JP2006184527A - Electrophotographic photoreceptor, image forming apparatus, and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor and an electrophotographic apparatus with high durability that can give favorable images without abnormal images such as black spots and fogging even in repeated use for a long period of time. <P>SOLUTION: A charge generating layer containing a phthalocyanine pigment having ≤0.3 μm average particle size and a benzoquinone derivative expressed by structural formula (I-I), a charge transporting layer formed of a charge transporting layer coating liquid containing a tetrahydrofuran solvent, and a surface protective layer are successively formed on a conductive support. In formula (I-I), each of R1 to R4 represents one of hydrogen, an alkyl group, an alkoxy group, an aryl group, an aralkyl group and a halogen group. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrophotographic photosensitive member for use in laser beam printers, facsimiles, digital copying, and the like, and an electrophotographic apparatus and a process cartridge using the same, and in particular, an electrophotographic photosensitive member having a charge generation layer containing a phthalocyanine pigment and a benzoquinone derivative. The present invention also relates to an image forming apparatus and a process cartridge having the photosensitive member.

  In recent years, there has been a remarkable development of information processing system machines using electrophotography. In particular, an optical printer that converts information into a digital signal and records information by light has a remarkable improvement in print quality and reliability. This digital recording technology is applied not only to printers but also to ordinary copying machines, and so-called digital copying machines have been developed.

  In addition, since a variety of information processing functions are added to a conventional copying machine equipped with this digital recording technology for analog copying, it is expected that its demand will increase further in the future. In addition, with the spread of personal computers and the improvement in performance, the progress of digital color printers for performing color output of images and documents is rapidly progressing.

  Electrophotographic photoreceptors (also referred to as photoreceptors) used in these electrophotographic image forming apparatuses are sensitive, thermal stability, and toxic to photoconductive materials such as Se, CdS, and ZnO that have been conventionally used. An electrophotographic photosensitive member using an organic photoconductive material having an advantage in the above has become mainstream.

  When forming a photosensitive layer of an electrophotographic photoreceptor using this organic photoconductive material, a function separation type in which a charge transport layer is laminated on a charge generation layer is generally used because of its excellent sensitivity and durability. . In addition to the above configuration, in order to increase the effect of concealing defects on the conductive support, and to increase the scattering effect on incident light such as coherent light (for example, laser light) to suppress the occurrence of interference fringes, It is well known to provide an intermediate layer in which an inorganic pigment such as titanium oxide is dispersed (see, for example, Patent Documents 1 and 2).

  Further, as a charge generation material contained in the charge generation layer, many charge generation materials such as various azo pigments, polycyclic quinone pigments, trigonal selenium, various phthalocyanine pigments have been developed. Among them, phthalocyanine pigments exhibit high sensitivity to light having a long wavelength of 600 to 800 nm, and thus are extremely important and useful as photoconductor materials for electrophotographic printers and digital copying machines whose light sources are LEDs and LDs. .

  On the other hand, the charge transport layer mainly comprises a charge transport material and a binder resin, and is generally formed by applying a coating solution in which these materials are dissolved or dispersed in a solvent. Halogen solvents such as dichloromethane and chloroform are mainly used because of their excellent solubility and coating properties.

  Furthermore, in order to increase the durability against mechanical wear, a method of providing a surface protective layer on the charge transport layer has been proposed, for example, a means of blending a high hardness filler has been proposed (see, for example, Patent Document 3). ). According to this means, mechanical durability and resistance to an electrical load can be imparted to the organic photoreceptor at a relatively low cost.

  However, there are cases where the photoreceptor to which this means is applied has an insufficient cleaning process in the electrophotographic apparatus. In addition, when adopting a configuration in which a large amount of high-hardness filler is blended, the sensitivity characteristic of the photoreceptor is deteriorated, which may limit the design flexibility of the electrophotographic process.

  Also proposed is a method for obtaining an electrophotographic photoreceptor having high mechanical strength and high wear resistance by providing a surface protective layer containing an organometallic polycondensation matrix component formed from an organometallic compound and a charge transport material. (For example, see Patent Document 4). However, since there are many cases where it is necessary to use a drum heater together for the purpose of suppressing image blurring, a disadvantage that is disadvantageous in reducing the power consumption of the electrophotographic apparatus is pointed out.

  In order to achieve the above-mentioned problems, not only the mechanical strength of the surface protective layer is increased, but also the surface smoothness of the photoreceptor is improved to improve the cleaning property, and the free energy of the photoreceptor surface is further reduced. It is necessary to make the image blur substance difficult to adhere in the present invention, but the applicant of the present invention is not limited to a crosslinkable charge transport material containing a reactive hydroxyl group, a thermosetting resin monomer, and a thermosetting surfactant. It has been found that the use of a surface protective layer formed by this crosslinking reaction makes it possible to extend the life of a photoreceptor for use in an electrophotographic apparatus for the first time.

  In recent years, awareness of environmental problems has increased, and development of a photoreceptor using a non-halogen solvent that has a low impact on the human body and the environment has been desired. Of these non-halogen solvents, tetrahydrofuran, in particular, has excellent characteristics as a solvent for a charge transport layer coating solution in terms of liquid properties such as solubility and boiling point and safety. However, when the charge transport layer is formed using the coating solution for the charge transport layer using the tetrahydrofuran solvent, there is no particular problem in the initial stage, but when mounted on an electrophotographic apparatus and used for a long time, There has been a problem that defects on the image such as black spots and fog are gradually becoming noticeable.

  As a cause of image defects that occur due to long-term use, since the electric field increase in the photosensitive layer caused by the abrasion of the photosensitive layer is not caused by the excellent mechanical strength of the surface protective layer, the conductive support. In order to solve such an abnormal image, the intermediate layer contains a metal oxide, which contributes to the increase in charge injection from the substrate or the decrease in chargeability due to the material of the charge generation material and the charge transport material. In addition, a method for preventing an increase in charge injection from the conductive support by having a specific surface roughness has been proposed (see, for example, Patent Document 5).

  However, even in this method, when an electrophotographic photosensitive member is produced using a coating solution for a charge transport layer using a tetrahydrofuran solvent, there is no particular problem in the initial stage. When it was used, there was a problem that defects on the image such as black spots and fog were gradually noticeable.

  Further, as another method for preventing such an increase in charge injection from the conductive support, an intermediate layer in which surface-treated titanium oxide is dispersed in a cross-linked product of a methoxymethylated polyamide resin and a melamine resin has been proposed. (For example, refer to Patent Document 6). However, when surface-treated titanium oxide is used, there is a problem that the residual potential tends to increase due to repeated use due to the effect of the surface treatment.

As a method for preventing defects on the image such as black spots and fogging caused by charge reduction due to repeated use, there has been proposed a method for preventing abnormal images by using a specific charge generation material and charge transport material ( For example, see Patent Documents 7 and 8). However, when a photoreceptor is prepared using a coating solution for a charge transport layer using a tetrahydrofuran solvent in this method, there is a problem that an abnormal image is generated due to repeated use.
JP-A-61-204642 Japanese Patent Laid-Open No. 62-280864 JP 2002-229227 A JP-A-9-222746 JP-A-11-202517 JP-A-9-269606 JP 2000-89493 A JP 2001-109178 A

  The present invention has been made in consideration of the above-described circumstances, and is a highly durable electrophotographic photosensitive member capable of obtaining a good image free of abnormal images such as black spots and fog even after repeated use over a long period of time. An object of the present invention is to provide an electrophotographic apparatus and a process cartridge including a photographic photosensitive member.

