JP5401188B2 - Method for producing electrophotographic photosensitive member - Google Patents

Description

  The present invention relates to a method for producing an electrophotographic photoreceptor having an organic photosensitive layer.

An electrophotographic photosensitive member (hereinafter also referred to as a “photosensitive member”) used in an electrophotographic image forming apparatus (also referred to as an “electrophotographic device”) that is frequently used in digital multi-function peripherals, printers, and the like is mounted on a conductive support. A photosensitive layer containing a photoconductive material is laminated on the surface, and an inorganic photoconductive material such as selenium has been conventionally used as the photoconductive material.
On the other hand, the organic photoconductive material is slightly inferior in terms of sensitivity, durability and stability to the environment as compared with the inorganic photoconductive material, but from the viewpoint of toxicity, manufacturing cost, freedom of material design, etc. In recent years, it has been widely used.

In addition, the structure of the photoreceptor has changed from a single layer type in which a charge generation material and a charge transport material are dispersed in a binder resin to a functional separation type in which the charge generation layer and the charge transport layer are separated, and the performance is also improved. It is improving.
At present, the mainstream is a configuration in which an intermediate layer, a stacked type (functional separation type) photosensitive layer in which a charge generation layer and a charge transport layer are stacked in this order are stacked in this order on a conductive support. It has become.
The intermediate layer can improve the adhesion of the photosensitive layer by coating defects on the conductive support, improve the film formability (coatability), prevent unnecessary charge injection from the conductive support, and improve the chargeability associated therewith. It has the function of.

An intermediate | middle layer is divided roughly into what consists of resin independent, and what consists of resin containing the pigment.
Examples of the resin used for the intermediate 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 a thermosetting resin that forms a network structure.

However, since water-soluble resins and alcohol-soluble resins are rich in moisture adsorption and affinity, there is a problem that physical properties are extremely dependent on the environment, and the characteristics of the photoreceptor are changed by humidity. In particular, since the intermediate layer absorbs a large amount of moisture at high humidity, repeated use of the photoreceptor at high temperature and high humidity or low temperature and low humidity greatly changes its characteristics and causes abnormal images such as black spots and density reduction.
Therefore, a thermosetting resin that forms a three-dimensional network structure excellent in solvent resistance and environmental stability was adopted.

  However, for example, melamine resins disclosed in Japanese Patent No. 3657138 (Patent Document 1), for example, resins such as phenol resin and methoxymethylated nylon disclosed in Japanese Patent No. 2707341 (Patent Document 2) Formaldehyde, which is said to be one of the causative substances of sick house syndrome at the time of resin production and is currently listed as a target substance in the Air Pollution Control Law, is used in large quantities. Therefore, there is a problem that unreacted substances during production are occluded in the resin, and formaldehyde is generated in the process of thermal crosslinking after the formation of the intermediate layer of the photoreceptor. In order to prevent the release of the generated formaldehyde into the atmosphere, a recovery facility is necessary, and it is obviously expensive to introduce the facility.

In addition, for example, in the urethane resin disclosed in Japanese Patent No. 2790380 (Patent Document 3), an active hydrogen-containing group such as a polyol compound and an isocyanate group of an isocyanate compound that is a curing agent have a three-dimensional network cross-linking reaction. No formaldehyde is generated since a cured film is formed. However, since the reactivity of the isocyanate group is very high, there is a problem that the pot life of the coating liquid using these is very short.
Therefore, a method using a blocked isocyanate compound in which an isocyanate group is protected with a blocking agent such as oxime has been reported, and the pot life of a coating liquid using an organic solvent has been considerably improved (for example, JP-A-2005-115351). Publication (refer patent document 4).

Japanese Patent No. 3657138 Japanese Patent No. 2707341 Japanese Patent No. 2790380 JP 2005-115351 A

In order to form an intermediate layer composed of a thermosetting resin film on a conductive support as in the prior art, the coating film obtained after applying the intermediate layer coating liquid on the conductive support Is heat-cured, that is, a heat treatment for causing a crosslinking reaction is necessary.
Conventionally, in the production of a photoreceptor, the above heat treatment is performed after application of the intermediate layer coating solution. Thereafter, a photosensitive layer coating solution is applied onto the intermediate layer formed by thermosetting, and the resulting coating film is dried to obtain a photosensitive layer.

That is, in the formation of each layer in the production of the photoreceptor, at least two heat treatments are required, and reduction of energy consumption and shortening of the production process are required.
Immediately after coating the intermediate layer, a heating and drying step is performed to form a cured intermediate layer. After that, a photosensitive layer is applied onto the cured intermediate layer, and then a final heat drying is performed to prepare a photoconductor. That is, the heat drying step is performed at least twice, once after the intermediate layer is applied and once after the photosensitive layer is applied.

Then, after applying the intermediate layer coating liquid containing the conventional organic solvent as described in Patent Document 3 to form the precursor film of the intermediate layer, the organic solvent is removed without performing the thermosetting treatment. When the photosensitive layer coating solution is applied, the intermediate layer precursor film is affected by the organic solvent of the photosensitive layer coating solution, that is, a part of the intermediate layer precursor film is in the photosensitive layer coating solution. The problem of melting out arises. As a result, the constituent material of the intermediate layer and the photosensitive layer cross each other as impurities, so that their stable performance cannot be maintained, and the performance of the photosensitive member is lowered.
Moreover, the above problems become conspicuous when a laminated structure is formed by repeating coating as in a function-separated type photoreceptor.

  The present invention aims to reduce the environmental load and improve the production stability in the photoreceptor manufacturing process, has little sensitivity fluctuation due to the environment, exhibits high responsiveness even in a low temperature and low humidity environment, is small and has a high image forming speed. A highly reliable electrophotographic photoreceptor that can provide high-quality images even in low-temperature and low-humidity environments, reducing the total energy consumed, that is, reducing the environmental burden, reducing the number of processes and manufacturing time. The issue is to provide.

  Therefore, the present inventors have reacted with a blocked isocyanate compound and an isocyanate group in order to realize an intermediate layer coating solution using water as a solvent, which does not generate a volatile organic compound (VOC) and does not cause fire. An intermediate layer coating solution containing a resin having an active hydrogen-containing group and an aqueous medium is found, and if such an intermediate layer coating solution is used, a curing treatment is performed after application of the intermediate layer coating solution. That is, without performing a heat drying process that requires a large amount of heat energy and time, a photosensitive layer coating process is performed after natural drying for several minutes, and then a final heat drying process is performed, thereby drying the final photosensitive layer. And intermediate layer curing treatment (thermosetting cross-linking reaction) can be performed at the same time, and the performance equivalent to that obtained by heat drying immediately after the intermediate layer coating is obtained, and the present invention is completed. It was.

Thus, according to the present invention,
(A) On the conductive support, an intermediate layer coating solution containing a blocked isocyanate compound, a resin having an active hydrogen-containing group capable of reacting with an isocyanate group in the blocked isocyanate compound, and an aqueous medium is applied. The step of forming the intermediate layer precursor film by subjecting the obtained coating film to a drying treatment under conditions where the resin is not cured;
(B) On the precursor film of the intermediate layer, a step of applying a photosensitive layer coating solution using an organic solvent as a medium to form a precursor film of the photosensitive layer;
(C) The intermediate layer precursor film and the photosensitive layer precursor film are simultaneously heat-treated to cure the intermediate layer precursor film with resin and to dry the photosensitive layer precursor film. And a process for producing a photosensitive layer.

  According to the present invention, with the aim of reducing the environmental load and improving the production stability in the photoreceptor manufacturing process, there is little fluctuation in sensitivity due to the environment, high responsiveness even in a low-temperature and low-humidity environment, small size, and image forming speed. Fast and reliable electrophotographic photoreceptor that can provide high-quality images even in low-temperature and low-humidity environments, reducing the total energy consumption, that is, the environmental load, reducing the number of processes and manufacturing time Can be provided.

Moreover, the intermediate layer coating solution used is an aqueous medium as a solvent, which not only eliminates the problem of air pollution due to VOC in the production process, but also CO ₂ such as a petroleum-based solvent that has been conventionally used. Since there is no problem of discharge, it contributes to the prevention of global warming, and furthermore, there is no risk of fire, so the manufacturing system can be simplified and the manufacturing cost can be reduced.

  When an aqueous medium is used as the solvent for the intermediate layer coating solution, a resin having a high affinity for water must be used, and it has an intermediate layer formed using such an intermediate layer coating solution. The photoreceptor is inferior in moisture resistance. However, in the present invention, the resin is thermally cured with an isocyanate compound, the hydrophilic functional groups in the resin are reduced, and the coating film is densified as a cured film, so that the moisture resistance of the photoreceptor is improved and excellent. Environmental stability can be obtained.

The isocyanate group of the isocyanate compound reacts easily with water. However, in the present invention, since a blocked isocyanate compound in which an isocyanate group is protected with a stable protective group in water is used, a pot life equivalent to or higher than that of a conventional organic solvent-based coating liquid can be realized.
Further, by using a resin having an active hydrogen-containing group capable of reacting with an isocyanate group such as a hydroxyl group or an amide group, the resin can be easily thermoset with an isocyanate compound.
Furthermore, in the present invention, a dense cured film is formed by the presence of the isocyanate group in the blocked isocyanate compound at a molar ratio of 0.5 to 1.5 with respect to the active hydrogen-containing group in the resin. And excellent environmental characteristics as a photoreceptor.

  In addition, by including inorganic oxide fine particles such as titanium oxide and zinc oxide in the intermediate layer coating liquid of the present invention, the electrical resistance of the intermediate layer when used as a photoreceptor can be easily controlled, and the repetition characteristics Can prevent image defects such as black spots

FIG. 3 is a schematic cross-sectional view illustrating a configuration of a main part of a photoreceptor obtained by the manufacturing method of the present invention. FIG. 3 is a schematic cross-sectional view illustrating a configuration of a main part of a photoreceptor obtained by the manufacturing method of the present invention. FIG. 3 is a schematic cross-sectional view illustrating a configuration of a main part of a photoreceptor obtained by the manufacturing method of the present invention. 1 is a schematic side view showing a configuration of an image forming apparatus provided with a photoreceptor obtained by the production method of the present invention.

The method for producing the photoreceptor of the present invention includes:
(A) On the conductive support, an intermediate layer coating solution containing a blocked isocyanate compound, a resin having an active hydrogen-containing group capable of reacting with an isocyanate group in the blocked isocyanate compound, and an aqueous medium is applied. The step of forming the intermediate layer precursor film by subjecting the obtained coating film to a drying treatment under conditions where the resin is not cured;
(B) On the precursor film of the intermediate layer, a step of applying a photosensitive layer coating solution using an organic solvent as a medium to form a precursor film of the photosensitive layer;
(C) The intermediate layer precursor film and the photosensitive layer precursor film are simultaneously heat-treated to cure the intermediate layer precursor film with resin and to dry the photosensitive layer precursor film. And a step of obtaining a photosensitive layer.

