JP2002107981A - Electrophotographic photoreceptor, image forming method using the same, image forming device, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor, an image forming method, an image forming device, and a process cartridge, by which the potential performance change is little with respect to exposure hysteresis even in a long use for image formation and an image failure is provided, in an image forming process of forming superimposed images of two or more colors on the electrophotographic photoreceptor. SOLUTION: The electrophotographic photoreceptor is used for the image forming method in which the uniformly electrified, single electrophotographic photoreceptor is image-exposed by a digital exposure device, the formed electrostatic latent images are developed plural developing device disposed along the peripheral edge of the photoreceptor in order to form superimposed images of many colors on the photoreceptor, and the superimposed images are transferred to a transfer material all at one. The electrophotographic photoreceptor uses pigment particles that are obtained by allowing particles of polycyclic anhydride aromatic diamine condensate composed to contain metal atoms.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member used in an image forming section of, for example, a color copying machine or a color printer, an image forming method, an image forming apparatus, and a process cartridge.

[0002]

2. Description of the Related Art In an electrophotographic image forming method,
2 on the electrophotographic photoreceptor (sometimes simply called photoreceptor)
In the process of forming a multi-color superimposed image of more than one color, in the case of superposition, the same portion is exposed two or more times during one image formation.

At this time, after the second color exposure, erasing exposure before charging is usually not performed for the purpose of preventing image deletion. For this reason, the characteristic difference between the exposed part and the unexposed part tends to increase so much as to be incomparable with the single-color process, and an electrophotographic photoreceptor having a small change in chargeability and sensitivity depending on the exposure history is required.

At present, in an apparatus in which a multi-color superimposed image is formed on a photosensitive member and an image is formed by collectively transferring the image onto a transfer material, 780 is used as an exposure light source from the viewpoint of availability, reliability, cost, and the like. A ~ 800 nm laser diode is used. Therefore, an electrophotographic photoreceptor using a phthalocyanine compound having high photosensitivity at this wavelength as a charge generating substance is used.

However, the same image pattern is continuously printed (copied) on a photoreceptor using a phthalocyanine compound.
In this case, there is a difference in charging performance between a part with a strong exposure history and a part with a weak exposure history (a decrease in charging performance in a part with a strong exposure history).
There is a problem that unevenness occurs in the halftone image area, which is an obstacle to high image quality and high durability.

JP-A-6-250416 discloses an example of the use of an electrophotographic photoreceptor using an imidazole perylene compound, which is a condensed polycyclic compound, as a charge-generating substance, assuming that the fluctuation in charging performance is small. A photoreceptor using an aromatic diamine condensate compound such as imidazole perylene as a charge generating substance has a stable charging performance, but has a reduced sensitivity in areas where the exposure history is strong (the amount of exposure per unit time is large). It is easy to cause a memory phenomenon in which the density is partially reduced and a density reduction as a whole,
It is insufficient for long-term stable use.

After all, in the above-described process of forming a multi-color superimposed image of two or more colors on a photoconductor, at present, no photoconductor having satisfactory electrophotographic performance has been developed.

[0008]

SUMMARY OF THE INVENTION
In an image forming process for forming a color superimposed image of a color or more, a difference in exposure history in image formation is more likely to occur depending on a portion of a photoconductor than in a monochromatic process. Therefore, there is a demand for an electrophotographic photosensitive member that does not cause a difference in charging performance depending on the exposure history.

The present invention has been made to meet this demand, and has a small change in potential performance with respect to exposure history even when used for a long period of time in image formation, and does not cause image defects. And an image forming method, an image forming apparatus, and a process cartridge.

[0010]

The present inventors have conducted intensive studies and found that the object of the present invention can be attained by adopting the following constitution.

[1] A single electrophotographic photosensitive member uniformly charged is image-exposed by a digital exposure device, and the formed electrostatic latent image is developed by a plurality of developing devices arranged on the periphery of the photosensitive member. In the electrophotographic photoreceptor used in the image forming method of forming a multicolor superimposed image on the photoreceptor and collectively transferring it to a transfer material, the metal compound is contained in the aromatic diamine condensate compound particles of the polycyclic anhydride. An electrophotographic photoreceptor comprising pigment particles obtained by mixing a compound containing atoms.

[2] The electrophotographic photosensitive member according to [1], wherein the aromatic diamine condensate compound of a polycyclic anhydride is a bisimidazole perylene compound represented by the above compound (1).

[3] The electrophotographic photosensitive member according to [1], wherein the pigment particles obtained by containing a metal atom are a metal phthalocyanine compound.

[4] The aromatic diamine condensate compound of the polycyclic anhydride is a bisimidazole perylene compound represented by the above-mentioned compound (1), and the pigment particles obtained by containing a metal atom are metal phthalocyanine compounds. The electrophotographic photosensitive member according to [1], wherein:

[5] The electrophotographic photosensitive member according to [4], wherein the concentration of the hybrid metal phthalocyanine is in the range of 0.2 to 10% by mass.

[6] A single uniformly charged electrophotographic photosensitive member is image-exposed by a digital exposure device, and the formed electrostatic latent image is developed by a plurality of developing devices arranged on the periphery of the photosensitive member. Then, a multicolor superimposed image is formed on the photoreceptor, and an image forming method of batch-transferring to a transfer material, the electrophotographic photoreceptor includes a metal atom in the aromatic diamine condensate compound particle of the polycyclic anhydride. An image forming method using pigment particles obtained by mixing a compound contained therein.

[7] A single uniformly charged electrophotographic photosensitive member is image-exposed by a digital exposure device, and the formed electrostatic latent image is developed by a plurality of developing devices arranged around the periphery of the photosensitive member. Then, in an image forming apparatus for forming a multicolor superimposed image on the photoreceptor and collectively transferring it to a transfer material, a metal atom is contained in the aromatic diamine condensate compound particle of the polycyclic anhydride on the electrophotographic photoreceptor. An image forming apparatus using pigment particles obtained by mixing a compound contained therein.

[8] The image forming apparatus according to [7], which is configured to be freely inserted into and removed from the image forming apparatus, wherein at least one of the electrophotographic photosensitive member and a uniform charger, a developing device, a transfer / separator, or a cleaning device is integrated. A process cartridge characterized by being combined.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below.

