JP6476893B2 - Electrophotographic photosensitive member, electrophotographic photosensitive member cartridge, image forming apparatus, and manufacturing method of electrophotographic photosensitive member - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member having excellent initial electrical characteristics and stability against a transfer voltage during repeated use, an electrophotographic photosensitive member cartridge produced using the electrophotographic photosensitive member, an image forming apparatus, and an electrophotographic photosensitive member. It relates to the manufacturing method.

The electrophotographic technology is widely used as a copying machine, a printer, and a printing machine because a high-quality image can be obtained immediately. The electrophotographic photoreceptor (hereinafter referred to as “photoreceptor” as appropriate), which is the core of electrophotographic technology, is a photosensitive material that uses organic photoconductive materials and has the advantages of being pollution-free and easy to form and manufacture. The body is widely used.
Electrophotographic image forming apparatuses are required to have higher image quality, higher speed, and higher durability year by year. Processes around the photoconductor such as charging, exposure, development, and transfer have been improved to meet these requirements, but there are still many cases where improvement of the photoconductor itself is still necessary.

  For example, in order to meet the demand for higher speed, it is necessary to increase the electrical responsiveness by quickly attenuating the surface potential in a short time from exposure to development. In order to increase the electrical response of the photoreceptor, it is usually necessary to increase the ratio of the charge transport material to the binder resin in the photosensitive layer and increase the mobility of the charge. As a result, the entanglement density of the binder resin is reduced, whereby the photosensitive layer is easily worn and cannot meet the demand for high durability. Furthermore, in order to transfer from the photoreceptor to the paper in a shorter time, it is necessary to increase the applied voltage. In particular, a color machine uses four colors of toner, and the thickness of the toner layer is increased as compared with a monochrome machine, so that a higher transfer voltage is applied.

  Under such circumstances, a charge transport material having a large conjugated system as described in Patent Documents 1 and 2 exhibits a large charge mobility and a very low residual potential. There is a possibility of both. In Patent Document 3, a specific polyarylate resin and a non-halogen solvent such as tetrahydrofuran are used to develop a high-quality and long-life photoconductor in order to achieve both the above-mentioned mechanical characteristics and electrical characteristics. Manufacturing an electrophotographic photosensitive member is described.

Japanese Patent Laid-Open No. 9-292724 JP 2000-162791 A JP 2006-293391 A

  Since the charge transport material described in Patent Document 1 has a small polarity as a molecule and a large conjugated system, it has a sufficiently large charge mobility in the film thickness direction even when dispersed in a binder resin. However, according to the study by the inventors, the charge transport material described in Patent Document 1 has a low solubility in a solvent because of its conjugation, and it is necessary to select a solvent that dissolves well, such as a halogen solvent. It was. Therefore, if a photosensitive layer is formed using the charge transport material and a halogen solvent, a strong transfer voltage is repeatedly applied to the photosensitive member, whereby the chargeability and light attenuation characteristics of the photosensitive member change, and the image portion -It has been found that there is a problem that image defects occur between non-image areas.

  Moreover, as described in Patent Document 2, high durability can be realized by using a binder resin having a high molecular weight, but in that case, the solubility of the binder resin in a solvent is low. Therefore, use with a high molecular weight binder resin and a charge transport material having low solubility is expected to cause image defects due to insufficient dispersion of the coating liquid. Actually, in Examples of Patent Documents 1 and 2, a photoreceptor that can withstand practical use is obtained by using a binder resin having a small molecular weight.

  The present invention has been made in view of the above-mentioned background art, and its problem is that it has high response that can withstand high-speed printing and sufficient wear resistance that is indispensable for long-life use, and is a transfer voltage during repeated use. An electrophotographic photosensitive member, an electrophotographic photosensitive member cartridge, an image forming apparatus, and a method of manufacturing the electrophotographic photosensitive member having stability against the above.

  As a result of intensive studies, the inventor has a photosensitive layer containing a specific charge transporting substance and a binder resin having a specific viscosity within a specific range on a conductive support, and the photosensitive layer contains an ether solvent. By using a coating solution for forming a photosensitive layer that has a specific mass ratio (charge transport material / solvent), sufficient abrasion resistance is essential for long-life use. The electrophotographic photosensitive member, the electrophotographic photosensitive member cartridge, the image forming apparatus, which have the stability to the transfer voltage during repeated use without adversely affecting the electrical characteristics by addition while maintaining the properties, are less likely to cause image defects, In addition, the inventors have found that it is possible to provide a method for producing an electrophotographic photoreceptor, and have completed the present invention described below.

The gist of the present invention resides in the following <1> to <12>.
<1> In an electrophotographic photosensitive member having a photosensitive layer containing a charge transport material represented by formula (1) and a binder resin on a conductive support, the viscosity average molecular weight of the binder resin is from 40,000 to 100,000. An electrophotographic photoreceptor, wherein the photosensitive layer is formed using an ether solvent.

(In the formula (1), Ar ^{1 to} Ar ⁵ each represents an aryl group which may have an independent substituent, and Ar ^{6 to} Ar ⁹ may each have an independent substituent. -Represents a phenylene group, m and n each independently represents an integer of 1 to 3.
<2> The electrophotographic photosensitive member according to <1>, wherein the charge transport material represented by the formula (1) has a purity of 98.0% to 99.7%.
<3> Crystalline type oxy where the photosensitive layer shows a diffraction peak at a Bragg angle (2θ ± 0.2 °) of at least 24.1 ° and 27.2 ° in a powder X-ray diffraction spectrum by CuKα characteristic X-ray. The electrophotographic photosensitive member according to <1> or <2>, which contains titanium phthalocyanine.

<4> The charge transport material represented by the above formula (1) contained in the photosensitive layer is 20 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the binder resin forming the photosensitive layer. The electrophotographic photosensitive member according to any one of <1> to <3>.
<5> The photosensitive layer is formed from a coating solution using an organic solvent, the residual amount of the halogen-based solvent in the photosensitive layer is 1.0 mg / g or less, and the residual amount of the non-halogen-based solvent is 0. The electrophotographic photosensitive member according to any one of <1> to <4>, wherein the electrophotographic photosensitive member is 0.05 mg / g or more and 20.0 mg / g or less.

<6> The electrophotographic photosensitive member according to any one of <1> to <5>, a charging device for charging the electrophotographic photosensitive member, and exposing the charged electrophotographic photosensitive member to form an electrostatic latent image. An electrophotographic photosensitive member cartridge comprising: an exposure device for forming; and at least one selected from the group consisting of a developing device for developing an electrostatic latent image formed on the electrophotographic photosensitive member .
<7> The electrophotographic photosensitive member according to any one of <1> to <5>, a charging device that charges the electrophotographic photosensitive member, and an electrostatic latent image formed by exposing the charged electrophotographic photosensitive member A full-color tandem type image forming apparatus, comprising: an exposure apparatus for forming the image forming apparatus; and a developing apparatus for developing the electrostatic latent image formed on the electrophotographic photosensitive member.

<8> In the method for producing an electrophotographic photosensitive member having a photosensitive layer containing a charge transport material represented by the above formula (1) and a binder resin on a conductive support, the mass of the charge transport material and the solvent The photosensitive layer forming coating solution is adjusted so that the ratio [charge transporting material / solvent] is 1/10 to 1/100. The solvent contains an ether solvent, and the photosensitive layer forming coating is prepared. A method for producing an electrophotographic photosensitive member, comprising forming a photosensitive layer using a solution.
<9> The method for producing an electrophotographic photosensitive member according to <8>, wherein the charge transport material represented by the formula (1) has a purity of 98.0% to 99.7%.

<10> The method for producing an electrophotographic photosensitive member according to <8> or <9>, wherein the charge transport material represented by the formula (1) is produced using a palladium catalyst. .
<11> The method for producing an electrophotographic photosensitive member according to any one of <8> to <10>, wherein the binder resin has a viscosity average molecular weight of 40,000 to 100,000.
<12> The method for producing an electrophotographic photosensitive member according to any one of <8> to <11>, wherein the charge transport material is heated and dissolved in the solvent to prepare a coating solution for forming a photosensitive layer. .

  The present invention is an electrophotographic photosensitive member that maintains sufficient abrasion resistance, which is indispensable for long-life use, has stability against a transfer voltage during repeated use, and does not adversely affect electrical characteristics, and that hardly causes image defects. It is possible to provide an electrophotographic photosensitive member cartridge and an image forming apparatus.

1 is a schematic diagram illustrating a main configuration of an embodiment of an image forming apparatus of the present invention. 1 is a schematic diagram illustrating a main configuration of an embodiment of a tandem full-color image forming apparatus according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail. However, the description of the constituent elements described below is a representative example of the embodiments of the present invention, and is appropriately modified and implemented without departing from the spirit of the present invention. can do.
<Charge transport material>
The charge transport material used in the present invention is represented by the following formula (1).

