JP2007193309A - Electrophotographic photoreceptor, method for manufacturing electrophotographic photoreceptor, process cartridge and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which stably maintains good wear resistance and cleanability in a sustainable way. <P>SOLUTION: An outermost surface layer of the electrophotographic photoreceptor contains a polyarylate resin containing a repeating structural unit represented by formula (1) in an amount of 60-100% by mol based on the amount of all repeating structural units and any one or a mixture of polytrifluoroethylene and perfluoropolyether, wherein R<SP>11</SP>-R<SP>18</SP>and R<SP>21</SP>-R<SP>28</SP>each denote H, alkyl, aryl or the like; and X denotes a single bond, O or the like or a divalent group of formula (2), wherein R<SP>31</SP>and R<SP>32</SP>each denote H, alkyl fluoroalkyl or the like. A method for manufacturing the electrophotographic photoreceptor, and a process cartridge and an electrophotographic apparatus having the electrophotographic photoreceptor are also provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  Photoconductive materials (charge generating materials and charge transport materials) used for electrophotographic photoreceptors mounted on electrophotographic apparatuses include inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide. Organic photoconductive substances have been actively developed from the viewpoints of pollution-free, high productivity, and ease of material design.

  An electrophotographic photosensitive member (organic electrophotographic photosensitive member) using an organic photoconductive substance is obtained by applying a coating liquid obtained by dissolving and dispersing an organic photoconductive substance or a binder resin in a solvent on a support, Those having a photosensitive layer formed by drying this are usually used. The layer structure of the photosensitive layer is generally a laminate type (normal layer type) in which a charge generation layer and a charge transport layer are laminated in this order from the support side.

  An electrophotographic photoreceptor using an organic photoconductive material has the above-mentioned advantages, but does not satisfy all the characteristics required for an electrophotographic photoreceptor at a high level. In particular, the outermost surface layer of the electrophotographic photoreceptor is required to have durability against various electric and mechanical external forces directly applied by the electrophotographic process. Specifically, the surface of the photoconductor deteriorates due to charging, so that there are problems such as deterioration in image characteristics and cleanability, and wear and scratches caused by rubbing against various members and paper. It is desired to further improve the durability of the layer.

As a technique for improving the surface properties of such an electrophotographic photosensitive member, by adding silicone oil to the outermost surface layer of the electrophotographic photosensitive member, the coating properties, image blurring, cleaning properties and filming properties of the outermost surface layer are improved. The technique which performs is disclosed (for example, refer patent document 1 and 2). However, the compatibility between the silicone oil and the binder resin is not always good, and the durability of the outermost surface layer composed of the low molecular weight charge transporting material and the binder resin is low. There is room for improvement in the sustainability of the effect obtained by the addition. As one means for solving such a problem, a technique for continuously improving the wear properties and image characteristics by using an outermost surface layer composed of a polymer charge transport material and a fluorine oil is disclosed (for example, Patent Documents). 3). However, the polymer charge transporting material is more difficult than the low molecular weight charge transporting material, and the polymer charge transporting material that satisfies both electrical characteristics and mechanical strength can be stably produced. There are still many technical issues. In addition, since the binding force to the fluorine oil varies depending on the molecular weight and structure of the polymer charge transport material, it is difficult to achieve a stable effect by adding the fluorine oil.
JP 11-38654 A JP 2001-255675 A JP-A-11-258843

  An object of the present invention is to have an electrophotographic photosensitive member having an outermost surface layer that stably and continuously maintains good wear resistance and cleaning properties, a method for producing the electrophotographic photosensitive member, and the electrophotographic photosensitive member. To provide a process cartridge and an electrophotographic apparatus.

  The present invention relates to an electrophotographic photosensitive member having a conductive support and a photosensitive layer on the conductive support, wherein the outermost surface layer of the electrophotographic photosensitive member includes a repeating structural unit represented by the following general formula (1). An electrophotography comprising a polyarylate resin containing 60% or more and 100% or less in terms of molar ratio in all repeating structural units, and one or a mixture of polytrifluoroethylene and perfluoropolyether It is a photoreceptor.

(In formula (1), R ¹¹ -R ¹⁸ and R ²¹ -R ²⁸ each independently represent hydrogen, an alkyl group having 1-4 carbon atoms, an aryl group, or an alkoxy group having 1-3 carbon atoms. X represents , A single bond, an oxygen atom, a sulfur atom, or a divalent group represented by the following general formula (2).

(In the formula (2), R ³¹ and R ³² each independently represent a hydrogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group or an aryl group, or R ³¹ and R ³² are bonded to each other. A cycloalkylidene group or a fluorenylidene group).

  The present invention also provides an electrophotographic photosensitive member having a conductive support and a photosensitive layer on the conductive support, wherein the outermost surface layer of the electrophotographic photosensitive member is represented by the general formula (1). Coating solution containing polyarylate resin containing 60% or more and 100% or less of repeating structural units in terms of molar ratio in all repeating structural units, and one or a mixture of polytrifluorinated ethylene and perfluoropolyether It is a manufacturing method of the electrophotographic photoreceptor characterized by forming by this.

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

  According to the present invention, an electrophotographic photosensitive member that has high durability and can be stably cleaned even after repeated use over a long period of time, a method for producing the electrophotographic photosensitive member, a process cartridge and an electronic device having the electrophotographic photosensitive member A photographic device can be provided.

  Hereinafter, the present invention will be described in detail.