1 to 3 are schematic cross-sectional views showing the configuration of the main part of a photoreceptor (hereinafter also referred to as “the photoreceptor of the present invention”) obtained by the production method of the present invention.
FIG. 1 shows the structure of the main part of a laminated photoreceptor in which the photosensitive layer is a laminated photosensitive layer in which a charge generation layer and a charge transport layer are laminated in this order (also referred to as “function-separated photosensitive layer”). It is a schematic cross section.
FIG. 2 is a schematic cross-sectional view showing the configuration of the main part of a laminated photoreceptor, which is an inverted two-layer laminated photosensitive layer in which a charge transport layer and a charge generation layer are laminated in this order.
FIG. 3 is a schematic cross-sectional view showing the configuration of the main part of a single-layer type photoreceptor that is a single-layer type photosensitive layer having a single photosensitive layer.
1 and 2 may be any, but the multilayer photosensitive layer of FIG. 1 is preferred.

In the photoreceptor of FIG. 1, an intermediate layer 2, a charge generation layer 3 containing a charge generation material, and a charge transport layer 4 containing a charge transport material are laminated in this order on the surface of a conductive support 1. The laminated photosensitive layer 5 is formed in this order.
In the photoreceptor of FIG. 2, an intermediate layer 2, a charge transport layer 4 containing a charge transport material, and a charge generation layer 3 containing a charge generation material are laminated in this order on the surface of the conductive support 1. The reverse two-layer type laminated photosensitive layer 5 is formed in this order.
In the photoreceptor of FIG. 3, an intermediate layer 2, a single-layer type photosensitive layer 5 ′ containing a charge generation material and a charge transport material are formed in this order on the surface of the conductive support 1.
Hereinafter, the above steps will be sequentially described.

[Step (A)]
In the step (A), first, an intermediate layer coating solution is applied onto the conductive support.

The intermediate layer (also referred to as “undercoat layer”) 2 has a function of preventing charge injection from the conductive support to the single-layer type photosensitive layer or the laminated type photosensitive layer. That is, the decrease in chargeability of the single-layer type photosensitive layer or the multilayer type photosensitive layer is suppressed, the decrease in surface charge other than the portion to be erased by exposure is suppressed, and the occurrence of image defects such as fog is prevented. In particular, during image formation by the reversal development process, it is possible to prevent the occurrence of image fogging called black spots in which minute black dots made of toner are formed on a white background portion.
In addition, the intermediate layer covering the surface of the conductive support reduces the degree of unevenness, which is a defect on the surface of the conductive support, makes the surface uniform, and forms a single layer type photosensitive layer or a multilayer type photosensitive layer. And the adhesion (adhesiveness) between the conductive support and the single-layer type photosensitive layer or the multilayer type photosensitive layer can be improved.

(Intermediate layer coating solution)
The intermediate layer coating solution used in the method for producing a photoreceptor of the present invention comprises a blocked isocyanate compound, a resin having an active hydrogen-containing group capable of reacting with an isocyanate group in the blocked isocyanate compound, and an aqueous medium. Including.

(Block isocyanate compound)
A blocked isocyanate compound is a compound in which an isocyanate group of an aqueous isocyanate compound that can be dissolved or dispersed in water is protected with a blocking agent such as oxime, and contains active hydrogen that can react with an isocyanate group such as a hydroxyl group or an amide group by heating. An addition reaction is initiated with the resin having a group, the blocking agent is removed, and the crosslinking reaction proceeds. That is, the blocked isocyanate compound becomes a resin crosslinking agent.

  The aqueous isocyanate compound is a form in which an organic polyisocyanate having a plurality of isocyanate groups in one molecule is modified with various hydrophilic groups such as polyethylene oxide, a carboxyl group or a sulfonic acid group, or dissolved or made into a self-emulsifying type, or It is a compound in a form that is forcibly emulsified with a surfactant or the like so as to be dispersible in water.

Examples of the organic polyisocyanate include phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, naphthylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, hydrogenated diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, hydrogenated toluene diisocyanate. Tetramethylene xylylene diisocyanate; and biuret, uretdione, carbodiimide, isocyanurate, and uretonimine modifications of the isocyanate. These organic polyisocyanates can be used alone or in combination of two or more.
Among these organic polyisocyanates, aliphatic diisocyanate-based organic polyisocyanates such as hexamethylene diisocyanate and isophorone diisocyanate tend to have an affinity for water, so that they can be easily dissolved and dispersed in water and have a crosslinking density. It is particularly preferable because it is easy to increase the value.

In addition, various prepolymers derived from organic polyisocyanates, and further as blocking agents for blocking isocyanate groups in these organic polyisocyanates include active methylene compounds such as ethyl acetate and acetylacetone; butyl mercaptan , Mercaptan compounds such as dodecyl mercaptan, acid amide compounds such as acetanilide and acetic acid amide; lactam compounds such as ε-caprolactam, δ-valerolactam and γ-butyrolactam; acid imides such as succinimide and maleic acid imide Compounds: Imidazole compounds such as imidazole and 2-methylimidazole; Urea compounds such as urea, thiourea and ethyleneurea; Formamide oxime, acetoaldoxime, acetone oxime, methyl ethyl keto Oxime compounds such as shim, methyl isobutyl ketoxime, cyclohexanone oxime; amine compounds such as diphenylaniline, aniline, carbazole, ethyleneimine, polyethyleneimine, etc. These blocking agents may be used alone or in combination of two or more. Can be used in combination.
Among these blocking agents, oxime compounds such as methyl ethyl ketoxime and lactam compounds such as ε-caprolactam are particularly preferable from the viewpoint of versatility, ease of production, and workability.

Further, since the isocyanate group easily reacts with water, it is preferable to use a blocking agent having a dissociation temperature of 110 ° C. or higher so that the blocking agent dissociates after the water in the coating film volatilizes.
Therefore, the block isocyanate compound preferably has a structure in which hexamethylene diisocyanate or isophorone diisocyanate is blocked with an oxime or lactam blocking agent.

As the blocked isocyanate compound, for example,
Manufactured by Sumika Bayer Urethane Co., Ltd., product names: Bihijoule BL5140, BL5235 and VPLS2310;
Product name: Takenate WB-700, WB-820 and WB-920, manufactured by Mitsui Chemicals Polyurethane Co., Ltd .;
Nippon Polyurethane Industry Co., Ltd., developed product name: BWD-102
Asahi Kasei Chemicals Corporation, developed product name: X1238, X1248 and X1258
Etc.

(resin)
The active hydrogen-containing group in the resin having an active hydrogen-containing group that can react with the isocyanate group in the blocked isocyanate compound is preferably a hydroxyl group or an amide group that can react with the isocyanate group in a high yield.

That is, a polyol resin or polyamide having a hydroxyl group or an amide group to form a crosslinked structure with a blocked isocyanate as a curing agent (in the case of having only one functional group, it does not have a crosslinked structure but has a high molecular weight). Resins are preferred. Further, by controlling the structure of these polyol resins, polyamide resins, satisfactorily can be dispersed and dissolved in water, further these resins have high adhesion to the substrate, with the substrate when the photosensitive member Image defects due to poor contact can also be effectively prevented.

As these polyol resin and polyamide resin, for example,
Product name: AQD-457 and AQD-473, Asahi Glass Co., Ltd., product name: Exenol 420 and 720, Sanyo Chemical Industries, Ltd., product name: Sannix GP-400, GP-700 And polyether polyol resins such as SP-750;
Hitachi Chemical Co., Ltd., product name: Phthalkid W2343, DIC Corporation, product name: Watersol S-118, CD-520 and BCD-3040, Harima Kasei Co., Ltd., product name: Hallidip WH-1188, etc. Polyester polyol resins of
Product name: Burnock WE-300, WE-304 and WE-306, manufactured by Asia Industry Co., Ltd., product name: WAP-473-FD and WAP-548, manufactured by DIC Corporation;

Manufactured by Kuraray Co., Ltd., product name: polyvinyl alcohol resins such as modified polyvinyl alcohols such as Kuraray Poval PVA-203 and PVA-205;
Manufactured by Sekisui Chemical Co., Ltd., product name: polyvinyl acetal resins such as ESREC K KW-1 and KW-3;
Manufactured by Shin-Etsu Chemical Co., Ltd., product name: cellulose such as water-soluble cellulose ethers such as Metroles 65SH-50 and 65SH-400;
Made by Nagase ChemteX Corporation, product name: Water-soluble nylon (polyamide compound resin) such as Toresin FS-350 and FS-500
Etc.

The isocyanate group of the blocked isocyanate compound is preferably present in the blocked isocyanate compound in a molar ratio of 0.5 to 1.5 with respect to the active hydrogen-containing group of the resin, more preferably 0.5 to 1.2. Preferably, it is 0.6 or more and 1.1 or less.
When the molar ratio (H / B) is less than 0.5 or exceeds 1.5, a large number of unreacted functional groups remain, the crosslinking density is lowered, and the photosensitive layer having the formed intermediate layer is formed. The environmental stability of the body may be reduced.

(Inorganic oxide fine particles)
The intermediate layer coating solution of the present invention may further contain inorganic oxide fine particles.
The inorganic oxide fine particles adjust the volume resistance value of the intermediate layer when it is used as a photoconductor to prevent the injection of carriers from the conductive support to the photoconductive layer, and to improve the electric characteristics of the photoconductor in various environments. It has a function to maintain.
Examples of the inorganic oxide fine particles include fine particles such as titanium oxide, aluminum oxide, tin oxide, zinc oxide, antimony oxide, silicon oxide, indium oxide, zirconium oxide, magnesium oxide, and barium sulfate. From the viewpoint of dispersibility, fine particles of titanium oxide, zinc oxide and aluminum oxide are preferred, and fine particles of titanium oxide and zinc oxide are particularly preferred.

The shape of the inorganic oxide fine particles may be any of dendritic, acicular and granular.
The average primary particle size of the inorganic oxide fine particles is preferably about 20 to 500 nm.

As inorganic oxide fine particles, for example,
Ishihara Sangyo Co., Ltd., product name: TTO-55D (shape: granular, average primary particle size: 30-50 nm), TTO-D-1 (shape: dendritic, average primary particle size: minor axis 40-70 nm, long (Axis: 200 to 300 nm), ST-21 (shape: granular, average primary particle size (measured by X-ray): 70 nm), PT-401M (shape: granular, average primary particle size: 70 nm) and CR-EL (shape: Granular, average primary particle size: 250 nm),
Product name: GTR100 (shape: granular, average primary particle size: 260 nm), manufactured by Sakai Chemical Industry Co., Ltd.
Product name: MT-500SAS (shape: granular, average primary particle size: 35 nm) and JR-603 (shape: granular, average primary particle size: 280 nm)
Fine particles of titanium oxide such as

Ishihara Sangyo Co., Ltd., product name: FZO-50 (shape: granular, average primary particle size: 21 nm),
Product name: FINEX30 (shape: granular, average primary particle size: 35 nm), manufactured by Sakai Chemical Industry Co., Ltd.
Product name: MZ-300 (shape: granular, average primary particle size: 30-40 nm)
Product name: F-2 (shape: rod-shaped, average primary particle size: 65 nm), manufactured by Hakusui Tech Co., Ltd.
And zinc oxide fine particles.

