JP3927930B2 - Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member, a process cartridge having an electrophotographic photosensitive member, and an electrophotographic apparatus.

  The electrophotographic photosensitive member is required to have sensitivity, electrical characteristics, optical characteristics, and the like according to the applied electrophotographic process. Since electrical or mechanical external forces such as charging, development with toner, transfer to paper, and cleaning are directly applied, durability against them is required.

  Specifically, the surface of the electrophotographic photosensitive member is abraded, scratched or abnormally generated by rubbing with a charging member, cleaning member, transfer member, or other auxiliary member, and the electrophotographic photosensitive member is charged under high humidity (primary Durability against deterioration of the surface of the electrophotographic photosensitive member due to adhesion of ozone or nitrogen oxide generated during charging is required.

  In recent years, an electrophotographic apparatus for charging an electrophotographic photosensitive member has been commercialized by discharging in a gap between a contact charging member to which a DC voltage or a voltage obtained by superimposing an alternating voltage on a DC voltage and the surface of the electrophotographic photosensitive member is discharged. Has been. However, such a contact charging method is less likely to generate an oxidizing gas such as ozone or nitrogen oxide than the conventional corona charging method, but molecules constituting the surface of the electrophotographic photosensitive member with high discharge energy. Since the molecular chain bond is broken, there is a problem that the deterioration becomes worse.

  Furthermore, there is also a problem of toner adhesion to the surface of the electrophotographic photoreceptor due to repeated development and cleaning, and for this problem, it is required to improve the cleaning property of the surface of the electrophotographic photoreceptor. .

  As a means for solving such a problem, Japanese Patent Application Laid-Open No. 05-053358 discloses providing a surface layer using a curable (crosslinkable) resin as a binder resin. However, in such a configuration, although the mechanical strength of the electrophotographic photosensitive member surface is improved, there is a tendency to be worsened with respect to the adverse effects caused by the adhesion of so-called charged products generated by ozone and nitrogen oxide generated during charging. There are tendencies to occur such as image blurring under high humidity, a decrease in toner transfer efficiency, and an increase in the coefficient of friction with a member in contact with the surface of the electrophotographic photosensitive member.

  Japanese Patent Application Laid-Open No. 06-083094 discloses that resin particles are contained in a surface layer made of a thermoplastic resin as a binder resin. However, with such a configuration, although problems associated with adhesion of charged products such as a decrease in transfer efficiency are improved, it is difficult to significantly improve the mechanical strength of the electrophotographic photosensitive member surface. Further, depending on the particle size and dispersion state, such resin particles cause light scattering in the photosensitive layer to deteriorate the image quality, or aggregates of resin particles become the starting point of scratches on the photosensitive layer. There is also a possibility that this will happen.

  It has also been proposed to reduce the coefficient of friction of the electrophotographic photoreceptor surface by adding silicone oil, stearate, etc. to the surface layer. By adding such a compound, the charge in the photosensitive layer can be reduced. This causes an adverse effect such as a change in image density due to an increase in residual potential, an image blur due to a decrease in electrical resistance, and a ghost image due to charges staying in the photosensitive layer. In addition, since such silicone oil has a high surface migration property and is localized only in the vicinity of the very surface in the photosensitive layer, the effect of adding this compound is reduced when the surface portion is worn away due to durability. . In particular, when a compound such as silicone oil is added to the surface layer, the adhesion between the surface layer and the layer below it may be reduced, and the surface layer may be peeled off.

  Further, in order to suppress the surface migration of a lubricant such as silicone oil, among the compounds having a small coefficient of friction, there is a method of dispersing particles having poor solubility in the surface layer. If it is not uniformly dispersed in the photosensitive layer, there will be adverse effects such as diffusion of the electrostatic latent image due to light scattering and generation of scratches originating from aggregates. Although the problem related to the dispersibility of these lubricant particles can be improved to some extent by adding a dispersant, the dispersant itself prevents the movement of charges in the photosensitive layer, or under high humidity. Since it behaves like an ionic conductive agent, the electrophotographic characteristics are hindered, and other problems such as a decrease in surface layer resistance, an increase in residual potential, and generation of a ghost image occur.

Thus, so far, without causing adverse effects such as image quality degradation due to light scattering, scratches due to aggregates, surface layer resistance decrease, residual potential increase, ghost image generation, surface layer adhesion decrease It has been difficult to improve the mechanical strength, electrical strength, friction reduction with various contact members, and transfer efficiency of the electrophotographic photosensitive member surface.
Japanese Patent Laid-Open No. 05-053358 Japanese Patent Laid-Open No. 06-083094

  Accordingly, the object of the present invention is to solve the above-mentioned problems, and in particular, without causing adverse effects such as image quality deterioration, has excellent lubricity, improved wear resistance, and has a long-life electrophotography having excellent electrophotographic characteristics. The object is to provide a photoreceptor.

  Another object of the present invention is to provide a process cartridge and an electrophotographic apparatus having such an electrophotographic photosensitive member.

  The above problems can be solved by including an acrylic polymer containing a polyfluoroolefin unit and an alkylene oxide unit in the surface layer of the electrophotographic photosensitive member, which reduces mechanical strength, electrical strength, and friction with various contact members. , Transfer efficiency can be improved.

。 That is, the present invention provides an electrophotographic photosensitive member having a photosensitive layer on a support,
The surface layer of the electrophotographic photosensitive member has an acrylic polymer of any one of the following (i) to (iv) whose number average molecular weight is in the range of 2000 to 20000 with respect to the total mass of the surface layer. An electrophotographic photosensitive member containing 1 to 20% by mass:
(I) a copolymer obtained only from a first acrylic ester monomer having a polyfluoroolefin unit and a second acrylic ester monomer having an alkylene oxide unit;
(Ii) Only from the first acrylic acid ester monomer, the second acrylic acid ester monomer, and any acrylic acid alkyl ester selected from the following structural formulas (3A-1) to (3A-24) The resulting copolymer;
(Iii) a polymer obtained only from an acrylate monomer having a polyfluoroolefin unit and an alkylene oxide unit;
(Iv) a copolymer obtained only from an acrylate monomer having a polyfluoroolefin unit and an alkylene oxide unit and any one of the acrylate alkyl esters selected from the following structural formulas (3A-1) to (3A-24): Polymer (provided that the polyfluoroolefin unit is a unit having 7 to 29 fluorine atoms per unit, the alkylene oxide unit is a unit having 2 to 4 carbon atoms per unit, and (The molar ratio of the polyfluoroolefin unit to the alkylene oxide unit (R ^F : R ^O ) is 0.1: 1 to 2: 1)

.

  The present invention also provides a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

  According to the present invention, it is possible to provide a long-life electrophotographic photoreceptor having excellent lubricity, improved wear resistance, and excellent electrophotographic characteristics without causing adverse effects such as image quality degradation. A process cartridge and an electrophotographic apparatus having such an electrophotographic photosensitive member can be provided.

  Even if the photosensitive layer of the electrophotographic photosensitive member of the present invention is a single layer type photosensitive layer containing a charge generating substance and a charge transporting substance in a single layer, the charge generating layer containing the charge generating substance and the charge transporting substance are included. A laminated photosensitive layer in which a charge transport layer containing a substance is laminated may be used, but a laminated photosensitive layer is preferable in terms of electrophotographic characteristics. Among the laminated photosensitive layers, a normal layer type photosensitive layer in which a charge generation layer and a charge transport layer are laminated in this order from the support side is more preferable.

  FIG. 1 shows an example of the layer structure of the electrophotographic photosensitive member of the present invention.

  In the electrophotographic photosensitive member having the layer structure shown in FIG. 1 (a), a charge generation layer 3 and a charge transport layer 2 are provided in this order on a support 4, and a polyfluoroolefin is further formed thereon as a surface layer. A layer 1 containing an acrylic polymer having a unit and an alkylene oxide unit and having a number average molecular weight of 2000 to 20000 (hereinafter also referred to as the acrylic polymer of the present invention) is provided. Further, as shown in FIGS. 1B and 1C, an intermediate layer (barrier layer, adhesive layer) 5 having a barrier function and an adhesive function between the support 4 and the charge generation layer 3 and interference fringe prevention. A conductive layer 6 for the purpose may be provided.

  In addition, the electrophotographic photosensitive member having the layer structure shown in FIG. 1 (d) is provided with a charge generation layer 3 on a support 4, and contains the acrylic polymer of the present invention as a surface layer thereon. Layer 1 is provided directly.

  In addition, the surface layer containing the acrylic polymer of the present invention may be a charge generation layer as long as the acrylic polymer of the present invention is contained in the surface layer of the electrophotographic photoreceptor regardless of the layer configuration. It is preferable that the layer is not in contact with. Further, the surface layer containing the acrylic polymer of the present invention is substantially free of charge generation material (specifically, the content of the charge generation material in the surface layer is based on the total mass of the surface layer). 0 to 5000 ppm (mass ratio) is preferable. If the surface layer is not in contact with the charge generation layer, and if the charge generation material is not substantially contained in the surface layer, the acrylic polymer of the present invention may contact (substantially) the charge generation material. This is because the injection of charges from the charge generation layer to the charge transport layer (from the charge generation material to the charge transport material) is not affected.

  As a support for the electrophotographic photosensitive member of the present invention, any support may be used as long as it has conductivity. For example, a support made of metal such as aluminum, an aluminum alloy, and stainless steel can be used. Moreover, the said metal support body and plastic support body which have the layer in which aluminum, an aluminum alloy, an indium oxide tin oxide alloy etc. were formed into a film by vacuum deposition can also be used. It is also possible to use a support in which conductive particles such as carbon black, tin oxide particles, titanium oxide particles and silver particles are impregnated with plastic or paper together with an appropriate binder resin, or a plastic having conductive binder resin. it can.

  As described above, a conductive layer may be provided on the support for the purpose of preventing interference fringes due to scattering of laser light or the like, and covering scratches on the support. The conductive layer can be formed by dispersing conductive particles such as carbon black and metal particles in a binder resin. The thickness of the conductive layer is preferably 5 to 40 μm, and more preferably 10 to 30 μm.

