JP2010271652A - Electrophotographic photoreceptor and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an electrophotographic photoreceptor with less environmental burden and high production stability, the photoreceptor showing little changes in sensitivity by the environment dependency and giving high-quality images even in a low temperature and low humidity environment. <P>SOLUTION: The method aims to manufacture an electrophotographic photoreceptor including an intermediate layer and a photosensitive layer in this order on a conductive support, the photosensitive layer containing a N-N'-bisenamine compound expressed by general formula (1) as a charge transporting substance. The intermediate layer is formed by applying a coating liquid for forming the intermediate layer on a conductive support, the liquid containing an aqueous block isocyanate compound and a resin having two or more active hydrogen-containing groups reactive with the isocyanate group in an aqueous medium, followed by thermally curing the liquid. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an electrophotographic photoreceptor and an electrophotographic image forming apparatus using the photoreceptor.

At present, an electrophotographic photoreceptor (hereinafter, also simply referred to as “photoreceptor”) is formed by laminating an intermediate layer (also referred to as “undercoat layer”) and a photosensitive layer containing a photoconductive material on a conductive support. The configuration is the mainstream.
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 a function.

  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.

  The melamine resin described in Japanese Patent No. 3657138 (Patent Document 1), the phenol resin described in Japanese Patent No. 2707341 (Patent Document 2), and resins such as methoxymethylated nylon are used in large quantities at the time of production. A part of the formaldehyde that is formed is occluded inside as an unreacted substance, and this formaldehyde is released in the process of thermal crosslinking during the formation of the intermediate layer. Formaldehyde is said to be one of the causative substances of sick house syndrome, and is currently listed as a target substance in the Air Pollution Control Law. In order to prevent the release of generated formaldehyde into the atmosphere, a recovery facility is required and costs are high.

  Incidentally, in recent years, electrophotographic image forming apparatuses (hereinafter also simply referred to as “image forming apparatuses”) such as copying machines, printers, facsimile machines, and electrophotographic plate making machines have been reduced in size and increased in image forming speed. Long life has been required. In such an image forming apparatus, an electrophotographic photosensitive member in which a photosensitive layer is provided on the outer peripheral surface of a cylindrical or columnar conductive support is generally used, and in order to reduce the size of the image forming apparatus, It is necessary to reduce the diameter of the photoreceptor.

However, since the distance from the exposure position to the development position is short for a photoconductor with a small diameter, if the electrophotographic process is performed at a high speed in order to increase the image formation speed, the time from exposure to development is shortened. The following problems arise.
For example, if a photoconductor with low responsiveness, that is, a photoconductor with a slow decay rate of the surface potential after exposure is used, development is performed in a state where the surface potential of the portion to be erased by exposure is not sufficiently attenuated. Become. As a result, in the case of regular development, a phenomenon called background smearing occurs in which toner adheres to the white portion of the image, and in the case of reversal development, the image density decreases.

Therefore, in order to achieve both a reduction in the size of the image forming apparatus and an increase in the image forming speed, it is required to improve the responsiveness of the photoreceptor.
It is known that the responsiveness of the photoreceptor greatly depends on the charge mobility of the charge transport material. Therefore, by using a charge transport material with high charge mobility for the photoreceptor to improve responsiveness, the diameter of the photoreceptor is reduced and the speed of the electrophotographic process is improved. A technique for realizing an increase in speed has been proposed (see Non-Patent Document 1).
In addition, there has been proposed a technique for realizing a reduction in the size of an image forming apparatus and an increase in an image forming speed by using a photoconductor provided with a charge transport layer having a specific charge mobility (Japanese Patent Laid-Open No. 8-62862). No. (Patent Document 3)).

Japanese Patent No. 3657138 Japanese Patent No. 2707341 JP-A-8-62862

Masaharu Shirai, “New OPC Technology for Laser Exposure“ IR-ST ””, Fuji Xerox Technical Report, No. 11, [online], 1996, Fuji Xerox Co., Ltd., Internet <URL: http://www.fujixerox. co.jp/company/tr/tr96/Masaharu_Shirai/M_Shi101.html>

  In order to eliminate the occurrence of volatile organic compounds (VOC) and eliminate the risk of fire, it is conceivable to form the intermediate layer with a resin having a high affinity for water. Because of its high moisture adsorption and affinity, there is a problem that the physical properties are very dependent on the environment, and the characteristics of the photoconductor provided with such an intermediate layer change depending on the 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.

  On the other hand, the NN ′ bis-enamine structure compound having high charge mobility that can contribute to the reduction in the diameter of the photoreceptor and the speed of the electrophotographic process is dependent on the humidity under high humidity, and is sensitive to the environment. There is a drawback that it tends to cause fluctuations. Such fluctuations in sensitivity appear as image defects such as background stains on an actual image, so that the photoreceptor is required to have excellent moisture resistance.

  Therefore, the present invention provides a highly reliable electrophotographic method in which the intermediate layer is made of a resin having a high affinity for water, while the sensitivity variation due to environmental dependence is small, and a high-quality image can be obtained even in a low temperature and low humidity environment. The object was to provide a photoreceptor.

  Thus, the present invention has at least an intermediate layer and a photosensitive layer in this order on a conductive support, and the intermediate layer can react with at least an aqueous blocked isocyanate compound and an isocyanate group on the conductive support. Obtained by applying an intermediate layer-forming coating solution obtained by dissolving or dispersing an aqueous resin having two or more active hydrogen-containing groups in an aqueous medium and then thermally curing the photosensitive layer as a charge transport material. The following general formula (1)

(In the formula, A represents an arylene group which may have a substituent, a divalent heterocyclic group which may have a substituent, an alkylene group which may have a substituent, or a group —Ar ₃ — W—Ar ₄ — (wherein Ar ₃ and Ar ₄ are each independently an arylene group which may have a substituent or a divalent heterocyclic group which may have a substituent; A bond, a cycloalkylidene group that may have a substituent, or a divalent chain hydrocarbon group that may have a substituent), and Ar ₁ may have a substituent An aryl group, a monovalent heterocyclic group that may have a substituent, an aralkyl group that may have a substituent, or a heterocyclic alkyl group that may have a substituent, Ar ₂ is a substituted group An aryl group which may have a group or a divalent heterocyclic group, and Z represents an atomic group necessary for forming a ring together with Ar _2. )
And an N, N′-bisenamine compound represented by the formula:

  The present invention also provides the electrophotographic photosensitive member, a charging unit that charges the electrophotographic photosensitive member, and an exposure unit that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image. Developing means for developing the electrostatic latent image to form a toner image; transfer means for transferring the toner image onto a recording material; and fixing the transferred toner image on the recording material to form an image. An image forming apparatus comprising: a fixing unit to be formed; a cleaning unit that removes and collects toner remaining on the electrophotographic photosensitive member; and a static eliminating unit that neutralizes surface charges remaining on the electrophotographic photosensitive member. I will provide a.

  According to the present invention, high responsiveness is exhibited even in a low-temperature and low-humidity environment, sensitivity fluctuation due to the environment is small, and thus high-quality images can be provided even in various environments such as a low-temperature and low-humidity environment. A reliable electrophotographic photoreceptor is provided.

  Further, according to the image forming apparatus provided with the electrophotographic photosensitive member of the present invention, it is small and has a high image forming speed, and can provide a high-quality image even in various environments such as a low temperature and low humidity environment, and has excellent durability. A highly reliable image forming apparatus can be realized.

FIG. 2 is a schematic cross-sectional view illustrating a configuration of a main part of one embodiment of the photoreceptor of the present invention. 1 is a schematic side view illustrating a configuration of an embodiment of an image forming apparatus of the present invention.

Electrophotographic Photosensitive Member The electrophotographic photosensitive member of the present invention has at least an intermediate layer and a photosensitive layer in this order on a conductive support, and the intermediate layer is at least an aqueous blocked isocyanate on the conductive support. It is obtained by applying a thermosetting treatment after applying a coating solution for forming an intermediate layer in which an aqueous resin having two or more active hydrogen-containing groups capable of reacting with a compound and an isocyanate group is dissolved or dispersed in an aqueous medium, The photosensitive layer as a charge transport material is represented by the following general formula (1)

(Wherein A, Ar ₁ , Ar ₂ and Z are as defined above)
The N, N'-bisenamine compound shown by these is contained.

In the photoreceptor of the present invention, the intermediate layer is obtained by dissolving or dispersing, in an aqueous medium, an aqueous resin having at least two aqueous hydrogenated groups capable of reacting with an aqueous blocked isocyanate compound and an isocyanate group on a conductive support. It is an intermediate layer obtained by applying a thermosetting treatment after applying the intermediate layer forming coating solution.
In general, a photoreceptor having an intermediate layer formed of an aqueous resin having a high affinity for water is inferior in moisture resistance. However, in the present invention, the aqueous resin is subjected to a thermosetting reaction with an isocyanate compound, so that a hydrophilic functional group in the aqueous resin is obtained. Since the number of groups is reduced and the coating film is densified as a cured film, the moisture resistance of the photoreceptor is improved and excellent environmental stability can be obtained.