The inorganic oxide fine particles (P) are preferably in a weight ratio (P / R) in the range of 1/1 to 9/1 with respect to the crosslinked resin (total of blocked isocyanate compound and resin: R).
When this weight ratio (P / R) is less than 1/1, the characteristics of the intermediate layer depend on the characteristics of the crosslinked resin, and there is a possibility that the characteristics of the photoconductor may change greatly when the temperature and humidity are changed and used repeatedly. On the other hand, when the weight ratio (P / R) exceeds 9/1, the dispersibility of the inorganic oxide fine particles is lowered, and the possibility of forming an aggregate is increased, and the adhesiveness to the conductive support is lowered. As a result, image defects such as black spots may occur.

(Other additives)
The intermediate layer coating solution of the present invention may further contain an antifoaming agent.
The antifoaming agent is intended to suppress foam by adding a very small amount to the intermediate layer coating solution.
When water is used as a solvent as in the intermediate layer coating solution of the present invention, and particularly when a water-soluble resin is added, it is foamed by dispersion or stirring during preparation, and only the dispersion and stirring efficiency is lowered. Instead, it may foam during application and cause coating film defects. Antifoaming agents suppress these problems.

Examples of the antifoaming agent include a silicone system, a surfactant system, a polyether system, a higher alcohol system, an emulsion system, and an oil compound system. Among these, an oil compound system containing silica powder having a strong foam breaking property is particularly preferable.
Examples of antifoaming agents are San Nopco Corporation, product names: SN deformers 444, 470, 485, PC (polyether type), SN deformers 1311, 1316 (silicone type), SN deformers 777, 328, 480, H. -2 (oil compound system), manufactured by Nissho Sangyo Co., Ltd., product name: TSA750 (oil compound system), TSA770 (emulsion system), manufactured by Toray Dow Corning Co., Ltd .: product name: silicone such as DK Q1-1247 -Emulsions are listed.

The antifoaming agent is preferably 0.05 to 0.0005 parts by weight with respect to 1 part by weight of the crosslinked resin (total of blocked isocyanate compound and resin: R).
If the defoamer exceeds 0.05 parts by weight, the electrical characteristics of the photoreceptor may be deteriorated, and if it is less than 0.0005 parts by weight, an effective foam breaking effect may not be obtained.

  The intermediate layer coating solution of the present invention may contain additives such as a viscoelasticity adjusting agent, preservative, and curing catalyst as long as the effects of the present invention are not impaired.

  As the viscoelasticity modifier, for example, manufactured by San Nopco Corporation, product names: SN thickener 601, A816 (polyether type), SN thickener 607 (urethane modified polyether type), SN thickener 617 (modified polyacrylic acid type), A product name: Water-soluble cellulose ether such as Metroze 65SH-4000 manufactured by Shin-Etsu Chemical Co., Ltd. can be mentioned.

  As an antiseptic | preservative, the organic nitrogen sulfur type compound like the product made from San Nopco Co., Ltd. product name: Nopcoside SN-135W etc. are mentioned, for example.

  Examples of the curing catalyst include amine compounds such as triethylamine, diethylethanolamine, and hexamethylenediamine; and organotin compounds such as dibutyltin dilaurate and dioctyltin dilaurate.

In addition, the intermediate layer coating solution of the present invention may contain an electron transporting material in order to adjust conductivity.
Examples of the electron transport material include perylene dyes, quinones such as diphenoquinone and naphthoquinone derivatives, cyano compounds such as tetracyanoethylene and terephthalmalondinitrile, aldehydes such as 4-nitrobenzaldehyde, anthraquinone and alizarin. Anthraquinones are mentioned.

The intermediate layer coating solution of the present invention can be prepared by dissolving or dispersing a blocked isocyanate compound, a resin having two or more active hydrogen-containing groups capable of reacting with an isocyanate group, and an optional additive in an aqueous medium. it can.
The aqueous medium means water or a mixed medium of water and a hydrophilic organic solvent such as a lower alcohol. In the present invention, only water is preferable.

  In order to disperse the components of the intermediate layer coating liquid, especially inorganic oxide fine particles, in water, common dispersers such as paint shakers, ball mills, sand mills, ball mills, sand mills, attritors, vibration mills, ultrasonic dispersers A general grinder such as may be used.

In order to stabilize this dispersion, a dispersion stabilizer may be added to the intermediate layer coating solution.
Examples of the dispersion stabilizer include Sanyo Kasei Co., Ltd., product names: Caribon L-400, Elestat AP-130, Sunspear PS-8, PDN-173, Ionette S-85, New Pole PE-61, and San Nopco shares. Product name: Roma PWA-40, Nobco Santo RFA, SN Dispersant 2060, 5020, 5029, 5468, 7347C and SN Wet P, manufactured by Nissin Chemical Industry Co., Ltd., product names: Surfinol 104E and Olphin PD-003 Product name: Poise 520, 530, Homogenol L 100, Daiichi Kogyo Seiyaku Co., Ltd., Charoru AN-103P, AH-144P, Discoat N-14, Toho Chemical Industries Co., Ltd., product name : Dibrozine A-100, Neoscope 30 And so on.

(Conductive support 1)
The conductive support on which the intermediate layer coating solution is applied serves as an electrode for the photoreceptor and also functions as a support member for each of the other layers.
The constituent material of the conductive support is not particularly limited as long as it is a material used in this field.
Specifically, metals and alloy materials such as aluminum, aluminum alloy, copper, brass, zinc, nickel, stainless steel, chromium, molybdenum, vanadium, indium, titanium, gold, platinum: polyethylene terephthalate, polyamide, polyester, polyoxy Polymer material such as methylene, polystyrene, cellulose, polylactic acid, hard paper, glass substrate laminated with metal foil, metal material or alloy material deposited, conductive polymer, tin oxide, oxidation Examples thereof include those obtained by depositing or applying a layer of a conductive compound such as indium or carbon black.

Examples of the shape of the conductive support include a sheet shape, a cylindrical shape, a columnar shape, and an endless belt (seamless belt) shape.
If necessary, the surface of the conductive support is subjected to irregular reflection treatment such as anodizing film treatment, surface treatment with chemicals, hot water, coloring treatment, and surface roughening within a range that does not affect the image quality. May be given.

  The irregular reflection treatment is particularly effective when the photoreceptor according to the present invention is used in an electrophotographic process using a laser as an exposure light source. That is, in the electrophotographic process using a laser as an exposure light source, the wavelength of the laser beam is uniform, so the laser beam reflected on the surface of the photoconductor and the laser beam reflected inside the photoconductor cause interference, Interference fringes due to this interference may appear in the image and cause image defects. Therefore, by performing irregular reflection processing on the surface of the conductive support, it is possible to prevent image defects due to interference of laser light having a uniform wavelength.

(Application)
In the case of a sheet, the application method of the intermediate layer coating solution is the Baker applicator method, the bar coater method (for example, the wire bar coater method), the casting method, the spin coating method, the roll method, the blade method, the bead method, and the curtain method. In the case of a drum, a spray method, a vertical ring method, a dip coating method, etc. are mentioned.
As an application method, an optimum method may be selected in consideration of physical properties and productivity of the coating liquid, and an immersion method, a blade coater method, and a spray method are particularly preferable.

  The dip coating method is a method of forming a layer on the conductive support 1 by immersing the conductive support 1 in a coating tank filled with a coating solution and then pulling it up at a constant speed or a speed that changes sequentially. is there. Since this method is relatively simple and excellent in terms of productivity and cost, it is widely used for manufacturing a photoreceptor. In addition, in order to stabilize the dispersibility of a coating liquid, you may provide the coating liquid dispersion | distribution apparatus represented by the ultrasonic generator in the apparatus used for a dip coating method.

(Drying process)
In the step (A), the resulting coating film is then dried under conditions where the resin is not cured to form an intermediate layer precursor film.
“Drying” in the present invention corresponds to “finger touch drying” in JIS K5500 (painting term), “when the fingertip is not soiled with the sample by touching the center of the painted surface”.

Although the drying treatment depends on the constituent material and the film thickness of the coating film, the coating film without heating is not cured by the resin, for example, the coating film is at room temperature and normal pressure for 1 to 30 minutes (preferably 1 to 15 minutes). It is preferable to hold.
Here, “normal temperature” means about 5 to 35 ° C., and “normal pressure” means about 1 atm (1.01325 × 10 ⁵ Pa).
The humidity may be about 80% or less in terms of relative humidity.
As conditions for the drying treatment, a temperature of about 20 to 30 ° C., a relative humidity of 60% or less, and a pressure of about 1 atm are preferable.

The thickness of the intermediate layer is preferably from 0.1 to 5 μm, particularly preferably from 0.5 to 5 μm.
When the film thickness of the intermediate layer is less than 0.1 μm, the film substantially does not function as the intermediate layer, and the surface of the carrier from the conductive support cannot be obtained by covering defects of the conductive support. The injection cannot be prevented, and the chargeability may be lowered.
On the other hand, when the film thickness of the intermediate layer exceeds 5 μm, the coating film is not sufficiently dried, and the characteristics of the photoreceptor may be deteriorated. That is, when the photosensitive layer coating solution is applied onto an intermediate layer precursor film that is insufficiently dried, uneven coating may occur, which may cause partial image defects. Further, in the final heat treatment, excess water confined in the intermediate layer may be vaporized to generate bubbles in the photosensitive layer, or the bubbles may destroy the layer. In order to prevent this, the coating film may be sufficiently dried. However, natural drying takes time, and heat drying is necessary to shorten the time.

[Step (B)]
In the step (B), the precursor film of the photosensitive layer is formed by applying a coating solution for the photosensitive layer using an organic solvent as a medium on the precursor film of the intermediate layer formed in the step (A).
Step (B) depends on the form of the photosensitive layer. Specifically, the charge generation layer coating solution containing the charge generation material and the charge transport layer coating solution containing the charge transport material are added in this order or in reverse order. Coating the intermediate layer precursor film to form a laminated photosensitive layer precursor film, or a single-layer photosensitive layer coating solution containing a charge generating substance and a charge transporting substance. It is preferably a step of forming a single layer type photosensitive layer precursor film by coating on the intermediate layer precursor film.
Hereinafter, the configuration of the coating liquid for each layer and the coating method will be described.

(Multilayer type photosensitive layer 5)
The laminated photosensitive layer 5 includes a charge generation layer 3 and a charge transport layer 4. As described above, by assigning the charge generation function and the charge transport function to separate layers, the optimum material constituting each layer can be independently selected.
In the following description, a stacked photosensitive layer (FIG. 1) in which a charge generation layer and a charge transport layer are stacked in this order will be described. In the case of an inverted two-layer stacked photosensitive layer (FIG. 2), It is basically the same except that the stacking order is different.

