JPH09300689A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out the stabilized static recording in compliance with photo- emission. SOLUTION: In the constitution of an image forming device, an image carrier 2 having a dielectric layer 23 formed on a conductive layer 21 and a photoelectric conversion device 9 forming a photoelectric conversion layer 14 on the conductive layer 12 are so disposed as to form an electric field on the photoelectric conversion layer 14 in the state of forming a potential difference between both conductive layers 12 and 21 and the image exposure is performed, and a latent image is formed on a traveling image carrier 2 by the discharge between the photoelectric conversion device 9 and the image carrier 2. In that case, a float electrode 16 composed of a conductive body and floating electrically is provided on a surface on the opposite side to the surface facing the conductive layer 12 of the photoelectric conversion layer 14, and a discharge terminal section 18 close to the above-mentioned conductive layer 23 is provided on the float electrode 16.

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 that forms an electrostatic latent image on an image carrier.

[0002]

2. Description of the Related Art Conventionally, as a method for forming an electrostatic latent image on a charge holding medium to form an image, for example, Japanese Patent Laid-Open No.
The method described in Japanese Patent No. 293358 has been proposed. In this image forming method, as shown in FIG. 8, a photosensitive member 101 composed of a small piece and a cylindrical charge holding medium 102 are separately provided. The photoconductor 101 includes a photoconductive layer support 103, a photoconductor electrode 104, and a photoconductive layer 105, which are sequentially stacked. On the other hand, the charge holding medium 102 is
The insulating layer support 106, the charge holding medium electrode 107, and the insulating layer 108 are sequentially stacked. This photoconductor 1
01 and the charge holding medium 102 are arranged so that the photoconductive layer 105 and the insulating layer 108 face each other with a gap therebetween.

Then, a voltage is applied between the photoconductor electrode 104 and the charge holding medium electrode 107, and the photoconductor 101 is placed in a dark place.
When light is incident on the charge carrier 102 to scan it in the axial direction (main scanning direction), the portion of the photoconductive layer 105 on which light is incident exhibits conductivity, and that portion and the insulating layer 108 of the charge carrier medium 102 are A discharge is generated during this period, and charges are accumulated in the insulating layer 108 of the charge holding medium 102 that has been rotated in the direction of arrow b in the figure to form an electrostatic latent image. The formed electrostatic latent image is developed by the developing device 109 to become a toner image,
The toner image is transferred to paper or film by the transfer charger 110.

[0004]

However, when an image is formed by the apparatus shown in FIG. 8 described above, a dot-shaped image is formed or the rear end portion of the image is extended to obtain a stable image. Was difficult. This is the photoconductor 10.
It is considered that the electric discharge from No. 1 to the charge holding medium 102 is not promptly and stably performed, and the electrical discharge is performed intermittently, or the electrical discharge is continued after the exposure is completed. The present invention, the discharge is interrupted in this way,
It is an object of the present invention to provide an image forming apparatus that eliminates continuous discharge after exposure and discharges quickly and stably to record an electrostatic latent image.

Therefore, the inventors of the present invention have found that the image is interrupted,
As a result of examining the phenomenon of trailing edge extension, the discharge point of the photoconductor was not stable and the charge was discharged to a position different from the desired position on the image carrier, which is a charge-holding medium. It has been found that the above-described image discontinuity and trailing edge extension occur due to the fact that the latent image has already been formed on the image carrier and the discharge does not occur.

[0006]

The present invention has been made on the basis of the above findings, and the electric charges generated by the exposure of the photoconductor are stably and repeatedly discharged to desired positions on the image carrier. It was done like this.

