JP4099136B2 - Electrophotographic photoreceptor - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member used for a laser beam printer, a facsimile, a digital copy or the like, a manufacturing method thereof, an image forming apparatus using the electrophotographic photosensitive member, and a process cartridge.

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.

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. However, when a photoreceptor is prepared using a coating solution for a charge transport layer using a non-halogen solvent, there is no particular problem in the initial stage, but when it is mounted on an electrophotographic apparatus and used for a long time. In other words, defects such as black spots, fogging, etc., become noticeable gradually.
Causes of image defects caused by this long-term use include an increase in charge injection from the conductive support, a decrease in chargeability due to the material of the charge generation material and the charge transport material, or wear of the charge transport layer. And other factors such as an electric field rise in the photosensitive layer.

In order to solve such an abnormal image, a method has been proposed in which the intermediate layer contains a metal oxide and has a specific surface roughness to prevent an increase in charge injection from the conductive support. (For example, refer to Patent Document 3).
However, in this method as well, when an electrophotographic photosensitive member is produced using a coating solution for a charge transport layer using a non-halogen solvent, there is no particular problem in the initial stage. When used for a long time, there was a problem that defects on the image, such as black spots and fogging, gradually became conspicuous.

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, see Patent Document 4).
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 5 and 6).
However, even when this method is used to produce a photoreceptor using a charge transport layer coating solution using a non-halogen solvent, there is a problem that abnormal images are generated due to repeated use.

As a method for preventing image defects such as black spots and fog by preventing an electric field increase in the photosensitive layer caused by wear of the charge transport layer, an organometallic polycondensation matrix formed from an organometallic compound is used. There has been proposed a method of obtaining an electrophotographic photoreceptor having high mechanical strength and high wear resistance by providing a protective layer containing a component and a charge transport material (see, for example, Patent Document 7).
However, even in this method, when a photoreceptor is produced using a coating solution for a charge transport layer using a non-halogen solvent, the durability is not sufficiently improved, and abnormal images associated with repeated use are not obtained. There was a bug that occurred.

In addition, it contains specific charge generation materials, and after applying the charge transport layer, it is dried at a temperature of 140 ° C or higher to prevent image defects such as black spots and fog, especially in high-temperature and high-humidity environments. However, a method for obtaining a photoconductor with little wear during repeated use has been proposed.
However, this method is not effective in the case where an intermediate layer composed of an inorganic pigment and a thermosetting resin is provided, and has a defect that defects on the image such as black spots and fogging are caused by repeated use. Is.

  In addition, by providing an intermediate layer made of a specific material, a photoconductor with good durability even after repeated use has been proposed, but the solvent and drying temperature used when preparing the charge transport layer are different. As a factor, the finally obtained photoreceptor can easily form images such as black spots and fog (for example, see Patent Document 9).

JP-A-61-204642 Japanese Patent Laid-Open No. 62-280864 JP-A-11-202517 JP-A-9-269606 JP 2000-89493 A JP 2001-109178 A JP-A-9-222746 JP 2002-109773 A JP 2002-107974 A

  An object of the present invention is to provide a highly durable electrophotographic photosensitive member manufacturing method capable of obtaining a good image free of abnormal images such as black spots and fogging even in repeated use over a long period of time in consideration of the above situation, and An electrophotographic photosensitive member using the same, and an electrophotographic apparatus and a process cartridge including the electrophotographic photosensitive member are provided.

  The present inventors have an intermediate layer composed of the above inorganic pigment and thermosetting resin, and when using a charge transport layer coating liquid containing tetrahydrofuran as a solvent, abnormal images such as black spots and fogging As a result of intensive studies on the problem of occurrence of the above problem, it has been found that the above problems can be solved by the following means.

That is, the above-mentioned problem is ( 1 ) “Electron in which an intermediate layer composed of at least an inorganic pigment and a thermosetting resin, a charge generation layer, a charge transport layer, and a surface protective layer are provided on a conductive support in this order It is a photographic photoreceptor, and the intermediate layer coating solution is applied on a conductive support, and then dried at a temperature of 110 to 140 ° C., and the charge transport layer coating solution containing tetrahydrofuran as a solvent is used as the charge generation layer. after coating the above, and dried at a drying temperature below the temperature of the intermediate layer, after coating the surface protective layer on the charge transport layer state, and are those obtained by drying at a drying temperature below the temperature of the intermediate layer, wherein electrophotographic photoreceptor binder resin of the surface protective layer and said resin der Rukoto obtained by crosslinking reaction between the fluorine-based surfactant and a thermosetting resin monomer containing a reactive hydroxyl group ", (2 ) "The binder resin of the surface protective layer is reactive hydroxide Wherein characterized in that it is a resin obtained by a crosslinking reaction between the fluorine-based surfactant and a melamine containing a group (1) electrophotographic photosensitive member according to claim ', (3) "binder of the surface protective layer The resin is obtained by a crosslinking reaction between a fluorosurfactant containing a reactive hydroxyl group, a charge transporting substance containing a reactive hydroxyl group, and a thermosetting resin monomer ( 1 Or the electrophotographic photosensitive member according to the item (2) .

  According to the present invention, a method for producing a good electrophotographic photosensitive member that does not cause black spots or fogging even after repeated use over a long period of time, an electrophotographic photosensitive member using the same, and an electrophotographic image using the electrophotographic photosensitive member An apparatus and a process cartridge for an electrophotographic apparatus are provided.

Hereinafter, the present invention will be described in detail.
The inorganic pigment used in the intermediate layer of the present invention may be a commonly used pigment, but when white or a material with little absorption in visible light and near infrared light is considered to increase the sensitivity of the photoreceptor. desirable.
Examples thereof include white pigments such as titanium oxide, zinc white, zinc sulfate, lead white, and lithopone, and extender pigments such as aluminum oxide, silica, calcium carbonate, and barium sulfate. The ratio P / R between the inorganic pigment (P) and the binder resin (R) is preferably in the range of 0.1 / 1 to 5.0 / 1 by volume ratio. Of the inorganic pigments, titanium oxide is more preferable. This is because titanium oxide has a higher refractive index than other white pigments, is chemically and physically stable, has a large hiding power, and has a high whiteness. Titanium oxide includes rutile type and anatase type, any of which can be used. The aluminum oxide may be a commonly used aluminum oxide.