(In the formula (1), Ar ^{1 to} Ar ⁵ each represents an aryl group which may have an independent substituent, and Ar ^{6 to} Ar ⁹ may each have an independent substituent. -Represents a phenylene group, m and n each independently represents an integer of 1 to 3.
In the above formula (1), Ar ^{1 to} Ar ⁵ each independently represents an aryl group which may have a substituent. The number of carbon atoms of the aryl group is 30 or less, preferably 20 or less, more preferably 15 or less. Specific examples include a phenyl group, a naphthyl group, a biphenyl group, an anthryl group, and a phenanthryl group. Among these, in consideration of the characteristics of the electrophotographic photosensitive member, a phenyl group, a naphthyl group, and an anthryl group are preferable. From the viewpoint of charge transport capability, a phenyl group and a naphthyl group are more preferable, and a phenyl group is further preferable. Examples of the substituent that Ar ^{1 to} Ar ⁵ may have include an alkyl group, an alkoxy group, and a halogen atom. Specifically, examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, and an n group. -A linear alkyl group such as a butyl group, a branched alkyl group such as an isopropyl group or an ethylhexyl group, or a cyclic alkyl group such as a cyclohexyl group. As the aryl group, a phenyl group which may have a substituent , Naphthyl groups, etc., and examples of the alkoxy group include linear alkoxy groups such as methoxy group, ethoxy group, n-propoxy group and n-butoxy group, and branched alkoxy groups such as isopropoxy group and ethylhexyloxy group. , Cyclic alkoxy groups such as cyclohexyloxy group, trifluoromethoxy group, pentafluoroethoxy group, 1,1,1-trifluoroethoxy They include alkoxy groups having a fluorine atom in groups such as the halogen atom fluorine atom, chlorine atom, bromine atom and the like. Among these, an alkyl group having 1 to 20 carbon atoms and an alkoxy group having 1 to 20 carbon atoms are preferable from the versatility of production raw materials, and an alkyl group having 1 to 12 carbon atoms and carbon number from the viewpoint of handleability during production. An alkoxy group having 1 to 12 carbon atoms is more preferable, and an alkyl group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms are more preferable from the viewpoint of light attenuation characteristics as an electrophotographic photoreceptor. In the case where Ar ^{1 to} Ar ⁵ are phenyl groups, it is preferable to have a substituent from the viewpoint of charge transport ability, and the number of substituents can be 1 to 5, but from the versatility of manufacturing raw materials, 1 1 to 3 are preferable, and from the viewpoint of the characteristics of the electrophotographic photosensitive member, 1 to 2 are more preferable, and when Ar ^{1 to} Ar ⁵ are naphthyl groups, the number of substituents from the versatility of the production raw material Is preferably 2 or less or not having a substituent, and more preferably, the number of substituents is 1 or having no substituent. Ar ¹ preferably has at least one substituent at the ortho-position or para-position relative to the nitrogen atom, and the substituent is preferably an alkyl group having 1 to 4 carbon atoms from the viewpoint of electrical properties, and has solubility. In view of the above, an alkoxy group having 1 to 6 carbon atoms or an alkyl group having 1 to 12 carbon atoms is preferable, and a methyl group, an ethyl group, a methoxy group, and an ethoxy group are more preferable from the viewpoint of characteristics and productivity of the photoreceptor.

In the above formula (1), Ar ^{6 to} Ar ⁹ each represent a 1,4-phenylene group even if each has an independent substituent. As the substituent that Ar ^{6 to} Ar ⁹ may have, those exemplified as the substituent that Ar ^{1 to} Ar ⁵ may have are applicable. Among these, a C1-C6 alkyl group and a C1-C6 alkoxy group are preferable from the versatility of a manufacturing raw material, and a C1-C4 alkyl group and carbon number from the surface of the handling property at the time of manufacture 1-4 alkoxy groups are more preferable, and a methyl group, an ethyl group, a methoxy group, and an ethoxy group are more preferable from the viewpoint of light attenuation characteristics as an electrophotographic photosensitive member. When Ar ^{6 to} Ar ⁹ have a substituent, the molecular structure is twisted, and π-conjugate expansion in the molecule may be hindered, and the electron transport ability may be reduced. Therefore, Ar ^{6 to} Ar ⁹ may be substituted. It is preferable not to have.

  m and n each independently represent an integer of 1 to 3. When m and n are large, the solubility in a coating solvent tends to decrease. Therefore, it is preferably 2 or less, and more preferably 1 from the viewpoint of charge transport ability as a charge transport material. When m and n are 1, it represents an ethenyl group and has a geometric isomer, but a trans structure is preferable from the viewpoint of the characteristics of an electrophotographic photoreceptor. When m and n are 2, it represents a butadienyl group, which also has a geometric isomer, but is preferably a mixture of two or more geometric isomers from the viewpoint of coating solution storage stability.

The electrophotographic photoreceptor of the present invention may contain the compound represented by the formula (1) as a single component in the photosensitive layer, or may contain it as a mixture of the compounds represented by the formula (1). Is possible.
Moreover, the compound represented by the following formula (1a) is particularly preferable. In formula (1a), Ar ¹ in formula (1) is a phenyl group having an alkyl group, an alkoxy group, an aryloxy group, or an aralkyloxy group, and Ar ^{2 to} Ar ⁵ are each independently a substituent. It is a phenyl group which may have an alkyl group having 1 to 6 carbon atoms, Ar ^{6 to} Ar ⁹ are all unsubstituted 1,4-phenylene groups, and m and n are both 1.

(In formula (1a), R ^{a to} R ^e represent a hydrogen atom, an alkyl group, an alkoxy group, an aryloxy group, or an aralkyloxy group.)
The ratio between the binder resin in the photosensitive layer and the charge transport material represented by the formula (1) is usually 15 parts by mass or more of the charge transport material with respect to 100 parts by mass of the binder resin in the same layer. To do. 20 parts by mass or more is preferable from the viewpoint of residual potential reduction, and 25 parts by mass or more is more preferable from the viewpoint of stability and charge mobility when repeatedly used. On the other hand, from the viewpoint of thermal stability of the photosensitive layer, the charge transport material is usually used at 70 parts by mass or less. 65 parts by mass or less is preferable from the viewpoint of compatibility between the compound represented by the formula (1) and the binder resin, 60 parts by mass or less is more preferable from the viewpoint of heat resistance, and 50 parts by mass or less is preferable from the viewpoint of scratch resistance. More preferred is 45 parts by mass or less from the viewpoint of wear resistance.

  The structure of the charge transport material suitable for the present invention is exemplified below. The following structures are illustrated to make the present invention more concrete, and are not limited to the following structures unless departing from the concept of the present invention.

<Method for producing charge transport material>
The charge transport materials exemplified above can be produced according to the scheme described below.
Taking the above compound as an example, it can be produced, for example, by reacting a compound having a triphenylamine skeleton having a formyl group with a phosphate compound having a triphenylamine skeleton. (Scheme 1)

  As another production method, it can also be produced by performing a coupling reaction between a triphenylamine derivative having a halogen atom as described below and an aniline compound.

  Among the above schemes 1 and 2, scheme 2 is preferable from the viewpoint of production cost, and in scheme 2, it is more preferable to use palladium as a catalyst from the viewpoint of purity and electrical characteristics. The purity is preferably 97.0% or more, more preferably 97.5% or more, and still more preferably 98.0% or more from the viewpoint of electrical characteristics. From the viewpoint of solubility, it is preferably 99.9% or less, more preferably 99.8% or less, and still more preferably 99.7% or less. As a method of achieving 97.0% or more, a production method in which a palladium compound is combined with a ligand having a phosphorus atom as a catalyst can be used. On the other hand, methods for achieving 99.9% or less include purification methods such as crystallization and adsorbent treatment. For example, in order to achieve 98.0% or more and 99.7% or less, it is preferable to purify by a method using an adsorbent. Impurities include catalysts, isomers, substrates, reaction intermediates, by-products, etc. From the viewpoint of solubility and electrical properties, impurities that may remain are carbon, hydrogen, and nitrogen such as isomers. And a compound having a tertiary amine structure is more preferable. The charge transport material can be identified by NMR, IR, mass spectrum or the like. Purity can be calculated by liquid chromatography. The liquid chromatograph can be measured by the method described in Examples using an apparatus having a UV-vis detector.

≪Electrophotographic photoreceptor≫
The configuration of the electrophotographic photosensitive member of the present invention will be described below. The electrophotographic photoreceptor of the present invention contains, on the conductive support, the charge transport material represented by the above formula (1) and a binder resin having a viscosity average molecular weight of 40,000 to 100,000 in the same layer. The constitution is not particularly limited as long as it has a photosensitive layer formed using a solvent containing an ether solvent. In the case where the photosensitive layer of the electrophotographic photosensitive member is a laminated type described later, the charge transporting layer, the charge transport material represented by the formula (1), the binder resin, and other antioxidants as necessary , Leveling agents, and other additives. In addition, when the electrophotographic photosensitive layer is a single layer type, which will be described later, in addition to the components used for the charge transport layer of the above-mentioned multilayer photoconductor, a charge generating material and an electron transport material may be used. It is common.

<Conductive support>
There are no particular restrictions on the conductive support, but for example, metal materials such as aluminum, aluminum alloys, stainless steel, copper and nickel, and conductive powders such as metal, carbon and tin oxide can be added to make the conductive material conductive. Mainly used are resin, glass, paper, or the like obtained by depositing or applying the applied resin material or a conductive material such as aluminum, nickel, ITO (indium tin oxide) on the surface. These may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and arbitrary ratios. As a form of the conductive support, a drum form, a sheet form, a belt form or the like is used. Furthermore, a conductive material having an appropriate resistance value may be used on a conductive support made of a metal material in order to control conductivity and surface properties and to cover defects.

Moreover, when using metal materials, such as an aluminum alloy, as an electroconductive support body, you may use, after giving an anodic oxide film. When an anodized film is applied, it is desirable to perform a sealing treatment by a known method.
The surface of the conductive support may be smooth, or may be roughened by using a special cutting method or performing a polishing treatment. Further, it may be roughened by mixing particles having an appropriate particle size with the material constituting the conductive support. In order to reduce the cost, it is possible to use the drawing tube as it is without performing the cutting process.

<Underlayer>
An undercoat layer may be provided between the conductive support and the photosensitive layer described later for improving adhesion and blocking properties. As the undercoat layer, a resin or a resin in which particles such as a metal oxide are dispersed is used. The undercoat layer may be a single layer or a plurality of layers.