  In order to solve the above-mentioned problems, the invention described in claim 1 is a charge comprising a phthalocyanine pigment having an average particle size of 0.3 μm or less and a benzoquinone derivative represented by the following structural formula on a conductive support. An electrophotographic photoreceptor comprising a generation layer, a charge transport layer formed from a coating solution for a charge transport layer containing a tetrahydrofuran solvent, and a surface protective layer in this order.

（式（Ｉ-Ｉ）中、Ｒ１〜Ｒ４は、それぞれ独立して、水素原子、アルキル基、
アルコキシ基、アリール基、アラルキル基、ハロゲン基のうちのいずれか１つを表す）

(In the formula (II), R1 to R4 each independently represent a hydrogen atom, an alkyl group,
Represents any one of an alkoxy group, an aryl group, an aralkyl group, and a halogen group)

  In the invention according to claim 2, R1 to R4 of the benzoquinone derivative represented by the formula (II) contained in the charge generation layer containing the phthalocyanine pigment are each independently a hydrogen atom, Any one of an alkyl group, an alkoxy group, an aryl group, an aralkyl group, and a halogen group, and at least one group of R1 to R4 of the benzoquinone derivative represented by the formula (II). And a benzoquinone derivative (I-II) which is a halogen group.

The main feature of the invention according to claim 3 is that the content of the benzoquinone derivative is 1 to 30 wt% of the phthalocyanine pigment.
Further, in the invention according to claim 4, the surface protective layer is formed by a crosslinking reaction between a crosslinkable charge transport material containing at least a reactive hydroxyl group, a thermosetting resin monomer, and a thermosetting surfactant. The electrophotographic photoreceptor according to claim 1, wherein the content of the crosslinkable charge transport material is 7.5 wt% or more in the surface protective layer.

  The main feature of the invention according to claim 5 is the electrophotographic photosensitive member according to claim 4, wherein the thermosetting resin monomer is an amino resin or an amino resin mixture.

  The invention according to claim 6 is the reactivity in which the thermosetting surfactant is grafted with a copolymer of fluoroalkyl and acrylic acid, a copolymer of silicone and acrylic acid, or a silicone segment. 5. The electrophotographic photosensitive member according to claim 4, which is a hydroxyl group-containing fluororesin.

  In the invention according to claim 7, the phthalocyanine pigment contained in the charge generation layer has a maximum peak at 27.2 ± 0.2 ° with a Bragg angle 2θ with respect to the Cu—Kα ray (wavelength 1.542 mm). The electrophotographic photoreceptor according to any one of claims 1 to 3, which is a titanyl phthalocyanine pigment having a main feature.

  In the invention according to claim 8, the titanyl phthalocyanine has a maximum peak and a minimum angle of 7.3 ± 0.00 ° at a Bragg angle 2θ of 27.2 ± 0.2 ° with respect to the Cu—Kα ray (wavelength 1.542Å). The electrophotographic photosensitive member according to claim 7, which has a peak at 2 ° and does not have a peak in the range of 7.4 to 9.4 °.

  The invention according to claim 9 is mainly characterized in that the titanyl phthalocyanine further has no peak at 26.3 °.

  The invention according to claim 10 is an image forming apparatus on which an image forming element comprising at least a charging means, an image exposing means, a developing means, a transferring means, and an electrophotographic photosensitive member is mounted. An image forming apparatus, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of claims 1 to 9.

  The invention according to claim 11 is provided with at least an electrophotographic photosensitive member, and the electrophotographic photosensitive member is a photosensitive member according to any one of claims 1 to 9 (for example, an electrophotographic image forming apparatus). For most).

  According to the present invention, a charge generation layer containing a phthalocyanine pigment having an average particle size of 0.3 μm or less and a benzoquinone derivative represented by the previous structural formula (II) on a conductive support, and a tetrahydrofuran solvent The electrophotographic photosensitive member is provided with a charge transport layer formed from a coating solution for a charge transport layer and a surface protective layer in this order, so that black spots, fog, etc. are generated even in repeated use over a long period of time. Excellent electrophotographic photosensitive member, an electrophotographic apparatus using the electrophotographic photosensitive member, and a process cartridge for an electrophotographic apparatus can be provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Examples of the phthalocyanine pigment used in the present invention include metal-free phthalocyanine or metal phthalocyanine. Synthesis methods described in Moser and Thomas' “phthalocyanine compound” (Rheinhold, 1963), and other suitable methods Use the one obtained by

  Examples of metal phthalocyanines include those having a central metal such as copper, silver, beryllium, magnesium, calcium, zinc, indium, sodium, lithium, titanium, tin, lead, vanadium, chromium, manganese, iron, and cobalt. . Further, a metal halide having a valence of 3 or more may be present in the central nucleus of phthalocyanine instead of the metal atom. Various crystal forms of phthalocyanine are known, but known forms such as crystal forms such as α-type, β-type, Y-type, ε-type, τ-type, and X-type, and amorphous forms can be used.

  Furthermore, according to the present invention, as shown below, titanyl phthalocyanine (hereinafter referred to as TiOPc) having titanium as a central metal is particularly desirable because of its particularly high sensitivity and excellent characteristics.

（式中、Ｘ₁、Ｘ₂、Ｘ₃、Ｘ₄は各々独立に各種ハロゲン原子を表わし、ｎ、ｍ、ｌ、ｋは各々独立的に０〜４の数字を表わす）

(In the formula, X ₁ , X ₂ , X ₃ and X ₄ each independently represent various halogen atoms, and n, m, l and k each independently represent a number of 0 to 4)

  References relating to the synthesis method and electrophotographic characteristics of TiOPc include, for example, JP-A-57-148745, JP-A-59-36254, JP-A-59-44054, JP-A-59-31965, JP-A 61-239248, JP-A 62-67094 and the like can be mentioned. Various crystal systems are known for TiOPc. JP 59-49544 A, JP 59-41616959 A, JP 61-239248 A, and JP 62-67094 A. JP-A-63-366, JP-A-63-116158, JP-A-63-196067, JP-A-64-17066, JP-A-2001-19871, etc. Different TiOPc are described.

  Of these crystal forms, TiOPc having a maximum diffraction peak at a Bragg angle 2θ of 27.2 ° exhibits particularly excellent sensitivity characteristics and is used favorably. In particular, it has a maximum diffraction peak at 27.2 ° described in JP-A-2001-19871, and has a peak at 7.3 ° as the lowest diffraction peak, and 7.4. By using TiOPc having no peak in the range of ˜9.4 °, it is possible to obtain a stable electrophotographic photosensitive member that does not lose chargeability even if it is repeatedly used without losing high sensitivity. Furthermore, the use of a crystal type that does not have a peak at 26.3 ° among the above crystal types can make the effects of the present invention more remarkable.

  Further, in the present invention, by using the above-mentioned titanyl phthalocyanine pigment having an average particle diameter of 0.3 μm or less, the moving distance to the particle surface of the photocarrier generated inside the charge generation material particles is shortened, Because it shows a particularly excellent sensitivity characteristic due to an increase in photocarrier injection efficiency based on a decrease in the probability of deactivation and an increase in the amount of contact with the charge transport material surrounding the pigment particle surface as the surface area increases. desirable.

