JP2518874B2 - Method for manufacturing electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a method for producing an electrophotographic photosensitive member that is preferably used in an image forming apparatus such as a copying machine.

<Problems to be Solved by Conventional Techniques and Inventions> In recent years, it has been widely practiced to form a copied image using an image forming apparatus such as a copying machine utilizing the Carlson process. The Carlson process includes a charging step of uniformly charging a photoconductor by corona discharge, an exposure step of exposing a document image on the charged photoconductor to form an electrostatic latent image corresponding to the document image, and an electrostatic latent image. Is developed with a developer containing toner to form a toner image, a transfer step of transferring the toner image to a base material such as paper, a fixing step of fixing the toner image transferred to the base material, After the transfer step, the cleaning step of removing the toner remaining on the photoconductor is included as a basic step. In the above Carlson process, the electrical, optical, and mechanical loads are repeatedly applied to the photoconductor. In order to continuously form a high-quality image, it is necessary that the photosensitive layer of the photoconductor does not deteriorate due to the above action and has durability.

On the other hand, as a photoconductor in the image forming apparatus, an organic photoconductor having a wide selection of materials, excellent productivity, and a high degree of freedom in functional design is widely adopted. More specifically,
On a conductive substrate, a charge generation layer containing a charge generation substance that generates a charge by the exposure in the exposure step is generated in order to separate the charge generation function and the charge transport function to achieve high sensitivity, and generated. There has been proposed an electrophotographic photoreceptor having a laminated photosensitive layer in which a charge transporting substance that transports charges and a charge transporting layer containing a binder resin are laminated. The electrophotographic photoreceptor having the laminated photosensitive layer is usually a coating solution for a charge generating layer containing a thermoplastic resin such as polycarbonate, polyester, acrylic resin and the charge generating substance, the thermoplastic resin and the charge. A coating solution for a charge transport layer containing a transporting substance is prepared respectively, one coating solution is applied to a conductive base material and, if necessary, dried by heating, and then the other coating solution is applied and dried by heating. It is manufactured by

However, when the above-mentioned thermoplastic resin is used as a binder resin for a laminated type photosensitive layer, it is difficult to form a uniform photosensitive layer. More specifically, a laminated type photosensitive layer in which a charge transport layer and a charge generation layer are sequentially formed will be described as an example. A charge transport layer coating liquid was applied on a conductive substrate to form a charge transport layer. After that, when the coating solution for the charge generating layer is applied on the charge transporting layer, the charge transporting material has good solubility in the solvent in the coating solution and the charge transporting layer is a thin film. The organic solvent in the coating solution elutes the charge transport material in the charge transport layer, and the eluted charge transport layer material is deposited at the interface between the charge transport layer and the charge generating layer to form a uniform photosensitive layer. It is difficult to separate each function. Contrary to the above, even in a laminated type photosensitive layer having a structure in which a charge generation layer and a charge transport layer are sequentially stacked on a conductive substrate, the charge generation layer usually has a thickness of the charge transport layer. Since it is smaller than the above, the thermoplastic resin in the charge generation layer is eluted and it is difficult to form a uniform charge generation layer and charge transport layer.

In view of the above points, it has been proposed to use a thermosetting resin as a binder resin of a lower layer in contact with a conductive base material in a photoreceptor having a laminated photosensitive layer.

According to the above-mentioned photosensitive layer, the thermosetting resin in the lower layer in contact with the conductive base material can be cured and the solubility in the organic solvent in the upper layer coating solution can be reduced, so that the upper layer coating solution is applied. In this case, there is an advantage that the elution of the charge transport substance and the binder resin can be suppressed and an electrophotographic photoreceptor having a uniform photosensitive layer can be obtained.

However, since it is a thermosetting resin in which the binder resin in the lower layer of the laminated type photosensitive layer is cross-linked, its affinity with the coating liquid for the upper layer is lowered, and the adhesiveness between the lower layer and the upper layer is insufficient, so that it can be used repeatedly. As a result, the photosensitivity and electrical characteristics deteriorate,
There is a problem that it is difficult to form a high quality image for a long period of time.

On the other hand, in order to improve the adhesiveness between the lower layer and the upper layer of the laminated photosensitive layer, it has been proposed to form various primer layers or a resin layer containing a resin having excellent adhesiveness between the both layers.