  The polytrifluoroethylene in the present invention is a low polymer of ethylene trifluoride chloride and preferably has a weight average molecular weight (MW) of 500 or more and 1000 or less. Moreover, it is preferable that the weight average molecular weight (MW) of the perfluoropolyether in this invention is 2000 or more and 9000 or less. Specific examples of these are shown in Table 1, but the present invention is not limited thereto. In Table 1, m and n are average values representing the number of repetitions.

  The polyarylate resin in the present invention is characterized by containing at least a repeating structural unit represented by the following general formula (1).

(In formula (1), R ¹¹ -R ¹⁸ and R ²¹ -R ²⁸ each independently represent hydrogen, an alkyl group having 1-4 carbon atoms, an aryl group, or an alkoxy group having 1-3 carbon atoms. X represents , A single bond, an oxygen atom, a sulfur atom, or a divalent group represented by the following general formula (2).

(In the formula (2), R ³¹ and R ³² each independently represent a hydrogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group or an aryl group, or R ³¹ and R ³² are bonded to each other. A cycloalkylidene group or a fluorenylidene group).

Examples of the alkyl group having 1 to 4 carbon atoms represented by R ^{11 to} R ¹⁸ and R ^{21 to} R ²⁸ in the above formula (1) include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the alkoxy group 1-3 include a methoxy group, an ethoxy group, and a propoxy group, and examples of the aryl group include a phenyl group and a naphthyl group. Among these, a methyl group, an ethyl group, and a methoxy group An ethoxy group and a phenyl group are preferred.

Examples of the alkyl group represented by R ³¹ and R ³² in the above formula (2) include a methyl group, an ethyl group, a propyl group, and a butyl group, and examples of the fluorinated alkyl group include a trifluoromethyl group and pentafluoro group. Examples include an ethyl group, examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Examples of the aryl group include a phenyl group and a naphthyl group. Among these, a methyl group , Ethyl group, propyl group (particularly isopropyl group), trifluoromethyl group, and pentafluoroethyl group are preferable.

Examples of the cycloalkylidene group formed by combining R ³¹ and R ³² in the above formula (2) include a cyclopentylidene group, a cyclohexylidene group, and a cycloheptylidene group. Among these, a cyclohexylidene group is preferable.

  Specific examples of the repeating structural unit represented by the above formula (1) are shown below.

  The polyarylate resin in the present invention contains the repeating structural unit represented by the above formula (1) in a range of 60% to 100% in terms of molar ratio in all repeating structural units. When the repeating structural unit represented by the formula (1) is less than 60%, compatibility with any one of polytrifluorinated ethylene and perfluoropolyether or a mixture thereof (hereinafter also referred to as a fluorine-based compound) is sufficient. descend. Therefore, the repeating structural unit represented by the formula (1) is 60% or more, and preferably 80% or more.

  The polyarylate resin having a repeating structural unit represented by the above formula (1) used for the outermost surface layer of the electrophotographic photoreceptor of the present invention is a specific repeating structural unit selected from the above formula (1). And other repeating structural units selected from the above formula (1), or a copolymer of another divalent carboxylic acid and a repeating structural unit composed of a divalent organic residue. . In this case, the polymerization form may be a polymerization form such as block copolymerization or random copolymerization and is arbitrary, but a random copolymerization form is preferred.

  Further, in the present invention, the specific repeating structural unit selected in the above formula (1), the other repeating structural units selected in the above formula (1), or other divalent carboxylic acids. The description that the copolymerization ratio in terms of molar ratio of the copolymerized polyarylate resin having a repeating structural unit composed of an acid and a divalent organic residue is A: B is a specific formula selected from the above formula (1). The dicarboxylic acid ester moiety shown in the repeating structural unit is (1-C), the bisphenol moiety is (1-B), another repeating structural unit selected from the above formula (1), or other divalent carboxylic acid When the dicarboxylic acid ester moiety shown in the repeating structural unit consisting of an acid and a divalent organic residue is (3-C) and the bisphenol moiety is (3-B), the dicarboxylic acid ester moiety in terms of molar ratio is (1-C) :( 3-C) is the copolymerization ratio A: B, and (1-B) :( 3-B) in the bisphenol moiety in terms of molar ratio is the copolymerization ratio A: B. It shows that there is.

  Examples of the divalent carboxylic acid used in the repeating structural unit composed of the other divalent carboxylic acid and the divalent organic residue include terephthalic acid, isophthalic acid, diphenyldicarboxylic acid, naphthalenedicarboxylic acid, 3,4 Aromatic divalent carboxylic acids such as' -diphenyl ether dicarboxylic acid and 3,3'-diphenyl ether dicarboxylic acid, linear aliphatic divalent carboxylic acids such as succinic acid, adipic acid, sebacic acid and dodecanedioic acid, cyclohexylene dicarboxylic acid, etc. Examples thereof include cycloaliphatic divalent carboxylic acids, among which terephthalic acid, isophthalic acid, adipic acid, and sebacic acid are preferable. Examples of the divalent organic residue include bisphenols such as 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) and 2,2-bis (3-methyl-4-hydroxyphenyl) propane (bisphenol C), Biphenols such as 4,4′-hydroxybiphenyl are included.

  Specific examples of repeating structural units composed of other divalent carboxylic acids and divalent organic residues are shown below.

  The weight average molecular weight (MW) of the polyarylate resin having the repeating structural unit represented by the above formula (1) used for the outermost surface layer of the electrophotographic photoreceptor of the present invention is arbitrary, but the weight average molecular weight (MW) is When it is 80,000 or more, the effect of sustaining the cleaning property by the addition of the fluorine compound is improved. However, if the molecular weight of the polyarylate resin having the repeating structural unit represented by the above formula (1) is too large, the coating property of the coating solution containing this may be deteriorated. The weight average molecular weight (MW) of the polyarylate resin having a repeating structural unit is preferably 300,000 or less, particularly preferably 200,000 or less.

