JP2003066642A - Electrophotographic photoreceptor and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor and a method for manufacturing the photoreceptor having high printing durability, scratch resistance and resistance against environmental changes. SOLUTION: In the electrophotographic photoreceptor having a surface protective layer 5, the surface protective layer 5 comprises a layer formed by applying and hardening a composition essentially containing silica particles and a photopolymerization initiator. The silica particles are coupled through silyloxy groups with an organic compound having one or more kinds of groups selected from polymerizable unsaturated groups and groups expressed by formula (4) and by formula (5). Further, a chemical adsorption film 6 is formed on the surface of the surface protective layer 5 through siloxane bonds by using at least one kind in organosilane compounds.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member having a surface protective layer and a method for manufacturing the same, and more particularly to an electrophotographic photosensitive member used in a copying machine, a printer or the like using an electrophotographic recording system and its manufacturing. Regarding the method.

[0002]

2. Description of the Related Art In recent years, as a photoconductor for electrophotography, organic photoconductive materials have been widely used because they have advantages of wide selection of materials and high productivity. Electrophotographic photoreceptors using these organic photoconductive materials are often used as function-separated photoreceptors in which a charge generation layer and a charge transport layer are laminated in order to satisfy both sensitivity and mechanical properties. .

On the other hand, as a matter of course, the electrophotographic photosensitive member is required to have predetermined sensitivity, electric characteristics, and optical characteristics according to the electrophotographic process to be applied. Particularly, the surface layer of an electrophotographic photosensitive member that can be repeatedly used is directly applied with an external electric or mechanical force such as corona charging, toner development, transfer to paper or cleaning treatment, and therefore high durability against them is required. . Specifically, due to deterioration caused by ozone generated during corona charging, durability in terms of electrical characteristics such as sensitivity decrease, potential decrease, and residual potential increase, and chemical resistance against toner stain due to surface energy increase. Or mechanical durability against abrasion or damage of the photoreceptor due to rubbing.

Conventionally, for the purpose of improving the electrical and chemical durability, there has been disclosed a technique of providing a chemical adsorption film of an organosilane compound or a protective layer of a photocurable resin on the surface of an electrophotographic photosensitive member. . For example, JP-A-5-27
Japanese Patent Laid-Open No. 472 (hereinafter referred to as "prior art 1") discloses a technique for forming a chemisorption monomolecular film via a siloxane bond containing a fluoroalkyl group on the surface of an electrophotographic photosensitive member. According to the method of Prior Art 1, since the chemisorption monomolecular film is excellent in antifouling property and durability and is a very thin film of nanometer to angstrom unit, the characteristics of the electrophotographic photoreceptor surface are not impaired. I am trying.

Further, in Japanese Patent Laid-Open No. 2000-10321 (hereinafter referred to as "prior art 2"), 1 selected from a polymerizable unsaturated group and groups represented by the above formulas (4) and (5). A technique of forming a surface protective layer by coating and curing a composition mainly containing silica particles bonded to an organic compound having at least one species through a silyloxy group and a photopolymerization initiator is disclosed. According to the composition of Prior Art 2, an electrophotographic photosensitive member having a surface protective layer excellent in electrophotographic characteristics, durability and printing durability can be efficiently produced with high yield.

[0006]

However, in the prior arts 1 and 2 described above, the film stability, adhesion, mechanical durability, moisture resistance, and anti-proof property, which are the properties required for the electrophotographic photoreceptor protective layer, are provided. The stain resistance and the like were not necessarily compatible with each other, and each characteristic and productivity could not be sufficiently satisfied. For example, in the example described in Related Art 1, an example is described in which after oxygen plasma treatment, tetrachlorosilane treatment is performed in a nitrogen atmosphere, and a chemisorption film of an organosilane compound containing a fluorinated alkyl group is formed. However, this requires a complicated process using a silane compound having poor storage stability and corrosivity, and is inferior in productivity.

Further, in the case of forming such a chemisorption monomolecular film via a siloxane bond, if the hardness of the substrate to be treated is not sufficient, the mechanical strength is poor. Further, the hydrolyzable organosilane usually forms a chemisorption film by forming a siloxane bond with the hydroxyl group of the substrate to be treated, but in the organophotoreceptor before the surface protective layer is formed, the charge transport layer usually has a charge Since the transport material is dispersed in a resin such as polycarbonate and there are very few hydroxyl groups on the surface, it is necessary to increase the number of hydroxyl groups by subjecting the photoreceptor to pretreatment such as oxygen plasma treatment. Such pretreatments such as oxygen plasma and corona discharge not only increase the number of treatment steps but also impair the potential characteristics of the photoconductor.

Regarding the bond at the interface between the substrate to be treated and the chemisorption film of the organosilane compound, Si--O--
Although the Si bond is extremely stable, the Si—O—C bond is easily hydrolyzed, and since a normal organic photoreceptor other than amorphous silicon does not have a silicon atom in the surface layer, even after the chemisorption monomolecular film is formed. However, there is a problem that the film stability is poor.

On the other hand, the coating material as shown in the prior art 2 is excellent in hardness, film stability, and potential characteristics, but still has a large surface energy, so that toner stains are likely to occur. Furthermore, a silanol group,
Water in the air is easily adsorbed because it has hydrophilic sites such as urethane bonds, and the electrical conductivity of the protective layer fluctuates depending on humidity, so the environmental changes in the potential characteristics are large, and image deletion occurs at high temperature and high humidity. There are problems such as.