  As a method for obtaining the average particle diameter of the charge generating material, it can be obtained by observing with an electron microscope a coating film formed by applying a dispersion. The particle shape of the charge generation material has various forms such as a rice grain shape and a needle shape, and can take any form. Therefore, in the case of direct observation, the average particle diameter can be obtained by measuring the length in the major axis direction of a plurality of particles (at least 10 particles) and calculating the arithmetic average.

  Further, in the present invention, the applicant of the present invention is formed from a coating solution for a charge transport layer containing a tetrahydrofuran solvent by containing the benzoquinone derivative represented by the structural formula (II) in the charge generation layer. In the electrophotographic photosensitive member provided with the charge transport layer and the surface protective layer, it has been found that abnormal images such as black spots and fogging can be suppressed when used repeatedly over a long period of time.

  Although it is not clear about the factors showing the above excellent characteristics, as a result of the study, particularly when forming the surface protective layer on the charge transport layer formed from the coating liquid for the charge transport layer containing the tetrahydrofuran solvent, Due to the drying process after coating the surface protective layer, abnormal images such as black spots and fog are likely to occur in repeated use over a long period of time, and as a surface protective layer provided on the charge transport layer, crosslinkability containing a reactive hydroxyl group When a surface protective layer formed by a crosslinking reaction of a charge transport material, a thermosetting resin monomer, and a thermosetting surfactant is provided, it is necessary to supply a large amount of heat especially during thermosetting. From a photoreceptor including a charge transport layer formed from a coating solution for a charge transport layer containing a tetrahydrofuran solvent, such as black spots and fog in repeated use over a long period of time. Normal image tends occur particularly, by containing a benzoquinone derivative of the formula in the charge generating layer containing a titanyl phthalocyanine (I-I), was found to be able to suppress the abnormal image. Furthermore, it has been found that the inclusion of the benzoquinone derivative of the formula (I-II) has a particularly excellent abnormal image suppressing effect.

  Examples of the benzoquinone derivatives include 2-bromo-5-methyl-1,4-benzoquinone, 2-bromo-1,4-benzoquinone, 2-tertiarybutyl-1,4-benzoquinone, 2-chloro-5-methyl- 1,4-benzoquinone, 2,5-di-tertiarybutyl-1,4-benzoquinone, 2,5-dichloro-1,4-benzoquinone, 2,6-dichloro-1,4-benzoquinone, 2,5- Dimethyl-1,4-benzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,5-di-tertiary-amylbenzoquinone, 2,6-dimethyl-1,4-benzoquinone, 2, 5-dibromo-1,4-benzoquinone, 2,5-dimethoxy-1,4-benzoquinone, 2,6-di-tert-butyl-1,4-benzoquinone, 2,6-dimethyl Xy-1,4-benzoquinone, methyl-p-benzoquinone, methoxybenzoquinone, tetrachloro-p-benzoquinone, tetrabromo-p-benzoquinone, tetramethyl-1,4-benzoquinone, tetrafluoro-1,4-benzoquinone, 5- Examples include isopropyl-2-methyl-1,4-benzoquinone, tetrahydroxy-1,4-benzoquinone, and methyl-p-benzoquinone.

  In the present invention, the crosslinkable charge transport material containing a reactive hydroxyl group, a thermosetting resin monomer, and a thermosetting surfactant are formed by a cross-linking reaction, and the content of the crosslinkable charge transport material is By providing a surface protective layer of 7.5 wt% or more in the surface protective layer, it is possible to achieve particularly high mechanical strength, low surface energy, and excellent electrical characteristics.

  Examples of the crosslinkable charge transport material containing a reactive hydroxyl group include those represented by the following structural formula.

  The thermosetting resin monomer used in the surface protective layer in the present invention is preferably an amino resin or an amino resin mixture. As the surfactant, a known material can be used. For example, as a copolymer containing (1) (meth) acrylate having a fluoroalkyl group described in JP-A-07-068398, label number [0017], for example, JP-A-60-212410 and JP-A-0 A block copolymer comprising a fluorine-free vinyl monomer and a fluorine-containing vinyl monomer described in JP-A-60-228588, and (2) a fluorine-based graft polymer, for example, described in JP-A-60-187721 Examples thereof include a comb-type graft polymer obtained by copolymerizing a methacrylate macromonomer having polymethyl methacrylate in the side chain and a (meth) acrylate having a fluoroalkyl group. These fluororesins are commercially available as paint additives. For example, fluorine-containing random copolymers are commercially available from Asahi Glass Co., Ltd. as resin surface modifiers SC-101 and SC-105. As a fluorine-containing block copolymer, a product name Modiper F series (for example, F100, F110, and the like) commercially available from Nippon Oil & Fats Co., Ltd. as a block copolymer comprising a fluorinated alkyl group-containing polymer segment and an acrylic polymer segment. F200, F210, F2020). Fluorine-based graft polymers are commercially available from Toa Gosei Co., Ltd. under the names Aron GF-150, GF-300, and RESEDA GF-2000. These surfactants may be used alone or as a crosslinked resin component. In particular, in the present invention, a copolymer of a methacrylic acid ester and a fluoroalkyl acrylate is effective.

Next, the electrophotographic photosensitive member used in the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing a configuration example of an electrophotographic photosensitive member used in the present invention. On a conductive support 31, an intermediate layer 33, a charge generation layer 35 mainly composed of a charge generation material, and a charge A charge transport layer 37 mainly composed of a transport material is provided, and a protective layer 39 is laminated thereon.

Examples of the conductive support 31 include those having a volume resistance of 10 ¹⁰ Ω · cm or less, for example, metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, indium oxide, etc. The metal oxide of the above is coated with film or cylindrical plastic or paper by vapor deposition or sputtering, or a plate made of aluminum, aluminum alloy, nickel, stainless steel or the like and extruded by drawing or drawing. Examples thereof include endless nickel belts and endless stainless steel belts described in JP-A-52-36016, a method of forming a continuous roughness with a cutting tool on the surface of these, and liquid honing. By superfinishing, wet or dry blasting, or forming an anodized film Those surface roughening treatment is also preferably used.

  In the present invention, an intermediate layer may be provided for the purpose of improving adhesiveness, preventing moire, improving coatability of the upper layer, reducing residual potential, and preventing charge injection from the conductive support. .

  In general, the intermediate layer is mainly composed of a resin. However, considering that the photosensitive layer is applied on the resin using a solvent, the intermediate layer may be a resin having a high resistance to a general organic solvent. Desirably, such resins include water-soluble resins such as polyvinyl alcohol, casein and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resins, alkyd-melamine resins, and epoxy resins. And a curable resin that forms a three-dimensional network structure.

  Further, fine powders such as metal oxides such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, and indium oxide, or metal sulfides and metal nitrides may be added to the intermediate layer. These intermediate layers can also be added with additives.

  In addition, as a dispersion method of the intermediate layer coating liquid, the above-mentioned pigment coarse powder is ball mill, vibration mill, disk vibration mill, attritor, sand mill, bead mill, paint shaker, jet mill, ultrasonic dispersion method, etc. in the presence of a dispersion solvent. And a method of performing atomization treatment by a pulverizing means that gives mechanical energy such as compression, shearing, grinding, friction, stretching, impact, vibration to the pigment.

