JP2002214816A - Laminated electrophotographic photoreceptor, image forming method and image forming device using the same, and process cartridge for the image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor applied to a digital high-speed electrophotographic process and superior in wear resistance. SOLUTION: In this laminated electrophotographic photoreceptor, where at least a charge generating layer, a charge transporting layer and a protective layer are formed on a conductive substrate, filler is incorporated in the protective layer. The filler has a peak at 0.2 to 0.3 μm in particle size distribution, including secondary particles, and the filler having particle size of >=0.3 μm exists more on the surface layer side than on the substrate side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated electrophotographic photoreceptor, an image forming method, an image forming apparatus, and a process cartridge for the image forming apparatus. The present invention relates to a laminated electrophotographic photosensitive member having excellent durability and capable of obtaining a stable image, an image forming method using the electrophotographic photosensitive member, an image forming apparatus, and a process cartridge for the image forming apparatus.

[0002]

2. Description of the Related Art The electrophotographic method using the Carlson process and various modified processes of this process has been widely used in copiers,
Widely used in electrophotographic devices such as facsimile machines and printers. As an electrophotographic photoreceptor (hereinafter, may be simply referred to as a photoreceptor) used in the electrophotographic method,
In recent years, organic photosensitive materials have been widely used because of their advantages such as low cost, mass productivity, and no pollution.

The mechanism of the formation of an electrostatic latent image on a photoreceptor is as follows. When a photoreceptor is charged and irradiated with light, light is absorbed by a charge generation material, and the charge generation material that absorbed the light generates charge carriers. The charge carriers are injected into the charge transporting material, move in the charge transporting layer (or the photosensitive layer) according to the electric field generated by the charging, and neutralize the charge on the photoreceptor surface to form an electrostatic latent image. It is to do.

As an organic photoreceptor, a photoconductive resin represented by polyvinyl carbazole (PVK) is used, and in addition, 2,4,7-trinitrofluorenone (TNF) is used.
-A charge transfer complex type represented by PVK; a pigment dispersion type represented by phthalocyanine-binder; a function-separated type photoreceptor using a combination of a charge generating substance and a charge transporting substance; Attention has been paid to a separation type photoconductor, and it has been put to practical use.

Various types of organic photoreceptor materials have been developed in the past, but in order to make these excellent photoreceptors that can be put to practical use, sensitivity, accepting potential, potential holding property, potential stability, Various characteristics are required such as electrophotographic characteristics such as residual potential and spectral characteristics, mechanical durability such as abrasion resistance, and chemical stability against heat, light, and discharge products. In particular, as the size of the electrophotographic system is reduced, the diameter of the photoconductor is inevitably reduced, and the demand for the durability of the photoconductor, which progresses according to the number of sheets passed, is increasing. .

As described above, there has been a strong demand for mechanical durability mainly including abrasion resistance. However, in a conventional organic photoreceptor (OPC) and an electrophotographic process using the same, the organic photoreceptor (OPC) has a high resistance to organic substances. At present, sufficient durability has not been obtained due to low wear properties. Further, it is clear that the requirement for abrasion resistance is that thinning of the photosensitive layer is indispensable for higher definition of an output image, and the margin for abrasion is becoming stricter.

The reason why the thickness of the photosensitive layer has a particularly large effect on the high definition of the output image is considered as follows. For example,
In the case of the stacked negatively charged OPC, electrons of the positive and negative carriers generated in the charge generation layer by the exposure light are absorbed by the substrate, but the holes move through the charge transport layer and recombine with the electrons on the photoreceptor surface. Disappear. Due to this annihilation, the electric field that pulls the hole up to the surface of the photoreceptor gradually weakens, and the hole moves toward a region not exposed to light. This is called a diffusion phenomenon of the carrier in the direction of the surface of the photoreceptor, which hinders formation of a latent image faithful to the exposure light and causes image deterioration such as a reduction in resolution. In this diffusion phenomenon, the thickness of the charge transport layer has a great influence, and reducing the thickness is very effective for maintaining the resolution. Further, in the laser exposure that has recently become mainstream, unlike the exposure exposure, such as a conventional halogen lamp, incident photons flow rate in relation to the exposure, as compared with the case of the halogen lamp, about ¹⁰⁷ times larger. As a result, the generated carrier density becomes extremely large, and the electric charge flowing into the charge transport layer weakens the electric field of the charge generation layer, affecting the carrier moving speed and causing the carrier generated near the center of the laser beam to reach the photoconductor surface. The arrival is also delayed. The space charge distribution generated in this manner makes it easy for carriers to diffuse in the direction parallel to the surface of the photoreceptor, and the influence on the resolution is further increased.

Japanese Patent Application Laid-Open No. Sho 57-30846 discloses a method for improving the abrasion resistance of an organic photoreceptor by providing a protective layer containing a filler made of metal or metal oxide. . This method
The average particle size of the filler is set to 0.3 μm or less to increase the transparency of the protective layer and to suppress an increase in the residual potential. Further, a method of including a charge transport material together with a filler in a protective layer is disclosed in Japanese Patent Application Laid-Open No. 4-281461, and it is stated that a rise in residual potential can be suppressed while maintaining abrasion resistance. Furthermore, JP-A-53-133444 and JP-A-55-157748 disclose a protective layer containing an organic acid together with a filler in the protective layer to suppress the rise in residual potential. Japanese Unexamined Patent Publication No.
No. -4275. Also, JP-A-8-23
No. 4455, in a charge transporting layer containing a filler, a difference in refractive index between the filler and the charge transporting layer is 0.1 or more, and particles having a particle diameter of 1 to ³ μm per 1 mm ^{2 are} 1 × 10 ^4.
One containing 2 to 10 ⁵ is disclosed.

However, organic photoreceptors employing these methods have good abrasion resistance, but are liable to cause filming due to toner components and the like, and have good dispersibility of the filler in the protective layer. Aggregates that do not result in poor adhesion of the cleaning blade to easily cause poor cleaning, and also have a negative effect on the electrostatic stability and durability of the photoreceptor. In fact, the desired characteristics have not been obtained.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a laminated electrophotographic photosensitive member capable of realizing a stable and highly durable high-speed electrophotographic process, an image forming method using the electrophotographic photosensitive member, and an image forming method. It is an object of the present invention to provide an apparatus and a process cartridge for an image forming apparatus. That is, an object of the present invention is to provide an electrophotographic photosensitive member that can be suitably used in a high-durability digital high-speed electrophotographic process using a laser, which has become a mainstream in recent years, as a writing light source. The purpose of the present invention is to provide a photoreceptor having excellent mechanical durability, which has no adverse effect, and also has a problem in thinning a photoreceptor intended to increase the definition of an output image. It is an object of the present invention to provide an image forming method, an image forming apparatus, and a process cartridge for an image forming apparatus, which do not cause an abnormal image such as an image deletion seen in an optical body and have excellent mechanical durability. .