However, according to the method of forming the primer layer and the resin layer, not only the number of coating steps is increased and the productivity is lowered, but also the cost of the photoconductor is increased. Further, since the primer layer and the resin layer have low electric conductivity, there is a problem that they adversely affect the photosensitivity and the electrical characteristics, the sensitivity is lowered, and the residual potential is increased.

<Objects of the Invention> The present invention has been made in view of the above problems, and is excellent in the adhesion between the conductive substrate and the photosensitive layer and between the layers and the homogeneity of the laminated photosensitive layer, and also provides a high-quality image for a long time. It is an object of the present invention to provide a method for producing an electrophotographic photoconductor, which is capable of producing an electrophotographic photoconductor capable of forming an electrophotographic photoconductor at low cost without adversely affecting sensitivity characteristics and electrical characteristics.

<Means and Actions for Solving Problems> In order to achieve the above object, the method for producing an electrophotographic photoreceptor according to the present invention includes a charge generating layer and a charge transporting layer on a conductive substrate. One is a method for producing a photoreceptor having a laminated photosensitive layer formed as a lower layer, which comprises at least a thermosetting resin and / or a photocurable resin and a thermoplastic resin on a conductive base material. It is characterized in that the lower layer coating liquid is applied, at least a part of the thermosetting resin and / or the photocurable resin is cured, and then the upper layer coating liquid containing at least a thermoplastic resin is applied.

According to the method for producing an electron true photoconductor having the above-mentioned configuration, a lower layer coating liquid containing at least a thermosetting resin and / or a photocurable resin and a thermoplastic resin is applied on the conductive substrate, Since at least a part of the thermosetting resin and / or the photocurable resin is cured, the resin in the lower layer has a cross-linking structure, the solubility in the solvent in the coating liquid for the upper layer is lowered, and the coating for the upper layer is performed. Elution of the charge transport material, the binder resin, and the like in the lower layer due to the solvent in the liquid is suppressed, and a uniform laminated photosensitive layer can be formed. Further, when the upper layer coating liquid containing at least a thermoplastic resin is applied to the lower layer, the thermoplastic resin contained in the lower layer swells with the solvent in the upper layer coating liquid, and the thermoplastic resin in the upper layer coating liquid Since the resin penetrates into the lower layer, the resin in the coating solution for the upper layer is bonded to the lower layer in an anchoring state, and the adhesion between the lower layer and the upper layer is enhanced.

 The present invention will be described in detail below.

The electrophotographic photoreceptor of the present invention is obtained by applying a lower layer coating liquid containing at least a thermosetting resin and / or a photocurable resin and a thermoplastic resin to a conductive substrate, It comprises a step of curing at least a part and a step of applying an upper layer coating liquid containing at least a thermoplastic resin to a lower layer containing a thermosetting resin or the like that is at least partially cured.

The lower layer coating solution and the upper layer coating solution are appropriately used depending on the laminated form of the laminated photosensitive layer. That is, in a laminated type photosensitive layer in which a charge transport layer is laminated on a charge generating layer, a coating liquid containing a charge generating substance, the thermosetting resin and the like and a thermoplastic resin is used as a lower layer coating liquid. The coating liquid containing the charge transport substance and the thermoplastic resin may be used as the coating liquid for the upper layer. Contrary to the above,
In the laminate type photosensitive layer in which the charge generation layer is laminated on the charge transport layer, a coating solution containing a charge transporting material, the thermosetting resin and the like and a thermoplastic resin is used as the lower layer coating solution, A coating liquid containing a charge generating substance and a thermoplastic resin may be used as the coating liquid for the upper layer.

The conductive substrate may be in the form of a sheet or a drum having conductivity, various materials having conductivity, for example, aluminum, aluminum alloy,
A single metal such as copper, tin, platinum, gold, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, or brass, or the above metal, indium oxide, tin oxide, etc. by means of vapor deposition or the like. Examples of the plastic material and glass, etc., on which the conductive layer of (1) are formed. Among the above-mentioned conductive base materials, those having an oxide surface, in particular, alumite-treated aluminum, in particular, an alumite-treated layer having a film thickness of 5 to 12 μm and a surface roughness in order to enhance adhesion with a photosensitive layer. Is preferably 1.5 A or less and anodized aluminum.