The mixing of the compound containing a metal atom in the pigment particles in the present invention will be described. First, an operation of mixing a plurality of substances at the molecular level in the pigment particle production stage will be referred to as hybridization, and particles containing a plurality of substances and compounds produced through the same operation will be referred to as hybrid pigments or hybrid pigment particles. . The pigment particles of the present invention were developed using the hybrid pigment particles as a basic technology.

Here, the hybrid pigment particles described in the present invention will be described in detail. First, the hybrid pigment particles are characterized in that a plurality of substances (for example, a pigment and a metal atom-containing compound) are once mixed at a molecular level in a particle manufacturing stage. Thereafter, the particles are formed as particles containing a plurality of substances and compounds at the same time in order to perform an operation of forming particles.

Some of the hybridized substances and compounds are incorporated into the particles in a molecular state, so that depending on the energy level of the hybridized substances and compounds, an impurity level may be created in the semiconductor mechanism of the charge generating substance, so It was speculated that this could be a solution to various problems that might be caused by the trap level.

Also, after the dispersion treatment or the like is performed on the composite pigment and the mixture is pulverized to a state where a photosensitive layer which does not cause image defects can be formed, a plurality of types of substances mixed during the preparation of the composite pigment remain in the particles.
Compound is contained.

On the other hand, in the mixing of pigments, it is considered that a plurality of pigments exist independently as particles at any stage of mixing and dispersion from the time of preparation of the pigment particles. Even if the pigment particles are dissolved or penetrated into the particles in a dissolved state, the state is different from that of the hybrid pigment particles obtained from a homogeneously dispersed state at the molecular level such as a hybrid.

The electrophotographic photoreceptor using the specific hybrid pigment particles of the present invention obtained as described above as a charge-generating substance has a small decrease in sensitivity upon exposure to a large amount of light, and is exposed to light even after a pause after repeated use. The difference in chargeability between the first and second rotations of the body is small. In addition, it exhibits extremely stable electrophotographic performance against changes in environmental conditions such as temperature and humidity, and maintains excellent electrophotographic performance even when used repeatedly for a long period of time. Due to these excellent characteristics, a stable electrophotographic image can be provided in various environments and electrophotographic process conditions.

In order to specifically explain the excellent characteristics of the present invention, examples of materials and layer constitutions which can be used for constituting an electrophotographic photoreceptor are shown. It is not limited at all.

The aromatic diamine condensate compound of polycyclic anhydride in the present invention means a condensate compound of polycyclic anhydride and aromatic diamine. The following compounds (1) to (16) are shown as examples. Among these, the number of condensed rings of the polycyclic anhydride is preferably 2 to 7, for example, compound (2),
In (3), two compounds, in compounds (6) and (16), seven compounds, and in other compounds, five compounds can be exemplified. Among them, the most preferred aromatic diamine condensate compound of polycyclic anhydride is bisimidazole perylene of compound (1). Compound (1) has structural isomers, but compound (2)
The compounds (1) to (16) may contain isomers thereof as in the case of the compound (1).

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Next, a compound containing a metal atom is a compound in which a metal atom is present in at least one of the constituent atoms in the compound, but is more preferably a metal chelate compound, Those having photoconductivity are preferred. More preferably, it is a phthalocyanine metal chelate compound.

The mixing ratio of the compound containing a metal atom is preferably in the range of 0.2 to 10% by mass.

Representative examples of the production of these hybrid pigment particles are shown below. Next, a synthesis example of the hybrid pigment of the present invention is shown below.

Synthesis Example 1 0.3 g of titanyl phthalocyanine and 30 g of the compound (1) bisimidazole perylene were added to 900 ml of concentrated sulfuric acid at room temperature, and the mixture was further stirred for 2 hours. The sulfuric acid solution was filtered through a glass filter to remove insolubles, and then poured into 15 liters of water while maintaining the water temperature at 30 ° C. or lower. After the precipitated particles were filtered, they were further washed three times with 5 liters of water. The wet cake obtained by the filtration is once frozen, then thawed, filtered and dried to obtain 28 of the composite pigment particles (1).
g was obtained.

Synthesis Example 2 26.5 g of hybrid pigment particles (2) were obtained in the same manner as in Synthesis Example 1 except that 0.3 g of copper phthalocyanine was used instead of titanyl phthalocyanine.

Synthesis Example 3 27 g of hybrid pigment particles (3) were obtained in the same manner as in Synthesis Example 1 except that 0.3 g of vanadium oxyphthalocyanine was used instead of titanyl phthalocyanine.

Synthesis Example 4 In the same manner as in Synthesis Example 1 except that 0.3 g of lead phthalocyanine was used instead of titanyl phthalocyanine, 26 g of hybrid pigment particles (4) were obtained.

Synthesis Example 5 28.5 g of hybrid pigment particles (5) were obtained in the same manner as in Synthesis Example 1 except that 0.3 g of zinc phthalocyanine was used instead of titanyl phthalocyanine.

Synthesis Example 6 Synthesis Example 1 except that the amount of titanyl phthalocyanine was 3 g
In the same manner as in the above, 29.5 g of hybrid pigment particles (6) were obtained.

Synthesis Example 7 Copper phthalocyanine 3 in place of titanyl phthalocyanine
Except for using g, 30.5 g of hybrid pigment particles (7) were obtained in the same manner as in Synthesis Example 1.

Synthesis Example 8 30 g of hybrid pigment particles (8) were obtained in the same manner as in Synthesis Example 1 except that 3 g of vanadium oxyphthalocyanine was used instead of titanyl phthalocyanine.

Synthesis Example 9 Hybrid particles produced in the same manner as in Synthesis Example 6 were taken out at the stage of a wet cake after washing and filtration, and were mixed with 70 parts of orthodichlorobenzene (ODB) / water = 500 ml / 200 ml.
The mixture was heated and stirred at 6 ° C. for 6 hours. Further, after sufficiently washing with methanol and drying, 24 g of hybrid pigment particles (9) were obtained.

Synthesis Example 10 A wet cake stage after washing and filtering hybrid particles prepared in the same manner as in Synthesis Example 1 except that 13.5 g of titanyl phthalocyanine and 16.5 g of bisimidazole perylene of the compound (1) were used. At 70 ° C. in ortho-dichlorobenzene (ODB) / water = 500 ml / 200 ml
And stirred for 6 hours. Further, after sufficiently washing with methanol and drying, 25.6 g of a mixed pigment particle (10) was obtained.