  Further, by combining the intermediate layer as described above with a photosensitive layer containing an enamine compound having a specific structure represented by the general formula (1), the photoreceptor of the present invention has high sensitivity and high moisture resistance. Therefore, it is possible to provide a high-quality image with little variation in sensitivity due to environmental dependence.

The photoreceptor of the present invention will be specifically described below with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing the configuration of the main part of three forms of the photoreceptor of the present invention.

FIG. 1 (a) shows the main part of a multilayer photoreceptor in which the photosensitive layer is a multilayer photosensitive layer (also referred to as “function-separated photosensitive layer”) formed by laminating a charge generation layer and a charge transport layer in this order. The configuration is shown.
This type of photoreceptor has an intermediate layer 2 and a laminate type photosensitive layer 5 in this order on a conductive support 1, and the laminate type photosensitive layer 5 includes a charge generation layer 3 containing a charge generation substance and a charge generation layer. The charge transport layer 4 containing a transport material is formed in this order.

FIG. 1B shows the configuration of the main part of a laminated photoreceptor, which is an inverted two-layer laminated photosensitive layer in which the photosensitive layer is formed by laminating a charge transport layer and a charge generation layer in this order.
This type of photoreceptor has an intermediate layer 2 and a laminate type photosensitive layer 5 in this order on a conductive support 1, and the laminate type photosensitive layer 5 includes a charge transport layer 4 containing a charge transport substance and a charge. The charge generation layer 3 containing the generation material is formed in this order.

FIG. 1C shows 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.
This type of photosensitive member has an intermediate layer 2 and a single-layered photosensitive layer 5 ′ containing a charge generating material and a charge transporting material in this order on a conductive support 1.

[Conductive support]
The conductive support 1 is not particularly limited as long as it can function as a support member for each of the other layers (at least the intermediate layer 2 and the photosensitive layers 5 and 5 ′) while serving as an electrode of the photoreceptor. Can be used.

  Specific examples include aluminum, aluminum alloys, copper, brass, zinc, nickel, stainless steel, chromium, molybdenum, vanadium, indium, titanium, gold, platinum and other metal and alloy materials; 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 include those obtained by depositing or coating 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. Among these, a cylindrical or columnar conductive support having a diameter of 10 to 180 mm is preferable.

In order to improve the image quality, the surface of the conductive support is subjected to irregular reflection treatment such as anodic oxide film treatment, surface treatment with chemicals and hot water, coloring treatment, and surface roughening as necessary. May be.
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.

[Middle layer]
The intermediate layer 2 has a function of preventing charge injection from the conductive support 1 to the laminated photosensitive layer 5 or the single-layered photosensitive layer 5 ′. That is, a decrease in chargeability of the multilayer photosensitive layer or single-layer photosensitive layer is suppressed, a decrease in surface charge other than a portion to be erased by exposure is suppressed, and 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.

  Further, the intermediate layer 2 covering the surface of the conductive support 1 reduces the degree of unevenness, which is a defect on the surface of the conductive support, and makes the surface uniform. The film formability can be improved, and the adhesion (adhesiveness) between the conductive support and the multilayer photosensitive layer or the single-layer photosensitive layer can be improved.

  In the present invention, the intermediate layer 2 is obtained by dissolving or dispersing, in an aqueous medium, an aqueous resin having at least two active hydrogen-containing groups capable of reacting with an aqueous blocked isocyanate compound and an isocyanate group on the conductive support 1. After the intermediate layer forming coating solution is applied, it is formed by heat curing treatment.

  In the present invention, the “aqueous blocked isocyanate compound” is a water-soluble or water-dispersible compound having a plurality of isocyanate groups in one molecule (hereinafter also referred to as “aqueous isocyanate compound”), and the isocyanate group is blocked. It is protected with an agent (protecting group), and the blocking agent is removed by heating. In the present invention, the aqueous blocked isocyanate compound is an aqueous resin (hereinafter simply referred to as “active hydrogen-containing group”) having two or more active hydrogen-containing groups capable of reacting with isocyanate groups (hereinafter also simply referred to as “active hydrogen-containing groups”). It can act as a crosslinking agent (or curing agent). That is, the aqueous resin is cross-linked by addition reaction of the plurality of isocyanate groups in the isocyanate compound from which the blocking agent has been removed by heating with the plurality of active hydrogen-containing groups in the aqueous resin.

The aqueous isocyanate compound is a water-soluble form or a self-emulsifying form obtained by modifying organic isocyanate with various hydrophilic groups such as polyethylene oxide, carboxyl group or sulfonic acid group, or a surfactant (for example, a nonionic surfactant or It is a compound in a water dispersible form that is forcibly emulsified by anionic surface activity).
Examples of surfactants include NAROACTY CL, Ionette M, Ionette T, Emalmin, New Pole PF (above, nonionic surfactant), Sandet, Sanmorin OT-70 (above, anion) manufactured by Sanyo Chemical Industries, Ltd. Surfactants).

  Examples of the organic isocyanate from which an aqueous isocyanate compound can be obtained include phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, naphthylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, hydrogenated diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate. And hydrogenated toluene diisocyanate, tetramethylene xylylene diisocyanate; and biuret, uretdione, carbodiimide, isocyanurate, and urethane imine modifications of the isocyanate.

  Among these organic isocyanates, aliphatic diisocyanate-based isocyanates such as hexamethylene diisocyanate and isophorone diisocyanate tend to have an affinity for water (so that it is easy to make an aqueous isocyanate compound), and the crosslinking density It is particularly preferable because it is easy to increase the value.

  The aqueous blocked isocyanate compound can be used alone or in combination of two or more.

  As blocking agents for blocking (protecting) isocyanate groups, active methylene compounds such as ethyl acetate and acetylacetone; mercaptan compounds such as butyl mercaptan and dodecyl mercaptan; acid amide compounds such as acetanilide and acetic acid amide; ε-caprolactam; Lactam compounds such as δ-valerolactam and γ-butyrolactam; acid imide compounds such as succinimide and maleic imide; imidazole compounds such as imidazole and 2-methylimidazole; urea such as urea, thiourea and ethyleneurea Compounds: formamide oxime, acetaldoxime, acetone oxime, methyl ethyl ketoxime, methyl isobutyl ketoxime, cyclohexanone oxime, and other oxime compounds; diphenylaniline, aniline Carbazole, ethyleneimine, amine compounds such as polyethyleneimine and the like, these blocking agents can be used individually or in combination of two or more thereof.

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.
In addition, since the isocyanate group easily reacts with water, the blocking agent may be detached after the water in the coating film formed by applying the coating liquid for forming the intermediate layer on the conductive support volatilizes. In addition, it is preferable to use a blocking agent having a desorption temperature of 110 ° C. or higher.
Therefore, the aqueous blocked isocyanate compound preferably has a structure in which hexamethylene diisocyanate or isophorone diisocyanate is blocked with an oxime or lactam blocking agent.

As an aqueous block isocyanate compound, for example,
Manufactured by Sumika Bayer Urethane Co., Ltd., product names: Bihijoule BL 5140, BL 5235 and VP LS 2310);
Product name: Takenate WB-700, WB-820 and WB-920;
Nippon Polyurethane Industry Co., Ltd., developed product name: BWD-102
Asahi Kasei Chemicals Corporation product name: X1238, X1248 and X1258
Etc.

The active hydrogen-containing group that can react with the isocyanate group is preferably a hydroxyl group or an amide group that can react with the isocyanate group with high efficiency.
That is, the aqueous resin having an active hydrogen-containing group has two or more hydroxyl groups or amide groups to form a crosslinked structure with a deprotected isocyanate compound (if it has only one functional group, it has a crosslinked structure). A water-based resin having a high molecular weight is preferred. Here, “aqueous resin” refers to a water-soluble or water-dispersible resin.

  As an aqueous resin having two or more hydroxyl groups or amide groups, a polyol resin, a polyvinyl acetal resin or a polyamide resin is suitable. These resins can be well dispersed or dissolved in water by controlling the structure. In addition, since these resins have high adhesion to the substrate and can be formed in a state where the intermediate layer is satisfactorily adhered to the conductive support, image defects due to poor contact with the conductive support are also caused when the photosensitive member is used. It can be effectively prevented.

As an aqueous resin having two or more active hydrogen-containing groups, for example,
Product name: AQD-457 and AQD-473, manufactured by Asahi Glass Co., Ltd., product name: Exenol 420 and 720, manufactured by Sanyo Chemical Industries, Ltd., product name: Sannix GP-400, GP-700 And polyether polyol resins (polyol compound 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 resin);

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;
Product name: Water-soluble nylon (polyamide compound resin) such as Toresin FS-350 and FS-500, manufactured by Nagase ChemteX Corporation
Etc.