[0011]

Means for Solving the Problems As a result of repeated studies to achieve the above object, the present inventors have found that the protective layer of the photoreceptor contains a filler and the form of the filler in the protective layer is determined. It has been found that by setting it constant, a photosensitive member having excellent durability against a high-speed electrophotographic process and having excellent wear resistance can be obtained, and the present invention has been completed. Further, by supplying a lubricant on the protective layer, it is possible to suppress filming in a state where the abrasion resistance is good. The toner adhesion to the body and the repetition of the toner collection operation in the cleaning section have the effect of suppressing image flow while maintaining abrasion resistance. By applying a voltage in which an AC component is superimposed on a DC component to a charging member, it is possible to maintain a good charging performance and achieve a smaller charging device and a longer life by applying a voltage superimposed on a DC component to the photoconductor. They have found that they can do this and have completed the present invention.

That is, according to the present invention, the following electrophotographic photosensitive member, image forming method, image forming apparatus, and process cartridge for the image forming apparatus are provided.

(1) In a laminated electrophotographic photosensitive member having at least a charge generation layer, a charge transport layer and a protective layer formed on a conductive substrate, the protective layer contains a filler, and the filler is composed of secondary particles. In the particle size distribution containing
A layered electrophotographic photosensitive member having a peak at 0.3 μm and having a larger amount of filler having a particle size of 0.3 μm or more on the surface layer side than on the conductive substrate side.

(2) In the laminated electrophotographic photosensitive member according to the above (1), the filler content in an arbitrary cross section in a direction perpendicular to the substrate of the protective layer is 3 to 5% as an area occupancy in the plane. A laminated electrophotographic photosensitive member, characterized in that:

(3) In the laminated electrophotographic photosensitive member as described in (2) above, the area occupied by the filler having a particle size of 0.3 μm or more in an arbitrary cross section perpendicular to the substrate of the protective layer is in the plane. 10-30% of total filler occupation area
A laminated electrophotographic photosensitive member, characterized in that:

(4) At least charging, image exposure, development,
An image forming method which performs transfer, fixing, and cleaning processes, wherein the multilayer electrophotographic photoreceptor according to any one of the above (1) to (3) is used.

(5) The image forming method as described in (4) above, wherein a lubricant is supplied and applied to the surface of the photoreceptor.

(6) The image forming method according to (4) or (5), wherein the toner supplied to the developing section contains a powdery lubricant.

(7) In the image forming method according to any one of the above (4) to (6), when a non-image is formed, a step of adhering toner from the developing section to the surface of the photoreceptor and the cleaning section are performed on the photoreceptor. The step of collecting the toner is repeated to clean the surface of the photoreceptor.

(8) At least charging, image exposure, development,
An image forming apparatus having a transfer, fixing and cleaning means, comprising the laminated electrophotographic photosensitive member according to any one of (1) to (3).

(9) The image forming apparatus according to (8), further comprising means for supplying and applying a lubricant to the surface of the photoreceptor.

(10) The image forming apparatus according to (8) or (9), wherein the developing means contains a powdery lubricant in the toner supplied to the developing section.

(11) In the image forming apparatus according to any one of the above (8) to (10), at the time of non-image formation, a step of adhering toner from the developing section to the surface of the photoreceptor, and the cleaning section is performed on the photoreceptor. An image forming apparatus comprising: a photoconductor cleaning unit that repeatedly performs a step of collecting the toner.

(12) In a process cartridge for an image forming apparatus having at least charging, image exposure, development, transfer, fixing and cleaning means, (1) to (3)
A process cartridge for an image forming apparatus, comprising the laminated electrophotographic photosensitive member according to any one of the above.

(13) The process cartridge for an image forming apparatus according to the above (12), further comprising means for supplying and applying a lubricant to the surface of the photoreceptor.

(14) In the process cartridge for an image forming apparatus according to the above (12) or (13), the image is characterized in that the developing means contains a powdery lubricant in the toner supplied to the developing section. Process cartridge for forming equipment.

(15) In the process cartridge for an image forming apparatus according to any one of the above (12) to (14), the step of applying toner from the developing unit to the surface of the photoreceptor during non-image formation and the cleaning unit perform the photosensitive operation. A process cartridge for an image forming apparatus, comprising: a photoconductor cleaning means for repeatedly performing a process of collecting toner on a body.

(16) In the image forming method, the image forming apparatus or the process cartridge for the image forming apparatus according to any one of the above (4) to (15), the charging means for the photosensitive member contacts or contacts the photosensitive member. An image forming method, an image forming apparatus, or a process cartridge for an image forming apparatus, wherein the image forming apparatus and the process cartridge are arranged close to each other.

(17) In the image forming method, the image forming apparatus or the process cartridge for the image forming apparatus according to the above (16), the photosensitive member is exposed to light by applying a voltage in which an AC component is superimposed on a DC component to the charging member. An image forming method, an image forming apparatus, or a process cartridge for an image forming apparatus, wherein a body is charged.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the drawings. FIG. 1 is a schematic sectional view of the laminated electrophotographic photosensitive member of the present invention. FIG. 2 is a schematic sectional view of another laminated electrophotographic photosensitive member of the present invention. In the electrophotographic photoreceptor of the present invention, a photosensitive layer 2 is provided on a conductive support (conductive substrate) 1. The photosensitive layer 2 includes a charge generation layer 3 mainly composed of a charge generation material and a charge transport layer. It is formed by lamination with the charge transport layer 4 mainly composed of a material. Then, in the present invention, a protective layer 5 is formed as a surface layer of such an electrophotographic photosensitive member. This protective layer 5 will be described later.

The conductive support 1 has a volume resistance of 10 ¹⁰ Ωcm.
Those exhibiting the following conductivity, for example, metals such as aluminum, nickel, chromium, nichrome, copper, silver, gold, platinum,
Metal oxides such as tin oxide and indium oxide, by vapor deposition or sputtering, film or cylindrical plastic, coated on paper, aluminum, aluminum alloy, nickel, stainless steel, etc. It consists of a tube or the like whose surface has been treated by cutting, superfinishing, polishing or the like.

The charge generation layer 3 is a layer containing a charge generation material as a main component. Inorganic or organic materials are used for the charge generating material, and typical examples thereof include monoazo pigments, disazo pigments, trisazo pigments, perylene pigments, perinone pigments, quinacridone pigments, quinone condensed polycyclic compounds, and squaric. Examples include acid dyes, phthalocyanine pigments, naphthalocyanine pigments, azulhenium salt dyes, selenium, selenium-tellurium alloys, selenium-arsenic alloys, and amorphous silicon. These charge generation materials may be used alone or in combination of two or more.

The charge generating layer 3 is prepared by dispersing the charge generating material with a binder resin and a solvent such as tetrahydrofuran, cyclohexanone, dioxane, 2-butanone and dichloroethane by a ball mill, an attritor, a sand mill or the like. It can be formed by coating. The coating is performed by a dip coating method, a spray coat, a bead coat method, or the like.

[0034] The binder resins suitably used include polyamide resins, polyurethane resins, polyester resins, epoxy resins, polyketone resins, polycarbonate resins, silicone resins, acrylic resins, polyvinyl butyral resins, polyvinyl formal resins, polyvinyl ketone resins, and polystyrene. Resin, polyacrylic resin,
Examples thereof include polyamide resins. The amount of the binder resin is 0 to 2 with respect to 1 part of the charge generating material on a weight basis.
The part is appropriate.