(Charge generation layer 3)
The charge generation layer is mainly composed of a charge generation material having a charge generation capability of generating charges by absorbing irradiated light, and optionally contains a known additive and a binder resin (binder).
As the charge generation material, a compound used in this field can be used.
Specifically, an azo pigment (having a carbazole skeleton, a styryl stilbene skeleton, a triphenylamine skeleton, a dibenzothiophene skeleton, an oxadiazole skeleton, a fluorenone skeleton, a bis-stilbene skeleton, a distyryl oxadiazole skeleton, or a distyryl carbazole skeleton. , Monoazo pigments, bisazo pigments, trisazo pigments, etc.), perylene pigments (peryleneimide, perylene acid anhydride, etc.), polycyclic quinone pigments (quinacridone, anthraquinone, pyrenequinone, etc.), phthalocyanine pigments (metal phthalocyanine, no Metal phthalocyanine, halogenated metal-free phthalocyanine, etc.), indigo pigments (indigo, thioindigo, etc.), squarylium dyes, azurenium dyes, thiopyrylium dyes, pyrylium salts, triphenylmethane Organic pigments or dyes such as dyes, further selenium, inorganic materials such as amorphous silicon. These charge generating materials can be used alone or in combination of two or more.
Among these charge generation materials, phthalocyanine pigments, azo pigments, and perylene pigments are particularly preferable because of their high sensitivity.

  The charge generation layer is a chemical sensitizer, an optical sensitizer, an antioxidant, an ultraviolet absorber, a dispersion stabilizer, a sensitizer, a leveling agent, a plasticizer, as long as the preferable characteristics of the present invention are not impaired. An appropriate amount of one or more known additives selected from fine particles of inorganic compounds or organic compounds may be contained. These additives may be contained in the charge transport layer described later, or may be contained in both the charge generation layer and the charge transport layer.

The chemical sensitizer and the optical sensitizer improve the sensitivity of the photoreceptor, suppress an increase in residual potential and fatigue due to repeated use, and improve electrical durability.
Examples of chemical sensitizers include acid anhydrides such as succinic anhydride, maleic anhydride, phthalic anhydride, and 4-chloronaphthalic anhydride; cyano compounds such as tetracyanoethylene and terephthalmalondinitrile, 4-nitrobenzaldehyde, and the like. Aldehydes; anthraquinones such as anthraquinone and 1-nitroanthraquinone; polycyclic or heterocyclic nitro compounds such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitrofluorenone; diphenoquinone compounds Examples thereof include electron-withdrawing materials and those obtained by polymerizing these electron-withdrawing materials.

  Examples of optical sensitizers include xanthene dyes, quinoline pigments, organic photoconductive compounds such as copper phthalocyanine, triphenylmethane dyes typified by methyl violet, crystal violet, knight blue and victoria blue; erythrosin, Acridine dyes typified by rhodamine B, rhodamine 3R, acridine orange and frappeocin; thiazine dyes typified by methylene blue and methylene green; oxazine dyes typified by capri blue and meldra blue; cyanine dyes; styryl dyes; Examples include pyrylium salt dyes and thiopyrylium salt dyes.

Antioxidants can maintain sensitivity stability over a long period of time.
Antioxidants include phenolic antioxidants such as hindered phenols such as 2,6-di-t-butyl-4-methylphenol (2,6-di-t-butyl-p-cresol: BHT). , Amine antioxidants such as hindered amines, vitamin E, hydroquinone, paraphenylenediamine, arylalkanes and derivatives thereof, organic sulfur compounds, organic phosphorus compounds, etc., and these may be used alone or in combination of two or more. Can be used.

The addition amount of the antioxidant is preferably from 0.1 to 40 parts by weight, particularly preferably from 0.5 to 15 parts by weight, based on 100 parts by weight of the charge generation material.
If the addition amount of the antioxidant is less than 0.1 parts by weight, there is a possibility that sufficient effects cannot be obtained for improving the stability of the coating solution and improving the durability of the photoreceptor. On the other hand, if the amount of the antioxidant added exceeds 40 parts by weight, the photoreceptor characteristics may be adversely affected.

Leveling agents and plasticizers can improve film formability, flexibility and surface smoothness.
Examples of the leveling agent include a silicone leveling agent.
Examples of the plasticizer include dibasic acid esters such as phthalate esters, fatty acid esters, phosphate esters, chlorinated paraffins, and epoxy type plasticizers.

  Fine particles of an inorganic compound or an organic compound can enhance mechanical strength and improve electrical characteristics. Examples of such fine particles include fine particles exemplified in an intermediate layer described later.

The charge generation layer can be formed by a known dry method and wet method.
Examples of the dry method include a method of vacuum-depositing a charge generating material on the surface of a conductive support.
As a wet method, for example, a charge generation material, and if necessary, an additive and a binder resin are dissolved or dispersed in an appropriate organic solvent to prepare a charge generation layer coating solution, and this coating solution is electrically conductively supported. The method of apply | coating to the intermediate | middle layer surface formed on the body, and then drying and removing an organic solvent is mentioned.

The binder resin can improve the mechanical strength and durability of the charge generation layer, the binding property between layers, and the like, and a resin having a binding property used in this field can be used.
Specifically, vinyl resins such as polymethyl methacrylate, polystyrene, polyvinyl chloride, polycarbonate, polyester, polyester carbonate, polysulfone, polyarylate, polyamide, methacrylic resin, acrylic resin, polyether, polyacrylamide, polyphenylene oxide, etc. Thermoplastic resin: Thermosetting resin such as phenoxy resin, epoxy resin, silicone resin, polyurethane, phenol resin, alkyd resin, melamine resin, phenoxy resin, polyvinyl butyral, polyvinyl formal, partially cross-linked products of these resins, these resins Copolymer resins containing two or more of the structural units contained in (vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, acrylo Tolyl - insulating resin such as styrene copolymer resin). These binder resins can be used alone or in combination of two or more.

The mixing ratio of the charge generation material and the binder resin is not particularly limited, but the charge generation material is usually about 10 to 99% by weight.
If the charge generation material is less than 10% by weight, the sensitivity of the photoreceptor may be lowered.
On the other hand, when the charge generation material exceeds 99% by weight, not only the film strength of the charge generation layer decreases, but also the dispersibility of the charge generation material decreases and coarse particles may increase. For this reason, surface charges other than the portion to be erased by exposure are reduced, and there is a risk that image defects, particularly an image called black spots where toner adheres to a white background and minute black spots are formed, increase.

  Examples of the organic solvent include aromatic hydrocarbons such as toluene, xylene, mesitylene, tetralin, diphenylmethane, dimethoxybenzene, and dichlorobenzene; halogenated hydrocarbons such as dichloromethane, dichloroethane, and tetrachloropropane; tetrahydrofuran (THF) and dioxane. , Ethers such as dibenzyl ether, dimethoxymethyl ether and 1,2-dimethoxyethane; ketones such as methyl ethyl ketone, cyclohexanone, acetophenone and isophorone; esters such as methyl benzoate, ethyl acetate and butyl acetate, and diphenyl sulfide Sulfur-containing solvents; Fluorine solvents such as hexafluoroisopropanol; aprotic polar solvents such as N, N-dimethylformamide and N, N-dimethylacetamide Etc., and these may be used alone or as a mixed solvent. A mixed solvent obtained by adding alcohols, acetonitrile, or methyl ethyl ketone to such a solvent can also be used. Among these solvents, non-halogen organic solvents are preferably used in consideration of the global environment.

Prior to dissolving or dispersing the constituent materials in the resin solution, the charge generating material may be pre-ground.
The preliminary pulverization can be performed using, for example, a general pulverizer such as a ball mill, a sand mill, an attritor, a vibration mill, or an ultrasonic disperser.
The dissolution or dispersion of the constituent materials in the resin solution can be performed using, for example, a general disperser such as a paint shaker, a ball mill, or a sand mill. At this time, it is preferable to appropriately set the dispersion conditions so that impurities are generated from the members constituting the container and the disperser due to wear and the like and are not mixed into the coating liquid.

  The application method of the coating solution for the charge generation layer is a baker applicator method, a bar coater method, a casting method, a spin coating method, a roll method, a blade method or the like in the case of a sheet, and a spray method or a vertical ring method in the case of a drum. And a dip coating method.

The thickness of the charge generation layer is not particularly limited, but is preferably 0.05 to 5 μm, particularly preferably 0.1 to 1 μm.
When the thickness of the charge generation layer is less than 0.05 μm, the light absorption efficiency is lowered, and the sensitivity may be lowered. On the other hand, if the thickness of the charge generation layer exceeds 5 μm, charge transport within the charge generation layer becomes a rate-limiting step in the process of erasing the charge on the surface of the photoreceptor, and the sensitivity may be lowered.

(Charge transport layer 4)
The charge transport layer contains, as main components, a charge transport material having the ability to accept and transport charges generated by the charge generation material and a binder resin (binder).

As the charge transport material, a compound used in this field can be used.
Specifically, poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, oxadiazole derivatives Imidazole derivatives, 9- (p-diethylaminostyryl) anthracene, 1,1-bis (4-dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline, pyrazoline derivatives, phenylhydrazones, hydrazone derivatives, triphenylamine series Electron donating substances such as compounds, tetraphenyldiamine compounds, triphenylmethane compounds, stilbene compounds, azine compounds having a 3-methyl-2-benzothiazoline ring;

Fluorenone derivatives, dibenzothiophene derivatives, indenothiophene derivatives, phenanthrenequinone derivatives, indenopyridine derivatives, thioxanthone derivatives, benzo [c] cinnoline derivatives, phenazine oxide derivatives, tetracyanoethylene, tetracyanoquinodimethane, promanyl, chloranil And electron accepting substances such as benzoquinone. These charge transport materials can be used alone or in combination of two or more.

The ratio E / B between the weight E of the charge transport material and the weight B of the binder resin is 10/12 to 10/25, preferably 10/16 to 10/20.
When the ratio E / B is less than 10/25, the relative amount ratio of the binder resin to the charge transport material is increased, and sufficient sensitivity may not be obtained.

  On the other hand, if the ratio E / B exceeds 10/12, the printing durability of the charge transport layer and the durability of the photoreceptor may be lowered.

As the binder resin, one or more of the same binder resins as those contained in the charge generation layer can be used.
Among these resins, polycarbonate-based resins, polyarylate resins and polystyrene resins are photochemically stable, excellent in compatibility with charge transport materials, and have a volume resistance of 10 ¹³ Ω or more. It is preferable because it is excellent in electrical insulation and has excellent film forming properties and potential characteristics.

  The charge transport layer may contain an appropriate amount of the same additive as that contained in the charge generation layer, if necessary, within the range not impairing the effects of the present invention.

The charge transport layer is prepared by dissolving or dispersing a charge transport material, a binder resin and, if necessary, other additives in an appropriate organic solvent to prepare a charge transport layer coating solution. It can be formed by applying to the surface and then drying to remove the organic solvent. More specifically, for example, a charge transport layer coating solution is prepared by dissolving or dispersing a charge transport material and other additives as required in a resin solution obtained by dissolving a binder resin in an organic solvent. To do.
Other processes and conditions are in accordance with the formation of the charge generation layer.

