JP2000242018A - Electrophotographic photoreceptor and preparation of photoreceptor drum - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrophotographic photoreceptor having high printing and scuffing resistances and satisfying electrophotographic characteristics by using a layer formed by applying and curing a composition essentially containing silica particles, an organic compound boding chemically to the silica particles and a photopolymerization initiator as a surface protective layer. SOLUTION: A surface protective layer is formed on an electric charge generating layer by applying and curing a composition essentially containing silica particles, an organic compound boding chemically to the silica particles and a photopolymerization initiator. The organic compound has polymerizable unsaturated groups of formulae I and II and bond to the silica particles by way of a silyloxy group. In the formula I, X is -NH-, -O- or -S-, Y is O or S, and when X is -O-, Y is S.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor technology, and more particularly, to a composition mainly comprising a silica particle, an organic compound chemically bonded to the silica particle, and a photopolymerization initiator. The present invention relates to an electrophotographic photoreceptor and a method for producing a photosensitive drum that have high printing durability and scratch resistance and satisfy electrophotographic characteristics by forming a layer formed by applying and curing an object.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic photosensitive member, there are advantages such as a wide selection of materials and high productivity.
Photoconductors using organic photoconductive materials have been put to practical use.
In these photoconductors, a function-separated stacked photoconductor and a single-layer photoconductor are often used as a configuration of a positively-charged photoconductor using a positively-charged liquid toner or a powder toner by a reversal development method. .

[0003] As a laminated type photoreceptor, a charge transport layer and a charge generation layer are formed on an aluminum (including aluminum alloy) support or on a substrate having an intermediate layer formed on the aluminum support (hereinafter referred to as a conductive substrate). And a hole transport type photoreceptor in which a charge generation layer and an electron transport layer are sequentially formed on the conductive substrate. Such prior art is disclosed in, for example,
-358158 (first prior art), JP-A-10-
No. 63018 (the second prior art).

On the other hand, as a single-layer type photoreceptor, a photoreceptor in which a photosensitive layer containing a charge generating material and a charge transporting material is formed on the conductive substrate has been put to practical use. The photosensitive layer may contain at least one or more of an electron transporting material, an electron donating material, and an electron accepting material.
As such a conventional technique, for example, Japanese Patent Laid-Open No. 10-1
There is one described in JP-A-15941 (third prior art).

[0005]

SUMMARY OF THE INVENTION An electrophotographic process is
In a dark place, the photoconductor is charged by corona discharge or the like, an electrostatic latent image is formed on the surface of the photoconductor by exposure, and the latent image is visualized by toner development. In order to be applied to this process, the electrophotographic photoreceptor is required to have a chargeability in a dark place and a sensitivity of rapidly erasing the charged charge by light irradiation. Further, the surface of the photoreceptor that is used repeatedly is required to have durability against physical deterioration such as deterioration of the composition due to ozone generated by corona charging, and scratches and abrasion in the development, transfer and cleaning steps.

However, in the case of a single-layer type photoreceptor as shown in the third prior art, if the materials used are mixed to form only a single layer, the chargeability, sensitivity, and fatigue of the electrostatic property are reduced. There has been a problem that the phenomenon is reduced to a level lower than a practical level.

[0007] Therefore, in view of the advantage of the electrical characteristics, a laminated type photoreceptor rather than a single layer type is often applied to an electrophotographic process. In such a case, an electron transporting material exhibiting high mobility is required. At present, there is a problem that the sensitivity is low, the residual potential is large, and the practicability is poor. Furthermore, many acceptor compounds used as electron transporting materials are mutagenic substances and are not practical.

On the other hand, the most practical material property that satisfies the above-mentioned electrical characteristics is a laminated hole transport type photoreceptor. However, in the hole transport type photoreceptor, a charge generation layer is provided on the charge transport layer. Since the charge generation layer, which is usually a thin layer of 2 μm or less, is formed as an upper layer, even a slight scratch or the like appears as an image defect. It is necessary to further provide a protective layer on the charge generation layer. Also in the first prior art, a thermosetting coating material is used for the surface protective layer. However, heat treatment at high heat for a long time is required, and the electrophotographic characteristics may vary depending on the type of the organic photoconductive material and the base material. There is a problem that it is difficult to use because of a problem such as lowering.
Furthermore, when a curable resin is used only for the surface protective layer, there is a problem that printing durability and scratch resistance are insufficient in the case of a contact developing system.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a silica particle, an organic compound chemically bonded to the silica particle, and a photopolymerization initiator. Providing a layer formed by applying and curing a composition mainly containing a compound having high printing durability and scratch resistance and satisfying electrophotographic characteristics, and a method for producing a photosensitive drum. It is in.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a positively chargeable electrophotographic photosensitive member used in a reversal development system using a positively chargeable liquid toner or a powdery toner. On the layer, having a surface protective layer formed by applying and curing a composition mainly containing silica particles and an organic compound chemically bonded to the silica particles and a photopolymerization initiator,
The organic compound of the surface protective layer is a polymerizable unsaturated group of the formula (5) and the formula (6) (where X is selected from -NH-, -O- and -S-, and Y is an oxygen atom and a sulfur atom. Selected from atoms, provided that when X is -O-, Y is a sulfur atom), and the silica particles and the organic compound are bonded via a silyloxy group. Electrophotographic photoreceptor.

Embedded image

Embedded image According to a second aspect of the present invention, there is provided the electrophotographic photosensitive member according to the first aspect, wherein the thickness of the surface protective layer is set to about 0.5 to 10 μm. According to a third aspect of the present invention, in the electronic device according to the first aspect, the surface protective layer is photo-cured mainly using ultraviolet light having a wavelength of about 310 nm or less. Exists in photoreceptors. The gist of claim 4 of the present invention is that the photoreceptor of the positive charging type by the reversal development system, a conductive substrate that functions as a support for another layer while simultaneously functioning as an electrode of the photoreceptor, The electron according to claim 1, further comprising a charge transport layer formed on the conductive substrate, and the charge generation layer formed on the charge transport layer. Exists in photoreceptors. The gist of claim 5 of the present invention is that the photoreceptor of the positive charging type by the reversal development method, and a conductive substrate that functions as a support of another layer while simultaneously functioning as an electrode of the photoreceptor, The image forming apparatus according to claim 1, further comprising: an adhesive layer formed on the conductive substrate, a charge transport layer formed on the adhesive layer, and the charge generation layer formed on the charge transport layer. 4. The electrophotographic photosensitive member according to any one of 1 to 3, above. The gist of claim 6 of the present invention is a method of making a positively charged photosensitive drum used in a reversal development method using a positively charged liquid toner or powder toner,
A step of applying a composition mainly containing silica particles and an organic compound chemically bonded to the silica particles and a photopolymerization initiator on the charge generation layer and curing the composition to form a surface protective layer; The organic compound of the protective layer is a polymerizable unsaturated group represented by the formula (7) and the formula (8) (where X is selected from —NH—, —O— and —S—, and Y is selected from an oxygen atom and a sulfur atom. Wherein X is -O- and Y is a sulfur atom), and the silica particles and the organic compound are bonded via a silyloxy group. It is in making drums.