The present invention has been made in view of the above conventional problems, and has high printing durability and scratch resistance, is excellent in productivity, film stability, and potential characteristics, and is affected by environmental changes. It is an object of the present invention to provide an electrophotographic photoconductor that is less susceptible to damage and a method for manufacturing the same.

[0011]

The electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor having a surface protective layer, wherein the surface protective layer comprises a polymerizable unsaturated group, the above formula (4) and the above formula ( 5) formed by coating and curing a composition mainly containing silica particles bonded to an organic compound having at least one selected from the group represented by 5) through a silyloxy group, and a photopolymerization initiator And a chemical adsorption film via a siloxane bond on the surface of the surface protective layer, using at least one of the organosilane compounds having the general structure of the above formulas (1) to (3). It is provided (Claim 1). (However, the above formula (1)
In the formula (3), R ₁ , R ₂ and R ₃ are organic functional groups, and X ₁ , X ₂ and X ₃ are leaving groups. Further, in the above formula (4), X is selected from —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. ) Examples of the polymerizable unsaturated group include an acryloxy group,
Methacryloxy group, vinyl group, propenyl group, butadienyl group, styryl group, ethynyl group, cinnamoyl group,
Examples thereof include a maleate group and an acrylamide group, and an acryloxy group is particularly preferable. The above general formula (4)
Examples of the group represented by are the groups represented by the following formulas.

[Chemical 6] The photopolymerization initiator is preferably selected from compounds capable of generating active radical species upon irradiation with ultraviolet rays, and is added in an amount of 0.1 to 10 parts by weight, preferably 1 to 100 parts by weight of the solid content of the curable composition. To 5 parts by weight.
If the amount of the photopolymerization initiator added is 0.1 parts by weight or less, the polymerization is not performed, and if it exceeds 10 parts by weight, the film strength and the potential characteristics of the electrophotographic photosensitive member may be impaired. The solvent for diluting the composition mainly containing the silica particles and the organic compound chemically bonded to the silica particles and the photopolymerization initiator is not particularly limited, but in consideration of solubility, drying property, etc. , Methanol, isopropyl alcohol, etc.,
An alcohol solvent having a boiling point of 120 ° C. or lower is preferable. If the boiling point of the solvent exceeds 120 ° C., the solvent may remain in the surface protective layer under the drying temperature condition that does not deteriorate the characteristics of the electrophotographic photoreceptor, and the potential characteristics of the electrophotographic photoreceptor may be impaired. If it is dried for a long time to avoid it, the productivity will be reduced. A charge transport material can be added to the surface protective layer in order to improve the potential characteristics. In this case, the addition amount of the charge transport material is not particularly limited. After coating these surface protective layer coating materials on the photoreceptor, it is dried and irradiated with ultraviolet rays to be cured to obtain a photoreceptor having a surface protective layer. Considering the potential characteristics and film forming property of the photoreceptor, the drying temperature is preferably 60 ° C. or higher and 120 ° C. or lower, and the thickness of the protective layer is preferably 0.5 μm or more and 10 μm or less.
It is not particularly limited. In the organosilane compound having the general structure of the above formulas (1) to (3), the organic functional groups R ₁ , R ₂ and R ₃ have a low surface energy when the electrophotographic photosensitive member surface after the chemical adsorption film formation, It is also selected to be hydrophobic, and the contact angle of water on the surface of the electrophotographic photosensitive member is preferably 60 ° or more. By providing a chemical adsorption film made of an organosilane compound having a contact angle of water of 60 ° or more on the surface protective layer,
It is possible to reduce the surface energy and prevent the image flow due to the adsorption of water at high temperature and high humidity, and the stain and filming due to the toner. At least one of these has a long-chain alkyl group such as an octyl group, a dodecyl group, or an octadecyl group, or a fluorinated alkyl group represented by the above formulas (6) and (7), or a perfluoropolyether group. It is preferably an organic functional group. Here, in the formula (6), n is preferably an integer of 3 to 25 from the viewpoint of the surface treatment effect and the solubility in a solvent. Further, in the above formula (7), R _f represents a perfluoropolyether group, R ₄ represents an atom or atomic group of any one of O, NH and S, and R ₅ is an alkylene chain having no particular limitation on the number of carbon atoms. Indicates. As R _f , a repeating unit structure represented by the following formula is preferable, and the molecular weight is not particularly limited, but a number average molecular weight of 500 to 2000 is preferable in terms of stability and easiness of handling. (Where k,
l, m and n represent integers of 1 or more. )