Among the above inorganic pigments, a mixture of titanium oxide and aluminum oxide is also preferable as well as titanium oxide.
According to the study by the present inventors, it has been found that the variation of the photoreceptor characteristics due to the environment becomes smaller by making the intermediate layer of the photoconductor an intermediate layer in which titanium oxide and aluminum oxide are mixed. This is presumably because the dispersion state of the resin is improved by making the inorganic pigment a mixture of titanium oxide and aluminum oxide, and the intermediate layer has an optimum resistance value.
The mixing method of titanium oxide and aluminum oxide may be mixing and dispersing both powders, and there is no particular designation of the mixing method. The particle size of titanium oxide and aluminum oxide is preferably from 0.1 to 10 μm. Among these, the particle size of 0.3 to 1 μm increases the dispersibility with the resin component and improves the electrophotographic characteristics. Therefore, it is particularly preferably used.

Furthermore, it is preferable to use titanium oxide with an untreated surface. As titanium oxide, titanium oxide that has been subjected to inorganic treatment such as alumina treatment or silica treatment for improving dispersibility, weather resistance, discoloration resistance and the like is commercially available.
However, it has been found that when such surface-treated titanium oxide is contained in the intermediate layer, the photoreceptor characteristics deteriorate at high temperature and high humidity or low temperature and low humidity due to the effect of the treatment. In order to reduce deterioration of the photoreceptor characteristics, it is preferable to use titanium oxide that has not been subjected to surface treatment.

The purity of titanium oxide is preferably 99.5% by weight or more. As an impurity of the inorganic pigment, there are hygroscopic materials such as Na ₂ O and K ₂ O. Although such impurities are very small, due to their hygroscopicity, the properties of titanium oxide are made environment dependent.
As a result, a photoreceptor in which the intermediate layer contains titanium oxide containing such impurities has an environment dependency of the photoreceptor characteristics. Therefore, by setting the purity of titanium oxide to 99.5% by weight or more, it is possible to further reduce the environmental fluctuation of the photoreceptor characteristics.

  The thermosetting resin constituting the intermediate layer is preferably a curable resin that forms a three-dimensional network structure such as polyurethane, melamine resin, phenol resin, alkyd-melamine resin, epoxy resin, etc., especially oil-free alkyd resin and butyl resin. A thermosetting resin obtained by thermally polymerizing a melamine resin is desirable.

Moreover, in this invention, after apply | coating the coating liquid for intermediate | middle layers on an electroconductive support body, by drying at the temperature of 110-140 degreeC, even if it uses repeatedly over a long period, abnormal images, such as black spots and fogging It has been found that it is possible to obtain a good image without any problem.
When the intermediate layer in which the thermosetting resin and the inorganic pigment are dispersed is dried at a temperature lower than 110 ° C., there is a problem in that the coating film is peeled off due to a decrease in adhesiveness with the conductive support. The reason why the above-described effects can be obtained is not clear, but when dried at a temperature higher than 140 ° C., volume shrinkage due to the progress of thermosetting and a decrease in volume resistance of the intermediate layer occur, and the conductive support. It is estimated that charge injection from

The intermediate layer of the photoreceptor of the present invention may further have a structure divided into two layers of a first intermediate layer and a second intermediate layer. In this case, the first intermediate layer formed on the conductive support is composed of a thermosetting resin in which the above-described inorganic pigment is dispersed.
Next, the second intermediate layer formed on the first intermediate layer is composed of N-alkoxymethylated polyamide or a crosslinked product of N-alkoxymethylated polyamide and melamine resin. By using this method, an increase in charge injection from the conductive support can be further prevented, and the entire intermediate layer can be thickened, so that abnormal images due to discharge breakdown can also be suppressed.

The N-alkoxymethylated polyamide used in the present invention is preferably used because the N-alkoxymethylated polyamide having an alkoxy group having 1 to 10 carbon atoms has good solubility in a solvent for preparing a coating solution. it can.
Examples of the N-alkoxymethylated polyamide having an alkoxy group having 1 to 10 carbon atoms include methoxymethylated polyamide, ethoxymethylated polyamide, and butoxymethylated polyamide.

  Although the substitution rate of the alkoxymethyl group of the N-alkoxymethylated polyamide used in the present invention is not particularly limited, since the solubility in a solvent is improved, the N-alkoxy having an alkoxymethylation rate (substitution rate) of 15 mol% or more. Methylated polyamide is more preferred.

  Of the above N-alkoxymethylated polyamides, methoxymethylated polyamides are preferred because they are readily available. As the methoxymethylated polyamide used in the present invention, polyamide 6, polyamide 12, or a copolymer polyamide containing these as a constituent component is proposed, for example, by TL Cairns (J. Am. Chem. Soc. 71. P651 (1949)). It can be obtained by denaturing by a method. The methoxymethylated polyamide is obtained by replacing the amide bond hydrogen of the original polyamide with a methoxymethyl group. This substitution rate can be selected in a wide range depending on the denaturing conditions.

  Regarding the melamine resin constituting the N-alkoxymethylated polyamide and the crosslinked product, a commercially available melamine resin can be used, and a butylated melamine resin is particularly desirable, and the use ratio of the N-alkoxymethylated polyamide and the melamine resin is as follows: Usually, 0.01 to 100 parts by weight of the melamine resin is good for 1 part by weight of the N-alkoxymethylated polyamide.

  As a method for forming the second intermediate layer, first, N-alkoxymethylated polyamide or N-alkoxymethylated polyamide and a melamine resin are dissolved in a lower aliphatic alcohol such as methanol, ethanol, propanol, and the second intermediate layer is applied. Prepare the solution. At this time, in order to promote crosslinking, it is desirable to make the second intermediate layer coating solution acidic. For this purpose, an organic acid such as maleic acid, citric acid, tartaric acid or succinic acid, or an inorganic acid such as boric acid or hypophosphorous acid may be added to the coating solution. The addition amount of these acidic catalysts is 0.1% to 10% based on the weight of the N-alkoxymethylated polyamide, or 0.1% to 10% based on the total weight of the N-alkoxymethylated polyamide and the melamine resin. %.

  The thickness of the second intermediate layer is preferably 0.01 to 1 μm. If it is too thin, the effect of suppressing abnormal images is small, and if it is too thick, the residual potential tends to increase.