  Examples of metal oxide particles used for the undercoat layer include metal oxide particles containing one metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, titanium Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid and barium titanate. One kind of these particles may be used alone, or a plurality of kinds of particles may be mixed and used. Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicon. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. Moreover, the thing of a several crystal state may be contained.

In addition, various particle sizes of metal oxide particles can be used. Among these, from the viewpoint of characteristics and liquid stability, the average primary particle size is preferably 10 nm or more and 100 nm or less, and particularly 10 nm or more and 50 nm or less. preferable. This average primary particle size can be obtained from a TEM photograph or the like.
The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. As the binder resin used for the undercoat layer, epoxy resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate resin, polyurethane resin, polyimide resin, Cellulose such as vinylidene chloride resin, polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol resin, polyurethane resin, polyacrylic resin, polyacrylamide resin, polyvinylpyrrolidone resin, polyvinylpyridine resin, water-soluble polyester resin, nitrocellulose Ester resin, cellulose ether resin, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, zirconium chelate compound, zirconium al Kishido compounds such as organic zirconium compounds of titanyl chelate compounds, organic titanyl compounds such as titanium alkoxide compound, a known binder resin such as a silane coupling agent and the like. These may be used alone or in combination of two or more in any combination and ratio. Moreover, you may use with the hardening | curing form with the hardening | curing agent. Among these, alcohol-soluble copolymerized polyamides, modified polyamides, and the like are preferable because they exhibit good dispersibility and coatability.

The use ratio of the inorganic particles to the binder resin used in the undercoat layer can be arbitrarily selected, but is usually 10% by mass with respect to the binder resin from the viewpoint of the stability of the dispersion and the coating property. As mentioned above, it is preferable to use in the range of 500 mass% or less.
The thickness of the undercoat layer is arbitrary as long as the effects of the present invention are not significantly impaired, but the viewpoint of improving the electrical characteristics, strong exposure characteristics, image characteristics, repeat characteristics, and coating properties during production of the electrophotographic photosensitive member. Therefore, it is usually 0.01 μm or more, preferably 0.1 μm or more, and usually 30 μm or less, preferably 20 μm or less. A known antioxidant or the like may be mixed in the undercoat layer. For the purpose of preventing image defects, pigment particles, resin particles and the like may be included.

<Photosensitive layer>
The photosensitive layer is formed on the above-mentioned conductive support (or on the undercoat layer when the above-described undercoat layer is provided). As a type of the photosensitive layer, a charge generation material and a charge transport material (including the charge transport material of the present invention) are present in the same layer and have a single layer structure in which they are dispersed in a binder resin (hereinafter, as appropriate, A single-layer photosensitive layer), a charge generation layer in which a charge generation material is dispersed in a binder resin, and a charge transport material (including the charge transport material of the present invention) are dispersed in the binder resin. In addition, a function-separated type having a laminated structure composed of two or more layers including a charge transport layer (hereinafter, referred to as “laminated photosensitive layer” as appropriate) may be mentioned.
In addition, as the laminated photosensitive layer, a charge-generating layer and a charge transport layer are laminated in this order from the conductive support side, and conversely, a charge transport layer and a charge generation layer are formed from the conductive support side. There are reverse laminated photosensitive layers provided in order, and any of them can be adopted, but a forward laminated photosensitive layer capable of exhibiting balanced photoconductivity is particularly preferable.

<Laminated photosensitive layer>
[Charge generation layer]
The charge generation layer of the laminated photosensitive layer (function-separated type photosensitive layer) contains a charge generation material, and usually contains a binder resin and other components used as necessary. Such a charge generation layer is prepared by, for example, preparing a coating solution by dissolving or dispersing a charge generation material and a binder resin in a solvent or a dispersion medium. (In the case where an undercoat layer is provided, on the undercoat layer), and in the case of a reverse laminated type photosensitive layer, it can be applied and dried on a charge transport layer.

  Examples of the charge generation material include inorganic photoconductive materials such as selenium and its alloys, cadmium sulfide, and organic photoconductive materials such as organic pigments. Organic photoconductive materials are preferred, and organic photoconductive materials are particularly preferable. Pigments are preferred. Examples of organic pigments include phthalocyanine pigments, azo pigments, dithioketopyrrolopyrrole pigments, squalene (squarylium) pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments, and benzimidazole pigments. . Among these, phthalocyanine pigments or azo pigments are particularly preferable. When organic pigments are used as the charge generating substance, usually, fine particles of these organic pigments are used in the form of a dispersion layer bound with various binder resins.

  When using a phthalocyanine pigment as a charge generating material, specifically, metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, aluminum or other metal or oxide thereof, halide, Those having each crystal form of coordinated phthalocyanines such as hydroxides and alkoxides, and phthalocyanine dimers using oxygen atoms as bridging atoms are used. In particular, titanyl phthalocyanines (also known as oxytitanium) such as X-type, τ-type metal-free phthalocyanine, A-type (also known as β-type), B-type (also known as α-type), D-type (also known as Y-type), which are highly sensitive crystal types Phthalocyanine), vanadyl phthalocyanine, chloroindium phthalocyanine, hydroxyindium phthalocyanine, chlorogallium phthalocyanine such as type II, hydroxygallium phthalocyanine such as type V, μ-oxo-gallium phthalocyanine dimer such as type G and type I, type II, etc. The [mu] -oxo-aluminum phthalocyanine dimer is preferred.

  Among these phthalocyanines, A-type (also known as β-type), B-type (also known as α-type), and powder X-ray diffraction angle 2θ (± 0.2 °) are 27.1 ° or 27.3 °. D-type (Y-type) titanyl phthalocyanine, II-type chlorogallium phthalocyanine, V-type hydroxygallium phthalocyanine, hydroxygallium phthalocyanine having the strongest peak at 28.1 °, or 26. Hydroxygallium phthalocyanine having no peak at 2 °, a clear peak at 28.1 °, and a full width at half maximum W of 25.9 ° of 0.1 ° ≦ W ≦ 0.4 ° G-type μ-oxo-gallium phthalocyanine dimer and the like are particularly preferable.

  The oxytitanium phthalocyanine crystal is preferably a crystal having main diffraction peaks at Bragg angles (2θ ± 0.2 °), 24.1 °, and 27.2 ° with respect to CuKα characteristic X-rays (wavelength 1.541Å). As another diffraction peak, a crystal having a peak near 26.2 ° is inferior in crystal stability at the time of dispersion, and therefore it is preferable that no peak is present near 26.2 °. Among them, 7.3 °, 9.6 °, 11.6 °, 14.2 °, 18.0 °, 24.1 ° and 27.2 °, or 7.3 °, 9.5 °, 9 Dark decay and residual potential when crystals having main diffraction peaks at 0.7 °, 11.6 °, 14.2 °, 18.0 °, 24.2 ° and 27.2 ° are used as electrophotographic photoreceptors. From the viewpoint of

  When a metal-free phthalocyanine compound or a metal-containing phthalocyanine compound is used as the charge generation material, a highly sensitive photoreceptor can be obtained with respect to a laser beam having a relatively long wavelength, for example, a laser beam having a wavelength around 780 nm. Further, when an azo pigment such as monoazo, diazo, or trisazo is used, white light, laser light having a wavelength around 660 nm, or laser light having a relatively short wavelength (for example, a wavelength in the range of 380 nm to 500 nm). It is possible to obtain a photoreceptor having sufficient sensitivity to the laser beam).

  The phthalocyanine compound may be a single compound or several mixed or mixed crystal states. As the mixed state in the phthalocyanine compound or crystal state here, those obtained by mixing the respective constituent elements later may be used, or the mixed state in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, crystallization, etc. It may be the one that gave rise to. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are known. In order to generate a mixed crystal state, as described in JP-A-10-48859, two types of crystals are mixed, mechanically ground and made amorphous, and then converted into a specific crystal state by solvent treatment. The method of doing is mentioned.

On the other hand, when an azo pigment is used as a charge generation material, various known azo pigments can be used as long as they have sensitivity to a light source for light input. Trisazo pigments are preferably used.
When the organic pigments exemplified above are used as the charge generation material, one kind may be used alone, or two or more kinds of pigments may be mixed and used. In this case, it is preferable to use a combination of two or more kinds of charge generating materials having spectral sensitivity characteristics in different spectral regions of the visible region and the near red region. Among them, a disazo pigment, a trisazo pigment and a phthalocyanine pigment are preferably used in combination. More preferred.

The binder resin used for the charge generation layer constituting the multilayer photosensitive layer is not particularly limited. For example, polyvinyl butyral resin, polyvinyl formal resin, partially acetalized polyvinyl butyral in which part of butyral is modified with formal, acetal, or the like. Polyvinyl acetal resin such as resin, polyarylate resin, polycarbonate resin, polyester resin, modified ether polyester resin, phenoxy resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, polystyrene resin, acrylic resin, methacrylic resin ,
Polyacrylamide resin, polyamide resin, polyvinyl pyridine resin, cellulose resin, polyurethane resin, epoxy resin, silicone resin, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, casein, vinyl chloride-vinyl acetate copolymer, hydroxy-modified vinyl chloride-acetic acid Vinyl copolymers, carboxyl-modified vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate copolymers such as vinyl chloride-vinyl acetate-maleic anhydride copolymers, styrene-butadiene copolymers, vinylidene chloride- Insulating resins such as acrylonitrile copolymer, styrene-alkyd resin, silicon-alkyd resin, phenol-formaldehyde resin, and organic photoconductive materials such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylperylene Rimmer, and the like. Any one of these binder resins may be used alone, or two or more kinds thereof may be mixed and used in any combination.