Examples of the charge generating substance contained in the charge generating layer include selenium, selenium-tellurium, amorphous silicon, pyrylium salts, azo compounds, disazo compounds, phthalocyanine compounds, anthanthrone compounds, and perylene compounds. , Indigo compounds, triphenylmethane compounds, slene compounds, toluidine compounds, pyrazoline compounds, perylene compounds, quinacridone compounds, pyrrolopyrrole compounds and the like. The charge generating substance may be used alone or in combination of two or more. The charge generating substance can be appropriately selected, but in order to enhance the spectral sensitivity, a phthalocyanine compound, for example, α-type, β-type, γ-type, etc., aluminum phthalocyanine having various crystal types, copper phthalocyanine,
Among them, those containing metal-free phthalocyanine and / or titanyl phthalocyanine are preferable.

Examples of the charge transport material include tetracyanoethylene, fluorenone compounds such as 2,4,7-trinitro-9-fluorenone, nitration compounds such as 2,4,8-trinitrothioxanthone and dinitroanthracene, and anhydrous compounds. Succinic acid, maleic anhydride, dibromomaleic anhydride,
Oxadiazole compounds such as 2,5-di (4-dimethylaminophenyl) -1,3,4-oxadiazole, 9- (4
-Styryl compounds such as diethylaminostyryl) anthracene, carbazole compounds such as polyvinylcarbazole, pyrazoline compounds such as 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline, 4,4 ', 4 "
-Aromatic amine derivatives such as tris (N, N-diphenylamino) triphenylamine and 4,4'-bis [N-phenyl-N- (3-methylphenyl) amino] diphenyl, 1,1-bis (4 -Diethylaminophenyl) -4,4-
Nitrogen-containing compounds such as conjugated unsaturated compounds such as diphenyl-1,3-butadiene, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, triazole compounds, etc. Cyclic compounds,
Examples include fused polycyclic compounds and the like. The charge transport material may be used alone or in combination of two or more. In addition, a photoconductive polymer as the charge transport material, such as poly-N-vinylcarbazole, may be used as the thermoplastic resin.

Further, as the thermosetting resin, various ones, for example, acrylic resin, alkyd resin, unsaturated polyester, polyurethane, epoxy resin, diallyl phthalate resin, silicone resin, phenol resin, urea resin, benzoguanamine resin, melamine resin, etc. Is exemplified.
The thermosetting resins may be used alone or in combination of two or more.

Further, as the photocurable resin, an epoxy acrylate obtained by an addition reaction of an epoxy resin and a compound having a reactive group with an epoxy group such as acrylic acid and an unsaturated bond group, polyisocyanate such as tolylene diisocyanate Urethane acrylate obtained by reacting a compound, a compound having a reactive group with an isocyanate group such as 2-hydroxyethyl acrylate and an unsaturated bond group, and a polyol component, if necessary, a polyvalent carboxylic acid and a polyvalent Alcohol and acrylic acid or 2
Examples thereof include polyester acrylates obtained by reaction with hydroxyethyl acrylate and methacrylates corresponding to these. The above photocurable resins may be used alone or in combination of two or more.

The thermosetting resin and the photocurable resin may be used in combination. Further, the thermosetting resin can be cured using a conventionally used curing agent depending on the type of resin. Further, the photocurable resin can be cured using a conventionally used photopolymerization initiator, and in order to adjust the characteristics of the polymer film,
A photopolymerizable monomer such as ethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, or a methacrylate corresponding to these may be used in combination.

As the thermoplastic resin, for example, a styrene-based polymer,
Acrylic polymer, styrene-acrylic copolymer, polyethylene, ethylene-vinyl acetate copolymer, chlorinated polyethylene, polypropylene, olefin polymers such as ionomer, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, Examples include saturated polyester, polyamide, polyurethane, polycarbonate, polyarylate, polysulfone, ketone resin, polyvinyl butyral resin, and polyether resin, and these thermoplastic resins may be used alone or in combination of two or more.

The photosensitive layer is made of a conventionally known sensitizer such as terphenyl, halonaphthoquinones, acenaphthylene, and 9- (N, N
Various additives such as a fluorene compound such as -diphenylhydrazino) fluorene and 9-carbazolyliminominofluorene, a plasticizer, an antioxidant, and an antiaging agent such as an ultraviolet absorber may be contained.

Then, a lower layer coating liquid containing at least a thermosetting resin and / or a photocurable resin and a thermoplastic resin together with one of the charge generating substance and the charge transporting substance is added to the conductive base material. It is applied to cure at least a part of the thermosetting resin. In order to prevent the resin in the lower layer from being eluted by the solvent in the coating liquid for the upper layer, at least a part of the thermosetting resin and / or the photocurable resin in the lower layer may be cured. It is preferable to completely cure the thermosetting resin and / or the photocurable resin in order to further suppress the elution of the thermoplastic resin and the like in the lower layer and form the laminated photosensitive layer uniformly.