  As a coating method of the coating solution, methods such as dip coating, spray coating, beat coating, nozzle coating, spinner coating, ring coating and the like can be used, and it is preferable to form the coating liquid in a thickness of 0.1 to 5 μm.

Next, the photosensitive layer will be described.
As described above, the laminated type composed of the charge generation layer 35 and the charge transport layer 37 exhibits excellent characteristics in sensitivity and durability, and is used favorably. The charge generation layer 35 is formed by dispersing the above-described organic pigment as a charge generation material in a solvent together with an appropriate resin, coating the conductive pigment on a conductive support, and drying. And as a coating method, it is possible to use the above-mentioned method.

  Suitable resins include polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, polyacrylamide and the like. These binder resins can be used alone or as a mixture of two or more.

  The solvent is preferably a non-halogen solvent such as methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, cyclohexane, toluene, xylene, ligroin and the like. These charge generation layers can be added with additives and the like, and the film thickness is suitably about 0.01 to 5 μm, preferably 0.1 to 2 μm.

  As described above, the charge transport layer 37 can be formed by dissolving or dispersing a charge transport material and a binder resin in a tetrahydrofuran solvent, and applying and drying the solution on the charge generation layer. In addition to tetrahydrofuran alone, the solvent is useful as a mixed solvent with cyclic ethers such as dioxolane and dioxane, aromatic hydrocarbons such as toluene and xylene, and derivatives thereof.

  Charge transport materials include hole transport materials and electron transport materials. Examples of the electron transporting material include chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and benzoquinone derivatives.

  Examples of hole transport materials include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazolines Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc., bisstilbene derivatives, enamine derivatives, etc. Other known materials may be mentioned. These charge transport materials may be used alone or in combination of two or more.

  Binder resins include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, poly Vinylidene chloride, polyarate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin And thermoplastic or thermosetting resins such as alkyd resins, and polycarbonate in particular exhibits excellent electrical characteristics and wear resistance.

  The amount of the charge transport material is appropriately 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. The thickness of the charge transport layer is preferably about 5 to 100 μm.

  In the present invention, a plasticizer or a leveling agent may be added to the charge transport layer 37. As the plasticizer, those used as general plasticizers such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is suitably about 0 to 30% by weight based on the binder resin. As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain are used, and the amount used is 0 to 0 with respect to the binder resin. 1% by weight is suitable.

  In the present invention, the surface protective layer 39 is provided in order to prevent an electric field increase in the photosensitive layer caused by wear of the charge transport layer and to achieve a long life of the photosensitive member in use in the electrophotographic apparatus. is there. In the surface protective layer, a surface protective layer formed by a cross-linking reaction between the above-described crosslinkable charge transporting material containing a reactive hydroxyl group, a thermosetting resin monomer, and a thermosetting surfactant is particularly preferable. In addition, any of a resin film, an organic filler-containing resin film, an inorganic filler-containing resin film, and those obtained by adding a charge transport material to these resin films can be used.

  Materials used for the protective layer 39) include ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyacrylate. Allylsulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyarylate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer Resin such as polyurethane, polyvinyl chloride, polyvinylidene chloride, epoxy resin, fluorine resin such as polytetrafluoroethylene, silicone resin, etc. It is below. Also, those obtained by dispersing inorganic materials such as titanium oxide, aluminum oxide, tin oxide, zinc oxide, zirconium oxide, magnesium oxide, potassium titanate, silica, and surface-treated products thereof in these resins can be used.

  Among the filler materials used for the protective layer of the photoreceptor, examples of the organic filler material include fluororesin powder such as polytetrafluoroethylene, silicone resin powder, a-carbon powder, and the like. Metals such as copper, tin, aluminum, indium, etc., metals such as silica, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, antimony-doped tin oxide, tin-doped indium oxide Inorganic materials such as oxide and potassium titanate can be mentioned.

In particular, from the viewpoint of the hardness of the filler, it is advantageous to use an inorganic material. Among them, silica, titanium oxide, and alumina can be used particularly effectively, and electrical insulation is high (specific resistance is 10 ¹⁰ Ω). (Cm or more) It can be effectively used as a filler that hardly causes image blur. Furthermore, among these, α-alumina having a hexagonal close-packed structure can be most effectively used from the viewpoint of suppressing image blur and improving wear resistance.

  The filler concentration in the protective layer varies depending on the type of filler used and also on the electrophotographic process conditions using the photoreceptor, but the ratio of the filler to the total solid content on the outermost layer side of the protective layer is preferably 5% by weight or more, 10 wt% or more and 50 wt% or less, preferably 30 wt% or less (in the range of 5 wt% or more and 50 wt% or less, preferably in the range of 10 wt% or more and 50 wt% or less, or preferably 5 wt% In the range of 30% by weight or less, more preferably in the range of 10% by weight or more and 30% by weight or less.

  Moreover, the volume average particle diameter of the filler to be used is preferably in the range of 0.1 μm to 2 μm, and preferably in the range of 0.3 μm to 1 μm. In this case, if the average particle size is too small, the wear resistance is not sufficiently exhibited, and if it is too large, the surface property of the coating film is deteriorated or the coating film itself cannot be formed.

  The specific resistance of the filler used in the present invention is defined as follows. Since the specific resistance value of a powder such as a filler varies depending on the filling rate, it is necessary to measure under certain conditions.

In the present invention, the specific resistance value of the filler using the apparatus shown in FIG. 1 of JP-A-5-94049 and the apparatus having the same configuration as the measuring apparatus shown in FIG. 1 of JP-A-5-113688. Was measured and this value was used. In the measuring apparatus, the electrode area is 4.0 cm ² . Prior to measurement, a load of 4 kg is applied to one electrode for 1 minute, and the sample amount is adjusted so that the distance between the electrodes is 4 mm.

  At the time of measurement, the measurement is performed with the upper electrode weight (1 kg) loaded, and the applied voltage is measured at 100V. The area of 106 Ω · cm or higher was measured with a HIGH RESISTANCE METER (manufactured by Yokogawa Hewlett-Packard), and the area below it was measured with a digital multimeter (manufactured by Fluke). The specific resistance value thus obtained is defined as the specific resistance value of the present invention.

  Further, these fillers can be surface-treated with at least one kind of surface treatment agent, and it is preferable from the viewpoint of dispersibility of the fillers. Decreasing the dispersibility of the filler not only increases the residual potential, but also decreases the transparency of the coating, causes defects in the coating, and decreases the wear resistance. It can develop into a big problem. As the surface treatment agent, a conventionally used surface treatment agent can be used, but a surface treatment agent capable of maintaining the insulating properties of the filler is preferable.

For example, a titanate coupling agent, an aluminum coupling agent, a zircoaluminate coupling agent, a higher fatty acid, etc., or a mixed treatment of these with a silane coupling agent, Al ₂ O ₃ , TiO ₂ , ZrO ₂ , Silicone, aluminum stearate, or the like, or a mixture thereof is more preferable from the viewpoint of filler dispersibility and image blur.

  The treatment with the silane coupling agent is strongly influenced by image blur, but the influence may be suppressed by performing a mixing treatment of the surface treatment agent and the silane coupling agent. The surface treatment amount varies depending on the average primary particle size of the filler used, but is preferably 3 to 30 wt%, more preferably 5 to 20 wt%.