[Chemical 7] Further, even if two or more of the organic functional groups R ₁ , R ₂ and R ₃ are any one of a methyl group, an ethyl group, a propyl group, a butyl group and a phenyl group, the same effect can be obtained at low cost. . On the other hand, from the viewpoint of reactivity and mass productivity, the leaving group X
_At least one of ₁ , X ₂ and X ₃ is preferably an organic compound bonded via a hydrogen atom, a halogen, an alkoxy group, or a nitrogen atom. However, in the case of hydrogen atom, hydrogen is generated during storage and use, so there is a risk of ignition and explosion.In the case of halogen such as chlorine atom and bromine atom, the pot life is short due to high reactivity, so storage and use Occasionally, corrosive hydrogen halide is generated, which causes corrosion and deterioration of the substrate to be treated and production equipment, which is also a problem in terms of safety. Therefore, it is more preferable to use either an alkoxy group such as a methoxy group or an ethoxy group, or an organic compound bonded through a nitrogen atom such as a dimethylamino group or a trimethylsilylamino group. As an organosilane compound that is easy to obtain, has high safety and high treatment effect,
Examples thereof include a trialkoxysilane having a perfluoropolyether group, octadecyltriethoxysilane, hexamethyldisilazane, heptadecafluorodecyltrimethoxysilane, diethoxydimethylsilane, dimethoxydiphenylsilane, or a mixture thereof. The method for producing an electrophotographic photosensitive member of the present invention comprises an ultraviolet curing surface treatment step, a chemical adsorption layer treatment step, and a film forming and drying step. In the ultraviolet curing surface treatment step of the surface protective layer, it is preferable to use ultraviolet rays having a wavelength of 310 nanometers (nm) or less. Examples of the ultraviolet lamp used as the light source include a low pressure mercury lamp and a high pressure mercury lamp. By curing the surface protective layer coating material by using ultraviolet rays having a wavelength of 310 nm or less, at the same time, by performing a surface treatment on the cured surface protective layer,
Can be chemically activated. This makes it possible to eliminate the surface treatment process such as the oxygen plasma treatment, which has been conventionally required to form a stable chemisorption layer. As a result, the number of steps can be reduced, and a stable chemical adsorption layer can be produced. An organosilane is used as a manufacturing method in which the surface of the photoreceptor after the surface protection layer is formed is treated with an organosilane compound to form a chemical adsorption film (chemical adsorption layer treatment step), and then film formation drying (film formation drying step) is performed. There are two methods: a method of directly applying and drying the compound and a method of applying and drying the compound after dissolving it in an organic solvent. A method of directly coating and drying an organosilane compound having a low boiling point, such as hexamethyldisilazane, does not require a solvent, and the unreacted organosilane compound that causes stickiness and increase in surface energy is volatilized, so that the treatment is performed uniformly. Can be advantageously performed. Considering the processing conditions that do not impair the potential characteristics of the photoconductor, it is preferable that the organosilane compound is directly applied to the electrophotographic photoconductor and dried. On the other hand, when the photoreceptor is treated with an organosilane compound having a high boiling point, such as octadecyltriethoxysilane and heptadecafluorodecyltrimethoxysilane, any of water, alcohol, aromatic, alkane, ether, and fluorine-based compounds can be used. Or
Alternatively, it is preferable that a solution in which the organosilane compound is dissolved in these mixed solvents at a concentration of 0.1 to 10 weight percent is applied to the electrophotographic photosensitive member and dried.
When the concentration of the organosilane compound is 0.1% by weight or less, the chemical adsorption film has a defect, so that there is almost no treatment effect, and when it is 10% by weight or more, a large amount of unreacted organosilane compound remains and becomes sticky. , Which causes an increase in surface energy. The boiling point of the solvent is preferably 120 ° C. or lower in consideration of the upper limit of the temperature at which the characteristics of the electrophotographic photoreceptor are not deteriorated, the residual solvent and the drying time. The above-mentioned organosilane compound forms a covalent bond with a silanol group on the outermost surface of the surface protective layer, and when the number of leaving groups is 3 or more, it is hydrolyzed by drying in air,
It forms siloxane bonds between the molecules to form a strong network polymer. Examples of the coating method include, but are not limited to, dip coating, spray coating and blade coating. In any of the above processing methods, the drying temperature in the film-forming drying step is 60 ° C. or higher and 120
The temperature is preferably not higher than 0 ° C., and the chemical adsorption layer is chemically bonded at the same time when the solvent is dried. As a drying treatment method,
Examples include constant temperature warm air drying, infrared drying, microwave dielectric heating drying and the like. If the drying temperature is too high, problems such as cracking of the electrophotographic photoreceptor supporting substrate and deterioration of electrophotographic characteristics occur. Further, if the drying temperature is too low, there are problems such as residual solvent remaining, productivity is reduced due to longer drying time, and the chemisorption film is partially biased due to the surface tension of the solvent during drying, resulting in film defects. Occur. The thickness of the chemisorption film of the organosilane compound is 0.4 n.
It is preferably m or more and 50 nm or less. The thickness of the chemisorption film made of an organosilane compound is about 0.4 to 0.5 nm in the case of a monomolecular film, considering the organosilane compound having the smallest methyl group, and about 2 to 3 nm for a large octadecylsilane. is there. Therefore, 0.
There is no chemisorption film composed of an organosilane compound having a thickness of less than 4 nm. Further, the chemical adsorption film may be a multi-layer molecular film, but if the film thickness is too thick, electrophotographic characteristics are deteriorated, and the unreacted organosilane compound causes stickiness and increases surface energy. Therefore, by setting the thickness of the chemisorption film to 0.4 nm or more and 50 nm or less, a stable chemisorption film can be formed without impairing the electrophotographic characteristics. The electrophotographic photosensitive member of the present invention has R _{1 to} R _{3 in the} above formulas (1) to (3).
At least one of which is treated with an organosilane compound having an octyl group, a dodecyl group or an octadecyl group (claim 2). Further, the electrophotographic photosensitive member of the present invention has R in the above formulas (1) to (3).
_{It is characterized in that} two or more of _{1 to} R ₃ are treated with an organosilane compound having at least one of a methyl group, an ethyl group, a propyl group, a butyl group and a phenyl group (claim 3). The electrophotographic photoreceptor of the present invention has the formula (1) above.