The thermosetting resin in the lower layer, can be cured under appropriate conditions depending on the curing characteristics of the thermosetting resin, usually, at room temperature to about 150 ℃ temperature conditions, by heating for a suitable time However, in order to efficiently and completely cure the thermosetting resin, it is preferable to cure at a temperature higher than the curing temperature.

The photocurable resin can be cured by adjusting the light intensity and the light irradiation time according to the photocurability. Further, in order to prevent photopolymerization due to oxygen molecules, the photocurable resin may be cured in the presence of an inert gas.

The ratio of the thermosetting resin and / or the photocurable resin to the thermoplastic resin in the lower layer coating liquid is
It can be appropriately set according to the type of thermoplastic resin, but the lower layer coating liquid contains 10 to 10 thermoplastic resins in the resin.
It is preferable to contain 60% by weight, particularly 20 to 50% by weight. If the amount of the thermoplastic resin in the resin is less than 10% by weight, the adhesion between the lower layer and the upper layer will decrease, and if it exceeds 60% by weight, the elution of the upper layer coating liquid by the solvent will increase and the coatability will decrease. Then
It is difficult to form a laminated photosensitive layer having excellent homogeneity.

Further, the thermoplastic resin contained in the lower layer may have an appropriate molecular weight depending on the type of the resin and its solubility, but the degree of swelling by the solvent in the coating liquid for the upper layer is increased. In order to efficiently permeate the thermoplastic resin in the coating liquid for the upper layer into the lower layer, a weight average molecular weight of 10,000 to 60,000, particularly
Those having 20,000 to 40,000 are preferred. If the weight average molecular weight of the thermoplastic resin is less than 10,000, the thermoplastic resin in the lower layer is likely to be eluted, and if it exceeds 60,000, the swelling degree of the thermoplastic resin in the lower layer is small, and the adhesion between the lower layer and the upper layer is sufficient. Difficult to raise.

Next, the upper layer coating liquid containing at least the thermoplastic resin is applied to the lower layer containing the thermosetting resin or the like at least partially cured as described above. The above coating solution for the upper layer may contain at least a thermoplastic resin,
You may contain the said thermosetting resin and the photocurable resin with the said thermoplastic resin. Incidentally, when partially curing the thermosetting resin of the lower layer, or when using a coating liquid containing a thermosetting resin or a photocurable resin as the coating liquid for the upper layer, the coating liquid for the upper layer in the lower layer After applying
It is only necessary to heat or irradiate light to cure the thermosetting resin or the like contained in the lower layer in a partially cured state or the thermosetting resin in the coating liquid for the upper layer. When the upper layer coating liquid contains only a thermoplastic resin as the binder resin, the solvent may be removed and dried after applying the upper layer coating liquid.

Incidentally, the thermoplastic resin in the coating solution for the upper layer is not particularly limited, among the resins exemplified above, an appropriate one can be used,
The thermoplastic resin in the lower layer coating liquid and the thermoplastic resin in the upper layer coating liquid are preferably the same kind in order to promote penetration into the lower layer of the thermoplastic resin and enhance sensitivity.

By applying the coating solution for the upper layer as described above, at least a part of the thermosetting resin or the like contained in the lower layer has been cured, and therefore the charge transport substance in the lower layer due to the solvent in the coating solution for the upper layer. And the elution of resin, etc. can be suppressed, the thermoplastic resin in the lower layer swells, and the thermoplastic resin in the coating solution for the upper layer permeates the thermoplastic resin in the swollen state. It is possible to bring the layer into close contact with the upper layer and to form a homogeneous photosensitive layer composed of the lower layer and the upper layer.

When preparing the above-mentioned coating liquid, various organic solvents can be used depending on the type of resin used. Examples of the solvent include aliphatic hydrocarbons such as n-hexane, octane and cyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, carbon tetrachloride and chlorobenzene, dimethyl ether, and the like. Diethyl ether,
Tetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol dimethyl ether, dimethylene glycol dimethyl ether, and other ethers, acetone, methyl ethyl ketone, cyclohexanone, and other ketones, ethyl acetate, methyl acetate, and other esters, dimethylformamide, dimethyloxide, various solvents Are exemplified, and one kind or a mixture of two or more kinds is used. In addition,
When using a photocurable resin, the above solvent is not always necessary. Further, when preparing the coating liquid or the like, dispersibility,
In order to improve coatability and the like, a surfactant, a leveling agent and the like may be used in combination.