  Further, as described above, an intermediate layer having a barrier function or an adhesive function may be provided between the support or the conductive layer and the photosensitive layer (charge generation layer, charge transport layer). The intermediate layer is formed for the purpose of improving the adhesion of the photosensitive layer, improving the coating property, improving the charge injection property from the support, and protecting the photosensitive layer from electrical breakdown. The intermediate layer can be formed using materials such as casein, polyvinyl alcohol, ethyl cellulose, ethylene-acrylic acid copolymer, polyamide, modified polyamide, polyurethane, gelatin, and aluminum oxide. The thickness of the intermediate layer is preferably 5 μm or less, and more preferably 0.1 to 3 μm.

  Examples of the charge generating material used in the electrophotographic photoreceptor of the present invention include azo pigments such as monoazo, disazo, and trisazo, phthalocyanine pigments such as metal phthalocyanine and nonmetal phthalocyanine, indigo pigments such as indigo and thioindigo, Perylene pigments such as perylene acid anhydride and perylene imide, polycyclic quinone pigments such as anthraquinone and pyrenequinone, squarylium dyes, pyrylium salts and thiapyrylium salts, triphenylmethane dyes, selenium, selenium-tellurium, amorphous Examples thereof include inorganic substances such as silicon, quinacridone pigments, azulenium salt pigments, cyanine dyes, xanthene dyes, quinoneimine dyes, styryl dyes, cadmium sulfide, and zinc oxide. Among these, azo pigments and phthalocyanine pigments are preferable from the viewpoint of charge generation efficiency and charge injection properties, and metal phthalocyanine pigments are particularly preferable. These charge generating materials may be used alone or in combination of two or more.

  When the photosensitive layer is a laminated photosensitive layer, examples of the binder resin used for the charge generation layer include polycarbonate resin, polyester resin, polyarylate resin, butyral resin, polystyrene resin, polyvinyl acetal resin, diallyl phthalate resin, acrylic resin, Examples include methacrylic resin, vinyl acetate resin, phenol resin, silicone resin, polysulfone resin, styrene-butadiene copolymer resin, alkyd resin, epoxy resin, urea resin, vinyl chloride-vinyl acetate copolymer resin, and the like. These can be used alone, as a mixture or as a copolymer, or one or more thereof.

  The solvent used in the coating solution for the charge generation layer is selected from the solubility and dispersion stability of the binder resin and charge generation material used, and the organic solvents include alcohols, sulfoxides, ketones, ethers, esters, aliphatic halogens. Hydrocarbons and aromatic compounds.

  The charge generation layer can be formed by applying and drying a charge generation layer coating solution obtained by dispersing a charge generation material together with a binder resin and a solvent. Examples of the dispersion method include a method using a homogenizer, an ultrasonic wave, a ball mill, a sand mill, an attritor, a roll mill and the like. The ratio between the charge generation material and the binder resin is preferably in the range of 1: 0.3 to 1: 4.

  In applying the charge generation layer coating solution, for example, a coating method such as a dip coating method, a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, a blade coating method, or the like can be used.

  The thickness of the charge generation layer is preferably 5 μm or less, and more preferably 0.01 to 1 μm.

  In addition, various sensitizers, antioxidants, ultraviolet absorbers, plasticizers, and the like can be added to the charge generation layer as necessary.

  Examples of the charge transport material used in the electrophotographic photoreceptor of the present invention include triarylamine compounds, hydrazone compounds, styryl compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, triarylmethane compounds and the like.

  For example, the binder resin used for the charge transport layer that is not the surface layer of the electrophotographic photosensitive member, such as the charge transport layer 2 in FIGS. 1A, 1B, and 1C, is, for example, an acrylic resin. Styrene resin, polyester, polycarbonate resin, polyarylate, polysulfone, polyphenylene oxide, epoxy resin, polyurethane resin, alkyd resin, unsaturated resin, and the like. In particular, polymethyl methacrylate, polystyrene, styrene-acrylonitrile copolymer, polycarbonate resin, polyarylate resin, and diallyl phthalate resin are preferable.

  This charge transport layer can be formed by applying and drying a charge transport layer coating solution obtained by dissolving a charge transport material and a binder resin in a solvent. The ratio between the charge transport material and the binder resin is preferably in the range of 2: 1 to 1: 2 (mass ratio).

  Solvents used in the charge transport layer coating liquid include ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as toluene and xylene, and halogen atoms such as chlorobenzene, chloroform and carbon tetrachloride. Substituted hydrocarbons and the like are used.

  When applying the charge transport layer coating solution, for example, a coating method such as a dip coating method, a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, a blade coating method, or the like can be used. When drying after coating, the drying temperature is preferably in the range of 10 ° C to 200 ° C, more preferably in the range of 20 ° C to 150 ° C. The drying time is preferably in the range of 5 minutes to 5 hours, and particularly preferably in the range of 10 minutes to 2 hours. Drying may be air drying or static drying.

  The film thickness of the charge transport layer that is not the surface layer of the electrophotographic photosensitive member is preferably 5 to 40 μm, more preferably 7 to 30 μm.

  In addition, an antioxidant, an ultraviolet absorber, a plasticizer, and the like can be added to the charge transport layer as necessary.

  As described above, the surface layer of the electrophotographic photosensitive member provided on the photosensitive layer (for example, on the charge transport layer) or the surface layer of the electrophotographic photosensitive member provided directly on the charge generation layer is the acrylic polymer of the present invention. That is, it contains an acrylic polymer having a polyfluoroolefin unit and an alkylene oxide unit and a number average molecular weight of 2000 to 20000.

The content of the acrylic polymer of the present invention in the surface layer of the electrophotographic photoreceptor is 0.1 to 20% by mass , and more preferably 0.5 to 5% by mass with respect to the total mass of the surface layer.

The molar ratio of the acrylic polymer, polyfluoroolefin unit and ^{(R F)} and alkylene oxide units ^{(R O)} of the present invention ^(R F: R ^O) is 0.1: 1 to 2: is 1 , 0.2: 1 to 1: and more preferably 1.

  Examples of the method of incorporating the acrylic polymer of the present invention into the surface layer of the electrophotographic photosensitive member include a method of forming a surface layer using the surface layer coating solution containing the acrylic polymer of the present invention and an organic solvent. .

  As the organic solvent, an organic solvent having a proton acceptor parameter (δa) of 2 or more and a boiling point of 50 to 120 ° C. is preferable. By using such an organic solvent, the interaction between the layer below the surface layer and the acrylic polymer of the present invention in the surface layer is reduced, and without causing deterioration of image quality such as ghost, When the resin particles are contained in the layer, formation of the aggregates can be suppressed, so that generation of scratches due to the aggregates can be suppressed.

  Generally, the solubility parameter (δ) is used as an index representing the characteristics of the solvent. This index is divided into a dispersion solubility parameter, a dipole orientation parameter, a proton acceptor parameter, and a proton donor parameter according to various intermolecular interactions. Among these various parameters, the proton acceptor parameter (δa) is a particularly important parameter for incorporating the acrylic polymer of the present invention into the surface layer of the electrophotographic photosensitive member by the above method.

  Even if the organic medium is soluble in organic substances, the one having a small proton acceptor parameter (δa) has a great influence on other than the surface layer, and the acrylic polymer of the present invention should be uniformly present in the surface layer. Tend to be difficult.

  Hereinafter, preferred examples of the organic solvent having a proton acceptor parameter (δa) of 2 or more and a boiling point of 50 to 120 ° C. are shown.

  When applying the surface layer coating solution, for example, a coating method such as a dip coating method, a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, or a blade coating method can be used. When the surface layer of the electrophotographic photoreceptor is formed by the dip coating method, considering the influence on the layer below the surface layer, the proton acceptor parameter (δa) is 2 or more and the boiling point is 50 to 120 ° C. In addition, a non-aromatic organic solvent having a structure having no hetero atom other than oxygen is preferable.

  The acrylic polymer of the present invention may be a copolymer obtained from an acrylate monomer having a polyfluoroolefin unit and an acrylate monomer having an alkylene oxide unit, or may be a polyfluoroolefin unit and an alkylene oxide. It may be a polymer obtained from an acrylate monomer having both units.

  Thus, when the acrylic polymer of the present invention is obtained, even if resin particles are contained in the surface layer coating liquid, the dispersion stability of the resin particles is improved, and the coating liquid can be used over a long period of time. There is an advantage that

  The polyfluoroolefin unit is preferably a polyfluoroalkylene unit.

  The alkylene oxide unit is preferably an ethylene oxide unit or a propylene oxide unit, and more preferably an ethylene oxide unit. When the alkylene oxide unit is an ethylene oxide unit or a propylene oxide unit, the adhesion between the surface layer and the layer below it is further improved.

The polyfluoroolefin unit is a unit having 7 to 29 fluorine atoms per unit , and more preferably a unit having 9 to 21 fluorine atoms per unit. If the number of fluorine atoms per unit is less than 7, the effect of reducing the friction on the surface of the electrophotographic photosensitive member may be difficult to be exhibited. On the other hand, when the number of fluorine atoms per unit is more than 30, it may be difficult to uniformly contain the acrylic polymer in the surface layer. In addition, when the number of fluorine atoms per unit of the polyfluoroolefin unit is more than 30, the solubility in organic solvents having a boiling point of 50 to 120 ° C. is reduced when the proton acceptor parameter is 2 or more. And the acrylic polymer of this invention may be unevenly distributed in a surface layer, or the capability to disperse | distribute resin particles stably may fall.

The alkylene oxide unit is a unit having 2 to 4 carbon atoms per unit , and more preferably a unit having 2 carbon atoms per unit. That is, when the alkylene oxide unit is -O-R ¹¹ -(-R ¹¹ -is an alkylene group), the number of carbon atoms per R ¹¹ is preferably 2 to 4, particularly 2 More preferably. Specific examples include an ethylene oxide unit, a propylene oxide unit, an isopropylene oxide unit, and a butylene oxide unit. If the number of carbon atoms per unit is more than 4, it may be difficult to uniformly contain the acrylic polymer in the surface layer. Further, when the number of carbon atoms per unit is more than 4, the above-described proton acceptor parameter is 2 or more, and the solubility in an organic solvent having a boiling point of 50 to 120 ° C. is reduced. The acrylic polymer may be unevenly distributed in the surface layer, or the adhesion between the surface layer and the layer below the surface layer may be reduced.

