JP2005189843A - Electrophotographic photoreceptor, image forming apparatus with the same, coating liquid for undercoat layer of the photoreceptor and method of preparing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high durability electrophotographic photoreceptor which considers environmental conservation from the viewpoint of air pollution and global warming and has superior electrostatic properties, and an electrophotographic image forming apparatus using the photoreceptor, and to provide a coating liquid for the photoreceptor having superior temporal stability of physical properties in production and capable of reducing energy consumption in a heat crosslinking step, and a method of preparing the photoreceptor. <P>SOLUTION: The electrophotographic photoreceptor includes an undercoat layer and a photosensitive layer on an electroconductive substrate, wherein the undercoat layer comprises at least a blocked isocyanate compound and a basic amine. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophotographic photosensitive member, and relates to an electrophotographic photosensitive member suitably used for a laser printer, a digital copying machine, and a laser facsimile, an electrophotographic image forming apparatus using the same, and coating for an undercoat layer of the electrophotographic photosensitive member. The present invention relates to a liquid and a manufacturing method using the same.

  The electrophotographic image forming apparatus has high speed and high printing quality, and is used in fields such as a copying machine and a laser beam printer. As a photoconductor used in an electrophotographic image forming apparatus, development of an organic photoconductor (OPC) using an organic photoconductive material has been promoted and has been gradually spread. In addition, the structure of the photoreceptor is also a function-separated photoreceptor structure in which a charge generation layer and a charge transport layer are separated from a single-layer photoreceptor in which a charge transfer complex structure or charge generation material is dispersed in a binder resin. The performance has also improved. In this function-separated type photoreceptor, at present, the mainstream is a structure in which an undercoat layer is first formed on an aluminum pipe, and then a charge generation layer and a charge transport layer are formed.

  The undercoat layer may be provided to improve the adhesion of the photosensitive layer, improve the coatability, improve the chargeability, prevent unnecessary charge injection from the support, and cover defects on the support. It is done. The subbing layer can be classified into a binder resin alone or a binder resin containing a pigment when classified roughly. Examples of the resin used for the undercoat layer include water-soluble resins such as polyvinyl alcohol and casein, alcohol-soluble resins such as copolymer nylon resins, polyurethane, melamine resins, phenol resins, alkyd resins, epoxy resins, and siloxane resins. Examples thereof include curable resins that form a three-dimensional network structure.

  Of these, water-soluble resins are inexpensive and have excellent characteristics, but they frequently dissolve in the solvent for the photosensitive layer coating solution during coating of the photosensitive layer, resulting in a significant deterioration in film formability. Nylon alcohol-soluble resins are highly water-absorbing and compatible, so they are highly environmentally dependent, and the characteristics of the photoreceptor change depending on humidity. In particular, since a large amount of moisture is absorbed into the undercoat layer at high humidity, a photoreceptor provided with an undercoat layer using an alcohol-soluble resin, particularly a nylon resin, is sensitive to repeated use at high temperature and high humidity or low temperature and low humidity. Body characteristics fluctuate greatly, causing abnormal images such as black spots and density reduction. Further, in order to increase the effect of concealing defects on the support and to enhance the scattering effect on incident light such as coherent light (for example, laser light) to suppress the generation of interference fringes, titanium oxide or the like is used for the undercoat layer. It is well known to disperse these inorganic pigments, but the tendency was not changed by mixing with such inorganic pigments.

Thermosetting resins that form a three-dimensional network structure with excellent solvent resistance and liquid stability have been used as binder resins. Among them, melamine resins, alkyd / melamine resin systems, and acrylic / melamine resin systems have been used. Resins such as phenolic resin, methoxymethylated nylon, etc. are said to be one of the causative substances of Housesick syndrome during resin production, and in order to use a large amount of formaldehyde that is currently listed as an air pollution target substance in the Air Pollution Control Law, Unreacted substances are occluded in these resins, and are generated in the thermal cross-linking treatment process after forming the undercoat layer. In order to prevent the release of generated formaldehyde into the atmosphere, it is necessary to install a recovery facility, which obviously costs money to introduce the facility.
From the above, there has been a demand for a thermally crosslinkable resin for an undercoat layer that does not generate formaldehyde during thermosetting and has little environmental dependency.

A typical example of the resin is a urethane resin.
Regarding the curing reaction of the urethane resin, the active hydrogen-containing group-containing compound such as an acrylic polyol is subjected to a hot-air drying treatment for a certain period of time in the presence of a curing agent such as a monomer containing an isocyanate group. A cured film is formed by initiating a three-dimensional network cross-linking reaction with the isocyanate group of the curing agent. However, the reactivity of the isocyanate group is very high. There is a problem that the time is short, and the coating liquid for electrophotographic photoreceptors, and also the isocyanate-based paints are stable in the presence of an alcohol solvent, an aqueous solvent, or an active hydrogen-containing group-containing compound and have a long pot life. With regard to isocyanates, application to the electrophotographic photoreceptor field is being studied.