To the formula (3), at least one of R _{1 to} R ₃ is an organofunctional group represented by the formula (6) and the formula (7), which is an organic functional group having a fluorinated alkyl group or a perfluoropolyether group. It is characterized by being treated with a silane compound (claim 4). In addition, the electrophotographic photosensitive member of the present invention has the formula (1) to the formula (3), X _{1 to} X
_At least one of ₃ is treated with an organosilane compound having an alkoxy group (claim 5). The electrophotographic photosensitive member of the present invention is treated with an organosilane compound which is an organic compound in which at least one of X _{1 to} X _{3 in} the above formulas (1) to (3) is bonded via a nitrogen atom. (Claim 6). The electrophotographic photoreceptor of the present invention is characterized in that the organosilane compound is heptadecafluorodecyltrimethoxysilane or a trialkoxysilane having a perfluoropolyether group (claim 7). Also,
The electrophotographic photosensitive member of the present invention, the organosilane compound,
It is octadecyltriethoxysilane (claim 8). Further, the electrophotographic photoreceptor of the present invention is characterized in that the organosilane compound is any one of hexamethyldisilazane, diethoxydimethylsilane, dimethoxydiphenylsilane, or a mixture thereof. 9). Further, the electrophotographic photoreceptor of the present invention is characterized in that the contact angle of water on the surface of the chemical adsorption film of the organosilane compound is 60 ° or more (claim 10). Further, in the electrophotographic photosensitive member of the present invention, the chemical adsorption film of the organosilane compound has a thickness of 0.4.
The thickness is not less than 50 nm and not more than 50 nm (claim 11). The method for producing an electrophotographic photosensitive member of the present invention is a UV-curing surface treatment step of curing the surface protective layer coating applied on the photosensitive member with ultraviolet rays having a predetermined wavelength or less, and an organosilane compound is directly coated on the photosensitive member. And a film forming and drying step of drying the organosilane compound to chemically bond the chemical adsorption layer onto the surface protective layer (claim 12). The method for producing an electrophotographic photosensitive member of the present invention comprises an ultraviolet-curing surface treatment step of curing the surface protective layer coating material applied on the photosensitive member with ultraviolet rays having a predetermined wavelength or less, and diluted to a predetermined concentration with a predetermined diluent solvent. Characterized by comprising a chemical adsorption layer treatment step of applying the prepared organosilane compound on the photoreceptor, and a film formation drying step of drying the dilution solvent to chemically bond the chemical adsorption layer on the surface protective layer. (Claim 13).
In the method for producing an electrophotographic photosensitive member of the present invention, the diluting solvent in the chemical adsorption layer treatment step is any one of water, alcohols, alkanes, aromatics, ethers, fluorines, or a mixed solvent thereof. (Claim 14). Further, the method for producing an electrophotographic photosensitive member of the present invention is characterized in that the concentration of the organosilane compound solution in the chemical adsorption layer treatment step is 0.1% by weight or more and 10% by weight or less (claim 1).
5). Further, the method for producing an electrophotographic photosensitive member of the present invention is characterized in that in the film forming and drying step, the film is dried at 60 ° C. or higher and 120 ° C. or lower (claim 16). Further, the method for producing an electrophotographic photosensitive member of the present invention is characterized in that the ultraviolet rays in the ultraviolet curing surface treatment step have a wavelength of 310 nm or less (claim 17). An electrophotographic apparatus of the present invention comprises the electrophotographic photoreceptor according to any one of claims 1 to 11, a charging unit, an exposing unit, a developing unit, and a transferring unit (Claim). Item 1
8). The electrophotographic photoreceptor of the present invention is excellent in productivity, mechanical strength, film stability, and potential characteristics, but on the other hand, it is the most effective surface protective layer having a hydrophilic group that adsorbs moisture such as silanol group and increases surface energy. By providing a chemical adsorption film using an organosilane compound on the surface through a siloxane bond, the surface energy is lowered and the hydrophobicity is improved, so that contamination by toner and environmental fluctuation of potential characteristics are prevented. . That is, by weakening the interaction between the toner and the outermost surface of the surface protective layer and preventing the adsorption of water contained in the air, it is possible to provide a photoreceptor having excellent antifouling properties and suppressing environmental fluctuations in potential characteristics. Further, since the surface protective layer has sufficient hardness and contains silica particles in which an organic compound is bonded via a silyloxy group, a large number of silanol groups are present on the surface, and the base of the chemisorption film is formed. Is formed by a covalent bond with the silanol group via a siloxane bond, so that a film having excellent durability can be obtained. Further, since the chemisorption film of the present invention is an extremely thin film, which is usually in the range of nanometer to angstrom,
It has almost no effect on the light transmission characteristics and potential characteristics of the photoconductor. As described above, the surface protective layer is formed by selecting a material having a silanol group having excellent potential characteristics and mechanical strength and treating it with an organosiloxane compound that chemically bonds with the silanol group to form a chemisorption film. It is possible to drastically extend the durability of the chemically adsorbed layer thus prepared and manufacture a stable photoconductor.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a laminated electrophotographic photosensitive member which is an embodiment of the present invention. The laminated electrophotographic photosensitive member 1 of this example comprises a charge generating layer 3, a charge transport layer 4, a surface protective layer 5, and a chemical adsorption film 6 of an organosilane compound on a conductive substrate 2. The conductive substrate 2 is
It serves as an electrode of the electrophotographic photosensitive member and at the same time serves as a support for other layers, and may have any shape such as a cylindrical shape, a plate shape, or a film shape. The material of the conductive substrate 2 is not limited,
Not only a metal such as aluminum, stainless steel, nickel, but also an insulating substrate such as glass or plastic which has been subjected to a conductive treatment with a vapor deposition film of aluminum or gold, a coating film of a conductive polymer, or the like may be used. On this conductive substrate, an anodic oxide film such as Al ₂ O ₃ is usually formed, or an undercoat layer made of polyamide resin or the like is formed. When the undercoat layer is formed, its thickness is preferably 0.1 μm or more and 1 μm or less.