  In the acrylate ester monomer having the alkylene oxide unit or in the acrylate ester monomer having both the polyfluoroolefin unit and the alkylene oxide unit, the number of alkylene oxide units is preferably 3 to 20, particularly More preferably, it is 5-10. When the number of alkylene oxide units is less than 3, the effect of having an alkylene oxide unit is weakened, and the above-described proton acceptor parameter is 2 or more, and an organic solvent having a boiling point of 50 to 120 ° C. The solubility may decrease, and the acrylic polymer of the present invention may be unevenly distributed in the surface layer, or the adhesion between the surface layer and the layer below the surface layer may be decreased. On the other hand, if the number of alkylene oxide units is more than 20, the mobility of charges in the surface layer decreases, leading to an increase in residual potential, or the surface resistance of the electrophotographic photoreceptor due to adhesion of charged products. If the surface layer contains conductive particles, the resistance of the surface layer is likely to decrease under high humidity, causing image blurring. There is a case.

  Below, the suitable example of the acrylate monomer which has a polyfluoro olefin unit is shown.

  Below, the suitable example of the acrylate monomer which has an alkylene oxide unit is shown.

(In said formula (AA-1)-(AA-24), n shows a positive integer, Preferably it is 3-20, More preferably, it is 5-10.)
Moreover, the suitable structure of the acrylate monomer which has both a polyfluoro olefin unit and an alkylene oxide unit is shown by a following formula (PAA-A), (PAA-B), or (PAA-C).

(In the above formulas (PAA-A), (PAA-B), and (PAA-C), R 2 ^O represents an alkylene oxide unit, R ^F represents a polyfluoroolefin unit, and R ²¹ and R ²² are each independently N represents a positive integer, preferably 3 to 20, more preferably 5 to 10. The number of carbon atoms in R 2 ^O is preferably 2 to 4. Yes, more preferably 2. The number of fluorine atoms in R ^F is preferably 7 to 29, more preferably 9 to 21.)
Below, the suitable example of the acrylate monomer which has both a polyfluoro olefin unit and an alkylene oxide unit is shown.

Further, when the acrylic polymer of the present invention is obtained, the acrylic acid ester monomer having the polyfluoroolefin unit and the acrylic acid ester monomer having the alkylene oxide unit, or both the polyfluoroolefin unit and the alkylene oxide unit are included. In addition to the acrylate monomer, for example, in order to improve the compatibility between the acrylic polymer of the present invention and the binder resin of the surface layer, the following structural formulas (3A-1) to (3A-24) are selected. You may use the acrylic acid alkylester shown by either . Further, the alkyl group of the acrylic acid alkyl ester may have a hydroxy group as a substituent. Acrylic polymer of the present invention obtained by using the acrylic acid alkyl ester, can be more markedly suppressed the resistance decrease under high humidity, even electrophotographic system attachment often of charge products, electronic Even when conductive particles are included in the surface layer of the photographic photoreceptor, image blurring is not caused.

  The surface layer of the electrophotographic photosensitive member of the present invention has a binder resin such as polyarylate resin, polycarbonate resin, polyester resin, polystyrene resin, polyacrylate resin, phenol resin, melamine resin, epoxy resin. A curable resin such as a resin, an isocyanate resin, an acrylic resin, or a siloxane resin can be used. Among these, image blur due to adhesion of charged products and abnormal noise due to rubbing between the electrophotographic photosensitive member and the contact member are prevented, and the mechanical strength and electrical strength of the electrophotographic photosensitive member are remarkably improved. A curable resin is preferable in that it can be made to occur.

  By including the acrylic polymer of the present invention and a curable resin in the surface layer of the electrophotographic photosensitive member, and further including resin particles, image quality deterioration due to light scattering, generation of scratches due to aggregates, Mechanical effects on the surface of the electrophotographic photoreceptor without causing adverse effects such as lowering resistance, increasing residual potential, generating ghost images, and lowering the adhesion of the surface layer, and without causing adverse effects due to the inclusion of resin particles It is possible to achieve higher levels of strength, electrical strength, friction reduction with various contact members, and improvement of transfer efficiency.

  Of the curable resins, a curable resin obtained from a monomer having a hydroxy group before curing is more preferable.

  In the present invention, the surface layer may contain conductive particles or a charge transport material.

  Examples of the conductive particles include zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, graphite, carbon black, tin oxide doped with indium, tin oxide doped with antimony, and zirconium oxide. Is mentioned. These conductive particles may be used alone or in combination of two or more. When using 2 or more types, it may be a solid solution state or a fused state.

  The content of the conductive particles in the surface layer of the electrophotographic photosensitive member is preferably 20 to 80% by mass, and more preferably 30 to 60% by mass with respect to the total mass of the surface layer. Moreover, 10-500 mass% is preferable with respect to the acrylic polymer of this invention contained in a surface layer, and 20-50 mass% is more preferable especially.

  Examples of the charge transport material include triarylamine compounds, hydrazone compounds, styryl compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, and triarylmethane compounds as described above. These charge transport materials may be used alone or in combination of two or more.

  In addition, when a curable resin is used as the binder resin for the surface layer, and further, when the resin particles are included in the surface layer, the charge transport material contained in the surface layer is a hydroxyl group before curing, among the charge transport materials. Charge transport materials having the following are preferred:

  The content of the charge transport material in the surface layer of the electrophotographic photoreceptor is preferably 10 to 80% by mass, more preferably 30 to 60% by mass, based on the total mass of the surface layer. Moreover, 5-500 mass% is preferable with respect to the acrylic polymer of this invention contained in a surface layer, and 15-200 mass% is especially more preferable. Moreover, 4-600 mass% is preferable with respect to curable resin contained in a surface layer, and 10-250 mass% is more preferable especially.

  Below, the suitable example of the charge transport material which has a hydroxyl group is shown.

  Since the charge transport materials shown in Compound Examples C62 to C65 have a hydroxymethyl group at the ortho position of the phenolic hydroxyl group, the thermosetting reaction can proceed only with this compound. When such a compound is used as a charge transport material, it is possible to maintain a certain degree of surface hardness without using a curable resin as a binder resin, and by using a curable resin as a binder resin. It becomes possible to obtain a stronger surface layer. Furthermore, a curable surface layer having charge transportability and a desired surface hardness can be formed by this curable charge transport material without using a binder resin component.

  Further, as described above, the surface layer of the electrophotographic photosensitive member of the present invention may contain resin particles. By incorporating resin particles in the surface layer of the electrophotographic photosensitive member, the coefficient of friction on the surface of the electrophotographic photosensitive member can be reduced. As described above, the combined use of the resin particles, the acrylic polymer of the present invention, and the curable resin in the surface layer of the electrophotographic photosensitive member does not cause the adverse effect of image quality deterioration due to light scattering.

  Examples of the resin particles include polyethylene, polypropylene, polymethylene oxide, polystyrene, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polydichlorodifluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetra Examples thereof include particles such as a fluoroethylene-hexafluoropropylene copolymer, a tetrafluoroethylene-ethylene copolymer, and a tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer. These resin particles may be used alone or in combination of two or more. Among these resin particles, fluorine atom-containing resin particles and silicon atom-containing resin particles are preferable, and in particular, fluorine atom-containing resin particles are more preferable in that the transfer efficiency of the toner can be further improved.

  The particle diameter of the resin particles is preferably 0.01 to 10 μm, more preferably 0.05 to 2.0 μm, in that light scattering and aggregate formation can be suppressed. Furthermore, it is still more preferable that it is 0.1-0.8 micrometer.

  If the polyfluoroolefin unit is a unit having 7 to 29 fluorine atoms per unit, the particle size of the resin particles is maintained while maintaining the effect of reducing the friction coefficient of the electrophotographic photosensitive member surface at a high level. Can be easily set within the preferred range.

  The content of the resin particles in the surface layer of the electrophotographic photosensitive member is preferably 0.5 to 50% by mass, more preferably 2 to 25% by mass with respect to the total mass of the surface layer. Moreover, 1000-5000 mass% is preferable with respect to the acrylic polymer of this invention contained in a surface layer, and 2000-3000 mass% is more preferable especially. Moreover, 1-100 mass% is preferable with respect to curable resin contained in a surface layer, and 3-50 mass% is more preferable especially.

  Further, the surface layer of the electrophotographic photoreceptor of the present invention contains an antioxidant for the purpose of preventing deterioration of the surface layer due to adhesion of active substances such as charged products (such as ozone and nitrogen oxides). May be.

  FIG. 2 shows a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.

  In FIG. 2, reference numeral 11 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is rotationally driven around a shaft 12 in the direction of an arrow at a predetermined peripheral speed. In the rotation process, the electrophotographic photosensitive member 11 is charged uniformly (positive or negative) by a charging means (primary charging means) 13 on its peripheral surface, and then exposed to exposure means such as slit exposure or laser beam scanning exposure. Exposure light (image exposure light) 14 output from (not shown) is received. In this way, electrostatic latent images corresponding to target image information are sequentially formed on the peripheral surface of the electrophotographic photosensitive member 11.

  The formed electrostatic latent image is then developed with toner by the developing means 15 and taken out from a paper feeding unit (not shown) between the electrophotographic photosensitive member 11 and the transfer means 16 in synchronization with the rotation of the electrophotographic photosensitive member 11. The toner image formed and supported on the peripheral surface of the electrophotographic photosensitive member 11 is sequentially transferred by the transfer means 16 onto the transfer material 17 such as paper fed in this manner.

  The transfer material 17 that has received the transfer of the toner image is separated from the peripheral surface of the electrophotographic photosensitive member, introduced into the fixing means 18, and subjected to image fixing, thereby being printed out as an image formed product (print, copy). Is done.

  The peripheral surface of the electrophotographic photosensitive member 11 after the image transfer is cleaned by removing the transfer residual toner by the cleaning unit 19, and is further neutralized by the pre-exposure light 20 from the pre-exposure unit (not shown). After that, it is repeatedly used for image formation. When the charging unit 13 is a contact charging unit using a charging roller or the like, pre-exposure is not always necessary.