Although the film thickness of a charge transport layer is not specifically limited, 10-60 micrometers is preferable and 10-40 micrometers is especially preferable.
If the thickness of the charge transport layer is less than 10 μm, the charge retention ability may be reduced. Conversely, if the thickness of the charge transport layer is more than 60 μm, sharpness decreases and residual potential increases, There is a risk that image deterioration will occur remarkably.

[Single layer type photosensitive layer 5 ']
The single-layer type photosensitive layer contains a charge generation material, a charge transport material, and a binder resin (binder) as main components.
The single-layer type photosensitive layer may contain an appropriate amount of the same additive as that contained in the charge generation layer, if necessary, within the range not impairing the effects of the present invention.

The single-layer type photosensitive layer is prepared by dissolving and / or dispersing a charge generating substance, a charge transporting substance and other additives as required in an appropriate organic solvent to prepare a single-layer type photosensitive layer coating solution. The coating liquid can be applied to the surface of the intermediate layer formed on the conductive support and then dried to remove the organic solvent.
Other processes and conditions are in accordance with the formation of the charge generation layer and the charge transport layer.

Although the film thickness of a single layer type photosensitive layer is not specifically limited, 10-100 micrometers is preferable and 15-50 micrometers is especially preferable.
If the film thickness of the single-layer type photosensitive layer is less than 10 μm, the charge holding ability on the surface of the photoreceptor may be lowered, and if the film thickness of the single-layer type photosensitive layer exceeds 100 μm, the productivity may be lowered. is there.

[Step (C)]
In the step (C), the intermediate layer precursor film formed in the step (A) and the photosensitive layer precursor film formed in the step (A) are simultaneously heat-treated, and the intermediate layer precursor film is formed. The resin is cured and the precursor film of the photosensitive layer is dried to obtain an intermediate layer and a photosensitive layer.

(Heat treatment)
Although the heat treatment depends on the constituent material and film thickness of each precursor film, the temperature of each precursor film is 110 to 150 ° C. (preferably 130 to 150 ° C.) and 15 to 90 minutes under normal pressure (preferably 30 to 30 ° C.). 60 minutes).
When the heat treatment temperature is 110 ° C. or lower, the intermediate layer blocking agent may not be dissociated and the curing reaction may not occur. On the other hand, when the heat treatment temperature exceeds 150 ° C., the obtained intermediate layer or photosensitive layer is deteriorated, the electrical characteristics at the time of repeated use are deteriorated, and the obtained image may be deteriorated.

Here, “normal pressure” means about 1 atm (1.01325 × 10 ⁵ Pa).
The heat treatment step can be performed using a known apparatus such as a hot air drying furnace or a far infrared drying furnace.

(Protective layer (not shown))
The photoreceptor of the present invention may have a protective layer (not shown) on the surface of the multilayer photosensitive layer 5 and the single-layer photosensitive layer 5 ′.
The protective layer has functions of improving the abrasion of the photosensitive layer and preventing chemical adverse effects caused by ozone, nitrogen oxides, and the like.

The protective layer is prepared by, for example, preparing a protective layer coating solution by dissolving or dispersing a binder resin in an appropriate organic solvent and, if necessary, an additive such as an antioxidant or an ultraviolet absorber. It can be formed by applying a working solution to the surface of a single-layer type photosensitive layer or a laminated type photosensitive layer, and removing the organic solvent by drying.
Other processes and conditions are in accordance with the formation of the photosensitive layer. That is, a protective layer coating film is formed on the photosensitive layer precursor film to form a protective layer precursor film, and the intermediate layer precursor film and the photosensitive layer precursor film are simultaneously heat-treated. .

The thickness of the protective layer is not particularly limited, but is preferably 0.5 to 10 μm, and particularly preferably 1 to 5 μm. When the protective layer thickness is less than 0.5 μm, the scratch resistance of the surface of the photoreceptor is inferior and durability is high. May be insufficient. On the other hand, if the thickness of the protective layer exceeds 10 μm, the resolution of the photoreceptor may be lowered.

  The photoconductor of the present invention includes, for example, a photoconductor, a charging unit for charging the photoconductor, an exposure unit for exposing the charged photoconductor to form an electrostatic latent image, and an electrostatic latent image. A developing unit that forms a toner image by developing; a transfer unit that transfers the toner image onto the recording material; a fixing unit that fixes the transferred toner image on the recording material to form an image; The present invention can be used in an image forming apparatus including at least a cleaning unit that removes and collects residual toner and a neutralizing unit that neutralizes surface charge remaining on the photosensitive member.

  FIG. 4 is a schematic side view showing the configuration of an image forming apparatus provided with a photoreceptor obtained by the manufacturing method of the present invention. The image forming apparatus will be described with reference to this drawing, but is limited to the following description. It is not something.

  The image forming apparatus 20 in FIG. 4 includes a photoreceptor 21 of the present invention (for example, one of the photoreceptors in FIGS. 1 to 3), a charging unit (charger) 24, an exposure unit 28, and a developing unit ( Development unit) 25, transfer unit (transfer unit) 26, cleaning unit (cleaner) 27, fixing unit (fixing unit) 31, and charge eliminating unit (not shown, attached to cleaning unit 27). Composed. Reference numeral 30 indicates a transfer sheet.

  The photosensitive member 21 is rotatably supported by the main body of the image forming apparatus 20 (not shown), and is driven to rotate in the direction of the arrow 23 around the rotation axis 22 by a driving unit (not shown). The drive means includes, for example, an electric motor and a reduction gear, and transmits the driving force to a conductive support constituting the core of the photoconductor 21, thereby rotating the photoconductor 21 at a predetermined peripheral speed. . The charger 24, the exposure unit 28, the developing unit 25, the transfer unit 26, and the cleaner 27 are arranged in this order along the outer peripheral surface of the photoconductor 21 from the upstream side in the rotation direction of the photoconductor 21 indicated by the arrow 23. It is provided toward the side.

  The charger 24 is a charging unit that charges the outer peripheral surface of the photoconductor 21 to a predetermined potential. Specifically, for example, the charger 24 is realized by a contact-type charging roller 24a, a charging brush, or a charger wire such as a corotron or a scorotron. Reference numeral 24b shows a bias power source.

  The exposure unit 28 includes, for example, a semiconductor laser as a light source, and is charged by irradiating light 28 a such as a laser beam output from the light source between the charger 24 and the developing unit 25 of the photosensitive member 21. The outer peripheral surface of the photoconductor 21 is exposed according to image information. The light 28a is repeatedly scanned in the main scanning direction in the direction in which the rotation axis 22 of the photoconductor 21 extends, and accordingly, electrostatic latent images are sequentially formed on the surface of the photoconductor 21.

  The developing unit 25 is a developing unit that develops an electrostatic latent image formed on the surface of the photoreceptor 21 by exposure with a developer. The developing unit 25 is provided facing the photoreceptor 21, and applies toner to the outer peripheral surface of the photoreceptor 21. A developing roller 25a to be supplied and a casing 25b for supporting the developing roller 25a so as to be rotatable around a rotation axis parallel to the rotation axis 22 of the photosensitive member 21 and containing a developer containing toner in the internal space thereof.

  The transfer device 26 supplies a toner image, which is a visible image formed on the outer peripheral surface of the photoconductor 21 by development, between the photoconductor 21 and the transfer device 26 from the direction of the arrow 29 by a conveying unit (not shown). It is a transfer means for transferring onto the transfer paper 30 as a recording medium. The transfer unit 26 is, for example, a non-contact type transfer unit that includes a charging unit and transfers the toner image onto the transfer paper 30 by applying a charge having a polarity opposite to that of the toner to the transfer paper 30.

  The cleaner 27 is a cleaning unit that removes and collects toner remaining on the outer peripheral surface of the photoconductor 21 after the transfer operation by the transfer device 26, and includes a cleaning blade 27 a that peels off toner remaining on the outer peripheral surface of the photoconductor 21, A recovery casing 27b for storing the toner separated by the blade 27a. The cleaner 27 is provided together with a charge eliminating lamp (not shown).

  Further, the image forming apparatus 20 is provided with a fixing device 31 as fixing means for fixing the transferred image on the downstream side where the transfer paper 30 that has passed between the photoreceptor 21 and the transfer device 26 is conveyed. . The fixing device 31 includes a heating roller 31a having a heating unit (not shown), and a pressure roller 31b that is provided to face the heating roller 31a and is pressed by the heating roller 31a to form a contact portion.

  The image forming operation by the image forming apparatus 20 is performed as follows. First, when the photosensitive member 21 is rotationally driven in the direction of the arrow 23 by the driving means, the photosensitive member 24 is provided by the charger 24 provided on the upstream side in the rotational direction of the photosensitive member 21 with respect to the image forming point of the light 28a by the exposure means 28. The surface of 21 is uniformly charged to a predetermined positive or negative potential.

  Next, light 28 a corresponding to image information is irradiated from the exposure unit 28 to the surface of the photoconductor 21. With this exposure, the surface charge of the portion irradiated with the light 28a is removed from the photosensitive member 21, and a difference occurs between the surface potential of the portion irradiated with the light 28a and the surface potential of the portion not irradiated with the light 28a. An electrostatic latent image is formed.

  Next, toner is supplied to the surface of the photosensitive member 21 on which the electrostatic latent image is formed from a developing unit 25 provided on the downstream side in the rotation direction of the photosensitive member 21 with respect to the image forming point of the light 28a by the exposure unit 28. The electrostatic latent image is developed to form a toner image.

  In synchronization with the exposure of the photosensitive member 21, the transfer paper 30 is supplied between the photosensitive member 21 and the transfer device 26. The transfer device 26 applies a charge having a polarity opposite to that of the toner to the supplied transfer paper 30, and the toner image formed on the surface of the photoreceptor 21 is transferred onto the transfer paper 30.

  Next, the transfer paper 30 onto which the toner image has been transferred is conveyed to the fixing device 31 by the conveying means, and is heated and pressurized when passing through the contact portion between the heating roller 31a and the pressure roller 31b of the fixing device 31. The toner image is fixed on the transfer paper 30 and becomes a robust image. The transfer paper 30 on which the image is formed in this way is discharged to the outside of the image forming apparatus 20 by the conveying means.

  On the other hand, the toner remaining on the surface of the photoconductor 21 even after the transfer of the toner image by the transfer unit 26 is separated from the surface of the photoconductor 21 by the cleaner 27 and collected. The charge on the surface of the photoconductor 21 from which the toner has been removed in this manner is removed by the light from the static elimination lamp, and the electrostatic latent image on the surface of the photoconductor 21 disappears. Thereafter, the photosensitive member 21 is further driven to rotate, and a series of operations starting from charging is repeated to continuously form images.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1
As the conductive support, a cylindrical conductive support made of aluminum having a diameter of 30 mm, a length of 340 mm, and a thickness of 0.8 mm was used to produce the photoconductor of FIG.
First, an aqueous polyether polyol (solid content: 35%, OH value: 60, manufactured by Nippon Polyurethane Industry Co., Ltd., product name: AQD-473) as a resin, and a blocked isocyanate compound (solid content: 37) 0.5%, NCO content: 3.7%, manufactured by Sumika Bayer Urethane Co., Ltd., product name: Bihijoule VPLS2310) 14.6 parts by weight are added to 72.5 parts by weight of water, stirred well, and the intermediate layer A coating solution (total amount 1 kg) was prepared.
The isocyanate group of the blocked isocyanate compound was in a molar ratio of 1.0 with respect to the active hydrogen-containing group of the resin.
Fill the obtained intermediate layer coating solution in the coating tank of the dip coating apparatus, immerse the conductive support, lift it, and dry the obtained coating film at room temperature and normal pressure for 5 minutes (natural drying), An intermediate precursor film having a thickness of 0.5 μm was formed.