Embedded image

Embedded image According to a seventh aspect of the present invention, there is provided a method of manufacturing a photosensitive drum according to the sixth aspect, further comprising the step of setting the thickness of the surface protective layer to about 0.5 to 10 μm. The gist of claim 8 of the present invention is to provide a photosensitive drum according to claim 6, further comprising a step of photo-curing the surface protective layer mainly using ultraviolet light having a wavelength of about 310 nm or less. In the method of creation. The gist of the ninth aspect of the present invention resides in a step of forming the positively charged photoconductor by a reversal development method, and a conductive layer that functions as an electrode of the photoconductor and functions as a support for another layer. 7. The method according to claim 6, further comprising: forming a conductive substrate; forming a charge transport layer on the conductive substrate; and forming the charge generation layer on the charge transport layer. 8. The method for producing a photosensitive drum according to any one of Items 8 to 8. Further, the gist of the present invention is a step of forming the positively charged photoreceptor by the reversal development method and a step of forming a conductive substrate that functions as a support for another layer while simultaneously functioning as an electrode of the photoreceptor. Forming an adhesive layer on the conductive substrate, forming a charge transport layer on the adhesive layer, and forming the charge generation layer on the charge transport layer. The present invention resides in a method for producing a photosensitive drum according to any one of claims 6 to 8.

[0011]

(First Embodiment) FIG. 1 shows a laminated electrophotographic photosensitive member according to a first embodiment of the present invention. FIG.
Referring to FIG. 1, the electrophotographic photoreceptor of the first embodiment is a positively-charged photoreceptor based on a reversal developing method,
A charge transport layer 2, a charge generation layer 3, and a surface protection layer 4 are provided thereon, and the charge transport layer 2, the charge generation layer 3, and the surface protection layer 4 are sequentially formed on the conductive substrate 1.

The conductive substrate 1 serves as an electrode of the photoreceptor and serves as a support for another layer, and may be in any form of a cylinder, a plate, or a belt. As the material,
A conductive material such as a deposited film of aluminum or gold, or a coated film of a conductive polymer may be applied to a metal such as aluminum, stainless steel, nickel, or an insulating substrate such as glass or plastic.

Charge transport layer 2 formed on conductive substrate 1
Is formed by applying or dissolving or dispersing a charge transport material and a binder resin for dispersing and fixing the same in a solvent. Additives such as antioxidants, surface lubricants, and ultraviolet absorbers can be used in the charge transport layer coating.

The charge transporting materials include poly-N-vinylcarbazole and derivatives thereof, pyrene-oxadiazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, pyrazoline derivatives, hydrazone derivatives, butadiene derivatives. And other known materials. The charge transport materials can be used alone or in combination of two or more.

As the binder resin for dispersing and fixing the charge transport material, polyvinyl chloride, polyvinyl acetate,
Polyvinyl butyral, polyvinyl formal, polyester, polyurethane, polycarbonate, acrylic resin, phenol resin, silicone resin, epoxy resin and the like are used. These resins can be used alone or in combination of two or more.

As the solvent, toluene, xylene, monochlorobenzene, ethyl acetate, dichloromethane, tetrahydrofuran, cyclohexane methyl ethyl ketone and the like are used. These solvents can be used alone or as a mixture. The thickness of the charge transport layer 2 is appropriately about 5 to 40 μm, preferably about 10 to 30 μm. As a method for coating the charge transport layer 2, a known method such as a spin coater, an applicator, a spray coater, a bar coder, a dip coater, or a doctor blade is used.

The charge generation layer 3 formed on the charge transport layer 2 is formed by dissolving or dispersing a charge generation material and a binder resin for dispersing and fixing the same in a solvent. It is formed by applying a paint.
The charge generation material is preferably a material having a high charge generation efficiency with respect to the light source and a high charge injection efficiency with respect to the charge transport layer 2, and includes phthalocyanine compounds such as metal-free phthalocyanine, copper phthalocyanine, titanyl phthalocyanine, and various azo compounds. And quinone and the like. Examples of the binder resin used at this time include polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyvinyl formal, polyester, polyurethane, polycarbonate, acrylic resin, phenol resin, silicone resin, epoxy resin and the like. These resins are 1
Species can be used, or two or more can be used in combination.
As the solvent, toluene, xylene, monochlorobenzene, ethyl acetate, dichloromethane, tetrahydrofuran, cyclohexane, methyl ethyl ketone, or the like is used. These solvents can be used alone or as a mixture.
The thickness of the charge generation layer 3 is about 0.05 to 5 μm, preferably about 0.1 to 2 μm. A known method such as a spin coater, an applicator, a spray coater, a bar coater, a dip coater, and a doctor blade is used as a method for applying the charge generation layer 3.

The surface protective layer 4 formed on the charge generating layer 3 is coated with a composition mainly containing silica particles, an organic compound chemically bonded to the silica particles and a photopolymerization initiator.
The organic compound comprises a layer formed by curing, and the organic compound has a polymerizable unsaturated group, a group represented by the following formula (9), and a group represented by the following formula (10); The silica particles and the organic compound are bonded via a silyloxy group. At this time, the surface protection layer 4
May contain an electron transporting material having a weight concentration of about 0.01% or more and about 10% or less. Further, it is desirable that the film thickness of the surface protective layer 4 is about 0.5 μm or more and about 10 μm or less.

[0019]

Embedded image

[0020]

Embedded image Here, in the formulas (9) and (10), X represents —NH—, —O
-And -S-, and Y is selected from an oxygen atom and a sulfur atom. However, when X is -O-, Y is a sulfur atom.

As a solvent of the surface protective layer paint used for forming the surface protective layer 4, a composition mainly containing silica particles, an organic compound chemically bonded thereto and a photopolymerization initiator is used. A solvent that can be dissolved and does not affect the charge generation layer 3 can be used as appropriate. Examples of the solvent include alcohols such as isopropyl alcohol, methyl alcohol, and ethyl alcohol, methyl ethyl ketone, toluene, water, and the like.

