JPS6335973B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composite electrophotographic plate that is effective for creating images by electrophotography, and more particularly to a composite electrophotographic plate having a charge transport layer with excellent durability (wear resistance). Conventionally, binder resins for charge transport layers in composite electrophotographic plates include polyethylene, polystyrene, polybutadiene, styrene-butadiene copolymers, polymers and copolymers of acrylic esters or methacrylic esters, polyesters, and polyamides. , polycarbonates, epoxy resins, urethane resins, silicone resins, alkyd resins, cellulose resins, vinyl polymers and copolymers such as polyvinyl chloride and polyvinyl acetate, etc. In order to increase the properties, mixtures of the above resins and plasticizers have also been proposed. When these resins are used as binder resins for charge transport layers, they all have good electrophotographic properties, but they have the disadvantage of inferior durability compared to inorganic photoreceptors, such as selenium photoreceptors. and
This was a major hindrance to commercialization. Particularly in recent years, laser beam printers that use lasers as light sources have been developed as computer terminal equipment printers.
In this case, it is necessary to have more durability than conventional electrophotographic plates for general-purpose copying machines. An object of the present invention is to overcome the drawbacks of the conventional composite electrophotographic plates described above and to provide a composite electrophotographic plate with extremely excellent durability. To summarize the present invention, the composite electrophotographic plate of the present invention is a composite electrophotographic plate in which a charge generation layer and a charge transport layer are laminated on a conductive support. Agent resin has general formula [In the formula, R ₁ represents a hydrogen atom or a methyl group,
X ₁ is -COOR ₂ (However, R ₂ is a hydrogen atom, carbon number 4
At least one monomer selected from the group consisting of the following alkyl group or 2-ethylhexyl group) and the general formula [In the formula, R ₃ represents a hydrogen atom or a methyl group,
X ₂ is

[Formula] (where R ₄ represents a hydrogen atom or an alkyl group having 4 or less carbon atoms),

[Formula] (where R ₅ represents a hydrogen atom or a methyl group) or

It is made of a thermosetting acrylic polymer containing at least one monomer selected from the group consisting of monomers represented by general formula [In the formula, Y is

【formula】

【formula】

[Formula] and

[Formula] represents at least one heterocyclic group selected from the group consisting of (however, Z represents O or S, and the heterocyclic group may be substituted); and R ₉ and R ₁₀ represent an alkyl group having 3 or less carbon atoms. In general, factors that determine the lifespan of electrophotographic plates include, in addition to deterioration of the photoconductive material itself, the occurrence of scratches due to friction with external paper (transfer paper) or developer. In particular, since organic electrophotographic plates are softer than inorganic electrophotographic plates, they are more susceptible to scratches and require improved wear resistance (durability). As a result of various studies on improving this abrasion resistance, the present inventors have discovered that in a composite electrophotographic plate composed of a charge generation layer and a charge transport layer, The present invention was developed based on the discovery that the following resins are suitable as a binder resin for a charge transport layer containing a compound represented by the general formula () as a charge transport substance, and that the cured product thereof has excellent wear resistance. I was able to complete it. The binder resin in the present invention has the general formula [In the formula, R ₁ represents a hydrogen atom or a methyl group,
X ₁ is -COOR ₂ (However, R ₂ is a hydrogen atom, carbon number 4
At least one monomer selected from the group consisting of the following alkyl group or 2-ethylhexyl group) and the general formula [In the formula, R ₃ represents a hydrogen atom or a methyl group,
X ₂ is

[Formula] (where R ₄ represents a hydrogen atom or an alkyl group having 4 or less carbon atoms),

[Formula] (where R ₅ represents a hydrogen atom or a methyl group) or

A thermosetting acrylic polymer containing as its constituent monomer unit at least one member selected from the group consisting of monomers represented by the following formula can be used. Specific examples of the monomer unit represented by the above general formula () include acrylic acid, ethyl acrylate,
2-ethylhexyl acrylate, methacrylic acid,
Examples include methyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate. Further, specific examples of the monomer unit represented by the above general formula () are listed below using the structural formula. These thermosetting acrylic polymers may be used by being mixed or copolymerized with styrene, if necessary. Here, X ₂ is