Specifically, the charge generation layer is prepared by dispersing a charge generation material in a solution in which the above-described binder resin is dissolved in an organic solvent to prepare a coating solution, which is provided on a conductive support (providing an undercoat layer). In some cases, it is formed by coating (on the undercoat layer).
The solvent used for the preparation of the coating solution is not particularly limited as long as it can dissolve the binder resin, but examples thereof include saturated aliphatic solvents such as pentane, hexane, octane, and nonane, toluene, xylene, anisole, and the like. Aromatic solvents, halogenated aromatic solvents such as chlorobenzene, dichlorobenzene, chloronaphthalene, amide solvents such as dimethylformamide, N-methyl-2-pyrrolidone, methanol, ethanol, isopropanol, n-butanol, benzyl alcohol, etc. Alcohol solvents, aliphatic polyhydric alcohols such as glycerin and polyethylene glycol, chain or cyclic ketone solvents such as acetone, cyclohexanone, methyl ethyl ketone, 4-methoxy-4-methyl-2-pentanone, methyl formate, ethyl acetate , N-butyl acetate, etc. Ester solvents, halogenated hydrocarbon solvents such as methylene chloride, chloroform, 1,2-dichloroethane, chain or cyclic such as diethyl ether, dimethoxyethane, tetrahydrofuran, 1,4-dioxane, methyl cellosolve, ethyl cellosolve Ether solvents, acetonitrile, dimethyl sulfoxide, sulfolane, aprotic polar solvents such as hexamethylphosphate triamide, n-butylamine, isopropanolamine, diethylamine, triethanolamine, nitrogen-containing compounds such as ethylenediamine, triethylenediamine, triethylamine, ligroin Mineral oil, water, etc. are mentioned. Any one of these may be used alone, or two or more of these may be used in combination. In addition, when providing the above-mentioned undercoat layer, what does not melt | dissolve this undercoat layer is preferable.

  In the charge generation layer, the compounding ratio (mass ratio) of the binder resin and the charge generation substance is usually 10 parts by mass or more, preferably 30 parts by mass or more, with respect to 100 parts by mass of the binder resin. Usually, it is 1000 mass parts or less, Preferably it is the range of 500 mass parts or less. The thickness of the charge generation layer is usually 0.1 μm or more, preferably 0.15 μm or more, and usually 10 μm or less, preferably 0.6 μm or less. If the ratio of the charge generation material is too high, the stability of the coating solution may be reduced due to aggregation of the charge generation material. On the other hand, if the ratio of the charge generating substance is too low, the sensitivity as a photoreceptor may be reduced.

  As a method for dispersing the charge generation material, a known dispersion method such as a ball mill dispersion method, an attritor dispersion method, or a sand mill dispersion method can be used. At this time, it is effective to refine the particles to a particle size in the range of 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less.

[Charge transport layer]
The charge transport layer of the multilayer photoreceptor contains the above-described charge transport material and binder resin, and other components used as necessary. Specifically, such a charge transport layer is prepared by dissolving or dispersing a charge transport material or the like and a binder resin in a solvent to prepare a coating solution. In addition, in the case of a reverse lamination type photosensitive layer, it can be obtained by coating and drying on a conductive support (or on the undercoat layer when an undercoat layer is provided).

  As the charge transport material, in addition to the charge transport material represented by the above formula (1), other known charge transport materials may be used in combination. When other charge transport materials are used in combination, the type is not particularly limited, but for example, carbazole derivatives, hydrazone compounds, aromatic amine derivatives, enamine derivatives, butadiene derivatives and those in which a plurality of these derivatives are bonded are preferable. Any of these charge transport materials may be used alone, or a plurality of types may be used in any combination.

  The binder resin is not limited as long as the viscosity average molecular weight is from 40,000 to 100,000, but butadiene resin, styrene resin, vinyl acetate resin, vinyl chloride resin, acrylic ester resin, methacrylic ester resin, vinyl alcohol resin, ethyl Polymers and copolymers of vinyl compounds such as vinyl ether, polyvinyl butyral resin, polyvinyl formal resin, partially modified polyvinyl acetal, polyamide resin, polyurethane resin, cellulose ester resin, phenoxy resin, silicone resin, silicone-alkyd resin, poly-N -Vinyl carbazole resin, polycarbonate resin, and polyester resin are preferably used. Of these, polycarbonate resins and polyester resins are preferred. Polyarylate resins, which are names for polyester resins, especially wholly aromatic polyester resins, can increase the elastic deformation rate, and are particularly preferable from the viewpoint of mechanical properties such as wear resistance, scratch resistance, and filming resistance. In general, a polyester resin is superior to a polycarbonate resin from the viewpoint of mechanical properties, but is inferior to a polycarbonate resin from the viewpoint of electrical characteristics and light fatigue. This is thought to be due to the fact that the ester bond is more polar than the carbonate bond and has a strong acceptor property. In addition, these resins may be used as a mixture of two or more kinds within a range that does not impair the function.

First, the polyester resin will be described. Generally, a polyester resin is obtained by polycondensing a polyhydric alcohol component and a polyvalent carboxylic acid component such as a carboxylic acid, a carboxylic acid anhydride, or a carboxylic acid ester as a raw material monomer.
As the polyhydric alcohol component, polyoxypropylene (2.2) -2,2-bis (4
-Hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis (
4-Hydroxyphenyl) propane and other bisphenol A alkylene (2 to 3 carbon atoms) oxide (average added mole number 1 to 10) adduct, ethylene glycol, propylene glycol, neopentyl glycol, glycerin, pentaerythritol, trimethylolpropane , Hydrogenated bisphenol A, sorbitol, or alkylene thereof (2 carbon atoms)
-3) Oxide (average added mole number 1 to 10) adduct, aromatic bisphenol and the like, and those containing one or more of these are preferable.

The polyvalent carboxylic acid component includes dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, fumaric acid and maleic acid, carbon numbers such as dodecenyl succinic acid and octyl succinic acid.
Succinic acid, trimellitic acid, pyromellitic acid, anhydrides of these acids and alkyl (1 to 3 carbon atoms) esters of these acids substituted with -20 alkyl groups or C2-C20 alkenyl groups The thing containing 1 or more types of these is preferable.
Among these polyester resins, preferred is a wholly aromatic polyester resin (polyarylate resin) having a structural unit represented by the following formula (4).

In formula (4), Ar ^{13 to} Ar ¹⁶ each independently represent an arylene group which may have a substituent, and X represents a single bond, an oxygen atom, a sulfur atom, or an alkylene group. s is 0 or more and 2
Represents the following integers: Y represents a single bond, an oxygen atom, a sulfur atom, or an alkylene group. In the above formula (4), Ar ^{13 to} Ar ¹⁶ each independently represent an arylene group that may have a substituent. As carbon number which an arylene group has, it is 6 or more normally, and the upper limit is 20 or less normally, Preferably it is 10 or less, More preferably, it is 6. If the number of carbon atoms is too large, the production cost increases and the electrical characteristics may deteriorate.

Specific examples of Ar ^{13 to} Ar ¹⁶ include 1,2-phenylene group, 1,3-phenylene group, 1,4-phenylene group, naphthylene group, anthrylene group, phenanthrylene group and the like. Among these, the arylene group is preferably a 1,4-phenylene group from the viewpoint of electrical characteristics. An arylene group may be used individually by 1 type, and may be used 2 or more types by arbitrary ratios and combinations.

Moreover, as a substituent which Ar < ¹³ > -Ar < ¹⁶ > may have, an alkyl group, an aryl group, a halogen group, an alkoxy group, etc. are mentioned. Among these, the alkyl group is preferably a methyl group, an ethyl group, a propyl group, or an isopropyl group, considering the mechanical properties of the binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer. As a halogen group, a fluorine atom, a chlorine atom, a bromine atom and an iodine atom are preferable, and as an alkoxy group, a methoxy group, an ethoxy group, a propoxy group and a butoxy group are preferable. In addition, when a substituent is an alkyl group, carbon number of the alkyl group is usually 1 or more, and usually 10 or less, preferably 8 or less, more preferably 2 or less.

More specifically, Ar ¹⁵ and Ar ¹⁶ each independently preferably has 0 or more and 2 or less substituents, more preferably have a substituent from the viewpoint of adhesiveness, and among them, substitution from the viewpoint of wear resistance. It is particularly preferable that the number of groups is one. Moreover, as a substituent, an alkyl group is preferable and a methyl group is particularly preferable.
On the other hand, Ar ¹³ and Ar ¹⁴ each independently preferably has 0 or more and 2 or less substituents, and more preferably has no substituent from the viewpoint of wear resistance.

In the above formula (4), Y is a single bond, an oxygen atom, a sulfur atom, or an alkylene group. As the alkylene group, —CH ₂ —, —CH (CH ₃ ) —, —C (CH ₃ ) ₂ —, and cyclohexylene are preferable, and —CH ₂ —, —CH (CH ₃ ) —, — are more preferable. C (CH ₃ ) ₂ — and cyclohexylene are preferable, and —CH ₂ — and —CH (CH ₃ ) — are particularly preferable.

In the above formula (4), X is a single bond, an oxygen atom, a sulfur atom, or an alkylene group, and among them, X is preferably an oxygen atom. In this case, s is particularly preferably 1.
Specific examples of preferred dicarboxylic acid residues when s is 1 include diphenyl ether-2,2′-dicarboxylic acid residues, diphenyl ether-2,3′-dicarboxylic acid residues, and diphenyl ether-2,4′-dicarboxylic acid. Residue, diphenyl ether-3,3'-dicarboxylic acid residue, diphenyl ether-3,4'-dicarboxylic acid residue, diphenyl ether-4,4 '
-Dicarboxylic acid residue etc. are mentioned. Among these, considering the simplicity of production of the dicarboxylic acid component, diphenyl ether-2,2′-dicarboxylic acid residue, diphenyl ether-2,4′-dicarboxylic acid residue, diphenyl ether-4,4′-dicarboxylic acid Residues are more preferred, and diphenyl ether-4,4′-dicarboxylic acid residues are particularly preferred.

