon. It is possible to use a laminate of the above.

FIG. 6 is a schematic side view showing the second embodiment of the image forming apparatus using the light-transmissive photoconductor belt 1 according to the second embodiment, and detailed description thereof will be omitted.

7 and 8 show the color image exposure beam E-2 from the outside of the photoconductor 1 between the first developing device 5 and the second developing device 7 in the fourth embodiment. FIG. 9 is a schematic side view showing an embodiment applied to an image forming apparatus that selectively irradiates the light-transmitting photoconductor layer 1-3 directly, and the image forming step is according to the fourth embodiment. The detailed description will be omitted.

[0050]

According to the present invention, image light is emitted from the light-transmissive photoconductor layer side of a photoconductor having a light-transmissive conductive layer and a light-transmissive photoconductor layer laminated on a light-transmissive support. The image light incident on the photoconductor in a direction substantially perpendicular to the photoconductor or in a direction normal to the photoconductor is changed by an optical means so that the image light transmitted through the photoconductor is transmitted by the optical member from the translucent support side of the photoconductor. By forming an image on the photoconductor layer from a direction that is almost perpendicular to the photoconductor or from the normal direction, it is easy to design a device around the photoconductor that is simple, compact, inexpensive, and does not generate ozone. A stable and stable image forming apparatus has become possible.

Further, it has become possible to provide a stable single-color image forming apparatus and a multi-color image forming apparatus which are simple and small in size, are inexpensive, do not generate ozone, and have a high degree of freedom in designing the apparatus arrangement around the photosensitive member. .

[Brief description of drawings]

FIG. 1 is a schematic side view of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic side view of an image forming apparatus according to a second embodiment of the present invention.

FIG. 3 is a schematic side view of an image forming apparatus according to a third embodiment of the present invention.

FIG. 4 is a schematic side view of an image forming apparatus according to a fourth embodiment of the present invention.

FIG. 5 is a schematic side view showing another embodiment of the image forming apparatus according to the present invention.

FIG. 6 is a schematic side view showing another embodiment of the image forming apparatus according to the present invention.

FIG. 7 is a schematic side view showing another embodiment of the image forming apparatus according to the present invention.

FIG. 8 is a schematic side view showing another embodiment of the image forming apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Translucent photoconductor 1-1 Translucent support 1-2 Translucent conductive layer 1-3 Translucent photoconductor layer 2, 9 Image exposure device 3 Reflection mirror 4 Optical member (reflection mirror) 5, 7 Developing Device 6, 8 Developing Bias Power Supply 10 Transfer Device

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical indication location G03G 15/24 21/16 (72) Inventor Yukio Nagase 3-30-2 Shimomaruko, Ota-ku, Tokyo In Canon Inc. (72) Inventor Tatsuya Tada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kiyoshi Sakai 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Takeshi Ikeda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (4)

[Claims] 1. An electrophotographic photoreceptor having a translucent conductive layer and a translucent photoconductor layer on a translucent support, and image light from the translucent photoconductor layer side of the photoreceptor. Incident in a direction substantially normal to the photoconductor, or normal direction,
The optical path of the image light is changed by an optical path changing member, and the image light transmitted through the photoconductor is changed from the light-transmissive support side of the photoconductor to a direction substantially perpendicular to the photoconductor or from the normal direction. An image forming apparatus comprising: an optical unit for forming an image on a conductor layer; and a developing unit for rubbing a developer on the surface of the photoconductor from the side opposite to the incident side at the image formation position of the photoconductor. 2. An optical path changing member for changing the irradiation direction of the image light transmitted through the photoconductor to a predetermined direction is provided on the light transmissive support side of the photoconductor according to claim 1. The image forming apparatus according to claim 1. 3. The image forming apparatus according to claim 1, wherein the optical path changing member according to claim 2 can switch the optical path of the image light after passing through the photoconductor to a predetermined angle. . 4. The developing unit according to claim 3, wherein the image forming position of the photosensitive member switched by the optical path changing member is provided with a developing unit to which developers of different colors are applied. The image forming apparatus described.