【formula】 or

[Formula] has the property of self-crosslinking, and by applying heat,
It is possible to harden it. However, like those with other functional groups, it is also possible to cure them using curing agents. As the curing agent in the present invention, various types of epoxy resins, alkyd resins having a carboxyl group, or general formula (In the formula, R ₆ , R ₇ and R ₈ represent a hydrogen atom, an alkyl group, a phenyl group, a hydroxyl group, an amino group, an alkyl-substituted amino group or a methylol-substituted amino group, and R ₆ , R ₇ and R ₈ An amine compound having an S-triazine ring (at least one of which represents a methylol-substituted amino group, and the methylol group may be alkyl etherified) or a mixture thereof can be used. Specific examples of amine compounds having such an S-triazine ring are listed below using structural formulas. The charge transport substance in the present invention has the general formula [In the formula, Y is

【formula】

【formula】

[Formula] and

[Formula] represents at least one heterocyclic group selected from the group consisting of (however, Z represents O or S, and the heterocyclic group may be substituted); and R ₉ and R ₁₀ represent an alkyl group having 3 or less carbon atoms] can be applied. Substituents for such heterocyclic groups include lower _alkyl groups such as _-CH3 , _-C2H5 , _-C3H7 , halogens such as -Cl and _-Br , -N( _CH3 ) ₂ , -N
dialkylamino groups such as (C ₂ H ₅ ) ₂ and N(C ₃ H ₇ ) ₂ ;
Further examples include phenyl groups, but the present invention is not limited thereto. Specific examples of such compounds are listed below using structural formulas. The method for synthesizing the above compound is described in Japanese Patent Publication No.
They are described in detail in Japanese Patent Publication No. 11218, Japanese Patent Publication No. 35-11219, etc., and most of these compounds are commercially available as NK dyes from Nippon Kanko Shiki Kenkyusho Co., Ltd. In the present invention, the blending ratio of the monomer units represented by the general formula () and the monomer units represented by the general formula () is not particularly limited, but the latter is preferably 1 to 50% by weight, preferably 3% by weight. ~25% by weight is used. Outside this range, the weather resistance and strength of the binder tend to decrease. In the present invention, the mixing ratio of the thermosetting acrylic polymer and the curing agent is 1 part by weight of the former to 1 part by weight of the latter.
It is appropriate that the amount is within the range of 0.1 to 10 parts by weight, but it is particularly desirable that the amount of the former be 1 part by weight to 4 parts by weight of the latter.
parts by weight or less, and as the latter increases, electrophotographic characteristics (initial potential and half-exposure sensitivity) deteriorate. After mixing, these thermosetting acrylic polymers and curing agents are cured by heating, preferably at a temperature of 100°C or higher and below the melting point of the charge transport material, particularly in an atmosphere of 120°C. Complete hardening can be achieved by heat treatment for 60 minutes. On the other hand, the appropriate mixing ratio of the binder resin and the charge transport substance constituting the charge transport layer is within the range of 0.25 to 2 parts by weight of the charge transport substance per 1 part by weight of the binder resin. If it is less than 0.25 parts by weight, the half-decrease exposure sensitivity decreases, and conversely, if it is more than 2 parts by weight, the initial potential and dark decay decrease. Further, the thickness of the charge transport layer is suitably within the range of 5 to 50 μm; if it is less than 5 μm, the initial potential will be low and durability will be poor. On the other hand, if the thickness exceeds 50 μm, not only the flexibility of the film deteriorates, but also the half-life exposure sensitivity decreases. In addition, as a method for forming the charge transport layer, after thoroughly mixing a thermosetting acrylic polymer as a binder resin and a curing agent, a charge transport substance is added and dissolved by stirring to form a coating liquid. Prepare and coat onto the charge generation layer. Coating is carried out by a generally known method, such as a bar coater, roll coater, applicator, or casting. After coating, the present invention can be achieved by drying the solvent and thermally curing the binder resin. The reason why the binder resin for the charge transport layer of the present invention is superior is not clear, but the binder resin itself is hard (pencil hardness test method (JISD0202)).
3-4H), and that it has good compatibility with charge transporting substances and that it is easy to obtain a uniform film. The charge generating substance used in the present invention includes known organic pigments, dyes, charge transfer complexes, cadmium sulfide, cadmium selenide, arsenic triselenide, antimony trisulfide, cadmium sulfoselenide, zinc sulfide, zinc oxide, and mixtures thereof. It can be selected and used as appropriate. Further, as the conductive support for the composite electrophotographic plate of the present invention, brass, aluminum, gold, steel, etc. can be used, and these may be sheets, thin plates, or thin plates having an appropriate thickness, hardness, or flexibility. It may be cylindrical and may be covered with a thin layer of plastic. or,
This may be metal coated paper, metal coated plastic sheet or glass coated with a thin layer of aluminum iodide, copper iodide or chromium oxide or tin oxide. It is generally desirable that the support be itself electrically conductive or have an electrically conductive surface and be sufficiently strong to handle. Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited by these in any way. Example 1 β-type phthalocyanine pigment (manufactured by Dainippon Ink Co., Ltd.,
2 parts by weight of First Gemble (FGF) and butyral resin (manufactured by Union Carbide, XYHL)
1 part by weight was made into a 6% by weight solution using xylene as a solvent, and kneaded for 5 hours in a ball mill (manufactured by Nihon Kagaku Togyo Co., Ltd., 3-inch pot) to obtain a charge-generating substance coating liquid. Automatic applicator (manufactured by Toyo Seiki Co., Ltd.) on aluminum foil with a film thickness of 100 μm.
A layer of a charge generating substance (charge generating layer) was formed by coating and drying. The thickness of this layer is approximately 3 μm. Next, the thermosetting acrylic polymer of the present invention was synthesized by the following method. A three-necked flask was equipped with a stirrer, a nitrogen inlet, a thermometer, and a reflux condenser. Add 191 parts by weight of dry distilled xylene to the flask and heat to 136°C while slowly flushing with nitrogen. 135 parts by weight methyl methacrylate, 80 parts by weight ethyl acrylate, 30 parts by weight
parts by weight of methacrylic acid, 55 parts by weight