  In the present invention, among the above-described components such as the electrophotographic photosensitive member 11, the charging unit 13, the developing unit 15, and the cleaning unit 19, a plurality of components are housed in a container and integrally combined as a process cartridge. The process cartridge may be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. For example, at least one of the charging unit 13, the developing unit 15, and the cleaning unit 19 is integrally supported together with the electrophotographic photosensitive member 11 to form a cartridge, and is detachable from the apparatus main body using a guide unit 22 such as a rail of the apparatus main body. A simple process cartridge 21.

  Further, when the electrophotographic apparatus is a copying machine or a printer, the exposure light 14 is reflected light or transmitted light from the original, or the original is read by a sensor and converted into a signal, and a laser beam performed in accordance with this signal. Light emitted by scanning, driving an LED array or driving a liquid crystal shutter array.

  The electrophotographic photoreceptor of the present invention can be used not only for copying machines and laser beam printers but also for a wide range of electrophotographic applications such as CRT printers, LED printers, FAX, liquid crystal printers, and laser plate making. .

(Example)
Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to these. In the examples, “part” means “part by mass”.

(Acrylic polymer examples 1 to 11)
The acrylic polymer having the weight average molecular weight (Mn) shown in the table below was obtained from the acrylate monomer shown in the table below.

In Table 2, PPA means an acrylate ester monomer having a polyfluoroolefin unit and an alkylene oxide unit, PA means an acrylate ester monomer having a polyfluoroolefin unit, and AA is an acrylate ester having an alkylene oxide unit. It means a monomer, and 3A means any acrylic acid alkyl ester selected from the structural formulas (3A-1) to (3A-24) .

  The weight average molecular weight (Mn) is a value obtained by measurement by gel permission column chromatography (GPC), and is a number average molecular weight in terms of polystyrene.

Example 1
A 5 mass% methanol solution of polyamide resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) is immersed on an aluminum cylinder (JIS-A3003, aluminum alloy) having a length of 260.5 mm and a diameter of 30 mm as a support. It was applied by a coating method to provide an intermediate layer having a thickness of 0.5 μm.

  Next, 3 parts of a crystalline hydroxygallium phthalocyanine crystal having the strongest peak at 28.1 ° with a Bragg angle 2θ ± 0.2 in CuKα characteristic X-ray diffraction as a charge generating substance, and a polyvinyl butyral resin as a binder resin (Trade name: BX-1, manufactured by Sekisui Chemical Co., Ltd.) was added to 100 parts of cyclohexanone and dispersed for 1 hour in a sand mill containing glass beads having a diameter of 1 mm. This dispersion is diluted with 100 parts of methyl ethyl ketone to prepare a coating solution for a charge generation layer, dip-coated on the intermediate layer, and dried at 90 ° C. for 10 minutes to generate a charge of 0.15 μm thickness. A layer was formed.

  Next, 8.5 parts of a charge transport material having a structure represented by the following formula:

10 parts of a bisphenol Z type polycarbonate resin having a repeating structural unit represented by the following formula (viscosity average molecular weight: 20000, trade name: Z-200, manufactured by Mitsubishi Gas Chemical Co., Ltd.),

In addition, 1.0 part of acrylic polymer example (1) was dissolved in 50 parts of monochlorobenzene and 30 parts of tetrahydrofuran. This solution was dip coated on the charge generation layer and dried with hot air at 110 ° C. for 1 hour to form a charge transport layer having a thickness of 17 μm.

  Thus, an electrophotographic photosensitive member having a charge transport layer as a surface layer was produced.

(Example 2)
In Example 1, the bisphenol Z-type polycarbonate resin in the charge transport layer is a polycarbonate resin having a repeating structural unit represented by the following formula (viscosity average molecular weight: 38000).

An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the above was changed.

(Example 3)
In Example 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge generation layer and the charge transport layer as the surface layer were formed as follows.

  That is, as a charge generation material, crystalline oxytitanium phthalocyanine having strong peaks at 9.0 °, 14.2 °, 23.9 °, and 27.1 ° with a Bragg angle 2θ ± 0.2 in CuKα characteristic X-ray diffraction 4 parts and 2 parts of polyvinyl butyral resin (trade name: BX-1, manufactured by Sekisui Chemical Co., Ltd.) as a binder resin are added to 80 parts of cyclohexanone and dispersed in a sand mill containing glass beads having a diameter of 1 mm for 4 hours. Then, a charge generation layer coating solution was prepared, dip-coated on the intermediate layer, and dried at 105 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.22 μm.

  Next, 8.5 parts of a charge transport material having a structure represented by the following formula:

10 parts of a polyarylate resin having a repeating structural unit represented by the following formula (viscosity average molecular weight: 89000),

In addition, 1.0 part of acrylic polymer example (1) was dissolved in 50 parts of monochlorobenzene and 30 parts of tetrahydrofuran. This solution was dip coated on the charge generation layer and dried with hot air at 110 ° C. for 1 hour to form a charge transport layer having a thickness of 17 μm.

Example 4
In Example 1, a bisazo pigment having a structure represented by the following formula for hydroxygallium phthalocyanine in the charge generation layer

An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the above was changed.

(Examples 5-7)
In Example 1, an electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the acrylic polymer example (1) in the charge transport layer was changed to acrylic polymer examples (2), (3), and (4), respectively. Produced.

(Comparative Example 1)
In Example 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the acrylic polymer was not added to the charge transport layer.

(Comparative Examples 2 and 3)
In Example 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the acrylic polymer example (1) in the charge transport layer was changed to acrylic polymer examples (9) and (10), respectively.

(Evaluation 1)
Regarding the electrophotographic photosensitive members produced in Examples 1 to 7 and Comparative Examples 1 to 3, Canon Inc. laser printer LBP-NX (contact charging means employing a charging roller (applied voltage is an AC voltage superimposed on a DC voltage) 7000 in two environments of temperature 5 ° C./humidity 15 RH% (LL environment) and temperature 32.5 ° C./humidity 80 RH% (HH environment). The durability test of the sheet was performed.

Evaluation items are
(1-1) Image quality after endurance in LL environment,
(1-2) Potential fluctuation in the LL environment (difference in the bright part potential after the initial and continuous 50 sheets output),
(1-3) Image quality after endurance in an HH environment
(1-4) The contact angle of water on the surface of the electrophotographic photoreceptor after durability in an HH environment.

  The evaluation results are shown in Table 3.

  From the evaluation results shown in Table 3, the electrophotographic photoreceptor having the charge transport layer containing the acrylic polymer of the present invention as the surface layer has stable and good image quality after the durability test, and the potential fluctuation is large. In addition, it can be seen that the surface contact angle with water is maintained at a high level.

  Among these, the potential fluctuation was smaller when the charge generation material was a phthalocyanine pigment than when the charge generation material was an azo pigment, but this is said to be a bulk type for an azo pigment whose charge generation is said to be an interface type. It may be more susceptible to the acrylic polymer of the present invention contained in the charge transport layer than the phthalocyanine pigment.

  Among the acrylic polymers, in the case of an electrophotographic photosensitive member having a charge transport layer containing an acrylic polymer having only an alkylene oxide unit without having a polyfluoroolefin unit, not only the potential fluctuation is large, but also in an HH environment. The contact angle with water on the surface after durability was drastically decreased, and image blurring occurred.

  In contrast, in the case of an electrophotographic photosensitive member having a charge transport layer containing an acrylic polymer having only an alkylene oxide unit and not an alkylene oxide unit, the contact angle with water on the surface, which was high before image output, was high. At the very initial stage of the durability test, it became equivalent to the electrophotographic photosensitive member without addition of acrylic polymer (Comparative Example 1). This is presumably because the acrylic polymer was unevenly distributed on the surface side of the surface layer (charge transport layer) because there was no anchor effect due to the alkylene oxide unit or alkylene unit.

(Example 8)
In Example 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer as the surface layer was formed as follows.

  That is, 8.5 parts of a charge transport material having a structure represented by the following formula:

10 parts of a bisphenol Z-type polycarbonate resin having a repeating structural unit represented by the following formula (viscosity average molecular weight: 40000, trade name: Z-400, manufactured by Mitsubishi Gas Chemical Co., Ltd.),

In addition, 1.0 part of acrylic polymer example (1) was dissolved in 40 parts of monochlorobenzene and 40 parts of tetrahydrofuran. To this solution, 3.6 parts of polytetrafluoroethylene (PTFE) particles (trade name: L-2, manufactured by Daikin Chemical Industries, Ltd.) are added and stirred with a homogenizer until the solution is uniform. PTFE particles were dispersed at a pressure of 58.9 MPa (600 kgf / cm ² ) using a fluidizer (manufactured by Tsukishima Kikai Co., Ltd.). The volume average particle diameter of the PTFE particles after dispersion was 0.21 μm.

  This dispersion was dip coated on the charge generation layer and dried in hot air at 110 ° C. for 1 hour to form a charge transport layer having a thickness of 17 μm.

(Examples 9 to 11)
In Example 8, an electrophotographic photosensitive member was prepared in the same manner as in Example 8, except that the acrylic polymer example (1) in the charge transport layer was changed to acrylic polymer examples (5), (6), and (7), respectively. Produced.

  The volume average particle diameters of the PTFE particles after dispersion were 0.25 μm, 0.20 μm, and 0.32 μm, respectively.

(Example 12)
In Example 8, an electrophotographic photosensitive member was produced in the same manner as in Example 8, except that the PTFE particles in the charge transport layer were changed to silicone resin particles (trade name: Tospearl 103, manufactured by Toshiba Silicone Co., Ltd.). .

  The volume average particle size of the dispersed silicone resin particles was 0.37 μm.

(Comparative Example 4)
In Example 12, an electrophotographic photosensitive member was produced in the same manner as in Example 12 except that the acrylic polymer was not added to the charge transport layer.

  The volume average particle size of the silicone resin particles after dispersion could not be measured.

(Comparative Example 5)
In Example 12, the acrylic polymer example (1) in the charge transport layer was changed to an isooctylphenyl polyethoxyethanol surfactant (trade name: TRITON X-102, manufactured by Rohm and Haas (Philadelphia, Pennsylvania)). An electrophotographic photosensitive member was produced in the same manner as in Example 12 except for the change.