Next, 2 parts by weight of Y-type oxotitanium phthalocyanine (manufactured by Sanyo Dye Co., Ltd.) as a charge generating substance, and 1 weight of polyvinyl butyral resin (product name: ESREC B BM-S) as a binder resin And 97 parts by weight of methyl ethyl ketone as an organic solvent were mixed and dispersed for 1 hour using a paint shaker to prepare a charge generation layer coating solution (total amount: 1 kg).
The obtained charge generation layer coating solution is applied onto the precursor film of the intermediate layer previously formed by the same dip coating method as that for the intermediate layer, and the obtained coating film is dried at room temperature and normal pressure for 1 minute. Processing (natural drying) was performed to form a charge generation layer precursor film having a thickness of 0.4 μm.

Next, 10 parts by weight of a triphenylamine-butadiene derivative represented by the following structural formula (1) as a charge transporting substance and 18 parts by weight of a polycarbonate resin (product name: Iupilon Z400, manufactured by Mitsubishi Engineering Plastics Co., Ltd.) as a binder resin Part, 0.5 part by weight of 2,6-di-t-butyl-4-methylphenol as an antioxidant, and dimethylpolysiloxane as a leveling agent (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KF-96) ) 0.004 part by weight was dissolved in 110 parts by weight of tetrahydrofuran (THF) as an organic solvent to prepare a charge transport layer coating solution (total amount: 1 kg).
The obtained charge transport layer coating solution was applied onto the previously formed charge generation layer precursor film by the same dip coating method as that for the intermediate layer, and the resulting coating film and charge generation layer precursor were obtained. The film and the intermediate layer precursor film are heat-treated at 130 ° C. and normal pressure for 1 hour, and then allowed to cool at room temperature and normal pressure for 30 minutes to form a charge transport layer having a thickness of 23 μm and a charge generation layer having a thickness of 0.4 μm An intermediate layer having a thickness of 0.5 μm was obtained.
The photoreceptor of Example 1 was produced as described above.
Excluding the preparation time of the coating liquid, the total process time required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment was about 103 minutes, of which the time required for the heat treatment was 60 minutes. It was. This means that the process time is shortened by 88 minutes compared to the conventional method in which the resin is cured immediately after the coating film is formed.

(Example 2)
First, dendritic titanium oxide fine particles (average primary particle size: minor axis: 40 to 70 nm, major axis) surface-treated with aluminum oxide (Al ₂ O ₃ ) and zirconium dioxide (ZrO ₂ ) as inorganic oxide fine particles. 200-300 nm, manufactured by Ishihara Sangyo Co., Ltd., product name: TTO-D-1) and 12 parts by weight of polyether polyol (solid content: 35%, OH value: 60, manufactured by Nippon Polyurethane Industry Co., Ltd., product) Name: AQD-473): 10.3 parts by weight and a blocked isocyanate compound (solid content: 37.5%, NCO content: 3.7%, manufactured by Sumika Bayer Urethane Co., Ltd., product name: Bihijoule VPLS2310) 11 7 parts by weight was added to 66 parts by weight of water, and dispersed for 6 hours using a paint shaker to prepare an intermediate layer coating solution (total amount: 1 kg).
The isocyanate group of the blocked isocyanate compound is in a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) are based on the cross-linked resin (total of the blocked isocyanate compound and the resin: R). The weight ratio (P / R) was 6/4.
The obtained coating solution for the intermediate layer is filled in the coating tank in the same manner as in Example 1, the conductive support is immersed and then pulled up, and the obtained coating film is dried (naturally dried) for 5 minutes at room temperature and normal pressure. Thus, an intermediate layer precursor film having a thickness of 1.0 μm was formed.

Next, a charge transport layer, a charge generation layer, and an intermediate layer were obtained in the same manner as in Example 1, and a photoreceptor of Example 2 was produced.
Excluding the preparation time of the coating liquid, the total process time required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment was about 104 minutes, of which the time required for the heat treatment was 60 minutes. It was. This means that the process time is shortened by 87 minutes compared with the conventional method in which resin curing is performed immediately after the coating film is formed.

(Example 3)
A photoconductor of Example 3 was produced in the same manner as Example 2 except that the intermediate layer coating solution was prepared with the following components.
Titanium oxide fine particles as inorganic oxide fine particles (manufactured by Ishihara Sangyo Co., Ltd., product name: TTO-D-1): 12 parts by weight Polyether polyol as resin (solid content: 35%, OH value: 60, Nippon Polyurethane Industry) Product name: AQD-473): 10.3 parts by weight,
Block isocyanate compound (solid content: 37.5%, NCO content: 3.7%, manufactured by Sumika Bayer Urethane Co., Ltd., product name: Bihijoule VPLS2310): 11.7 parts by weight Antifoaming agent (polyether foam suppression) Agent, manufactured by San Nopco Co., Ltd., product name: SN deformer 470): 0.02 parts by weight Water: 66 parts by weight The isocyanate group of the blocked isocyanate compound has a molar ratio of 1.0 to the active hydrogen-containing group of the resin. The inorganic oxide fine particles (P) had a weight ratio (P / R) of 6/4 with respect to the cross-linked resin (total of blocked isocyanate compound and resin: R).
Excluding the preparation time of the coating liquid, the total process time required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment was about 104 minutes, of which the time required for the heat treatment was 60 minutes. It was. This means that the process time is shortened by 87 minutes compared with the conventional method in which resin curing is performed immediately after the coating film is formed.

Example 4
A photoconductor of Example 4 was produced in the same manner as Example 2 except that the intermediate layer coating solution was prepared with the following components.
Titanium oxide fine particles as inorganic oxide fine particles (manufactured by Ishihara Sangyo Co., Ltd., product name: TTO-D-1): 12 parts by weight Polyether polyol as resin (solid content: 35%, OH value: 60, Nippon Polyurethane Industry) Product name: AQD-473): 10.3 parts by weight,
Block isocyanate compound (solid content: 37.5%, NCO content: 3.7%, manufactured by Sumika Bayer Urethane Co., Ltd., product name: Bihijoule VPLS2310): 11.7 parts by weight Antifoaming agent (polyether foam suppression) Agent, manufactured by San Nopco, product name: SN deformer 470): 0.02 parts by weight Dispersion stabilizer (manufactured by San Nopco, product name: Roma PWA-40): 0.03 parts by weight Water: 66 parts by weight Block isocyanate The isocyanate group of the compound has a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) have a ratio of 6 / to the cross-linked resin (total of blocked isocyanate compound and resin: R). The weight ratio (P / R) was 4.
Excluding the preparation time of the coating liquid, the total process time required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment was about 104 minutes, of which the time required for the heat treatment was 60 minutes. It was. This means that the process time is shortened by 87 minutes compared with the conventional method in which resin curing is performed immediately after the coating film is formed.

(Example 5)
A photoconductor of Example 5 was produced in the same manner as Example 2 except that the intermediate layer coating solution was prepared with the following components.
Zinc oxide fine particles as inorganic oxide fine particles (average primary particle size: 30 to 40 nm, manufactured by Teika Co., Ltd., product name: MZ300): 14 parts by weight Water-soluble nylon as resin (solid content: 20%, NH content: 10%, manufactured by Nagase ChemteX Corporation, product name: Toresin FS-350): 6.6 parts by weight Block isocyanate compound (solid content: 45%, NCO content: 7.0%, manufactured by Mitsui Chemicals Polyurethanes, Inc., Product name: Takenate WB-820): 10.4 parts by weight Antifoaming agent (oil compound, San Nopco, product name: SN deformer 777): 0.02 parts by weight Dispersion stabilizer (San Nopco, product) Name: SN Dispersant 2060): 0.035 parts by weight Water: 69 parts by weight The isocyanate group of the blocked isocyanate compound is: At a molar ratio of 1.0 to the active hydrogen-containing group of the fat, the inorganic oxide fine particles (P) have a weight ratio (P of 7/3 to the cross-linked resin (total of blocked isocyanate compound and resin: R) / R).
Excluding the preparation time of the coating liquid, the total process time required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment was about 104 minutes, of which the time required for the heat treatment was 60 minutes. It was. This means that the process time is shortened by 87 minutes compared with the conventional method in which resin curing is performed immediately after the coating film is formed.

(Example 6)
A photoconductor of Example 6 was produced in the same manner as Example 2 except that the intermediate layer coating solution was prepared with the following components.
Tin oxide fine particles (average primary particle size: 30 nm, manufactured by Mitsubishi Materials Corporation, product name: S-2000): 10 parts by weight of polyvinyl acetal as resin (solid content: 20%, OH value: inorganic oxide fine particles) 960, manufactured by Sekisui Chemical Co., Ltd., product name: KW-1): 2.8 parts by weight Block isocyanate compound (solid content: 70%, NCO content: 4.3%, manufactured by Asahi Kasei Chemicals Corporation, developed product name: X1458) 13.5 parts by weight Defoaming agent (oil compound system, manufactured by San Nopco, product name: SN deformer 777): 0.02 parts by weight Dispersion stabilizer (manufactured by Sanyo Chemical Industries, Ltd., product name: CALIBON L- 400): 0.025 parts by weight Water: 74 parts by weight The isocyanate group of the blocked isocyanate compound is 1. In the molar ratio of the inorganic oxide fine particles (P) is, (sum of blocked isocyanate compound and a resin: R) crosslinked resin had a 5/5 weight ratio with respect to (P / R).
Excluding the preparation time of the coating liquid, the total process time required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment was about 104 minutes, of which the time required for the heat treatment was 60 minutes. It was. This means that the process time is shortened by 87 minutes compared with the conventional method in which resin curing is performed immediately after the coating film is formed.