The charge generation layer 3 can also be formed by a known vacuum thin film manufacturing method. The thickness of the charge generation layer 3 is usually 0.01 to 5 μm, preferably 0.1 to 2 μm.
m.

The charge transporting layer 4 can be formed by dissolving or dispersing a charge transporting material and a binder resin in a suitable solvent, coating and drying. If necessary, a plasticizer or a leveling agent can be added.

Among the charge transport materials, low-molecular charge transport materials include an electron transport material and a hole transport material.

Examples of the electron transporting material include chloranil, bromanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone. 2,4,5,7-tetranitroxanthone,
2,4,8-trinitrothioxanthone, 2,6,8-
Electron accepting substances such as trinitro-4H-indeno [1,2-b] thiophene-4one and 1,3,7-trinitrodibenzothiophene-5,5-dioxide are exemplified. These electron transporting materials may be used alone,
It may be used as a mixture of more than one species.

Examples of the hole transport material include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4-
Dibenzylaminophenyl) propane, styryl anthracene, styryl pyrazoline, phenylhydrazones,
α-phenylstilbene derivative, thiazole derivative, triazole derivative, phenazine derivative, acridine derivative, benzofuran derivative, benzimidazole derivative,
Electron donating substances such as thiophene derivatives; These hole transport materials may be used alone or as a mixture of two or more.

When a polymer charge transporting material is used as the charge transporting material, the charge transporting layer may be formed by dissolving or dispersing in a suitable solvent, coating and drying. The polymer charge transporting material may be any material as long as the low molecular weight charge transporting material has a charge transporting substituent on the main chain or side chain. Particularly preferred polymeric charge transport materials are polycarbonate, polyurethane, polyester, polyether, and the like,
Among them, use of a polycarbonate having a triarylamine structure is advantageous.

If necessary, an appropriate amount of a binder resin, a low-molecular charge transport material, a plasticizer, a leveling agent, a lubricant and the like can be added to the polymer charge transport material.

The binder resin used in the charge transport layer 4 together with the charge transport material includes polystyrene resin, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester resin, and polystyrene resin. Vinyl chloride resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate resin, polyvinylidene chloride resin, polyarylate resin, phenoxy resin, polycarbonate resin, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral resin, polyvinyl formal resin, polyvinyl toluene Resin, acrylic resin,
Thermoplastic or thermosetting resins such as silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, and alkyd resin are exemplified.

As the plasticizer to be added to the charge transport layer 4 as necessary, general-purpose plasticizers such as dibutyl phthalate and dioctyl phthalate can be used. The amount of the plasticizer used is based on the weight of the binder resin. 0-30%
The degree is appropriate.

Examples of the leveling agent which is added to the charge transport layer 4 as needed include silicone oils such as dimethyl silicone oil and methyl phenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in a side chain. The amount is suitably about 0 to 1% based on the weight of the binder resin.

Examples of the solvent include tetrahydrofuran, dioxane, toluene, 2-butanone, monochlorobenzene, dichloroethane, methylene chloride and the like.

The thickness of the charge transport layer 4 may be appropriately selected in the range of 5 to 30 μm according to desired characteristics of the photosensitive member.

In the present invention, the content of the charge transporting material contained in the photosensitive layer is preferably at least 40% by weight of the charge transporting layer. If the amount is less than 40% by weight, a sufficient light decay time in a high-speed electrophotographic process cannot be obtained in pulse light exposure in laser writing on a photoconductor, which is not preferable.

The mobility of the charge transport layer in the photoreceptor of the present invention is 3 × 10 ⁻⁵ under the conditions of the electric field strength of the charge transport layer in the range of 2.5 × 10 ^{5 to} 5.5 × 10 ⁵ V / cm. cm ² / V ・
s or more, preferably 7 × 10 ⁻⁵ cm ² / V ·
More preferably, it is s or more. The mobility can be adjusted as appropriate to achieve this under each use condition. This mobility is based on a conventionally known TOF (Time Of
(Flight) method.

In the laminated electrophotographic photoreceptor of the present invention, an undercoat layer can be formed between the conductive support 1 and the photosensitive layer. The undercoat layer generally contains a resin as a main component. However, in consideration of applying a photosensitive layer on the undercoat layer using a solvent, the resin is a resin having high resistance to dissolution in a general organic solvent. Is desirable.

Examples of such resins include water-soluble resins such as polyvinyl alcohol resin, casein and sodium polyacrylate, alcohol-soluble resins such as copolymerized nylon and methoxymethylated nylon, polyurethane resins, melamine resins, and alkyd-melamine resins. And a curable resin forming a three-dimensional network structure such as an epoxy resin.

In order to prevent moiré and reduce residual potential, the undercoat layer may be made of titanium oxide, silica, alumina,
Fine powder of a metal oxide such as zirconium oxide, tin oxide, or indium oxide may be added.

This undercoat layer can be formed by using an appropriate solvent and a coating method as in the case of the above-mentioned photosensitive layer.

It is also useful to use a metal oxide layer formed by a sol-gel method or the like using a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like as the undercoat layer. is there. In addition, the undercoat layer may be formed by anodizing Al ₂ O ₃ , an organic substance such as polyparaxylylene (parylene),
An inorganic material such as SiO, SnO ₂ , TiO ₂ , ITO, or CeO ₂ formed by a vacuum thin film manufacturing method is also effective.

The thickness of the undercoat layer is suitably from 0 to 5 μm.

In the laminated electrophotographic photosensitive member of the present invention, a protective layer 5 containing a filler is formed on the photosensitive layer 2 as a surface layer for the purpose of protecting the photosensitive layer and improving durability.

Materials used for the protective layer 5 include:
ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether resin, allyl resin, phenol resin, polyacetal resin, polyamide resin, polyamideimide resin, polyacrylate resin, polyallyl sulfone resin, polybutylene resin, polybutylene Terephthalate resin, polycarbonate resin, polyether sulfone resin, polyethene resin, polyethylene terephthalate resin, polyimide resin, acrylic resin, polymethylpentene resin, polypropylene resin, polyphenylene oxide resin, polysulfone resin, AS resin, AB resin, BS resin, polyurethane resin And resins such as polyvinyl chloride resin, polyvinylidene chloride resin, and epoxy resin.

A filler is added to the protective layer 5 for the purpose of improving abrasion resistance. The filler may be an organic material such as a fluorine resin or a silicone resin such as polytetrafluoroethylene, or a fine powder made of an inorganic material such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide, and potassium titanate. Is mentioned.

The amount of the filler added to the protective layer 5 is usually 10 to 40% by weight, preferably 20 to 3%.
0%. If the amount of the filler is less than 10%, the abrasion is large and the durability is inferior. If the amount exceeds 40%, the potential of the bright portion at the time of exposure becomes remarkably increased, and the decrease in sensitivity cannot be ignored.