Further, the coating solution can be prepared by a conventional method, for example, using a mixer, a ball mill, a paint shaker, a sand mill, an attritor, an ultrasonic disperser, etc., and the obtained coating solution as described above. The electrophotographic photosensitive member of the present invention can be obtained by applying it to a conductive substrate and curing it by heating.

When the charge generation layer in the laminated photosensitive layer is formed on the conductive substrate or the charge transport layer, the ratio of the charge generation substance to the resin in the charge generation layer can be appropriately set. It is preferable to use 5 to 5000 parts by weight, especially 10 to 2500 parts by weight, of the charge generating substance with respect to 100 parts by weight of the resin. If the amount of the charge generating substance is less than 5 parts by weight, the charge generating ability is low, and if it exceeds 5000 parts by weight, there is a problem that the adhesion is reduced. The charge generation layer may have an appropriate thickness, but preferably has a thickness of about 0.01 to 30 μm, particularly about 0.1 to 20 μm.

Further, the ratio of the charge transport material to the resin in the charge transport layer can be appropriately set, but the charge transport material is preferably 10 to 500 parts by weight, particularly 25 to 20 parts by weight with respect to 100 parts by weight of the resin. preferable. If the amount of the charge transporting substance is less than 10 parts by weight, the charge transporting ability is not sufficient, and if it exceeds 500 parts by weight, the mechanical strength of the charge transporting layer is reduced. The charge transport layer may have an appropriate thickness, but is 2 to 100 μm.
Those having a thickness of m, particularly about 5 to 30 μm are preferable.

Furthermore, the charge generation layer in the laminated photosensitive layer may contain the above charge transport material. When the charge-generating layer contains a charge-transporting substance, the ratio of the charge-generating substance, the charge-transporting substance, and the resin is not particularly limited, and can be appropriately selected according to the desired characteristics of the electrophotographic photoreceptor. However, 2 to 20 parts by weight of the charge generating substance, particularly 3 to 15 parts by weight, 40 to 200 parts by weight of the charge transporting substance, relative to 100 parts by weight of the resin,
It is particularly preferably 50 to 100 parts by weight. If the amount of the charge-generating substance and the charge-transporting substance is less than the above amount, not only the sensitivity of the photoconductor is insufficient but also the residual potential becomes large. If it exceeds the above range, the abrasion resistance of the photoconductor becomes insufficient. Since the charge generation layer containing the above charge transport substance contains the charge transport substance, the film thickness can be increased unlike the charge generation layer containing only the charge generation substance. Forming it on the surface layer has the advantage of not requiring a surface protection layer. The charge generation layer containing the above charge transport material can be formed to have an appropriate thickness, but is usually formed to have a thickness of about 0.1 to 50 μm.

In order to increase the adhesion between the conductive substrate and the photosensitive layer, an undercoat layer may be formed between the conductive substrate and the photosensitive layer. The undercoat layer is formed such that a solution containing a natural or synthetic polymer is applied and the film thickness after drying is about 0.01 to 1 μm. Further, in order to enhance the adhesion between the conductive base material and the photosensitive layer, the conductive base material may be treated with a surface treatment material such as a silane coupling agent or a titanium coupling agent. Furthermore, in order to protect the photosensitive layer,
A surface protective layer may be formed on the photosensitive layer. The surface protective layer is formed by applying the above-mentioned various resins or a mixed solution of the resins and additives such as a deterioration inhibitor to a film thickness of 0.1 to 10 μm after drying, preferably about 0.2 to 5 μm. To be done.

The method for producing an electrophotographic photoreceptor of the present invention comprises applying a lower layer coating liquid containing at least a thermosetting resin or a photocurable resin and a thermoplastic resin onto a conductive base, and then applying the thermosetting resin. Alternatively, since at least a part of the photocurable resin is cured, the upper layer coating liquid containing at least a thermoplastic resin is applied, and thus the upper layer in a state in which the solubility in the solvent in the upper layer of the resin in the lower layer is reduced. Can be formed. At that time, in the thermoplastic resin of the lower layer swollen by the solvent in the coating solution for the upper layer, since the thermoplastic resin in the coating for the upper layer penetrates, it is said that the adhesion between the lower layer and the upper layer is increased,
It is possible to form an electrophotographic photoreceptor capable of forming a uniform laminated type photosensitive layer, exhibiting excellent photosensitivity and electrical characteristics for a long period of time and capable of forming high quality images. Further, since it is not necessary to form a resin layer or the like between the lower layer and the upper layer, which may adversely affect the photosensitive characteristics and the electrical characteristics, the electrophotographic photosensitive member can be inexpensively manufactured without increasing the coating process. It can be manufactured. Therefore, the present invention is effective in manufacturing an electrophotographic photosensitive member used in a copying machine, a laser beam printer, or the like.