  The polyarylate resin having a repeating structural unit represented by the above formula (1) used in the outermost surface layer of the electrophotographic photosensitive member of the present invention or the coating solution for the outermost surface layer of the electrophotographic photosensitive member is a dicarboxylic acid ester and a hydroxyl group. It is also possible to synthesize by a transesterification method with a compound having a hydrogen atom, and also by a polymerization reaction between a divalent acid halide such as a dicarboxylic acid halide and a compound having a hydroxyl group such as bisphenol. However, in order to produce a product having a weight average molecular weight (MW) in the above range, the latter synthesis method is preferred.

(Synthesis Example 1)
Hereinafter, as a synthesis example, a method for synthesizing a polyarylate resin in which 100% in terms of molar ratio among all the repeating structural units in the polyarylate resin is a repeating structural unit represented by the above formula (1-2) is shown.

  The following formula (1-2-1)

Diphenyl ether dicarboxylic acid chloride having a structure represented by the following formula was dissolved in dichloromethane to prepare an acid chloride solution.

  In addition to the acid chloride solution, the following formula (1-2-2)

2,2-bis (3-methyl-4-hydroxyphenyl) propane having a structure represented by the following formula is dissolved in a 10% aqueous sodium hydroxide solution, and tributylbenzylammonium chloride as a polymerization catalyst is added thereto and stirred: A 2,2-bis (3-methyl-4-hydroxyphenyl) propane solution was prepared.

  Next, the acid chloride solution was added to the 2,2-bis (3-methyl-4-hydroxyphenyl) propane solution with stirring to initiate polymerization. The polymerization was carried out for 3 hours while maintaining the reaction temperature at 25 ° C. or lower and stirring.

  Thereafter, the polymerization reaction was terminated by the addition of acetic acid, and washing with water was repeated until the aqueous phase became neutral.

  After washing, the solution was dropped into methanol with stirring to precipitate a polymer, and this polymer was vacuum-dried to obtain a polyarylate resin which is a repeating structural unit represented by the above formula (1-2). This polyarylate resin had a weight average molecular weight in terms of polystyrene (denoted as “weight average molecular weight (MW)” in the present specification) of 130,000.

(Synthesis Example 2)
Below, as a synthesis example, in all repeating structural units in the polyarylate resin, 70% in terms of molar ratio is a repeating structural unit represented by the above formula (1-2), and 30% is represented by the above formula (3-9). The synthesis method of the polyarylate resin which is a repeating structural unit shown by this is shown.

  The following formula (1-2-1)

Diphenyl ether dicarboxylic acid chloride having a structure represented by the following formula (3-9-1):

Was mixed at a molar ratio of 7: 3 and dissolved in dichloromethane to prepare a mixed solution of diphenyl ether dicarboxylic acid chloride and terephthalic acid chloride.

  In addition to the acid chloride solution, the following formula (1-2-2)

2,2-bis (3-methyl-4-hydroxyphenyl) propane having a structure represented by the following formula (3-9-2)

Is mixed at a molar ratio of 7: 3, dissolved in a 10% aqueous sodium hydroxide solution, tributylbenzylammonium chloride as a polymerization catalyst is added and stirred, and 2,2-bis (3 -Methyl-4-hydroxyphenyl) propane and tetramethylbiphenol mixed solution was prepared.

  Next, the acid chloride solution was added to 2,2-bis (3-methyl-4-hydroxyphenyl) propane and tetramethylbiphenol mixed solution with stirring to initiate polymerization. The polymerization was carried out for 3 hours while maintaining the reaction temperature at 25 ° C. or lower and stirring.

  Thereafter, the polymerization reaction was terminated by the addition of acetic acid, and washing with water was repeated until the aqueous phase became neutral.

  After washing, the solution is added dropwise to methanol with stirring to precipitate a polymer, and this polymer is vacuum-dried. In all the repeating structural units in the polyarylate resin, 70% in terms of molar ratio is represented by the formula (1- A polyarylate resin having the repeating structural unit represented by 2) and 30% of the repeating structural unit represented by the above formula (3-9) was obtained. The weight average molecular weight (MW) of this polyarylate resin was 130,000.

(Synthesis Example 3)
Hereinafter, as a synthesis example, in all repeating structural units in the polyarylate resin, 70% in terms of molar ratio is a repeating structural unit represented by the above formula (1-2), and 30% is represented by the above formula (3-13). The synthesis method of the polyarylate resin which is a repeating structural unit shown by this is shown.

  The following formula (1-2-1)

Diphenyl ether dicarboxylic acid chloride having a structure represented by the following formula (3-13-1)

Were mixed at a molar ratio of 7: 3 and dissolved in dichloromethane to prepare a mixed solution of diphenyl ether dicarboxylic acid chloride and isophthalic acid chloride.
In addition to the acid chloride solution, the following formula (1-2-2)

2,2-bis (3-methyl-4-hydroxyphenyl) propane having a structure represented by the following formula is dissolved in a 10% aqueous sodium hydroxide solution, and tributylbenzylammonium chloride as a polymerization catalyst is added thereto and stirred: A 2,2-bis (3-methyl-4-hydroxyphenyl) propane solution was prepared.
Next, the acid chloride solution was added to the 2,2-bis (3-methyl-4-hydroxyphenyl) propane solution with stirring to initiate polymerization. The polymerization was carried out for 3 hours while maintaining the reaction temperature at 25 ° C. or lower and stirring. Thereafter, the polymerization reaction was terminated by the addition of acetic acid, and washing with water was repeated until the aqueous phase became neutral.