Synthesis Example 11 The hybrid particles produced in the same manner as in Synthesis Example 10 were dried once, and then heated in 500 ml of 2-butanone under reflux for 6 hours.
Stirred. Further, after sufficiently washing with methanol and drying, 23.8 g of a mixed pigment particle (11) was obtained.

In the present invention, a laminated photoreceptor having a charge generation layer as a lower layer and a charge transport layer as an upper layer can be obtained. Further, a single-layer type photoreceptor can be obtained by mixing and dispersing a charge generating substance, a charge transporting substance and other additives. It is also possible to provide a photoconductor in which the lower layer contains a charge transporting substance and the upper layer contains a charge generating substance. In any layer configuration, a protective layer may be provided on the photosensitive layer. Further, an intermediate layer may be provided between the conductive substrate and the photosensitive layer.

In forming the photosensitive layer, the charge generating layer is formed by applying a liquid in which the charge generating substance is dispersed alone or in fine particles together with a binder or an additive in an appropriate dispersion medium, or by vacuum deposition of the charge generating substance. Is valid.
In the former case, as the dispersing means, a dispersing device such as an ultrasonic dispersing machine, a ball mill, a sand mill, and a homomixer can be used.

The charge transport layer can be formed by applying and drying a solution prepared by dissolving the charge transport substance alone or together with a binder or an additive using an applicator, bar coater, dip coater, ring coater or the like. it can. The intermediate layer, the charge generation layer, the protective layer and the like can be formed by the same means.

Examples of the polymer useful as a binder used in the photosensitive layer and the protective layer include polystyrene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin,
Examples include polyurethane resins, phenol resins, polyester resins, alkyd resins, polycarbonate resins, silicone resins, melamine resins, and copolymer resins containing two or more of these repeating units. Further, in addition to these insulating resins, a polymer organic semiconductor such as polyvinyl-N-carbazole may be used.

Examples of the dispersion medium of the charge generating substance and the charge transporting substance include hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and 1,2-dichloroethane; ketones such as methyl ethyl ketone and cyclohexanone; Esters such as ethyl and butyl acetate;
Methanol, ethanol, propanol, butanol,
Alcohols such as methylcellosolve and ethylcellosolve and derivatives thereof; ethers such as tetrahydrofuran, 1,4-dioxane and 1,3-dioxolane; amines such as pyridine and diethylamine; amides such as N, N-dimethylformamide And other fatty acids and phenols; one or more of sulfur and phosphorus compounds such as carbon disulfide and triethyl phosphate.

The ratio of the charge generating substance to the binder was 1 to 6 parts per 100 parts by mass of the binder.
00 parts by mass is desirable. The ratio of the charge transporting substance to the binder is preferably 10 to 500 parts by weight based on 100 parts by weight of the binder. The thickness of the charge generation layer is preferably from 0.01 to 20 μm. The thickness of the charge transporting layer is generally from 1 to 100 μm, preferably from 5 to 50 μm. In the case of a single-layer type electrophotographic photoreceptor, the ratio of binder: additive: charge generating substance: charge transporting substance is preferably 100: 1 to 200: 1 to 200: 1 to 200. The thickness is preferably 5 to 50 μm.

As the conductive support, a metal plate or a metal drum may be used, or a thin layer of a conductive compound such as a conductive polymer or indium oxide, or a metal such as aluminum or palladium may be applied, vapor-deposited or laminated. What is provided on a substrate such as paper or a plastic film by means can be used.

In the photosensitive layer in the present invention, any compound such as a triphenylamine derivative, a triphenylamine-styryl derivative, a hydrazone derivative, a tetraphenylbenzidine derivative, and a butadiene derivative can be used as a charge transporting substance. Specific examples are shown below.

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In the photosensitive layer, an antioxidant can be added. Examples of the antioxidant include hindered phenols, hindered amines, paraphenylenediamines, hydroquinones, and organic phosphorus compounds.

The photoreceptor may further contain, if necessary, an ultraviolet absorber or a dye for color sensitivity correction for the purpose of protecting the photosensitive layer.

After the composite pigment particles of the present invention are synthesized, they can be converted into a desired crystal form by means of a suitable solvent treatment or the like.

The image forming method and the image forming apparatus of the present invention
Exposure and development are sequentially repeated to form a color superimposed image on the photoreceptor based on a multicolor image signal, and a color image is formed by transferring the image at once.

In this case, there is provided a mechanism for loading a process cartridge formed by combining an electrophotographic photosensitive member with at least one of a charger, an image exposing unit, a developing unit, a transfer or separation unit, and a cleaning unit. Is preferred.

First, a charge is applied to the surface of the photoreceptor by a charger such as a corotron, a scorotron, a conductive brush, and a conductive roller, and then controlled by an information processing signal from a computer or the like and a digital image signal sent from a storage medium. Exposure is usually made in the form of dots from a light source such as a laser, LED, or liquid crystal shutter.

The photoreceptor erases the surface charge by exposure and forms an electrostatic latent image. The image signal is normally separated into four colors of cyan, magenta, yellow, and black. After an electrostatic latent image corresponding to each color is formed, a developing device (developing device) corresponding to each color is formed. Are sequentially developed.

To transfer a toner image developed by a dry developer from a photoreceptor onto a transfer material (usually a transfer paper such as plain paper), the electrostatic force of the opposite polarity to that of the toner is mainly used.
A corotron, a scorotron, a conductive brush, a conductive roller, or the like is used. At the same time, a pressure member may be used in combination to impart a transfer effect by pressure.

The residual toner after the transfer is removed by a cleaning device (cleaning device). As a cleaning method, blade cleaning is usually used, and a cleaning brush, a web, a magnetic brush, or the like can be used in combination.

The electrophotographic photoreceptor of the present invention can be applied to general electrophotographic devices such as copiers, laser printers, LED printers, and liquid crystal shutter printers. It can be widely applied to devices such as light printing, plate making, and facsimile.

FIG. 1 is a sectional view of an image forming apparatus equipped with the electrophotographic photosensitive member of the present invention. In FIG. 1, reference numeral 10 denotes a photoreceptor drum (photoreceptor) serving as an image carrier, which is a photoreceptor having an organic photosensitive layer applied on the drum, and which is grounded and driven to rotate clockwise. Reference numeral 11 denotes a scorotron charger, which applies uniform charging to the peripheral surface of the photosensitive drum 10 by corona discharge. Prior to the charging by the charger 11, in order to eliminate the history of the photoconductor in the previous image formation, the peripheral portion of the photoconductor may be discharged by performing exposure by an exposure unit using a light emitting diode or the like.