Moreover, when drying after apply | coating the coating liquid for 2nd intermediate | middle layers on a 1st intermediate | middle layer, it is desirable to dry at the temperature below the drying temperature of 85 degreeC-1st intermediate | middle layer. When the second intermediate layer is dried at a temperature lower than 85 ° C., the crosslinking does not proceed completely, resulting in a large number of residual alkoxy groups and a large environmental dependency, and a decrease in adhesiveness with the first intermediate layer. The problem that peeling of the coating film to be seen is seen arises.
In addition, when the second intermediate layer is dried at a temperature that is particularly higher than the drying temperature of the first intermediate layer, the reason is not clear, but the volume shrinkage and volume resistance due to thermosetting of the first intermediate layer in the lowermost layer It is considered that the decrease in charge rapidly proceeds, the charge injection from the conductive support increases rapidly, and abnormal images such as black spots and fogging occur in repeated use over a long period of time.

  Examples of the charge generation material used in the present invention include a carbazole skeleton, a triphenylamine skeleton, a diphenylamine skeleton, a dibenzothiophene skeleton, a fluorenone skeleton, an oxadiazole skeleton, a bisstylbene skeleton, a distyryloxadiazole skeleton, a distyrylcarbazole skeleton, and the like. Azo pigments, phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, azulenium salt pigments, squaric acid methine pigments, perylene pigments, anthraquinone or polycyclic quinone pigments, quinoneimine pigments, diphenylmethane and triphenylmethane Organic pigments such as pigments, benzoquinone and naphthoquinone pigments, cyanine and azomethine pigments, indigoid pigments, and bisbenzimidazole pigments. , Or it can be used as a mixture of two or more. Among these, titanyl phthalocyanine (TiOPc), which is a metal phthalocyanine pigment and has titanium as a central metal represented by the following formula (1), is particularly desirable because of its high sensitivity and excellent characteristics.

（式中、Ｘ_１、Ｘ_２、Ｘ_３、Ｘ_４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 when it is repeatedly used without losing high sensitivity. Furthermore, the use of a crystal form having no peak at 26.3 ° among the above crystal forms can make the effects of the present invention more remarkable.

  Further, in the present invention, when the average particle size of the above-mentioned titanyl phthalocyanine pigment is 0.3 μm or less, the moving distance to the particle surface of the photocarrier generated inside the charge generation material particle is shortened, and the probability of deactivation This is more desirable because it exhibits particularly excellent sensitivity characteristics due to an increase in photocarrier injection efficiency based on a decrease in the surface area and an increase in the contact amount with the charge transport material surrounding the pigment particle surface as the surface area increases.

  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.

  Moreover, when drying after apply | coating the coating liquid for charge generation layers on an intermediate | middle layer, it is desirable to dry at the temperature below 60 degreeC-the drying temperature of an intermediate | middle layer. When the charge generation layer is dried at a temperature lower than 60 ° C., there arises a problem that peeling of the coating film due to a decrease in adhesion with the intermediate layer is observed. In addition, when the charge generation layer is dried at a temperature that is particularly higher than the drying temperature of the intermediate layer, the reason is not clear, but the volume shrinkage and the volume resistance due to the thermosetting of the intermediate layer in the lowermost layer are rapidly reduced. The charge injection from the conductive support increases rapidly, and abnormal images such as black spots and fogging occur in repeated use over a long period of time. Furthermore, the above-mentioned titanyl phthalocyanine pigment is desirably dried at 120 ° C. or less from the viewpoint of crystal stability.

  As the coating solvent used for forming the charge transport layer of the present invention, a coating solution for charge transport layer containing tetrahydrofuran is desirable since it has a small environmental load and exhibits excellent solubility and coating properties.

In addition, when the charge transport layer coating liquid is applied on the charge generation layer and then dried, it is desirable to dry at a temperature not higher than 100 ° C. to the drying temperature of the intermediate layer. When the charge transport layer is dried at a temperature lower than 100 ° C., there arises a problem that the residual potential rises during repeated use, which is considered to be caused by residual tetrahydrofuran.
Also, when the charge transport layer is dried at a temperature that is particularly high compared to the drying temperature of the intermediate layer, the reason is not clear, but the volume shrinkage and the volume resistance due to the thermosetting of the intermediate layer in the lowermost layer are rapidly reduced. The charge injection from the conductive support increases rapidly, and abnormal images such as black spots and fogging occur in repeated use over a long period of time.

  In the present invention, a method of providing a surface protective layer is also effective in order to prevent an electric field increase in the photosensitive layer caused by wear of the charge transport layer. As the surface protective layer, 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.

Also in these, when the surface protective layer coating solution is applied on the charge transport layer and then dried, it is desirable to dry at a temperature not lower than 100 ° C. and not higher than the drying temperature of the intermediate layer. When the surface protective layer is dried at a temperature lower than 100 ° C., problems such as an increase in the residual potential, which may be caused by the residual solvent, and insufficient curing of the resin due to insufficient use of the resin occur.
In addition, when the surface protective layer is dried at a temperature that is particularly high compared to the drying temperature of the intermediate layer, the reason is not clear, but the volume shrinkage and volume resistance due to the thermosetting of the intermediate layer in the lowermost layer are rapidly reduced. The charge injection from the conductive support increases rapidly, and abnormal images such as black spots and fogging occur in repeated use over a long period of time.

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) and a charge generation layer mainly composed of a charge generation material. (35) and the charge transport layer (37) mainly composed of the charge transport material have a laminated structure.
FIG. 2 is another cross-sectional view showing a configuration example of the electrophotographic photosensitive member used in the present invention. On the conductive support (31), the first intermediate layer (33) and the second intermediate layer (34). The charge generation layer (35) mainly composed of the charge generation material and the charge transport layer (37) mainly composed of the charge transport material are laminated.
FIG. 3 is a sectional view showing still another structural example of the electrophotographic photosensitive member used in the present invention. On the conductive support (31), the intermediate layer (33) and the charge generation layer (35) are shown. The charge transport layer (37) is provided, and the protective layer (39) is laminated thereon.

As the conductive support (31), a material having a volume resistance of 10 ¹⁰ Ω · cm or less, for example, a metal such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, oxidation Metal oxide such as indium by vapor deposition or sputtering, film or cylindrical plastic, paper coated, or aluminum, aluminum alloy, nickel, stainless steel plates, etc. and methods such as extrusion and drawing And an endless nickel belt described in JP-A-52-36016, an endless stainless steel belt, and the like, and a method of forming a continuous roughness by cutting the surface of these with a cutting tool, Liquid honing, superfinishing, wet or dry blasting, or anodic oxide film formation Those subjected to surface roughening by means of, for example, are also used favorably.