In the present invention, the molar ratio of the blocked isocyanate group (H) in the aqueous blocked isocyanate compound in the intermediate layer forming coating solution to the active hydrogen-containing group (B) in the aqueous resin having an active hydrogen-containing group (H / B) is preferably 0.5 or more and 1.5 or less, more preferably 0.5 or more and 1.2 or less, and still more preferably 0.6 or more and 1.1 or less.
When the molar ratio H / B is less than 0.5 or exceeds 1.5, many unreacted functional groups remain in the coating film (intermediate layer) after the heat treatment, resulting in a low crosslinking density. A photoreceptor having such an intermediate layer may have a reduced environmental stability.

The intermediate layer may further contain inorganic oxide fine particles.
The inorganic oxide fine particles adjust the volume resistance value of the intermediate layer to be formed, prevent the injection of carriers from the conductive support to the photosensitive layer, and maintain the electrical characteristics of the photosensitive member in various environments Have

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. Among these, fine particles of titanium oxide, zinc oxide and aluminum oxide are preferable in terms of dielectric constant, and fine particles of titanium oxide and zinc oxide are particularly preferable.
The shape of the inorganic oxide fine particles may be any of dendritic, acicular and granular.
The number 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): 20 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), STR-60 (shape: needle shape), 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, average primary particle size: 65 nm), manufactured by Hakusui Tech Co., Ltd.
And zinc oxide fine particles.

The inorganic oxide fine particles (P) have a weight ratio (P / R) in the range of 1/1 to 9/1 with respect to the cross-linked resin (total R of the resin having an aqueous blocked isocyanate compound and an active hydrogen-containing group). It is preferable.
When the weight ratio P / R is less than 1/1, the characteristics of the intermediate layer depend on the characteristics of the cross-linked resin, and the characteristics of the photoconductor may change greatly particularly 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 and black. Image defects such as spots may occur.

The intermediate layer may also contain an electron transport material to adjust the conductivity of the intermediate layer.
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-forming coating solution can be prepared by dissolving or dispersing an aqueous blocked isocyanate compound, an aqueous resin having an active hydrogen-containing group, and, if desired, the above-described additives in an aqueous medium.
The aqueous medium means water or a mixed medium of water and a hydrophilic organic solvent such as a lower alcohol (for example, C _{1 to} C ₄ alcohol), but in the present invention, only water is preferable.

In order to disperse the constituent components of the coating liquid for forming the intermediate layer, particularly the inorganic oxide fine particles, in an aqueous medium, a general disperser such as a paint shaker, an ultrasonic disperser, a ball mill, or a sand mill may be used.
In order to stabilize the dispersion state, a dispersion stabilizer may be added to the intermediate layer forming coating solution.

  Examples of the dispersion stabilizer include Sanyo Kasei Co., Ltd., product names: Carribbon L-400, Elestat AP 130, Sunspear PS 8, PDN-173, Ionette S-85, New Pole PE-61, and San Nopco Co., Ltd. Product name: Rome PWA-40, Nobco Santo RFA, SN Dispersant 2060, 5020, 5029, 5468, 7347C and SN Wet P, manufactured by Nissin Chemical Industry Co., Ltd., Product name: Surfinol 104E and Olphin PD-003, Kao Product name: Poise 520, 530, Homogenol L 100, Daiichi Kogyo Seiyaku Co., Ltd., Charoru AN-103P, AH-144P, Discoat N-14, Toho Chemical Industry Co., Ltd., Product name: Dibrozin A-100, Neoscope 30, etc. are mentioned.

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

  The antifoaming agent is added for the purpose of suppressing the generation of bubbles in the intermediate layer forming coating solution. Therefore, the addition amount is an amount that can achieve this purpose, and is usually very small. When an aqueous resin is added to an aqueous medium, foaming may be caused by dispersion or stirring during preparation to reduce dispersion or stirring efficiency, and foaming may be caused during coating to cause coating film defects. Antifoaming agents suppress foaming that can cause such problems.

  Examples of the antifoaming agent include polyether-based, silicone-based, oil compound-based, and emulsion-based antifoaming agents. As specific examples, for example, product names: SN deformers 444, 470, 485, PC (polyether type), SN deformers 1311, 1316 (silicone type), SN deformers 777, 328, 480, H2 (manufactured by San Nopco Co., Ltd.) Oil compound type), manufactured by Nissho Sangyo Co., Ltd., product name: TSA750 (oil compound type), TSA770 (emulsion type), manufactured by Toray Dow Corning Co., Ltd .: product name: silicone emulsion such as DK Q1-1247, etc. Is mentioned.

  Examples of the viscoelasticity adjusting agent include viscoelasticity adjusting agents such as polyether-based, urethane-modified polyether-based, modified polyacrylic acid-based, and water-soluble cellulose ether. Specific examples include, for example, San Nopco Co., Ltd., product names: SN thickener 601, A816 (polyether type), SN thickener 607 (urethane modified polyether type), SN thickener 617 (modified polyacrylic acid type), Shin-Etsu Chemical. Kogyo Co., Ltd. product name: Water-soluble cellulose ethers such as Metrose 65SH-4000.

  The amount of the viscoelasticity modifier added is, for example, 0.001 to 0.2, preferably 0.005 to 0.1, and more preferably 0.005 to 0.5, based on the weight ratio to the crosslinked resin (R). .

As an antiseptic | preservative, the organic nitrogen sulfur type compound like the product made from a San Nopco Co., Ltd. product name: Nopcoside SN-135W etc. are mentioned, for example.
The amount of the preservative added is, for example, 0.0001 to 0.1, preferably 0.0005 to 0.05, and more preferably 0.001 to 0.03 in terms of a weight ratio to the crosslinked resin (R).

Examples of the curing catalyst include amine compounds such as triethylamine, diethylethanolamine, and hexamethylenediamine; and organotin compounds such as dibutyltin dilaurate and dioctyltin dilaurate.
The addition amount of the curing catalyst is, for example, 0.0001 to 0.005, preferably 0.0001 to 0.001, and more preferably 0.00005 to 0.0005 as a weight ratio with respect to the crosslinked resin (R).

The application method of the intermediate layer forming coating liquid may be any application method, for example, a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, a curtain coating method, or the like. is there. Among these application methods, an optimum method can be selected in consideration of physical properties and productivity of the coating liquid. In particular, a dip coating method, a blade coating method and a spray coating method are suitable.
In order to stabilize the dispersibility of the coating liquid, an apparatus used for coating may be provided with a coating liquid dispersing apparatus represented by an ultrasonic generator.

  The dip coating method is a method of forming a layer on a conductive support by immersing the conductive support in a coating tank filled with a coating solution and then pulling it up at a constant speed or a speed that changes sequentially. Since this method is relatively simple and excellent in terms of productivity and cost, it is generally used when manufacturing a photoreceptor.

  The thermosetting treatment can be performed using a known apparatus such as a hot-air drying furnace and a far-infrared drying furnace, and the conditions include the type and blending ratio of the aqueous block isocyanate compound to be used and the aqueous resin having an active hydrogen-containing group. The temperature may be set as appropriate, and is usually 110 to 150 ° C., preferably 130 to 150 ° C., for 10 minutes to 1 hour.

  The film thickness of the intermediate layer (total film thickness when formed as a plurality of layers) is not particularly limited, but is preferably 0.1 to 20 μm, and particularly preferably 0.5 to 10 μm. If the thickness of the intermediate layer is less than 0.1 μm, it may not be possible to obtain uniform surface properties by covering defects of the conductive support, and carrier injection from the conductive support can be prevented. In some cases, the chargeability is lowered and the intermediate layer does not function substantially. On the other hand, when the film thickness of the intermediate layer exceeds 20 μm, it is difficult to form a uniform coating film, and the sensitivity of the photoreceptor may be lowered.

The intermediate layer in the photoreceptor of the present invention may be a single layer or a plurality of layers.
As the intermediate layer of a plurality of layers, for example, a first intermediate layer (conductive layer) containing conductive inorganic oxide fine particles (for example, a film thickness of 2 to 20 μm) and a second intermediate layer not containing inorganic oxide fine particles ( Insulating layer) (for example, a film thickness of 0.2 to 1 μm), a first intermediate layer (insulating layer or blocking layer) that does not contain inorganic oxide fine particles (for example, a film thickness of 0.2 to 1 μm) and its Examples thereof include a combination with a second intermediate layer (moire prevention layer) (for example, a film thickness of 3 to 10 μm) containing conductive inorganic oxide fine particles (for example, a particle diameter of 400 to 800 nm) for preventing moire on the upper portion.

(式中、Ａ、Ａｒ₁、Ａｒ₂及びＺは上記と同義。詳細は下記で説明する。)
で示されるＮ,Ｎ'-ビスエナミン化合物を含有する限り、積層型感光層５であっても、単層型感光層５'であってもよい。 [Photosensitive layer]
The photosensitive layers 5 and 5 ′ have the general formula (1) as a charge transport material.

(Wherein, A, Ar _1, Ar ₂ and Z is as defined above. Details will be described below.)
As long as the N, N′-bisenamine compound represented by the formula (1) is contained, it may be a multilayer photosensitive layer 5 or a single-layer photosensitive layer 5 ′.