When an electron transporting material is added to the surface protective layer 4, the coating of the surface protective layer 4 can be adjusted by the following method. The electron transport material is dissolved in a first organic solvent in which the electron transport material is soluble in an amount of about 10% or more and is dilutable with respect to the organic solvent contained in the photocurable coating stock solution, thereby preparing an electron transport material solution. I do. Subsequently, the organic solvent in which the electron transporting material is dissolved is added to the second organic solvent which is difficult to dissolve in the electron transporting material but is dilutable with respect to the organic solvent contained in the photocurable paint. The transport material solution is dispersed and diluted, and further diluted and dispersed in a photocurable coating stock solution to prepare a surface protective coating. Examples of the first organic solvent include dichloromethane and methyl ethyl ketone, and examples of the second organic solvent include alcohols such as isopropyl alcohol, methyl alcohol, and ethyl alcohol, and water.

As a method of applying the surface protective layer paint on the charge generation layer 3, a known method such as a spin coater, an applicator, a spray coater, a bar coder, a dip coater, a doctor blade or the like is used.

After the application, the solvent of the surface protective layer paint is dried using a high-temperature drier, a reduced-pressure drier or the like. Drying conditions are above room temperature, below the temperature at which the coated photoreceptor does not denature,
Generally, it is about 60 ° C. or more and about 150 ° C. or less.

After drying the solvent, the coating film is irradiated with ultraviolet light,
The surface protective layer coating is cured by reaction. Although the ultraviolet wavelength varies depending on the photopolymerization initiator, a low-pressure mercury lamp, a high-pressure mercury lamp, a xenon lamp, or the like can be used as a light source. In the present invention, a wavelength of about 310 nm or less is mainly used as a curing ultraviolet wavelength. This is because, in order to prevent isomerization and decomposition of the organic material due to irradiation of the ultraviolet light, ultraviolet light having a high absorption coefficient of the organic material is used, and the ultraviolet light is absorbed as much as possible near the surface of the photoreceptor. As a result, it is possible to prevent phenomena such as deterioration and performance degradation of the photoconductor due to isomerization and decomposition of the organic material and an optical memory effect, and to produce an electrophotographic photoconductor having excellent electrophotographic characteristics and excellent durability.

As described above, according to the first embodiment, the surface protective layer 4 is coated with a composition mainly containing silica particles, an organic compound chemically bonded to the silica particles, and a photopolymerization initiator. By adding a charge transporting material to the cured layer or the surface protective layer 4, it is possible to provide an electrophotographic photosensitive member having high printing durability and scratch resistance and satisfying electrophotographic characteristics. it can.

(Second Embodiment) FIG. 2 shows a laminated electrophotographic photosensitive member according to a second embodiment of the present invention. Note that the same parts as those already described in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. Referring to FIG. 2, the electrophotographic photoreceptor according to the second embodiment is a positively-charged photoreceptor based on a reversal development method, in which an intermediate layer (insulating layer) 5, a charge transport layer 2, a charge Generation layer 3,
An intermediate layer (insulating layer) 5, a charge transport layer 2, a charge generation layer 3, and a surface protection layer 4 are provided on the conductive substrate 1.
Are sequentially formed.

As described above, according to the second embodiment, the surface protective layer 4 is coated with a composition mainly containing silica particles, an organic compound chemically bonded to the silica particles, and a photopolymerization initiator. By adding a charge transporting material to the cured layer or the surface protective layer 4, it is possible to provide an electrophotographic photosensitive member having high printing durability and scratch resistance and satisfying electrophotographic characteristics. it can.

It should be noted that the present invention is not limited to the above embodiments, and each embodiment can be appropriately modified within the scope of the technical idea of the present invention. Further, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiment,
The number, position, shape, and the like suitable for carrying out the present invention can be obtained.

[0030]

(Example 1) A charge transporting material represented by the following formula (1)
The tristyryltriphenylamine compound represented by 1) and a polycarbonate as a binder resin (for example, Z
-400, manufactured by Mitsubishi Gas Chemical Co., Ltd.) is dissolved in tetrahydrofuran (hereinafter referred to as THF) solvent, and the plate-type alumite substrate 1 is immersed in a paint for the charge transport layer 2 to form a coating film (for example, about 20 μm). Was formed to form the charge transport layer 2.

[0031]

Embedded image

On the charge transport layer 2, titanyl phthalocyanine (hereinafter referred to as TiOPc) as a charge generating material and polyvinyl butyral resin (for example, B
X-1 (manufactured by Sekisui Chemical Co., Ltd.) was dispersed in a THF solvent, and a coating material (approximately 0.25 μm) was formed by applying a paint for the charge generation layer 3 prepared by dipping.

Subsequently, a stock solution (for example, Desolite Z750) containing silica particles and a composition mainly containing an organic compound chemically bonded thereto and a photopolymerization initiator is used.
Isopropyl alcohol was added and diluted with stirring to prepare a surface protective layer paint. The paint for the surface protective layer was applied on the charge generating layer 3 by a dipping method. After drying at about 90 ° C for about 20 minutes, use a low-pressure mercury lamp to irradiate
Irradiated for about 1 minute to form a surface protective layer 4 having a thickness of about 1 μm, thereby producing a laminated electrophotographic photosensitive member.

Example 2 The following formula (1) was used for the charge transport material.
A laminated electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the butadiene derivative shown in 2) was used.

[0035]

Embedded image

Example 3 The following formula (1) was used for the charge transport material.
A laminated electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the hydrazone derivative shown in 3) was used.

[0037]

Embedded image

Example 4 The following formula (1) was used for the charge transport material.
A laminated electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the stilbene derivative shown in 4) was used.

[0039]

Embedded image

Example 5 A laminated electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that τ-type metal-free phthalocyanine (hereinafter referred to as τ-H ₂ Pc) was used as the charge generating material. .

(Embodiment 6) τ-H ₂ Pc
A laminated electrophotographic photoreceptor was prepared in the same manner as in Example 2 except for using.

(Embodiment 7) τ-H ₂ Pc
A laminated electrophotographic photoreceptor was prepared in the same manner as in Example 3 except for using.

(Embodiment 8) τ-H ₂ Pc
A laminated electrophotographic photoreceptor was prepared in the same manner as in Example 4 except for using.

(Comparative Example 1) (Photoreceptor without Surface Protective Layer 4) A laminated electrophotographic photoreceptor was prepared in the same manner as in Example 3 except that the surface protective layer 4 was not provided.