Further, a dispersing aid can be added to the protective layer 5 in order to improve the dispersibility of the filler. As the dispersing aid to be added, those used in paints and the like (eg, modified epoxy resin condensate, unsaturated polycarboxylic acid low molecular weight polymer, etc.) can be appropriately used, and the amount thereof is usually the amount of filler contained on a weight basis. 0.5 to 4%, and preferably 1 to 2%.

It is also effective to add the above-mentioned charge transporting material to the protective layer 5, and an antioxidant can be added if necessary. Antioxidants will be described later.

As a method for forming the protective layer 5, a usual coating method such as a spray method is employed. The thickness of the protective layer 5 is 0.5
10 to 10 μm, preferably about 4 to 6 μm is appropriate.

In the present invention, it is important for the abrasion resistance and image characteristics to make the form of the filler in the protective layer constant. In other words, the presence of the filler in the protective layer does not impair the sensitivity and electrostatic stability of the photosensitive layer, does not impair the fineness of exposure, and achieves higher definition and faster response by thinning based on abrasion resistance. Can contribute.

In order to satisfy this requirement, in the present invention, the filler contained in the protective layer has a peak at 0.2 to 0.3 μm in the particle size distribution including the secondary particles, and has a particle size of 0.1 to 0.3 μm. The filler content of 3 μm or more in the surface layer side is larger than that in the substrate side. Preferably, in addition to this, the filler content of the protective layer in an arbitrary cross section perpendicular to the substrate in the plane is increased. The area occupancy is set to 3 to 5%. More preferably, the area occupied by the filler having a particle diameter of 0.3 μm or more in an arbitrary cross section perpendicular to the base of the protective layer is further occupied by all the fillers in the plane. It is 10 to 30% of the area.

As a result of the study by the present inventors, when the value was not within the above range, an increase in residual potential, a decrease in sensitivity, a decrease in resolution, a decrease in abrasion resistance, and the occurrence of an abnormal image due to filming were confirmed. It is considered that the protective layer configuration as described above maintains a desired abrasion resistance, and the abrasion characteristics hardly change with the aging of the cleaning device in the image forming apparatus.

The form of the filler in the protective layer can be controlled by the particle size and distribution of the filler material used, the formulation of the coating solution, and the coating device, and the use of a dispersion aid is effective.

In the present invention, another intermediate layer can be formed between the photosensitive layer and the protective layer. The intermediate layer generally uses a binder resin as a main component. Examples of the binder resin include polyamide resin, alcohol-soluble nylon, water-soluble polyvinyl butyral resin, polyvinyl butyral resin, and polyvinyl alcohol resin.

As the method for forming the intermediate layer, the above-mentioned ordinary coating method is employed. The thickness of the intermediate layer is 0.05 to 2 μm
The degree is appropriate.

In the present invention, each layer is provided with an antioxidant, a plasticizer, a lubricant, an ultraviolet absorber, a low molecular weight compound, for the purpose of improving environmental resistance, especially for preventing a decrease in sensitivity and a rise in residual potential. Charge transport materials and leveling agents can be added.

Examples of the antioxidant that can be added to each layer include the following.

Phenolic compounds: 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol,
n-octadecyl-3- (4-hydroxy-3,5-di-t-butylphenol), 2,2-methylene-bis-
(4-methyl-6-t-butylphenol), 2,2-
Methylene-bis- (4-ethyl-6-t-butylphenol), 4,4-thiobis- (3-methyl-6-t-butylphenol), 4,4-butylidenebis- (3-methyl-6-t-butylphenol) ), 1,1,3-tris- (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6
-Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate] methane, bis [3,3-bis (4-hydroxy-3-t-butylphenyl) butyric acid] glycol ester, tocopherols and the like.

Paraphenylenediamines: N-phenyl-N-isopropyl-p-phenylenediamine, N, N
-Di-sec-butyl-p-phenylenediamine, N-
Phenyl-N-sec-butyl-p-phenylenediamine, N, N-di-isopropyl-p-phenylenediamine, N, N-dimethyl-N, N-di-t-butyl-p-
Phenylenediamine and the like.

Hydroquinones: 2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-
Chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) -5-methylhydroquinone and the like.

Organic sulfur compounds: dilauryl-3,3-
Thiodipropionate, distearyl-3,3-thiodipropionate, ditetradecyl-3,3-thiodipropionate and the like.

Organic phosphorus compounds: triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine and the like.

Examples of the plasticizer that can be added to each layer include the following.

Phosphate ester plasticizers: triphenyl phosphate, tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, trichloroethyl phosphate, cresyl diphenyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate , Triphenyl phosphate and the like.

Phthalate ester plasticizers: dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dibutyl phthalate, diheptyl phthalate, di-2-phthalate
Ethylhexyl, diisooctyl phthalate, di-n-octyl phthalate, dinonyl phthalate, diisononyl phthalate, diisodecyl phthalate, diundecyl phthalate,
Ditridecyl phthalate, dicyclohexyl phthalate, butyl benzyl phthalate, butyl lauryl phthalate, methyl oleyl phthalate, octyl decyl phthalate, dibutyl fumarate, dioctyl fumarate and the like.

Aromatic carboxylate plasticizers: trioctyl trimellitate, tri-n-octyl trimellitate, octyl oxybenzoate and the like.

Aliphatic dibasic ester plasticizers: dibutyl adipate, di-n-hexyl adipate, di-2-ethylhexyl adipate, di-n-octyl adipate, n-octyl adipate-n-octyl Decyl, diisodecyl adipate, dicapryl adipate, di-2-ethylhexyl azelate, dimethyl sebacate, diethyl sebacate, dibutyl sebacate, di-n-sebacate
Octyl, di-2-ethylhexyl sebacate, di-2-ethoxyethyl sebacate, dioctyl succinate,
Diisodecyl succinate, dioctyl tetrahydrophthalate, di-n-octyl tetrahydrophthalate and the like.

Fatty acid ester derivative plasticizers: butyl oleate, glycerin monooleate, methyl acetyl ricinoleate, pentaerythritol ester, dipentaerythritol hexaester, triacetin, tributyrin and the like.

Oxyacid ester plasticizers: methyl acetyl ricinoleate, butyl acetyl ricinoleate, butyl phthalyl butyl glycolate, tributyl acetyl citrate and the like.

Epoxy plasticizers: epoxidized soybean oil, epoxidized linseed oil, butyl epoxystearate, decyl epoxystearate, octyl epoxystearate, benzyl epoxystearate, dioctyl epoxyhexahydrophthalate, epoxyhexahydrophthalic acid Didecyl and the like.

Dihydric alcohol ester plasticizers: diethylene glycol dibenzoate, triethylene glycol di-2-ethyl butyrate and the like.

Chlorinated plasticizers: chlorinated paraffin, chlorinated diphenyl, chlorinated fatty acid methyl, methoxy chlorinated fatty acid methyl and the like.

Polyester plasticizer: polypropylene adipate, polypropylene sebacate, polyester,
Acetylated polyester and the like.