The bisenamine compound represented by the general formula (1) has a high charge mobility. By including a bisenamine compound having a high charge mobility as a charge transport material in the photosensitive layer, an electrophotographic photoreceptor exhibiting high responsiveness even in a low temperature and low humidity environment can be obtained.
Therefore, even when the photoconductor is downsized and used in a high-speed electrophotographic process, it is possible to provide a high-quality image in various environments such as a low-temperature and low-humidity environment.
In addition, by using such a photoconductor, a highly reliable image forming apparatus that can provide a high-quality image in various environments such as a low-temperature and low-humidity environment with a small size and high image forming speed is realized. can do.

In the above formula (1),
A represents an arylene group which may have a substituent, a divalent heterocyclic group which may have a substituent, an alkylene group which may have a substituent, or a group —Ar ₃ —W—Ar _4. -(Wherein Ar ₃ and Ar ₄ are each independently an arylene group which may have a substituent or a divalent heterocyclic group which may have a substituent, and W is a bond, A cycloalkylidene group which may have a substituent or a divalent chain hydrocarbon group which may have a substituent.

Examples of the arylene group of A include o-phenylene, m-phenylene, p-phenylene, 1,4-naphthylene, 1,5-naphthylene, 2,6-naphthylene, 9,10-anthracenylene, and fluorinylene. it can.
The arylene group of A may optionally have one or more substituents. Examples of the substituent include, for example, a linear or branched alkyl group having 1 to 4 carbon atoms (which may be further substituted with one or more halogen atoms or a linear or branched alkyl group having 1 to 4 carbon atoms. A linear or branched alkoxy group having 1 to 4 carbon atoms (which may be further substituted with one or more halogen atoms or a linear or branched alkyl group having 1 to 4 carbon atoms), A linear or branched alkylthio group having 1 to 4 carbon atoms (which may be further substituted with one or more halogen atoms or a linear or branched alkyl group having 1 to 4 carbon atoms), a phenyl group ( This further includes one or more halogen atoms, a linear or branched alkyl group having 1 to 4 carbon atoms, a linear or branched alkoxy group having 1 to 4 carbon atoms, or a linear or branched chain having 1 to 4 carbon atoms. Optionally substituted with a branched alkylthio group), halogen Although atoms (preferably fluorine atoms) are exemplified without limitation.

  Specific examples of the substituent include methyl group, ethyl group, n-propyl group, methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, methylthio group, ethylthio group, n-propylthio, iso-propylthio, mono -, Di- or trifluoromethyl group, and phenyl group are exemplified, and methyl group, ethyl group, methoxy group, ethoxy group, methylthio group, ethylthio group, trifluoromethyl group, and phenyl group are preferable.

  Examples of the divalent heterocyclic group represented by A include divalent heterocyclic groups such as furylene, thienylene, pyrrolylene, benzofurylene, benzothienylene, indolylene, and carbazolylene. The divalent heterocyclic group of A may optionally have one or more substituents. The substituent is the same as the arylene group.

The alkylene group of A is, for example, a C _{1 to} C ₁₂ (preferably C _{1 to} C ₈ ) alkylene group, and examples thereof include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group. Can be mentioned. The alkylene group of A may optionally have one or more substituents. Examples of the substituent include, for example, a linear or branched alkyl group having 1 to 4 carbon atoms (which may be further substituted with one or more halogen atoms or a linear or branched alkyl group having 1 to 4 carbon atoms. A linear or branched alkoxy group having 1 to 4 carbon atoms (which may be further substituted with one or more halogen atoms or a linear or branched alkyl group having 1 to 4 carbon atoms), A linear or branched alkylthio group having 1 to 4 carbon atoms (which may be further substituted with one or more halogen atoms or a linear or branched alkyl group having 1 to 4 carbon atoms), a halogen atom ( Preferred are fluorine atoms), but are not limited thereto.

  Specific examples of the substituent include methyl group, ethyl group, n-propyl group, methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, methylthio group, ethylthio group, n-propylthio, iso-propylthio, mono -, Di-, or trifluoromethyl groups are exemplified, and a methyl group, ethyl group, methoxy group, ethoxy group, methylthio group, ethylthio group, and trifluoromethyl group are preferred.

Ar ₃ and Ar ₄ may be the same or different in the group —Ar ₃ —W—Ar ₄ —.
Examples of the arylene group of Ar ₃ and Ar ₄ include m-phenylene, p-phenylene, 1,4-naphthylene, 1,5-naphthylene, and 2,6-naphthylene. Arylene groups of Ar ₃ and Ar ₄ may optionally have one or more substituents. The substituent is the same as the arylene group of A.

Examples of the divalent heterocyclic group represented by Ar ₃ and Ar ₄ include divalent heterocyclic groups such as furylene, thienylene, pyrrolylene, benzofurylene, benzothienylene, indoleylene, and carbazolylene. Ar ₃ and Ar ₄ divalent heterocyclic groups may optionally have one or more substituents. The substituent is the same as the arylene group of A.

The cycloalkylidene group of W is, for example, a C _{3 to} C ₈ cycloalkylidene group, and examples thereof include a cyclopentylidene group, a cyclohexylidene group, and a cycloheptylidene group. The cycloalkylidene group of W may optionally have one or more substituents. The substituent is the same as the alkylene group of A.

Examples of the divalent chain hydrocarbon group for W include C ₁ -C ₄ (preferably C ₁ -C ₃ ) divalent chain hydrocarbon groups, which are saturated hydrocarbon groups. Or, if possible, it may be an unsaturated hydrocarbon group. More specific examples include a methylene group, an ethylene group, and a vinylene group. The bivalent chain hydrocarbon group of W may optionally have one or more substituents. The substituent is the same as the alkylene group of A.
W can be a bond.

  Specific examples of A include p-phenylene, 2,5-dimethyl-p-phenylene, m-phenylene, o-phenylene, 1,5-naphthylene, 1,4-naphthylene, 2,6-naphthylene, biphenylene, 3 3,3'-dimethyl-4,4'-biphenylene, 3,3'-diethyl-4,4'-biphenylene, 3,3'-dimethoxy-4,4'-biphenylene, 3,3'-dimethylthio-4, 4'-biphenylene, 4,4'-dimethoxy-3,3'-biphenylene, 9,10-anthracenylene, 3,3'-dimethyl-4,4'-stilbenylene, 2-p-phenylene-benzofuran-5-yl 2-p-phenylene-benzothiophen-5-yl, 2-p-phenylene-N-methylindol-5-yl, 2,7- (N-methylcarbazole) lene, 4,4'-stilbenylene, hexamethylene ,

等が挙げられる。

Etc.

Ar ₁ may have an aryl group which may have a substituent, a monovalent heterocyclic group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. A heterocyclic alkyl group is shown.

Examples of the aryl group for Ar ₁ include phenyl, naphthyl, and pyrenyl. Of these, phenyl and naphthyl are preferable. The aryl group of Ar ₁ may optionally have one or more substituents. The substituent is the same as the arylene group of A.
Examples of the monovalent heterocyclic group for Ar ₁ include furyl, thienyl, thiazolyl, benzofuryl, benzothienyl, benzothiazolyl, oxazolyl, benzoxazolyl, and carbazolyl. Ar ₁ monovalent heterocyclic group optionally has one or more substituents. The substituent is the same as the arylene group of A.

Examples of the aralkyl group for Ar ₁ include an aralkyl group in which the alkyl portion is, for example, C _{1 to} C ₆ (preferably C _{1 to} C ₄ , more preferably C _{1 to} C ₂ ) alkyl, and more specifically. Can include benzyl and phenethyl. The Ar ₁ aralkyl group may optionally have one or more substituents. The substituent is the same as the arylene group of A for the aryl moiety, and the same as the alkylene group of A for the alkyl moiety.

Examples of the heterocyclic alkyl group for Ar ₁ include a heterocyclic alkyl group in which the alkyl portion is, for example, C _{1 to} C ₆ (preferably C _{1 to} C ₄ , more preferably C _{1 to} C ₂ ) alkyl, More specifically, thienylmethyl can be mentioned. The heterocyclic alkyl group for Ar ₁ may optionally have one or more substituents. The substituent is the same as the arylene group of A for the heterocyclic portion and the same as the alkylene group of A for the alkyl portion.

Specific examples of Ar ₁ include phenyl, o-tolyl, m-tolyl, p-tolyl, 2,4-xylyl, 3,4-xylyl, 3,5-xylyl, p-methoxyphenyl, p-methylthiophenyl, Mention may be made of 3-methyl-4-methoxyphenyl, naphthyl, biphenyl, benzofuryl, benzothiazolyl, benzoxazolyl, N-ethylcarbazolyl, benzyl, methylbenzyl, methoxybenzyl, 2-thienylmethyl.

Ar ₂ represents an aryl group which may have a substituent or a divalent heterocyclic group which may have a substituent.
Examples of the arylene group for Ar ₂ include phenylene and naphthylene.
Examples of the divalent heterocyclic group represented by Ar ₂ include pyridine, furan, and thiophene.