That is, the image forming apparatus of the present invention comprises an image carrier having a dielectric layer formed on a conductive layer and a photoelectric conversion device having a photoelectric conversion layer formed on the conductive layer, and a potential difference between the conductive layers. In an image forming apparatus that performs image exposure by arranging so that an electric field is formed in the photoelectric conversion layer in the formed state, and discharges between the photoelectric conversion device and the image carrier to form a latent image on the running image carrier. An electrically floating float electrode made of a conductor is provided on a surface of the photoelectric conversion layer opposite to a surface facing the conductive layer, and the float electrode has a discharge terminal portion in proximity to the dielectric layer. .

In the image forming apparatus having such a structure, when the photoelectric conversion layer is exposed in the state where a desired electric field is formed in the photoelectric conversion layer, carriers are generated by irradiation of light.
Since the float electrode made of a conductor is provided so that the carrier can move freely while being brought into contact with the photoelectric conversion layer, the carriers generated by light irradiation in the photoelectric conversion layer move to the float electrode. The carriers that have moved into the float electrode concentrate on the discharge terminal portion that is closest to the conductive layer of the image carrier, and the discharge terminal portion discharges to the image carrier. In this way, electrostatic recording is performed on the image carrier in accordance with the optical signal.

At this time, regardless of the exposure position of the photoelectric conversion layer, discharge is performed from the discharge terminal portion of the photoelectric conversion device onto the image carrier, so that the discharge position of the photoelectric conversion device is specified and on the image carrier. It is possible to prevent an electrostatic latent image that should be continuous from being discontinuous, or to form an electrostatic latent image even though the position is not irradiated with light.
Therefore, the carriers generated in the photoelectric conversion layer are discharged from a predetermined position, and it is possible to form an electrostatic latent image faithful to a desired image in response to the irradiation of light.

In the electrostatic recording head of the present invention, the float electrode is provided corresponding to a pixel during image exposure, and the contact surface of the float electrode with the photoelectric conversion layer is a spot during image exposure. It is preferably formed larger than the diameter. By forming in this way, if the light irradiation position of the photoelectric conversion layer is a position in contact with the float electrode, stable discharge can be obtained even if the light irradiation position changes, and discharge can be ensured. it can. Also, the exposure position can be adjusted easily, and the cost can be reduced. In addition, the life of the photoelectric conversion layer can be extended by positively changing the exposure position, and a stable image can be secured for a long period of time. Further, the life of the photoelectric conversion device can be extended and the running cost can be kept low.

Further, an accelerating electrode for forming a discharge electric field between the float electrode and the float electrode may be provided at a position distant from the discharge terminal portion of the float electrode on the image carrier side. With this structure, the carriers generated in the discharge terminal portion of the float electrode are more likely to be concentrated, a discharge is generated between the discharge terminal portion and the acceleration electrode, and a part of the carrier is on the image carrier. Discharge to and record electrostatically. The distance between the discharge terminal and the acceleration electrode is constant,
Further, it becomes possible to carry out electrostatic recording by repeating stable discharge. Further, since the allowable width of the gap between the discharge terminal portion of the float electrode and the image carrier is widened and the gap can be easily adjusted, the design and manufacturing are facilitated, and the cost can be reduced.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an image forming apparatus of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram of the image forming apparatus 1 according to the first embodiment.
Shows a partially enlarged sectional view of the photoelectric conversion device 9 and the image carrying belt 2 which are essential parts. At the center of the image forming apparatus 1, an image bearing belt 2 as an image bearing member is disposed.
The image bearing belt 2 is rotated in the direction of arrow a by a driving roller 3 which is rotated by a driving device (not shown) and a heating roller 4 which is provided in parallel with the driving roller 3.

As shown in FIG. 2, the image bearing belt 2 has a dielectric layer 23 formed on the surface of a base 21 which is a conductive layer. Specifically, it is a structure in which a dielectric layer 23 made of polyethylene terephthalate having a thickness of about 10 μm is provided on a base 21 made of a conductive film having a width of 25 cm and a circumference of 30 cm. Further, the base 21 is grounded by a conductive wire 24. Around the image bearing belt 2 described above,
The electrostatic recording head 5, the developing device 6, and the transfer roller 7 are sequentially arranged in the direction of arrow a in the figure.