  After washing, the solution is added dropwise to methanol with stirring to precipitate a polymer, and this polymer is vacuum-dried. In all the repeating structural units in the polyarylate resin, 70% in terms of molar ratio is represented by the formula (1- A polyarylate resin having a repeating structural unit represented by 2) and 30% of a repeating structural unit represented by the above formula (3-13) was obtained. The weight average molecular weight (MW) of this polyarylate resin was 120,000.

  In the present invention, the weight average molecular weight (MW) of the resin is measured as follows according to a conventional method.

  That is, the measurement target resin is placed in tetrahydrofuran and allowed to stand for several hours, and then the measurement target resin and tetrahydrofuran are mixed well while shaking (mix until the measurement target resin is completely united), and then left to stand for 12 hours or more. did.

  Then, what passed the sample processing filter Mysori disk H-25-5 by Tosoh Corporation was made into the sample for GPC (gel permeation chromatography).

  Next, the column is stabilized in a heat chamber at 40 ° C., tetrahydrofuran is flowed through the column at this temperature at a flow rate of 1 ml / min, 10 μl of GPC sample is injected, and the weight average molecular weight of the measurement target resin (MW) was measured. A column TSKgel Super HM-M manufactured by Tosoh Corporation was used as the column.

  In measuring the weight average molecular weight (MW) of the measurement target resin, the molecular weight distribution of the measurement target resin was calculated from the relationship between the logarithmic value of the calibration curve created by several monodisperse polystyrene standard samples and the count number. . Ten standard polystyrene samples for preparing a calibration curve were used from Aldrich monodisperse polystyrene having a molecular weight of 800 to 2,000,000. An RI (refractive index) detector was used as the detector.

  The coating solution for forming the outermost surface layer of the electrophotographic photosensitive member of the present invention is any one or a mixture of the polyarylate resin, polytrifluorinated ethylene and perfluoropolyether of the present invention, a solvent, preferably a charge. A transport material is mixed and stirred. Moreover, you may add a leveling agent, antioxidant, a plasticizer, etc. to this coating liquid as needed.

  When the outermost surface layer is formed, the photoreceptor is formed by applying the above-described coating solution. Solvents used at this time include ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as methyl acetate and ethyl acetate, aromatic hydrocarbon solvents such as toluene, xylene and chlorobenzene, 1,4-dioxane, tetrahydrofuran and the like. And ether solvents, hydrocarbon solvents substituted with halogen atoms such as chloroform, and the like. These solvents may be used alone or in combination of two or more. Among these solvents, it is preferable to use at least an ether solvent from the viewpoint of resin solubility and the like.

  Next, the configuration of the electrophotographic photosensitive member of the present invention will be described.

  The electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor having a support and a photosensitive layer provided on the support, and the constitution thereof is a photoreceptor having a photosensitive layer containing a charge generating substance and a charge transporting substance. (Single layer type) or a laminated type (functional separation type) separated into a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material may be used. A laminate type photoreceptor is preferred in view of the body characteristics. Further, it is more preferably 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. Further, a protective layer may be provided on the charge transport layer for the purpose of protecting the photosensitive layer or imparting surface properties.

  In the present invention, the outermost surface layer containing any one of polyarylate resin, polytrifluoroethylene and perfluoropolyether or a mixture thereof is the entire photosensitive layer in a single layer type photosensitive member, and a laminated type photosensitive member In FIG. 2, it is a charge transport layer or a protective layer.

  The support is only required to have conductivity, and specifically, a support made of metal (made of alloy) such as aluminum, an aluminum alloy, and stainless steel can be used. Moreover, the said metal support body and plastic support body which have a 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. Also, a support in which conductive particles such as carbon black, tin oxide particles, titanium oxide particles, and silver particles are impregnated into plastic or paper together with an appropriate binder resin, or a plastic support having a conductive binder resin. Etc. can also be used. In addition, examples of the shape of the support include a cylindrical shape and a belt shape, and a cylindrical shape is preferable.

  The surface of the support may be subjected to cutting treatment, roughening treatment, anodizing treatment, etc. for the purpose of preventing interference fringes due to scattering of laser light or the like.

  Between the support and the photosensitive layer (charge generation layer, charge transport layer) or an intermediate layer described later, there is a conductive layer for the purpose of preventing interference fringes due to scattering of laser light or the like and for coating the scratch on the support. It may be provided.

  The conductive layer can be formed by dispersing conductive particles such as carbon black, metal particles, and metal oxide particles in a binder resin.

  The thickness of the conductive layer is preferably 1 μm or more and 40 μm or less, and particularly preferably 2 μm or more and 20 μm or less.

  Further, 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 is acrylic resin, allyl resin, alkyd resin, ethyl cellulose resin, ethylene-acrylic acid copolymer, epoxy resin, casein resin, silicone resin, gelatin resin, polyamide resin, phenol resin, butyral resin, polyacrylate resin, polyacetal resin, Polyamideimide resin, polyallyl ether resin, polyimide resin, polyurethane resin, polyester resin, polyethylene resin, polycarbonate resin, polystyrene resin, polysulfone resin, polyvinyl alcohol resin, polybutadiene resin, polypropylene resin, urea resin, aluminum oxide, etc. It can be formed using the material.