Z represents an atomic group necessary for forming a ring together with Ar ₂ , for example, an ether (—O—), thioether (—S—), amino (—NH—) or silyl (—SiH ₂ —) bond. May be an alkylene group (preferably C _{2 to} C ₄ ) which may be contained in the chain or may be present at the terminal. Specific examples of Z include ethylene - (CH _{2) 2} -, trimethylene - (CH _{2) 3} -, tetramethylene - (CH _{2) 4} -, ethyleneoxy - (CH _{2) 2} -O-, ethylenethiourea - ( CH ₂ ) ₂ —S—, ethyleneamino- (CH ₂ ) ₂ —NH—, and ethylenesilyl- (CH ₂ ) ₂ —SiH ₂ —.

Partial structure formed by Ar ₂ and Z together (ring structure)

Is, for example, a monocyclic or polycyclic carbocyclic or heterocyclic ring, and examples include a structure in which a condensed ring is formed by a benzene ring-cyclohexane ring, a structure in which a condensed ring is formed by a furan ring-cyclohexane ring, A structure that forms a condensed ring with a thiophene ring-cyclohexane ring, a structure that forms a condensed ring with a naphthalene ring-cyclohexane ring, a structure that forms a condensed ring with a benzene ring-cyclopentane ring, and a condensed ring with a benzene ring-cycloheptane ring Structure to form, Structure to form condensed ring with pyridine ring-cyclohexane ring, Structure to form condensed ring with benzene ring-spirobicyclohexane ring, Structure to form condensed ring with benzene ring-piperidine ring, benzene ring-tetrahydropyran And a structure in which a condensed ring is formed by benzene ring-tetrahydrothiapyran.
The ring structure represented by the above formula may optionally have one or more substituents. The substituent is the same as the arylene group of A.

が挙げられる。 As a specific example,

Is mentioned.

Of the N, N′-bisenamine compounds represented by the general formula (1), A is 2,5-dimethyl-p-phenylene, 3,3′-dimethylbiphenylene or 3,3′-dimethoxybiphenylene, Ar ₁ is an m-tolyl group, 2,4-xylyl group, or 3,4-xylyl group, and (—Ar ₂ —Z —) = — is a structure in which a condensed ring is formed by a benzene ring-cyclohexane ring. Listed as a particularly excellent compound from the viewpoints of electrophotographic properties, cost, and production

  Specific examples of the N, N′-bisenamine compound represented by the general formula (1) are shown in Table 1. However, the bisenamine compound represented by the general formula (1) is not limited to the exemplified compounds described in Table 1.

  The bisenamine compound represented by the general formula (1) can be synthesized by various methods, for example, by the following synthesis process. That is, the N, N′-disubstituted amine compound represented by the following formula (II) and 2 equivalents of the aldehyde derivative represented by the following formula (III) are heated in a solvent such as benzene and subjected to dehydration condensation. A bisenamine compound (I) represented by 1) is obtained.

<Laminated photosensitive layer>
The laminated photosensitive layer is composed of a charge generation layer and a charge transport layer. 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.
When the photosensitive layer is a laminate type, the charge transport layer contains an N, N′-bisenamine compound represented by the general formula (1) as a charge transport material.
The charge generation layer and the charge transport layer may be formed on the intermediate layer in this order or in the reverse order, but are preferably formed in this order.

(Charge transport layer)
The charge transport layer contains, as main components, a charge transport material having a capacity to accept and transport charges generated by the charge generation material in the charge generation layer and a binder resin (binder).
In the present invention, the charge transport layer contains one or more bisenamine compounds represented by the general formula (1) as a charge transport material. The charge transport layer may contain one or more charge transport materials other than the bisenamine compound represented by the general formula (1). Preferably, the bisenamine compound represented by the general formula (1) is charged. It is contained as a main component of the charge transport material in the transport layer. Here, the “main component” means 50% by weight or more.

  Other charge transport materials that can be combined with the bisenamine compound represented by the general formula (1) include, for example, styryl compounds (for example, β-phenyl- [4- (dibenzylamino)] stilbene, β-phenyl- [4- ( N-ethyl-N-phenylamino)] stilbene, 1,1-bis (4-diethylaminophenyl) -4,4-diphenylbutadiene), hydrazone compounds (eg 4- (dibenzylamino) benzaldehyde-N, N-diphenyl Hydrazone, 4- (ethylphenylamino) benzaldehyde-N, N-diphenylhydrazone, 3,3-bis [(4′-diethylamino) phenyl] acrolein-N, N-diphenylhydrazone) or a triphenylamine compound (for example 4- Methoxy-4 ′-(4-methoxystyryl) triphenylamine, 4-methoxy-4′-styryltriphenylamine) and the like.

As the binder resin, a resin having binding properties 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 the polymer (vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, acryloni Insulating resin such as tolyl-styrene copolymer resin). These binder resins can be used alone or in combination of two or more.

Among them, polycarbonate-based resins, polyarylate resins, and polystyrene resins are photochemically stable, have excellent compatibility with charge transport materials, and have a volume resistance of 10 ¹³ Ω or more and electrical insulation. It is preferable because it is excellent and has excellent film formability and potential characteristics.

  The ratio E / B between the weight E of the charge transport material and the weight B of the binder resin is usually 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 becomes high, and sufficient sensitivity may not be obtained. On the other hand, when the ratio E / B exceeds 10/12, the printing durability of the charge transport layer and the durability of the photoreceptor may be lowered.

The charge transport layer may be a chemical sensitizer, an optical sensitizer, an antioxidant, an ultraviolet absorber, a dispersion stabilizer, a sensitizer, a leveling agent, or a plasticizer as long as the effect of the present invention is not impaired. One or two or more additives selected from fine particles of inorganic compounds or organic compounds may be contained.
These additives may be contained in the charge generation layer described later, or may be contained in both the charge transport layer and the charge generation 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, and 4-nitrobenzaldehyde. Aldehydes such as: 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 And those obtained by polymerizing these electron-withdrawing materials.

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

Antioxidants can maintain sensitivity stability over a long period of time.
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, and the like. These may be used alone or in combination of two or more. Can be used.

The addition amount of the antioxidant is preferably 0.1 to 40 parts by weight, particularly preferably 0.5 to 15 parts by weight, based on 100 parts by weight of the charge transport material.
If the addition amount of the antioxidant is less than 0.1 part by weight, sufficient effects may not be obtained for improving the stability of the coating liquid 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.

A leveling agent and a plasticizer 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.
The fine particles of an inorganic compound or an organic compound can increase mechanical strength and improve electrical characteristics. Examples of such fine particles include the fine particles described above for the intermediate layer.

  The charge transport layer is prepared by dissolving or dispersing a charge transport material, a binder resin and, if necessary, the above-mentioned additives in a suitable organic solvent to prepare a charge transport layer forming coating solution. It can be formed by coating on the surface of the charge generation layer or intermediate layer (in the case of reverse bilayer type) and then drying to remove the organic solvent. More specifically, for example, a charge transport layer forming coating solution is prepared by dissolving or dispersing a charge transport material and, if necessary, an additive in a resin solution obtained by dissolving a binder resin in an organic solvent. .

  Examples of the organic solvent include aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, tetralin, diphenylmethane, dimethoxybenzene, and dichlorobenzene; halogenated hydrocarbons such as dichloromethane, dichloroethane, and tetrachloropropane; tetrahydrofuran (THF) , Ethers such as dioxane, dibenzyl ether, dimethoxymethyl ether, 1,2-dimethoxyethane; ketones such as methyl ethyl ketone, cyclohexanone, acetophenone, isophorone; esters such as methyl benzoate, ethyl acetate, butyl acetate, diphenyl sulfide Sulfur-containing solvents such as: Fluorinated 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 transport material may be pre-ground.
The preliminary pulverization can be performed using a general pulverizer such as a ball mill, a sand mill, an attritor, a vibration mill, or an ultrasonic disperser.

  The constituent materials can be dissolved or dispersed in the resin solution using, for example, a general dispersing machine 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 liquid for forming the charge transport layer is a bakery 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 in the case of a drum. Examples thereof include a ring method and a dip coating method.

  The temperature in the drying step of the coating film is not particularly limited as long as it is a temperature at which the used organic solvent can be removed, and there is no problem with natural drying, but 50 to 140 ° C. is appropriate from the viewpoint of drying time, and 80 to 130 ° C is particularly preferred. If the drying temperature exceeds 140 ° C., the electrical characteristics during repeated use of the photoreceptor may deteriorate and the resulting image may deteriorate.

  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, the sharpness is reduced and the residual potential is increased. Image degradation may occur significantly.

(Charge generation layer)
The charge generation layer contains, as a main component, a charge generation material having a charge generation capability of generating charges by absorbing irradiated light, and optionally contains a binder resin (binder) and / or an additive. Also good.