Comparative Example 2 Photosensitive Member without Surface Protective Layer 4 A laminated electrophotographic photosensitive member was prepared in the same manner as in Example 8, except that the surface protective layer 4 was not provided.

An electrostatic charging test apparatus (for example, EPA-8) for measuring the surface potential behavior of these plate-type electrophotographic photosensitive members by repeating a charging-exposure-discharge process.
200, manufactured by Kawaguchi Electric Works), the measurement conditions were room temperature and normal humidity, the corona charging voltage was about 8 kV, and the white exposure was 5.0.
The evaluation of electrophotographic characteristics was performed with Lux approximately. Furthermore,
After immersing the photoreceptors prepared in Examples and Comparative Examples in an aliphatic hydrocarbon (dodecane) for one week, the photoreceptor surface was observed. Table 1 shows the results of these evaluations.

[0047]

[Table 1]

Example 9 A coating film (30) was formed on a disc-shaped alumite substrate by using the same charge-transporting layer paint as in the first example.
μm) to form the charge transport layer 2. Then the first
A surface protection layer 4 is formed on the charge transport layer 2 in the same manner as in the embodiment.
Was formed to prepare a disk-shaped substrate for abrasion test.

(Comparative Example 3) (Abrasion Test Substrate Without Forming Surface Protective Layer 4) A disk-shaped wear test substrate was prepared in the same manner as in the ninth example except that the surface protective layer 4 was not formed. The amount of film abrasion of these disc-shaped abrasion test substrates was measured using a tapered abrasion tester (manufactured by Toyo Seiki Co., Ltd., wear wheel MS-10, additional load 500 g, 1000 rotations). Table 2 shows the evaluation results.

[0050]

[Table 2]

[0051]

According to the present invention, the surface protective layer is coated with a composition mainly containing silica particles, an organic compound chemically bonded to the silica particles, and a photopolymerization initiator. By adding a charge transporting material to the layer formed by curing or the protective layer, it is possible to provide an electrophotographic photosensitive member having high printing durability and scratch resistance and satisfying electrophotographic characteristics.

[Brief description of the drawings]

FIG. 1 is a laminated electrophotographic photosensitive member according to a first embodiment of the present invention.

FIG. 2 shows a laminated electrophotographic photosensitive member according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Conductive substrate 2 ... Charge transport layer 3 ... Charge generation layer 4 ... Surface protective layer 5 ... Intermediate layer

[Procedure amendment]

[Submission date] January 31, 2000 (200.1.3
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

Patent application title: Electrophotographic photoreceptor and photosensitive drum making method

[Claims]

Embedded image

Embedded image

Embedded image

Embedded image

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor technology, and more particularly, to a composition mainly comprising a silica particle, an organic compound chemically bonded to the silica particle, and a photopolymerization initiator. The present invention relates to an electrophotographic photoreceptor and a method for producing a photosensitive drum that have high printing durability and scratch resistance and satisfy electrophotographic characteristics by forming a layer formed by applying and curing an object.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic photosensitive member, there are advantages such as a wide selection of materials and high productivity.
Photoconductors using organic photoconductive materials have been put to practical use.
In these photoconductors, a function-separated stacked photoconductor and a single-layer photoconductor are often used as a configuration of a positively-charged photoconductor using a positively-charged liquid toner or a powder toner by a reversal development method. .

[0003] As a laminated type photoreceptor, a charge transport layer and a charge generation layer are formed on an aluminum (including aluminum alloy) support or on a substrate having an intermediate layer formed on the aluminum support (hereinafter referred to as a conductive substrate). And a hole transport type photoreceptor in which a charge generation layer and an electron transport layer are sequentially formed on the conductive substrate. Such prior art is disclosed in, for example,
-358158 (first prior art), JP-A-10-
No. 63018 (the second prior art).

On the other hand, as a single-layer type photoreceptor, a photoreceptor in which a photosensitive layer containing a charge generating material and a charge transporting material is formed on the conductive substrate has been put to practical use. The photosensitive layer may contain at least one or more of an electron transporting material, an electron donating material, and an electron accepting material.
As such a conventional technique, for example, Japanese Patent Laid-Open No. 10-1
There is one described in JP-A-15941 (third prior art).

[0005]

SUMMARY OF THE INVENTION An electrophotographic process is
In a dark place, the photoconductor is charged by corona discharge or the like, an electrostatic latent image is formed on the surface of the photoconductor by exposure, and the latent image is visualized by toner development. In order to be applied to this process, the electrophotographic photoreceptor is required to have a chargeability in a dark place and a sensitivity of rapidly erasing the charged charge by light irradiation. Further, the surface of the photoreceptor that is used repeatedly is required to have durability against physical deterioration such as deterioration of the composition due to ozone generated by corona charging, and scratches and abrasion in the development, transfer and cleaning steps.

However, in the case of a single-layer type photoreceptor as shown in the third prior art, if the materials used are mixed to form only a single layer, the chargeability, sensitivity, and fatigue of the electrostatic property are reduced. There has been a problem that the phenomenon is reduced to a level lower than a practical level.

[0007] Therefore, in view of the advantage of the electrical characteristics, a laminated type photoreceptor rather than a single layer type is often applied to an electrophotographic process. In such a case, an electron transporting material exhibiting high mobility is required. At present, there is a problem that the sensitivity is low, the residual potential is large, and the practicability is poor. Furthermore, many acceptor compounds used as electron transporting materials are mutagenic substances and are not practical.

On the other hand, the most practical material property that satisfies the above-mentioned electrical characteristics is a laminated hole transport type photoreceptor. However, in the hole transport type photoreceptor, a charge generation layer is provided on the charge transport layer. Since the charge generation layer, which is usually a thin layer of 2 μm or less, is formed as an upper layer, even a slight scratch or the like appears as an image defect. It is necessary to further provide a protective layer on the charge generation layer. Also in the first prior art, a thermosetting coating material is used for the surface protective layer. However, heat treatment at high heat for a long time is required, and the electrophotographic characteristics may vary depending on the type of the organic photoconductive material and the base material. There is a problem that it is difficult to use because of a problem such as lowering.
Furthermore, when a curable resin is used only for the surface protective layer, there is a problem that printing durability and scratch resistance are insufficient in the case of a contact developing system.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a silica particle, an organic compound chemically bonded to the silica particle, and a photopolymerization initiator. Providing a layer formed by applying and curing a composition mainly containing a compound having high printing durability and scratch resistance and satisfying electrophotographic characteristics, and a method for producing a photosensitive drum. It is in.