  The thickness of the intermediate layer is preferably 0.05 μm or more and 5 μm or less, and particularly preferably 0.3 μm or more and 1 μm or less.

  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 anhydride, perylene imide, polycyclic quinone pigments such as anthraquinone, pyrenequinone, dibenzpyrenequinone, squarylium dyes, pyrylium and thiapyrylium salts, triphenylmethane dyes, selenium, Inorganic substances such as selenium-tellurium and amorphous silicon, quinacridone pigments, azurenium salt pigments, cyanine dyes such as quinocyanine, anthanthrone pigments, pyranthrone pigments, xanthene dyes, quinoneimine dyes, Dyes and, and cadmium sulfide, zinc oxide and the like. These charge generation materials may be used alone or in combination of two or more.

  When the photosensitive layer is a laminated type photosensitive layer and the charge generation layer is not the outermost surface layer of the electrophotographic photosensitive member, examples of the binder resin used for the charge generation layer include acrylic resins, allyl resins, and alkyds. Resin, epoxy resin, diallyl phthalate resin, silicone resin, styrene-butadiene copolymer, polyamide resin, phenol resin, butyral resin, benzaal resin, polyacrylate resin, polyacetal resin, polyamideimide resin, polyallyl ether resin, polyarylate resin, polyimide Resin, polyurethane resin, polyester resin, polyethylene resin, polycarbonate resin, polystyrene resin, polysulfone resin, polyvinyl acetal resin, polybutadiene resin, polypropylene resin, methacrylic resin, urea resin, vinyl chloride - vinyl acetate copolymer, vinyl acetate resins, and vinyl chloride resins. In particular, a butyral resin is preferable. These can be used singly or in combination of two or more as a mixture or copolymer.

  The charge generation layer can be formed by applying a charge generation layer coating solution obtained by dispersing a charge generation material together with a binder resin and a solvent and drying the coating solution. Examples of the dispersion method include a method using a homogenizer, an ultrasonic disperser, a ball mill, a sand mill, a roll mill, a vibration mill, an attritor, a liquid collision type high-speed disperser, and the like. The ratio between the charge generation material and the binder resin is preferably in the range of 1: 4 or more and 1: 0.3 or less (mass ratio).

  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 to be used. As the organic solvent, alcohol, sulfoxide, ketone, ether, ester, aliphatic Examples thereof include halogenated hydrocarbons and aromatic compounds.

  The thickness of the charge generation layer is preferably 5 μm or less, particularly preferably 0.1 μm or more and 2 μm or less.

  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, and triarylmethane compounds. These charge transport materials may be used alone or in combination of two or more.

  When the charge transport layer is the outermost surface layer, the charge transport layer contains at least a repeating structural unit represented by the above formula (1) as a binder resin in terms of a molar ratio in the total repeating structural unit of the polyarylate resin of 60. A polyarylate resin containing from 100% to 100% is used. Other resins exemplified below can be used in combination as long as the effects of the present invention are not impaired. In that case, the repeating structural unit represented by the above formula (1) in the charge transport layer is all of the polyarylate resin. The ratio of the polyarylate resin containing 60% or more and 100% or less in terms of molar ratio in the repeating structural unit is preferably 50% by mass or more with respect to the total mass of the binder resin contained in the charge transport layer, and Is preferably 70% by mass or more. Examples of resins that can be used in combination include acrylic resins, acrylonitrile resins, allyl resins, alkyd resins, epoxy resins, silicone resins, polyamide resins, phenol resins, phenoxy resins, butyral resins, polyacrylamide resins, polyacetal resins, polyamideimide resins, Polyallyl ether resin, polyarylate resin, polyimide resin, polyurethane resin, polyester resin, polyethylene resin, polycarbonate resin, polystyrene resin, polysulfone resin, polyvinyl butyral resin, polyphenylene oxide resin, polybutadiene resin, polypropylene resin, methacrylic resin, urea resin, A vinyl chloride resin, a vinyl acetate resin, etc. are mentioned. In particular, polyarylate resin, polycarbonate resin and the like are preferable. These can be used singly or in combination of two or more as a mixture or copolymer.

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

  Solvents used in the coating solution for the charge transport layer include ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as toluene and xylene, ethers such as 1,4-dioxane and tetrahydrofuran, Hydrocarbons substituted with halogen atoms such as chlorobenzene, chloroform and carbon tetrachloride are used.

  The thickness of the charge transport layer is preferably 5 μm or more and 40 μm or less, and particularly preferably 10 μm or more and 35 μm or less.

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

  Further, a protective layer for the purpose of protecting the photosensitive layer may be provided on the photosensitive layer. The protective layer can be formed by applying a protective layer coating solution obtained by dissolving a binder resin in a solvent and drying the coating solution.

  The thickness of the protective layer is preferably 0.5 μm or more and 10 μm or less, and particularly preferably 1 μm or more and 5 μm or less.

  When applying the coating liquid for each of the above layers, for example, a coating method such as a dip coating method (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 should be used. Can do.

  FIG. 1 shows an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.

  In FIG. 1, reference numeral 1 denotes a cylindrical electrophotographic photosensitive member, which is rotationally driven in a direction of an arrow about a shaft 2 at a predetermined peripheral speed.

  The surface of the electrophotographic photosensitive member 1 that is rotationally driven is uniformly charged to a predetermined positive or negative potential by a charging unit (primary charging unit: charging roller or the like) 3, and then subjected to slit exposure, laser beam scanning exposure, or the like. Exposure light (image exposure light) 4 output from exposure means (not shown) is received. In this way, electrostatic latent images corresponding to the target image are sequentially formed on the surface of the electrophotographic photosensitive member 1.