  Specific examples of the charge generating substance include azo pigments (carbazole skeleton, styryl stilbene skeleton, triphenylamine skeleton, dibenzothiophene skeleton, oxadiazole skeleton, fluorenone skeleton, bis-stilbene skeleton, distyryl oxadiazole skeleton or distyryl. Monoazo pigments, bisazo pigments, trisazo pigments, etc.), perylene pigments (peryleneimide, perylene anhydride, etc.), polycyclic quinone pigments (quinacridone, anthraquinone, pyrenequinone, etc.), phthalocyanine pigments (having a carbazole skeleton) (Metal phthalocyanine, metal-free phthalocyanine, halogenated metal-free phthalocyanine, etc.), indigo pigments (indigo, thioindigo, etc.), squarylium dyes, azurenium dyes, thiopyrylium dyes, pyrylium salts, triphenylmeta And organic pigments or dyes such as organic pigments, and inorganic materials such as selenium and amorphous silicon.

Among these, phthalocyanine pigments, azo pigments, and perylene pigments are particularly preferable because they have high sensitivity.
The charge generation materials can be used alone or in combination of two or more.

  The charge generation layer may contain an appropriate amount of the additives described for the charge transport layer, if desired, within the range where the preferable characteristics of the present invention are not impaired.

The charge generation layer can be formed by a known dry method and wet method.
Examples of the dry method include a method in which a charge generating material is vacuum-deposited on the surface of an intermediate layer on a conductive support.
As the wet method, for example, a charge generation material, and optionally, an additive and / or a binder resin are dissolved or dispersed in an appropriate organic solvent to prepare a charge generation layer forming coating solution. Examples include a method of coating the surface of an intermediate layer or a charge transport layer (in the case of an inverted two-layer type) formed on a conductive support, and then drying to remove the organic solvent.

The use of a binder resin is preferable because it can improve the mechanical strength and durability of the charge generation layer, the binding property between layers, and the like.
As the binder resin, a resin having a binding property used in this field, for example, one or more of the binder resins described for the charge transport layer can be used.

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.
When 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 those that should be erased by exposure are reduced, and image fogging, particularly fogging of an image called black spots where toner adheres to a white background and minute black spots are formed may increase.

  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, when the film thickness of the charge generation layer exceeds 5 μm, charge transport inside the charge generation layer becomes a rate-determining step in the process of erasing charges on the surface of the photoreceptor, and the sensitivity may be lowered.

  Other processes and conditions are in accordance with the formation of the charge transport layer.

<Single layer type photosensitive layer>
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 additives such as those mentioned for the charge transport layer within the range that does not impair the effects of the present invention.

  A single-layer type photosensitive layer is prepared by dissolving and / or dispersing a charge generating substance, a charge transporting substance, a binder resin and, if necessary, an additive in an appropriate organic solvent to prepare a coating liquid for forming a single-layer type photosensitive layer. 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.

  The film thickness of the single-layer type photosensitive layer is not particularly limited, but is preferably 10 to 100 μm, particularly preferably 15 to 50 μm. 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.

  Other steps and conditions are in accordance with the formation of the charge transport layer.

[Protective layer]
Although not shown, the photoreceptor of the present invention may have a protective layer on the surface of the photosensitive layer.
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 formed by, for example, forming a protective layer by dissolving or dispersing a binder resin (for example, those mentioned for the charge transport layer) in an appropriate organic solvent, and additives such as an antioxidant and an ultraviolet absorber as necessary. It can be formed by preparing a coating solution, applying this coating solution for forming a protective layer on the surface of a single-layer type photosensitive layer or a laminated type photosensitive layer, and removing the organic solvent by drying.

  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. If the thickness of the surface protective layer 5 is less than 0.5 μm, the surface resistance of the photoreceptor is inferior and the durability may be insufficient. Conversely, if it exceeds 10 μm, the resolution of the photoreceptor decreases. There is.

  Other steps and conditions are in accordance with the formation of the charge transport layer.

Electrophotographic image forming apparatus The image forming apparatus of the present invention exposes the electrophotographic photoreceptor obtained by the production method of the present invention, charging means for charging the photoreceptor, and the charged photoreceptor. Exposure means for forming an electrostatic latent image, developing means for developing the electrostatic latent image to form a toner image, transfer means for transferring the toner image onto a recording material, and the transferred toner image At least a fixing unit that forms an image by fixing the toner image on the recording material, a cleaning unit that removes and collects toner remaining on the photoconductor, and a static elimination unit that neutralizes surface charge remaining on the photoconductor. Yes.
The image forming apparatus of the present invention can be various printers, copiers, facsimiles, multifunction peripherals, etc. using an electrophotographic process regardless of monochrome or color.

  The image forming apparatus of the present invention will be described with reference to the drawings. However, the image forming apparatus of the present invention is not limited to the following description, and can be obtained by the manufacturing method of the present invention described above as a photoreceptor. As long as the electrophotographic photosensitive member is provided, any other component can be adopted.

FIG. 2 is a schematic side view showing the configuration of an embodiment of the image forming apparatus of the present invention.
An image forming apparatus 20 in FIG. 2 includes a photoconductor 21 according to the present invention (for example, the photoconductor of any form shown in FIG. 1), a charging unit (charger) 24, an exposure unit 28, and a developing unit. The image forming apparatus includes a (developing unit) 25, a transfer unit (transfer unit) 26, a cleaning unit (cleaner) 27, and a fixing unit (fixing unit) 31. 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, thereby rotating the photoconductor 21 at a predetermined peripheral speed.

  A charger 24, exposure means 28, developing unit 25, transfer unit 26 and 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. In the drawing, the charger 24 is shown as a contact-type charging roller 24a, but it may be a charging brush or a charger wire such as a corotron or a scorotron. Reference numeral 24b indicates a bias power source.

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

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

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

  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 27a that peels off toner remaining on the outer peripheral surface of the photoconductor, and a cleaning blade. And a recovery casing 27b for storing the toner peeled off by 27a. The cleaner 27 can be provided together with a static elimination 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 provided to face the heating roller and pressed by the heating roller 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 unit, the photosensitive member 21 is sensitized by the charger 24 provided upstream in the rotational direction of the photosensitive member with respect to the imaging point of the exposure light 28a from the exposure unit 28. The surface of the body 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 the surface potential of the portion irradiated with the light is different from the surface potential of the portion not irradiated with the light. An electrostatic latent image is formed.

  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 downstream of the image forming point of the light 28a from the exposure unit 28 in the rotation direction of the photosensitive member 21. The latent image is developed to form a toner image.

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

  The transfer paper 30 to which the toner image has been transferred is conveyed to a fixing device 31 by a conveying means, and is heated and pressurized when passing through a contact portion between a heating roller 31a and a pressure roller 31b of the fixing device 31, and toner The 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 after the transfer of the toner image by the transfer unit 26 is separated from the surface of the photoconductor by the cleaner 27 and collected. The surface charge of the photoreceptor from which the toner has been removed in this way is removed by the light from the charge eliminating lamp, and the electrostatic latent image on the surface of the photoreceptor 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 the examples.

(Example 1)
As a conductive support, an aluminum cylindrical support having a diameter of 30 mm, a length of 300 mm, and a thickness of 0.8 mm was used to produce the photoreceptor shown in FIG.
First, the following components were added to 69 parts by weight of water and dispersed for 6 hours using a paint shaker to prepare a coating solution for forming an intermediate layer (total amount: 1 kg).

Aqueous blocked isocyanate compound (solid content: 40%, NCO content: 5.4%, manufactured by Mitsui Chemicals Polyurethanes, product name: Takenate WB-920) 4.2 parts by weight Aqueous resin having an active hydrogen-containing group As a polyacryl polyol (solid content: 45%, OH value: 80, manufactured by DIC Corporation, product name: Burnock WE-300) 8.4 parts by weight-Aluminum oxide (Al ₂ O ₃ ) as inorganic oxide fine particles And titanium dioxide fine particles surface-treated with zirconium dioxide (ZrO ₂ ) (number average primary particle size: minor axis 40-70 nm, major axis 200-300 nm, manufactured by Ishihara Sangyo Co., Ltd., product name: TTO-D -1) 12 parts by weight-Antifoaming agent (polyether foam inhibitor, manufactured by San Nopco, product name: SN deformer 470) 0.5 part by weight

  In the coating solution for forming an intermediate layer prepared as described above, the molar ratio of the isocyanate group (H) in the aqueous blocked isocyanate compound to the active hydrogen-containing group (B) in the aqueous resin having an active hydrogen-containing group (H / B) is 1.0, and the weight ratio (P / R) of the inorganic oxide fine particles (P) to the crosslinked resin (the total R of the aqueous blocked isocyanate compound and the aqueous resin having an active hydrogen-containing group) is 6/4. Met.

  The obtained coating solution for forming an intermediate layer is filled in a coating tank, the conductive support is dipped and then pulled up, and the obtained coating film is dried and cured at a temperature of 150 ° C. for 30 minutes to obtain a film thickness of 1. A 0 μm intermediate layer was formed.