[0010]

An object of the present invention is to provide a positively chargeable electrophotographic photoreceptor for use in a reversal development system using a positively chargeable liquid toner or a powdery toner,
On the charge generation layer, a surface protective layer formed by applying and curing a composition mainly containing silica particles, an organic compound chemically bonded to the silica particles, and a photopolymerization initiator, the surface protective layer Is a polymerizable unsaturated group of the formula (5) and the formula (6) (where X is -NH-, -O- and -S-
Y is selected from an oxygen atom and a sulfur atom, provided that when X is -O-, Y is a sulfur atom), and the silica particles and the organic compound have a silyloxy group. An electrophotographic photoreceptor characterized in that the photoreceptor is bonded to the electrophotographic photoreceptor.

Embedded image

Embedded image According to a second aspect of the present invention, there is provided the electrophotographic photosensitive member according to the first aspect, wherein the thickness of the surface protective layer is set to 0.5 to 10 μm. Also,
The gist of the invention according to claim 3 is that the surface protective layer is formed of 3
The electrophotographic photoreceptor according to claim 1, wherein the photoreceptor is photocured using ultraviolet light having a wavelength of 10 nm or less. Further, the gist of the invention according to claim 4 is that the photosensitive member of the positive charging type by the reversal developing method, and a conductive substrate that functions as a support of another layer while simultaneously functioning as an electrode of the photosensitive member, The electron according to claim 1, further comprising a charge transport layer formed on the conductive substrate, and the charge generation layer formed on the charge transport layer. Exists in photoreceptors. Further, the gist of the invention according to claim 5 is that the photosensitive member of the positive charging type by the reversal development method, and a conductive substrate that functions as a support of another layer while simultaneously functioning as an electrode of the photosensitive member, The image forming apparatus according to claim 1, further comprising: an adhesive layer formed on the conductive substrate, a charge transport layer formed on the adhesive layer, and the charge generation layer formed on the charge transport layer. 4. The electrophotographic photosensitive member according to any one of 1 to 3, above.
The gist of the invention according to claim 6 is a method for producing a positively charged photosensitive drum used in a reversal development system using a positively charged liquid toner or powder toner, wherein silica particles and A step of applying and curing a composition mainly containing an organic compound chemically bound and a photopolymerization initiator to form a surface protective layer, wherein the organic compound of the surface protective layer is not polymerizable. Saturated group formula (7) and formula (8)
(Wherein X is selected from —NH—, —O— and —S—, and Y is selected from oxygen and sulfur atoms, provided that when X is —O—, Y is a sulfur atom). Wherein the silica particles and the organic compound are bonded via a silyloxy group.

Embedded image

Embedded image The gist of the present invention resides in a method of manufacturing a photosensitive drum according to claim 6, further comprising the step of setting the thickness of the surface protective layer to 0.5 to 10 μm. The gist of the invention according to claim 8 is to provide a method for producing a photosensitive drum according to claim 6, further comprising a step of photo-curing the surface protective layer using ultraviolet light having a wavelength of 310 nm or less. Exist. The gist of the invention described in claim 9 is a step of forming the positively charged type photoconductor by a reversal development method, and a conductive layer functioning as an electrode of the photoconductor and functioning as a support of another layer. 7. The method according to claim 6, further comprising: forming a conductive substrate; forming a charge transport layer on the conductive substrate; and forming the charge generation layer on the charge transport layer. 8. The method for producing a photosensitive drum according to any one of Items 8 to 8. The gist of the invention according to claim 10 is a step of forming the positively charged photoconductor by a reversal development method, and a conductive layer that functions as an electrode of the photoconductor and simultaneously functions as a support for another layer. Forming a conductive substrate, forming an adhesive layer on the conductive substrate, forming a charge transport layer on the adhesive layer, and forming the charge generation layer on the charge transport layer 7. The method according to claim 6, further comprising:
9. The method according to any one of claims 1 to 8, wherein

[0011]

(First Embodiment) FIG. 1 shows a laminated electrophotographic photosensitive member according to a first embodiment of the present invention. FIG.
Referring to FIG. 1, the electrophotographic photoreceptor of the first embodiment is a positively-charged photoreceptor based on a reversal developing method,
A charge transport layer 2, a charge generation layer 3, and a surface protection layer 4 are provided thereon, and the charge transport layer 2, the charge generation layer 3, and the surface protection layer 4 are sequentially formed on the conductive substrate 1.

The conductive substrate 1 serves as an electrode of the photoreceptor and serves as a support for another layer, and may be in any form of a cylinder, a plate, or a belt. As the material,
A conductive material such as a deposited film of aluminum or gold, or a coated film of a conductive polymer may be applied to a metal such as aluminum, stainless steel, nickel, or an insulating substrate such as glass or plastic.

Charge transport layer 2 formed on conductive substrate 1
Is formed by applying or dissolving or dispersing a charge transport material and a binder resin for dispersing and fixing the same in a solvent. Additives such as antioxidants, surface lubricants, and ultraviolet absorbers can be used in the charge transport layer coating.

The charge transporting materials include poly-N-vinylcarbazole and derivatives thereof, pyrene-oxadiazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, pyrazoline derivatives, hydrazone derivatives, butadiene derivatives. And other known materials. The charge transport materials can be used alone or in combination of two or more.

As the binder resin for dispersing and fixing the charge transport material, polyvinyl chloride, polyvinyl acetate,
Polyvinyl butyral, polyvinyl formal, polyester, polyurethane, polycarbonate, acrylic resin, phenol resin, silicone resin, epoxy resin and the like are used. These resins can be used alone or in combination of two or more.

As the solvent, toluene, xylene, monochlorobenzene, ethyl acetate, dichloromethane, tetrahydrofuran, cyclohexane methyl ethyl ketone and the like are used. These solvents can be used alone or as a mixture. The thickness of the charge transport layer 2 is appropriately about 5 to 40 μm, preferably about 10 to 30 μm. As a method for coating the charge transport layer 2, a known method such as a spin coater, an applicator, a spray coater, a bar coder, a dip coater, or a doctor blade is used.