(Example 7)
A photoconductor of Example 7 was produced in the same manner as Example 2 except that the intermediate layer coating solution was prepared with the following components.
Titanium oxide fine particles as inorganic oxide fine particles (manufactured by Ishihara Sangyo Co., Ltd., product name: TTO-D-1): 12 parts by weight Aqueous polyacryl polyol as resin (solid content: 45%, OH value: 80, DIC stock) Product made by company, product name: Burnock WE-300): 9.9 parts by weight Block isocyanate compound (solid content: 42%, NCO content: 7.5%, manufactured by Nippon Polyurethane Industry Co., Ltd., developed product name: BWD-102) : 8.5 parts by weight Antifoaming agent (polyether foam suppressor, manufactured by San Nopco, product name: SN deformer 470): 0.02 parts by weight Dispersion stabilizer (produced by San Nopco, product name: SN Dispersant) 2060): 0.03 part by weight Water: 70 part by weight The isocyanate group of the blocked isocyanate compound is 1.0 with respect to the active hydrogen-containing group of the resin. Le ratio, the inorganic oxide fine particles (P) is, (sum of blocked isocyanate compound and a resin: R) crosslinked resin had a weight ratio of 6/4 with respect to (P / R).
Excluding the preparation time of the coating liquid, the total process time required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment was about 104 minutes, of which the time required for the heat treatment was 60 minutes. It was. This means that the process time is shortened by 87 minutes compared with the conventional method in which resin curing is performed immediately after the coating film is formed.

(Example 8)
A photoconductor of Example 8 was produced in the same manner as Example 2 except that the intermediate layer coating solution was prepared with the following components.
Titanium oxide fine particles as inorganic oxide fine particles (average primary particle size: 35 nm, manufactured by Teika Co., Ltd., product name: MT-500SAS): 12 parts by weight Polyvinyl acetal as a resin (solid content: 20%, OH value: 960, Sekisui Chemical Co., Ltd., product name: KW-1): 4.0 parts by weight Block isocyanate compound (solid content: 70%, NCO content: 7.9%, manufactured by Asahi Kasei Chemicals Corporation, product name: X1248) 10.3 parts by weight Antifoaming agent (oil compound system, manufactured by San Nopco, product name: SN deformer 777): 0.02 parts by weight Dispersion stabilizer (manufactured by Sanyo Chemical Industries, Ltd., product name: Caribbon L-400) : 0.03 part by weight Water: 74 parts by weight The isocyanate group of the blocked isocyanate compound has a molar ratio of 1.0 to the active hydrogen-containing group of the resin. The inorganic oxide fine particles (P) had a weight ratio (P / R) of 6/4 with respect to the cross-linked resin (total of blocked isocyanate compound and resin: R).
Excluding the preparation time of the coating liquid, the total process time required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment was about 104 minutes, of which the time required for the heat treatment was 60 minutes. It was. This means that the process time is shortened by 87 minutes compared with the conventional method in which resin curing is performed immediately after the coating film is formed.

Example 9
A photoconductor of Example 9 was produced in the same manner as Example 2 except that the intermediate layer coating solution was prepared with the following components.
Zinc oxide fine particles as inorganic oxide fine particles (average primary particle size: 35 nm, manufactured by Sakai Chemical Industry Co., Ltd., product name: FINEX 30): 12 parts by weight Water-soluble cellulose as a resin (OH value: 360, Shin-Etsu Chemical Co., Ltd.) Product name: Metrolose 65SH-50): 1.33 parts by weight Block isocyanate compound (solid content: 40%, NCO content: 5.4%, manufactured by Mitsui Chemicals Polyurethanes, product name: Takenate WB-920) : 16.7 parts by weight Antifoaming agent (oil compound type, manufactured by San Nopco, product name: SN deformer 777): 0.02 parts by weight Dispersion stabilizer (manufactured by Sanyo Chemical Industries, Ltd., product name: Elestat AP-130) ): 0.03 part by weight Water: 70 part by weight The isocyanate group of the blocked isocyanate compound is an active hydrogen-containing group of the resin. 1.0 molar ratio against inorganic oxide fine particles (P) is, (sum of blocked isocyanate compound and a resin: R) crosslinked resin had a weight ratio of 6/4 with respect to (P / R).
Excluding the preparation time of the coating liquid, the total process time required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment was about 104 minutes, of which the time required for the heat treatment was 60 minutes. It was. This means that the process time is shortened by 87 minutes compared with the conventional method in which resin curing is performed immediately after the coating film is formed.

(Example 10)
A photoconductor of Example 10 was produced in the same manner as Example 2 except that the intermediate layer coating solution was prepared with the following components.
Titanium oxide fine particles as inorganic oxide fine particles (manufactured by Ishihara Sangyo Co., Ltd., product name: TTO-D-1): 12 parts by weight Aqueous polyacryl polyol as resin (solid content: 45%, OH value: 80, DIC stock) Product name: Vernock WE-300): 13.5 parts by weight Block isocyanate compound (solid content: 42%, NCO content: 7.5%, manufactured by Nippon Polyurethane Industry Co., Ltd., developed product name: BWD-102) : 4.6 parts by weight Antifoaming agent (polyether foam suppressor, manufactured by San Nopco, product name: SN deformer 470): 0.02 parts by weight Dispersion stabilizer (produced by San Nopco, product name: SN Dispersant) 2060): 0.03 part by weight Water: 69.9 part by weight The isocyanate group of the blocked isocyanate compound is 0 with respect to the active hydrogen-containing group of the resin. In a molar ratio of 4, the inorganic oxide fine particles (P) is, (sum of blocked isocyanate compound and a resin: R) crosslinked resin had a weight ratio of 6/4 with respect to (P / R).
Excluding the preparation time of the coating liquid, the total process time required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment was about 104 minutes, of which the time required for the heat treatment was 60 minutes. It was. This means that the process time is shortened by 87 minutes compared with the conventional method in which resin curing is performed immediately after the coating film is formed.

(Example 11)
A photoconductor of Example 11 was produced in the same manner as Example 2 except that the intermediate layer coating solution was prepared with the following components.
Titanium oxide fine particles as inorganic oxide fine particles (manufactured by Ishihara Sangyo Co., Ltd., product name: TTO-D-1): 12 parts by weight Aqueous polyacryl polyol as resin (solid content: 45%, OH value: 80, DIC stock) Product name: Vernock WE-300): 12.0 parts by weight Block isocyanate compound (solid content: 42%, NCO content: 7.5%, manufactured by Nippon Polyurethane Industry Co., Ltd., developed product name: BWD-102) : 6.2 parts by weight Antifoaming agent (polyether foam suppressor, manufactured by San Nopco, product name: SN deformer 470): 0.02 parts by weight Dispersion stabilizer (produced by San Nopco, product name: SN Dispersant) 2060): 0.03 part by weight Water: 69.8 part by weight The isocyanate group of the blocked isocyanate compound is 0 with respect to the active hydrogen-containing group of the resin. 6 molar ratio, the inorganic oxide fine particles (P) is, (sum of blocked isocyanate compound and a resin: R) crosslinked resin had a weight ratio of 6/4 with respect to (P / R).
Excluding the preparation time of the coating liquid, the total process time required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment was about 104 minutes, of which the time required for the heat treatment was 60 minutes. It was. This means that the process time is shortened by 87 minutes compared with the conventional method in which resin curing is performed immediately after the coating film is formed.

(Example 12)
A photoconductor of Example 12 was produced in the same manner as Example 2 except that the intermediate layer coating solution was prepared with the following components.
Titanium oxide fine particles as inorganic oxide fine particles (manufactured by Ishihara Sangyo Co., Ltd., product name: TTO-D-1): 12 parts by weight Aqueous polyacryl polyol as resin (solid content: 45%, OH value: 80, DIC stock) Product made by company, product name: Burnock WE-300): 8.4 parts by weight Block isocyanate compound (solid content: 42%, NCO content: 7.5%, manufactured by Nippon Polyurethane Industry Co., Ltd., developed product name: BWD-102) : 10.1 parts by weight Antifoaming agent (polyether foam suppressor, manufactured by San Nopco, product name: SN deformer 470): 0.02 parts by weight Dispersion stabilizer (produced by San Nopco, product name: SN Dispersant) 2060): 0.03 part by weight Water: 69.6 part by weight The isocyanate group of the blocked isocyanate compound is 1 with respect to the active hydrogen-containing group of the resin. In a molar ratio of 4, the inorganic oxide fine particles (P) is, (sum of blocked isocyanate compound and a resin: R) crosslinked resin had a weight ratio of 6/4 with respect to (P / R).
Excluding the preparation time of the coating liquid, the total process time required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment was about 104 minutes, of which the time required for the heat treatment was 60 minutes. It was. This means that the process time is shortened by 87 minutes compared with the conventional method in which resin curing is performed immediately after the coating film is formed.

(Example 13)
A photoconductor of Example 13 was produced in the same manner as Example 2 except that the intermediate layer coating solution was prepared using the following components.
Titanium oxide fine particles as inorganic oxide fine particles (manufactured by Ishihara Sangyo Co., Ltd., product name: TTO-D-1): 12 parts by weight Aqueous polyacryl polyol as resin (solid content: 45%, OH value: 80, DIC stock) Product name: Burnock WE-300): 7.8 parts by weight Block isocyanate compound (solid content: 42%, NCO content: 7.5%, manufactured by Nippon Polyurethane Industry Co., Ltd., developed product name: BWD-102) : 10.7 parts by weight Antifoaming agent (polyether foam suppressor, manufactured by San Nopco, product name: SN deformer 470): 0.02 parts by weight Dispersion stabilizer (manufactured by San Nopco, product name: SN Dispersant) 2060): 0.03 part by weight Water: 69.5 part by weight The isocyanate group of the blocked isocyanate compound is 1 with respect to the active hydrogen-containing group of the resin. 6 molar ratio, the inorganic oxide fine particles (P) is, (sum of blocked isocyanate compound and a resin: R) crosslinked resin had a weight ratio of 6/4 with respect to (P / R).
Excluding the preparation time of the coating liquid, the total process time required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment was about 104 minutes, of which the time required for the heat treatment was 60 minutes. It was. This means that the process time is shortened by 87 minutes compared with the conventional method in which resin curing is performed immediately after the coating film is formed.

(Example 14)
A photoconductor of Example 14 was produced in the same manner as in Example 8, except that the charge generation layer coating solution was prepared with the following components.
Y-type oxotitanium phthalocyanine as a charge generating substance (manufactured by Sanyo Dye Co., Ltd.): 2 parts by weight Polyvinyl butyral resin (OH number: 165, product made by Sekisui Chemical Co., Ltd., product name: BM-1) as a cured resin: 0.50 parts by weight Block isocyanate compound as a curing agent (solid content: 80%, NCO content: 12.5%, manufactured by Asahi Kasei Chemicals Corporation, product name: Duranate TPA-880E): 0.61 parts by weight Organic solvent Methyl ethyl ketone as: 97 parts by weight The total process time required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment, excluding the preparation time of the coating liquid, is about 104 minutes, of which the heat treatment is necessary The time spent was 60 minutes. This means that the process time is shortened by 87 minutes compared with the conventional method in which resin curing is performed immediately after the coating film is formed.