Next, the following components were mixed with 97 parts by weight of methyl ethyl ketone, which is an organic solvent, and dispersed using a paint shaker to prepare a charge generation layer forming coating solution (total amount: 1 kg).
-2 parts by weight of Y-type oxotitanium phthalocyanine (manufactured by Sanyo Pigment Co., Ltd.) as a charge generating substance-1 part by weight of polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd., product name: ESREC BBM-S) as a binder resin

  The obtained charge generation layer forming coating solution was applied onto the previously formed intermediate layer by the same dip coating method as that for the intermediate layer, and naturally dried to form a charge generation layer having a thickness of 0.4 μm. .

Subsequently, the following components were dissolved in 110 parts by weight of tetrahydrofuran (THF) as an organic solvent to prepare a charge transport layer forming coating solution (total amount: 1 kg).
As a charge transport material, 10 parts by weight of a bisenamine compound shown as Exemplified Compound 1 in Table 1. As a binder resin, 18 parts by weight of a polycarbonate resin (product name: Iupilon Z400 manufactured by Mitsubishi Engineering Plastics Co., Ltd.) As an antioxidant 2,6-di-t-butyl-4-methylphenol 0.5 parts by weight As a leveling agent, dimethylpolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KF-96) 0.004 parts by weight

The obtained charge transport layer forming coating solution was applied on the charge generation layer formed earlier by the same dip coating method as that for the intermediate layer, and dried at a temperature of 130 ° C. for 1 hour to obtain a charge having a thickness of 23 μm. A transport layer was formed.
The photoreceptor of Example 1 was produced as described above.

(Examples 2 to 6)
Photoreceptors of Examples 2 to 6 are produced in the same manner as in Example 1 except that the bisenamine compounds of Exemplified Compounds 11, 14, 23, 27, and 48 are used in place of Exemplified Compound 1 as the charge transport material. did.

(Example 7)
A photoconductor of Example 7 was produced in the same manner as in Example 1 except that the following components were added to 67 parts by weight of water to prepare a coating solution for forming an intermediate layer (total amount: 1 kg).
-Aqueous block isocyanate compound (solid content: 42%, NCO content: 7.5, manufactured by Nippon Polyurethane Industry Co., Ltd., product name: BWD-102) 7.1 parts by weight-As an aqueous resin having an active hydrogen-containing group, Polyether polyol (solid content: 35%, OH value: 60, manufactured by Nippon Polyurethane Industry Co., Ltd., product name: AQD-473) 14.3 parts by weight ・ Titanium oxide fine particles (made by Ishihara Sangyo Co., Ltd.) as inorganic oxide fine particles Product name: TTO-D-1) 12 parts by weight Defoaming agent (polyether foam inhibitor, manufactured by San Nopco, product name: SN deformer 470) 0.5 part by weight

  In the intermediate layer-forming coating solution prepared as described above, the molar ratio (H / B) of isocyanate groups to active hydrogen-containing groups is 1.0, and the weight ratio of inorganic oxide fine particles to cross-linked resin (P / R) was 6/4.

(Example 8)
A photoconductor of Example 8 was produced in the same manner as in Example 1 except that the following components were added to 65 parts by weight of water to prepare a coating solution for forming an intermediate layer (total amount: 1 kg).
-Aqueous blocked isocyanate compound (solid content: 37.5%, NCO content: 3.7, manufactured by Sumika Bayer Urethane Co., Ltd., product name: Bihijoule VP LS 2310) 19.6 parts by weight-Has an active hydrogen-containing group As a water-based resin, polyvinyl acetal (solid content: 20%, OH value: 570, manufactured by Sekisui Chemical Co., Ltd., product name: KW-3) 3.2 parts by weight As inorganic oxide fine particles, titanium oxide fine particles (Ishihara Sangyo) Co., Ltd., product name: TTO-D-1) 12 parts by weight Defoaming agent (polyether foam inhibitor, manufactured by San Nopco, product name: SN deformer 470) 0.5 parts by weight

  In the intermediate layer-forming coating solution prepared as described above, the molar ratio (H / B) of isocyanate groups to active hydrogen-containing groups is 1.0, and the weight ratio of inorganic oxide fine particles to cross-linked resin (P / R) was 6/4.

Example 9
A photoconductor of Example 9 was produced in the same manner as in Example 1 except that the following components were added to 65 parts by weight of water to prepare a coating solution for forming an intermediate layer (total amount: 1 kg).
-Aqueous blocked isocyanate compound (solid content: 37.5%, NCO content: 3.7, manufactured by Sumika Bayer Urethane Co., Ltd., product name: Bihijoule VP LS 2310) 19.6 parts by weight-Has an active hydrogen-containing group As an aqueous resin, water-soluble cellulose (OH value: 360, manufactured by Shin-Etsu Chemical Co., Ltd., product name: Metrolose 65SH-400) 3.2 parts by weight ・ As inorganic oxide fine particles, zinc oxide fine particles (manufactured by Sakai Chemical Industry Co., Ltd.) Product name: STR-60) 12 parts by weight Defoaming agent (polyether foam inhibitor, manufactured by San Nopco, product name: SN deformer 470) 0.5 part by weight

  In the intermediate layer-forming coating solution prepared as described above, the molar ratio (H / B) of isocyanate groups to active hydrogen-containing groups is 1.0, and the weight ratio of inorganic oxide fine particles to cross-linked resin (P / R) was 6/4.

(Example 10)
A photoconductor of Example 10 was produced in the same manner as Example 1 except that the following components were added to 65 parts by weight of water to prepare a coating solution for forming an intermediate layer (total amount: 1 kg).
-Aqueous blocked isocyanate compound (solid content: 45%, NCO content: 7, manufactured by Mitsui Chemicals Polyurethanes, product name: Takenate WB-820) 13.8 parts by weight-As an aqueous resin having an active hydrogen-containing group, water-soluble Nylon (solid content: 20%, NH content: 10, manufactured by Nagase ChemteX Corporation, product name: Toresin FS-350) 8.8 parts by weight-Zinc oxide fine particles (Sakai Chemical Industry Co., Ltd.) as inorganic oxide fine particles Product made by company, product name: STR-60) 12 parts by weight Defoaming agent (polyether foam inhibitor, manufactured by San Nopco, product name: SN deformer 470) 0.5 part by weight

  In the intermediate layer-forming coating solution prepared as described above, the molar ratio (H / B) of isocyanate groups to active hydrogen-containing groups is 1.0, and the weight ratio of inorganic oxide fine particles to cross-linked resin (P / R) was 6/4.

Example 11
A photoconductor of Example 11 was produced in the same manner as in Example 1 except that the following components were added to 65 parts by weight of water to prepare a coating solution for forming an intermediate layer (total amount: 1 kg).
Aqueous blocked isocyanate compound (solid content: 40%, NCO content: 5.4%, manufactured by Mitsui Chemicals Polyurethanes, product name: Takenate WB-920) 4.2 parts by weight Aqueous resin having an active hydrogen-containing group 8.4 parts by weight of aqueous polyacrylic polyol (solid content: 45%, OH value: 80, manufactured by DIC Corporation, product name: Burnock WE-300) Company product, product name: S-2000) 12 parts by weight Defoaming agent (polyether foam inhibitor, manufactured by San Nopco, product name: SN deformer 470) 0.5 part by weight

  In the intermediate layer-forming coating solution prepared as described above, the molar ratio (H / B) of isocyanate groups to active hydrogen-containing groups is 1.0, and the weight ratio of inorganic oxide fine particles to cross-linked resin (P / R) was 6/4.

(Example 12)
A photoconductor of Example 12 was produced in the same manner as Example 1 except that the following components were added to 67 parts by weight of water to prepare a coating solution for forming an intermediate layer (total amount: 1 kg).
-Aqueous block isocyanate compound (solid content: 42%, NCO content: 7.5, manufactured by Nippon Polyurethane Industry Co., Ltd., product name: BWD-102) 7.1 parts by weight-As an aqueous resin having an active hydrogen-containing group, Polyether polyol (solid content: 35%, OH value: 60, manufactured by Nippon Polyurethane Industry Co., Ltd., product name: AQD-473) 14.3 parts by weight ・ Titanium oxide fine particles (made by Ishihara Sangyo Co., Ltd.) as inorganic oxide fine particles , Product name: TTO-D-1) 12 parts by weight Antifoaming agent (Polyether antifoaming agent, manufactured by San Nopco, product name: SN deformer 470) 0.5 part by weight

  In the coating liquid for forming an intermediate layer prepared as described above, the molar ratio (H / B) of isocyanate group to active hydrogen-containing group is 0.4, and the weight ratio of inorganic oxide fine particles to the crosslinked resin (P / R) was 6/4.