  The volume average particle size of the dispersed silicone resin particles was 1.55 μm.

(Comparative Example 6)
In Example 12, an electrophotographic photosensitive member was produced in the same manner as in Example 12 except that the acrylic polymer example (1) in the charge transport layer was changed to the acrylic polymer example (8).

  The volume average particle size of the dispersed silicone resin particles was 2.32 μm.

(Comparative Example 7)
In Example 8, the acrylic polymer example (1) in the charge transport layer is an acrylic polymer having a number average molecular weight of less than 2000 (number average molecular weight: 930), trade name: DS-406, manufactured by Daikin Chemical Industries, Ltd. The electrophotographic photosensitive member was produced in the same manner as in Example 8 except that the above was changed.

  The volume average particle diameter of the PTFE particles after dispersion was 0.89 μm.

  In the present invention, the volume average particle diameter of the particles was measured using a particle size distribution measuring apparatus manufactured by Horiba, Ltd.

(Evaluation 2)
Regarding the electrophotographic photoreceptors produced in Examples 8 to 12 and Comparative Examples 4 to 7, as in Evaluation 1, laser printer LBP-NX manufactured by Canon Inc. (contact charging means employing a charging roller (applied voltage is DC) And a cleaning means employing a urethane rubber cleaning blade) and a temperature of 5 ° C./humidity of 15 RH% (LL environment) and a temperature of 32.5 ° C. / A durability test of 7000 sheets was performed in two environments with a humidity of 80 RH% (HH environment).

Evaluation items are
(2-1) Image quality after endurance in the LL environment,
(2-2) Reproducibility of fine lines of images after endurance in LL environment,
(2-3) Potential fluctuation in the LL environment (difference in bright part potential after initial and continuous 50 sheets output),
(2-4) Contact angle of water on the surface of the electrophotographic photosensitive member after durability in an HH environment,
(2-5) Abrasion amount of electrophotographic photosensitive member after continuous output of 1000 sheets in HH environment.

  The electrophotographic photosensitive member produced in Comparative Example 1 was also evaluated with the same items.

  The evaluation results are shown in Table 4.

  From the evaluation results shown in Table 4, the electrophotographic photosensitive member containing both the resin particles and the acrylic polymer of the present invention in the charge transport layer as the surface layer has a small amount of wear in the durability test, and the potential fluctuation is not large. It can be seen that the reproducibility of the fine line is also good and the contact angle of the surface with water is maintained at a high level.

  On the other hand, the electrophotographic photosensitive member (Comparative Examples 4 to 7) in which the resin particles are contained in the charge transport layer which is the surface layer without containing the acrylic polymer of the present invention is inferior in the reproducibility of the fine lines. However, this is presumed as follows from the dispersed particle diameter of the resin particles in the charge transport layer coating solution. That is, in the electrophotographic photoreceptors of Comparative Examples 4 to 7, the resin particles are considerably aggregated in the charge transport layer, whereby the exposure light is scattered and the electrostatic latent image is disturbed, so that the reproducibility of fine lines is inferior. It is thought that it became a result.

  Further, the peripheral scratches on the post-endurance images in Comparative Examples 4 to 6 are due to the peripheral scratches on the surface of the electrophotographic photosensitive member of Comparative Examples 4 to 6, and most of the starting points of the peripheral scratches are the surface of the electrophotographic photosensitive member. It was a minute protrusion present in As a result of analyzing these minute protrusions, all were aggregates of resin particles.

(Example 13)
In the same manner as in Comparative Example 1, an intermediate layer, a charge generation layer, and a charge transport layer were formed on the support.

  Next, 5.0 parts of a charge transport material having a structure represented by the following formula:

10 parts of a bisphenol Z-type polycarbonate resin having a repeating structural unit represented by the following formula (viscosity average molecular weight: 80000, trade name: Z-800, manufactured by Mitsubishi Gas Chemical Co., Ltd.),

In addition, 3.0 parts of acrylic polymer example (1) was dissolved in 100 parts of monochlorobenzene and 300 parts of tetrahydrofuran. This solution was spray-coated on the charge transport layer and dried with hot air at 120 ° C. for 1 hour to form a second charge transport layer having a thickness of 3 μm.

  In this manner, an electrophotographic photoreceptor having the second charge transport layer as a surface layer was produced.

(Example 14)
In Example 13, a polyarylate resin having a repeating structural unit represented by the following formula (viscosity average molecular weight: 12000) as a bisphenol Z-type polycarbonate resin in the second charge transport layer

An electrophotographic photosensitive member was produced in the same manner as in Example 13 except that the above was changed.

(Example 15)
In Example 13, an electrophotographic photosensitive member was produced in the same manner as in Example 13 except that the acrylic polymer example (1) in the second charge transport layer was changed to the acrylic polymer example (7).

(Example 16)
In Example 14, an electrophotographic photosensitive member was produced in the same manner as in Example 14 except that the acrylic polymer example (1) in the second charge transport layer was changed to the acrylic polymer example (5).

(Example 17)
In Example 13, an electrophotographic photosensitive member was produced in the same manner as in Example 13 except that the second charge transport layer as the surface layer was formed as follows.

  That is, 5.0 parts of a charge transport material having a structure represented by the following formula:

10 parts of a bisphenol Z-type polycarbonate resin having a repeating structural unit represented by the following formula (viscosity average molecular weight: 80000, trade name: Z-800, manufactured by Mitsubishi Gas Chemical Co., Ltd.),

In addition, 3.0 parts of acrylic polymer example (1) was dissolved in 100 parts of monochlorobenzene and 100 parts of tetrahydrofuran. To this solution, 3.6 parts of polytetrafluoroethylene (PTFE) particles (trade name: L-2, manufactured by Daikin Chemical Industries, Ltd.) are added and stirred with a homogenizer until the solution is uniform. PTFE particles were dispersed at a pressure of 58.9 MPa (600 kgf / cm ² ) using a fluidizer (manufactured by Tsukishima Kikai Co., Ltd.). The volume average particle diameter of the PTFE particles after dispersion was 0.22 μm.

  This dispersion was spray-coated on the charge transport layer and dried with hot air at 120 ° C. for 1 hour to form a second charge transport layer having a thickness of 3 μm.

(Example 18)
In Example 17, the bisphenol Z-type polycarbonate resin in the second charge transport layer is a polyarylate resin having a repeating structural unit represented by the following formula (viscosity average molecular weight: 12000)

An electrophotographic photosensitive member was produced in the same manner as in Example 17 except that:

  The volume average particle size of the PTFE particles after dispersion was 0.21 μm.

Example 19
In Example 17, the electrophotographic photosensitive member was prepared in the same manner as in Example 17 except that the PTFE particles in the second charge transport layer were changed to silicone resin particles (trade name: Tospearl 103, manufactured by Toshiba Silicone Co., Ltd.). Produced.

  The volume average particle size of the dispersed silicone resin particles was 0.35 μm.

(Example 20)
In Example 18, the electrophotographic photosensitive member was prepared in the same manner as in Example 18 except that the PTFE particles in the second charge transport layer were changed to silicone resin particles (trade name: Tospearl 103, manufactured by Toshiba Silicone Co., Ltd.). Produced.

  The volume average particle size of the dispersed silicone resin particles was 0.36 μm.

(Comparative Example 8)
In Example 13, an electrophotographic photosensitive member was produced in the same manner as in Example 13 except that the second charge transport layer as the surface layer was formed as follows.

  That is, 5.0 parts of a charge transport material having a structure represented by the following formula:

And 10 parts of a bisphenol A type polycarbonate resin (viscosity average molecular weight: 20000) having a repeating structural unit represented by the following formula:

Dissolved in 100 parts of monochlorobenzene and 300 parts of tetrahydrofuran. This solution was spray-coated on the charge transport layer and dried with hot air at 100 ° C. for 1 hour to form a second charge transport layer having a thickness of 2 μm.

(Comparative Example 9)
In Example 13, an electrophotographic photosensitive member was produced in the same manner as in Example 13 except that the second charge transport layer as the surface layer was formed as follows.

  That is, 5.0 parts of a charge transport material having a structure represented by the following formula:

10 parts of a bisphenol A type polycarbonate resin (viscosity average molecular weight: 20000) having a repeating structural unit represented by the following formula,

And 2.0 parts of acrylic polymer examples (10) were dissolved in 100 parts of monochlorobenzene and 300 parts of tetrahydrofuran. This solution was dip coated on the charge transport layer and dried in hot air at 120 ° C. for 1 hour to form a second charge transport layer having a thickness of 2 μm.

(Comparative Example 10)
In Example 13, an electrophotographic photosensitive member was produced in the same manner as in Example 13 except that the second charge transport layer as the surface layer was formed as follows.

  That is, 5.0 parts of a charge transport material having a structure represented by the following formula:

And 10 parts of a bisphenol Z-type polycarbonate resin (viscosity average molecular weight: 2000, trade name: Z-200, manufactured by Mitsubishi Gas Chemical Co., Ltd.) having a repeating structural unit represented by the following formula,

Dissolved in 100 parts of monochlorobenzene and 100 parts of tetrahydrofuran. To this solution, 3.6 parts of silicone resin particles (trade name: Tospearl 103, manufactured by Toshiba Silicone Co., Ltd.) are added, stirred with a homogenizer until the solution is uniform, and further microfluidizer (Tsukishima Machine Co., Ltd.). The silicone resin particles were dispersed at a pressure of 58.9 MPa (600 kgf / cm ² ). The volume average particle size of the dispersed silicone resin particles could not be measured.

  This dispersion was spray-coated on the charge transport layer and dried with hot air at 120 ° C. for 1 hour to form a second charge transport layer having a thickness of 4 μm.

(Evaluation 3)
Regarding the electrophotographic photoreceptors prepared in Examples 13 to 20 and Comparative Examples 8 to 10, as in Evaluation 1, a laser printer LBP-NX manufactured by Canon Inc. (contact charging means employing a charging roller (applied voltage is DC) And a cleaning means employing a urethane rubber cleaning blade) and a temperature of 5 ° C./humidity of 15 RH% (LL environment) and a temperature of 32.5 ° C. / Durability tests were conducted in two environments with a humidity of 80 RH% (HH environment). However, the durable number was changed from 7000 to 8000.