A mixture of 6 parts by weight of di-tert-butyl peroxide and 3 parts by weight of tertiary-dodecyl mercaptan was added over 1.75 hours. Adjust the mantle heater or blow air onto the surface of the flask to bring the temperature to 136°C to 143°C.
The mixture was cooled to 65°C, and then 100 parts by weight of absolute ethanol was added to obtain a thermosetting acrylic polymer solution. The solids content of this solution was 51.3% by weight, and the number average molecular weight was determined to be 6780. Next, to 10 parts by weight of the above solution, 2 parts by weight of an epichlorohydrin-bisphenol A type epoxy resin (manufactured by Ciel Chemical Co., Ltd., Epon828) was added as a curing agent, and toluene was further added as a solvent, so that the solid content was 20% by weight. I made it. To this solution, add a charge transporting substance with the following structural formula (manufactured by Nippon Kanko Shiki Kenkyusho, NK-
Add 10 parts by weight of 1347) and stir. The mixture was completely dissolved to obtain a charge transport substance coating liquid. This coating liquid was applied onto the charge generation layer using an automatic applicator. After coating,
After leaving it in a dryer at 100° C. for 30 minutes to remove the solvent, the temperature of the dryer was further raised and left in an atmosphere at 130° C. for 1 hour to harden the binder resin.
The thickness of the charge transport layer thus obtained was 10 μm. For the composite electrophotographic plate obtained in this example, an electrostatic recording paper tester (manufactured by Kawaguchi Denki Co., Ltd.,
SP-428) was used to evaluate the electrophotographic properties. The evaluation was performed by charging with a 5KV corona discharge for 10 seconds (the surface potential immediately after charging for 10 seconds was V ₀
(V) is the initial potential. ), after leaving it in the dark for 30 seconds (the surface potential at this time is expressed as V ₃₀ (V), and V ₃₀ /V ₀ × 100 (%) is the dark decay), the surface illuminance was set to 2 lx using a tungsten lamp. The attenuation of the surface potential and the time at this time are recorded, and the sensitivity (halving exposure amount E ₅₀ ( _lx・s)).
The characteristics of this electrophotographic plate were such as an initial potential of 930 V, dark decay of 70%, and half-decrease exposure sensitivity of 4 lx·s, which were satisfactory for practical use. When the surface of this electrophotographic plate (the surface of the charge transport layer) was subjected to a pencil hardness test, it was found to be extremely hard with a hardness of 3H. Therefore, when charging exposure was further repeated and changes in characteristics were observed, it was found that after 1000 times, there was almost no decrease in the initial potential or sensitivity, and the product could withstand more than 1000 repetitions. Example 2 A polyester film coated with aluminum (manufactured by Toray Industries, Metal Me, film thickness 50 μm) was used as a support, and the structural formula was A charge generation layer coating liquid with a thickness of 1 μm was formed by using the same coating method as in Example 1, using a solution prepared by dissolving chlorinated Diane Blue represented by ethylenediamine at a concentration of 1% by weight in ethylenediamine. Obtained. Next, using the same thermosetting acrylic polymer solution and epoxy resin as in Example 1, a binder resin for the charge transport layer was prepared in the proportion shown in Table 1 below, and toluene was added to reduce the solid content to 20. Create a solution of % by weight of the charge transport material shown by the structural formula below. A charge transport layer was obtained in the same manner as in Example 1 by adding and dissolving 5 parts by weight to 10 parts by weight of the binder resin. The thickness of this layer is 15 μm. The results of examining the electrophotographic properties of these composite electrophotographic plates are shown in Table 1 below.