  As the intermediate layer composed of the inorganic pigment and the thermosetting resin used in the electrophotographic photoreceptor of the present invention, those mentioned above are preferably used. As the solvent used here, for example, non-halogen solvents such as methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, cyclohexane, toluene, xylene, and ligroin are desirable. . These intermediate layers can be added with additives and the like, and the film thickness is suitably 0.5 to 10 μm.

  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 for the coating solution, a dip coating method, spray coating, beat coating, nozzle coating, spinner coating, ring coating, or the like can be used. In addition, when the second intermediate layer intermediate layer composed of a cross-linked N-alkoxymethylated polyamide or a cross-linked product of N-alkoxymethylated polyamide and melamine resin is provided, the above-described method is favorably used.

Next, the photosensitive layer will be described.
As described above, as the photosensitive layer, a 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-mentioned organic pigment as a charge generation material in a solvent together with an appropriate resin, applying this onto a conductive support, and drying. As the method and the coating method, the above-described methods can be used.

  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) is a non-halogen solvent, preferably a cyclic ether such as tetrahydrofuran, dioxolane or dioxane, an aromatic hydrocarbon such as toluene or xylene, and the like. It can be formed by dissolving or dispersing in these derivatives and applying and drying this on the charge generation layer. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.

  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 addition, a polymer charge transport material having a function as a charge transport material and a function of a binder resin is also preferably used for the charge transport layer. The charge transport layer composed of these polymer charge transport materials is excellent in wear resistance. Improving the wear resistance reduces the increase in the electric field strength applied to the photoreceptor in repeated use, and makes the effect of the present invention even more remarkable. As the polymer charge transporting material, known materials can be used, but polycarbonates having a triarylamine structure as shown in the following structural formulas (2) to (11) in the main chain and / or side chain are favorably used. .

式中、Ｒ_１，Ｒ_２，Ｒ_３はそれぞれ独立して置換もしくは無置換のアルキル基又はハロゲン原子、Ｒ_４は水素原子又は置換もしくは無置換のアルキル基、Ｒ_５，Ｒ_６は置換もしくは無置換のアリール基、ｏ，ｐ，ｑはそれぞれ独立して０〜４の整数、ｋ，ｊは組成を表わし、０．１≦ｋ≦１、０≦ｊ≦０．９、ｎは繰り返し単位数を表わし５〜５０００の整数である。Ｘは脂肪族の２価基、環状脂肪族の２価基、または下記一般式で表わされる２価基を表わす。

In the formula, R ₁ , R ₂ and R ₃ are each independently a substituted or unsubstituted alkyl group or a halogen atom, R ₄ is a hydrogen atom or a substituted or unsubstituted alkyl group, and R ₅ and R ₆ are substituted or unsubstituted. Substituted aryl group, o, p, q are each independently an integer of 0-4, k, j are compositions, 0.1 ≦ k ≦ 1, 0 ≦ j ≦ 0.9, n is the number of repeating units Represents an integer of 5 to 5000. X represents an aliphatic divalent group, a cycloaliphatic divalent group, or a divalent group represented by the following general formula.

式中、Ｒ_１０１，Ｒ_１０２は各々独立して置換もしくは無置換のアルキル基、アリール基またはハロゲン原子を表わす。ｌ、ｍは０〜４の整数、Ｙは単結合、炭素原子数１〜１２の直鎖状、分岐状もしくは環状のアルキレン基、−Ｏ−，−Ｓ−，−ＳＯ−，−ＳＯ_２−，−ＣＯ−，−ＣＯ−Ｏ−Ｚ−Ｏ−ＣＯ−（式中、Ｚは脂肪族の２価基を表わす。）または、

In the formula, R ₁₀₁ and R ₁₀₂ each independently represents a substituted or unsubstituted alkyl group, aryl group or halogen atom. l and m are integers of 0 to 4, Y is a single bond, a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms, —O—, —S—, —SO—, —SO ₂ —. , —CO—, —CO—O—Z—O—CO— (wherein Z represents an aliphatic divalent group), or

（式中、ａは１〜２０の整数、ｂは１〜２０００の整数、Ｒ_１０３、Ｒ_１０４は置換または無置換のアルキル基又はアリール基を表わす。）を表わす。ここで、Ｒ_１０１とＲ_１０２，Ｒ_１０３とＲ_１０４は、それぞれ同一でも異なってもよい。

(Wherein, a represents an integer of 1 to 20, b represents an integer of 1 to 2000, and R ₁₀₃ and R ₁₀₄ represent a substituted or unsubstituted alkyl group or an aryl group). Here, R ₁₀₁ and R ₁₀₂ , R ₁₀₃ and R ₁₀₄ may be the same or different.

式中、Ｒ_７，Ｒ_８は置換もしくは無置換のアリール基、Ａｒ_１，Ａｒ_２，Ａｒ_３は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、式（２）の場合と同じである。

In the formula, R ₇ and R ₈ represent a substituted or unsubstituted aryl group, and Ar ₁ , Ar ₂ , and Ar ₃ represent the same or different arylene groups. X, k, j, and n are the same as in the case of Expression (2).

式中、Ｒ_９、Ｒ_１０は置換もしくは無置換のアリール基、Ａｒ_４，Ａｒ_５，Ａｒ_６は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、式（２）の場合と同じである。

In the formula, R ₉ and R ₁₀ represent a substituted or unsubstituted aryl group, and Ar ₄ , Ar ₅ , and Ar ₆ represent the same or different arylene groups. X, k, j, and n are the same as in the case of Expression (2).

式中、Ｒ_１１、Ｒ_１２は置換もしくは無置換のアリール基、Ａｒ_７、Ａｒ_８、Ａｒ_９は同一又は異なるアリレン基、ｐは１〜５の整数を表わす。Ｘ，ｋ，ｊおよびｎは、式（２）の場合と同じである。

In the formula, R ₁₁ and R ₁₂ are substituted or unsubstituted aryl groups, Ar ₇ , Ar ₈ and Ar ₉ are the same or different arylene groups, and p represents an integer of 1 to 5. X, k, j, and n are the same as in the case of Expression (2).