Sulfonic acid derivative plasticizers: p-toluenesulfonamide, o-toluenesulfonamide, p-toluenesulfonethylamide, o-toluenesulfonethylamide, toluenesulfone-N-ethylamide, p
-Toluenesulfone-N-cyclohexylamide and the like.

Citric acid derivative plasticizers: triethyl citrate, triethyl acetyl citrate, tributyl citrate, tributyl acetyl citrate, tri-2-ethylhexyl acetyl citrate, n-octyldecyl acetyl citrate and the like.

Others: terphenyl, partially hydrogenated terphenyl, camphor, 2-nitrodiphenyl, dinonylnaphthalene, methyl abietic acid and the like.

The following can be exemplified as a lubricant that can be added to each layer.

Hydrocarbon compounds: liquid paraffin, paraffin wax, microwax, low-polymerized polyethylene and the like.

Fatty acid compounds: lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid and the like.

Fatty acid amide compounds: stearylamide, palmitylamide, oleinamide, methylenebisstearamide, ethylenebisstearamide and the like.

Ester compounds: lower alcohol esters of fatty acids, polyhydric alcohol esters of fatty acids, polyglycol esters of fatty acids and the like.

Alcohol compounds: cetyl alcohol,
Stearyl alcohol, ethylene glycol, polyethylene glycol, polyglycerol, etc.

Metal soaps: lead stearate, cadmium stearate, barium stearate, calcium stearate, zinc stearate, magnesium stearate and the like.

Natural waxes: carnauba wax, candelilla wax, beeswax, whale wax, Ibota wax, montan wax and the like.

Others: silicone compounds, fluorine compounds, etc.

Examples of the ultraviolet absorber which can be added to each layer include the following.

Benzophenone ultraviolet absorbers: 2-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,2,4-trihydroxybenzophenone,
2,2,4,4-tetrahydroxybenzophenone,
2,2-dihydroxy-4-methoxybenzophenone and the like.

Salicylate ultraviolet absorbers: phenyl salicylate, 2,4-di-t-butylphenyl 3,5-di-t-butyl 4-hydroxybenzoate, etc.

Benzotriazole UV absorber: (2
-Hydroxyphenyl) benzotriazole, (2-hydroxy5-methylphenyl) benzotriazole,
(2-hydroxy-5-methylphenyl) benzotriazole, (2-hydroxy-3-tert-butyl5-methylphenyl) 5-chlorobenzotriazole and the like.

Cyanoacrylate-based ultraviolet absorbers: ethyl-2-cyano-3,3-diphenylacrylate, methyl 2-carbomethoxy-3 (paramethoxy) acrylate and the like.

Quencher (metal complex salt) UV absorber: nickel (2,2 thiobis (4-t-octyl) phenolate) normal butylamine, nickel dibutyl dithiocarbamate, nickel dibutyl dithiocarbamate, cobalt dicyclohexyl dithiophosphate, etc.

HALS (hindered amine) UV absorber: bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate , 1- [2-
[3- (3,5-Di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionyloxy] -2,2,6,6-tetramethylpyridine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,4
5] Undecane-2,4-dione, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine and the like.

The present invention relates to an electrophotographic photoreceptor in which a photosensitive layer and a protective layer are formed on a conductive substrate and an undercoat layer and an intermediate layer are formed as required, wherein a filler is added to the protective layer. By containing it, the resistance to abrasion is improved and the durability is improved. Furthermore, the electrophotographic photoreceptor of the present invention has excellent durability and stability even for a high-speed electrophotographic process by making the presence form of the filler in the protective layer constant as described above, A photoreceptor with excellent wear resistance.

Further, in the electrophotographic process using the electrophotographic photoreceptor of the present invention, by supplying a lubricating material on the protective layer, filming can be suppressed with good abrasion resistance. Further, in the electrophotographic process including the photoreceptor of the present invention, image formation while maintaining abrasion resistance is performed by repeating toner adhesion on the photoreceptor and toner collection operation in the cleaning unit during non-image formation. It has an effect on suppression.

Examples of the lubricant used herein include fatty acid metal soaps such as zinc stearate, zinc laurate, zinc myristate, calcium stearate, and aluminum stearate, and fluororesins such as polytetrafluoroethylene, polyvinylidene fluoride, and PFA. Fine powders and fine powders of an ethylene resin such as polyethylene and polypropylene can be used. Particularly, zinc stearate and calcium stearate are preferable.

If the amount of the lubricant supplied on the photoreceptor is too large, the amount of output on the transferred output image also increases, which is not preferable because it causes a fixing failure. Further, when the friction coefficient of the photoreceptor surface is reduced to about 0.1 due to excessive supply of the lubricant, the image density is lowered, which is not preferable. On the other hand, when the supply amount of the lubricant is small, filming of the toner component on the photoreceptor occurs, which causes image flow and non-uniformity of halftone, which is not preferable. Assuming that, for example,
When the powdery lubricant is contained in the toner and supplied to the surface of the photoreceptor, the content is preferably 0.1 to 0.2% by weight in the toner.

Next, an image forming method and an image forming apparatus according to the present invention will be described. FIG. 3 is a schematic view showing an image forming method and an image forming apparatus useful for using the electrophotographic photosensitive member of the present invention.

The photosensitive member 6 has a drum shape, but may have a sheet shape or an endless belt shape. A charger 7, a transfer charger, a transfer charger, a separation charger, and a charger 8 before cleaning are arranged around the photoreceptor 6 as necessary, and a corotron, a scorotron, a solid charger (solid state charger), and a charging roller are provided. Other known means are arranged.

The charging member 9 may be in contact with the photoreceptor. However, by providing a suitable gap (about 10 to 200 μm) between the charging member 9 and the charging member 9, the amount of wear of both can be reduced and the charging member 9 can be charged. The toner filming on the member can be suppressed, and it can be used favorably. Particularly, in the photoreceptor of the present invention, good characteristics can be maintained by providing a gap of about 50 μm, which is considered to be because the influence of the surface state of the protective layer can be reduced.

It is effective that the voltage applied to the charging member 9 is obtained by superimposing an AC component on a DC component in order to stabilize charging and suppress uneven charging. However, it has been found that, while the charging is stabilized, the surface layer of the photoreceptor used during the process is more likely to be worn than when only a DC component is applied. Also in this case, the photoreceptor of the present invention can maintain good characteristics without any problem due to the high abrasion resistance. As the transfer means, generally, the above-described charger can be used, but a transfer device using a transfer belt 10 as shown in FIG. 3 is effective.

The light sources such as the image exposure unit 11 and the static elimination lamp 12 include a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, and a light emitting diode (LE).
D), semiconductor lasers (LD), electroluminescence (EL), and other general light-emitting materials can be used. Then, in order to irradiate only light in a desired wavelength range, various filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used.

These light sources are used not only in the steps shown in FIG. 3 but also in steps such as a transfer step using light irradiation, a charge elimination step, a cleaning step, and a pre-exposure step. .

The toner developed on the photosensitive member 6 by the developing unit 13 is transferred to the transfer paper 14, but not all of the toner is transferred. Some toner remains on the photosensitive member 6. The toner is removed from the photoconductor 6 by the fur brush 15 and the cleaning blade 16.
Cleaning may be performed only with a cleaning brush, and a fur brush, a mug brush, or the like is used as the cleaning brush.