【table】

[Table] As is clear from Table 1, as the amount of epoxy resin added increases, the initial potential and half-decrease exposure sensitivity deteriorate. Regarding hardness, 4H was obtained when the amount of epoxy resin added was within the range of 3 to 7 parts by weight. Based on the half-decrease exposure sensitivity and hardness characteristics, an electrophotographic plate containing 3 parts by weight of epoxy resin for 7 parts by weight of solid content of a thermosetting acrylic polymer solution was actually used in a copying machine (manufactured by Ricoh Co., Ltd., P-500). When we installed it and conducted an image forming test, the images obtained were clear and good with no fogging, even after 2000 copies were made in succession. or,
The surface of the composite electrophotographic plate taken out after copying was free from stains and scratches caused by developer and paper, and was found to be highly durable. Example 3 The three-necked flask from 1 was equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a reflux condenser. 245 parts by weight of distilled and dried xylene was placed in this flask, and heated to 136°C with a mantle heater while slowly flowing nitrogen. Next, 50 parts by weight of styrene,
A mixture of 85 parts by weight of methyl methacrylate, 100 parts by weight of 2-ethylhexyl acrylate, 25 parts by weight of oxyethyl methacrylate and 5 parts by weight of di-tert-butyl peroxide was added over a period of 1 hour. Maintain the temperature between 136-140°C by adjusting the mantle heater or blowing air, and keep the temperature at 136-140°C for about 2 hours after adding the monomer mixture.
After cooling, a thermosetting acrylic polymer solution was obtained. The solids content of this solution was 50% by weight and the number average molecular weight was 10,000. Next, 1.5 parts by weight of melamine, 67 parts by weight of commercially available 37% formaldehyde (1/3.3, molar ratio) and 14 parts by weight of water were added.
Parts by weight were added, and the mixture was heated and stirred at 70°C for 1 hour under a counterflow condenser. Note that NaOH was added to adjust the pH of the solution to maintain it at 9.0 during the reaction. After cooling, a portion of this solution was taken out, and free formaldehyde was measured using the sodium sulfite method, and its composition was investigated using paper chromatography. As a result, it was found that hexamethylolmelamine was mainly produced. Therefore, this reaction solution was poured into 2 to 3 times the amount of cold methanol to precipitate crystals, and after over-drying, xylene and butanol (volume ratio 7/3) were added.
A 50% by weight solution of methylolmelamine was obtained. Using the above thermosetting acrylic polymer and curing agent, the binder resin for the charge transport layer was prepared in the proportions shown in Table 2 below, and toluene/methyl ethyl ketone =
7/3 (volume ratio) to create a solution with a solid content of 20% by weight, and add a charge transport substance (manufactured by Nippon Kanko Shiki Kenkyusho Co., Ltd., NK-1343) shown by the following structural formula. The binder resin and charge transport substance were added in a ratio of 2:1 (weight ratio) and dissolved by stirring to obtain a charge transport layer coating liquid. This coating liquid was applied on the same charge generation layer as in Example 2 and cured in the same manner as in Example 1 to form a charge transport layer. The thickness of this layer was approximately 15 μm. Table 2 shows the results of examining the electrophotographic properties of the composite electrophotographic plate thus obtained.