For blocked isocyanate, the isocyanate group is protected with a blocking agent such as oxime, and by heating, an addition reaction with an active hydrogen-containing group-containing compound such as a hydroxyl group is started, and the blocking agent is removed and the crosslinking reaction proceeds. .
In this reaction, since the desorption temperature of the blocking agent by heating is high, the production of this electrophotographic photosensitive member requires more investment than the existing drying equipment, and the amount of energy used is large. Will also have an adverse effect on global warming.
That is, it has been desired to lower the desorption temperature of the blocking agent, that is, to reduce the crosslinking temperature, and to extend the usable time of the photoconductor coating solution to the limit.

  For example, a photoreceptor containing a blocked isocyanate in the intermediate layer and the undercoat layer of the electrophotographic photoreceptor is described (for example, see Patent Documents 1 to 5). Among these, tin compounds and basic compounds as catalysts are disclosed, but in this case, among the catalysts generally introduced in this way, not only the effect of reducing the heat treatment temperature of basic amine is great, but also Provided is an electrophotographic photosensitive member that is excellent in characteristics as an electrophotographic photosensitive member when contained in a pulling layer, has high in-machine potential stability in an image forming apparatus comprising the photosensitive member, and does not generate abnormal images. In addition, the present invention provides an undercoat layer coating solution for an electrophotographic photoreceptor excellent in liquid property stability, which is different from the present case.

JP 05-158267 A Japanese Patent Laid-Open No. 05-257312 Japanese Patent No. 0263557 Japanese Patent No. 026032828 Japanese Patent No. 025667090

  The object of the present invention is based on environmental protection from the viewpoint of air pollution and global warming, and provides an excellent electrostatic property, a highly durable electrophotographic photoreceptor, and an electrophotographic image forming apparatus using the photoreceptor, In production, the object is to provide a coating solution for a photoconductor and a method for producing the photoconductor, which have excellent stability over time of liquid properties and can reduce the amount of energy used in a thermal crosslinking step.

  The above-mentioned problem is characterized in that (1) “an electrophotographic photoreceptor comprising an undercoat layer and a photosensitive layer on a conductive support, wherein the undercoat layer contains at least a blocked isocyanate compound and a basic amine. (2) “In an electrophotographic photoreceptor comprising an undercoat layer and a photosensitive layer on a conductive support, the undercoat layer contains at least a blocked isocyanate compound and a basic amine. (3) “Electrophotographic photoreceptor comprising an undercoat layer and a photosensitive layer on a conductive support, wherein the undercoat layer comprises at least a blocked isocyanate compound and a basic amine. An undercoat layer coating solution for an electrophotographic photosensitive member, ”(4)“ in an electrophotographic photosensitive member comprising an undercoat layer and a photosensitive layer on a conductive support, Electrophotographic image forming apparatus comprising an electrophotographic photosensitive member characterized in that the drawing layer contains at least a blocked isocyanate compound and a basic amine ”, (5)“ Undercoat layer on the conductive support, photosensitive An electrophotographic photosensitive member comprising a layer, wherein the undercoat layer contains an oil-free alkyd resin containing at least a blocked isocyanate compound and a basic amine, and containing a hydroxyl group as a main component. (6) “An oil having an undercoat layer and a photosensitive layer on a conductive support, wherein the undercoat layer contains at least a blocked isocyanate compound and a basic amine, and contains a hydroxyl group as a main component. A method for producing an electrophotographic photosensitive member characterized by containing a free alkyd resin ”, (7)“ on a conductive support ” An electrophotographic photosensitive member comprising an undercoat layer and a photosensitive layer, wherein the undercoat layer contains at least a blocked isocyanate compound and a basic amine, and contains an oil-free alkyd resin containing a hydroxyl group as a main agent. “Undercoat layer coating solution for electrophotographic photoreceptor”, (8) “An electrophotographic photoreceptor comprising an undercoat layer and a photosensitive layer on a conductive support, wherein the undercoat layer comprises at least a blocked isocyanate compound and a basic amine. And an electrophotographic photosensitive member containing an oil-free alkyd resin containing a hydroxyl group as a main component, ”(9)“ Content of basic amine ” Is 0.0001 to 5% based on the total of the oil-free alkyd resin and the blocked isocyanate. (10) “The basic amine content is 0.0001 to 5% with respect to the total of the oil-free alkyd resin and the blocked isocyanate”. The method for producing an electrophotographic photoreceptor according to item 6) ”, (11)“ the content of the basic amine is 0.0001 to 5% with respect to the total of the oil-free alkyd resin and the blocked isocyanate ”. The undercoat layer coating solution for an electrophotographic photosensitive member according to item (7) above, (12) "The content of the basic amine is 0. 0 with respect to the sum of the oil-free alkyd resin and the blocked isocyanate." The electrophotographic image forming apparatus according to item (8), comprising an electrophotographic photosensitive member of 0001 to 5%, and (13) the photosensitive material according to item (1). Body and belt Means, developing means, and supporting at least one means selected from the cleaning means integrally, is solved by the process cartridge ", which is a detachably attached to the image forming apparatus main body.