The charge generation layer 3 formed on the charge transport layer 2 is formed by dissolving or dispersing a charge generation material and a binder resin for dispersing and fixing the same in a solvent. It is formed by applying a paint.
The charge generation material is preferably a material having a high charge generation efficiency with respect to the light source and a high charge injection efficiency with respect to the charge transport layer 2, and includes phthalocyanine compounds such as metal-free phthalocyanine, copper phthalocyanine, titanyl phthalocyanine, and various azo compounds. And quinone and the like. Examples of the binder resin used at this time include polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyvinyl formal, polyester, polyurethane, polycarbonate, acrylic resin, phenol resin, silicone resin, epoxy resin and the like. These resins are 1
Species can be used, or two or more can be used in combination.
As the solvent, toluene, xylene, monochlorobenzene, ethyl acetate, dichloromethane, tetrahydrofuran, cyclohexane, methyl ethyl ketone, or the like is used. These solvents can be used alone or as a mixture.
The thickness of the charge generation layer 3 is about 0.05 to 5 μm, preferably about 0.1 to 2 μm. A known method such as a spin coater, an applicator, a spray coater, a bar coater, a dip coater, and a doctor blade is used as a method for applying the charge generation layer 3.

The surface protective layer 4 formed on the charge generating layer 3 is coated with a composition mainly containing silica particles, an organic compound chemically bonded to the silica particles and a photopolymerization initiator.
The organic compound comprises a layer formed by curing, and the organic compound has a polymerizable unsaturated group, a group represented by the following formula (9), and a group represented by the following formula (10); The silica particles and the organic compound are bonded via a silyloxy group.

[0019]

Embedded image

[0020]

Embedded image

Examples of the polymerizable unsaturated group contained in the organic compound include acryloxy, methacryloxy, vinyl, propenyl, butadienyl, styryl, ethynyl, cinnamoyl, maleate, and acrylamide groups. And the like. Among these, an acryloxy group can be mentioned as a particularly preferred one. Examples of the organic compound include a compound represented by the following formula (11).

[0022]

Embedded image X ¹ is an alkoxyl group, a carboxylate group, a halogen atom, an amino group, an oxime group or a hydrogen atom; R ² is a hydrogen atom or a C _{1 to} C ₈ monovalent organic group;
For example, a non-hydrolyzable organic group composed of an alkyl group, an aryl group, an aralkyl group and carbon, oxygen and hydrogen atoms.

[0023] As alkoxy group representing the X ¹ is, for example, methoxy, ethoxy, isopropoxy, butoxy, phenoxy, may be mentioned octyl group, a halogen atom iodine, chlorine, bromine, and the like fluorine Examples of the amino group include monoalkylamino groups such as amino and methylamino, and dialkylamino groups such as dimethylamino and diethylamino. Examples of the oxime group include methylene oxime and dimethylmethylene oxime. Also, m is 1,
2 or 3. Among these, an alkoxyl group is preferred.

[0024] As the alkyl group represented by R ² above, for example, methyl, can be mentioned ethyl, propyl, butyl, octyl, etc. Examples of the aryl group for example, include phenyl, tolyl, xylyl, and p- methoxyphenyl, etc. Examples of the aralkyl group include benzyl and phenylethyl. Examples of the non-hydrolyzable organic group composed of carbon, oxygen and hydrogen atoms include 2-methoxyethyl and 2-methoxyethyl. -Ethoxyethyl, 2-butoxyethyl and the like.

Preferred examples of the hydrolyzable silyl group constituted by the combination of X ¹ , R ² and m include trimethoxysilyl, triethoxysilyl, triisopropoxysilyl, methyldimethoxysilyl and dimethyldimethoxy. Examples thereof include a silyl group.

The above R ³ is selected from divalent organic groups having a C _{1 to} C ₁₂ aliphatic or aromatic structure, and may have a linear, branched or cyclic structure. Such structural units include, for example, methylene,
Ethylene, propylene, methylethylene, butylene, methylpropylene, cyclohexylene, phenylene, 2-
Examples thereof include methylphenylene, 3-methylphenylene, octamethylene, biphenylene, dodecamethylene and the like. Preferred examples among these are methylene, propylene, cyclohexylene, phenylene and the like.

R ⁴ is a divalent organic group having an aliphatic or aromatic structure, and may have a linear, branched or cyclic structure as its structure. As such a structural unit, for example, methylene, ethylene, propylene,
Divalent organic groups having a chain structure skeleton such as tetramethylene, hexamethylene, 2,2,4-trimethylhexamethylene, 1- (methylcarboxyl) -pentamethylene, isophorone, cyclohexylmethane, methylenebis (4-cyclohexane ), Divalent organic groups having an alicyclic structure skeleton such as hydrogenated genylmethane, hydrogenated xylene, hydrogenated toluene, and aromatic ring structures such as benzene, toluene, xylene, paraphenylene, diphenylmethane, diphenylpropane, and naphthalene. It can be selected from divalent organic groups having a skeleton.

X is selected from -NH-, -O- and -S-, preferably -S-, and Y is an oxygen atom or a sulfur atom, preferably an oxygen atom.
However, when X is -O-, Y is a sulfur atom.

X ² is a divalent organic group, and more specifically, a divalent organic group derived from a compound having two or more active hydrogen atoms in the molecule capable of undergoing an addition reaction with an isocyanate group or a thioisocyanate group. And, for example,
Polyalkylene glycols, polyalkylene thioglycols, polyesters, polyamides, polycarbonates, polyalkylene diamines, polyalkylene dicarboxylic acids, polyalkylene diols, and polyalkylene dimercaptans form HX-groups (where X
Is the same as described above) can be exemplified as a divalent organic group derived by removing two.

The above p is 0 or a number of 1 or more, preferably 0 or a number of 1 to 10. When P exceeds 10, the viscosity of the polymerizable unsaturated group-modified hydrolyzable silane tends to be high, so that it becomes easy to handle.

R ⁵ is an n + 1-valent organic group, and is selected from, for example, a linear, branched or cyclic saturated hydrocarbon group, unsaturated hydrocarbon group, and alicyclic organic group. Also, n
Is selected from positive integers of 1 to 20, preferably 1 to 1
0, more preferably 3 to 5.

Y ¹ represents a monovalent organic group having a polymerizable unsaturated group which undergoes an intermolecular cross-linking reaction in the presence of an active radical species. Examples of such are, for example, acryloxy, methacryloxy, vinyl, propenyl,
Examples thereof include a butadienyl group, a styryl group, an ethynyl group, a cinnamoyl group, a maleate group, and an acrylamide group. Among these, an acryloxy group can be mentioned as a preferable one.

The organic compound having the above polymerizable unsaturated group and the group represented by the following formula (12) and the group represented by the following formula (13) is mixed with silica particles, hydrolyzed, The surface protective layer 4 can be formed by chemically bonding the particles and applying and curing a material containing the obtained composition.

[0034]

Embedded image

[0035]

Embedded image Here, in the formulas (12) and (13), X is -NH-,-
It is selected from O- and -S-, and Y is selected from an oxygen atom and a sulfur atom. However, when X is -O-, Y is a sulfur atom.