  If the surface treatment amount is less than this, the filler dispersion effect cannot be obtained, and if it is too much, the residual potential is significantly increased. These filler materials may be used alone or in combination of two or more. The surface treatment amount of the filler is defined by the weight ratio of the surface treatment agent to be used with respect to the filler amount as described above.

  These filler materials can be dispersed by using an appropriate disperser. Further, from the viewpoint of the transmittance of the protective layer, it is preferable that the filler used is dispersed to the primary particle level and has less aggregates.

  In addition, a charge transport material can be added to the protective layer to improve high-speed response and reduce residual potential. As the charge transport material that can be used for the protective layer, the charge transport materials described in the description of the charge transport layer are used.

  The use of a polymer charge transport material is very effective in increasing the durability of the photoreceptor. By constituting the components other than the filler of the protective layer only with the polymer, not only the mechanical wear resistance can be improved, but also the chemical stability can be enhanced.

  A polymer is poor in chemical reactivity compared to a low molecule, and has a high resistance to an oxidizing gas generated from a charging member or a resistance to a sputtering effect caused by a discharge. When a film having high abrasion resistance such as a protective layer is provided on the surface, the problem of image blur due to repeated use becomes very significant. This is thought to be due to adsorption of oxidizing gas and adhesion (adsorption) of low-resistance substances on the surface of the photoconductor. However, as described above, a protective layer consisting only of filler and polymer components is used. In this case, the number of adsorption sites is reduced, which shows a high effect on image blur. As a method for forming the protective layer, a normal coating method is employed. In addition, about 0.1-10 micrometers is suitable for the thickness of a protective layer.

  Next, an electrophotographic image forming apparatus equipped with the novel electrophotographic photosensitive member of the present invention will be described in detail. FIG. 2 is a schematic view for explaining the electrophotographic process and the electrophotographic image forming apparatus of the present invention.

  In FIG. 2, the photoreceptor 41 is formed by providing a photosensitive layer including at least a charge generation layer and a charge transport layer on a conductive support. The photoconductor 41 has a drum shape, but may have a sheet shape or an endless belt shape. For the charging roller 43, the pre-transfer charger 47, the transfer charger 50, the separation charger 51, and the pre-cleaning charger 53, a known corotron, a scorotron, a solid state charger, a charging roller, and a transfer roller are known. Means are used.

  Among these charging methods, the contact charging method or the non-contact proximity arrangement method is more desirable, and has advantages such as high charging efficiency, a small amount of ozone generation, and miniaturization of the apparatus. The light source such as the image exposure unit 45 and the static elimination lamp 42 emits light such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL). All things can be used.

  In addition, various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.

  Among these light sources, light emitting diodes and semiconductor lasers have high irradiation energy and long wavelength light of 600 to 800 nm, so that the above-mentioned phthalocyanine pigment, which is a charge generation material, exhibits high sensitivity and is used well. The

  Such a light source or the like irradiates the photosensitive member with light by providing a transfer process, a static elimination process, a cleaning process, or a pre-exposure process using light irradiation in addition to the process shown in FIG.

  The toner developed on the photoconductor 41 by the developing unit 46 is transferred to the transfer paper 49, but not all is transferred, and toner remaining on the photoconductor 41 is also generated. Such toner is removed from the photoreceptor by the fur brush 54 and the blade 55. Cleaning may be performed only with a cleaning brush, and a known brush such as a fur brush or a mag fur brush is used as the cleaning brush.

  When the electrophotographic photosensitive member is positively (negatively) charged and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. If this is developed with toner of negative (positive) polarity (electrodetection fine particles), a positive image can be obtained, and if developed with toner of positive (negative) polarity, a negative image can be obtained. A known method is applied to the developing unit, and a known method is also used for the charge eliminating unit.

Next, an image forming element on which the novel electrophotographic photosensitive member of the present invention is mounted will be described.
In the case of a color electrophotographic image forming apparatus in which an image forming element is configured as a unit in which an electrophotographic photosensitive member and at least a charging member, a developing member, and a cleaning member are disposed around the electrophotographic photosensitive member, The number of image forming elements corresponding to the number of colors is mounted, and each image forming element can be fixed to the image forming apparatus or can be individually replaced.

  FIG. 3 is a schematic diagram for explaining an electrophotographic image forming apparatus (generally called a tandem full-color electrophotographic image forming apparatus) having a plurality of image forming elements. Modifications also belong to the category of the present invention.

  In FIG. 3, reference numerals 1C, 1M, 1Y, and 1K denote drum-shaped photoconductors. The photoconductors 1C, 1M, 1Y, and 1K rotate in the direction of the arrow in the drawing, and at least in the order of rotation around the charging member 2C. , 2M, 2Y, 2K, developing members 4C, 4M, 4Y, 4K, and cleaning members 5C, 5M, 5Y, 5K are arranged. The charging members 2C, 2M, 2Y, and 2K are charging members that constitute a charging device for uniformly charging the surface of the photoreceptor.

  Laser light 3C, 3M, 3Y, 3K from an exposure member (not shown) is irradiated from the back side of the photosensitive member between the charging members 2C, 2M, 2Y, 2K and the developing members 4C, 4M, 4Y, 4K, and the photosensitive member. Electrostatic latent images are formed on 1C, 1M, 1Y, and 1K. Then, four image forming elements 6C, 6M, 6Y, and 6K centering on such photoreceptors 1C, 1M, 1Y, and 1K are juxtaposed along a transfer conveyance belt 10 that is a transfer material conveyance unit. The transfer conveyance belt 10 contacts the photoreceptors 1C, 1M, 1Y, and 1K between the developing members 4C, 4M, 4Y, and 4K of the image forming units 6C, 6M, 6Y, and 6K and the cleaning members 5C, 5M, 5Y, and 5K. Transfer brushes 11C, 11M, 11Y, and 11K for applying a transfer bias are disposed on a surface (back surface) that is in contact with the back side of the transfer conveyance belt 10 on the photoconductor side. Each of the image forming elements 6C, 6M, 6Y, and 6K is different in the color of the toner inside the developing device, and the others are the same in configuration.

  In the color electrophotographic image forming apparatus having the configuration shown in FIG. 3, the image forming operation is performed as follows. First, in each of the image forming elements 6C, 6M, 6Y, and 6K, the photoreceptors 1C, 1M, 1Y, and 1K are charged by the charging members 2C, 2M, 2Y, and 2K that rotate in the direction of the arrow (the direction along with the photoreceptor). Next, an electrostatic latent image corresponding to each color image to be created is formed by laser beams 3C, 3M, 3Y, and 3K at an exposure unit (not shown) disposed inside the photoconductor.

  Next, the latent image is developed by developing members 4C, 4M, 4Y, and 4K to form a toner image. Development members 4C, 4M, 4Y, and 4K are development members that perform development with toners of C cyan, M magenta, Y yellow, and K black, respectively, and the colors formed on the four photoreceptors 1C, 1M, 1Y, and 1K. The toner images are superimposed on the transfer paper.

  The transfer paper 7 is sent out from the tray by a paper feed roller 8, temporarily stopped by a pair of registration rollers 9, and sent to the transfer conveyance belt 10 in synchronism with the image formation on the photosensitive member. The transfer paper 7 held on the transfer conveyance belt 10 is conveyed, and the toner images of the respective colors are transferred at the contact positions (transfer portions) with the photoconductors 1C, 1M, 1Y, 1K.