Specific examples of the dicarboxylic acid residue when s is 0 include phthalic acid residue, isophthalic acid residue, terephthalic acid residue, toluene-2,5-dicarboxylic acid residue, p-xylene-2,5- Dicarboxylic acid residue, naphthalene-1,4-dicarboxylic acid residue, naphthalene-2,3-dicarboxylic acid residue, naphthalene-2,6-dicarboxylic acid residue, biphenyl-2,2′-dicarboxylic acid residue, Biphenyl-4,4′-dicarboxylic acid residue may be mentioned, preferably phthalic acid residue, isophthalic acid residue, terephthalic acid residue, naphthalene-1,4-dicarboxylic acid residue, naphthalene-2,6- Dicarboxylic acid residues, biphenyl-2,2′-dicarboxylic acid residues, biphenyl-4,4′-dicarboxylic acid residues, particularly preferably isophthalic acid residues and terephthalic acid residues. It is also possible to use a combination of a plurality of rubonic acid residues. The ratio of isophthalic acid residue to terephthalic acid residue is usually 50:50, but can be arbitrarily changed. In that case, the higher the ratio of terephthalic acid residues, the better from the viewpoint of electrical characteristics.

Next, the polycarbonate resin will be described. Polycarbonate resin is produced by a solvent method such as interfacial method (interfacial polycondensation method) or solution method in which bisphenols and phosgene are reacted in solution, and polycondensation of bisphenol and carbonic acid diester by transesterification. The thing by the melting method to make it react is known.
Of these, polycarbonate resin produced by the interfacial method is widely used for electrophotographic photoreceptors because it can be made high molecular weight, purified by liquid-liquid washing, and applicable to various types of bisphenol. It has been. On the other hand, for polycarbonate resin by the melt method, there are restrictions on the types of bisphenol that can be polymerized, it is difficult to increase the molecular weight, and it is difficult to remove impurities by washing, but because phosgene is not used in the polymerization process, it is a safety issue. There is merit in.
Preferred examples of bisphenol are shown below.

  The viscosity average molecular weight of the binder resin used in the present invention is 40,000 or more, preferably 50,000 or more, more preferably 60,000 or more from the viewpoint of mechanical strength. Further, from the viewpoint of productivity such as the dispersibility of the compound and the viscosity of the coating solution, it is 100,000 or less, preferably 95,000 or less, more preferably 90,000 or less. In addition, a viscosity average molecular weight can be measured by the method as described in an Example using an Ubbelohde type capillary viscometer etc., for example.

The thickness of the charge transport layer is not particularly limited, but is usually 5 μm or more, preferably 10 μm or more, on the other hand, usually 40 μm or less, preferably 35 μm or less, from the viewpoints of long life, image stability, and charging stability. Furthermore, in the range of 30 μm or less, 25 μm or less is particularly preferably used from the viewpoint of high resolution.
<Single layer type photosensitive layer>
The single-layer type photosensitive layer is formed using a charge generation material, a charge transport material represented by the formula (1), and the binder resin. Specifically, a charge generation material, a charge transport material, and various binder resins are dissolved or dispersed in a solvent to prepare a coating solution, and on a conductive support (if an undercoat layer is provided, on the undercoat layer) It can be obtained by coating and drying.

The charge transport material represented by the formula (1), the kind of the binder resin, and the use ratio thereof are the same as those in the charge transport layer of the multilayer photoreceptor.
As the charge generation material, the same materials as those described for the charge generation layer of the multilayer photoreceptor can be used. However, in the case of a photosensitive layer of a single layer type photoreceptor, it is necessary to sufficiently reduce the particle size of the charge generating material. Specifically, the range is usually 1 μm or less, preferably 0.5 μm or less.

In addition, the usage ratio of the binder resin and the charge generating substance in the single-layer type photosensitive layer is usually 0.1 parts by mass or more, preferably 1 part by mass or more, with respect to 100 parts by mass of the binder resin. The range is usually 30 parts by mass or less, preferably 10 parts by mass or less.
The film thickness of the single-layer type photosensitive layer is usually 10 μm or more, preferably 15 μm or more, and usually 50 μm or less, preferably 40 μm or less.

<Other additives>
For the purpose of improving film-forming properties, flexibility, coating properties, stain resistance, gas resistance, light resistance, etc., in both the photosensitive layer and each layer constituting it, both in the multilayer type photosensitive member and the single layer type photosensitive member. Additives such as well-known antioxidants, plasticizers, ultraviolet absorbers, electron-withdrawing compounds, leveling agents, and visible light shielding agents may be included.

<Other functional layers>
Further, in both the laminated type photoreceptor and the single layer type photoreceptor, the photosensitive layer formed by the above procedure may be the uppermost layer, that is, the surface layer, but another layer may be provided on the photosensitive layer and used as the surface layer. Good. For example, a protective layer may be provided for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the deterioration of the photosensitive layer due to discharge products generated from a charger or the like.
Further, for the purpose of reducing the frictional resistance and wear on the surface of the photoconductor, and increasing the transfer efficiency of the toner from the photoconductor to the transfer belt and paper, etc., the surface layer is made of fluorine resin, silicon resin, polyethylene resin, or the like. You may contain the particle | grains which consist of these resin, and the particle | grains of inorganic compounds, such as a silica and an alumina.

<Method for forming photosensitive layer>
The photosensitive layer constituting the photosensitive member is formed by dip coating, spray coating, nozzle coating, bar coating, roll coating, blade coating on a conductive support obtained by dissolving or dispersing a substance to be contained in a solvent. It is formed by repeating a coating / drying step sequentially for each layer by a known method such as.

  The solvent or dispersion medium used for preparing the coating solution contains an ether solvent. Specific examples include aliphatic cyclic ethers such as tetrahydrofuran, methyltetrahydrofuran, tetrahydropyran, 1,4-dioxane, and 1,3-dioxolane, fats such as ethylpropyl ether, propyl ether, dibutyl ether, dimethoxyethane, and diethoxyethane. Aromatic ethers such as aromatic chain ethers, anisole, methoxytoluene, phenetole and the like are mentioned. From the viewpoint of film-forming properties of the photosensitive layer, aliphatic cyclic ethers and aromatic ethers are preferable, and from the viewpoint of repeated transfer voltage resistance, tetrahydrofuran 1,3-dioxolane and anisole are more preferable.

Solvents that may be used together with ether solvents include alcohols such as methanol, ethanol, propanol and 2-methoxyethanol, esters such as methyl formate and ethyl acetate, acetone, methyl ethyl ketone, cyclohexanone and 4-methoxy-4-methyl. Ketones such as 2-pentanone, aromatic hydrocarbons such as benzene, toluene, xylene, dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane , Chlorinated hydrocarbons such as 1,2-dichloropropane and trichloroethylene, nitrogen-containing compounds such as n-butylamine, isopropanolamine, diethylamine, triethanolamine, ethylenediamine and triethylenediamine, acetonitrile N- methylpyrrolidone, N, N- dimethylformamide, aprotic polar solvents such as dimethyl sulfoxide and the like. In view of the influence on the environment, a non-halogen solvent is preferable. Moreover, you may use 2 or more types together by arbitrary combinations and kinds. Among these, aromatic hydrocarbons are preferable from the viewpoint of compatibility with ether solvents, and toluene is particularly preferable.

When used as a mixed solvent, the mass ratio [ether solvent / other solvent] is usually 1/2 or more, preferably 1/1 or more, more preferably 2/1 or more, from the viewpoint of repeated transfer voltage resistance. is there. From the viewpoint of applicability, it is usually 15/1 or less, preferably 10/1 or less.
It is preferable to adjust the coating solution for forming the photosensitive layer so that the mass ratio of the charge transport material to the solvent [charge transport material / solvent] is 1/10 to 1/100. From the viewpoint of solubility with the charge transport material, it is preferably 1/12 or less, and more preferably 1/15 or less. From the viewpoint of applicability, 1/90 or more is more preferable, and 1/50 or more is even more preferable.

  In the obtained photosensitive layer, the solvent usually used in the coating solution remains. A halogen-based solvent having a halogen atom such as chlorine in the structure generates free halogen when the solvent itself decomposes during production of the photoreceptor and during long-term storage, causing deterioration of the characteristics of the electrophotographic photoreceptor. In view of the possibility, it is preferably 1.0 mg / g or less, more preferably not remaining in the photosensitive layer. In the case of a non-halogen solvent having no halogen atom in the structure, it is usually 20.0 mg / g or less, more preferably 15.0 mg / g or less, and even more preferably 12.5 mg / g or less in the photosensitive layer. Yes, usually 0.05 mg / g or more, more preferably 0.1 mg / g or more, still more preferably 0.5 mg / g or more, still more preferably 1.0 mg / g or more. If the remaining amount in the photosensitive layer is too large, the mechanical strength of the photosensitive member may be insufficient, and if it is too small, the load during drying of the photosensitive layer in the production of the photosensitive member may be too high and the productivity may decrease. There is.

When mixing the charge transport material and the solvent, it is preferable to dissolve by heating. The temperature of the solution at the time of heating is usually 20 ° C. or higher, preferably 25 ° C. or higher, more preferably 30 ° C. or higher, from the viewpoint of solubility. From the viewpoint of preventing decomposition, it is usually 80 degrees or less, preferably 70 degrees or less, more preferably 65 degrees or less.
For example, in the case of a charge transport layer of a single layer type photoreceptor or a function separation type photoreceptor, the solid content concentration of the coating solution is usually 5% by mass or more, preferably 10% by mass or more, and usually 40% by mass or less. The range is preferably 35% by mass or less. In addition, the viscosity of the coating solution is usually 10 mPa · s or higher, preferably 50 mPa · s or higher, and usually 1500 mPa · s or lower, preferably 1000 mPa · s or lower, at the temperature during use.