(Comparative Example 1)
Except that the intermediate layer coating solution was prepared with the following components, an attempt was made to produce a photoreceptor of Comparative Example 1 in the same manner as in Example 2 (organic solvent system, curing system). However, when the intermediate layer precursor film was formed and then the charge generation layer coating solution was applied, it was confirmed that a portion of the intermediate layer precursor film was dissolved in the charge generation layer coating solution. Therefore, we abandoned the creation of the photoconductor.
Zinc oxide fine particles as inorganic oxide fine particles (Taika Co., Ltd., product name: MZ-300): 12 parts by weight Butyral as resin (Sekisui Chemical Co., Ltd., product name: BM-1): 3.8 wt. Part Block isocyanate compound (solid content: 75%, NCO content: 11.2%, manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Sumidur BL3175): 5.6 parts by weight Methyl ethyl ketone as organic solvent: 78.6 Parts by weight

(Comparative Example 2)
A photoconductor of Comparative Example 2 was produced in the same manner as in Example 2 except that the intermediate layer coating solution was prepared with the following components (aqueous, non-cured).
Titanium oxide fine particles as inorganic oxide fine particles (Ishihara Sangyo Co., Ltd., product name: TTO-D-1): 6 parts by weight Polyvinyl acetal as a resin (solid content: 20%, OH value: 570, Sekisui Chemical Co., Ltd.) Product made by company, product name: KW-3): 20 parts by weight Water: 74 parts by weight Excluding the preparation time of the coating liquid, the total process required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment The time was about 104 minutes, of which the time required for the heat treatment was 60 minutes. This means that the process time is shortened by 87 minutes compared with the conventional method in which resin curing is performed immediately after the coating film is formed.

(Comparative Example 3)
After applying the coating solution for the intermediate layer and before applying the coating solution for the charge generation layer, heat treatment for 30 minutes at a temperature of 130 ° C. and normal pressure, followed by cooling at room temperature and normal pressure for 1 hour. In the same manner as in Example 7, a photoconductor of Comparative Example 3 was produced.
Excluding the preparation time of the coating liquid, the total process time required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment was about 191 minutes, of which the time required for the heat treatment was 90 minutes. It was.

(Comparative Example 4)
After applying the coating solution for the intermediate layer and before applying the coating solution for the charge generation layer, heat treatment for 30 minutes at a temperature of 130 ° C. and normal pressure, followed by cooling at room temperature and normal pressure for 1 hour. In the same manner as in Example 8, a photoconductor of Comparative Example 4 was produced.
Excluding the preparation time of the coating liquid, the total process time required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment was about 191 minutes, of which the time required for the heat treatment was 90 minutes. It was.

(Comparative Example 5)
After applying the coating solution for the intermediate layer and before applying the coating solution for the charge generation layer, heat treatment for 30 minutes at a temperature of 130 ° C. and normal pressure, followed by cooling at room temperature and normal pressure for 1 hour. In the same manner as in Example 9, a photoconductor of Comparative Example 5 was produced.
Excluding the preparation time of the coating liquid, the total process time required for the application of the coating liquid, the drying treatment of the obtained coating film and the heat treatment was about 191 minutes, of which the time required for the heat treatment was 90 minutes. It was.

  Table 1 shows the materials and weight ratios P / R used in Examples 1 to 9 and Comparative Examples 1 to 5.

(Evaluation)
(1) Electrical Characteristics and Environmental Stability of Photoreceptor The photoreceptor obtained in Examples 1 to 14 and Comparative Examples 1 to 5 is a surface potential meter (Trek) so that the surface potential of the photoreceptor in the image forming process can be measured. It was mounted on a commercially available digital copying machine (manufactured by Sharp Corporation, model: MX-M450) in which a measurement probe of model No .: MODEL344) was incorporated, and the electrical characteristics and environmental stability of each photoconductor were evaluated.

First, in an N / N environment at a temperature of 25 ° C. and a relative humidity of 50%, the surface potential of the photoconductor immediately after the charging operation by the charger was measured as a charging potential V0 (V). Further, the surface potential of the photoreceptor immediately after being exposed by laser light (wavelength: 780 nm) was measured as a residual potential VL (V) in an N / N environment.
Further, the residual potential VL (V) is measured in an N / H environment at a temperature of 25 ° C. and a relative humidity of 85% and in an N / L environment at a temperature of 25 ° C. and a relative humidity of 5% in the same manner as in the N / N environment. These differences were obtained as potential fluctuation ΔVL (V). That is, it can be evaluated that the smaller the potential fluctuation ΔVL (V), the better the environmental stability (environmental characteristics).

Next, in a N / N environment at a temperature of 25 ° C. and a relative humidity of 50%, a test image having a predetermined pattern (a character test chart defined in ISO 19752) was continuously copied on 100,000 sheets of recording paper, In the same manner as in the initial stage, the surface potential of the photoconductor immediately after the charging operation is measured as a charging potential V0 (V), and the surface potential of the photoconductor after exposure is measured as a residual potential VL (V). It was determined as a potential fluctuation ΔVLS (V) which is an index of fatigue characteristics.
The obtained results are shown in Table 2.

(2) Acetone resistance (wipe test with acetone)
The surface of the photoreceptor obtained in Examples 1 to 14 and Comparative Examples 1 to 5 was wiped with a waste impregnated with tetrahydraphrone (THF) to remove the photosensitive layer formed on the intermediate layer, exposing the intermediate layer. I let you. Next, the exposed intermediate layer was wiped with a cloth impregnated with acetone, and the results were classified according to the following criteria.
(Standard) ○: No change
Δ: A part of the surface moves to the waste but cannot be completely wiped off.
×: Completely wiped off

Before the formation of the precursor film of the photosensitive layer in Comparative Examples 3 to 5, the intermediate layer obtained by thermosetting the precursor film of the intermediate layer did not dissolve in acetone and could not be wiped off.
On the other hand, the intermediate layer which was dried under the conditions where the resin was not cured in Examples 1 to 9 and 11 to 13 and then heated together with the precursor film of the photoreceptor layer was also the same as the intermediate layer of Comparative Examples 3 to 5 It did not dissolve in acetone and could not be wiped off.
Moreover, although the trace was confirmed in the waste cloth slightly in the intermediate | middle layer in Example 10, it was not wiped off easily.
The intermediate layer of Comparative Example 2 was not a thermosetting film but dissolved in acetone and wiped off.
The obtained results are shown in Table 2.

From the results of Tables 1 and 2, the following can be understood.
(1) A coating solution for an intermediate layer is applied, and the resulting coating film is dried under conditions where the resin is not cured to form a precursor film of the intermediate layer, and then a coating for a photosensitive layer using an organic solvent as a medium. A coating solution is applied to form a precursor film of the photosensitive layer, and the precursor film of the intermediate layer and the precursor film of the photosensitive layer are simultaneously heat-treated to cure the precursor film of the intermediate layer with resin and Photoconductors (Examples 1 to 14) prepared by drying the precursor film to obtain an intermediate layer and a photosensitive layer were prepared by a conventional method of forming a photosensitive layer after curing the precursor film of the intermediate layer. The performance equivalent to that of the photoreceptor (Comparative Examples 3 to 5) is obtained. (2) According to the wiping test with acetone, the intermediate layer of the photoreceptors of Examples 1 to 14 is the photoreceptor of Comparative Examples 3 to 5. (3) The method for producing the photoconductors of Examples 1 to 14 is a comparative example. The time required for the heat treatment can be shortened to 2/3 and the total time can be shortened to about a half or more as compared with the manufacturing method of the photoconductor of .about.5. That is, according to (1) to (3), The manufacturing method of the body can shorten the energy used and the time required for the production by eliminating the time for curing the precursor film of the intermediate layer of the conventional method while maintaining the performance as a photoreceptor.

(4) According to the result of Example 14, even when a curable type is used for the charge generation layer, the same performance as in the case of the non-curable charge generation layer (Example 8) can be obtained (5 ) According to the result of Comparative Example 1, when a conventional organic solvent intermediate layer coating solution is used, charge generation occurs when the charge generation layer is subsequently applied without sufficient drying step after the intermediate layer application. There is a problem that the intermediate layer dissolves in the solvent in the layer coating solution.

1 conductive support 2 intermediate layer (undercoat layer)
3 Charge Generation Layer 4 Charge Transport Layer 5 Multilayer Type Photosensitive Layer 5 ′ Single Layer Type Photosensitive Layer

20 Image forming apparatus 22 Axis of rotation 23, 29 Arrow 24 Charging means (charger)
24a Charging roller 24b Bias power supply 25 Developing means (developer)
25a Developing roller 25b Casing 26 Transfer means (transfer device)
27 Cleaning means (cleaner)
27a Cleaning blade 27b Recovery casing 28 Exposure means 28a Light 30 Transfer paper 31 Fixing means (fixing device)
31a Heating roller 31b Pressure roller

Claims (9)

(A) On the conductive support, an intermediate layer coating solution containing a blocked isocyanate compound, a resin having an active hydrogen-containing group capable of reacting with an isocyanate group in the blocked isocyanate compound, and water is applied, A step of forming a precursor film of an intermediate layer by drying treatment under a condition in which the obtained coating film is not cured with a resin;
(B) On the precursor film of the intermediate layer, a step of applying a photosensitive layer coating solution using an organic solvent as a medium to form a precursor film of the photosensitive layer;
(C) The intermediate layer precursor film and the photosensitive layer precursor film are simultaneously heat-treated to cure the intermediate layer precursor film with resin and to dry the photosensitive layer precursor film. And a method for producing an electrophotographic photosensitive member, comprising the step of obtaining a photosensitive layer.   2. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the drying treatment in the step (A) comprises holding the coating film at normal temperature and pressure for 1 to 30 minutes.   The heat treatment in the step (C) comprises holding the precursor film of the intermediate layer and the precursor film of the photosensitive layer at a temperature of 110 to 150 ° C. and a normal pressure for 15 to 90 minutes. A method for producing the electrophotographic photosensitive member according to the description.   In the step (B), a charge generation layer coating solution containing a charge generation material and a charge transport layer coating solution containing a charge transport material are applied on the precursor film of the intermediate layer in this order or reverse order. A step of forming a precursor film of a laminated type photosensitive layer, or a single layer type photosensitive layer coating solution containing a charge generating substance and a charge transporting substance is applied on the precursor film of the intermediate layer. The method for producing an electrophotographic photosensitive member according to any one of claims 1 to 3, which is a step of forming a precursor film of a layer-type photosensitive layer.   The method for producing an electrophotographic photosensitive member according to claim 1, wherein the active hydrogen-containing group is a hydroxyl group or an amide group.   The electrophotographic photoreceptor according to claim 1, wherein the isocyanate group is present in the blocked isocyanate compound at a molar ratio of 0.5 to 1.5 with respect to the active hydrogen-containing group. Manufacturing method.   The method for producing an electrophotographic photosensitive member according to any one of claims 1 to 6, wherein the blocked isocyanate compound has a structure in which hexamethylene diisocyanate or isophorone diisocyanate is blocked with an oxime or lactam blocking agent.   8. The resin composition according to claim 1, wherein the resin is selected from polyether polyol resins, polyester polyol resins, polyacryl polyol resins, polyvinyl alcohol resins, polyvinyl acetal resins, cellulose, and polyamide resins. A process for producing an electrophotographic photoreceptor according to 1.   The method for producing an electrophotographic photosensitive member according to claim 1, wherein the intermediate layer coating solution further contains inorganic oxide fine particles.

Images