  According to the present invention, an electrophotographic photosensitive member and an electrophotographic image forming apparatus having the same are obtained without generating formaldehyde as an environmental pollutant and preventing deterioration of charging and sensitivity, and the equipment investment cost is reduced and heat is reduced. It is possible to provide a coating solution for an undercoat layer of an electrophotographic photoreceptor that can reduce the amount of energy used for the crosslinking treatment, and a method for producing an electrophotographic photoreceptor using the same.

The electrophotographic photoreceptor of the present invention will be described below.
FIG. 1 is a sectional view showing one example of the constitution of the electrophotographic photosensitive member of the present invention, in which at least an undercoat layer (33) and a photosensitive layer (34) are laminated on a conductive support (32). Have taken.
FIG. 2 is a cross-sectional view showing another structural example of the present invention, in which an undercoat layer (33), a charge generation layer (35), and a charge transport layer (36) are laminated on a conductive support (32). It has a configuration.

The undercoat layer (33) contains at least a blocked isocyanate. In the production of electrophotographic photoreceptors, liquid storage stability is important when resin and pigment are dispersed in a solvent as raw materials. Therefore, it is preferable to use, as a cross-linking material, a blocked isocyanate with a blocking agent or an internally blocked blocked isocyanate so as not to cause a problem even when stored for a long time under high temperature and high humidity such as summer.
Examples of these blocked isocyanate resins include isophorone diisocyanate using ε-caprolactam as a blocking agent, trade names of HULS, Inc .: IPDI-B1065, IPDI-B1530, or internally blocked uretdione-linked block isophorone. The product name: IPDI-BF1540 by the Hills (HULS) company which is diisocyanate is mentioned. Moreover, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane-4,4′-diisocyanate, hexamethylene diisocyanate and the like blocked with oxime can be mentioned.
Examples of oximes include formaldehyde oxime, acetaldoxime, methyl ethyl ketoxime, and cyclohexanone oxime.
Examples of blocked isocyanates blocked with oxime include trade names DM-60 and DM-160 manufactured by Meisei Chemical Industry Co., Ltd., Bernock B7-887-60, B3-867, and DB980K manufactured by Dainippon Ink, Inc.

The undercoat layer (33) contains a basic amine.
Basic amines mainly include aliphatic amines, aromatic amines, and alicyclic amines. Examples of aliphatic amines include ammonia, monoethanolamine, diethanolamine, triethanolamine, polymethylenediamine (ethylenediamine, diaminobutane, diamino). Propane, hexane diamine, dodecane diamine, etc.), polyethylene polyamine (diethylene triamine, triethylene tetramine, etc.), polyether diamine and the like.
Examples of the aromatic amine include 2,4- or 2,6-diaminotoluene (TDA), crude TDA, 1,2-, 1,3- or 1,4-phenylenediamine, diethyltolylenediamine, 4, 4'-diaminodiphenylmethane (MDA), crude MDA, 1,5-naphthylenediamine, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylcyclohexane Etc.

Examples of the basic amine having an aromatic ring include 1,2-, 1,3- or 1,4-xylenediamine.
Examples of the alicyclic amine include 4,4′-diaminodicyclohexylmethane, 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 3-amino-1-cyclohexylaminopropane, and bis (aminomethyl) cyclohexane. , Isophoronediamine, norbornanediamine, mensendiamine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraoxaspiro (-5,5-) undecane and the like.

  In addition, N, N, N, N-tetramethylhexamethylenediamine, N, N, N, N-tetramethylpropylenediamine, N, N, N, N, N-pentamethyldiethylenetriamine, N, N, N , N-tetramethylethylenediamine, N-methyl-N′-dimethylaminoethylpiperazine, N, N-dimethylaminocyclohexylamine, bis (dimethylaminoethyl) ether, tris (N, N-dimethylaminopropyl) hexahydro-S— Triazine, methylmorpholine, ethylmorpholine, triethylenediamine, 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, and the like may be used.

These amine compounds have at least one of —NH ₂ group and —NH— group and have an average molecular weight of 110 or more, preferably 120 to 5000, more preferably 120 to 1000, and still more preferably 120 to 500. The compounding amount of the amine compound is 0.0001 to 5%, preferably 0.001 to 1% of the amine compound with respect to the total amount of the main agent (a) and the curing agent (b). It is important to select such that NH ₂ groups and / or —NH— groups may be present. When the proportion is less than 0.0001%, the crosslinking temperature, that is, the desorption temperature of the blocking agent hardly changes. Therefore, in terms of electrical characteristics of the photoreceptor, by reducing the crosslinking temperature, a large amount of unreacted crosslinking material or main resin exists, so that the residual potential is high from the beginning or the photosensitivity is reduced. It causes a decrease in image density, and becomes noticeable due to deterioration due to electrostatic fatigue during continuous use. On the other hand, if it exceeds 5%, mixing failure occurs when the two-liquid mixture is used, and the pot life of the liquid decreases. In addition, the presence of an excessive basic substance excessively prevents charge injection during charge separation after charge generation by light irradiation, so that a residual potential increase due to electrostatic fatigue becomes significant. These basic amine compounds can be used alone or as a mixture of two or more in combination with a tertiary amino alcohol.