  In the case of a charge generation layer of a multilayer photoreceptor, the solid content concentration of the coating solution is usually 0.1% by mass or more, preferably 1% by mass or more, and usually 15% by mass or less, preferably 10% by mass. % Or less. In addition, the viscosity of the coating solution is usually 0.01 mPa · s or higher, preferably 0.1 mPa · s or higher, and usually 20 mPa · s or lower, preferably 10 mPa · s or lower, at the temperature during use.

Examples of the coating method include a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method, an air knife coating method, and a curtain coating method. Other known coating methods can also be used.
The coating solution is preferably dried by touching at room temperature, followed by heating or drying in a temperature range of usually 30 ° C. or more and 200 ° C. or less for 1 minute to 2 hours, while still or blowing. Further, the heating temperature may be constant, or heating may be performed while changing the temperature during drying.

≪Image forming device≫
Next, a drum cartridge and an image forming apparatus using the electrophotographic photosensitive member of the present invention will be described with reference to FIG.
In FIG. 1, reference numeral 1 denotes a drum-shaped photoconductor, which is rotationally driven at a predetermined peripheral speed in the direction of an arrow. The photosensitive member 1 is uniformly charged at a predetermined positive or negative potential on the surface by the charging unit 2 during the rotation process, and then exposure for forming a latent image is performed by the image exposure unit in the exposure unit 3.

  The formed electrostatic latent image is then developed with toner by the developing means 4, and the toner developed image is sequentially transferred onto the transfer body (paper or the like) P fed from the paper feeding unit by the corona transfer means 5. . In FIG. 1, the developing unit 4 includes a developing tank 41, an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45, and has a configuration in which toner T is stored inside the developing tank 41. . Further, a replenishing device (not shown) for replenishing the toner T may be attached to the developing unit 4 as necessary. The replenishing device is configured to be able to replenish toner T from a container such as a bottle or a cartridge.

  The image-transferred transfer body is then sent to the fixing means 7 where the image is fixed and printed out of the apparatus. The fixing unit 7 includes an upper fixing member (fixing roller) 71 and a lower fixing member (fixing roller) 72, and a heating device 73 is provided inside the fixing member 71 or 72. FIG. 1 shows an example in which a heating device 73 is provided inside the upper fixing member 71. The upper and lower fixing members 71 and 72 include a fixing roll in which a metal base tube made of stainless steel, aluminum or the like is coated with silicon rubber, a fixing roll in which Teflon (registered trademark) resin is coated, a fixing sheet, or the like. A member can be used. Further, the fixing members 71 and 72 may be configured to supply a release agent such as silicone oil in order to improve the releasability, or may be configured to forcibly apply pressure to each other by a spring or the like.

  When the toner transferred onto the recording paper P passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the toner is heated to a molten state and cooled after passing through the recording paper. Toner is fixed on P. The surface of the photoreceptor 1 after the image transfer is cleaned by the cleaning unit 6 to remove the transfer residual toner, and is neutralized by the neutralization unit for the next image formation.

  In using the electrophotographic photosensitive member of the present invention, as a charger, in addition to a corona charger such as corotron or scorotron, a direct charging means for charging a charged member by contacting a directly charged member to which a voltage is applied is provided. It may be used. Examples of direct charging means include contact chargers such as charging rollers and charging brushes. As the direct charging means, any one that involves air discharge or injection charging that does not involve air discharge is possible. Moreover, as a voltage applied at the time of charging, it is possible to use only a direct current voltage or to superimpose an alternating current on a direct current.

For the exposure, a halogen lamp, a fluorescent lamp, a laser (semiconductor, He—Ne), LED, a photoreceptor internal exposure system, or the like is used. As the digital electrophotographic system, it is preferable to use a laser, LED, optical shutter array, or the like. . As the wavelength, in addition to 780 nm monochromatic light, it is possible to use monochromatic light in the 600 to 700 nm region and slightly shorter wavelength.
In the development process, a dry development method such as cascade development, one-component insulating toner development, one-component conductive toner development, two-component magnetic brush development, or the like is used.

  As the toner, in addition to the pulverized toner, chemical toners such as suspension granulation, suspension polymerization, and emulsion polymerization aggregation can be used. In particular, in the case of chemical toners, those having a small particle diameter of about 4 to 8 μm are used, and those having a shape close to a sphere, and those outside a potato-like sphere can also be used. The polymerized toner is excellent in charging uniformity and transferability, and is preferably used for high image quality.

For the transfer process, electrostatic transfer methods such as corona transfer, roller transfer, and belt transfer, pressure transfer methods, and adhesive transfer methods are used. For fixing, heat roller fixing, flash fixing, oven fixing, pressure fixing, IH fixing, belt fixing, IHF fixing, etc. may be used. These fixing methods may be used alone or in combination with a plurality of fixing methods. May be.
For cleaning, brush cleaner, magnetic brush cleaner, electrostatic brush cleaner, magnetic roller cleaner, blade cleaner, etc. are used.

In many cases, the static elimination step is omitted, but when used, a fluorescent lamp, LED, or the like is used, and an exposure energy that is three times or more of the exposure light is often used as the intensity. In addition to these processes, a pre-exposure process and an auxiliary charging process may be included.
A cartridge using the electrophotographic photosensitive member according to the present invention includes the photosensitive member 1 and at least one portion of the group consisting of the charging unit 2, the exposure unit 3, the developing unit 4, and the cleaning unit 6. Good.

  In the present invention, a plurality of components such as the drum-shaped photosensitive member 1, the charging unit 2, the developing unit 4 and the cleaning unit 6 are integrally combined as a drum cartridge, and the drum cartridge is copied. It may be configured to be detachable from the main body of an electrophotographic apparatus such as a machine or a laser beam printer. For example, at least one of the charging unit 2, the developing unit 4, and the cleaning unit 6 can be integrally supported together with the drum-shaped photoreceptor 1 to form a cartridge.

The present invention can also be applied to an image forming apparatus including the electrophotographic photosensitive member, the charging unit 2, the exposure unit 3, the developing unit 4, and the cleaning unit 6 according to the present invention.
FIG. 2 is a schematic diagram of the main components of the full-color tandem system. The photosensitive member 1, the charging device 2, the exposure device 3, the black developing device 4k, the cyan developing device 4c, the yellow developing device 4y, the magenta developing device 4m, and the transfer device 5. And a fixing device 7, and the cleaning device is omitted here. A color image can be obtained by adjusting magenta, yellow, cyan, and black toners in multiple layers to a desired color.

  In the case of the tandem method, the color development part located before the black development part may reduce color mixing due to reverse transfer of black toner, and the black development part located behind the color development part is only black. In the case of forming an image with a single color, it is preferable that the color mixture due to the photosensitive member fog of the color toner is reduced, and the speed of black image formation can be increased by transporting the recording paper by short-passing the color developing unit. .

  When applied to full-color image formation, such a cyan, magenta, and yellow color development unit is suitable for a tandem system in which the black development unit is located after the color development unit. It should be noted that the order in which the cyan, magenta, and yellow color developing units are positioned can be freely changed in a timely manner.

  Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples. However, the following examples are given in order to explain the present invention in detail, and the present invention is not limited to the examples shown below without departing from the gist thereof, and can be arbitrarily modified and implemented. can do. In the following examples and comparative examples, “parts” indicates “parts by mass” or “parts by weight” unless otherwise specified. Further, the viscosity molecular weight of the binder resin used in this example and the purity of the charge transport material were measured under the following conditions.

<Measurement of viscosity average molecular weight of binder resin (Mv)>
Using an Ubbelohde capillary viscometer (dichloromethane flow time t0: 136.16 seconds), the flow time (t) of the binder resin dichloromethane solution (concentration: 6.00 g / L) was measured at 20.0 ° C. Based on the following formula, the viscosity average molecular weight (Mv) of the binder resin was calculated.
ηsp = (t / t0) −1
a = 0.438 × ηsp + 1
b = 100 × (ηsp / C)
C = 6.00 [g / L]
η = b / a
Mv = 3207 × η1.205

<Purity measurement of charge transport material>
Measurement was performed under the following conditions using a liquid chromatograph apparatus having a UV-vis detector.
Detection wavelength: 254 nm
Moving bed: Acetonitrile moving bed Flow rate: 1.0 ml / min
Column: GL Science Co., Ltd.
Inertsil ODS-3 (5 μm)
4.6mmφ * 150mm
Column temperature: 40 ° C
Analysis solution: injection of 1 μl of a tetrahydrofuran solution [5 mg / ml] of a charge transport material

[Example 1]
<Method for creating electrophotographic photoreceptor>
Using the conductive support on which an aluminum vapor deposition film (thickness 70 nm) is formed on the surface of a biaxially stretched polyethylene terephthalate resin film (thickness 75 μm), the following undercoat layer dispersion is applied on the vapor deposition layer of the support: The coating was applied by a bar coater so that the film thickness after drying was 1.25 μm or less, and dried to form an undercoat layer.