At this time, the surface protective layer 4 may contain an electron transport material having a weight concentration of about 0.01% to about 10%. Further, the thickness of the surface protective layer 4 is desirably 0.5 μm or more and 10 μm or less.

As a solvent for the surface protective layer paint used for forming the surface protective layer 4, a composition mainly containing silica particles, an organic compound chemically bonded thereto and a photopolymerization initiator is used. A solvent that can be dissolved and does not affect the charge generation layer 3 can be used as appropriate. Examples of the solvent include alcohols such as isopropyl alcohol, methyl alcohol, and ethyl alcohol, methyl ethyl ketone, toluene, water, and the like.

When an electron transporting material is added to the surface protective layer 4, the paint for the surface protective layer 4 can be adjusted by the following method. The electron transport material is dissolved in a first organic solvent in which the electron transport material is soluble in an amount of about 10% or more and is dilutable with respect to the organic solvent contained in the photocurable coating stock solution, thereby preparing an electron transport material solution. I do. Subsequently, the organic solvent in which the electron transporting material is dissolved is added to the second organic solvent which is difficult to dissolve in the electron transporting material but is dilutable with respect to the organic solvent contained in the photocurable paint. The transport material solution is dispersed and diluted, and further diluted and dispersed in a photocurable coating stock solution to prepare a surface protective coating. Examples of the first organic solvent include dichloromethane and methyl ethyl ketone, and examples of the second organic solvent include alcohols such as isopropyl alcohol, methyl alcohol, and ethyl alcohol, and water.

As a method of applying the surface protective layer coating material on the charge generating layer 3, a known method such as a spin coater, an applicator, a spray coater, a bar coder, a dip coater, a doctor blade or the like is used.

After the application, the solvent of the surface protective layer paint is dried using a high-temperature drier, a reduced-pressure drier or the like. Drying conditions are above room temperature, below the temperature at which the coated photoreceptor does not denature,
Generally, it is about 60 ° C. or more and about 150 ° C. or less.

After drying the solvent, the coating film is irradiated with ultraviolet light,
The surface protective layer coating is cured by reaction. Although the ultraviolet wavelength varies depending on the photopolymerization initiator, a low-pressure mercury lamp, a high-pressure mercury lamp, a xenon lamp, or the like can be used as a light source. In the present invention, a wavelength of 310 nm or less is used as a curing ultraviolet wavelength. This is because, in order to prevent isomerization and decomposition of the organic material due to irradiation of the ultraviolet light, ultraviolet light having a high absorption coefficient of the organic material is used, and the ultraviolet light is absorbed as much as possible near the surface of the photoreceptor. As a result, it is possible to prevent phenomena such as deterioration and performance degradation of the photoconductor due to isomerization and decomposition of the organic material and an optical memory effect, and to produce an electrophotographic photoconductor having excellent electrophotographic characteristics and excellent durability.

As described above, according to the first embodiment, the surface protective layer 4 is coated with a composition mainly containing silica particles, an organic compound chemically bonded to the silica particles, and a photopolymerization initiator. By adding a charge transporting material to the cured layer or the surface protective layer 4, it is possible to provide an electrophotographic photosensitive member having high printing durability and scratch resistance and satisfying electrophotographic characteristics. it can.

(Second Embodiment) FIG. 2 shows a laminated electrophotographic photosensitive member according to a second embodiment of the present invention. Note that the same parts as those already described in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. Referring to FIG. 2, the electrophotographic photoreceptor of the second embodiment is a positively charged photoreceptor based on a reversal development method, and includes an intermediate layer (insulating layer) 5, a charge transport layer 2, Generation layer 3,
An intermediate layer (insulating layer) 5, a charge transport layer 2, a charge generation layer 3, and a surface protection layer 4 are provided on the conductive substrate 1.
Are sequentially formed.

As described above, according to the second embodiment, the surface protective layer 4 is coated with a composition mainly containing silica particles, an organic compound chemically bonded to the silica particles, and a photopolymerization initiator. By adding a charge transporting material to the cured layer or the surface protective layer 4, it is possible to provide an electrophotographic photosensitive member having high printing durability and scratch resistance and satisfying electrophotographic characteristics. it can.

It is apparent that the present invention is not limited to the above embodiments, and that the embodiments can be appropriately modified within the scope of the technical idea of the present invention. Further, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiment,
The number, position, shape, and the like suitable for carrying out the present invention can be obtained.

[0046]

(Example 1) A charge transporting material represented by the following formula (1)
The tristyryltriphenylamine compound represented by 4) and a polycarbonate as a binder resin (for example, Z
-400, manufactured by Mitsubishi Gas Chemical Co., Ltd.) is dissolved in tetrahydrofuran (hereinafter referred to as THF) solvent, and the plate-type alumite substrate 1 is immersed in a paint for the charge transport layer 2 to form a coating film (for example, about 20 μm). Was formed to form the charge transport layer 2.

[0047]

Embedded image

On the charge transport layer 2, titanyl phthalocyanine (hereinafter referred to as TiOPc) as a charge generating material and polyvinyl butyral resin (for example, B
X-1 (manufactured by Sekisui Chemical Co., Ltd.) was dispersed in a THF solvent, and a coating material (approximately 0.25 μm) was formed by applying a paint for the charge generation layer 3 prepared by dipping.

Subsequently, a stock solution (eg, Desolite Z750) containing silica particles and a composition mainly containing an organic compound chemically bonded to the silica particles and a photopolymerization initiator is used.
Isopropyl alcohol was added to the mixture and diluted with stirring to prepare a coating for the surface protective layer. The paint for the surface protective layer was applied on the charge generation layer 3 by a dipping method. After drying at about 90 ° C for about 20 minutes, use a low-pressure mercury lamp to emit ultraviolet light for 1 minute.
Irradiated for about 1 minute to form a surface protective layer 4 having a thickness of about 1 μm, thereby producing a laminated electrophotographic photosensitive member.

Example 2 The following formula (1) was used for the charge transport material.
A laminated electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the butadiene derivative shown in 5) was used.

[0051]

Embedded image

Example 3 The following formula (1) was used for the charge transport material.
A laminated electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the hydrazone derivative shown in 6) was used.

[0053]

Embedded image

Example 4 The following formula (1) was used for the charge transporting material.
A laminated electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the stilbene derivative shown in 7) was used.

[0055]

Embedded image

Example 5 A laminated electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that τ-type non-metallic phthalocyanine (hereinafter referred to as τ-H ₂ Pc) was used as the charge generating material. .