As the main resin contained in the undercoat layer, a resin having active hydrogen can be selected.
Polyether polyols, polyester polyols, acrylic polyols, epoxy polyols, oil-free alkyd resins, epoxy resins and the like generally called polyols can be mentioned, and oil-free alkyd resins containing at least hydroxyl groups are particularly excellent.

Oil-free alkyd resin is a saturated polyester resin consisting of a polybasic acid and a polyhydric alcohol, and has a characteristic of having a straight chain structure linked by an ester bond that does not contain fatty acids. Furthermore, there are many types depending on the modifier.
Preferable specific examples of the oil-free alkyd resin containing a hydroxyl group include Beckolite M-6401-50, M-6402-50, M-6603-60, M-6605-60, 46-118, 46-119, 52-584, M-6154-50, M-6301-45, 55-530, 54-707, 46-169-S, M-6201-40-1M, M-6205-50, 54-409 Ink Chemical Industries, Ltd .: trade name of oil-free alkyd resin), Espel 103, 110, 124, 135 (trade name of oil-free alkyd resin, manufactured by Hitachi Chemical Co., Ltd.) and the like.

  The hydroxyl value of the oil-free alkyd resin is preferably 60 or more. When the hydroxyl value is less than 60, there are few reactive sites with isocyanate, so that sufficient crosslinking is not performed, film formability is deteriorated, and adhesion between the photosensitive layer and the conductive support is deteriorated. On the other hand, if the hydroxyl value is greater than 150, the moisture resistance is poor when unreacted functional groups remain, and charge tends to be accumulated as a photoconductor in a humid environment. This is not preferable because the density of the dark part and the gradation are lowered due to the increase of the dark part potential. The term “hydroxyl value” as used herein refers to a value measured by the method defined in JIS K0070.

  The mixing ratio between the oil-free alkyd resin containing a hydroxyl group contained in the undercoat layer (33) and the blocked isocyanate resin is such that the number of moles of hydroxyl groups present in the resin is equal to the number of moles of isocyanate groups in the blocked isocyanate resin. Is desirable. If either the hydroxyl group or isocyanate group of the reactive group that cross-links both exists in excess and remains as an unreacted component, the photoreceptor preferably accumulates charges on the unreacted group component in the undercoat layer. Absent

The undercoat layer (33) may contain a metal oxide as a white pigment.
Examples of metal oxides include titanium oxide, zinc oxide, lead white, aluminum oxide, aluminum oxide, silicon oxide, indium oxide, zirconium oxide, and magnesium oxide. Among these, use of aluminum oxide, zirconium oxide, and titanium oxide is desirable. . Titanium oxide hardly absorbs visible light and near-infrared light and is white, and is desirable for increasing the sensitivity of the photoreceptor. Further, since the refractive index is relatively large, moire generated when an image is written with coherent light such as laser light can be effectively prevented.
Moreover, the purity of the titanium oxide that can be used in the present invention is required to be 99.4% or more. Impurities contained in the titanium oxide are mainly hygroscopic substances such as Na ₂ O and K ₂ O and ionic substances. When the purity of the titanium oxide is lower than 99.4%, the characteristics of the photoreceptor are the environment. (Especially humidity) and repeated use may cause large fluctuations. Further, these impurities are liable to cause image defects such as black spots. The purity of titanium oxide in the undercoat layer shown in the present invention can be determined by the measurement method shown in JIS K5116.

  Furthermore, the ratio P / R of titanium oxide (P) and binder resin (main resin + blocked isocyanate as a crosslinking agent) (R) contained in the undercoat layer of the present invention is 0.9 / 1 to 1 in volume ratio. A range of 2.5 / 1 is preferred. When the P / R ratio of the undercoat layer is less than 0.9 / 1, the properties of the undercoat layer depend on the properties of the binder resin, and the characteristics of the photoreceptor greatly change particularly with changes in temperature and humidity and repeated use. End up. When the P / R ratio exceeds 2/1, voids increase in the layer of the undercoat layer, the adhesion to the charge generation layer decreases, and when it further exceeds 3/1, air accumulates, When the photosensitive layer is applied and dried, it causes bubbles and causes application defects.

  Solvents used in the undercoat layer (33) include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin and the like. Is mentioned.

  The inorganic pigment contained in the undercoat layer (33) has a particle size of 0.05 to 1 μm, preferably 0.1 to 0.5 μm. In the present invention, the thickness of the undercoat layer is preferably set in the range of 0.1 to 50 μm, more preferably in the range of 2 to 8 μm. If the thickness of the undercoat layer is less than 2 μm, the function as the undercoat layer is insufficient and the effect on pre-exposure fatigue is reduced. On the other hand, if the thickness of the undercoat layer exceeds 8 μm, the smoothness of the coating surface is lost, the sensitivity of the photoreceptor is lowered, and even if the effect on pre-exposure fatigue is preserved, the effect on environmental fluctuations is lost. .

Next, the conductive support and the photosensitive layer will be described.
Examples of the conductive support (32) 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, 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 After forming the tube, a tube subjected to surface treatment such as cutting, superfinishing or polishing can be used. Further, an endless nickel belt and an endless stainless steel belt disclosed in JP-A-52-36016 can also be used as the conductive support (32).