After the photosensitive member is uniformly charged, the image exposure device 12
(Exposure optical system) performs image exposure based on the image signal. The image exposure device 12 in this figure uses a laser diode (not shown) as an exposure light source. Rotating polygon mirror 13
1. The light on the photosensitive drum is scanned by the light whose optical path is bent by the reflection mirror 132 through the fθ lens and the like, and an electrostatic latent image is formed.

The electrostatic latent image is developed by the developing unit 13. At the periphery of the photoreceptor drum 10, developing devices 13 each containing a developer including a toner such as yellow (Y), magenta (M), cyan (C), and black (K) and a carrier.
First, development of the first color is performed by a developing sleeve 141 which rotates with a built-in magnet and holding a developer. The developer comprises, for example, a carrier in which an insulating resin is coated around a ferrite core, and a toner in which a pigment corresponding to a color and a charge control agent, silica, titanium oxide, etc. are added using polyester as a main material. The developer is regulated to a layer thickness of 100 to 600 μm on the developing sleeve 141 by a layer forming means (not shown), and is conveyed to a developing area to be developed. At this time, normally, a DC and / or AC bias voltage is applied between the photosensitive drum 10 and the developing sleeve 141 to perform the development.

In the color image formation, after the visualization of the first color is completed, the image forming process of the second color is started, and the uniform charging is performed again by the scorotron charger 11 to form the latent image of the second color. The exposure unit 12 is formed. An image forming process similar to that for the second color is performed for the third color and the fourth color, and a visible image of four colors is formed on the peripheral surface of the photosensitive drum 10.

On the other hand, in a monochrome electrophotographic apparatus, the developing device 1
Numeral 3 is composed of one kind of black toner and can form an image by one development.

After the image is formed, the recording paper P is fed to the transfer area by the rotation of the feed roller (timing roller) 16 at the time when the transfer timing is adjusted.

In the transfer area, a transfer roller (transfer device) 1 is mounted on the peripheral surface of the photosensitive drum 10 in synchronization with the transfer timing.
8, the multicolor image is transferred collectively by sandwiching the fed recording paper P.

Next, the recording paper P is neutralized by a separation brush (separator) 19 which is brought into pressure contact with the transfer roller almost at the same time, and is separated by the peripheral surface of the photosensitive drum 10 to be conveyed to the fixing device 17 where it is fixed. After the toner is fused by heating and pressing of the pressure roller 17a and the pressure roller 17b, the toner is discharged to the outside of the apparatus via the paper discharge roller 21. The transfer roller 18 and the separation brush 19 are retracted and separated from the peripheral surface of the photosensitive drum 10 after the recording paper P has passed to prepare for the formation of the next toner image.

On the other hand, the photosensitive drum 10 from which the recording paper P has been separated removes and cleans the residual toner by pressing the blade 221 of the cleaning device (cleaning device) 19.
The image is again discharged by the exposure unit and charged by the charger 11 to start the next image forming process. When a color image is formed on the photoconductor by superimposition, the blade 221 moves immediately after the cleaning of the photoconductor surface and retreats from the peripheral surface of the photoconductor drum 10.

Reference numeral 30 denotes a detachable cartridge in which a photosensitive member, a charger, a transfer device / separator and a cleaning device are integrated.

An electrophotographic image forming apparatus is constructed by integrally combining the above-described photosensitive member, a developing device, a cleaning device, and other components as a process cartridge, and this unit is configured to be detachable from the apparatus main body. You may.
Also, a process cartridge is formed by integrally supporting at least one of a charger, an image exposing unit, a developing unit, a transfer or separating unit, and a cleaning unit together with a photoreceptor. It may be configured to be detachable using a guide means such as a rail of the apparatus body.

When the image forming apparatus is used as a copying machine or a printer, the image exposure is performed by irradiating the photoreceptor with light reflected or transmitted from the original, or by reading the original with a sensor and converting it into a signal. Scanning of a laser beam, driving of an LED array, or driving of a liquid crystal shutter array is performed by irradiating the photosensitive member with light.

When used as a facsimile printer, the image exposure unit 13 performs exposure for printing received data.

[0081]

EXAMPLES In order to specifically explain the excellent characteristics of the present invention, a photoreceptor was manufactured by changing a charge generating material and a layer configuration used for forming an electrophotographic photoreceptor, and evaluated. Is shown. However, the present invention is not limited to these specific examples.

In this embodiment, "parts" means "parts by mass". 1. Hybrid pigment particles (charge generating substance) Hybrid pigment particles 1 Pigment particles of Synthesis Example 1 (imidazole perylene + TiOP
hc1%)% is mass% (Phc represents phthalocyanine; the same applies hereinafter).

Hybrid pigment particles 2 Pigment particles of Synthesis Example 2 (imidazole perylene + CuPh
c 0.3%) Hybrid pigment particles 3 Pigment particles of Synthesis Example 3 (imidazole perylene + VOPh)
c1%) Hybrid pigment particles 4 Pigment particles of Synthesis Example 4 (imidazole perylene + PbPh)
c5%) Hybrid pigment particles 5 Pigment particles similar to those in Synthesis Example 4 except that (imidazole perylene + PbPhc 10%) Hybrid pigment particles 6 Synthesized in the same manner as the pigment particles in Synthesis Example 1, but the compound was a combination of imidazole perylene + dibromoansansthrone. .

Hybrid pigment particles 7 Synthesized in the same manner as the pigment particles of Synthesis Example 1, except that the compound was a combination of imidazole perylene and metal-free phthalocyanine.

2. Conductive Substrate Substrate 1 An aluminum pipe having a surface roughness (Rz) of 1.0 to 1.5 μm and a diameter of 120 mm and a length in the width direction of 360 mm was produced by lathing.

Substrate 2 A transparent acrylic pipe produced by centrifugal polymerization was turned into a resin pipe having a surface roughness (Rz) of 0.3 to 0.5 μm and a diameter of 120 mm and a length of 360 mm.

3. After dissolving 3 parts of the intermediate layer liquid CM8000 (manufactured by Toray Industries, Inc.) in a mixed solvent of 80 parts of methanol and 20 parts of butanol, the roughness was 0.5 μm.
The mixture was filtered through a filter of m to prepare an intermediate layer liquid.