[Table] As is clear from Table 2, as the amount of methylolmelamine added increases, the initial potential and dark decay tend to worsen, but the half-decrease exposure sensitivity is 7:3 was the best. Therefore, when we conducted an image forming test on this composite electrophotographic plate by incorporating it into a copying machine similar to that in Example 2, we found that even after continuously copying 2000 sheets,
The resulting image was clear and good with no fog. Furthermore, the surface of the composite electrophotographic plate taken out after copying was free from stains and scratches caused by developer and paper, and was found to have excellent durability. Example 4 Using the same thermosetting acrylic polymer as in Example 3, a xylene/butanol = 8/2 (volume ratio) solution (solid content 53%) of a compound having the following structural formula as a curing agent as a curing agent, thermosetting acrylic polymer: curing agent = 8:2 (weight ratio) as a binder resin for charge transport layer, and toluene/methyl ethyl ketone = 7/3.
Solutions with different solid contents were prepared by adjusting the amount added (by volume). Next, a charge transport substance having the following structural formula is added in half the amount of the binder resin, and the binder resin:charge transport substance=2:1 (weight ratio) to completely dissolve and transport the charge. A layer coating solution was obtained. This coating liquid was applied onto the same charge generation layer as in Example 2 to obtain composite electrophotographic plates having charge transport layers having various thicknesses. The electrophotographic properties of these electrophotographic plates are shown in Table 3 below.

[Table] As is clear from Table 3, as the film thickness increases, the half-reduction exposure tends to worsen, and it was found that the optimum film thickness is within the range of 5 to 50 μm.
Next, we conducted a continuous image forming test of 1000 sheets on these electrophotographic plates using a copying machine in the same manner as in Example 2, and found that those with a film thickness of 3 μm had a low copy density, and those with a film thickness of 65 μm had a low copy density. However, after copying 300 copies, fogging appeared, and it was found that these two methods were difficult to put to practical use. Other electrophotographic boards are 1000
Even after copying, the images obtained were clear and the electrophotographic plate itself was free from stains and scratches. Example 5 A stirrer, a thermometer,
I installed a reflux condenser. In this flask, 190
A weight part of dry distilled xylene was added and heated to 136°C with a mantle heater while slowly flowing nitrogen. Next, 30 parts by weight of styrene, 105 parts by weight of methyl methacrylate, 75 parts by weight of ethyl acrylate, 60 parts by weight of hydroxyethyl acrylic acid, 30 parts by weight of
A mixture of parts by weight of methacrylic acid, 6 parts by weight of di-tert-butyl peroxide and 3 parts by weight of tertiary dodecyl mercaptan was added over a period of 1.75 hours. Adjust the mantle heater to keep the temperature between 136 and 143℃.
After keeping the mixture for a while, it was cooled to 65°C, and then 100 parts by weight of absolute ethanol was added to obtain a thermosetting acrylic polymer. Next, using methylated methylolmelamine shown in the structural formula below as a curing agent, The above synthesized thermosetting acrylic polymer: curing agent = 7:3 (weight ratio) was used as the binder resin for the charge transport layer, and toluene/methyl ethyl ketone = 7/3.
(by volume) to obtain a solution with a solids content of 16% by weight. To this solution, a charge transport substance having the following structural formula was added in the proportion shown in Table 4 below, and the charge generation layer of Example 2 was formed. A composite electrophotographic plate was obtained in the same manner as in Example 1 (film thickness: about 10 μm). The results of investigating the electrophotographic characteristics of the obtained composite electrophotographic plate are shown in the underlined 4th column.
Shown in the table.

[Table] As is clear from Table 4, as the proportion of the charge transport substance increases, the initial potential and dark decay tend to deteriorate, but the half-decrease exposure sensitivity improves. It was found that the electrophotographic properties required when actually incorporated into a copying machine to form an image are within the range of 0.25 to 2 parts by weight of the charge transport material (per weight of binder resin). . Example 6 The three-necked flask from 1 was equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a reflux condenser, and heated with a mantle heater. This flask was charged with 245 parts by weight of dry distilled xylene and heated to 136° C. under a gentle flow of nitrogen. To this, 135 parts by weight of methyl methacrylate, 50 parts by weight of 2-ethylhexyl acrylate, 50 parts by weight of