  In addition to this, the conductive support dispersed in a suitable binder resin and coated with the conductive powder on the support can be used as the conductive support (32) of the present invention. Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, and silver, or metal oxide such as conductive titanium oxide, conductive tin oxide, and ITO. Examples include powder. The binder resin used at the same time is polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, 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, Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as melamine resin, urethane resin, phenol resin, and alkyd resin. Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, 2-butanone, toluene and the like.

  Furthermore, it is electrically conductive by a heat-shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon (registered trademark) on a suitable cylindrical substrate. Those provided with a conductive layer can also be used favorably as the conductive support (32) of the present invention.

As the binder resin used for the charge generation layer (35), the butyral resin shown in the present invention is used as the main component (50 wt% or more), but polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin are used. , Polyvinyl formal, polyvinyl ketone, polystyrene, poly-vinyl carbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyamide, polyvinyl pyridine, cellulosic resin, casein, Polyvinyl alcohol, polyvinyl pyrrolidone, etc. may be used together if necessary.
The amount of the binder resin is 10 to 500 parts by weight, preferably 25 to 300 parts by weight, based on 100 parts by weight of the charge generating material.

Examples of the solvent used here include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin and the like. The charge generation layer (35) is formed by dispersing these components in a suitable solvent using a ball mill, attritor, sand mill, ultrasonic wave, etc., applying this to the undercoat layer (33), and drying. The
The film thickness of the charge generation layer is 0.01 to 5 μm, preferably 0.1 to 2 μm.

  The charge transport layer (36) can be formed by dissolving or dispersing a charge transport material and a binder resin in a suitable solvent, and applying and drying the solution on the charge generation layer. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed. Examples of the solvent used here include chloroborum, tetrahydrofuran, dioxane, toluene, monochlorobenzene, dichloroethane, dichloromethane, cyclohexanone, methyl ethyl ketone, and acetone.

The charge transport material contained in the charge transport layer (36) includes a hole transport material and an electron transport material.
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, bisstilbene derivatives, enamine derivatives, Other known materials such as other polymerized hole transport materials may be mentioned.

  Examples of the binder resin used for the charge transport layer include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. Coalescence, polyvinyl acetate, polyvinylidene chloride, polyarylate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, Thermoplastic or thermosetting resins such as melamine resin, urethane resin, phenol resin, alkyd resin, and various polycarbonate copolymers described in JP-A-5-158250 and JP-A-6-51544. It is.

  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 50 μm. As the solvent used here, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used.

  In the present invention, a leveling agent and an antioxidant may be added to the charge transport layer (36). As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain can be used, and the amount used is 0 with respect to 100 parts by weight of the binder resin. ˜1 part by weight is suitable. Antioxidants such as hindered phenol compounds, sulfur compounds, phosphorus compounds, hindered amine compounds, pyridine derivatives, piperidine derivatives, morpholine derivatives can be used as the antioxidant, and the amount used is 100 weight of binder resin. About 0 to 5 parts by weight per part is appropriate.

  As the coating method of the electrophotographic photoreceptor of the present invention, methods such as dip coating, spray coating, bead coating, nozzle coating, spinner coating, ring coating, Mayer bar coating, roller coating, curtain coating, etc. can be used.

  The electrophotographic image forming apparatus having the electrophotographic photosensitive member of the present invention will be described. As shown in FIG. 3, a charging member (12) is formed on the outer peripheral surface of a drum-shaped electrophotographic photosensitive member (12) rotating in the direction of arrow A. By 1), the photoreceptor (12) is charged to a predetermined positive or negative voltage. A positive or negative DC voltage is applied to the charging member (1). The DC voltage applied to the charging member (1) is preferably −2000V to + 2000V.

The charging member (1) may be applied with a pulsating voltage by superimposing an AC voltage in addition to the DC voltage. The AC voltage superimposed on the DC voltage is preferably a peak-to-peak voltage of 4000 V or less. However, when an AC voltage is superimposed, the charging member and the electrophotographic photosensitive member may vibrate and generate abnormal noise. A desired voltage may be applied instantaneously to the charging member (1), but the applied voltage may be gradually increased to protect the photoreceptor.
In addition to a charging method in which a charging member is indirectly arranged, a so-called scorotron method and a corotron method, a charging method directly arranged on a photoconductor that can suppress the generation of acid gas has been proposed.

  The charging member (1) may be rotated in the same direction as that of the photosensitive member (12), or may be slid on the outer peripheral surface of the photosensitive member without being rotated. Further, the charging member may have a function of cleaning residual toner on the photoconductor (12). In this case, there is no need to provide the cleaning means (10).

  The charged photoreceptor (12) is then subjected to optical image exposure (6) (such as slit exposure or laser beam scanning exposure) by an image exposure means (not shown). During this exposure scan, exposure is interrupted for the non-image area of the current surface, and reversal development is performed by applying a development bias slightly lower than the surface potential to the image area that has become low potential by exposure, thereby An electrostatic latent image corresponding to the original image including the non-image portion described above is sequentially formed.