The charge generation layer 3 is formed of a vapor-deposited film of an organic photoconductive substance or a coating film in which an organic charge generation substance is dispersed in a binder resin, and is irradiated with light having a predetermined wavelength to form a charge generation material. When light is received, an electric charge is generated. As the charge generating substance, a phthalocyanine compound such as a metal-free phthalocyanine, a copper phthalocyanine, or a titanyl phthalocyanine, a pigment such as an azo pigment or a polycyclic quinone is used, and a suitable material depending on the wavelength of a light source used and a charge transport substance. Is selected. The film thickness of the charge generation layer 3 is sufficient to absorb the light from the light source and generate a charge amount necessary for canceling the charges formed on the photoconductor by corona discharge or the like. It is determined by conditions such as coefficient, dispersion amount in binder resin, or generation efficiency. Generally less than 3 μm, preferably 0.1 μm
It is 1 μm or less.

The charge transport layer 4 is formed of a coating film of a material in which an organic charge transport substance is dispersed in a binder resin.
The charge transport layer 4 functions as an insulating layer in a dark place, and has a role of holding charges formed by corona discharge or the like on the surface of the photoconductor. Further, the charge generation layer 3 has a property of transmitting a sensitive light, and has a function of transporting the charges generated and injected in the charge generation layer 3 at the time of exposure and neutralizing and eliminating the charges on the surface of the photoreceptor. As the charge transport material, a hydrazone compound,
Organic compounds such as triphenylmethane compounds, triphenylamine compounds, and butadiene compounds are used. Materials such as polycarbonate resin, polyester resin, polyamide resin, polyurethane resin, silicone resin, and epoxy resin are used as the binder resin, and have mechanical durability, chemical stability, electrical stability, and adhesion with other layers. And compatibility with the charge transport material used. The film thickness of the charge transport layer 4 is determined by requirements such as the charge retention rate, the speed of the charge transport rate, and the mechanical durability, and is generally 50 μm or less, preferably 10 μm or more and 30 μm or less.
m or less.

The surface protective layer 5 is provided to enhance the durability and printing durability of the photoconductor. It has the ability to withstand mechanical friction caused by cleaning, etc., has the function of holding the charges generated by corona discharge, etc. on the surface in the dark, and has the ability to transmit the light that the charge generation layer 3 is sensitive to. is doing. A charge transport material may be added to reduce the electric resistance and improve the electrophotographic characteristics.
The suitable film thickness of the surface protective layer 14 varies greatly depending on the developing method and the required performance, but is generally 10 μm or less, preferably 0.5 μm or more and 5 μm in the contact developing method.
It is the following. For a photoreceptor that requires a large area, 0.
When the thickness is 5 μm or less, it is difficult to form a film having a uniform film thickness that does not cause image unevenness, and the durability and printing durability with respect to the developing roller and paper become low. Further, when it exceeds 5 μm, the electrophotographic characteristics are largely deteriorated, and specifically, problems such as an increase in residual potential and a decrease in sensitivity occur, which makes it unsuitable for practical use as a photoreceptor.

The chemical adsorption film 6 made of an organosilane compound is provided in order to enhance the antifouling property of the photoconductor and suppress the environmental fluctuation of the potential characteristics. It forms a covalent bond with the silanol group existing on the surface of the underlying surface protective layer 5, and the leaving group is 3
In one case, intermolecular condensation forms a network polymer. Since the surface protective layer 5 is sufficiently hard, the chemical adsorption film 6 can sufficiently withstand mechanical friction and the like. The film thickness of the chemical adsorption film 6 made of an organosilane compound is 0 in consideration of the range where the adsorption of toner and water is suppressed and the potential characteristics are not impaired.
It is preferably about 4 to 50 nanometers (nm).

In the above, as one embodiment, the charge generation layer 3, the charge transport layer 4, the surface protection layer 5, and the chemical adsorption film 6 made of an organosilane compound are applied and laminated in this order on the conductive substrate 2 made of aluminum, for example. The laminated electrophotographic photosensitive member 1 has been described above, but the structure of the electrophotographic photosensitive member of the present invention is not limited to these. For example, it is also applicable as a photoreceptor structure in which a charge transport layer 4, a charge generation layer 3, a surface protective layer 5, and a chemical adsorption film 6 made of an organosilane compound are laminated in this order on a conductive substrate 2. Further, it is possible to disperse a charge generating material in a photocurable resin to form a charge generating layer regardless of whether the photosensitive body is positively charged or negatively charged. Further, the organosilane compound is formed on the single-layer type photoreceptor obtained by applying and curing the coating material obtained by mainly mixing the photocurable resin, the charge transport material and the charge generating material on the aluminum substrate. It is also possible to form a chemisorption film.