式中、Ｒ_１３，Ｒ_１４は置換もしくは無置換のアリール基、Ａｒ_１０，Ａｒ_１１，Ａｒ_１２は同一又は異なるアリレン基、Ｘ_１，Ｘ_２は置換もしくは無置換のエチレン基、又は置換もしくは無置換のビニレン基を表わす。Ｘ，ｋ，ｊおよびｎは、式（２）の場合と同じである。

In the formula, R ₁₃ and R ₁₄ are substituted or unsubstituted aryl groups, Ar ₁₀ , Ar ₁₁ and Ar ₁₂ are the same or different arylene groups, X ₁ and X ₂ are substituted or unsubstituted ethylene groups, or substituted or unsubstituted Represents a substituted vinylene group. X, k, j, and n are the same as in the case of Expression (2).

式中、Ｒ_１５，Ｒ_１６，Ｒ_１７，Ｒ_１８は置換もしくは無置換のアリール基、Ａｒ_１３，Ａｒ_１４，Ａｒ_１５，Ａｒ_１６は同一又は異なるアリレン基、Ｙ_１，Ｙ_２，Ｙ_３は単結合、置換もしくは無置換のアルキレン基、置換もしくは無置換のシクロアルキレン基、置換もしくは無置換のアルキレンエーテル基、酸素原子、硫黄原子、ビニレン基を表わし同一であっても異なってもよい。Ｘ，ｋ，ｊおよびｎは、式（２）の場合と同じである。

In the formula, R ₁₅ , R ₁₆ , R ₁₇ and R ₁₈ are substituted or unsubstituted aryl groups, Ar ₁₃ , Ar ₁₄ , Ar ₁₅ and Ar ₁₆ are the same or different arylene groups, and Y ₁ , Y ₂ and Y ₃ are A single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group may be the same or different. X, k, j, and n are the same as in the case of Expression (2).

式中、Ｒ_１９，Ｒ_２０は水素原子、置換もしくは無置換のアリール基を表わし、Ｒ_１９とＲ_２０は環を形成していてもよい。Ａｒ_１７，Ａｒ_１８，Ａｒ_１９は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、式（２）の場合と同じである。

In the formula, R ₁₉ and R _{20 each} represent a hydrogen atom or a substituted or unsubstituted aryl group, and R ₁₉ and R ₂₀ may form a ring. Ar ₁₇ , Ar ₁₈ and Ar ₁₉ represent the same or different arylene groups. X, k, j, and n are the same as in the case of Expression (2).

式中、Ｒ_２１は置換もしくは無置換のアリール基、Ａｒ_２０，Ａｒ_２１，Ａｒ_２２，Ａｒ_２３は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、式（２）の場合と同じである。

In the formula, R ₂₁ represents a substituted or unsubstituted aryl group, and Ar ₂₀ , Ar ₂₁ , Ar ₂₂ , and Ar ₂₃ represent the same or different arylene groups. X, k, j, and n are the same as in the case of Expression (2).

式中、Ｒ_２２，Ｒ_２３，Ｒ_２４，Ｒ_２５は置換もしくは無置換のアリール基、Ａｒ_２４，Ａｒ_２５，Ａｒ_２６，Ａｒ_２７，Ａｒ_２８は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、式（２）の場合と同じである。

In the formula, R ₂₂ , R ₂₃ , R ₂₄ and R ₂₅ represent a substituted or unsubstituted aryl group, and Ar ₂₄ , Ar ₂₅ , Ar ₂₆ , Ar ₂₇ and Ar ₂₈ represent the same or different arylene groups. X, k, j, and n are the same as in the case of Expression (2).

式中、Ｒ_２６，Ｒ_２７は置換もしくは無置換のアリール基、Ａｒ_２９，Ａｒ_３０，Ａｒ_３１は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、式（２）の場合と同じである。

In the formula, R ₂₆ and R ₂₇ represent a substituted or unsubstituted aryl group, and Ar ₂₉ , Ar ₃₀ and Ar ₃₁ represent the same or different arylene groups. X, k, j, and n are the same as in the case of Expression (2).

  Further, as the polymer charge transport material used in the charge transport layer, in addition to the polymer charge transport material described above, in the state of the monomer or oligomer having an electron donating group at the time of film formation of the charge transport layer, A polymer having a two-dimensional or three-dimensional crosslinked structure is finally included by carrying out a curing reaction or a crosslinking reaction.

  Examples of other polymers having an electron donating group include copolymers of known monomers, block polymers, graft polymers, star polymers, and, for example, JP-A-3-109406, JP-A-2000- It is also possible to use a crosslinked polymer having an electron donating group as described in JP-A-206723, JP-A No. 2001-34001, and the like.

  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, it is also an effective means to provide a protective layer (39) on the photosensitive layer for the purpose of preventing abnormal images such as black spots and fogging.
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, polyallyl. Sulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyarylate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, Examples include resins such as polyurethane, polyvinyl chloride, polyvinylidene chloride, and epoxy resins, fluorine resins such as polytetrafluoroethylene, and silicone resins. It is. 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 and indium, silica, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, tin oxide doped with antimony, tin doped indium oxide and other metals 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 which 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 filler type to be used and the electrophotographic process conditions using the photoreceptor, but the ratio of filler to the total solid content on the outermost layer side of the protective layer is preferably 5% by weight or more, preferably It is 10% by weight or more and 50% by weight or less, preferably about 30% by weight or less.
Further, the volume average particle size of the filler 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 device, 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 10 ⁶ 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 mixing 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 has poor chemical reactivity compared to a low molecule, and has a high resistance to an oxidizing gas generated from a charging member, or a high resistance to a sputtering effect caused by a discharge. When the surface has a highly wear-resistant film such as a protective layer, 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.