  The electrostatic latent image is then developed with toner by the developing means (7), and the toner developed image is transferred from the sheet feeding unit (not shown) to the photosensitive member (12) and the transfer member (8) by the transfer charging means (8). In the meantime, the image is sequentially transferred onto the surface of the recording material (9) fed in synchronism with the rotation of the photosensitive member (12). The recording material (9) that has received the image transfer is separated from the surface of the photosensitive member, introduced into an image fixing means (not shown), subjected to image fixing, and printed out as a copy (copy).

  The surface of the photoconductor (12) after the image transfer is made normal by the removal of the transfer residual toner by the cleaning means (10), is subjected to charge removal processing by the pre-exposure (11), and is repeatedly used for image formation. The

The electrophotographic image forming apparatus is a process in which a plurality of components such as the above-described photoreceptor and developing means are integrally coupled as an apparatus unit, and this unit is configured to be detachable from the apparatus main body. A cartridge may be used.
A process cartridge is characterized in that the above-described photosensitive member and at least one means selected from a charging means, a developing means, and a cleaning means are integrally supported and are detachable from the image forming apparatus main body.
For example, as shown in FIG. 4, at least the photosensitive member (12), the charging member (1), and the developing means (7) are accommodated in a container (20) to form one process cartridge, and this process cartridge is a rail of the apparatus main body. It is possible to use a guide means that can be detachably attached. The cleaning means (10) may or may not be provided in the container (20).

  Further, as shown in FIG. 5, at least the photosensitive member (12) and the charging member (1) are accommodated in the first container (21) to form the first electrophotographic unit, and at least the developing means (7) is the second electrophotographic unit. A second electrophotographic unit may be stored in the container (22), and the first apparatus unit and the second apparatus unit may be detachable. The cleaning means (10) may or may not be provided in the container (21).

  4 and 5, a transfer member (23) is used as the transfer charging means. As the transfer member (23), the same configuration as that of the charging member (1) can be used. It is desirable to apply a DC voltage of 400V to 2000V to the transfer member (23) used as the transfer charging means, and (24) is a fixing means.

Hereinafter, the present invention will be described with reference to examples.
Example 1
(Preparation of coating liquid for undercoat layer and its coating method)
80 parts of titanium oxide (CREL, manufactured by Ishihara Sangyo), oil-free alkyd resin (Beckolite M6163-60 (solid content 60 wt%): manufactured by Dainippon Ink & Chemicals), block isocyanate resin (Bernock B3-867 (solid) 70 wt%): manufactured by Dainippon Ink Chemical Co., Ltd.) A mixture of 20 parts by weight, 100 parts by weight of methyl ethyl ketone and 0.23 parts by weight of diethylamine was dispersed with a ball mill for 72 hours to prepare an undercoat layer coating solution. Three drums are coated on an aluminum drum having a diameter of 30 mm and a length of 340 mm using a glass, dried at 110 ° C. for 20 minutes, 130 ° C. for 20 minutes, and 150 ° C. for 20 minutes, and coated with a 4 μm thick undercoat layer. Produced.

(Preparation of coating solution for charge generation layer and its coating method)
12 parts by weight of τ-type metal-free phthalocyanine (TPA-891: manufactured by Toyo Ink Co., Ltd.) and 24 parts by weight of the disazo pigment of the following structural formula (1) were dispersed in 330 parts by weight of cyclohexanone with a ball mill for 216 hours. After the completion of dispersion, a resin solution prepared by dissolving 6 parts by weight of polyvinyl butyral (XYHL: manufactured by UCC) in 850 parts by weight of methyl ethyl ketone and 1100 parts by weight of cyclohexanone was added and dispersed for 3 hours to prepare a coating solution for a charge generation layer. . This was applied to an undercoat drum prepared under three kinds of drying conditions and dried at 130 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.

(Preparation of coating solution for charge transport layer and its coating method)
8 parts by weight of a charge transport material represented by the following structural formula (2), 10 parts by weight of polycarbonate (Z type: viscosity average molecular weight 50,000), 0.002 parts by weight of silicone oil (KF-50: manufactured by Shin-Etsu Chemical Co., Ltd.) It melt | dissolved in 100 weight part of tetrahydrofuran, and created the coating liquid for charge transport layers. This was applied onto the charge generation layer and dried at 130 ° C. for 20 minutes to form a charge transport layer having a thickness of 30 μm. Thus, a photoreceptor of Example 1 was obtained.

Example 2
The same as Example 1 except that the amount of diethylamine added to the coating solution for the undercoat layer of Example 1 was changed to 0.0023 parts by weight.

Example 3
The same as Example 1 except that the amount of diethylamine added to the coating liquid for the undercoat layer of Example 1 was changed to 1.15 parts by weight.

Example 4
The same as Example 1 except that the amount of diethylamine added to the coating solution for the undercoat layer of Example 1 was changed to 1.73 parts by weight.

Example 5
The same as Example 1 except that it was changed to triethylamine instead of diethylamine added to the coating liquid for the undercoat layer of Example 1.