  High-speed fluidized mixing of rutile type titanium oxide having an average primary particle diameter of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by mass of methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) Disperse the surface-treated titanium oxide obtained by mixing in a kneading machine (“SMG300” manufactured by Kawata Co., Ltd.) and mixing at high speed at a rotational peripheral speed of 34.5 m / sec using a ball mill of methanol / 1-propanol. Thus, a dispersion slurry of hydrophobized titanium oxide was obtained. The dispersion slurry, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam [compound represented by the following formula (A)] / bis (4-amino-3-methylcyclohexyl) methane [the following formula ( Compound represented by B)] / hexamethylenediamine [compound represented by the following formula (C)] / decamethylene dicarboxylic acid [compound represented by the following formula (D)] / octadecamethylene dicarboxylic acid [following formula The compound represented by (E)] has a composition molar ratio of 75% / 9.5% / 3% / 9.5% / 3%, and is stirred and mixed while heating with the copolyamide pellets. After dissolving the polyamide pellets, by carrying out ultrasonic dispersion treatment, the mass ratio of methanol / 1-propanol / toluene is 7/1/2, and hydrophobically treated titanium oxide / copolymerized poly Containing bromide at a weight ratio 3/1 was undercoat layer dispersion having a solid concentration of 18.0%.

<Formation of charge generation layer>
As a charge generation material, oxytitanium phthalocyanine crystal (showing a main diffraction peak at 27.2 ° at a black angle (2θ ± 0.2 °) in an X-ray diffraction spectrum for CuKα characteristic X-ray) was used. Using 20 parts by mass of this oxytitanium phthalocyanine crystal, this was mixed with 280 parts by mass of 1,2-dimethoxyethane, pulverized with a sand grind mill for 2 hours, and subjected to atomization dispersion treatment to obtain a refined treatment liquid. Moreover, polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “Denkabutyral”) is added to a mixed solution of 253 parts by mass of 1,2-dimethoxyethane and 85 parts by mass of 4-methoxy-4-methyl-2-pentanone. 6000C) 10 parts by mass was dissolved to prepare a binder liquid.

  The charge generation layer coating solution was prepared by mixing the finely divided treatment liquid obtained by the fine particle dispersion treatment, the binder liquid, and 230 parts by mass of 1,2-dimethoxyethane. This charge generation layer coating solution is applied onto the undercoat layer on the conductive support by a bar coater so that the film thickness after drying is 0.4 μm and dried to form a charge generation layer. did.

<Formation of charge transport layer>
As the binder resin, a polyarylate resin (Mv = 72,000) having a structure of the following formula (PA) was used. Then, 40 parts by mass of a charge transport material having the structure of the following formula (CTM1) [synthesized by the method of Scheme 2 above (used in combination with a palladium compound and a ligand having a phosphorus atom as a catalyst) and then purified by an adsorbent. . Purity: 98.8%], 100 parts by mass of binder resin, 2 parts by mass of antioxidant having the structure of the following formula (AOX1), 0.1 part by mass of amine compound having the structure of the following formula (AOX2), and a leveling agent As a solution, 0.05 part by mass of silicone oil was dissolved in 910 parts by mass of a tetrahydrofuran / toluene (mass ratio 8/2) mixed solvent to prepare a coating solution for charge transport layer.

  The obtained coating solution for charge transport layer was applied onto the above-described charge generation layer so that the film thickness after drying was 18 μm, and Photoreceptor A having a laminated photosensitive layer was obtained.

[Example 2]
910 parts by mass of a tetrahydrofuran / toluene (mass ratio 8/2) mixed solvent in Example 1 <Method for producing electrophotographic photoreceptor> was changed to tetrahydrofuran / anisole (mass ratio 9/1).
Except having changed to 745 mass parts of mixed solvents, the photoreceptor B was manufactured by performing operation similar to Example 1. FIG.

[Example 3]
910 parts by mass of a mixed solvent of tetrahydrofuran / toluene (mass ratio 8/2) in Example 1 <Method for producing electrophotographic photosensitive member> is 805 masses of 1,3-dioxolane / anisole (mass ratio 9/1) mixed solvent. A photoconductor C was produced by carrying out the same operations as in Example 1 except that the parts were changed.

[Comparative Example 1]
The tetrahydrofuran / toluene (mass ratio 8/2) mixed solvent in Example 1 <Method for producing electrophotographic photosensitive member> was changed to dichloromethane used in Example 6 of JP-A No. 2000-162791. A comparative photoconductor A was produced by carrying out the same operations as in Example 1 except for the above.

[Comparative Example 2]
The tetrahydrofuran / toluene (mass ratio 8/2) mixed solvent in Example 1 <Method for producing electrophotographic photoreceptor> was changed to dichloroethane used in Example 19 of JP-A-9-292724. A comparative photoconductor B was manufactured by performing the same operation as in Example 1 except for the above.

<Evaluation of electrophotographic photoreceptor (initial & transfer memory evaluation)>
[Evaluation of initial electrical characteristics]
Using an electrophotographic characteristic evaluation apparatus (basic and applied electrophotographic technology, edited by Electrophotographic Society, Corona, pages 404-405) prepared in accordance with the electrophotographic society measurement standard, the photoconductor sheet is made of an aluminum drum. Attached to a cylindrical shape, the aluminum drum and the aluminum substrate of the photoconductor are connected to each other, and then the drum is rotated at a fixed number of revolutions, and the electrical property evaluation test is performed by a cycle of charging, exposure, potential measurement, and static elimination. Went. At that time, the initial surface potential was set to -700 V, monochromatic light of 660 nm was used for both exposure and charge removal, and the bright potential (Vr) when exposure light was irradiated at 5.0 μJ / cm 2 was measured. Further, the irradiation energy (half exposure energy: μJ / cm 2) when the surface potential is half of the initial surface potential (−350 V) is the sensitivity (E 1
/ 2) and measured. The smaller the absolute value of the value of Vr, the better the electrical characteristics, and the smaller the value of E1 / 2, the higher the sensitivity. The measurement environment was 25 ° C. and 50% relative humidity (N / N). The results are shown in Table-1.

[Transfer memory evaluation]
After the initial electrical property test was performed, a corotron to which +7.0 kV was applied between the potential measurement and the static elimination in the charging-exposure-potential measurement-static elimination cycle was installed in order to simulate the transfer load. In this state, a cycle of charging, exposure, potential measurement, transfer load, and static elimination was repeated 4000 times. At that time, the charging (scorotron charger) conditions were fixed so that the initial surface potential of the photoconductor was about −700 V at the beginning of 4000 times of repeated tests, and the difference (ΔV0) in the observed surface potential (V0) was measured. did. The smaller the absolute value of ΔV0, the better the chargeability during repeated use. The Vr was measured before and after 4000 repetition tests, and the difference (ΔVr) in the surface potential (Vr) after exposure with the initial value was obtained. The measurement environment was 25 ° C. and 50% RH. The results are shown in Table-2. The smaller the absolute values of ΔV0 and ΔVr, the smaller the potential fluctuation in repeated use, and the better the transfer memory.

[Example 4]
≪Creation of electrophotographic photoreceptor≫
<Manufacture of coating solution for forming charge generation layer>
As a charge generation material, oxytitanium phthalocyanine crystal (showing a main diffraction peak at 27.2 ° at a black angle (2θ ± 0.2 °) in an X-ray diffraction spectrum for CuKα characteristic X-ray) was used. Using 20 parts by weight of this oxytitanium phthalocyanine crystal, this was mixed with 280 parts by weight of 1,2-dimethoxyethane, pulverized with a sand grind mill for 1 hour, and subjected to atomization dispersion treatment to obtain a refining treatment liquid. In addition, a mixture of 253 parts by weight of 1,2-dimethoxyethane and 85 parts by weight of 4-methoxy-4-methyl-2-pentanone was added to polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “Denkabutyral” # 6000C) 20 parts by weight was dissolved to prepare a binder solution.
A charge generating layer coating liquid was prepared by mixing the above-described atomization treatment liquid obtained by the atomization dispersion treatment, the above-described binder liquid, and 230 parts by weight of 1,2-dimethoxyethane.

<Manufacture of coating liquid for charge transport layer formation>
100 parts by weight of a polyarylate resin (viscosity average molecular weight = 72,000) composed of repeating structural units of the above formula (resin PA), 40 parts by weight of a charge transport material having a structure represented by the following formula (CTM2), 4 parts by weight of an antioxidant represented by (AOX3), 0.5 part of a compound represented by the following formula (AOX4), 0.1 part of a compound represented by the above formula (AOX2), and a leveling agent 0.05 parts by weight of silicone oil was mixed with 1060 parts by weight of a mixed solvent of tetrahydrofuran and toluene (80% by weight of tetrahydrofuran, 20% by weight of toluene) to prepare a coating solution for forming a charge transport layer.

<Manufacture of photosensitive drum>
A cylinder made of an aluminum alloy having an outer diameter of 30 mm, a length of 246 mm, and a wall thickness of 0.75 mm, whose surface has been roughly cut, is subjected to anodizing treatment and then sealed with a sealing agent mainly composed of nickel acetate. As a result, an anodized film (alumite film) of about 6 μm was formed. The charge generation layer forming coating solution and the charge transport layer forming coating solution prepared in the coating liquid production example are sequentially applied to the obtained cylinder by a dip coating method and dried. A charge generation layer and a charge transport layer were formed so as to be 4 μm and 18 μm, and a photosensitive drum was manufactured. The charge transport layer was dried at 125 ° C. for 20 minutes. The charge transport layer of the obtained photoreceptor was peeled off, and the residual solvent was analyzed by gas chromatography [apparatus: 7890 manufactured by Agilent Technologies, Inc.]. As a result, the residual solvent amount in the photosensitive layer was a non-halogen solvent [tetrahydrofuran. And the total amount of toluene] was 9.5 mg / g, and no halogenated solvent was detected.

[Example 5]
Except that the ratio of the mixed solvent of tetrahydrofuran and toluene in <Manufacture of coating liquid for forming charge transport layer> was 90 wt% tetrahydrofuran and 10 wt% toluene, and the charge transport layer drying conditions were changed to 135 ° C for 30 minutes. A photoconductor was prepared by performing the same operation as in Example 4. Further, the charge transport layer of the obtained photoreceptor was peeled off, and the residual solvent was analyzed in the same manner as in Example 4. As a result, the amount of residual solvent in the photosensitive layer was 2 for the non-halogen solvent [total amount of tetrahydrofuran and toluene]. It was 2 mg / g, and no halogenated solvent was detected.