The electrostatic recording head 5 comprises an optical system 8 and a photoelectric conversion device 9 arranged between the optical system 8 and the image carrying belt 2. The optical system 8 has a housing 81 in which a semiconductor laser generator, a collimator lens, a polygon mirror, an Fθ lens, a reflection mirror, and the like are arranged. The laser light 83 generated by the semiconductor laser generator is applied to the photoelectric conversion device 9 through a slit formed in the housing 81 so that image exposure can be performed. The direction in which the laser beam 83 scans and exposes is the width direction of the image bearing belt 2 (front and back directions in FIG. 1). Hereinafter, this direction is referred to as the main scanning direction, and the image bearing belt 2 travels orthogonal to this main scanning direction. The direction is called the sub-scanning direction.

As shown in FIG. 2, the photoelectric conversion device 9 includes a transparent conductive layer 12 and a photoelectric conversion layer 1 on a transparent substrate 10.
4, the float electrode 16 is laminated in this order, and the float electrode 16 is arranged to face the image carrying belt 2 with a gap therebetween.

The transparent substrate 10 is a transparent glass plate.
The transparent conductive layer 12 is composed of an ITO film as a conductive material and a polyamide resin film as an injection preventing layer. The first power supply 27 is connected to the ITO film of the translucent conductive layer 12.

The photoelectric conversion layer 14 is a function-separated type having good sensitivity to long-wavelength light such as semiconductor laser light (wavelength 780 nm) and LED light (wavelength 680 nm), and is a charge having a carrier pair generation function. Generation layer (CGL) and charge transport layer (CTL) having a function of transporting free carriers
Consists of The photoelectric conversion layer 14 is provided such that its charge generation layer is in contact with the injection prevention layer of the transparent conductive layer 12.

As is apparent from FIG. 3, the float electrodes 16 are provided in contact with the charge transport layer of the photoelectric conversion layer 14, and are arranged in parallel at a predetermined interval in the main scanning direction. And each one corresponds to each pixel at the time of printing. In addition, each float electrode 16 is a photoelectric conversion layer 14
A needle-like tip 18 which is a discharge terminal on the side opposite to the contact surface with
A protrusion 18 having a is formed. This projection 18
Protrudes from the photoelectric conversion device 9 toward the image carrying belt 2, and the needle-like tip 18 a of the float electrode 16 is located closest to the image carrying belt 2.

Incidentally, the photoelectric conversion device 9 and the image carrying belt 2
A spacer may be provided between the photoelectric conversion device 9 and the image carrying belt 2 in order to keep the constant distances between and. The spacer is preferably made of a material such as a fluororesin having a small coefficient of friction with the image bearing belt 2 and being hardly scratched.

The developing device 6 includes a toner containing portion 61 containing a one-component developer (hereinafter referred to as toner) and a developing sleeve 62 arranged in proximity to the image carrying belt 2.
The supply roller 63 supplies toner to the developing sleeve 62 by stirring the toner stored in the toner storage portion 61. The toner used in the developing device 6 is of a negative charging type and has a mean particle size of 10 μm obtained by kneading, pulverizing and classifying a mixture containing a bisphenol A type polyester resin and carbon black as main components by a known method. is there. An appropriate developing bias voltage is applied to the developing sleeve 62 in order to prevent background fogging.

The transfer roller 7 faces the heating roller 4 with the image bearing belt 2 interposed therebetween, and
It is arranged in pressure contact with. The recording paper S is passed between the transfer roller 7 and the image carrying belt 2.

In the image forming apparatus 1 configured as described above, the process of latent image formation will be described first.
The light-transmitting conductive layer 12 of the photoelectric conversion device 9 has the first power source 2
A voltage of 1.2 kV (V _C ) is applied according to 7.
Therefore, the base 2 of the image bearing belt 2 which is grounded
An electric field due to a voltage difference of 1.2 kV is formed between 1 and the transparent conductive layer 12.