Evaluation items are
(3-1) Image quality after endurance in the LL environment,
(3-2) Reproducibility of fine lines of images after endurance in LL environment,
(3-3) Potential fluctuation in the LL environment (difference in bright part potential after initial and continuous 50 sheets output),
(3-4) Contact angle of water on the surface of the electrophotographic photosensitive member after durability in an HH environment,
(3-5) The amount of wear of the electrophotographic photosensitive member after continuous output of 1000 sheets in an HH environment.

  The evaluation results are shown in Table 5.

  From the evaluation results shown in Table 5, the electrophotographic photosensitive member having the second charge transport layer containing the acrylic polymer of the present invention as the surface layer has stable and good image quality after the durability test, and potential fluctuations It is recognized that the contact angle with water on the surface is maintained at a high level.

  In the case of an electrophotographic photoreceptor having a second charge transport layer containing an acrylic polymer having no alkylene oxide unit and only a polyfluoroolefin unit, the contact angle with water on the surface, which was high before image output, is durable. At the very initial stage of the test, it became equivalent to an electrophotographic photosensitive member without addition of an acrylic polymer (Comparative Example 8). This is presumably because the acrylic polymer was unevenly distributed on the surface side of the surface layer (second charge transport layer) because there was no anchor effect due to alkylene oxide units or alkylene units.

  In addition, the electrophotographic photosensitive member containing both the resin particles and the acrylic polymer of the present invention in the second charge transport layer, which is the surface layer, has a small wear amount in the durability test, does not have a large potential fluctuation, and the reproducibility of the fine line It is recognized that the contact angle with water on the surface is maintained at a high level.

  Focusing on the potential fluctuation, it can be seen that the electrophotographic photoreceptors of Examples 13 to 20 are smaller than the electrophotographic photoreceptors of Examples 1 to 12, but this is an electron containing the acrylic polymer of the present invention. Since the surface layer (second charge transport layer) of the photographic photoreceptor is not in contact with the charge generation layer, injection of charges from the charge generation layer to the charge transport layer (from the charge generation material to the charge transport material) is prevented. It is thought that there was not.

  The electrophotographic photosensitive member (Comparative Example 10) in which the second charge transporting layer, which is the surface layer, did not contain the acrylic polymer of the present invention but contained resin particles resulted in inferior reproducibility of fine lines. This is inferred from the dispersed particle diameter of the resin particles in the second charge transport layer coating solution as follows. That is, in the electrophotographic photosensitive member of Comparative Example 10, the resin particles are considerably aggregated in the second charge transport layer, whereby the exposure light is scattered and the electrostatic latent image is disturbed, so that the reproducibility of fine lines is inferior. It is thought that it became a result.

  In addition, the peripheral scratches on the post-endurance image in Comparative Example 10 are due to the peripheral scratches on the surface of the electrophotographic photosensitive member of Comparative Example 10, and many of the starting points of the peripheral scratches are microscopic existing on the surface of the electrophotographic photosensitive member. It was a rough projection. As a result of analyzing these minute protrusions, all were aggregates of resin particles.

(Example 21)
In the same manner as in Comparative Example 1, an intermediate layer, a charge generation layer, and a charge transport layer were formed on the support.

  Next, a siloxane compound having a repeating structural unit represented by the following formula

50 parts of antimony-doped conductive tin oxide particles (trade name: T-1, manufactured by Mitsubishi Materials Corp., average particle size: 0.03 μm) surface-treated with 1 to 150 parts of acetone And dispersed for 72 hours in a sand mill. In this dispersion, 1.5 parts of the acrylic polymer example (1) and 15 parts of a resol type phenol resin (trade name: PL-4852, manufactured by Gunei Chemical Industry Co., Ltd.) were dissolved. This solution was spray-coated on the charge transport layer and heated at 155 ° C. for 1 hour to be cured to form a protective layer (cured resin layer) having a thickness of 3 μm.

  In this way, an electrophotographic photoreceptor having a protective layer (cured resin layer) as a surface layer was produced.

(Example 22)
In Example 21, the phenol resin in the protective layer (cured resin layer) was changed to an amino resin (trade name: Cymel C-370, manufactured by Mitsui Cytec Co., Ltd.), and the acrylic polymer example (1) was changed to an acrylic polymer example ( An electrophotographic photosensitive member was produced in the same manner as in Example 21 except for changing to 2).

(Example 23)
In Example 23, an electrophotographic photosensitive member was produced in the same manner as in Example 23 except that the protective layer (cured resin layer) as the surface layer was formed as follows.

  That is, 7 parts of a charge transport material having a structure represented by the above formula (C-9), 12 parts of a resol type phenol resin (trade name: PL-4852, manufactured by Gunei Chemical Industry Co., Ltd.), and an acrylic polymer example (1) 1.3 parts was dissolved in 73 parts of ethanol. This solution was dip-coated on the charge transport layer and cured by heating at 155 ° C. for 1 hour to form a protective layer (cured resin layer) having a thickness of 3 μm. This protective layer (cured resin layer) is also a second charge transport layer.

(Example 24)
In Example 23, an electrophotographic photosensitive member was produced in the same manner as in Example 23 except that the protective layer (cured resin layer) as the surface layer was formed as follows.

  That is, 9 parts of a charge transport material having a structure represented by the above formula (C-14), 8 parts of a partial polycondensate of tetramethoxysilane (trade name: methyl silicate-51, manufactured by Colcoat Co., Ltd.), and acrylic Polymer part (4) 1.3 parts was melt | dissolved in tetrahydrofuran 73 parts. This solution was spray-coated on the charge transport layer and heated at 155 ° C. for 1 hour to be cured to form a protective layer (cured resin layer) having a thickness of 3 μm. This protective layer (cured resin layer) is also a second charge transport layer.

(Example 25)
In Example 23, an electrophotographic photosensitive member was produced in the same manner as in Example 23 except that the protective layer (cured resin layer) as the surface layer was formed as follows.

  That is, 9 parts of a charge transport material having a structure represented by the above formula (C-31), 8 parts of an isocyanate resin (trade name: Sumidur N-3500, manufactured by Sumitomo Bayer Urethane Co., Ltd.), and an acrylic polymer example ( 5) 1.3 parts were dissolved in 63 parts of acetone. This solution was spray-coated on the charge transport layer and heated at 155 ° C. for 1 hour to be cured to form a protective layer (cured resin layer) having a thickness of 3 μm. This protective layer (cured resin layer) is also a second charge transport layer.

(Example 26)
In Example 23, an electrophotographic photosensitive member was produced in the same manner as in Example 23 except that the protective layer (cured resin layer) as the surface layer was formed as follows.

  That is, 9 parts of a charge transport material having a structure represented by the above formula (C-9), 8 parts of an amino resin (trade name: Cymel S-720, manufactured by Mitsui Cytec Co., Ltd.), and an acrylic polymer example (3) 1.3 parts were dissolved in 73 parts of ethyl acetate. This solution was spray-coated on the charge transport layer and heated at 155 ° C. for 1 hour to be cured to form a protective layer (cured resin layer) having a thickness of 3 μm. This protective layer (cured resin layer) is also a second charge transport layer.

(Examples 27 to 32)
In Example 23, the charge transport materials in the protective layer (cured resin layer) are each represented by the above formulas (C-34), (C-51), (C-38), (C-56), (C-61). An electrophotographic photosensitive member was produced in the same manner as in Example 23 except that the charge transporting material having the structure represented by (C-62) was used.

(Comparative Example 11)
In Example 22, an electrophotographic photosensitive member was produced in the same manner as in Example 22 except that the acrylic polymer was not added to the protective layer (cured resin layer) and acetone as the solvent was changed to ethanol.

(Comparative Example 12)
In Example 23, an electrophotographic photosensitive member was produced in the same manner as in Example 23 except that the protective layer (cured resin layer) as the surface layer was formed as follows.

  That is, 9 parts of a charge transport material having a structure represented by the above formula (C-51) and 8 parts of an amino resin (trade name: Cymel S-370, manufactured by Mitsui Cytec Co., Ltd.) are dissolved in 73 parts of acetone. did. This solution was spray-coated on the charge transport layer and heated at 155 ° C. for 1 hour to be cured to form a protective layer (cured resin layer) having a thickness of 3 μm. This protective layer (cured resin layer) is also a second charge transport layer.

(Comparative Example 13)
In Comparative Example 12, an electrophotographic photosensitive member was produced in the same manner as Comparative Example 12, except that 9 parts of the acrylic polymer example (9) was added to the protective layer (cured resin layer) coating solution.

(Comparative Example 14)
In Comparative Example 13, an electrophotographic photosensitive member was produced in the same manner as Comparative Example 13, except that the acrylic polymer example (9) in the protective layer (cured resin layer) was changed to the acrylic polymer example (10).

(Evaluation 4)
Regarding the electrophotographic photoreceptors prepared in Examples 21 to 32 and Comparative Examples 11 to 14, first, the surface state was observed, and then, as in Evaluation 1, a laser printer LBP-NX (charging roller) manufactured by Canon Inc. Using a contact charging means (applied voltage is a voltage obtained by superimposing an AC voltage on a DC voltage and a cleaning means using a urethane rubber cleaning blade), as in evaluation 1, temperature 5 ° C./humidity 15 RH% A durability test of 7000 sheets was performed in two environments (LL environment) and a temperature of 32.5 ° C./humidity of 80 RH% (HH environment).

Evaluation items are
(4-1) Observation result of surface condition (4-2) Image quality after durability in LL environment,
(4-3) Potential fluctuation in the LL environment (difference between the initial part and the bright part potential after continuous 50 sheets output),
(4-4) Image quality after endurance in HH environment,
(4-5) The contact angle of water on the surface of the electrophotographic photoreceptor after durability in an HH environment.

  The evaluation results are shown in Table 6.

  From the evaluation results shown in Table 6, the electrophotographic photosensitive member having a protective layer (cured resin layer) containing the acrylic polymer of the present invention as a surface layer is stable and good in image quality after a durability test, It can be seen that the potential fluctuation is quite small, and the surface contact angle with water is maintained at a high level.