  The toner image on the photoconductor is transferred onto the transfer paper 7 by an electric field formed from a potential difference between the transfer bias applied to the transfer brushes 11C, 11M, 11Y, and 11K and the photoconductors 1C, 1M, 1Y, and 1K. The Then, the recording paper 7 on which the four color toner images are passed through the four transfer portions is conveyed to the fixing device 12, where the toner is fixed, and is discharged to a paper discharge portion (not shown). Further, the residual toner remaining on the photoreceptors 1C, 1M, 1Y, and 1K without being transferred by the transfer unit is collected by the cleaning devices 5C, 5M, 5Y, and 5K.

  In the example of FIG. 3, the image forming elements are arranged in the order of C (cyan), M (magenta), Y (yellow), and K (black) from the upstream side to the downstream side in the transfer sheet conveyance direction. However, it is not limited to this order, and the color order is arbitrarily set. Further, when a black-only document is created, it is particularly effective to use the present invention to provide a mechanism for stopping the image forming elements (6C, 6M, 6Y) other than black.

  Further, in the example of FIG. 4, the charging member 17 is in contact with the photoreceptor 1, but by providing an appropriate gap (about 10 to 200 μm) between them, the wear amount of both can be reduced and the charging member Therefore, it can be used satisfactorily.

  The image forming element described above may be fixedly incorporated in an electrophotographic image forming apparatus such as a copying machine, a facsimile machine, or a printer. However, the image forming element is incorporated into the apparatus in the form of a process cartridge. May be.

  In addition, the process cartridge does not mean the image forming element used in a full-color electrophotographic image forming apparatus, but is configured to be detachable from a monocolor image forming apparatus for image formation of only one color, A device incorporating the electrophotographic photosensitive member of the present invention and further including at least one of a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a neutralizing unit and the like is also included in the present invention. Of the image forming units, those not provided in the process cartridge are provided on the image forming apparatus side.

  Although there are many shapes and the like of the process cartridge, a general example is shown in FIG. 4. However, since this configuration is well-known, it is shown only and its detailed description is omitted.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not restrict | limited by an Example. All parts are parts by weight.

First, the following intermediate layer coating solution prepared by ball mill dispersion for 72 hours was applied to an aluminum drum having a diameter of 30 mm and a length of 340 mm, and dried at 125 ° C. for 20 minutes to form an intermediate layer having a thickness of 3 μm.
[Coating liquid for intermediate layer]
Titanium oxide (CR-EL: manufactured by Ishihara Sangyo Co., Ltd.) 70 parts Alkyd resin 15 parts {Beckolite M6401-50-S (solid content 50%): manufactured by Dainippon Ink and Chemicals, Inc.}
Melamine resin 10 parts {Super Becamine L-121-60 (solid content 60%): manufactured by Dainippon Ink and Chemicals, Inc.}
100 parts of methyl ethyl ketone Next, the synthesis of titanyl phthalocyanine was carried out by the following procedure.

<Synthesis example>
29.2 g of 1,3-diiminoisoindoline and 200 ml of sulfolane are mixed, and 20.4 g of titanium tetrabutoxide is added dropwise under a nitrogen stream. After completion of the dropwise addition, the temperature was gradually raised to 180 ° C., and the reaction was carried out by stirring for 5 hours while maintaining the reaction temperature between 170 ° C. and 180 ° C. After completion of the reaction, the mixture was allowed to cool, and then the precipitate was filtered, washed with chloroform until the powder turned blue, then washed several times with methanol, further washed several times with hot water at 80 ° C., and dried. Crude titanyl phthalocyanine was obtained.

  Dissolve the crude titanyl phthalocyanine in 20 times the amount of concentrated sulfuric acid, add dropwise to 100 times the amount of ice water with stirring, filter the precipitated crystals, and then repeat washing with water until the washing solution becomes neutral. Got. 2 g of the obtained wet cake was put into 20 g of tetrahydrofuran and stirred for 4 hours.

  100 g of methanol was added to this and stirred for 1 hour, followed by filtration and drying to obtain a titanyl phthalocyanine powder of the present invention. The obtained titanyl phthalocyanine powder was subjected to X-ray diffraction spectrum measurement under the following conditions. As a result, the Bragg angle 2θ with respect to Cu-Kα ray (wavelength 1.542Å) was 27.2 ± 0.2 °, and the maximum peak and minimum angle 7 A titanyl phthalocyanine powder having a peak at .3 ± 0.2 °, no peak in the range of 7.4 to 9.4 °, and no peak at 26.3 ° was obtained. The result is shown in FIG.

(X-ray diffraction spectrum measurement conditions)
X-ray tube: Cu
Voltage: 50kV
Current: 30mA
Scanning speed: 2 ° / min Scanning range: 3 ° -40 °
Time constant: 2 seconds

  Next, the resulting titanyl phthalocyanine powder was dip coated with a coating solution for a charge generation layer having the following composition prepared by bead milling dispersion so that the average particle size of the pigment was 0.2 μm. Then, it dried at 80 degreeC for 20 minute (s), and formed the charge generation layer with a film thickness of 0.2 micrometer.

[Coating liquid for charge generation layer]
Titanyl phthalocyanine pigment of Synthesis Example 1 15 parts 2,5-dichloro-1,4-benzoquinone 1.5 parts Polyvinyl butyral (ESREC BX-1: manufactured by Sekisui Chemical Co., Ltd.) 10 parts Methyl ethyl ketone 600 parts

  Subsequently, a charge transport layer coating solution having the following composition was applied onto the charge generation layer and dried at 135 ° C. for 20 minutes to form a charge transport layer having a thickness of 22 μm.

[Coating fluid for charge transport layer]
Polycarbonate (Iupilon Z200: Mitsubishi Gas Chemical Co., Ltd. 10 parts Charge transport material of the following structural formula (A) 8 parts Tetrahydrofuran 80 parts

  Next, a surface protective layer coating solution having the following composition was applied onto the charge transport layer and dried at 170 ° C. for 30 minutes to form a charge transport layer having a thickness of 5 μm.

[Coating liquid for surface protective layer]
3 parts by weight of a low molecular charge transport material of the following structural formula (B)

（Ｂ）

(B)

Fluorosurfactant (Modiper F200, manufactured by NOF Corporation)
2.3 parts by weight (solid content: 0.7 parts by weight)
Melamine resin (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals) 10.5 parts by weight Tetrahydrofuran 180 parts by weight Cyclohexanone 50 parts by weight

  In place of 2,5-dichloro-1,4-benzoquinone used in the charge generation layer coating solution, except that 2-chloro-5-methyl-1,4-benzoquinone was used, the same as in Example 1, An electrophotographic photosensitive member was produced.

  An electrophotographic photoreceptor in the same manner as in Example 1 except that 2-bromo-1,4-benzoquinone was used instead of 2,5-dichloro-1,4-benzoquinone used in the charge generation layer coating solution. Was made.

  In the same manner as in Example 1, except that 2,5-dimethoxy-1,4-benzoquinone was used instead of 2,5-dichloro-1,4-benzoquinone used in the coating solution for the charge generation layer, an electrophotography was used. A photoconductor was prepared.

  In the same manner as in Example 1, except that 2,6-dimethyl-1,4-benzoquinone was used in place of 2,5-dichloro-1,4-benzoquinone used in the coating solution for the charge generation layer, electrophotography was performed. A photoconductor was prepared.