The laser beam 8 emitted by the optical system 8 to the photoelectric conversion device 9 in the state where the electric field is formed as described above.
When 3 is irradiated and exposed, the laser beam 83 passes through the transparent substrate (support) 10 and the transparent conductive layer 12, and the photoelectric conversion layer 1
Reach 4 In the charge generation layer of the photoelectric conversion layer 14, when light is absorbed in the presence of an electric field, a carrier pair is generated. Among the generated carrier pairs, the free carriers have the property of moving in the opposite electrode directions of opposite polarities. At this time, the freed positive carriers move to the float electrode 16 through the charge transport layer. As a result, the electric field between the float electrode 16 and the air gap on the surface of the image bearing belt 2 rises, and when this electric field exceeds the threshold value determined by the Paschen's law, discharge occurs. At this time, the tip end 18a of the protrusion 18 of the float electrode 16 is closest to the image bearing belt 2, and a discharge is generated between the tip end 18a and the image bearing belt 2 to reach the exposure position of the photoelectric conversion device 9. The surface of the corresponding dielectric layer 23 of the image bearing belt 2 is charged and an electrostatic latent image is formed.

As is clear from FIGS. 2 and 3, the float electrode 16 is formed in a strip shape extending in the sub-scanning direction. Therefore, when the laser beam 83 is irradiated and exposed, even if the irradiation light is deviated in the sub-scanning direction due to a tilt error of the polygon mirror or the like, the carrier that has moved into the float electrode 16 is within the existing range of the float electrode 16. Float electrode 16
Since it moves freely inside and discharges concentratedly at the tips 18a of the projections 18 closest to the image bearing belt 2, an electrostatic latent image is formed on the image bearing belt 2 at a specific position regardless of the deviation of the exposure position. Can be formed. In addition, by intentionally varying the irradiation light in the sub-scanning direction and using it, the frequency of use of a specific region of the photoelectric conversion layer 14 can be reduced, and as a result, the life of the photoelectric conversion device can be extended. You can

Next, the process after the latent image formation will be described. The electrostatic latent image formed on the image bearing belt 2 is conveyed to a developing unit facing the developing device 6 by the rotation of the driving roller 3 and the heating roller 4, and is developed by the developing device 6 with toner. After that, the toner image formed on the image carrying belt 2 is further conveyed by the rotation of the driving roller 3 and the heating roller 4, and the heating element 11 provided inside the heating roller 4 is conveyed.
At the same time, the transfer roller 7 transfers the heat to the recording paper S. At this time, the toner image is melted and transferred, so that the toner does not remain on the image bearing belt 2 and is almost completely transferred to the recording paper S and is fixed at the same time.

The photoelectric conversion device 9 of the above-described embodiment
As the material, one manufactured by the following method is used. First, a substantially plate-shaped translucent substrate 1 elongated in the main scanning direction
0, more specifically, the transparent conductive layer 12 was formed on the surface of a transparent glass plate having a width of 250 mm in the main scanning direction, a width of 30 mm in the sub scanning direction, and a thickness of 3 mm. The translucent conductive layer 12 is formed by forming an ITO film by a known ion plating method to a thickness of about 0.2 μm (the area resistance of the ITO film is about 100 Ω / □), and further forming an injection prevention layer of about 0 μm thereon. A 0.5 μm polyamide resin layer is applied by the dipping method.