<Examples> Hereinafter, the present invention will be described in more detail with reference to Examples.

Comparative Example 1 4- (N, N-diethylamino) benzaldehyde N, N
-Diphenylhydrazone 10 parts by weight, acrylic polyol (manufactured by Dainippon Ink and Chemicals, trade name Acridic 53-8
9) 105.2 parts by weight of a thermosetting urethane resin consisting of 75.2% by weight and an isocyanate curing agent (manufactured by Dainippon Ink Kogyo Co., Ltd., trade name: Barnock D-750) 24.8% by weight, and a predetermined amount of dichloromethane are stirred and mixed to charge A coating liquid for the transport layer was prepared. The thermosetting urethane resin is 110
It has the ability to cure by heating at a temperature of ℃ for 30 minutes.

1 part by weight of dibromoanthanthrone, 10 parts by weight of 4- (N, N-diethylamino) benzaldehyde N, N-diphenylhydrazone, bisphenol A type polycarbonate (manufactured by Teijin Chemicals, trade name Panlite L-1225M, weight average molecular weight 20000- (30000) 10 parts by weight and a predetermined amount of dichloromethane were charged in a ball mill and mixed and dispersed for 2 hours to prepare a coating solution for a charge generation layer containing a charge transport material.

And on the aluminum base material that has been anodized,
The charge transport layer coating solution was applied and heated at a temperature of 110 ° C. for 30 minutes to form a charge transport layer having a thickness of about 30 μm. Then, the charge transport layer coating solution is applied to the charge transport layer.
The film thickness is about 15μ by drying at 100 ℃ for 30 minutes.
A charge generation layer of m was formed to prepare an electrophotographic photoreceptor having a laminated photosensitive layer.

Example 1 Instead of 10 parts by weight of the thermosetting urethane resin used in Comparative Example 1, 9 parts by weight of the thermosetting urethane resin of Comparative Example 1 and 1 part by weight of the polycarbonate used for preparing the coating liquid for the charge generation layer were used. A coating liquid for charge transport layer was prepared in the same manner as in Comparative Example 1 above. Then, the charge transport layer coating liquid,
Using the charge generation layer coating liquid of Comparative Example 1, the above Comparative Example 1 was used.
An electrophotographic photosensitive member having a laminated photosensitive layer was prepared in the same manner as in.

Example 2 Instead of 10 parts by weight of the thermosetting urethane resin used in Comparative Example 1, 7.5 parts by weight of the thermosetting urethane resin of Comparative Example 1,
Polycarbonate used to prepare the coating liquid for the charge generation layer 2.
A charge transport layer coating solution was prepared in the same manner as in Comparative Example 1 using 5 parts by weight. Then, using the above-mentioned charge transport layer coating liquid and the charge generating layer coating liquid of Comparative Example 1, an electrophotographic photoreceptor having a laminated photosensitive layer was prepared in the same manner as in Comparative Example 1.

Example 3 Instead of 10 parts by weight of the thermosetting urethane resin used in Comparative Example 1, 5 parts by weight of the thermosetting urethane resin of Comparative Example 1 and 5 parts by weight of the polycarbonate used for preparing the coating liquid for the charge generation layer were used. A coating liquid for charge transport layer was prepared in the same manner as in Comparative Example 1 above. Then, the charge transport layer coating liquid,
Using the charge generation layer coating liquid of Comparative Example 1, the above Comparative Example 1 was used.
An electrophotographic photosensitive member having a laminated photosensitive layer was prepared in the same manner as in.