Example 6
Example 2 is the same as Example 2 except that triethylamine is used instead of diethylamine added to the undercoat layer coating solution of Example 2.

Example 7
Example 3 is the same as Example 3 except that triethylamine is used instead of diethylamine added to the coating solution for the undercoat layer of Example 3.

Example 8
Example 4 The same as Example 3 except that the solution was changed to triethylamine instead of diethylamine added to the undercoat layer coating solution.

Examples 9-12
It is the same as that of Examples 1-4 except having changed into the ethylamine amine instead of the diethylamine added to the coating liquid for undercoat layers of Examples 1-4.

Examples 13-16
Examples 1-4 are the same as Examples 1-4 except that diethylethanolamine is used instead of diethylamine added to the undercoat layer coating solution.

Example 17
The undercoat layer coating solution of Example 1 was changed as follows.
(Preparation of coating liquid for undercoat layer and its coating method)
80 parts of titanium oxide (CREL Ishihara Sangyo, purity 99.7 wt%), oil-free alkyd resin (M6401-50) (solid content 50 wt%, hydroxyl value 130: manufactured by Dainippon Ink and Chemicals) 25 parts by weight, blocked isocyanate resin ( Bernock B7-887-50 (solid content: 60 wt%): Dainippon Ink Chemical Co., Ltd.) 12.5 parts by weight, diethylethanolamine 0.0002 parts by weight, and a mixture of methyl ethyl ketone 100 parts by weight were dispersed in a ball mill for 72 hours. Prepared as a coating solution for the undercoat layer, using this, three coated on an aluminum drum with a diameter of 30 mm and a length of 340 mm, dried at 110 ° C. for 20 minutes, 130 ° C. for 20 minutes, 150 ° C. for 20 minutes, A drum coated with an undercoat layer having a thickness of 4 μm was prepared.

Example 18
The same as Example 17 except that the amount of diethylethanolamine added to the coating solution for the undercoat layer of Example 17 was changed to 0.2 parts by weight.

Example 19
The same as Example 17 except that the amount of diethylethanolamine added to the coating solution for the undercoat layer of Example 17 was changed to 0.2 parts by weight.

Example 20
The same as Example 17 except that the amount of diethylethanolamine added to the coating solution for the undercoat layer of Example 17 was changed to 1 part by weight.

Example 21
Example 17 The same as Example 17 except that diethylethanolamine added to the undercoat layer coating solution was changed to hexamethylenediamine.

Example 22
Example 18 Same as Example 18 except that the solution was changed to hexamethylenediamine instead of diethylethanolamine added to the undercoat layer coating solution.

Example 23
Example 19 Same as Example 19 except that the solution was changed to hexamethylenediamine instead of diethylethanolamine added to the undercoat layer coating solution.

Example 24
Example 20 The same as Example 20, except that diethylethanolamine added to the undercoat layer coating solution was changed to hexamethylenediamine.

Example 25
Example 17 The same as Example 17 except that methylethanolamine was used instead of diethylethanolamine added to the coating solution for the undercoat layer of Example 17.

Example 26
Example 18 Same as Example 18 except that methylethanolamine was used instead of diethylethanolamine added to the undercoat layer coating solution.

Example 27
Example 19 Same as Example 19 except that methylethanolamine was used instead of diethylethanolamine added to the undercoat layer coating solution.

Example 28
Example 20 Same as Example 20 except that methylethanolamine was used instead of diethylethanolamine added to the undercoat layer coating solution.

Examples 29-42
Similarly, using the compounds shown in Table 1, the photoreceptors of Examples 29 to 42 were obtained under the conditions shown in Table 1.

Comparative Example 1
The same as Example 1 except that the addition of diethylamine in the undercoat layer coating solution of Example 1 was eliminated.

Comparative Example 2
The same as Example 1 except that 0.23 parts by weight of dibutyltin laurate was added in place of the diethylamine of Example 1.

Comparative Example 3
The same as Example 17 except that the addition of diethylethanolamine in the coating liquid for the undercoat layer of Example 17 was eliminated.

Comparative Example 4
Example 17 is the same as Example 17 except that 0.0002 part by weight of octyltin is added in place of diethylethanolamine in the undercoat layer coating solution.

  For each of the three electrophotographic photosensitive drums produced in Examples 1-42 and Comparative Examples 1-4 obtained as described above, they were installed in the Ricoh Co., Ltd. Imagio MF2730, and the charging bias for the charging roller was set at that time. Evaluation was made by measuring white part potential (Vw) and black part potential (VL) when set to -1650V. After that, the endurance test was continuously performed on 30,000 sheets with 5% black solid chart paper, the paper passing test was performed, the white part potential (Vw) black part potential (VL) was measured before and after the paper passing test, and the image was evaluated. It was. As the image evaluation, the black portion image density was visually evaluated based on the presence or absence of an abnormal image in a 5% chart, a blank paper image, and a 16 gradation image and the 16 gradation image. Further, the viscosity of the undercoat layer coating solution was measured with an E-type viscometer (type: ELD manufactured by Tokyo Keiki Co., Ltd.) at 20 ° C.