[0018]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

(Example 1) As the charge generation layer 3, a cylinder having an outer diameter of 30 mm, which was obtained by dissolving a charge generation material titanyl phthalocyanine and a butyral resin which is a binder resin in a tetrahydrofuran (THF) solvent, was subjected to anodic alumite treatment and had an outer diameter of 30 mm. The shaped aluminum substrate 2 was dipped to form a coating film, and the film thickness after drying was set to about 0.3 μm. On the charge generation layer 3 thus obtained, a charge transport material bistriphenylamine styryl compound having the following structure and a binder resin polycarbonate (trade name Z400, manufactured by Mitsubishi Chemical Corporation)
Made in a THF solvent to form a charge transport layer paint, and a coating film is prepared by a dipping method, and the film thickness after drying is about 20 μm.
The charge transport layer 4 was prepared so that

[0020]

[Chemical 8]

Next, 0.5 part by weight of a bistriphenylaminestyryl compound, a charge transporting material which is the same as the compound used in the charge transporting layer, was sufficiently dissolved in 10 parts by weight of a THF solvent with stirring. The obtained concentrated solution of the charge transport material is diluted and dispersed in 40 parts by weight of isopropyl alcohol, and further contains a composition containing mainly silica particles, an organic compound chemically bonded thereto and a photopolymerization initiator. Desolite KZ7861 (manufactured by JSR) as (solvent: methanol / isopropyl alcohol mixed solvent) 50
Parts by weight were added and sufficiently stirred to prepare a surface protective layer coating material.

The surface protective layer coating material thus obtained was dip-coated on the photosensitive member prepared up to the charge transport layer 4. After drying at 60 ° C. for 10 minutes, ultraviolet rays were radiated for 3 minutes using a low pressure mercury lamp to prepare a surface protective layer 5 having a film thickness of about 1 μm, and at the same time, the silanol groups existing on the surface were activated.
Through the above steps, the electrophotographic photosensitive member 7 having the surface protective layer 5 as shown in FIG. 2 was obtained.

On the surface protective layer 5 thus obtained, a solution of 1 part by weight of octadecyltriethoxysilane in 100 parts by weight of hexane was applied by dipping and then applied at 100 ° C.
A chemical adsorption film 6 made of organosilane was produced by drying for 1 hour to obtain an electrophotographic photoreceptor 1 of the present invention.

(Example 2) 100 parts by weight of m-xylene hexafluoride, 3 parts by weight of heptadecafluorodecyltriethoxysilane were placed on the electrophotographic photosensitive member 7 prepared up to the surface protective layer 5 under the same conditions as in Example 1. The solution in which was dissolved was applied by dip coating, and then dried at 100 ° C. for 1 hour to prepare a chemisorption film 6 made of organosilane.

Example 3 Hexamethyldisilazane was dip-coated on the electrophotographic photosensitive member 7 prepared up to the surface protective layer 5 under the same conditions as in Example 1, and then dried at 100 ° C. for 1 hour to obtain an organosilane. A chemical adsorption film 6 made of was prepared.

Comparative Example 1 After the charge transport layer 4 was prepared under the same conditions as in Example 1, 100 parts by weight of m-xylene hexafluoride and 3 parts by weight of heptadecafluorodecyltriethoxysilane were formed on the charge transport layer 4. This is a photoreceptor on which a chemisorption film 6 made of organosilane was produced by dipping and coating a solution in which parts are dissolved and then drying at 100 ° C. for 1 hour.

(Comparative Example 2) An electrophotographic photosensitive member 7 was prepared up to the surface protective layer 5 under the same conditions as in Example 1.

The contact angles of water on the surfaces of the photoreceptors of Examples 1 to 3 and Comparative Examples 1 and 2 were measured.
As shown in Table 1, it was revealed that the photoconductor having the chemically adsorbed film formed of the organosilane compound had a greater hydrophobicity than the photoconductor of Comparative Example 2 having no chemically adsorbed film.

[0029]

[Table 1]

The photoconductors of Examples 1 to 3 and Comparative Examples 1 and 2 were mounted on an NEC printer PC-PR1000, and
When a printing test was performed in a high temperature and high humidity environment of 2.5 ° C. and 80% RH, a high quality image was obtained on the photoconductor on which the chemical adsorption film of the organosilane compound was formed, but the chemical adsorption film was formed. In the photoconductor of Comparative Example 2 which did not, as shown in Table 1, image deletion due to adsorption of water occurred. High-definition images could be formed on any photoreceptor having a contact angle of more than 60 ° regardless of the type of organosilane compound.

Further, in a printer equipped with the above-mentioned photosensitive member, a continuous printing test of 20,000 sheets was conducted at 20 ° C. and 40%.
When carried out in a room temperature and normal humidity environment of RH, as shown in Table 1, with the photoreceptors of Examples 1 to 3, high-quality images were obtained as in the initial stage, and without surface treatment such as oxygen plasma,
It was confirmed that a stable chemically bonded chemisorption film was formed. However, although the photoreceptor of Comparative Example 1 has a chemically adsorbed film of an organosilane compound, it lacks a hard surface protective layer containing silanol groups, and thus has poor film stability and durability.
Image fogging occurred due to wear of the charge transport layer. On the other hand, in the photoconductor of Comparative Example 2 in which the chemisorption film was not formed, the surface energy was large, and thus the image defect due to the filming of the toner was observed.