Subsequently, the photoelectric conversion layer 14 is coated with the following photosensitive coating on the surface of the translucent conductive layer 12 of the substrate by the dipping method, and a charge having a film thickness after drying of 0.4 μm is generated. Form the layers. The photosensitive paint is τ (tau) type metal-free phthalocyanine 1 part by weight, polyvinyl butyral resin 2
Parts by weight and 100 parts by weight of tetrahydrofuran are placed in a ball mill pot and dispersed for 24 hours to obtain the product. The viscosity of the photosensitive paint at this time is 15 cp at 20 ° C. The polyvinyl butyral resin has an acetylation degree of 3 mol%.
Hereinafter, those having a degree of butylation of 70 mol% and a degree of polymerization of 1000 were used. Although the charge generation layer is formed by applying a solution of a photosensitive material in a solvent, it may be formed by vapor deposition of the photosensitive material.

Then, 8 parts by weight of a hydrazone compound represented by the following structural formula (Formula 1), 0.1 part by weight of an orange dye, and 10 parts by weight of a polycarbonate resin were placed on the charge generating layer in a solvent consisting of 180 parts by weight of tetrahydrofuran. The dissolved coating solution is applied by a depping method and dried to form a charge transport layer having a film thickness of 21 μm.

[0029]

Embedded image

Next, a plurality of float electrodes 16 are formed in parallel with the main scanning direction as shown in FIG. 3 on the surface of the photoelectric conversion layer 14, more specifically the surface of the charge transport layer. The float electrode 16 is formed of a plurality of strips of conductive paste by screen printing. At this time, the float electrode 16
Has a pitch of 80 μm in the main scanning direction, a width of 50 μm in the main scanning direction, a length of 20 mm in the sub-scanning direction, and a film thickness of 5 μm.
To form. The conductive paste is again applied by screen printing to the substantially central portion of the formed flat float electrode 16, and the height from the flat surface of the float electrode 16 is 10 μm.
Then, a conical protrusion 18 having a bottom surface diameter of 50 μm is formed.

With respect to the structure of the photoelectric conversion layer 14, in addition to the function-separated type described above, it may be a reverse laminated type or a so-called single layer type. Further, as the charge generating material, the charge transporting material, the binder resin, the additive, etc., known materials may be appropriately selected according to the purpose. In addition, the photosensitive material is not limited to the organic material, and an inorganic material such as zinc oxide, cadmium sulfide, selenium alloy, amorphous silicon alloy, amorphous germanium alloy may be used. Also,
For the purpose of improving charging performance, image quality, adhesion to substrates, etc.
A known undercoat layer may be provided. In addition, the transparent substrate 10
Is not particularly limited as long as it is a substrate that is transparent to the exposing light and serves as a support.

For the float electrode 16, a known conductive oxide film, a metal material or the like can be used in addition to the conductive paste. The float electrode 16 is not particularly limited as long as it is electrically conductive, but since it is directly exposed to discharge, it is preferable to use a material that is unlikely to oxidize. Further, the method of forming the float electrode 16 is not limited to this.
Instead of screen printing, the electrodes may be formed by a method such as vapor deposition, ion plating or sputtering. In this case, use a mask sheet,
A pattern is formed by photolithography.

Instead of the ITO film used for the transparent conductive layer 12, a transparent conductive material may be used. However, in order to avoid a voltage drop, it is preferable to use a material having a sheet resistance of 1000 Ω / □ or less. The method for forming the conductive layer is not limited to the method described above, and the conductive material layer may be formed by a method such as printing or sputtering instead of the ion plating method or vapor deposition. Further, the injection preventing layer is not limited to the polyamide resin, and a known material having a light transmitting property may be used.

FIG. 4 shows an image forming apparatus according to the second embodiment of the present invention. This FIG. 4 corresponds to FIG. 2 of the above embodiment. Photoelectric conversion device 9 shown in FIG.
Is almost the same as that of the first embodiment except that the acceleration electrode 19 is provided.
The same reference numerals are given and the description is omitted.