(Comparative Example 1)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that 2,5-dichloro-1,4-benzoquinone used in the charge generation layer coating solution was not contained.

(Comparative Example 2)
The same procedure as in Example 1 was conducted except that 3,5-di-tert-butyl-1,2-benzoquinone was used instead of 2,5-dichloro-1,4-benzoquinone used in the charge generation layer coating solution. Thus, an electrophotographic photosensitive member was produced.

(Comparative Example 3)
Example 1 was used except that 2,5-dihydroxy-3,6-dinitro-1,4-benzoquinone was used instead of 2,5-dichloro-1,4-benzoquinone used in the charge generation layer coating solution. Similarly, an electrophotographic photosensitive member was produced.

  An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the content of 2,5-dichloro-1,4-benzoquinone used in the charge generation layer coating solution was changed to 0.5 part.

  An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the content of 2,5-dichloro-1,4-benzoquinone used in the charge generation layer coating solution was changed to 0.1 part.

  An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that the content of 2,5-dichloro-1,4-benzoquinone used in the charge generation layer coating solution was changed to 3 parts.

An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the content of 2,5-dichloro-1,4-benzoquinone used in the charge generation layer coating solution was changed to 5 parts.
The obtained electrophotographic photosensitive member was mounted on a process cartridge for an electrophotographic apparatus as shown in FIG.

  It is mounted on an electrophotographic image forming apparatus (image MF-2200 manufactured by Ricoh Co., Ltd.) that uses a semiconductor laser of 780 nm as the image exposure means and a contact roller charger as the charging means, and A4 size PPC paper is fed in the vertical direction. The dark portion potential Vd and the light portion potential Vl were measured before and after 100,000 sheets were passed, and image evaluation was performed. The image evaluation was performed by visually measuring the number of black spots when a white solid image was output. The results are shown in Table 1.

  An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that the charge transport layer coating solution shown below was used.

[Coating fluid for charge transport layer]
Polycarbonate (Iupilon Z200: Mitsubishi Gas Chemical Co., Ltd. 10 parts Charge transport material of the structural formula (A) 8 parts Tetrahydrofuran 60 parts Methoxybenzene 20 parts

  An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that the charge transport layer coating solution shown below was used.

[Coating fluid for charge transport layer]
Polycarbonate (Iupilon Z200: Mitsubishi Gas Chemical Co., Ltd. 10 parts Charge transport material of the structural formula (A) 8 parts Tetrahydrofuran 60 parts Toluene 20 parts

(Comparative Example 4)
An electrophotographic photosensitive member was produced in the same manner as in Example 10 except that 2,5-dichloro-1,4-benzoquinone used in the charge generation layer coating solution was not contained.

(Comparative Example 5)
An electrophotographic photosensitive member was produced in the same manner as in Example 11 except that it did not contain 2,5-dichloro-1,4-benzoquinone used in the charge generation layer coating solution.

  An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that titanyl phthalocyanine powder was prepared by bead milling dispersion so that the average particle size of the pigment became 0.3 μm.

(Comparative Example 6)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that titanyl phthalocyanine powder was prepared by bead milling dispersion so that the average particle size of the pigment was 0.5 μm.
The obtained electrophotographic photosensitive member was mounted on a process cartridge for an electrophotographic apparatus as shown in FIG.

It is mounted on an electrophotographic image forming apparatus (image MF-2200 manufactured by Ricoh Co., Ltd.) that uses a semiconductor laser of 780 nm as the image exposure means and a contact roller charger as the charging means, and A4 size PPC paper is fed in the vertical direction. The dark portion potential Vd and the light portion potential Vl were measured before and after 100,000 sheets were passed, and image evaluation was performed. The image evaluation was performed by visually measuring the number of black spots when a white solid image was output. The results are shown in Table 2.

A photoconductor was prepared in the same manner as in Example 1 except that the surface protective layer coating solution used in Example 1 was changed to the following.

[Coating liquid for surface protective layer]
Low molecular charge transport material of structural formula (B) 3 parts by weight fluorinated surfactant (Modiper F200, manufactured by NOF Corporation)
2.3 parts by weight (solid content: 0.7 parts by weight)
Melamine resin (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals)
10.5 parts by weight (solid content: 6.3 parts by weight)
Leveling agent (BYK-Silclean 3700, manufactured by Big Chemie)
1 part by weight tetrahydrofuran 150 parts by weight cyclohexanone 50 parts by weight

A photoconductor was prepared in the same manner as in Example 1 except that the surface protective layer coating solution used in Example 1 was changed to the following.

[Coating liquid for surface protective layer]
Low molecular charge transport material of structural formula (B) 1 part by weight fluorosurfactant (Modiper F200, manufactured by NOF Corporation)
7 parts by weight (solid content: 2.1 parts by weight)
Melamine resin (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals)
10.5 parts by weight tetrahydrofuran 180 parts by weight cyclohexanone 50 parts by weight

A photoconductor was prepared in the same manner as in Example 1 except that the surface protective layer coating solution used in Example 1 was changed to the following.

[Coating liquid for surface protective layer]
3 parts by weight of low molecular charge transport material of the structural formula (B) 0.5 parts by weight of polymer charge transport material having the following structure

（Ｃ）

(C)

Silicone modified fluororesin (ZX-007C, manufactured by Fuji Kasei Kogyo Co., Ltd.)
2.0 parts by weight (solid content: 0.7 parts by weight)
Melamine resin (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals)
10.5 parts by weight (solid content: 6.3 parts by weight)
Tetrahydrofuran 150 parts by weight Cyclohexanone 50 parts by weight

A photoconductor was prepared in the same manner as in Example 1 except that the surface protective layer coating solution used in Example 1 was changed to the following.

[Coating liquid for surface protective layer]
Low molecular charge transport material of structural formula (B) 3 parts by weight Charge transport material of structural formula (A) 0.5 part by weight Silicone modified fluororesin (ZX-007C, manufactured by Fuji Kasei Kogyo Co., Ltd.)
10.0 parts by weight (solid content: 3.5 parts by weight)
Melamine resin (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals)
5.8 parts by weight (solid content: 3.5 parts by weight)
Tetrahydrofuran 150 parts by weight Cyclohexanone 50 parts by weight

A photoconductor was prepared in the same manner as in Example 1 except that the surface protective layer coating solution used in Example 1 was changed to the following.

[Coating liquid for surface protective layer]
Low molecular charge transport material of the structural formula (B) 3 parts by weight siloxane-based condensate (NSC 2319, manufactured by Nippon Seika Co., Ltd.) 7 parts by weight leveling agent (BYK-Sicilan 3700, manufactured by Big Chemie)
1 part by weight tetrahydrofuran 150 parts by weight cyclohexanone 50 parts by weight

A photoconductor was prepared in the same manner as in Example 1 except that the surface protective layer coating solution used in Example 1 was changed to the following.

[Coating liquid for surface protective layer]
Low molecular charge transport material of structural formula (B) 3 parts by weight melamine resin (Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals, Inc.)
12 parts by weight tetrahydrofuran 180 parts by weight cyclohexanone 50 parts by weight

  An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the coating liquid for surface protective layer shown below was applied and changed to dry at 140 ° C. for 20 minutes.