Further, in the present invention, in order to improve the reduction of the surface energy of the protective layer, a method using a resin obtained by crosslinking a fluorosurfactant having a reactive hydroxyl group as a crosslinking resin is an effective means. .
Examples of the crosslinked resin that can be used in the present invention include acrylic resins, urethane resins, melamine resins, alkyd resins, and the like, and melamine resins are particularly preferably used.
Moreover, a well-known material can be used for the fluorine-type surfactant in this invention. For example, as a copolymer containing (1) (meth) acrylate having a fluoroalkyl group described in JP-A-07-068398 [0017], for example, JP-A-60-212410 and JP-A-60- A block copolymer composed of a fluorine-free vinyl-type monomer and a fluorine-containing vinyl-type monomer described in JP-A-228588, and (2) a fluorine-based graft polymer such as polymethyl described in JP-A-60-187721 Examples thereof include a comb-type graft polymer obtained by copolymerizing a methacrylate macromonomer having a side chain with a methacrylate 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 the fluorine-containing block copolymer, Modiper F series (for example, F100, F110, F200, commercially available from Nippon Oil & Fats Co., Ltd.) as a block copolymer comprising a fluoroalkyl group-containing polymer segment and an acrylic polymer segment. F210, F2020).
Fluorine-based graft polymers are commercially available from Toa Gosei Co., Ltd. under the names Aron GF-150 and GF-300.
Further, when a crosslinkable resin is used, it is necessary to bond a charge transporting functional group to the crosslinkable resin to the extent that photoinduced charge carriers can move in the protective layer, or to incorporate a polymer charge transport material. . If it is possible to mix the low molecular charge transport material and the cross-linked resin, the low molecular charge transport material may be mixed, but it cannot be fixed in the protective layer, and the low molecular component is on the surface. May precipitate. By using the above-described polymer charge transport material for such a case, precipitation can be prevented and sensitivity characteristics can be improved.

Next, an electrophotographic image forming apparatus equipped with the novel electrophotographic photosensitive member of the present invention will be described in detail.
FIG. 4 is a schematic view for explaining the electrophotographic process and the electrophotographic image forming apparatus of the present invention.
In FIG. 4, 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. Although the photoconductor (41) has a drum shape, it may be a sheet or an endless belt. A charging roller (43), a pre-transfer charger (47), a transfer charger (50), a separation charger (51), and a pre-cleaning charger (53) include a corotron, a scorotron, a solid state charger, and charging. Known means such as a roller and a transfer roller 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.

Further, light sources such as an image exposure unit (45) and a static elimination lamp (42) include fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light emitting diodes (LEDs), semiconductor lasers (LD), electroluminescence (EL). ) And other luminescent materials 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 have a long wavelength light of 600 to 800 nm. Therefore, the phthalocyanine pigment, which is the above-mentioned 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 in combination with 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 but remains on the photoconductor (41). Toner is also produced. 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 is obtained, and if developed with toner of positive (negative) polarity, a negative image is 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. 5 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. 5, reference numeral (1C, 1M, 1Y, 1K) denotes a drum-shaped photoconductor, and this photoconductor (1C, 1M, 1Y, 1K) rotates in the direction of the arrow in the figure and rotates at least around it. A charging member (2C, 2M, 2Y, 2K), a developing member (4C, 4M, 4Y, 4K), and a cleaning member (5C, 5M, 5Y, 5K) are arranged in this order. The charging members (2C, 2M, 2Y, 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) from the back side of the photoreceptor between the charging member (2C, 2M, 2Y, 2K) and the developing member (4C, 4M, 4Y, 4K) , And an electrostatic latent image is formed on the photoreceptor (1C, 1M, 1Y, 1K). Then, four image forming elements (6C, 6M, 6Y, 6K) centering on such a photoreceptor (1C, 1M, 1Y, 1K) are along a transfer conveyance belt (10) which is a transfer material conveyance means. Are juxtaposed. The transfer / conveying belt (10) is provided between the developing member (4C, 4M, 4Y, 4K) and the cleaning member (5C, 5M, 5Y, 5K) of each image forming unit (6C, 6M, 6Y, 6K). 1C, 1M, 1Y, 1K), and a transfer brush (11C, 11M, 11Y, 11K) for applying a transfer bias to the back surface (back surface) of the transfer conveyance belt (10) that contacts the back side of the photoconductor. Is arranged. Each image forming element (6C, 6M, 6Y, 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. 5, the image forming operation is performed as follows. First, in each image forming element (6C, 6M, 6Y, 6K), the charging member (2C, 2M, 2Y) in which the photoconductor (1C, 1M, 1Y, 1K) rotates in the direction of the arrow (direction along with the photoconductor). , 2K), and then an electrostatic latent image corresponding to each color image to be created by laser light (3C, 3M, 3Y, 3K) by an exposure unit (not shown) disposed inside the photoconductor. It is formed.

Next, the latent image is developed by the developing members (4C, 4M, 4Y, 4K) to form a toner image. The developing members (4C, 4M, 4Y, 4K) are developing members that perform development with toners of C (cyan), M (magenta), Y (yellow), and K (black), respectively. 1M, 1Y, 1K) toner images of the respective colors are superimposed on the transfer paper.
The transfer paper (7) is fed out from the tray by a paper feed roller (8), temporarily stopped by a pair of registration rollers (9), and is transferred to the transfer conveyance belt (10) in synchronization with the image formation on the photosensitive member. Sent. The transfer paper (7) held on the transfer / conveying 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). It is.
The toner image on the photosensitive member is transferred onto the transfer paper (by the electric field formed by the potential difference between the transfer bias applied to the transfer brush (11C, 11M, 11Y, 11K) and the photosensitive member (1C, 1M, 1Y, 1K). 7) Transferred on top. Then, the recording paper (7) on which the toner images of four colors are superimposed 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 respective photoconductors (1C, 1M, 1Y, 1K) without being transferred by the transfer unit is collected by the cleaning device (5C, 5M, 5Y, 5K).

In the example of FIG. 5, 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 paper 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 FIG. 5, the charging member is in contact with the photosensitive member, but by providing an appropriate gap (about 10 to 200 μm) between them, the wear amount of both can be reduced and the toner film on the charging member can be reduced. It can be used satisfactorily with less ming.

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.
There are many shapes and the like of the process cartridge, but a general example is shown in FIG.

Hereinafter, although an example is given and the present invention is explained, the present invention is not restricted by an example. All parts are parts by weight.
( Reference Example 1)
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%)
: Dainippon Ink and Chemicals}
Melamine resin 10 parts {Super Becamine L-121-60 (solid content 60%)
: Dainippon Ink and Chemicals}
100 parts of methyl ethyl ketone

Next, titanyl phthalocyanine was synthesized 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 while 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]
15 parts of titanyl phthalocyanine pigment of Synthesis Example 1 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 125 ° C. for 20 minutes to form a charge transport layer having a thickness of 25 μm, thereby preparing an electrophotographic photosensitive member.
[Charge transport layer coating solution]
Polycarbonate (Iupilon Z200: Mitsubishi Gas Chemical Co., Ltd. 10 parts Charge transport material of the following structural formula (12) 8 parts Tetrahydrofuran 80 parts

( Reference Example 2)
An electrophotographic photosensitive member was produced in the same manner as in Reference Example 1 except that the drying temperature of the intermediate layer was changed to 140 ° C.