  The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is developed with toner contained in the developer of the developing means 5 to become a toner image. Next, the toner image formed and supported on the surface of the electrophotographic photoreceptor 1 is transferred from a transfer material supply means (not shown) to the electrophotographic photoreceptor 1 and the transfer means by a transfer bias from a transfer means (transfer roller or the like) 6. 6 is transferred to a transfer material (paper or the like) 7 taken out and fed in synchronization with the rotation of the electrophotographic photosensitive member 1.

  The transfer material 7 that has received the transfer of the toner image is separated from the surface of the electrophotographic photosensitive member 1 and is introduced into the fixing means 8 to be image-fixed to be printed out as an image formed product (print, copy). Is done.

  The surface of the electrophotographic photosensitive member 1 after the transfer of the toner image is cleaned by a cleaning means (cleaning blade or the like) 9 to remove the developer (toner) remaining after transfer, and further from a pre-exposure means (not shown). After being subjected to the charge removal process with the pre-exposure light 10, it is repeatedly used for image formation. The exposure means preferably has a laser having an oscillation wavelength in the range of 380 nm to 450 nm. As shown in FIG. 1, when the charging unit 3 is a contact charging unit using a charging roller or the like, pre-exposure is not necessarily required.

  Among the above-described components such as the electrophotographic photosensitive member 1, the charging unit 3, the developing unit 5, the transfer unit 6 and the cleaning unit 7, 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. In FIG. 1, an electrophotographic photosensitive member 1, a charging unit 3, a developing unit 5 and a cleaning unit 9 are integrally supported to form a cartridge, and an electrophotographic apparatus is provided using a guide unit 12 such as a rail of the electrophotographic apparatus main body. The process cartridge 11 is detachable from the main body.

  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”. “MW” means “weight average molecular weight (MW)”.

[Example 1]
An aluminum cylinder having a diameter of 30 mm and a length of 260.5 mm was used as a support.

Next, SnO ₂ coat-treated barium sulfate (conductive particles) 10 parts, titanium oxide (resistance pigment) 2 parts, phenol resin (binder resin) 6 parts, silicone oil (leveling agent) 0.001 part and methanol A conductive layer coating solution was prepared using a mixed solvent of 4 parts / 16 parts of methoxypropanol.

  This conductive layer coating solution was dip-coated on a support and thermally cured at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 15 μm.

  Next, an intermediate layer coating solution was prepared by dissolving 3 parts of N-methoxymethylated nylon and 3 parts of copolymer nylon in a mixed solvent of 65 parts of methanol / 30 parts of n-butanol.

  This intermediate layer coating solution was dip-coated on the conductive layer and dried at 100 ° C. for 10 minutes to form an intermediate layer having a thickness of 0.7 μm.

  Next, strong peaks at 7.5 °, 9.9 °, 16.3 °, 18.6 °, 25.1 ° and 28.3 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction 10 parts of a crystalline form of hydroxygallium phthalocyanine (charge generating substance) having the following structure is added to a solution obtained by dissolving 5 parts of polyvinyl butyral resin (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) in 250 parts of cyclohexanone, Dispersion was performed in a 23 ± 3 ° C. atmosphere for 1 hour with a sand mill using glass beads having a diameter of 1 mm, and after dispersion, 250 parts of ethyl acetate was added to prepare a charge generation layer coating solution. This charge generation layer coating solution was dip coated on the intermediate layer and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.26 μm.

  Next, 50 parts of a polyarylate resin (MW: 130000) having a repeating structural unit represented by the above formula (1-2), 40 parts of a charge transport material represented by the following structural formula (A), and Compound Example No. in Table 1 . 1 part of a fluorine compound was dissolved in 450 parts of tetrahydrofuran (THF) to prepare a coating solution for a charge transport layer. The charge transport layer coating solution was dip-coated on the charge generation layer and dried at 120 ° C. for 60 minutes to form a charge transport layer having a thickness of 30 μm.

  This photoconductor (1) is put into a copying machine GP-40 manufactured by Canon Inc., and the cleaning property is evaluated after printing 200 sheets in a normal temperature and humidity environment (23 ° C./55% RH) to print 20000 sheets. Later, the cleaning property was evaluated and the amount of wear was measured. In addition, printing was continued after 20000 sheets, and the number of printed sheets with a sustainable cleaning property was investigated. Further, another sample was prepared by the method described below, and the transmittance of the outermost surface layer was measured. The results are shown in Table 3-1.

  From these results, the photoconductor (1) maintains high durability even during repeated use and continuously exhibits stable cleaning properties, so that image defects such as spots due to fusion of the developer do not occur. It has become clear that a clear image can be stably obtained over a long period of time.

  Here, the evaluation method of transmittance, wear amount and cleaning property will be described in detail below.

<Measurement method of transmittance>
The transmittance is measured by applying a charge transport layer coating solution on a polyethylene terephthalate (PET) film with a Meyer bar to a film thickness of 20 μm in a normal temperature and humidity environment (25 ° C./50% RH). The dried film was peeled off and measured using V-570 (manufactured by JASCO Corporation). In addition, the film | membrane of the structure of the same material as this was used except having excluded the fluorine-type compound as a reference sample.

<Measurement method of wear amount>
The amount of abrasion of the photoconductor was measured by eddy current measurement (film thickness meter: Fisher Permascope) and interference film thickness meter (manufactured by Otsuka Electronics Co., Ltd.).