  In the case of an electrophotographic photosensitive member (Comparative Example 14) having a protective layer (cured resin layer) containing an acrylic polymer having no alkylene oxide unit and only a polyfluoroolefin unit, the surface was high before image output The contact angle with respect to water became equivalent to that of the electrophotographic photosensitive member without addition of the acrylic polymer (Comparative Example 12) at the very initial stage of the durability test. This is presumably because the acrylic polymer was unevenly distributed on the surface side of the surface layer (protective layer (cured resin layer)) because there was no anchor effect due to the alkylene oxide unit or alkylene unit.

  Among the acrylic polymers, an electrophotographic photoreceptor (Comparative Example 13) having a surface layer (protective layer (cured resin layer)) containing an acrylic polymer having only an alkylene oxide unit and not having a polyfluoroolefin unit. In addition to large potential fluctuations, the contact angle of the electrophotographic photosensitive member surface with water in the HH environment was greatly reduced, resulting in image flow.

  The surfaces of the electrophotographic photosensitive members of Examples 26 and 28 were slightly cloudy although they were at a level that did not cause a large practical problem. This is because the solvent used in forming the protective layer (cured resin layer) as the surface layer has a δa smaller than 2.5 (δa = 2.0 for both ethyl acetate and diethyl ether). It is considered that the solubility of the coalescence was not so high.

  Although some repellency of the coating liquid for the protective layer (cured resin layer) was observed on the surfaces of the electrophotographic photoreceptors of Comparative Examples 12 and 13, the protective layer was formed using the coating liquid containing the acrylic polymer of the present invention. No repelling was found on the surface of the electrophotographic photosensitive member on which the (cured resin layer) was formed. It has been found that by adding the acrylic polymer of the present invention, a leveling action can be obtained when a layer having a high polarity is provided on a resin surface having a relatively low polarity such as a charge transport layer.

  Scratches occurring on the surfaces of the electrophotographic photoreceptors of Examples 21 to 32 after endurance compared to the scratches occurring on the surfaces of the electrophotographic photoreceptors of Examples 1 to 7 and Comparative Examples 11 to 14 after endurance It was found that the durability of the electrophotographic photoreceptor is further improved by containing the acrylic polymer of the present invention in the protective layer (cured resin layer).

(Example 33)
In the same manner as in Comparative Example 1, an intermediate layer, a charge generation layer, and a charge transport layer were formed on the support.

  Next, a siloxane compound having a repeating structural unit represented by the following formula

50 parts of antimony-doped conductive tin oxide particles (trade name: T-1, manufactured by Mitsubishi Materials Corp., average particle size: 0.03 μm) surface-treated with a surface treatment of 6.5% are added to 150 parts of ethanol. And dispersed for 72 hours in a sand mill. To this dispersion, 0.85 part of acrylic polymer example (4) and 15 parts of polytetrafluoroethylene (PTFE) particles (trade name: L-2, manufactured by Daikin Chemical Industries, Ltd.) were added and homogenizer. The solution was stirred until the solution became homogeneous, and PTFE particles were dispersed using a microfluidizer (manufactured by Tsukishima Kikai Co., Ltd.) at a pressure of 58.9 MPa (600 kgf / cm ² ). The volume average particle diameter of the PTFE particles after dispersion was 0.19 μm.

  In this dispersion, 30 parts of a resol type phenol resin (trade name: XPL-8264E, manufactured by Gunei Chemical Industry Co., Ltd.) is dissolved, and this solution is spray-coated on the charge transporting layer, and then at 155 ° C. for 1 hour. It heated and hardened and formed the protective layer (cured resin layer) with a film thickness of 3 micrometers.

  In this way, an electrophotographic photoreceptor having a protective layer (cured resin layer) as a surface layer was produced.

(Example 34)
In Example 33, electrophotography was performed in the same manner as in Example 33 except that the phenol resin in the protective layer (cured resin layer) was changed to an amino resin (trade name: Cymel C-701, manufactured by Mitsui Cytec Co., Ltd.). A photoconductor was prepared.

  The volume average particle size of the PTFE particles after dispersion was 0.21 μm.

(Example 35)
In Example 33, an electrophotographic photosensitive member was produced in the same manner as in Example 33 except that the protective layer (cured resin layer) as the surface layer was formed as follows.

That is, to 100 parts of ethanol, 0.75 parts of acrylic polymer example (2) and 10 parts of polytetrafluoroethylene (PTFE) particles (trade name: L-2, manufactured by Daikin Chemical Industries, Ltd.) are added. The mixture was stirred with a homogenizer until the solution became uniform, and PTFE particles were dispersed at a pressure of 58.9 MPa (600 kgf / cm ² ) using a microfluidizer (manufactured by Tsukishima Kikai Co., Ltd.). The volume average particle diameter of the PTFE particles after dispersion was 0.22 μm.

  In this dispersion, 22 parts of a charge transport material having the structure represented by the above formula (C-9) and 28 parts of a phenol resin (trade name: PL-4852, manufactured by Gunei Chemical Industry Co., Ltd.) are dissolved. Was spray-coated on the charge transport layer and cured by heating at 155 ° C. for 1 hour to form a protective layer (cured resin layer) having a thickness of 3 μm. This protective layer (cured resin layer) is also a second charge transport layer.

(Example 36)
In Example 35, the acrylic polymer example (2) in the protective layer (cured resin layer) is changed to the acrylic polymer example (3), and the charge transport material having the structure represented by the above formula (C-9) is represented by the above formula. The charge transport material having the structure represented by (C-4) is changed, the phenol resin is changed to an amino resin (trade name: Cymel C-701, manufactured by Mitsui Cytec Co., Ltd.), and the PTFE particles are changed to silicone resin particles ( An electrophotographic photosensitive member was produced in the same manner as in Example 35 except that the product name was changed to Tospearl 103, manufactured by Toshiba Silicone Co., Ltd.

  The volume average particle size of the dispersed silicone resin particles was 0.35 μm.

(Example 37)
In Example 35, the acrylic polymer example (2) in the protective layer (cured resin layer) is changed to the acrylic polymer example (5), and the charge transport material having the structure represented by the above formula (C-9) is represented by the above formula. Example 35, except that the charge transport material having the structure represented by (C-31) was changed and the phenol resin was changed to an isocyanate resin (trade name: Sumidur N-3500, manufactured by Sumitomo Bayer Urethane Co., Ltd.). An electrophotographic photoreceptor was produced in the same manner as described above.

  The volume average particle diameter of the PTFE particles after dispersion was 0.24 μm.

(Example 38)
In Example 35, the acrylic polymer example (2) in the protective layer (cured resin layer) is changed to the acrylic polymer example (6), and the charge transport material having the structure represented by the above formula (C-9) is represented by the above formula. Example 35, except that the charge transport material having the structure represented by (C-14) was changed and the phenol resin was changed to a tetramethoxysilane condensate (trade name: Methyl silicate 51, manufactured by Colcoat Co., Ltd.). An electrophotographic photoreceptor was produced in the same manner as described above.

  The volume average particle size of the PTFE particles after dispersion was 0.25 μm.

(Example 39)
In Example 35, the acrylic polymer example (2) in the protective layer (cured resin layer) is changed to the acrylic polymer example (1), and the charge transport material having the structure represented by the above formula (C-9) is represented by the above formula. The same procedure as in Example 35 was followed, except that the charge transport material having the structure represented by (C-36) was changed and the PTFE particles were changed to silicone resin particles (trade name: Tospearl 103, manufactured by Toshiba Silicone Co., Ltd.). Thus, an electrophotographic photosensitive member was produced.

  The volume average particle size of the dispersed silicone resin particles was 0.37 μm.

(Example 40)
In Example 35, the charge transport material having the structure represented by the above formula (C-9) in the protective layer (cured resin layer) was changed to the charge transport material having the structure represented by the above formula (C-38). An electrophotographic photosensitive member was produced in the same manner as in Example 35 except for the above.

  The volume average particle diameter of the PTFE particles after dispersion was 0.23 μm.

(Example 41)
In Example 35, the acrylic polymer example (2) in the protective layer (cured resin layer) is changed to the acrylic polymer example (3), and the charge transport material having the structure represented by the above formula (C-9) is represented by the above formula. An electrophotographic photosensitive member was produced in the same manner as in Example 35 except that the charge transport material having the structure represented by (C-56) was used.

  The volume average particle diameter of the PTFE particles after dispersion was 0.27 μm.

(Example 42)
In Example 35, the acrylic polymer example (2) in the protective layer (cured resin layer) is changed to the acrylic polymer example (1), and the charge transport material having the structure represented by the above formula (C-9) is represented by the above formula. An electrophotographic photosensitive member was produced in the same manner as in Example 35 except that the charge transporting material having the structure represented by (C-61) was used.

  The volume average particle diameter of the PTFE particles after dispersion was 0.24 μm.

(Example 43)
In Example 35, the acrylic polymer example (2) in the protective layer (cured resin layer) is changed to the acrylic polymer example (1), and the charge transport material having the structure represented by the above formula (C-9) is represented by the above formula. An electrophotographic photosensitive member was produced in the same manner as in Example 35 except that the charge transport material having the structure represented by (C-62) was used.

  The volume average particle size of the PTFE particles after dispersion was 0.21 μm.

(Example 44)
In Example 35, the acrylic polymer example (2) in the protective layer (cured resin layer) is changed to the acrylic polymer example (1), and the charge transport material having the structure represented by the above formula (C-9) is represented by the above formula. An electrophotographic photosensitive member was produced in the same manner as in Example 35 except that the charge transport material having the structure represented by (C-63) was used.

  The volume average particle size of the PTFE particles after dispersion was 0.22 μm.

(Example 45)
In Example 33, an electrophotographic photosensitive member was produced in the same manner as in Example 33 except that the protective layer (cured resin layer) as the surface layer was formed as follows.