(Comparative Example 1)
An electrophotographic photosensitive member was produced in the same manner as in Reference Example 1 except that the drying temperature of the intermediate layer was changed to 155 ° C.

(Comparative Example 2)
An electrophotographic photosensitive member was produced in the same manner as in Reference Example 1 except that the drying temperature of the intermediate layer was changed to 110 ° C.

( Reference Example 3)
An electrophotographic photosensitive member was produced in the same manner as in Reference Example 1 except that the drying temperature of the intermediate layer was changed to 110 ° C. and the drying temperature of the charge transport layer was changed to 110 ° C.

(Comparative Example 3)
An electrophotographic photosensitive member was produced in the same manner as in Reference Example 1 except that the drying temperature of the intermediate layer was changed to 95 ° C.

(Comparative Example 4)
An electrophotographic photosensitive member was produced in the same manner as in Reference Example 1 except that the drying temperature of the charge transport layer was changed to 140 ° C.

( Reference Example 4)
An electrophotographic photosensitive member was produced in the same manner as in Reference Example 1 except that the drying temperature of the intermediate layer was changed to 140 ° C. and the drying temperature of the charge transport layer was changed to 140 ° C.

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. A 300,000 sheet passing test was conducted.
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.

( Reference Example 5)
The intermediate layer coating solution prepared in Reference Example 1 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 a first intermediate layer having a thickness of 2.8 μm. Subsequently, the following second intermediate layer coating solution prepared by dissolution was applied onto the first intermediate layer formed of the inorganic pigment-dispersed thermosetting resin, dried at 125 ° C. for 20 minutes, A second intermediate layer composed of a 25 μm crosslinked body was formed.
[Second intermediate layer coating solution]
Methoxymethylated polyamide (methoxymethylation ratio 30 mol%) 80 parts tartaric acid (10 weight% solids) 40 parts 700 parts n- butanol 300 parts Subsequently methanol, the charge generation layer in the same manner as in Reference Example 1, and a charge transport layer Then, an electrophotographic photosensitive member was produced.

( Reference Example 6)
An electrophotographic photosensitive member was produced in the same manner as in Reference Example 5 except that the drying temperature of the second intermediate layer was changed to 110 ° C.

(Comparative Example 5)
An electrophotographic photosensitive member was produced in the same manner as in Reference Example 5 except that the drying temperature of the second intermediate layer was changed to 140 ° C.

(Comparative Example 6)
An electrophotographic photosensitive member was produced in the same manner as in Reference Example 5 except that the drying temperature of the first intermediate layer was changed to 110 ° C.

(Comparative Example 7)
An electrophotographic photosensitive member was produced in the same manner as in Reference Example 5 except that the drying temperature of the first intermediate layer was changed to 110 ° C. and the drying temperature of the second intermediate layer was changed to 140 ° C.

( Reference Example 7 )
Except for changing the drying temperature of the first intermediate layer to 140 ° C. in the same manner as in Reference Example 5, to prepare an electrophotographic photoreceptor.

( Reference Example 8 )
An electrophotographic photosensitive member was produced in the same manner as in Reference Example 5 except that the drying temperature of the first intermediate layer was changed to 140 ° C. and the drying temperature of the second intermediate layer was changed to 110 ° C.

( Reference Example 9 )
An electrophotographic photosensitive member was produced in the same manner as in Reference Example 5 except that the drying temperature of the first intermediate layer was changed to 140 ° C. and the drying temperature of the second intermediate layer was changed to 140 ° C.

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. A 300,000 sheet passing test was conducted.
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.

( Reference Examples 10-14 , Comparative Examples 8-10)
Except that the second intermediate layer coating solution shown below the reference example 5-9, an electrophotographic photoreceptor was prepared in the same manner as in Comparative Example 5-7.
[Second intermediate layer coating solution]
Methoxymethylated polyamide (methoxymethylation rate 32 mol%) 50 parts Melamine resin 50 parts (Sumitex Resin M-3 (solid content 80% by weight) (manufactured by Sumitomo Chemical))
Tartaric acid (solid content 10% by weight) 60 parts Methanol 800 parts n-Butanol 250 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. A 300,000 sheet passing test was conducted.
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 3.

( Reference Examples 15-18 , Comparative Examples 11-14)
In Reference Examples 1 to 4 and Comparative Examples 1 to 4, electrophotographic photosensitive members were formed in the same manner except that the formation of the charge generation layer was changed to the following method.
5 parts by weight of butyral resin ESREC BMS (manufactured by Sekisui Chemical Co., Ltd.) was dissolved in 150 parts by weight of cyclohexanone, and 15 parts by weight of a trisazo pigment of the following structural formula (13) was added thereto and dispersed in a ball mill for 72 hours. Further, 210 parts by weight of cyclohexanone was added and dispersed for 5 hours. This was diluted with cyclohexanone while stirring so that the solid content was 1.0% by weight.
The charge generation layer coating solution thus obtained was applied to the intermediate layer and dried at 120 ° C. for 10 minutes to form a charge generation layer having a thickness of about 0.2 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. A 300,000 sheet passing test was conducted.
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 4.