<Evaluation method for cleaning properties>
By visually confirming the surface of the photoreceptor, the cleaning blade and the output image, the cleaning (CLN) property was evaluated by paying attention to the presence / absence of developer fusion, the developer's streak-through, and the cleaning blade. We also investigated the presence or absence of abnormal sounds due to chatter during continuous printing.

[Example 2-21]
The electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the type, molecular weight, addition rate, and resin contained in the outermost surface layer were changed as shown in Tables 2-1 and 2-4. Fabricated and evaluated similarly. The results are shown in Table 3-1.

[Comparative Example 1-8]
The electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the type, molecular weight and addition rate of the fluorine compound, and the resin contained in the outermost surface layer were changed as shown in Table 2-3 and Table 2-6. Fabricated and evaluated similarly. The results are shown in Table 3-3.

[Example 22]
The charge generation layer was formed in the same manner as in Example 1. Next, 50 parts of a polycarbonate resin (MW: 100,000) having a repeating structural unit represented by the following formula (B) and 40 parts of a charge transport material represented by the structural formula (A) are dissolved in 450 parts of tetrahydrofuran (THF). Then, a coating liquid for charge transport layer was prepared. The charge transport layer coating solution was dip-coated on the charge generation layer and dried at 120 ° C. for 60 minutes to form a charge transport layer having a thickness of 25 μm. Furthermore, 50 parts of a polyarylate resin (MW: 50000) having a repeating structural unit represented by the above formula (1-11), 40 parts of a charge transport material represented by the above structural formula (A), and Compound Example No. 1 part of the fluorine-based compound 1 was dissolved in 450 parts of tetrahydrofuran (THF) to prepare a coating solution for the surface protective layer. The surface protective layer coating solution is dip-coated on the charge transport layer and dried at 120 ° C. for 60 minutes to form a surface protective layer having a thickness of 5 μm. And evaluated in the same manner. The results are shown in Table 3-2.

[Examples 23-34]
The electrophotographic photosensitive member was prepared in the same manner as in Example 22 except that the type, molecular weight and addition rate of the fluorine compound, and the resin contained in the outermost surface layer were changed as shown in Table 2-2 and Table 2-5. Fabricated and evaluated similarly. The results are shown in Table 3-2.

[Comparative Example 9-16]
The electrophotographic photosensitive member was prepared in the same manner as in Example 22 except that the type, molecular weight and addition rate of the fluorine compound, and the resin contained in the outermost surface layer were changed as shown in Table 2-3 and Table 2-6. Fabricated and evaluated similarly. The results are shown in Table 3-3.

[Examples 35-37]
The electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the type, molecular weight and addition rate of the fluorine compound, and the resin contained in the outermost surface layer were changed as shown in Table 2-2 and Table 2-5. Fabricated and evaluated similarly. The results are shown in Table 3-2.

[Comparative Example 17]
An electrophotographic photosensitive member is produced in the same manner as in Example 1 except that the type, molecular weight and addition rate of the fluorine compound, and the resin contained in the outermost surface layer are changed as shown in Tables 2-3 and 2-6. And evaluated in the same manner. The results are shown in Table 3-3.

[Examples 38-40]
The electrophotographic photosensitive member was prepared in the same manner as in Example 22 except that the type, molecular weight and addition rate of the fluorine compound, and the resin contained in the outermost surface layer were changed as shown in Table 2-2 and Table 2-5. Fabricated and evaluated similarly. The results are shown in Table 3-2.

[Comparative Example 18]
The electrophotographic photosensitive member was prepared in the same manner as in Example 22 except that the type, molecular weight and addition rate of the fluorine compound, and the resin contained in the outermost surface layer were changed as shown in Table 2-3 and Table 2-6. Fabricated and evaluated similarly. The results are shown in Table 3-3.

[Comparative Example 19]
Except for changing the polyarylate resin in Example 1 to the polycarbonate resin of the structural formula (B) (MW: 150,000) and changing the type, molecular weight and addition rate of the fluorine-based compound as shown in Table 2-3, An electrophotographic photosensitive member was produced in the same manner as in Example 1 and evaluated in the same manner. The results are shown in Table 3-3.

[Comparative Example 20]
The polyarylate resin in Example 1 was changed to the polyarylate resin (MW: 150,000) of the following structural formula (C), and the type, molecular weight, and addition rate of the fluorine-based compound were changed as shown in Table 2-3. In the same manner as in Example 1, an electrophotographic photosensitive member was produced and evaluated in the same manner. The results are shown in Table 3-3.

[Example 41]
As a charge generating compound, strong against 7.5 °, 9.9 °, 16.3 °, 18.6 °, 25.1 ° and 28.3 ° with Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction 2 parts of a crystalline hydroxygallium phthalocyanine pigment having a peak, 50 parts of a compound represented by the structural formula (A) as a charge transporting substance, 50 parts of a compound represented by the following structural formula (D) as an electron transporting compound, the above formula 100 parts of a polyarylate resin (MW: 100,000) having the repeating structural units represented by (1-5) and (3-5), Compound Example No. A coating solution for a single-layer photosensitive layer was prepared by mixing and dispersing 3.0 parts of 1 fluorine-based compound in a ball mill using 800 parts of tetrahydrofuran as a solvent. The coating solution was applied on an anodized aluminum cylinder having a diameter of 30 mm and a length of 260.5 mm, and then dried at 120 ° C. for 60 minutes to produce a single layer type photoreceptor having a thickness of 30 μm. And evaluated in the same manner. The results are shown in Table 3-2.

From the above experimental results, the following is clear.