4. Charge generation layer liquid Charge generation layer liquid 1 18 parts of hybrid pigment particles of Synthesis Example 1, 6 parts of butyral resin,
350 parts of 2-butanone and 70 parts of cyclohexanone were dispersed in a sand mill for 40 hours to prepare a charge generation layer liquid.

Charge generation layer liquid 2 Bragg angle 2θ 9.5 ° with respect to CuKα characteristic X-ray
24.1 ° 10 parts of titanyl phthalocyanine having a peak at 27.2 °, 5 parts of butyral resin, tert-acetic acid
350 parts of butyl and 70 parts of methyl isopropyl ketone were dispersed in a sand mill for 5 hours to prepare a charge generation layer liquid.

5. Charge transport layer liquid 500 parts of charge transport material, polycarbonate (TS205
0 Teijin Chemicals Ltd.) 740 parts, antioxidant (IRGAN)
OX1010 10 parts of Irganox Co., Ltd. and silicone oil (KF-54 Shin-Etsu Silicon Co., Ltd.) were dissolved in 5000 parts of dichloromethane, and then filtered through a filter having a roughness of 2.5 μm to prepare a charge transport layer liquid.

Example 1 An intermediate layer liquid was applied on a conductive substrate by a dip coating method to form an intermediate layer having a thickness of 0.3 μm.

Next, the charge generation layer liquid 1 was applied on the intermediate layer by a dip coating method to form a 0.5 μm thick load generation layer. Further, a charge transport layer solution was applied on the charge generation layer by a dip coating method, and dried at 100 ° C. for 60 minutes to form a charge transport layer having a thickness of 24 μm.

Example 2 A sample was prepared in the same manner as in Example 1 except that the charge generation material used in the charge generation layer 1 was changed to the hybrid pigment particles of Synthesis Example 2.

Example 3 A sample was prepared in the same manner as in Example 1 except that the charge generation material used in the charge generation layer 1 was changed to the hybrid pigment particles of Synthesis Example 3.

Example 4 A battery was prepared in the same manner as in Example 1 except that the charge generation material used in the charge generation layer 1 was changed to the hybrid pigment particles of Synthesis Example 4.

Example 5 A battery was prepared in the same manner as in Example 1 except that the charge generation material used in the charge generation layer 1 was changed to the hybrid pigment particles of Synthesis Example 5.

Comparative Example 1 The procedure of Example 1 was repeated except that the charge generating material used in the charge generating layer 1 was changed to the hybrid pigment particles of Synthesis Example 6.

Comparative Example 2 The procedure of Example 1 was repeated, except that the charge generating substance used in the charge generating layer 1 was changed to the hybrid pigment particles of Synthesis Example 7.

Comparative Example 3 A battery was prepared in the same manner as in Example 1 except that the charge generating substance used in the charge generating layer 1 was particles of the compound (1).

Comparative Example 4 The charge generation layer liquid 1 was used as the charge generation layer liquid 2 and the film thickness was 0.25 μm.
Except having set it as m, it produced similarly to Example 1.

Comparative Example 5 Production was carried out in the same manner as in Example 1 except that the charge generating material used for the charge generating layer 1 was a 99: 1 mixture of compound (1) and titanyl phthalocyanine pigment (different from hybrid). did.

Comparative Example 6 Production was carried out in the same manner as in Example 1 except that the charge generating material used for the charge generating layer 1 was a 99: 1 mixture of the compound (1) and a vanadium phthalocyanine pigment (different from a hybrid). did.

Evaluation 1 The electrophotographic photosensitive member obtained as described above was mounted on the color image forming apparatus shown in FIG.

This image forming apparatus uses a digital writing image forming process using a laser light source to form a multicolor superimposed toner image on an electrophotographic photosensitive member, and collectively transfers the toner image to a transfer material. Voltage -80
It is charged by a scorotron charger of 0 V, and forms a multicolor superimposed image by rotating the drum four times using a semiconductor laser of 680 nm. In this process, a halftone image was evaluated after continuous printing of 10,000 sheets in a pattern of a white background (no laser writing) and a green (double exposure of laser) pattern, and the memory resistance was evaluated.

In the same pattern as the image evaluation, 5
The change in the surface potential when 0000 sheets were printed was observed.

Evaluation result Image evaluation × Density decrease in writing area (negative memory) ● Density increase in writing area (positive memory) ○ No memory generated Potential stability ↑ indicates potential increase from the beginning of evaluation Indicates potential drop × Large potential fluctuation ○ Small potential fluctuation

[0107]

[Table 1]

The electrophotographic photoreceptors of Examples 1 to 5 did not cause image memory and maintained a good image. On the other hand, as is apparent from Comparative Examples 1 and 2, pigment particles having no metal atom were used. Even when the hybrid was used, the result was the same as that of Comparative Example 3 without the hybrid, and there was no effect of stabilizing the potential, and an image memory was generated.

In Comparative Example 4 in which the charge generating substance was titanyl phthalocyanine, the VH of the exposed portion was greatly reduced, and a positive memory was generated.

In Comparative Examples 5 and 6, in which the pigment particles having metal atoms were simply mixed, there was no effect of stabilizing the potential and a negative memory was generated, and the effect of stabilizing the potential was exhibited by hybridization. It was the result which supported.

Evaluation 2 The electrophotographic photosensitive member obtained as described above was mounted on a color image forming apparatus shown in FIG.

The color image forming apparatus shown in FIG. 2 is a tandem type color image forming apparatus using an intermediate transfer member. The peripheral portion of a transfer belt 14a as an intermediate transfer member has yellow (Y) and magenta (M ), Cyan (C) and black (K) are provided, and each process unit 100 forms Y, M, C, and K toner images using light and dark toners. Then, the toner image is superimposed and transferred on the transfer belt 14a,
The transferred color toner image is collectively transferred onto a recording sheet as a transfer material, fixed, and discharged outside the apparatus.

Since all four process units 100 have a common structure, only one of them will be described. The photoreceptor drum 10 as an image forming body includes a light-transmitting conductive layer and an organic photosensitive layer (OPC) on the outer periphery of a cylindrical base formed of a light-transmitting member such as glass or light-transmitting acrylic resin. Is formed.