  Table 1 shows the results of evaluating the changes in the physical properties of Examples 1-42 and Comparative Examples 1-4 at normal temperature and humidity in the initial and actual machine potentials after 30,000-sheet passing test, presence of abnormal images, and liquid physical properties. ing.

According to this result, in Examples 1 to 42 to which a basic amine is added, the thermal cross-linking temperature is 130 ° C. lower than the usual 150 ° C. compared to Comparative Examples 1 and 2, and the actual internal potential is 110 ° C. No increase in VL or decrease in black portion density occurs. From this result, it is shown that the crosslinking treatment at a low temperature is possible as compared with the current situation. If the amount of basic amine added is 0.0001 to 5%, there is no particular problem. On the other hand, if the amount added is 0.0001% or less, the thermal crosslinking temperature is lowered. It can be seen that a decrease in VL and image density are caused, and at 5% or more, an increase in VL over time, which seems to be due to the presence of excess basic amine, is caused.
It can be seen that the physical properties of the coating liquid for the undercoat layer are also caused by an increase in viscosity which is considered to be due to the presence of excessive basic amine, and the addition amount is particularly excellent at 0.0001 to 5%.
In addition, the tin compound in the comparative example is inferior because local black spots occur in the trim image as the number of sheets passed passes.

It is sectional drawing which shows an example of the laminated constitution of the electrophotographic photoreceptor of this invention. It is sectional drawing which shows the other example of a layer structure of the electrophotographic photoreceptor of this invention. It is a front view which shows an example of the electrophotographic image forming apparatus of this invention. It is a front view which shows the other example of the electrophotographic image forming apparatus of this invention. It is a front view which shows the other example of the electrophotographic image forming apparatus of this invention.

Explanation of symbols

1: Charging member 6: Exposure means 7: Development means 8: Transfer member (corona method)
9: Recording material 10: Cleaning means 11: Auxiliary power means 12: Photoconductor 20: Container 21: Container 22: Container 23: Transfer member 24: Fixing means 32: Conductive support 33: Undercoat layer 34: Photosensitive layer 35 : Charge generation layer 36: Charge transport layer

Claims (13)

An electrophotographic photoreceptor comprising an undercoat layer and a photosensitive layer on a conductive support, wherein the undercoat layer contains at least a blocked isocyanate compound and a basic amine. An electrophotographic photoreceptor comprising an undercoat layer and a photosensitive layer on a conductive support, wherein the undercoat layer contains at least a blocked isocyanate compound and a basic amine. An electrophotographic photoreceptor comprising an undercoat layer and a photosensitive layer on a conductive support, wherein the undercoat layer contains at least a blocked isocyanate compound and a basic amine. Engineering liquid. An electrophotographic photoreceptor comprising an undercoat layer and a photosensitive layer on a conductive support, wherein the undercoat layer comprises an electrophotographic photoreceptor comprising at least a blocked isocyanate compound and a basic amine. Electrophotographic image forming apparatus. In an electrophotographic photoreceptor comprising an undercoat layer and a photosensitive layer on a conductive support, the undercoat layer contains at least a blocked isocyanate compound and a basic amine, and contains an oil-free alkyd resin containing a hydroxyl group as a main component. An electrophotographic photosensitive member characterized by comprising: In an electrophotographic photoreceptor comprising an undercoat layer and a photosensitive layer on a conductive support, the undercoat layer contains at least a blocked isocyanate compound and a basic amine, and contains an oil-free alkyd resin containing a hydroxyl group as a main component. And a method for producing an electrophotographic photosensitive member. In an electrophotographic photoreceptor comprising an undercoat layer and a photosensitive layer on a conductive support, the undercoat layer contains at least a blocked isocyanate compound and a basic amine, and contains an oil-free alkyd resin containing a hydroxyl group as a main component. An undercoat layer coating solution for an electrophotographic photosensitive member. In an electrophotographic photoreceptor comprising an undercoat layer and a photosensitive layer on a conductive support, the undercoat layer contains at least a blocked isocyanate compound and a basic amine, and contains an oil-free alkyd resin containing a hydroxyl group as a main component. An electrophotographic image forming apparatus comprising the electrophotographic photosensitive member. 6. The electrophotographic photoreceptor according to claim 5, wherein the content of the basic amine is 0.0001 to 5% with respect to the total of the oil-free alkyd resin and the blocked isocyanate. The method for producing an electrophotographic photoreceptor according to claim 6, wherein the content of the basic amine is 0.0001 to 5% with respect to the total of the oil-free alkyd resin and the blocked isocyanate. The undercoat layer coating solution for an electrophotographic photosensitive member according to claim 7, wherein the content of the basic amine is 0.0001 to 5% based on the total of the oil-free alkyd resin and the blocked isocyanate. . The electrophotographic photosensitive member according to claim 8, comprising an electrophotographic photosensitive member having a content of the basic amine of 0.0001 to 5% with respect to the total of the oil-free alkyd resin and the blocked isocyanate. Image forming apparatus. 2. A process cartridge comprising: a photosensitive member according to claim 1; and at least one unit selected from a charging unit, a developing unit, and a cleaning unit.

Images