  The photoreceptor having the outermost surface layer of the present invention can maintain a good cleaning property for a long time.

  From Examples 1-7 and 22-25, the molecular weight of the polyarylate resin in the photoreceptor of the present invention is preferably 80,000 to 300,000, more preferably 80,000 to 200,000.

  -From the comparison of Example 2 and 8, Example 3 and 9, Example 23 and 26, and Example 24 and 27, the polyarylate resin which has a methyl group in a predetermined position is preferable.

  -From Example 10-15 and Example 28-30, it is preferable that the addition amount of a fluorine-type compound is 0.1 to 5.0 mass%. From Examples 36, 37, 39, and 40, several types of fluorine compounds may be used in combination.

  -From Example 16-20 and 31-34, the fluorine-type compound which has a specific molecular weight is preferable.

  From Example 1-40 and Comparative Example 1-20, the transmittance at 680 nm is preferably 95% or more.

  Therefore, the electrophotographic photosensitive member having the outermost surface layer of the present invention can maintain a good cleaning property for a long period of time and supply a stable and clear image.

1 is a schematic view showing an embodiment of a process cartridge having an electrophotographic photosensitive member of the present invention and an electrophotographic apparatus including the process cartridge.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Axis 3 Primary charging means 4 Image exposure light 5 Developing means 6 Transfer means 7 Transfer material 8 Image fixing means 9 Cleaning means 10 Pre-exposure light 11 Process cartridge 12 Rail

Claims (14)

In an electrophotographic photosensitive member having a conductive support and a photosensitive layer on the conductive support, the outermost surface layer of the electrophotographic photosensitive member represents all repeating structural units represented by the following general formula (1) An electrophotographic photoreceptor comprising a polyarylate resin containing 60% or more and 100% or less in terms of an intermediate molar ratio, and one or a mixture of polytrifluoroethylene and perfluoropolyether.

(In formula (1), R ¹¹ -R ¹⁸ and R ²¹ -R ²⁸ each independently represent hydrogen, an alkyl group having 1-4 carbon atoms, an aryl group, or an alkoxy group having 1-3 carbon atoms. X represents , A single bond, an oxygen atom, a sulfur atom, or a divalent group represented by the following general formula (2).

(In the formula (2), R ³¹ and R ³² each independently represent a hydrogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group or an aryl group, or R ³¹ and R ³² are bonded to each other. A cycloalkylidene group or a fluorenylidene group).   2. The electrophotographic photosensitive member according to claim 1, wherein the polyarylate resin has a weight average molecular weight (MW) of 80,000 or more and 300,000 or less. The electrophotographic photoreceptor according to claim 1, wherein R ²¹ and R ^{26 in} the general formula (1) are methyl groups.   The content of any one of the polytrifluoroethylene and perfluoropolyether or a mixture thereof is from 0.1% by mass to 5.0% by mass with respect to the mass of the polyarylate resin. The electrophotographic photosensitive member according to claim 1.   The weight average molecular weight (MW) of the polytrifluorinated ethylene is 500 or more and 1000 or less, and the weight average molecular weight (MW) of the perfluoropolyether is 2000 or more and 9000 or less. The electrophotographic photosensitive member according to any one of the above.   6. The photosensitive layer according to claim 1, wherein the photosensitive layer has a charge generation layer and a charge transport layer on the charge generation layer, and the transmittance of the charge transport layer at a wavelength of 680 nm is 95% or more. An electrophotographic photoreceptor according to any one of the above. In the method for producing an electrophotographic photosensitive member having a conductive support and a photosensitive layer on the conductive support, the outermost surface layer of the electrophotographic photosensitive member is entirely composed of repeating structural units represented by the following general formula (1). It is characterized in that it is formed from a polyarylate resin containing 60% or more and 100% or less in terms of molar ratio in the repeating structural unit, and a coating solution containing any one of polytrifluoroethylene and perfluoropolyether or a mixture thereof. A method for producing an electrophotographic photosensitive member.

(In formula (1), R ¹¹ -R ¹⁸ and R ²¹ -R ²⁸ each independently represent hydrogen, an alkyl group having 1-4 carbon atoms, an aryl group, or an alkoxy group having 1-3 carbon atoms. X represents , A single bond, an oxygen atom, a sulfur atom, or a divalent group represented by the following general formula (2).

(In the formula (2), R ³¹ and R ³² each independently represent a hydrogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group or an aryl group, or R ³¹ and R ³² are bonded to each other. A cycloalkylidene group or a fluorenylidene group).   The weight average molecular weight (MW) of the said polyarylate resin is 80000-300000, The manufacturing method of Claim 7 characterized by the above-mentioned. The production method according to claim 7, wherein R ²¹ and R ^{26 in} the general formula (1) are methyl groups.   The content of any one of the polytrifluoroethylene and perfluoropolyether or a mixture thereof is from 0.1% by mass to 5.0% by mass with respect to the mass of the polyarylate resin. The manufacturing method according to claim 7.   The weight average molecular weight (MW) of the polytrifluoroethylene is 500 or more and 1000 or less, and the weight average molecular weight (MW) of the perfluoropolyether is 2000 or more and 9000 or less. The manufacturing method in any one of.   7. The electrophotographic photosensitive member according to claim 1 and at least one unit selected from the group consisting of a charging unit, a developing unit, and a cleaning unit are integrally supported and detachable from the electrophotographic apparatus. A process cartridge characterized by that.   An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1, a charging unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit.   The electrophotographic apparatus according to claim 13, wherein the exposure unit includes a laser having an oscillation wavelength in a range of 380 nm to 450 nm.