[0032]

According to the present invention, the surface protective layer is made of a material having a silanol group which is excellent in potential characteristics and mechanical strength and which forms a stable chemical bond with the silanol group. By forming a silane compound as a chemisorption film, the durability of the chemisorption layer is dramatically increased, and it has excellent mechanical strength, film stability, and antifouling properties, and image quality is less susceptible to environmental changes. You can get the body. Furthermore, the conventional pretreatment of the substrate to be treated,
Since it is not necessary to form an adhesive layer or the like and is included in the surface protective layer forming step, it becomes possible to produce a highly durable photoreceptor with a high yield. According to the invention of claim 10, the contact angle of water on the surface of the electrophotographic photosensitive member is 60 ° or more. By providing a chemical adsorption film made of an organosilane compound having a contact angle of water of 60 ° or more on the surface protective layer, the surface energy is reduced, image flow due to adsorption of water at high temperature and high humidity, and toner. It is possible to prevent stains and filming due to. According to the invention of claim 11, the thickness of the chemical adsorption film made of the organosilane compound is 0.4 nm or more and 50 nm or less. The thickness of the chemisorption film made of an organosilane compound is about 0.4 to 0.5 nm in the case of a monomolecular film, considering the organosilane compound having the smallest methyl group, and about 2 to 3 nm for a large octadecylsilane. is there. Therefore, there is no chemisorption film made of an organosilane compound having a thickness of less than 0.4 nm. Further, the chemical adsorption film may be a multi-layer molecular film, but if the film thickness is too thick, electrophotographic characteristics are deteriorated, and the unreacted organosilane compound causes stickiness and increases surface energy. Therefore, by setting the thickness of the chemisorption film to 0.4 nm or more and 50 nm or less, a stable chemisorption film can be formed without impairing the electrophotographic characteristics. According to the twelfth to thirteenth aspects of the invention, the electrophotographic photosensitive member manufacturing process includes an ultraviolet curing surface treatment process, a chemical adsorption layer treatment process, and a film forming and drying process. In the chemical adsorption layer treatment step, when the boiling point of the organosilane compound is low, the solvent is not necessary to be directly applied and dried, and the unreacted organosilane compound that causes stickiness and increase in surface energy can be volatilized and removed. Therefore, it is preferable. Further, when the boiling point of the organosilane compound is high, it is preferable to dilute and coat the solvent on the solvent and then dry it to volatilize the solvent. By taking this process sequence into consideration, a stable chemical adsorption layer can be formed on the surface protective layer, and the electrophotographic photosensitive member is excellent in yield and has excellent electrophotographic characteristics, printing durability, and image quality. Is produced. According to the invention of claims 14 to 15, the diluent solvent in the chemical adsorption layer treatment step is any one of water, alcohol, alkane, aromatic, ether, fluorine, or a mixed solvent thereof. . By adjusting the concentration of the organosilane compound to 0.1 to 10% by weight, the water and the organic solvent uniformly disperse the organosilane compound, uniformly and sticky on the surface protective layer, and increase the surface energy. The unreacted organosilane compound that causes the phenomenon can be reduced to produce a chemisorption film. According to the invention of claim 16, the drying temperature in the film-forming drying step is 120 ° C. or less. If the drying temperature is too high, problems such as cracking of the electrophotographic photosensitive member support and deterioration of electrophotographic characteristics occur. Further, if the drying temperature is too low, there are problems such as residual solvent remaining, productivity is reduced due to longer drying time, and the chemisorption film is partially biased due to the surface tension of the solvent during drying, resulting in film defects. Occur. By setting the temperature to 60 ° C. or higher and 120 ° C. or lower, the above problem can be solved and a uniform chemisorption film can be stably produced on the surface protective layer. As a result, it is possible to produce an electrophotographic photosensitive member having excellent electrophotographic characteristics, printing durability, and image quality. Claim 1
According to the invention described in 7, the ultraviolet ray having a wavelength of 310 nm or less is used in the ultraviolet ray curing surface treatment step. 31
By using ultraviolet rays having a wavelength of 0 nm or less, the surface protective layer coating material is cured, and at the same time, the cured surface protective layer is subjected to surface treatment to be chemically activated. This makes it possible to eliminate the surface treatment process such as oxygen plasma treatment, which has been conventionally required to form a stable chemisorption layer. As a result,
It is possible to reduce the number of steps and produce a stable chemical adsorption layer.

[Brief description of drawings]

FIG. 1 is a conceptual cross-sectional view in which a surface of an electrophotographic photosensitive member according to an embodiment of the present invention is enlarged to a molecular level.

FIG. 2 is a diagram showing a state before treatment with an organosilane compound,
FIG. 3 is a conceptual sectional view in which the surface of the electrophotographic photosensitive member having a protective layer is enlarged to the molecular level.

[Explanation of symbols]

1 Electrophotographic photoreceptor 2 Conductive substrate 3 Charge generation layer 4 Charge transport layer 5 Surface protection layer 6 Chemical adsorption film made of organosilane compound 7 Electrophotographic photoreceptor having a surface protective layer 8 silanol groups

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tomohiro Masumura             7546 Yasuda, Kashiwazaki City, Niigata Prefecture Niigata Japan             Electric Co., Ltd. (72) Inventor Satoko Yoshida             7546 Yasuda, Kashiwazaki City, Niigata Prefecture Niigata Japan             Electric Co., Ltd. (72) Inventor Shinya Yamamoto             7546 Yasuda, Kashiwazaki City, Niigata Prefecture Niigata Japan             Electric Co., Ltd. (72) Inventor Naoya Maeda             7546 Yasuda, Kashiwazaki City, Niigata Prefecture Niigata Japan             Electric Co., Ltd. (72) Inventor Hiroshi Oue             7546 Yasuda, Kashiwazaki City, Niigata Prefecture Niigata Japan             Electric Co., Ltd. F term (reference) 2H068 AA02 AA03 AA04 AA08 AA10                       BA58 BB07 BB08 BB59 CA06                       EA14 EA20 EA36 FA01 FA03                       FA07