When the electrophotographic photosensitive member is positively (negatively) charged and subjected to image exposure, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. If this is developed with a negative (positive) polarity toner (electrostatic detection fine particles), a positive image can be obtained.
By developing with a polar toner, a negative image can be obtained. A known method is applied to the developing means, and a known method is also used for the charge removing means. Reference numeral 17 denotes a registration roller, and reference numeral 18 denotes a separation claw.

The present invention is an image forming method and an image forming apparatus using the electrophotographic photosensitive member according to the present invention for such an image forming means. That is, the present invention relates to an image forming method which performs at least charging, image exposure, development, transfer, fixing and cleaning treatments, wherein the image forming method is characterized by using the laminated electrophotographic photoreceptor, and An image forming apparatus having at least charging, image exposing, developing, transferring, fixing and cleaning means, comprising the above-mentioned laminated electrophotographic photosensitive member.

The image forming means may be fixedly incorporated in a copying machine, a facsimile, or a printer, or may be incorporated in such a device in the form of a process cartridge and made detachable. . here,
The process cartridge is one device (part) that includes a photoconductor and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge removing unit.

Accordingly, the present invention also provides at least
A process cartridge for an image forming apparatus having image exposure, development, transfer, fixing, and cleaning means, the process cartridge for an image forming apparatus comprising the laminated electrophotographic photosensitive member is also provided. is there. FIG. 4 is a schematic diagram illustrating an example of a process cartridge for an image forming apparatus.

Further, in the image forming method according to the present invention, it is possible to suppress filming on the surface of the photoconductor while maintaining abrasion resistance by attaching toner to the photoconductor and recovering toner in the cleaning unit during non-image formation. Further, it is possible to suppress the adhesion and deposition of the product due to charging.
This is considered to be due to a cleaning effect in which various kinds of deposits on the photosensitive member are discharged together with the toner. This toner adhesion and collection operation is performed by adjusting the toner adhesion amount of about halftone to 30%.
Operation time of about second (photoreceptor diameter 30 mm, linear velocity 125 mm
/ S) is effective, and any further adhesion amount and operation time are not preferable in view of an increase in load on the cleaning unit and an increase in toner consumption. In the case where the photoconductor diameter and the linear velocity are different, it may be appropriately adjusted so that the same operating conditions as above are obtained.

When the photosensitive layer is scraped,
The electrical characteristics (e.g., charging performance and light attenuation performance) of the photoconductor change, making it impossible to perform a predetermined image forming process, and making it difficult to maintain the quality of the final output hard copy. In the electrophotographic method, this film abrasion occurs in all portions where the photoconductor and other image forming units come into contact with each other, but the most problematic unit is a cleaning unit (blade) that mechanically removes toner remaining on the photoconductor. Or a brush). Although there is some wear by other units, it does not affect the real life.

The wear generated in the cleaning unit is as follows.
There are two main types. One is the abrasion caused by the shear force generated on the photoconductor and the blade (brush), and the other is the toner is sandwiched between the blade (brush) and the photoconductor,
Rough wear that acts like a grindstone and wears.
On the other hand, by providing a protective layer containing a filler on the photoreceptor and making the form of the filler in the protective layer constant, excellent durability and stability even in a high-speed electrophotographic process can be achieved. It has been found that a photosensitive member having excellent abrasion resistance can be obtained.

By improving the abrasion resistance as described above, it becomes possible to make the photoreceptor thinner. In this thin film region, it is suitable for higher definition of an output image, which is very advantageous as an image forming apparatus.

[0124]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by these Examples. All parts are parts by weight.

Example 1 An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following compositions were applied in this order on an aluminum substrate, dried, and dried under 3.5 μm. A pulling layer, a 0.15 μm charge generation layer, and a 20 μm charge transport layer were laminated. Subsequently, a protective layer coating liquid 1 and a protective layer coating liquid 2 each having the following composition were applied in that order and dried, and the protective layer was almost equal in thickness with each protective layer coating liquid, and a total of 5 μm protective layers were laminated. A photoreceptor was prepared. At this time, the coating of the protective layer was performed by a spray method, and the rest was performed by a dip coating method. In addition, in the preparation of the coating liquids 1 and 2 for the protective layer, the dispersing aid was added at the beginning of the preparation.

[Undercoat layer coating solution] Titanium dioxide powder 400 parts Melamine resin 65 parts Alkyd resin 120 parts 2-butanone 400 parts

[Charge Generating Layer Coating Solution] Bisazo pigment of the following structural formula (Formula 1) 12 parts Polyvinyl butyral 5 parts 2-butanone 200 parts Cyclohexanone 400 parts

Embedded image

[Charge Transport Layer Coating Solution] Polycarbonate 10 parts Charge transport material of the following structural formula (Formula 2) 8 parts Tetrahydrofuran 200 parts

Embedded image

[Protective Layer Coating Solution 1] Polycarbonate 10 parts Charge transporting material of the above structural formula (Formula 2) 7 parts Alumina fine particles 6 parts (AA-03, manufactured by Sumitomo Chemical Co., Ltd., central particle diameter 0.3 μm) Dispersing aid 0.08 parts (BYK-P104 manufactured by BYK Japan) 700 parts of tetrahydrofuran 200 parts of cyclohexanone

[Protective Layer Coating Solution 2] Polycarbonate 10 parts Charge transport material of the above structural formula (Formula 2) 7 parts Alumina fine particles 6 parts (AA-03, manufactured by Sumitomo Chemical Co., Ltd., central particle size 0.3 μm) Dispersing aid 0.06 parts (BYK-P104 manufactured by BYK Japan) 700 parts of tetrahydrofuran 200 parts of cyclohexanone

When the cross section of the protective layer in each layer lamination direction of the photoreceptor thus manufactured was observed by SEM to check the dispersion state of the filler in the protective layer, the particle size distribution peak was 0.2 μm. It was confirmed that the amount of filler having a particle diameter of 0.3 μm or more including secondary particles was larger on the surface layer side than on the substrate side. The area occupancy of the filler in the plane is 3.5%, and the area occupied by the filler having a particle diameter of 0.3 μm or more occupies 18% of the total area occupied by the filler in the plane. there were.

Further, the same photoreceptor was prepared on an aluminum substrate having a diameter of 30 mm, and the durability was evaluated by the electrophotographic process shown in FIG. At this time, the image exposure was 655 nm laser exposure, and the charging
C (2 kHz, 1.8 kVpp) + DC (-750 V)
Was applied. The process speed of this process is 125 mm /
s. The output image was almost good even at the initial stage and after 50,000 continuous sheets, and slight halftone unevenness was observed after 50,000 sheets. The abrasion loss of the photoreceptor after 50,000 sheets of continuous paper passing was 1.8 μm.

Example 2 An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the charge transporting material used in the charge transporting layer and the protective layer in Example 1 was changed to that of the following structural formula (Formula 3). Was prepared.