The photosensitive drum 10 is rotated in the counterclockwise direction indicated by an arrow with the light-transmitting conductive layer grounded by power from a driving source (not shown) or driven by the transfer belt 14a.

Reference numerals 11A and 11B both denote scorotron chargers as charging means, which are mounted so as to face and be close to the photosensitive drum 10 in a direction perpendicular to the direction of movement of the photosensitive drum 10, and have a corona having the same polarity as the toner. A uniform potential is applied to the photosensitive drum 10 by the discharge.

The exposure optical systems 12 (L) and 12 (H)
Each is a linear exposure element (not shown) in which a plurality of LEDs (light emitting diodes) as light emitting elements for image exposure are arranged in an array in parallel with the axis of the photosensitive drum 10 and a selfoc as an equal-magnification imaging element. A lens (not shown) is configured as an exposure unit attached to a holder. Exposure optical systems 12 (L) and 12 (H) are attached to a cylindrical holding member and housed inside the base of the photosensitive drum 10. In addition, as the exposure element, a linear element in which a plurality of light emitting elements such as FL (phosphor emission), EL (electroluminescence), and PL (plasma discharge) are arranged in an array is used. Reference numeral 12 (L) denotes an image exposure unit that performs image exposure using image data for light toner, and 12 (H) denotes an image exposure unit that performs image exposure using image data for dark toner.

The exposure optical system 12 (L), which is an image exposing means for light toner, is provided with a scorotron charger 11 A and a developing device 13 having light toner built therein.
Between (L) and the developing unit 13 (L), the photosensitive drum 10 is disposed inside the photosensitive drum 10 in a state provided on the upstream side in the rotation direction of the photosensitive drum 10. The exposure position of the exposure optical system 12 (H), which is an image exposure means for dark toner, on the photosensitive drum 10 is on the downstream side of the developing device 13 (H), and incorporates a scorotron charger 11 B and dark toner. Developing device 13
(H), the photosensitive drum 1 is provided on the upstream side in the rotation direction of the photosensitive drum 10 with respect to the developing device 13 (H).
0.

The developing device 13 (L) is a developing device which contains a one-component light toner or a two-component developer of a light toner and a magnetic carrier and performs reversal development by contact or non-contact. The developing device 13 (H) incorporates a one-component dark toner or a two-component developer of a dark toner and a magnetic carrier, which enables superposition development without destroying the toner image, and performs soft development or more preferably non-development. This is a developing device that performs reversal development by contact development.

In forming an image, the image data of each color of Y, M, C, and K is divided into image data for light toner and image data for dark toner, and the image data for light toner is exposed to the exposure optical system 12 ( L) performs image exposure, and the developing unit 13 (L) performs development using light toner. The image data for the dark toner is subjected to image exposure by the exposure optical system 12 (H), and is developed by the dark toner by the developing device 13 (H). An image is formed on the photosensitive drum 10 so as to overlap. This toner image is transferred onto a transfer belt 14a described later at a transfer position. The transfer residual toner remaining on the drum after the transfer is cleaned by a cleaning device 19 that electrostatically collects the toner.

Process unit 1 of Y, M, C, K colors
The transfer belt 14a, on which the transfer belts 00 and 00 are opposed in parallel, includes a driving roller 14d, a driven roller 14e, and a tension roller 14k.
When the image is formed, the driving roller 14d is rotated by a driving motor (not shown).
The transfer belt 1 is transferred to the photosensitive drum 10 by the next transfer device 14c.
4a is pressed, and the transfer belt 14a is rotated in the direction shown by the arrow in the figure.

A primary transfer device 14c, which is a transfer roller for each color, is provided to face the photosensitive drum 10 for each color with the transfer belt 14a interposed therebetween, and the transfer belt 14a and the photosensitive member for each color are provided. A transfer area (no reference numeral) for each color is formed between the transfer area and the drum 10. Primary transfer unit 14 for each color
By applying a DC voltage having a polarity opposite to that of the toner (positive polarity in this embodiment) to c, and forming a transfer electric field in the transfer area, the toner image on the photosensitive drum 10 for each color is transferred onto the transfer belt 14a. Transfer to

The static eliminator 14m, which is a static eliminator for each color,
Preferably, the primary transfer unit 1 is constituted by a corona discharger.
The transfer belt 14a charged by 4c is neutralized.

A black (K) process unit 1 is started by starting a photoconductor drive motor (not shown) by starting image recording.
00 is rotated in the direction indicated by the arrow in the figure, and at the same time, the application of the potential to the K photoconductor drum 10 is started by the charging action of the K scorotron charger 11A.

After the K photosensitive drum 10 is applied with a potential, the first color signal, that is, the electric signal corresponding to the K light toner image data is exposed by the K light toner exposure optical system 12 (L). Is started, and an electrostatic latent image for light toner corresponding to the K image of the original image is formed on the surface of the K photosensitive drum 10.

The latent image for light toner is subjected to reversal development in a contact state by a developing device 13 (L) for light toner of K, and a toner image of light toner of K is formed in accordance with the rotation of the photosensitive drum 10 of K. It is formed. Then the scorotron charger 11
B and the exposure optical system 12 for the dark toner of K
(H), an electrostatic latent image for dark toner corresponding to the image of K is formed, and the developing device 13 (H) for dark toner forms the K latent image.
Is formed on the previously formed toner image of the light K toner.

The K toner image formed of the light and dark toners formed on the K photoreceptor drum 10 as the image forming body by the above-described image forming process is the first toner image in the K transfer area (no sign). The image is transferred onto the transfer belt 14a by a K primary transfer device 14c as a transfer unit.

Next, the transfer belt 14a is synchronized with the C toner image, and the cyan (C) process unit 10
0, the light color of C formed on the photosensitive drum 10 of C,
Toner image composed of dark toner is C transfer area (no sign)
, The primary transfer device 14c of C as the first transfer means
As a result, a toner image composed of light and dark toners C is superposed on the toner image composed of light and dark toners K.

By the same process, the image is synchronized with the K and C superposed toner images, and the M by the third color signal formed on the M photoconductor drum 10 by the magenta (M) process unit 100. M corresponding to the image data of
In the M transfer area (no symbol), the M primary transfer unit 14c, which is the first transfer means, transfers the M toner images of the K and C toner images from above the K and C toner images. A toner image composed of light and dark toners is formed by being superimposed, synchronized with the superimposed toner images of K, C, and M.
The toner image formed of the light and dark toners of Y corresponding to the image data of Y based on the fourth color signal is formed on the photosensitive drum 10 of the first color in the Y transfer area (no sign). By the Y primary transfer device 14c, a toner image composed of light and dark toners of Y is superimposed on the K, C and M toner images, and the transfer belt 14a
A superimposed color toner image of K, C, M and Y is formed thereon.