Claims (18)

[Claims] 1. An electrophotographic photosensitive member having a surface protective layer, wherein the surface protective layer is at least one selected from a polymerizable unsaturated group and a group represented by the following formula (4) and the following formula (5). Silica particles bonded through an silyloxy group with an organic compound having, and a composition mainly containing a photopolymerization initiator, composed of a layer formed by curing, further on the surface of the surface protective layer, An electrophotographic photoreceptor comprising a chemisorption film via a siloxane bond, comprising at least one organosilane compound having a general structure represented by the following formulas (1) to (3).
(However, in the following formulas (1) to (3), R ₁ ,
R ₂ and R ₃ are organic functional groups, and X ₁ , X ₂ and X ₃ are leaving groups. Further, in the following formula (4), X is —NH—, —
It is selected from O- and -S-, and Y is selected from oxygen atom and sulfur atom. However, when X is -O-, Y is a sulfur atom. ) [Chemical 1] [Chemical 2] [Chemical 3] [Chemical 4] 2. In the formulas (1) to (3), R
_The electrophotographic photosensitive member according to claim 1, which is treated with an organosilane compound in which at least one of _{1 to} R ₃ is any of an octyl group, a dodecyl group, and an octadecyl group. 3. In the formulas (1) to (3), R
_The electrophotographic photosensitive member according to claim 1, which is treated with an organosilane compound in which two or more of _{1 to} R ₃ are any of a methyl group, an ethyl group, a propyl group, a butyl group, and a phenyl group. 4. In the formulas (1) to (3), R
₁To R_ThreeAt least one of the following formula (6) and the following formula
Fluorinated alkyl group or perfluoro represented by (7)
Organos that are organic functional groups containing polypolyether groups
The method according to claim 1, wherein the compound is treated with a orchid compound.
Electrophotographic photoreceptor. (In the following formula (6), n is 3 to 25
It is an integer. Also, in the following formula (7), R_fIs perfluo
R represents a polyether group, R_FourIs O, NH, or S
Is an atom or group of atoms, R ₅Is especially limited to carbon number
No alkylene chain is shown. ) [Chemical 5] 5. In the formulas (1) to (3), X
_{2. A} treatment with an organosilane compound in which at least one of _{1 to} X ₃ is an alkoxy group.
The electrophotographic photosensitive member according to any one of 1 to 4. 6. In the formulas (1) to (3), X
5. The electrophotographic photosensitive member according to claim 1, wherein at least one of _{1 to} X ₃ is treated with an organosilane compound which is an organic compound bonded via a nitrogen atom. 7. The electrophotographic photoreceptor according to claim 1, wherein the organosilane compound is heptadecafluorodecyltrimethoxysilane or a trialkoxysilane having a perfluoropolyether group. 8. The electrophotographic photosensitive member according to claim 1, wherein the organosilane compound is octadecyltriethoxysilane. 9. The electrophotographic photosensitive member according to claim 1, wherein the organosilane compound is any one of hexamethyldisilazane, diethoxydimethylsilane, dimethoxydiphenylsilane, or a mixture thereof. . 10. The electrophotographic photoreceptor according to claim 1, wherein the contact angle of water on the surface of the chemisorption film of the organosilane compound is 60 ° or more. 11. The electrophotographic photosensitive member according to claim 1, wherein the thickness of the chemically adsorbed film of the organosilane compound is 0.4 nm or more and 50 nm or less. 12. An ultraviolet curing surface treatment step of curing a surface protective layer coating material applied on a photoreceptor with ultraviolet rays having a predetermined wavelength or less, and a chemical adsorption layer treatment step of directly applying an organosilane compound on the photoreceptor. And a film-forming and drying step of drying the organosilane compound and chemically bonding the chemisorption layer onto the surface protection layer. 13. An ultraviolet curing surface treatment step of curing a surface protective layer coating material applied on a photoreceptor with ultraviolet rays having a predetermined wavelength or less, and an organosilane compound diluted to a predetermined concentration with a predetermined diluent solvent. The chemical adsorption layer treatment step of applying on the photoreceptor, and drying the dilution solvent,
And a film drying step of chemically bonding the chemical adsorption layer onto the surface protective layer. 14. The diluting solvent in the chemical adsorption layer treatment step is any one of water, an alcohol system, an alkane system, an aromatic system, an ether system, a fluorine system, or a mixed solvent thereof. 13. The method for producing an electrophotographic photosensitive member according to item 13. 15. The method for producing an electrophotographic photosensitive member according to claim 13, wherein the concentration of the organosilane compound solution in the chemical adsorption layer treatment step is 0.1% by weight or more and 10% by weight or less. 16. The film forming / drying step is performed at a temperature of 60 ° C. or higher and 120 ° C. or lower.
14. The method for producing an electrophotographic photosensitive member according to 2 or 13. 17. The method for producing an electrophotographic photosensitive member according to claim 12, wherein the ultraviolet rays in the ultraviolet curing surface treatment step have a wavelength of 310 nm or less. 18. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1 and a charging unit, an exposing unit, a developing unit, and a transferring unit.