Embedded image

When the cross section of the protective layer in each layer lamination direction of the photoreceptor thus manufactured was observed by SEM to examine the dispersion state of the filler in the protective layer, the particle size distribution peak was 0.2 μm. It was confirmed that the amount of filler having a particle diameter of 0.3 μm or more including secondary particles was larger on the surface layer side than on the substrate side. The area occupancy of the filler in the plane is 4.7%, and the area occupied by the filler having a particle size of 0.3 μm or more occupies 13% of the total area occupied by the filler in the plane. there were.

Further, when the durability in the electrophotographic process was evaluated in the same manner as in Example 1, the output image was almost good both at the initial stage and after 50,000 continuous paper passes.
Slight halftone unevenness was observed after 10,000 copies. The abrasion loss of the photoreceptor after 50,000 sheets of continuous paper passing was 2.0 μm.

Example 3 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the coating liquid for the charge generation layer and the coating liquid for the protective layer used in Example 1 were changed to the following. In addition, in the preparation of the protective layer coating liquids 3 and 4, the dispersing aid was added at the beginning of the preparation.

[Charge Generating Layer Coating Solution] Titanyl phthalocyanine 7 parts Polyvinyl butyral 5 parts 2-butanone 400 parts

[Protective Layer Coating Solution 3] Polycarbonate 10 parts Charge transport material of the above structural formula (Formula 3) 7 parts Alumina fine particles 6 parts (AA-03 manufactured by Sumitomo Chemical Co., Ltd., central particle diameter 0.3 μm) Dispersing aid 0.08 parts (BYK-P104 manufactured by BYK Japan) 700 parts of tetrahydrofuran 200 parts of cyclohexanone

[Protective Layer Coating Solution 4] Polycarbonate 10 parts Charge transport material of the above structural formula (Formula 3) 7 parts Alumina fine particles 6 parts (AA-03, manufactured by Sumitomo Chemical Co., Ltd., central particle diameter 0.3 μm) Dispersing aid 0.05 parts (BYK-P104 manufactured by BYK Japan) 700 parts of tetrahydrofuran 200 parts of cyclohexanone

When the cross section of the protective layer of the photoreceptor thus produced in the layer stacking direction was observed by SEM to check the dispersion state of the filler in the protective layer, the particle size distribution peak was 0.3 μm. It was confirmed that the amount of filler having a particle diameter of 0.3 μm or more including secondary particles was larger on the surface layer side than on the substrate side. The area occupation ratio of the filler in the plane is 3.9%, and the occupation area of the filler having a particle size of 0.3 μm or more occupies 27% of the total occupation area of the filler in the plane. there were.

Further, when the durability in the electrophotographic process was evaluated in the same manner as in Example 1, the output image was almost good both at the initial stage and after 50,000 sheets of continuous paper passing.
Slight halftone unevenness was observed after 10,000 copies. The image exposure at this time was 780 nm laser exposure. The amount of wear of the photoreceptor after 50,000 sheets of continuous paper passing was 2.3 μm.

Comparative Example 1 An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the coating liquid for the protective layer was changed to one kind of the coating liquid for the protective layer 1 in Example 1 and no dispersing agent was used. did.

The cross section of the protective layer in the lamination direction of each layer of the photoreceptor thus manufactured was observed by SEM to examine the dispersion state of the filler in the protective layer. The particle size distribution of the filler in the plane was random. And the area occupancy of the filler in the plane was 3.7%. The peak of the particle size distribution was 0.3 μm, and the ratio of the area occupied by the filler having a particle size of 0.3 μm or more to the total area occupied by the filler in the plane was 43%.

Further, the durability of the electrophotographic process was evaluated in the same manner as in Example 1. As a result, black streaks due to poor cleaning gradually occurred in the output image after 50,000 continuous paper passes. Further, the abrasion amount of the photoconductor after 50,000 sheets of continuous paper passing was 2.5 μm.

Comparative Example 2 The filler added to the protective layer in Example 2 was alumina fine particles, and AA-0 manufactured by Sumitomo Chemical Co., Ltd. was used.
7. An electrophotographic photoreceptor was prepared in the same manner as in Example 2, except that the center particle diameter was changed to 0.7 μm, and the protective layer coating liquid was changed to one type using the protective layer coating liquid 1.

When the cross section of the protective layer in each layer lamination direction of the photoreceptor thus manufactured was observed by SEM to examine the dispersion state of the filler in the protective layer, the particle size distribution peak was 0.6 μm. The area occupancy of the filler in that plane was 5.4%.

Further, the durability of the electrophotographic process was evaluated in the same manner as in Example 2. As a result, black streaks due to poor cleaning gradually occurred in the output image after 50,000 continuous paper passes. The abrasion loss of the photoreceptor after 50,000 sheets of continuous paper passing was 1.8 μm.

Example 4 In the electrophotographic process of Example 1, 0.1% powdered zinc stearate was added to the toner supplied to the developing section, and the durability was evaluated.
The output image was very good even at the initial stage and after 50,000 continuous sheets, and no halftone unevenness was observed after 50,000 sheets. The abrasion loss of the photoreceptor after 50,000 sheets of continuous paper passing was 1.3 μm.

(Embodiment 5) In the electrophotographic process of Embodiment 4, every 2,000 sheets are passed, a non-image forming operation is performed by exposing to a light portion potential, toner developing by a developing unit, and a photosensitive member by a cleaning unit. Only the operation of collecting the toner on the surface was repeated for 30 seconds, and a paper passing test of 50,000 sheets was performed. The output image was extremely good even after 50,000 sheets of continuous paper passing, and no halftone unevenness was observed even after 50,000 sheets. The abrasion loss of the photoreceptor after 50,000 sheets of continuous paper passing was 2.3 μm.

Further, after 50,000 sheets of continuous paper are passed, 30 ° C. and 90%
When an image was output in a high-temperature, high-humidity environment of RH, no reduction in resolution due to image deletion was observed.

(Example 6) In the electrophotographic process of Example 4, a gap material made of a PET film having a thickness of 50 µm was provided with a width of 10 mm at both ends and non-image portions of the charging roller, and the charging roller was brought close to the photosensitive member. Except for the arrangement, the durability was evaluated in the same manner as in Example 4. The output image was very good even at the initial stage and after 50,000 continuous sheets, and no halftone unevenness was observed after 50,000 sheets. The abrasion loss of the photoreceptor after 50,000 sheets of continuous paper passing was 1.2 μm. At this time, there was almost no attached matter such as a toner component on the surface of the charging roller, and almost the initial state was maintained, and it was confirmed that the durability of the charging roller was effective.

Comparative Example 3 An electrophotographic photosensitive member was produced in the same manner as in Example 4, except that no filler and a dispersing agent were added to the protective layer of the photosensitive member. At this time, the protective layer coating liquid is one type containing no filler and no dispersing aid.