( Reference Example 19 )
An electrophotographic photosensitive member was produced in the same manner as in Reference Example 1, except that the charge transport layer coating solution was changed to the following composition.
[Coating fluid for charge transport layer]
Polymer charge transport material of the following formula (14) 10 parts Silicone oil (KF-50: manufactured by Shin-Etsu Chemical Co., Ltd.) 0.001 part Tetrahydrofuran 100 parts

( Reference Example 20 )
Next, a surface protective layer coating solution having the following composition was applied to the photoconductor produced in Reference Example 1, and dried at 125 ° C. for 20 minutes to form a surface protective layer having an average film thickness of 2 μm. Produced.
[Surface protective layer coating solution]
3.8 parts of polycarbonate resin (Iupilon Z200: manufactured by Mitsubishi Gas Chemical Company)
Charge-transporting substance 2.8 parts of α- alumina fine particles 2.6 parts of formula (4) (specific ^{resistance: 2.5 × 10 12 Ω · cm} , average primary particle diameter: 0.5 [mu] m)
Cyclohexanone 80 parts Tetrahydrofuran 280 parts

( Reference Example 21 )
A photoconductor was prepared in the same manner as in Reference Example 20 , except that the surface protective layer coating solution used in Reference Example 20 was changed to the following.
[Surface protective layer coating solution]
3.8 parts of polycarbonate resin (Iupilon Z200: manufactured by Mitsubishi Gas Chemical Company)
Charge transport material of formula (4) 2.8 parts Silica fine powder 2.6 parts (specific resistance: 4 × 10 ¹³ Ω · cm, average primary particle size: 0.3 μm)
Cyclohexanone 80 parts Tetrahydrofuran 280 parts

( Reference Example 22 )
A photoconductor was prepared in the same manner as in Reference Example 20 , except that the surface protective layer coating solution used in Reference Example 20 was changed to the following.
[Surface protective layer coating solution]
3.8 parts of polycarbonate resin (Iupilon Z200: manufactured by Mitsubishi Gas Chemical Company)
2.8 parts of titanium oxide fine particles 2.6 parts (specific resistance: 1.5 × 10 ¹⁰ Ω · cm, average primary particle size: 0.5 μm)
Cyclohexanone 80 parts Tetrahydrofuran 280 parts

( Reference Example 23 )
A photoconductor was prepared in the same manner as in Reference Example 20 , except that the surface protective layer coating solution used in Reference Example 20 was changed to the following.
[Surface protective layer coating solution]
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: 10 ⁶ Ω · cm, average primary particle size 0.4 μm)
Cyclohexanone 80 parts Tetrahydrofuran 280 parts

(Example 24)
A photoconductor was prepared in the same manner as in Reference Example 20 , except that the surface protective layer coating solution used in Reference Example 20 was changed to the following.
[Surface protective layer coating solution]
6.6 parts α-alumina fine particles 2.6 parts of the following structural formula (15) (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.5 μm)
Cyclohexanone 120 parts Tetrahydrofuran 420 parts

(Example 1 )
A photoconductor was prepared in the same manner as in Reference Example 20 , except that the surface protective layer coating solution used in Reference Example 20 was changed to the following.
[Surface protective layer coating solution]
Low molecular charge transport material of the following structural formula (16) 2 parts Fluororesin particles (MPE-056, manufactured by Mitsui DuPont Fluorochemical Co., Ltd.) 11 parts Fluorosurfactant (Modiper F200, manufactured by NOF Corporation) 14 parts (solid content : 4.2 parts by weight)
Melamine resin 5 parts (Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals, Inc.)
Tetrahydrofuran 180 parts Cyclohexanone 50 parts

( Reference Example 25 )
An electrophotographic photosensitive member was produced in the same manner as in Reference Example 20 except that the drying temperature of the surface protective layer was changed to 110 ° C.

(Comparative Example 15)
An electrophotographic photosensitive member was produced in the same manner as in Reference Example 20 except that the drying temperature of the surface protective layer was changed to 140 ° C.

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. A 300,000 sheet passing test was conducted.
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 5.

It is sectional drawing which shows the structural example of the electrophotographic photoreceptor used for this invention. It is sectional drawing which shows another structural example of the electrophotographic photoreceptor used for this invention. It is sectional drawing which shows another structural example of the electrophotographic photoreceptor used for this invention. 1 is a schematic diagram for explaining an electrophotographic process and an electrophotographic image forming apparatus of the present invention. 1 is a schematic view of an electrophotographic image forming apparatus including a plurality of image forming elements of the present invention. It is a figure which shows the general example of the shape of a process cartridge. It is a figure which shows the result at the time of measuring an X-ray-diffraction spectrum about the titanyl phthalocyanine powder produced in the synthesis example 1. FIG.

Explanation of symbols

1C, 1M, 1Y, 1K Photoconductors 2C, 2M, 2Y, 2K Charging members 3C, 3M, 3Y, 3K Laser beams 4C, 4M, 4Y, 4K Developing members 5C, 5M, 5Y, 5K Cleaning members 6C, 6M, 6Y , 6K image forming element 7 transfer paper 8 paper feed roller 9 registration roller 10 transfer transport belt 11C, 11M, 11Y, 11K transfer brush 12 fixing device 31 conductive support 33 (first) intermediate layer 34 second intermediate layer 35 charge Generation layer 37 Charge transport layer 39 Protective layer 41 Photoconductor 42 Static elimination lamp 43 Charging roller 45 Image exposure unit 46 Development unit 47 Pre-transfer charger 48 Registration roller 49 Transfer paper 50 Transfer charger 51 Separation charger 52 Separation claw 53 Pre-cleaning charger 54 Far Brush 55 Cleaning brush and cleaning blade 56 La 57 transfer roller

Claims (3)

An electrophotographic photosensitive member in which an intermediate layer composed of at least an inorganic pigment and a thermosetting resin, a charge generation layer, a charge transport layer, and a surface protective layer are sequentially provided on a conductive support, and the intermediate layer coating solution Is applied on a conductive support, dried at a temperature of 110 to 140 ° C., and after applying a charge transport layer coating solution containing tetrahydrofuran as a solvent on the charge generation layer, a temperature not higher than the drying temperature of the intermediate layer. in dried, after application of the surface protective layer on the charge transport layer state, and are those obtained by drying at a drying temperature below the temperature of the intermediate layer, the binder resin of the surface protective layer contains a reactive hydroxyl group fluorocarbon surfactant and an electrophotographic photosensitive member, wherein the resin der Rukoto obtained by crosslinking reaction between the thermosetting resin monomer. 2. The electrophotographic photosensitive member according to claim 1, wherein the binder resin of the surface protective layer is a resin obtained by a crosslinking reaction between a fluorinated surfactant containing a reactive hydroxyl group and melamine. The binder resin of the surface protective layer is a resin obtained by a crosslinking reaction between a fluorosurfactant containing a reactive hydroxyl group, a charge transporting substance containing a reactive hydroxyl group, and a thermosetting resin monomer. The electrophotographic photoreceptor according to claim 1 , wherein the electrophotographic photoreceptor is characterized in that

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