The photoelectric conversion device 9 is similar to the first embodiment, in that the transparent substrate 10 (support), the transparent conductive layer 12, the photoelectric conversion layer 14, and the float electrode 16 having the projection 18 are provided. And a dielectric layer 25 thereon.
Is laminated at a position other than the protrusion 18, and a conductor layer corresponding to the acceleration electrode 19 is formed on the dielectric layer 25. The image bearing belt 2 has the same configuration as that of the above-described embodiment, but a negative voltage is applied to the base 21 by the second power source 28 in order to ensure capture of the discharged charges. ing.

As is clear from FIG. 5, the dielectric layer 25
At the positions where the protrusions 18 of the float electrode 16 are formed, a number of recesses 26 are formed in a row that match the float electrodes 16. Then, the protrusions 1 are formed at the opening edge of each recess 26.
The accelerating electrode 19 is formed in a ring shape in order to promote discharge from the tip 18a of the No. 8. The accelerating electrode 19 is grounded via its terminal portion 19a, and when the potential of the float electrode 16 rises, a potential difference is generated between the accelerating electrode 19 and the tip 18a of the protrusion 18 of the float electrode 16. Also,
The shape of the accelerating electrode 19 is not limited to the ring shape, and may be any shape such that discharge is generated between the tip 18a of the protrusion 18 and a part of the discharged charge reaches the image carrying belt 2. For example, the lines may be formed in parallel lines.

A voltage V _C of 1.2 kv is applied to the translucent conductive layer 12 configured as described above, the accelerating electrode 19 is grounded (0 V), and the conductor of the image carrying belt 2 is made. A minus 1 kv is applied to the base 21 from the second power source 28.

When the photoelectric conversion layer 14 is irradiated with laser light in the state where the above-mentioned respective potentials are maintained by providing the accelerating electrode 19 as described above, the potential of the float electrode 16 including the protrusion 18 rises, and the potential of the protrusion 18 increases. A discharge is generated between the tip 18a and the acceleration electrode 19, and a part of the discharge is drawn by the image carrying belt 2 to form an electrostatic latent image on the dielectric layer 23. By providing such an acceleration electrode 19, the distance between the discharge terminal 18 of the discharge electrode 16 and the image carrying belt 2 can be widened and the allowable width thereof can be widened. Even if the distance between the front end 18a of the sheet and the image carrying belt 2 is changed to some extent, it is acceptable. Therefore, the work at the designing stage and the manufacturing stage becomes easy, and the cost can be reduced. Further, since the distance between the protrusion 18 of the float electrode 16 and the other electrode (accelerating electrode 19) that generates a discharge is always constant, a more stable discharge can be obtained.

As described above, in each of the embodiments, the projection 18 is formed on the float electrode 16 so that the tip end 18a of the projection 18 is closest to the image carrying belt 2.
As in the modified example shown in FIG. 1, the positional relationship between the photoelectric conversion device 9 and the image carrying belt 2 is set, and the end portion 1 of the float electrode 16 is set.
The discharge terminal portion 6a may be closest to the image carrying belt 2.

In the photoelectric conversion device 9 shown in FIG. 6, the photoelectric conversion device 9 arranged in the first embodiment is arranged so as to come to a position rotated by 90 degrees clockwise about the main scanning direction as an axis, and the float electrode. 16 is extended toward the image bearing belt 2 so that the end portion 16a of the float electrode 16 is fixed to the image bearing belt 2.
To be a discharge terminal portion. Specifically, glass plate 1
A plurality of float electrodes 16 extending in the sub-scanning direction are formed in parallel with each other in the main scanning direction, and the photoelectric conversion layer 14 is formed on the float electrodes 16.
Was further laminated, and the transparent conductive layer 12 was further formed on 1/3 on the side opposite to the image carrying belt 2 side to obtain a photoelectric conversion device 9. Further, this is an extreme example, and the one tilted by 90 degrees from the first embodiment is shown.
The end 16a of the float electrode 16 may be brought close to the image carrying belt 2 by inclining it by about 0 degree.