Example 4 Instead of 10 parts by weight of the thermosetting urethane resin used in Comparative Example 1, 8 parts by weight of the thermosetting urethane resin of Comparative Example 1 and polymethylmethacrylate (trade name BR10 manufactured by Mitsubishi Rayon Co., Ltd.) were used.
1) A coating solution for a charge transport layer was prepared in the same manner as in Comparative Example 1 using 2 parts by weight. Then, using the above-mentioned charge transport layer coating liquid and the charge generation layer coating liquid of Comparative Example 1, an electrophotographic photoreceptor having a laminated photosensitive layer was prepared in the same manner as in Comparative Example 1.

Example 5 A laminated photosensitive layer was formed in the reverse form of the photosensitive layer of Example 1 above. That is, 20 parts by weight of dibromoanthanthrone used in Comparative Example 1, 8 parts by weight of thermosetting urethane resin, 2 parts by weight of polycarbonate of Comparative Example 1 and a predetermined amount of dichloromethane were charged into a ball mill and mixed and dispersed for 24 hours, A charge generation layer coating solution was prepared. Further, 10 parts by weight of 4- (N, N-diethylamino) benzaldehyde N, N-diphenylhydrazone of Comparative Example 1, 10 parts by weight of polycarbonate, and a predetermined amount of dichelolomethane were mixed by stirring to prepare a coating liquid for the charge transport layer. . Then, the charge generation layer coating solution is applied to the aluminum substrate used in Comparative Example 1 and heat-cured in the same manner as in Comparative Example 1 to form a charge generation layer having a film thickness of about 15 μm, and after the charge transport. The layer coating solution was applied and dried to form a charge transport layer having a thickness of about 30 μm, and an electrophotographic photoreceptor having a laminated photosensitive layer having a negative charging laminated photosensitive layer was prepared.

Example 6 Instead of 10 parts by weight of the thermosetting urethane resin used in Comparative Example 1, 8 parts by weight of the thermosetting urethane resin of Comparative Example 1, bisphenol Z type polycarbonate (trade name Polycarbonate Z, manufactured by Mitsubishi Gas Chemical Co., Inc., Weight average molecular weight 20000
~ 30000) 2 parts by weight was used to prepare a charge transport layer coating solution in the same manner as in Comparative Example 1 above. Then, using the above-mentioned charge transport layer coating liquid and the charge generation layer coating liquid of Comparative Example 1, an electrophotographic photoreceptor having a laminated photosensitive layer was prepared in the same manner as in Comparative Example 1.

Example 7 Instead of the polycarbonate of Example 6 above, bisphenol Z type polycarbonates having different molecular weights (manufactured by Mitsubishi Gas Chemical Co., Inc., trade name Polycarbonate Z, weight average molecular weight)
60000) was used to prepare a charge transport layer coating solution in the same manner as in Comparative Example 1 above. Then, using the above-mentioned charge transport layer coating liquid and the charge generation layer coating liquid of Comparative Example 1, an electrophotographic photoreceptor having a laminated photosensitive layer was prepared in the same manner as in Comparative Example 1.

Example 8 Instead of 10 parts by weight of the thermosetting urethane resin of Comparative Example 1,
Acrylic UV curable resin (trade name M, manufactured by Koei Chemical Co., Ltd.
-1) Using 8 parts by weight and 2 parts by weight of the polycarbonate of Comparative Example 1, a coating liquid for charge transport layer was prepared in the same manner as in Comparative Example 1 above. Then, using the above-mentioned charge transport layer coating liquid and the charge generation layer coating liquid of Comparative Example 1, an electrophotographic photoreceptor having a laminated photosensitive layer was prepared in the same manner as in Comparative Example 1. The UV curable resin contained in the charge transport layer was cured by irradiation with a metal halide lamp of 120 W / cm from a height of 10 cm for 60 seconds (irradiation amount of 2.5 to 3.0 J / cm ² ).

Comparative Example 2 Instead of the thermosetting urethane resin of Comparative Example 1, Comparative Example 1
In the same manner as in Comparative Example 1 described above, a charge transporting layer coating solution was prepared using the above polycarbonate, and the resulting charge transporting layer coating solution and the charge generating layer coating solution in Comparative Example 1 were used. An electrophotographic photoreceptor having a laminated photosensitive layer was produced.

Then, in order to examine the charging characteristics and the photosensitive characteristics of the electrophotographic photoreceptors having the laminated photosensitive layers obtained in the above Examples and Comparative Examples, an electrostatic copying paper test apparatus (Kawaguchi Electric Co., SP-42
8 type) was used to perform corona discharge under the condition of +6.0 KV to positively charge the electrophotographic photoconductors of the respective Examples and Comparative Examples. In the photoconductor of Example 5, the electrophotographic photoconductor was negatively charged under the condition of -6.0 KV.