(Embodiment 6) τ-H ₂ Pc
A laminated electrophotographic photoreceptor was prepared in the same manner as in Example 2 except for using.

(Embodiment 7) τ-H ₂ Pc
A laminated electrophotographic photoreceptor was prepared in the same manner as in Example 3 except for using.

(Embodiment 8) τ-H ₂ Pc
A laminated electrophotographic photoreceptor was prepared in the same manner as in Example 4 except for using.

(Comparative Example 1) (Photoreceptor without Surface Protective Layer 4) A laminated electrophotographic photoreceptor was prepared in the same manner as in Example 3 except that the surface protective layer 4 was not provided.

Comparative Example 2 Photosensitive Member without Surface Protective Layer 4 A laminated electrophotographic photosensitive member was prepared in the same manner as in Example 8, except that the surface protective layer 4 was not provided.

An electrostatic charging test apparatus (for example, EPA-8) for measuring the surface potential behavior of these flat electrophotographic photosensitive members by repeating a charging-exposure-discharging process to measure the surface potential of the photosensitive members.
200, manufactured by Kawaguchi Electric Works), the measurement conditions were room temperature and normal humidity, the corona charging voltage was about 8 kV, and the white exposure was 5.0.
The evaluation of electrophotographic characteristics was performed with Lux approximately. Furthermore,
After immersing the photoreceptors prepared in Examples and Comparative Examples in an aliphatic hydrocarbon (dodecane) for one week, the photoreceptor surface was observed. Table 1 shows the results of these evaluations.

[0063]

[Table 1]

Example 9 A coating film (30) was formed on a disc-shaped alumite substrate by using the same charge transport layer paint as in the first example.
μm) to form the charge transport layer 2. Then the first
A surface protection layer 4 is formed on the charge transport layer 2 in the same manner as in the embodiment.
Was formed to prepare a disk-shaped substrate for abrasion test.

Comparative Example 3 (Abrasion Test Substrate without Surface Protective Layer 4) A disk-shaped abrasion test substrate was prepared in the same manner as in the ninth embodiment except that the surface protective layer 4 was not formed. The amount of film abrasion of these disc-shaped abrasion test substrates was measured using a tapered abrasion tester (manufactured by Toyo Seiki Co., Ltd., wear wheel MS-10, additional load 500 g, 1000 rotations). Table 2 shows the evaluation results.

[0066]

[Table 2]

[0067]

According to the present invention, the surface protective layer is coated with a composition mainly containing silica particles, an organic compound chemically bonded to the silica particles, and a photopolymerization initiator. By adding a charge transporting material to the layer formed by curing or the protective layer, it is possible to provide an electrophotographic photosensitive member having high printing durability and scratch resistance and satisfying electrophotographic characteristics.

[Brief description of the drawings]

FIG. 1 is a laminated electrophotographic photosensitive member according to a first embodiment of the present invention.

FIG. 2 shows a laminated electrophotographic photosensitive member according to a second embodiment of the present invention.

[Description of Signs] 1 ... conductive substrate 2 ... charge transport layer 3 ... charge generation layer 4 ... surface protective layer 5 ... intermediate layer

Claims (10)

[Claims] 1. A positively charged electrophotographic photoreceptor for use in a reversal development system using a positively charged liquid toner or a powdery toner, wherein silica particles and organic compounds chemically bonded thereto are formed on a charge generation layer. A surface protection layer formed by applying and curing a composition mainly containing a compound and a photopolymerization initiator, wherein the organic compound of the surface protection layer is a polymerizable unsaturated group represented by formula (1) or (2) Wherein X is selected from -NH-, -O- and -S-, and Y is selected from oxygen and sulfur atoms, provided that when X is -O-, Y is a sulfur atom. An electrophotographic photoreceptor characterized in that the silica particles and the organic compound are bonded via a silyloxy group. Embedded image Embedded image 2. The method according to claim 1, wherein the thickness of the surface protective layer is 0.5 to 10 μm.
2. The electrophotographic photosensitive member according to claim 1, wherein the value is set to about m. 3. The electrophotographic photoreceptor according to claim 1, wherein the surface protective layer is mainly photo-cured using ultraviolet light having a wavelength of about 310 nm or less. 4. A photoreceptor of a positive charging type by a reversal development method, a conductive substrate functioning as an electrode of the photoreceptor and functioning as a support for another layer, and formed on the conductive substrate. The electrophotographic photoreceptor according to any one of claims 1 to 3, further comprising a charge transport layer, and the charge generation layer formed on the charge transport layer. 5. A photoreceptor of a positive charging type by a reversal development method, a conductive substrate functioning as an electrode of the photoreceptor and functioning as a support for another layer, and formed on the conductive substrate. 4. An adhesive layer, comprising: a charge transport layer formed on the adhesive layer; and the charge generation layer formed on the charge transport layer. 2. The electrophotographic photoreceptor of claim 1. 6. A method for producing a positively charged photosensitive drum for use in a reversal development system using a positively charged liquid toner or a powder toner, wherein a silica particle and an organic compound chemically bonded to the silica particle are formed on the charge generation layer. A step of applying and curing a composition mainly containing a compound and a photopolymerization initiator to form a surface protective layer, wherein the organic compound of the surface protective layer comprises a polymerizable unsaturated group represented by formula (3) or (4) (wherein, X is selected from -NH-, -O- and -S-, and Y is selected from an oxygen atom and a sulfur atom, provided that when X is -O-, Y is a sulfur atom) Wherein the silica particles and the organic compound are bonded via a silyloxy group. Embedded image Embedded image 7. The film thickness of the surface protective layer is 0.5 to 10
7. The method according to claim 6, further comprising the step of setting the diameter to about [mu] m. 8. The method according to claim 6, further comprising the step of photo-curing the surface protective layer mainly using ultraviolet light having a wavelength of about 310 nm or less. 9. a step of forming the positively charged photoreceptor by a reversal development method, and a step of forming a conductive substrate functioning as an electrode of the photoreceptor and functioning as a support for another layer. The method according to claim 6, further comprising: forming a charge transport layer on the conductive substrate; and forming the charge generation layer on the charge transport layer. Photosensitive drum making method. 10. A step of forming the positively charged photoconductor by a reversal development method, and a step of forming a conductive substrate functioning as an electrode of the photoconductor and functioning as a support for another layer. A step of forming an adhesive layer on the conductive substrate; a step of forming a charge transport layer on the adhesive layer; and a step of forming the charge generation layer on the charge transport layer. The method for producing a photosensitive drum according to claim 6.