In the image forming apparatus 1 shown in FIG. 7, the float electrode 16 of the photoelectric conversion device 9 is formed flat, and the peak position 29 close to the float electrode 16 is formed on the image carrier side. By thus forming the peak position 29 on the image carrying belt 2, the position closest to the float electrode 16 appears, and the position corresponds to the discharge terminal portion. In the case of the modification shown in FIG. 7, the end portion 16a corresponds to the discharge terminal portion. In this example, the image bearing belt 2 is bent by the roller 22 to form the peak position 20 on the image bearing belt 2, but the image bearing member may be constituted by a drum having a small diameter. .

Although the semiconductor laser is shown as a light source for exposing the photoelectric conversion device 9, the invention is not limited to this, and an LED system or a liquid crystal shutter system may be used as long as the electrostatic recording head 5 can be appropriately exposed. A known exposure method such as the PLZT method can be used. Needless to say, the non-exposed area can be developed without developing the exposed area by changing the characteristics of the developer. The configuration of the image carrier is not limited to such a belt, and may be drum-shaped.

[0043]

As is apparent from the above description, according to the present invention, the charges generated corresponding to the optical information are concentrated on the float electrode, and stable discharge is performed from a specific position of the photoelectric conversion device. Therefore, it is possible to perform desired electrostatic recording without interruption of the image or extension of the trailing edge. Further, it becomes easy to set the irradiation position of the optical information from the light source to the photoelectric conversion device, and the cost can be reduced.

Further, when the accelerating electrode is provided, the gap between the tip of the protrusion and the image carrier can be set wide, and the setting tolerance is wide, so that the degree of freedom in design is further increased. In addition, productivity can be improved, and stable image formation can be performed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to the present invention.

FIG. 2 is an enlarged view of a main part of the image forming apparatus shown in FIG.

FIG. 3 is a diagram showing the surface of the photoelectric conversion device shown in FIG. 2 that faces the image bearing belt.

FIG. 4 is a diagram showing an outline of a main part of a second embodiment.

5 is a diagram showing a surface of the photoelectric conversion device shown in FIG. 4 facing the image bearing belt.

FIG. 6 is a schematic configuration diagram of a main part of a modified example of the image forming apparatus according to the present invention.

FIG. 7 is a schematic configuration diagram of a main part of a further modified example of the image forming apparatus according to the present invention.

FIG. 8 is a diagram showing a conventional image forming apparatus.

[Explanation of symbols]

1 ... Image forming apparatus, 2 ... Image bearing belt (image bearing member), 8
... Optical system, 9 ... Photoelectric conversion device, 12 ... Translucent conductive layer (conductive layer), 14 ... Photoelectric conversion layer, 16 ... Float electrode,
18 ... Protrusion (discharge terminal portion), 19 ... Accelerating electrode, 21 ... Base (conductive layer), 23 ... Dielectric layer, 27 ... First power source.

Claims (3)

[Claims] 1. An image carrier having a dielectric layer formed on a conductive layer, and a photoelectric conversion device having a photoelectric conversion layer formed on the conductive layer are formed into a photoelectric conversion layer with a potential difference formed between the two conductive layers. In an image forming apparatus, which is arranged so that an electric field is formed, is subjected to image exposure, and discharges between a photoelectric conversion device and an image carrier to form a latent image on a running image carrier, and a conductive layer of the photoelectric conversion layer. An image forming apparatus characterized in that an electrically floating float electrode made of a conductor is provided on a surface opposite to an opposite surface, and the float electrode has a discharge terminal portion adjacent to the dielectric layer. 2. The float electrode is provided corresponding to each pixel during image exposure, and the contact surface of the float electrode with the photoelectric conversion layer is larger than the spot diameter during image exposure. The image forming apparatus according to claim 1, characterized in that 3. An accelerating electrode for forming a discharge electric field between the float electrode and the float electrode is provided at a position distant from the discharge terminal portion of the float electrode on the image carrier side by a predetermined distance. 2. The image forming apparatus according to any one of 2 above.