That is, 0.75 parts of acrylic polymer example (1) and 10 parts of polytetrafluoroethylene (PTFE) particles (trade name: L-2, manufactured by Daikin Chemical Industries, Ltd.) are added to 100 parts of methanol. The mixture was stirred with a homogenizer until the solution became uniform, and PTFE particles were dispersed at a pressure of 58.9 MPa (600 kgf / cm ² ) using a microfluidizer (manufactured by Tsukishima Kikai Co., Ltd.). The volume average particle diameter of the PTFE particles after dispersion was 0.23 μm.

  In this dispersion, 40 parts of the charge transport material having the structure represented by the above formula (C-61) is dissolved, and this solution is spray-coated on the charge transport layer and heated at 155 ° C. for 1 hour to be cured. A protective layer (cured resin layer) having a thickness of 2 μm was formed. This protective layer (cured resin layer) is also a second charge transport layer.

(Example 46)
In Example 45, the charge transport material having the structure represented by the above formula (C-61) in the protective layer (cured resin layer) was changed to the charge transport material having the structure represented by the above formula (C-62). An electrophotographic photosensitive member was produced in the same manner as in Example 45 except for the above.

  The volume average particle diameter of the PTFE particles after dispersion was 0.26 μm.

(Example 47)
In Example 45, the charge transport material having the structure represented by the above formula (C-61) in the protective layer (cured resin layer) was changed to the charge transport material having the structure represented by the above formula (C-63). An electrophotographic photosensitive member was produced in the same manner as in Example 45 except for the above.

  The volume average particle diameter of the PTFE particles after dispersion was 0.27 μm.

(Comparative Example 15)
In Example 34, an electrophotographic photosensitive member was produced in the same manner as in Example 34 except that the acrylic polymer was not added to the protective layer (cured resin layer).

  The PTFE particles after dispersion had a volume average particle size of 2.11 μm.

(Comparative Example 16)
In Example 36, an electrophotographic photosensitive member was produced in the same manner as in Example 36 except that the acrylic polymer was not added to the protective layer (cured resin layer).

  The volume average particle size of the dispersed silicone resin particles was 1.87 μm.

(Comparative Example 17)
In Example 36, an electrophotographic photosensitive member was produced in the same manner as in Example 36 except that the acrylic polymer example (3) in the protective layer (cured resin layer) was changed to the acrylic polymer example (9).

  The volume average particle size of the dispersed silicone resin particles was 1.02 μm.

(Comparative Example 18)
In Example 36, an electrophotographic photosensitive member was produced in the same manner as in Example 36 except that the acrylic polymer example (3) in the protective layer (cured resin layer) was changed to the acrylic polymer example (11).

  The volume average particle diameter of the dispersed silicone resin particles was 0.96 μm.

(Evaluation 5)
Regarding the electrophotographic photosensitive members produced in Examples 33 to 47 and Comparative Examples 15 to 18, as in Evaluation 1, a laser printer LBP-NX manufactured by Canon Inc. (contact charging means employing a charging roller (applied voltage is DC) And a cleaning means employing a urethane rubber cleaning blade) and a temperature of 5 ° C./humidity of 15 RH% (LL environment) and a temperature of 32.5 ° C. / Durability tests were conducted in two environments with a humidity of 80 RH% (HH environment). However, the durable number was changed from 7000 to 10,000.

Evaluation items are
(5-1) Image quality after endurance in the LL environment,
(5-2) Reproducibility of fine lines of images after endurance in LL environment,
(5-3) Potential fluctuation in the LL environment (difference between the initial part and the bright part potential after continuous 50 sheets output),
(5-4) Contact angle of water on the surface of the electrophotographic photosensitive member after durability in an HH environment,
(5-5) The amount of wear of the electrophotographic photosensitive member after continuously outputting 1000 sheets in an HH environment.

  Table 7 shows the evaluation results.

  From the evaluation results shown in Table 7, the electrophotographic photosensitive member containing both the curable resin and the acrylic polymer of the present invention in the protective layer, which is the surface layer, has an extremely small amount of wear in the durability test and reproduction of fine lines. In the durability test under the HH environment, it is recognized that the contact angle with water on the surface is maintained at a high level even though the wear amount is extremely small. Regarding the potential fluctuation, the electrophotographic photosensitive member containing the charge transport material in the surface layer has little fluctuation, and in particular, when the charge transport material is three-dimensionally crosslinked in the surface layer (Examples 45 to 47), Exhibits extremely stable characteristics.

  In contrast, the electrophotographic photosensitive member (Comparative Examples 15 and 16) in which the charge transport layer, which is the surface layer, does not contain the acrylic polymer of the present invention but contains the resin particles (Comparative Examples 15 and 16) results in poor reproducibility of fine lines. However, this is presumed as follows from the dispersed particle diameter of the resin particles in the charge transport layer coating solution. That is, in the electrophotographic photoconductors of Comparative Examples 15 and 16, the resin particles are considerably aggregated in the charge transport layer, whereby the exposure light is scattered and the electrostatic latent image is disturbed, so that the reproducibility of fine lines is inferior. It is thought that it became a result.

  Further, the peripheral scratches on the post-endurance images in Comparative Examples 15 to 17 are due to the peripheral scratches on the surface of the electrophotographic photosensitive member of Comparative Examples 15 to 17, and most of the starting points of the peripheral scratches are on the surface of the electrophotographic photosensitive member. It was a minute protrusion present in As a result of analyzing these minute protrusions, all were aggregates of resin particles. Further, some peripheral scratches were also observed on the post-endurance image in Comparative Example 18, which is presumed as follows. That is, since the molecular weight of the acrylic polymer used in Comparative Example 18 is too large and the solubility in the solvent is not sufficient, it is considered that the action of uniformly dispersing the resin particles (silicone resin particles) is reduced.

It is a figure which shows the example of the layer structure of the electrophotographic photoreceptor of this invention. 1 is a diagram illustrating an example of a schematic configuration of an electrophotographic apparatus including a process cartridge having the electrophotographic photosensitive member of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Layer containing acrylic polymer of this invention 2 Charge transport layer 3 Charge generation layer 4 Support body 5 Intermediate layer 6 Conductive layer 11 Electrophotographic photoreceptor 12 Shaft 13 Charging means 14 Exposure light 15 Developing means 16 Transfer means 17 Transfer material 18 Fixing means 19 Cleaning means 20 Pre-exposure light 21 Process cartridge 22 Guide means

Claims (16)

In an electrophotographic photoreceptor having a photosensitive layer on a support,
The surface layer of the electrophotographic photosensitive member has an acrylic polymer of any one of the following (i) to (iv) whose number average molecular weight is in the range of 2000 to 20000 with respect to the total mass of the surface layer. An electrophotographic photosensitive member containing 1 to 20% by mass:
(I) a copolymer obtained only from a first acrylic ester monomer having a polyfluoroolefin unit and a second acrylic ester monomer having an alkylene oxide unit;
(Ii) Only from the first acrylic acid ester monomer, the second acrylic acid ester monomer, and any acrylic acid alkyl ester selected from the following structural formulas (3A-1) to (3A-24) The resulting copolymer;
(Iii) a polymer obtained only from an acrylate monomer having a polyfluoroolefin unit and an alkylene oxide unit;
(Iv) a copolymer obtained only from an acrylate monomer having a polyfluoroolefin unit and an alkylene oxide unit and any one of the acrylate alkyl esters selected from the following structural formulas (3A-1) to (3A-24): Polymer:
(However, the polyfluoroolefin unit is a unit having 7 to 29 fluorine atoms per unit, the alkylene oxide unit is a unit having 2 to 4 carbon atoms per unit, and The molar ratio of the fluoroolefin unit to the alkylene oxide unit (R ^F : R ^O ) is 0.1: 1 to 2: 1)

.   The electrophotographic photosensitive member according to claim 1, wherein the polyfluoroolefin unit is a polyfluoroalkylene unit.   The electrophotographic photosensitive member according to claim 1, wherein the alkylene oxide unit is an ethylene oxide unit.   The electrophotographic photosensitive member according to claim 1, wherein the surface layer of the electrophotographic photosensitive member contains at least one of fluorine atom-containing resin particles and silicon atom-containing resin particles.   The electrophotographic photosensitive member according to claim 1, wherein the surface layer of the electrophotographic photosensitive member contains a curable resin as a binder resin.   The electrophotographic photosensitive member according to claim 1, wherein the surface layer of the electrophotographic photosensitive member contains a charge transport material.   The electrophotographic photosensitive member according to claim 6, wherein the surface layer of the electrophotographic photosensitive member is a layer formed using a coating solution for a surface layer containing a charge transport material having a hydroxy group.   The electrophotographic photosensitive member according to claim 6 or 7, wherein the charge transport material in the surface layer of the electrophotographic photosensitive member is three-dimensionally crosslinked.   The surface layer of the electrophotographic photoreceptor is a layer formed using a coating solution for a surface layer containing an organic solvent having a proton acceptor parameter of 2 or more and a boiling point of 50 to 120 ° C. The electrophotographic photosensitive member according to any one of the above.   The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer is a laminated photosensitive layer in which a charge generation layer and a charge transport layer are laminated in this order from the support side.   The electrophotographic photosensitive member according to claim 10, wherein the surface layer of the electrophotographic photosensitive member is a layer not in contact with the charge generation layer.   The electrophotographic photosensitive member according to any one of claims 1 to 11, wherein the content of the charge generating substance in the surface layer of the electrophotographic photosensitive member is 0 to 5000 ppm (mass ratio) with respect to the total mass of the surface layer. The electrophotographic photosensitive member according to claim 1, wherein the molar ratio (R ^F : R ^O ) is 0.2: 1 to 1: 1. The surface layer is a protective layer covering the charge transport layer, and the protective layer further includes a charge transport agent and a resol type phenol resin, and the charge transport agent is represented by any one of the following formulas C61 to 63: the electrophotographic photosensitive member according to any one of claims 1 to 13 are intended to be:

. Detachable and an electrophotographic photosensitive member according to any one of claims 1 to 14 charging means, developing means, and at least one means selected from the group consisting of transfer means and a cleaning means integrally supported, in an electrophotographic apparatus A process cartridge that is free to use. The electrophotographic photosensitive member according to any one of claims 1-14, a charging means, an exposure means, the electrophotographic apparatus, characterized in that it comprises a developing means and transfer means.

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