Also, while measuring the surface potential Vs.p. (V) of each photoconductor, the surface of the photoconductor is exposed using a tongue lamp with an illumination of 10 lux until the surface potential Vs.p. becomes 1/2. Then, the half-exposure amount E 1/2 (Lux. · Sec.) Was calculated. Further, the surface potential after 0.15 seconds has elapsed after the exposure was defined as the residual potential Vr.p. (V).

Further, in order to examine the adhesion between the alumite-treated aluminum base material and the photosensitive layer, the photosensitive layer of the photoreceptor of each of the Examples and Comparative Examples was cross-cut to form 100 cross-cuts, and an adhesive tape Momentarily pulling away from one end,
The number of grids that did not peel off was counted and the adhesion was evaluated.

Also, when the upper layer coating solution is applied to the lower layer, it is visually judged whether or not the charge transport substance is eluted, and the one that is significantly eluted is ×, the one that is slightly eluted is Δ, and any change is observed. Those that did not exist were evaluated as ◯.

The results of the charging characteristics, the photosensitive characteristics, etc. of the electrophotographic photoreceptors obtained in the above Examples and Comparative Examples are shown in the table.

As is clear from the table, in the photosensitive layer of Comparative Example 1 in which the lower layer did not contain a thermoplastic resin, the charge generation layer was peeled from the charge transport layer, and it was found that the adhesion was not sufficient. Further, in the photoconductor of Comparative Example 2 in which the lower layer does not contain a thermosetting resin, the charge transport substance in the charge transport layer was eluted during the production of the photoconductor and the crystals of the charge transport substance were deposited, so that the photoconductive layer was non-uniform. It turned out that the sensitivity was not sufficient.

On the other hand, in the photoconductors of the examples, the lower layer contains a thermosetting resin or a photocurable resin and a thermoplastic resin, and the upper layer contains a thermoplastic resin, so both are conductive. It was found that the adhesiveness between the conductive base material and the photosensitive layer and the adhesiveness between the charge transport layer and the charge generation layer were excellent.

<Effects of the Invention> As described above, according to the method for producing an electrophotographic photosensitive member of the present invention, the lower layer coating liquid containing at least a thermosetting resin or a photocurable resin and a thermoplastic resin is used as the conductive material. Is applied on a thermosetting substrate, and at least a part of the thermosetting resin or the photocurable resin is cured, and then an upper layer coating solution containing at least a thermoplastic resin is applied. It is possible to suppress the elution of charge-transporting substances and resins in the lower layer due to the solvent, and to form a homogeneous laminated photosensitive layer, and at the same time, in the swollen thermoplastic resin in the lower layer, the thermoplastic resin in the coating liquid for the upper layer Penetrates into the base layer, so that the adhesiveness between the lower layer and the upper layer is excellent. Therefore, an electrophotographic image which is excellent in the adhesion between the conductive substrate and the photosensitive layer and the photosensitive layer, the homogeneity of the laminated type photosensitive layer, the sensitivity characteristic, and the electrical characteristic, and which can form a high-quality image for a long time There is a peculiar effect that the photoconductor for use can be manufactured at low cost.

Continuation of the front page (56) Reference JP-A-58-17448 (JP, A) JP-A-57-208558 (JP, A) JP-A-60-104953 (JP, A) JP-A-58-31338 (JP , A)

Claims (4)

(57) [Claims] 1. A method for producing a photoconductor having a laminated photosensitive layer having a charge generation layer or a charge transport layer formed as a lower layer on a conductive base material. On top, apply a lower layer coating liquid containing at least a thermosetting resin or a photocurable resin and a thermoplastic resin, after curing at least a part of the thermosetting resin or the photocurable resin, at least A method for producing an electrophotographic photosensitive member, which comprises applying an upper layer coating liquid containing a thermoplastic resin. 2. The lower layer coating liquid comprises a thermoplastic resin in the resin.
The method for producing an electrophotographic photosensitive member according to claim 1, which contains 10 to 60% by weight. 3. The method for producing an electrophotographic photoreceptor according to claim 1 or 2, wherein the thermoplastic resin in the lower layer coating liquid has a weight average molecular weight of 10,000 to 60,000. 4. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the thermoplastic resin of the lower layer coating liquid and the thermoplastic resin of the upper layer coating liquid are of the same type.