The transfer residual toner remaining on the peripheral surface of the photosensitive drum 10 for each color after the transfer is cleaned by a cleaning device 19 which is a cleaning means of the image forming body for each color.

The recording paper P is transferred from the paper supply cassette 15 as a transfer material storage means via a timing roller 16 as a transfer material supply means in synchronization with the formation of the superimposed color toner image on the transfer belt 14a. The superimposed color toner image on the transfer belt 14a is recorded by the secondary transfer device 14g, which is conveyed to a transfer area (no symbol) of the secondary transfer device 14g, which is a unit, and to which a DC voltage having a polarity opposite to that of the toner is applied. It is transferred onto the paper P at once.

The recording paper P on which the color toner image has been transferred is
The charge is removed by a charge removing electrode 16b, which is a separating means formed of a sawtooth electrode plate, conveyed to the fixing device 17, and heat and pressure are applied between the fixing roller 17a and the pressure roller 17b, so that the recording paper P After the toner image is fixed,
It is discharged to a tray outside the device.

The untransferred toner remaining on the peripheral surface of the transfer belt 14a after the transfer is cleaned by a cleaning device 19a which is a transfer belt cleaning means provided opposite to the driven roller 14e across the transfer belt 14a. .

This image forming apparatus uses a digital writing image forming process using a laser light source, forms a multicolor superimposed toner image on an electrophotographic photosensitive member, and collectively transfers the toner image onto a transfer material. Voltage -800
It is charged with a V scorotron charger and uses a 680 nm semiconductor laser.

A major difference from the image forming apparatus used in Evaluation 1 is that a plurality of chargers and a plurality of writing units are provided for forming a multi-color superimposed image by one rotation of the drum.

In this process, a halftone image was evaluated after continuous printing 10000 with a pattern of white background (no laser writing) and green (double exposure of laser) to evaluate memory resistance.

In addition, the same pattern as in this image evaluation
The change in the surface potential when 0000 sheets were printed was observed.

Evaluation results Image evaluation × Density decrease in writing area (negative memory) ● Density increase in writing area (positive memory) ○ No memory generated Potential stability ↑ indicates potential increase from the beginning of evaluation Indicates potential drop × Large potential fluctuation ○ Small potential fluctuation

[0138]

[Table 2]

The electrophotographic photoreceptors of Examples 1, 3, and 4 had no image memory and maintained a good image, whereas the electrophotographic photoreceptors of Comparative Example 2 were mixed with the pigment particles having no metal atoms of Comparative Example 2. The result was the same as that of Comparative Example 3 with no hybridization, without the effect of potential stabilization, and an image memory was generated.

In Comparative Example 4 in which the charge generating substance was titanyl phthalocyanine, the VH of the exposed portion was greatly reduced, and a positive memory was generated.

In Comparative Example 5 in which the pigment particles were mixed with pigment particles having a metal atom, the effect of stabilizing the potential was not obtained, and a negative memory was generated, which proved that the effect of stabilizing the potential was exhibited by the hybridization.

Example 6 A conductive layer liquid was applied onto the substrate 2 by a dip coating method.
Drying at 30 ° C. for 30 minutes gave a conductive layer having a thickness of 0.5 μm.

Next, the intermediate layer liquid 1 was applied on the conductive layer by a dip coating method to form an intermediate layer having a thickness of 0.5 μm.

Next, the charge generation layer solution 1 was applied on the intermediate layer by a dip coating method to form an intermediate layer having a thickness of 0.5 μm.

Next, a charge transport layer solution was applied on the charge generation layer by a dip coating method, and dried at 100 ° C. for 60 minutes to form a charge transport layer having a thickness of 24 μm.

Comparative Example 7 A sample was produced in the same manner as in Example 6 except that the charge generating material used for the charge generating layer 1 was compound 1 particles.

Comparative Example 8 The charge generation layer liquid 1 was used as the charge generation layer liquid 2, and the film thickness was 0.25 μm.
Except having set it as m, it produced similarly to Example 6.

Comparative Example 9 A battery was prepared in the same manner as in Example 6 except that the charge generating material used in the charge generating layer 1 was a 99: 1 mixture of compound 1 and titanyl phthalocyanine pigment (different from hybrid).

Evaluation 3 The electrophotographic photosensitive member obtained as described above was mounted on a color image forming apparatus shown in FIG.

The color image forming apparatus shown in FIG. 3 includes a process unit 100L for forming a color image using light toner on the periphery of the transfer belt 14a and a process unit 100L for forming a color image using dark toner. ,
A process unit 100H for forming a color image using dark toner is arranged in parallel. Since the process units 100L and 100H have a common structure,
The process unit 100L will be described. Y, M, C, and K are arranged from the upstream side in the rotation direction along the photosensitive drum 10.
Scorotron charger 1 as charging means for four colors
1. Four sets of an exposure optical system 12 (L) and a developing unit 13 (L) are provided. The photosensitive drum 10 whose peripheral surface has been cleaned by the cleaning device 19 is uniformly charged by the scorotron charger 11Y, and is further exposed to light toner by the exposure optical system 12 (L) Y based on Y image data for light toner. A latent electrostatic image of Y is formed, and a developing device 13 (L) Y containing a light toner forms a Y toner image with the light toner.

On the Y toner image of the light toner, an M toner image of the light toner is superposed by the scorotron charger 11M, the exposure optical system 12 (L) M, and the developing device 13 (L) M. Further, a scorotron charger 11C, an exposure optical system 12
(L) C, a C toner image of light toner is superposed by the developing unit 13 (L) C, and a scorotron charger 11K, an exposure optical system 12 (L) K, and a developing unit 13 are formed thereon.
(L) The K toner image of light toner is superimposed and formed by K.

Similarly, for the process unit 100H, Y, M, C,
A scorotron charger 11 for K4 color, an exposure optical system 12 (H) for exposing an image based on image data for dark toner, and a developing device 13 (H) containing dark toner, all of Y, M, C using dark toner. , K4 color toner images are superposed.