[Example 6]
<Manufacture of coating liquid for forming charge transport layer> In the same manner as in Example 4 except that a polyarylate resin composed of a repeating structural unit of the above formula (resin PA) was used having a viscosity average molecular weight of 53,000. A photoconductor was prepared by performing the operation. Further, the charge transport layer of the obtained photoreceptor was peeled off, and the residual solvent was analyzed in the same manner as in Example 4. As a result, the non-halogen solvent [total amount of tetrahydrofuran and toluene] was 10.1 mg / g. Solvent was not detected.

[Example 7]
A photoconductor was prepared by carrying out the same operations as in Example 6 except that the charge transport layer drying conditions in Example 4 were changed to 10 minutes at 120 degrees. Further, the charge transport layer of the obtained photoreceptor was peeled off and the residual solvent was analyzed in the same manner as in Example 4. As a result, the non-halogen solvent [total amount of tetrahydrofuran and toluene] was 17.5 mg / g, Solvent was not detected.

[Comparative Example 3]
<Manufacture of coating liquid for forming charge transport layer> In the same manner as in Example 4 except that a polyarylate resin comprising a repeating structural unit of the formula (resin PA) having a viscosity average molecular weight of 20,400 was used. A photoconductor was prepared by performing the operation. Further, the charge transport layer of the obtained photoreceptor was peeled, and the residual solvent was analyzed in the same manner as in Example 4. As a result, the non-halogen solvent [total amount of tetrahydrofuran and toluene] was 9.9 mg / g, Solvent was not detected.

[Comparative Example 4]
In <Manufacture of Coating Solution for Charge Transport Layer Formation>, a photoconductor was prepared by performing the same operation as in Example 4 except that the mixed solvent of tetrahydrofuran and toluene was changed to 1,2-dichloroethane. Further, the charge transport layer of the obtained photoreceptor was peeled off and the residual solvent was analyzed in the same manner as in Example 4. As a result, no non-halogen solvent was detected and the halogen solvent was 1.3 mg / g.

<Print life evaluation test>
The obtained photoreceptor was mounted on a drum cartridge of an A4 tandem type full-color printer [COREFIDO C711dn remodeling machine manufactured by Oki Data Co., Ltd. (printing speed: color 34 rpm, resolution: 600 dpi, exposure source: LED), and set in the printer.
The printer is placed in a low-temperature and low-humidity environment, and as a printing input, a vertically and horizontally symmetrical pattern consisting of a solid image and a line image with a printing rate of 5% is sent from the personal computer to the printer. 500 sheets were printed.

The thickness of the charge transport layer after printing was measured, and the printing durability was evaluated by comparing the thickness of the charge transport layer before and after printing.
A: The difference in thickness of the charge transport layer before and after printing is less than 2.0 μm. ○: The difference in the thickness of the charge transport layer before and after printing is 2.0 μm or more and less than 2.5 μm. Δ: The charge transport layer before and after printing. The film thickness difference of 2.5 μm or more and less than 3.0 μm ×: The film thickness difference of the charge transport layer before and after printing is 3.0 μm or more

<Evaluation of electrophotographic photoreceptor>
The obtained photoreceptor is mounted on an electrophotographic characteristic evaluation apparatus ("Basic and Application of Secondary Electrophotographic Technology" edited by Electrophotographic Society, Corona, page 404 to 405) prepared according to the standard of the Electrophotographic Society. Electrical characteristics were evaluated by carrying out a cycle of charging, exposure, potential measurement, and static elimination according to the following procedure.

  After charging so that the initial surface potential of the photoconductor becomes −700 V under the conditions of a temperature of 25 ° C. and a humidity of 50%, the light of the halogen lamp is converted to monochromatic light of 780 nm with an interference filter and irradiated with 0.6 μJ / cm 2. Table 3 shows the printing durability with the surface potential (unit: -V) measured after exposure with energy as the residual potential and the evaluation results of the electrophotographic photosensitive member characteristics (residual potential).

[Example 8]
<Manufacture of photosensitive drum>
A coating solution for forming an undercoat layer used in the production of the photoreceptor of Example 1 on an aluminum cylinder having an outer diameter of 30 mm, a length of 376 mm, and a wall thickness of 0.75 mm, the surface of which was roughly cut and finished, The coating solution for forming the charge generation layer and the coating solution for forming the charge transport layer are sequentially applied and dried by the dip coating method, and the coating is subtracted so that the film thicknesses after drying are 1.3 μm, 0.4 μm, and 18 μm, respectively. A photosensitive drum was manufactured by forming a layer, a charge generation layer, and a charge transport layer. The charge transport layer was dried at 125 ° C. for 20 minutes.

<Image test>
The image test is a dry development type electrophotographic system, a printing speed of 243 mm / s, a non-magnetic one-component development, a charging roller, a direct transfer method from a photoreceptor to a paper by a transport belt, and a tandem full color printer MICROLINE9800 manufactured by Oki Data. It was performed using. The test environment was 25 ° C. and 50% RH.

  The produced photosensitive drums (four equivalent products) were mounted on cyan, magenta, yellow, and black process cartridges, and 1000 sheets of A4 paper were printed in the vertical feed. Thereafter, the A4 paper was laterally fed to print the entire halftone image, but no image defects such as a density step at the edge were observed. In addition, halftone printing was performed by changing the test environment to 25 ° C. and 10% RH, but no decrease in density was observed.

[Example 9]
<Manufacture of photosensitive drum>
A photoconductor drum was manufactured in the same manner as in Example 4 except that the coating solution was changed to the coating solution used for manufacturing the photoconductor of Example 2.

<Image test>
In the same manner as in Example 4, the above photosensitive drums (four equivalent products) were mounted on process cartridges for each color of cyan, magenta, yellow, and black, and 1000 sheets of A4 paper were printed by vertical feeding. Thereafter, the A4 paper was laterally fed to print the entire halftone image, but no image defects such as a density step at the edge were observed. In addition, halftone printing was performed by changing the test environment to 25 ° C. and 10% RH, but no decrease in density was observed.

[Example 10]
<Manufacture of photosensitive drum>
A photoconductor drum was manufactured in the same manner as in Example 4 except that the coating solution was changed to the coating solution used for manufacturing the photoconductor of Example 3.

<Image test>
In the same manner as in Example 4, the above photosensitive drums (four equivalent products) were mounted on process cartridges for each color of cyan, magenta, yellow, and black, and 1000 sheets of A4 paper were printed by vertical feeding. Thereafter, the A4 paper was laterally fed to print the entire halftone image, but no image defects such as a density step at the edge were observed. In addition, halftone printing was performed by changing the test environment to 25 ° C. and 10% RH, but no decrease in density was observed.

1 Photoconductor (Electrophotographic photoconductor)
2 Charging device (charging roller; charging unit)
3 Exposure equipment (exposure section)
4 Development device (development unit)
DESCRIPTION OF SYMBOLS 5 Transfer apparatus 6 Cleaning apparatus 7 Fixing apparatus 41 Developing tank 42 Agitator 43 Supply roller 44 Developing roller 45 Control member 71 Upper fixing member (fixing roller)
72 Lower fixing member (fixing roller)
73 Heating device T Toner P Recording paper (paper, medium)

Claims (6)

In an electrophotographic photosensitive member having a photosensitive layer containing a charge transport material represented by formula (1) and a binder resin on a conductive support, the viscosity average molecular weight of the binder resin is from 40,000 to 10,000.
An electrophotographic photoreceptor, wherein the electrophotographic photoreceptor is 0 or less and the photosensitive layer contains an ether solvent.

(In the formula (1), ^Ar 1 ~Ar ⁵ is to display the independent the aryl group. However, the ants
Is a group selected from the group consisting of an alkyl group, an alkoxy group, and a halogen atom.
Both may be substituted with one kind. Ar ^{6 to} Ar ⁹ each represents a 1,4-phenylene group which may have an independent substituent. m and n each independently represent an integer of 1 to 3. ) In the powder X-ray diffraction spectrum by CuKα characteristic X-ray, the photosensitive layer has a crystal type oxytitanium phthalocyanine having a diffraction peak at a Bragg angle (2θ ± 0.2 °) of at least 24.1 ° and 27.2 °. The electrophotographic photosensitive member according to claim 1, which is contained. The charge transport material represented by the above formula (1) contained in the photosensitive layer is 20 to 50 parts by mass with respect to 100 parts by mass of the binder resin forming the photosensitive layer. The electrophotographic photosensitive member according to claim 1 or 2. The residual amount of the halogen-based solvent in the photosensitive layer is 1.0 mg / g or less, and the residual amount of the non-halogen-based solvent is 0.05 mg / g or more and 20.0 mg / g or less. ~
4. The electrophotographic photosensitive member according to any one of items 3. The electrophotographic photosensitive member according to any one of claims 1 to 4, a charging device for charging the electrophotographic photosensitive member, and exposure for forming an electrostatic latent image by exposing the charged electrophotographic photosensitive member. An electrophotographic photosensitive member cartridge comprising: an apparatus; and at least one selected from the group consisting of a developing device that develops an electrostatic latent image formed on the electrophotographic photosensitive member. The electrophotographic photosensitive member according to any one of claims 1 to 4, a charging device for charging the electrophotographic photosensitive member, and exposing the charged electrophotographic photosensitive member to form an electrostatic latent image. A full color tandem type image forming apparatus comprising an exposure device and a developing device for developing an electrostatic latent image formed on the electrophotographic photosensitive member.

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