The photoreceptor thus produced was used in Example 4.
The durability was evaluated by the same electrophotographic process as described above. Although the output image was good in the initial stage, filming occurred on the entire surface of the photoreceptor after 50,000 sheets of continuous paper were passed, and unevenness of halftones was observed due to poor cleaning due to poor cleaning. The abrasion loss of the photoreceptor after 50,000 sheets of continuous paper passing was 6.3 μm on average in the axial direction, and the protective layer component was almost worn. After 50,000 sheets of continuous paper, 3
When an image was output in a high-temperature and high-humidity environment of 0 ° C. and 90% RH, image deletion occurred on the entire surface.

[0154]

According to the first aspect of the present invention, the filler contained in the protective layer on the surface of the photoreceptor has a peak at 0.2 to 0.3 μm in the particle size distribution including the secondary particles. And the amount of filler having a particle size of 0.3 μm or more in the surface layer side is larger than that in the substrate side, so that the laminated electrophotographic photosensitive material has excellent durability and abrasion resistance to a high-speed electrophotographic process. Body can be provided.

According to the second and third aspects of the present invention, the effect of the first aspect of the present invention can be further improved by further restricting the form of the filler contained in the protective layer.

According to the fourth, eighth and twelfth aspects of the present invention, there is provided an image forming method, an image forming apparatus and a process cartridge for an image forming apparatus employing an electrophotographic method, wherein the laminated electrophotographic photosensitive member has the protective layer. By using, a long-term image forming operation can be favorably performed.

According to the fifth, sixth, ninth, tenth, thirteenth, and fourteenth aspects of the present invention, since the lubricant is supplied directly to the surface of the photoreceptor or through the toner, the abrasion resistance is improved and the surface of the photoreceptor is improved. The occurrence of filming is prevented as much as possible.

According to the seventh, eleventh, and fifteenth aspects of the present invention, the toner is adhered to the photosensitive member and the toner is collected in the cleaning unit during non-image formation, so that the photosensitive member is maintained in a state where the abrasion resistance is maintained. Filming on the body surface can be suppressed, and the photoreceptor surface is further cleaned.

According to the sixteenth and seventeenth aspects of the present invention, the charging means for the photoconductor is arranged in contact with or close to the photoconductor, and a voltage obtained by superimposing an AC component on a DC component is applied to the charging member. By doing so, the charging is stabilized while the charging member is kept good.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a laminated electrophotographic photosensitive member of the present invention.

FIG. 2 is a schematic sectional view of another laminated electrophotographic photosensitive member of the present invention.

FIG. 3 is a diagram illustrating an image forming apparatus and an image forming apparatus according to the present invention.

FIG. 4 is a schematic view illustrating an example of a process cartridge for an image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductive support 2 Photosensitive layer 3 Charge generation layer 4 Charge transport layer 5 Protective layer 6 Photoreceptor 7 Charger before transfer 8 Charger before cleaning 9 Charging member 10 Transfer belt 11 Image exposure part 12 Static elimination lamp 13 Developing unit 14 Transfer paper 15 Fur brush 16 cleaning blade 17 registration roller 18 separation claw 101 photosensitive drum 102 charging device 103 exposure 104 developing device 105 transfer body 106 transfer device 107 cleaning blade 108 static elimination lamp 109 fixing device

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tatsuya Niimi 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (Reference) 2H003 AA11 AA12 BB11 CC00 CC04 2H005 AA08 EA05 2H034 AA06 AA07 2H068 AA04 AA34 AA35 FA27 FC15

Claims (17)

[Claims] Claims: 1. A charge generating layer on a conductive substrate,
In a laminated electrophotographic photosensitive member having a charge transport layer and a protective layer, the protective layer contains a filler, and the filler has a particle size distribution including secondary particles of 0.2 to 0.3.
A layered electrophotographic photoreceptor having a peak at μm and having a larger amount of filler having a particle size of 0.3 μm or more on the surface layer side than on the conductive substrate side. 2. The layered electrophotographic photosensitive member according to claim 1, wherein the filler content of the protective layer in an arbitrary cross section perpendicular to the conductive substrate is 3 to 5% as an area occupancy in the plane. A laminated electrophotographic photosensitive member, characterized in that: 3. The layered electrophotographic photoreceptor according to claim 2, wherein an area occupied by a filler having a particle size of 0.3 μm or more in an arbitrary cross section in a direction perpendicular to the conductive substrate of the protective layer is in a plane thereof. 10-30% of total filler occupation area
A laminated electrophotographic photosensitive member, characterized in that: 4. An image forming method which performs at least charging, image exposing, developing, transferring, fixing and cleaning processes, wherein the laminated electrophotographic photosensitive member according to claim 1 is used. Image forming method. 5. The image forming method according to claim 4, wherein a lubricant is supplied and applied to the surface of the photoreceptor. 6. The image forming method according to claim 4, wherein the toner supplied to the developing unit contains a powdery lubricant. 7. The image forming method according to claim 4, wherein at the time of non-image formation, a step of adhering toner from the developing unit to the surface of the photoconductor, and collecting the toner on the photoconductor by the cleaning unit. And repeating the process,
An image forming method comprising cleaning the surface of the photoreceptor. 8. An image forming apparatus having at least charging, image exposing, developing, transferring, fixing and cleaning means, comprising the laminated electrophotographic photosensitive member according to claim 1. Description: Image forming apparatus. 9. The image forming apparatus according to claim 8, further comprising: means for supplying and applying a lubricant to the surface of the photoreceptor. 10. The image forming apparatus according to claim 8, wherein the developing means includes a powdery lubricant in the toner supplied to the developing unit. 11. The image forming apparatus according to claim 8, wherein at the time of non-image formation, a step of attaching toner to the surface of the photosensitive member from the developing unit and a step of collecting the toner on the photosensitive member by the cleaning unit. An image forming apparatus comprising: a photoconductor cleaning unit that repeatedly performs a step of performing a cleaning process. 12. A process cartridge for an image forming apparatus having at least charging, image exposure, development, transfer, fixing and cleaning means, comprising the laminated electrophotographic photosensitive member according to claim 1. A process cartridge for an image forming apparatus. 13. The process cartridge for an image forming apparatus according to claim 12, further comprising: means for supplying and applying a lubricant to the surface of the photoreceptor. 14. A process cartridge for an image forming apparatus according to claim 12, wherein the developing means contains a powdery lubricant in the toner supplied to the developing section. cartridge. 15. The process cartridge for an image forming apparatus according to claim 12, wherein, during non-image formation, a step of adhering toner from a developing unit to the surface of the photoreceptor, and a step of cleaning the photoreceptor. A process cartridge for an image forming apparatus, comprising: a photoconductor cleaning unit that repeatedly performs a step of collecting toner. 16. An image forming method, an image forming apparatus or a process cartridge for an image forming apparatus according to claim 4, wherein the charging means for charging the photosensitive member is arranged in contact with or close to the photosensitive member. An image forming method, an image forming apparatus, or a process cartridge for an image forming apparatus. 17. An image forming method, an image forming apparatus, and a process cartridge for an image forming apparatus according to claim 16, wherein a voltage in which an alternating current component is superimposed on a direct current component is applied to the charging member to apply a voltage to the photosensitive member. An image forming method, an image forming apparatus, or a process cartridge for an image forming apparatus, wherein charging is performed.