A mixture of Glycidyl methacrylate, 25 parts by weight of oxyethyl methacrylate and 5 parts by weight of di-tert-butyl peroxide was added over a period of 1 hour. The temperature was maintained between 136-140°C by adjusting the mantle heater or blowing air. After adding the monomer mixture, the temperature was maintained at 136 to 140° C. for about 2 hours and then cooled to obtain a thermosetting acrylic polymer (solid content: 50% by weight, average molecular weight: 11,000). This thermosetting acrylic polymer contains glycidyl methacrylate and has self-crosslinking properties. Therefore, toluene/methyl ethyl ketone = 7/3 (volume ratio) was added to make the solid content 20% by weight.
Then, a charge transporting substance having the following structural formula was added to this solution to obtain a binder resin:charge transporting substance=2:1. A charge transporting coating liquid was prepared as (weight ratio).
This coating liquid was coated on the same charge generation layer as in Example 1 by the same method as in Example 1 to form a charge transport layer (thickness: 15 μm) to obtain a composite electrophotographic plate. As a result of examining the electrophotographic characteristics of this electrophotographic plate, an initial potential of 910 V, dark decay of 75%, and half-decrease exposure sensitivity of 3.0 lx·s were obtained. Further, when a pencil hardness test was conducted in the same manner as in Example 1, it was found that the material was extremely hard with a hardness of 3H. Furthermore, it is possible to use alkyd resin as a curing agent for this thermosetting acrylic resin (Gritsyl type), so 7 parts by weight of the synthesized thermosetting acrylic polymer is added with a synthetic fatty acid-modified alkyd resin (Hitachi Chemical Co., Ltd.). A solution containing 20% by weight of the binder resin was prepared by adding 3 parts by weight of Phthalkyd 803-70, manufactured by F. Co., Ltd., solid content 70%, and toluene/methyl ethyl ketone = 7/3 (volume ratio). A charge transport layer coating liquid was prepared by adding the substances in a ratio of binder resin: charge transport material = 2:1 (weight ratio). A charge transport layer was formed using this coating liquid on the same charge generation layer as in Example 1 in the same manner as in Example 1 (film thickness: 15 μm). As a result of investigating the electrophotographic characteristics of the composite electrophotographic plate obtained in this way, the initial potential
850V, dark decay of 67%, and half-decrease exposure sensitivity of 3.2lx・s were obtained. Next, a pencil hardness test was conducted in the same manner as in Example 1, and it was found that the hardness was 4H, which was even harder than when acrylic resin was used alone. As explained above, according to the present invention, by applying a binder resin containing a specific thermosetting acrylic polymer to the charge transport layer, a composite electronic device having a charge transport layer with excellent durability can be produced. Photo boards can be provided.

Claims (1)

[Claims] 1. A composite electrophotographic plate comprising a charge generation layer and a charge transport layer laminated on a conductive support, wherein the binder resin contained in the charge transport layer has the general formula [In the formula, R ₁ represents a hydrogen atom or a methyl group,
X ₁ is -COOR ₂ (However, R ₂ is a hydrogen atom, carbon number 4
At least one monomer selected from the group consisting of the following alkyl group or 2-ethylhexyl group) and the general formula [In the formula, R ₃ represents a hydrogen atom or a methyl group,
X ₂ is [Formula] (however, R ₄ represents a hydrogen atom or an alkyl group having 4 or less carbon atoms),
Heat containing at least one monomer selected from the group consisting of monomers represented by [Formula] (wherein R ₅ represents a hydrogen atom or a methyl group) or [Formula]] as its constituent monomer unit. It is made of a curable acrylic polymer, and the charge transport material in the charge transport layer has the general formula [Wherein, Y is at least one heterocyclic group selected from the group consisting of [Formula] [Formula] [Formula] and [Formula] (however, Z represents O or S, and the heterocyclic group is substituted ), n represents 0, 1 or 2, and R ₉ and R ₁₀ represent an alkyl group having 3 or less carbon atoms] Photo board. 2 Epoxy resin, alkyd resin having a carboxyl group, or general formula as a curing agent for the binder resin (In the formula, R ₆ , R ₇ and R ₈ represent a hydrogen atom, an alkyl group, a phenyl group, a hydroxyl group, an amino group, an alkyl-substituted amino group or a methylol-substituted amino group, and R ₆ , R ₇ and R ₈ Claim 1: Addition of an amine compound having an S-triazine ring, at least one of which represents a methylol-substituted amino group, and the methylol group may be alkyl etherified, or a mixture thereof. The described composite electrophotographic plate. 3. The composite electrophotographic plate according to claim 1 or 2, wherein the blending ratio of the curing agent is within the range of 0.1 to 10 parts by weight per 1 part by weight of the binder resin. 4. The composite electrophotographic plate according to any one of claims 1 to 3, wherein the charge transporting substance is blended in a proportion of 0.25 to 2 parts by weight based on 1 part by weight of the binder resin. 5. The composite electrophotographic plate according to any one of claims 1 to 4, wherein the charge transport layer has a thickness in the range of 5 to 50 μm.