The color toner image formed of the light toner formed on the process unit 100L is transferred onto the transfer belt 14a by the primary transfer device 14c, and is transferred to the transfer belt 14a.
The color toner image of the dark toner formed on the process unit 100H is transferred onto the color toner image of the light toner transferred thereon so as to overlap. Light transferred by being superimposed on the transfer belt 14a,
The color toner image of the dark toner is
The sheet is collectively transferred by a secondary transfer unit 14g onto a recording sheet P fed through the printer 6 and is discharged by a discharging electrode 16b. Thereafter, the sheet is fixed by a fixing device 17 and discharged to the outside of the device.

This image forming apparatus employs a digital writing image forming process using an LED light source to form a multicolor superimposed toner image on an electrophotographic photosensitive member and collectively transfer the toner image onto a transfer material. Voltage -800V
And a 645 nm LED light source. The major difference from the image forming apparatus used in Evaluation 2 is that an LED exposing device is disposed inside the photoconductor.

In this process, a halftone image was evaluated after continuous printing of 1,000 sheets in a pattern of white background (no laser writing) and green (double exposure of laser) to evaluate the memory resistance.

Further, a change in the surface potential (after 2,000 sheets) when the device was operated in the same pattern as in the image evaluation was observed.

Evaluation result Image evaluation × Density decrease in writing area (negative memory) ● Density increase in writing area (positive memory) ○ No memory generation Potential stability ↑ indicates potential increase from the beginning of evaluation Indicates potential drop × Large potential fluctuation ○ Small potential fluctuation

[0158]

[Table 3]

The electrophotographic photoreceptor of Example 6 had no image memory and maintained a good image. On the other hand, the electrophotographic photoreceptor obtained by mixing the pigment particles having no metal atom of Comparative Example 7 had no hybridization. As a result, the effect of stabilizing the potential was not obtained, and an image memory was generated.

In Comparative Example 8 in which the charge generating substance was titanyl phthalocyanine, the VH of the exposed portion was greatly reduced, and a positive memory was generated.

In Comparative Example 9 where the pigment particles were mixed with pigment particles having metal atoms, there was no effect of stabilizing the potential, and the result proved that a negative memory was generated and the effect of stabilizing the potential was exhibited by hybridization.

As can be seen from the results of Evaluations 1 to 3, the electrophotographic photoreceptor of the present invention is provided with a single or plural digital exposure devices outside or inside the electrophotographic photoreceptor, and forms a multicolor image on the photoreceptor by development. An electrophotographic image forming method that forms a superimposed image and collectively transfers it to a transfer material. The electrophotographic image forming method shows excellent results in potential and image stability even when used for a long time. It can be seen that it is.

[0163]

According to the present invention, in an image forming process for forming a multi-color superimposed image of two or more colors on an electrophotographic photosensitive member, a change in potential performance with respect to an exposure history even when used for a long time for image formation. It is possible to provide an electrophotographic photosensitive member that is small and does not cause image defects, an image forming method, an image forming apparatus, and a process cartridge.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an image forming apparatus according to the present invention.

FIG. 2 is a cross-sectional view of the image forming apparatus according to the present invention.

FIG. 3 is a sectional view of the image forming apparatus according to the present invention.

[Explanation of symbols]

Reference Signs List 10 photoconductor drum (electrophotographic photoconductor, photoconductor) 11 charger 12 image exposure device (exposure optical system) 13 developing device 16 paper feed roller (timing roller) 17 fixing device 18 transfer roller (transfer device) 19 cleaning device ( Cleaning device) 21 Discharge roller 30 Removable process cartridge in which photoconductor, charging device, transfer device / separator, and cleaning device are integrated.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Chigusa Miyake 2970, Ishikawacho, Hachioji-shi, Tokyo Konica Corporation F-term (reference) 2H068 AA19 BA36 BA39 BA40 FA01 FA07 FA12 FB08 FB13

Claims (8)

[Claims] 1. A single electrophotographic photosensitive member uniformly charged is image-exposed by a digital exposure device, and the formed electrostatic latent image is developed by a plurality of developing devices arranged on the periphery of the photosensitive member. In an electrophotographic photoreceptor used for an image forming method of forming a multicolor superimposed image on a photoreceptor and collectively transferring it to a transfer material, a metal atom is contained in an aromatic diamine condensate compound particle of a polycyclic anhydride. An electrophotographic photoreceptor using pigment particles obtained by mixing a compound containing 2. The electrophotographic photoreceptor according to claim 1, wherein the aromatic diamine condensate compound of the polycyclic anhydride is a bisimidazole perylene compound represented by the following compound (1). Embedded image 3. The electrophotographic photosensitive member according to claim 1, wherein the pigment particles obtained by containing a metal atom are a metal phthalocyanine compound. 4. An aromatic diamine condensate compound of a polycyclic anhydride is a bisimidazole perylene compound represented by the above compound (1), and pigment particles obtained by containing a metal atom are metal phthalocyanine compounds. The electrophotographic photosensitive member according to claim 1, wherein: 5. The electrophotographic photoreceptor according to claim 4, wherein the concentration of the mixed metal phthalocyanine is in the range of 0.2 to 10% by mass. 6. A single electrophotographic photoreceptor uniformly charged is image-exposed by a digital exposure device, and the formed electrostatic latent image is developed by a plurality of developing devices arranged on the periphery of the photoreceptor. In the image forming method of forming a multicolor superimposed image on a photoreceptor and collectively transferring it to a transfer material, the electrophotographic photoreceptor contains a metal atom in an aromatic diamine condensate compound particle of a polycyclic anhydride. An image forming method comprising using pigment particles obtained by mixing the above compound. 7. A uniformly charged single electrophotographic photosensitive member is image-exposed by a digital exposure device, and the formed electrostatic latent image is developed by a plurality of developing devices arranged around the periphery of the photosensitive member. In an image forming apparatus that forms a multicolor superimposed image on a photoreceptor and collectively transfers the image onto a transfer material, the electrophotographic photoreceptor contains metal atoms in aromatic diamine condensate compound particles of a polycyclic anhydride. An image forming apparatus using pigment particles obtained by mixing the above compound. 8. An image forming apparatus according to claim 7, wherein at least an electrophotographic photosensitive member and at least one of a uniform charger, a developing device, a transfer / separator, and a cleaning device are integrally combined. A process cartridge.