[Coating liquid for surface protective layer]
3.8 parts of polycarbonate resin (Iupilon Z200: manufactured by Mitsubishi Gas Chemical Company)
Charge transport material of structural formula (A) 2.8 parts α-alumina fine particles 2.6 parts (specific resistance: 2.5 × 10 12 Ω · cm, average primary particle size: 0.5 μm)
Cyclohexanone 80 parts Tetrahydrofuran 280 parts

  An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the coating liquid for surface protective layer shown below was applied and changed to dry at 140 ° C. for 20 minutes.

[Coating liquid for surface protective layer]
3.8 parts of polycarbonate resin (Iupilon Z200: manufactured by Mitsubishi Gas Chemical Company)
2.8 parts of charge transport material of structural formula (A) 2.6 parts of fine silica powder (specific resistance: 4 × 10 13 Ω · cm, average primary particle size: 0.3 μm)
Cyclohexanone 80 parts Tetrahydrofuran 280 parts

  An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the coating liquid for surface protective layer shown below was applied and changed to dry at 140 ° C. for 20 minutes.

[Coating liquid for surface protective layer]
3.8 parts of polycarbonate resin (Iupilon Z200: manufactured by Mitsubishi Gas Chemical Company)
2.8 parts of charge transport material of structural formula (A) 2.6 parts of titanium oxide fine particles (specific resistance: 1.5 × 10 10 Ω · cm, average primary particle size: 0.5 μm)
Cyclohexanone 80 parts Tetrahydrofuran 280 parts

  An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the coating liquid for surface protective layer shown below was applied and changed to dry at 140 ° C. for 20 minutes.

[Coating liquid for surface protective layer]
3.8 parts of polycarbonate resin (Iupilon Z200: manufactured by Mitsubishi Gas Chemical Company)
2.8 parts of tin oxide-antimony oxide powder 2.6 parts (specific resistance: 106 Ω · cm, average primary particle size 0.4 μm)
Cyclohexanone 80 parts Tetrahydrofuran 280 parts

  An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the coating liquid for surface protective layer shown below was applied and changed to dry at 140 ° C. for 20 minutes.

[Coating liquid for surface protective layer]
Polymer charge transport material of structural formula (C) 6.6 parts α-alumina fine particles 2.6 parts (specific resistance: 2.5 × 10 12 Ω · cm, average primary particle size: 0.5 μm)
Cyclohexanone 120 parts Tetrahydrofuran 420 parts

The obtained electrophotographic photosensitive member was mounted on a process cartridge for an electrophotographic apparatus as shown in FIG.
It is mounted on an electrophotographic image forming apparatus (image MF-2200 manufactured by Ricoh Co., Ltd.) that uses a semiconductor laser of 780 nm as the image exposure means and a contact roller charger as the charging means, and A4 size PPC paper is fed in the vertical direction. The dark portion potential Vd and the light portion potential Vl were measured before and after 100,000 sheets were passed, and image evaluation was performed. In the image evaluation, the presence / absence of cleaning failure when a halftone image was output was visually measured. The results are shown in Table 3.

It is sectional drawing which shows the structural example of the electrophotographic photoreceptor used for this invention. 1 is a schematic view of an electrophotographic process and an electrophotographic image forming apparatus of the present invention. 1 is a schematic view of an image forming apparatus including a plurality of image forming elements of the present invention. FIG. 2 is a schematic view of a process cartridge having the photoreceptor of the present invention. It is explanatory drawing of the X-ray-diffraction spectrum of the titanyl phthalocyanine powder used for the photoreceptor of this invention.

Explanation of symbols

1C, 1M, 1Y, 1K Photoconductor 2C, 2M, 2Y, 2K Charging member 3C, 3M, 3Y, 3K Laser light 4C, 4M, 4Y, 4K Developing member 5C, 5M, 5Y, 5K Cleaning member 6C, 6M, 6Y , 6K image forming element 7 transfer paper 8 feeding roller 9 registration roller 10 transfer conveying belt 11C, 11M, 11Y, 11K transfer brush 12 fixing device 17 charging member 31 conductive support 33 intermediate layer 35 charge generation layer 37 charge transport layer DESCRIPTION OF SYMBOLS 39 Protective layer 41 Photoconductor 42 Static elimination lamp 43 Charging roller 45 Image exposure part 46 Developing unit 47 Charger before transfer 48 Registration roller 49 Transfer paper 50 Transfer charger 51 Separation charger 52 Separation claw 53 Charger before cleaning 54 Fur brush 55 Cleaning brush and cleaning Blade 56 Developing roller 57 Transfer roller

Claims (11)

Formed on a conductive support from a charge generation layer containing at least a phthalocyanine pigment having an average particle size of 0.3 μm or less and a benzoquinone derivative represented by the following structural formula, and a charge transport layer coating solution containing a tetrahydrofuran solvent An electrophotographic photosensitive member comprising a charge transport layer and a surface protective layer provided in this order.

Formula (II)
(In the formula (II), R1 to R4 each independently represent a hydrogen atom, an alkyl group,
Represents any one of an alkoxy group, an aryl group, an aralkyl group, and a halogen group)   R1 to R4 of the benzoquinone derivative represented by the formula (II) contained in the charge generation layer containing the phthalocyanine pigment are each independently a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group. Any one of the halogen groups and a benzoquinone derivative (I-II) in which at least one of the R1 to R4 groups of the benzoquinone derivative represented by the formula (II) is a halogen group The electrophotographic photosensitive member according to claim 1, comprising:   3. The electrophotographic photosensitive member according to claim 1, wherein the content of the benzoquinone derivative is 1 to 30 wt% of the phthalocyanine pigment.   The surface protective layer is formed by a crosslinking reaction of at least a crosslinkable charge transport material containing a reactive hydroxyl group, a thermosetting resin monomer, and a thermosetting surfactant, and contains the crosslinkable charge transport material. 2. The electrophotographic photosensitive member according to claim 1, wherein the amount is 7.5 wt% or more of the surface protective layer.   5. The electrophotographic photoreceptor according to claim 4, wherein the thermosetting resin monomer is an amino resin alone or an amino resin mixture.   The thermosetting surfactant contains at least one of a copolymer of alkyl fluoride and acrylic acid, a copolymer of silicone and acrylic acid, and a reactive hydroxyl group-containing fluororesin grafted with a silicone segment. The electrophotographic photosensitive member according to claim 4.   The phthalocyanine pigment contained in the charge generation layer is a titanyl phthalocyanine pigment having a maximum peak at 27.2 ± 0.2 ° in a Bragg angle 2θ in Cu-Kα rays. 4. The electrophotographic photosensitive member according to any one of items 3.   The titanyl phthalocyanine has a maximum peak at 27.2 ± 0.2 ° at a Bragg angle 2θ of the Cu—Kα line, and further has a peak at a minimum angle of 7.3 ± 0.2 °, 7.4-9 The electrophotographic photosensitive member according to claim 7, wherein the electrophotographic photosensitive member does not have a peak in a range of 4 °.   The electrophotographic photosensitive member according to claim 7 or 8, wherein the titanyl phthalocyanine further has no peak at 26.3 °.   An image forming apparatus on which an image forming element comprising at least a charging means, an image exposing means, a developing means, a transferring means and an electrophotographic photosensitive member is mounted, wherein the electrophotographic photosensitive member is defined in claims 1 to 9. An image forming apparatus comprising the electrophotographic photosensitive member according to any one of the above.   A process cartridge comprising at least an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is the photosensitive member according to claim 1.

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