(Example 13)
A photoconductor of Example 13 was produced in the same manner as in Example 1 except that the following components were added to 67 parts by weight of water to prepare a coating solution for forming an intermediate layer (total amount: 1 kg).
-Aqueous block isocyanate compound (solid content: 42%, NCO content: 7.5, manufactured by Nippon Polyurethane Industry Co., Ltd., product name: BWD-102) 7.1 parts by weight-As an aqueous resin having an active hydrogen-containing group, Polyether polyol (solid content: 35%, OH value: 60, manufactured by Nippon Polyurethane Industry Co., Ltd., product name: AQD-473) 14.3 parts by weight ・ Titanium oxide fine particles (made by Ishihara Sangyo Co., Ltd.) as inorganic oxide fine particles Product name: TTO-D-1) 12 parts by weight Defoaming agent (polyether foam inhibitor, manufactured by San Nopco, product name: SN deformer 470) 0.5 part by weight

  In the coating solution for forming an intermediate layer prepared as described above, the molar ratio (H / B) of isocyanate group (H) to active hydrogen-containing group is 1.6, and the weight of inorganic oxide fine particles relative to the crosslinked resin The ratio (P / R) was 6/4.

(Example 14)
A photoconductor of Example 14 was produced in the same manner as in Example 1, except that the following components were added to 67 parts by weight of water to prepare a coating solution for forming an intermediate layer (total amount: 1 kg).
-Aqueous block isocyanate compound (solid content: 42%, NCO content: 7.5, manufactured by Nippon Polyurethane Industry Co., Ltd., product name: BWD-102) 7.1 parts by weight-As an aqueous resin having an active hydrogen-containing group, Polyether polyol (solid content: 35%, OH value: 60, manufactured by Nippon Polyurethane Industry Co., Ltd., product name: AQD-473) 14.3 parts by weight ・ Titanium oxide fine particles (made by Ishihara Sangyo Co., Ltd.) as inorganic oxide fine particles Product name: TTO-D-1) 12 parts by weight Defoaming agent (polyether foam inhibitor, manufactured by San Nopco, product name: SN deformer 470) 0.5 part by weight

  In the coating solution for forming an intermediate layer prepared as described above, the molar ratio (H / B) of the isocyanate group (H) to the active hydrogen-containing group is 0.7, and the weight of the inorganic oxide fine particles relative to the crosslinked resin The ratio (P / R) was 6/4.

(Example 15)
A photoconductor of Example 15 was produced in the same manner as Example 1, except that the following components were added to 67 parts by weight of water to prepare a coating solution for forming an intermediate layer (total amount: 1 kg).
-Aqueous block isocyanate compound (solid content: 42%, NCO content: 7.5, manufactured by Nippon Polyurethane Industry Co., Ltd., product name: BWD-102) 7.1 parts by weight-As an aqueous resin having an active hydrogen-containing group, Polyether polyol (solid content: 35%, OH value: 60, manufactured by Nippon Polyurethane Industry Co., Ltd., product name: AQD-473) 14.3 parts by weight ・ Titanium oxide fine particles (made by Ishihara Sangyo Co., Ltd.) as inorganic oxide fine particles Product name: TTO-D-1) 12 parts by weight Defoaming agent (polyether foam inhibitor, manufactured by San Nopco, product name: SN deformer 470) 0.5 part by weight

  In the intermediate layer forming coating solution prepared as described above, the molar ratio (H / B) of isocyanate groups to active hydrogen-containing groups is 1.3, and the weight ratio of inorganic oxide fine particles to the crosslinked resin (P / R) was 6/4.

(Comparative Example 1)
A photoconductor of Comparative Example 1 was prepared in the same manner as in Example 1 except that Compound C represented by Structural Formula (2) was used in place of Exemplified Compound 1 as the charge transport material (interlayer forming coating). In the working fluid, H / B = 1.0, P / R = 6/4).

(Comparative Example 2)
An electrophotographic photoreceptor of Comparative Example 2 was produced in the same manner as in Example 1 except that Compound E represented by Structural Formula (3) was used instead of the exemplified compound as the charge transport material (for forming an intermediate layer). In the coating solution, H / B = 1.0, P / R = 6/4).

(Comparative Example 3)
An intermediate layer without curing was formed using an intermediate layer forming coating solution (total amount 1 kg) prepared by adding the following components to a mixed organic solvent (50 parts by weight of methanol and 40 parts by weight of 1,3-dioxolane). A photoconductor of Comparative Example 3 was produced in the same manner as Example 1 except for the above.
-As a resin, copolymerized nylon (product name: Amilan CM8000, manufactured by Toray Industries, Inc.) 4 parts by weight-As inorganic oxide particles, titanium oxide particles (product name: TTO-D-1): 6 Parts by weight

(Comparative Example 4)
The following components: As inorganic oxide fine particles, zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd., product name: STR-60) 12 parts by weight. As resin, butyral resin (product name BM-1 manufactured by Sekisui Chemical Co., Ltd.); Solid) 3.7 parts by weight ・ Isocyanate compound (solid content: 65%, NCO content: 10.4%, manufactured by Sumitomo Bayer Urethane Co., Ltd., product name Desmodur E3265) 6.7 parts by weight to 78 parts by weight of methyl ethyl ketone In addition, dispersion treatment was carried out for 6 hours using a paint shaker to prepare a coating solution for forming an intermediate layer (total amount: 1 kg). An electrophotographic photoreceptor of Comparative Example 4 was produced in the same manner as Example 1 except that this coating solution was used.
In the intermediate layer-forming coating solution prepared as described above, the molar ratio (H / B) of the isocyanate group (H) in the isocyanate compound to the active hydrogen-containing group (B) in the resin having an active hydrogen-containing group. Was 1.0, and the weight ratio (P / R) of the inorganic oxide fine particles (P) to the cross-linked resin (the total R of the isocyanate compound and the resin having an active hydrogen-containing group) was 6/4.

[Evaluation]
(1) Electrical Characteristics and Environmental Stability of Photoreceptors Commercially available digital copying machines provided with a surface potential meter (Model: CATE751) for the photoreceptors of Examples 1 to 15 and Comparative Examples 1 to 4 (Sharp Co., Ltd., model: AR-F330) was mounted, and the surface potential in the image forming process was measured to evaluate the electrical characteristics and environmental stability of each photoconductor.

First, in a room temperature / normal humidity (N / N) environment at a temperature of 22 ° C. and a relative humidity of 65%, the surface potential of the photoreceptor immediately after the charging operation by the charger and immediately after the exposure by the laser beam (wavelength: 780 nm) (respectively, The charging potential V0 (V) and the residual potential VL (V)) were measured.
Similarly to the N / N environment, the ambient temperature / high humidity (N / H) environment at 25 ° C. and 85% relative humidity, and the normal temperature / low humidity (N / L) environment at 25 ° C. and 5% relative humidity. Residual potential VL (V) under the environment was measured, and the difference was 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 an N / N environment, a test image having a predetermined pattern (character test chart defined in ISO 19752) was continuously copied on 100,000 sheets of recording paper, and then immediately after the charging operation in the same manner as in the initial stage. The charging potential V0 (V) and the residual potential VL (V) were measured, and the difference from the initial residual potential was determined as a potential fluctuation ΔVLS (V) that is an index of fatigue characteristics.

  Further, after storing the intermediate layer forming coating solution used in the production of the photoconductors of Examples 1 to 15 and Comparative Examples 1 to 4 under an N / N environment for 3 months, a photoconductor was prepared in the same manner. The difference between the value when the residual potential VL [V] was measured under an N / N environment and the value of the initial residual potential VL was obtained as the potential fluctuation ΔVLP.

(2) Curing degree 0.5 g of the intermediate layer forming coating solution used in the production of the photoconductors of Examples 1 to 15 and Comparative Examples 1, 2, and 4 is 50 mm × 50 mm × 1.5 mm thick. A sample was obtained by uniformly coating the surface of the glass plate by a wire bar method and drying and curing the resulting coating film at a temperature of 150 ° C. for 30 minutes.
Each of the obtained samples was immersed in acetone at a temperature of 20 ° C. for 1 day while stirring at a rotation speed of 30 rpm, and the degree of cure (%) was determined by the following equation.
Curing degree (%) = (1− (weight before immersion−weight after immersion) / (weight before immersion)) × 100
Further, after the obtained sample was immersed in acetone for 3 months, the degree of cure (%) was determined in the same manner as described above.

(3) Image quality Quality evaluation of images formed using the photoreceptor was performed as follows.
A commercially available laser beam printer (Sharp Co., Ltd .: DM4501) using a laser as an exposure light source can be developed normally, and the amount of exposure to the photoreceptor and the rotational peripheral speed of the photoreceptor can be changed. Each of the photoreceptors of Examples 1 to 15 and Comparative Examples 1 to 4 was mounted.
By changing the rotational peripheral speed of the photoconductor, the time from the start of exposure to the end of development is adjusted to 50 milliseconds (50 msec), 90 milliseconds (msec), or 130 milliseconds (msec). Formed on recording paper.

The quality of the obtained image was evaluated by visual observation.
When no scumming was observed in the image, it was evaluated that the image quality was good.
Even when the occurrence of scumming was observed in the image, it was evaluated that the image quality was good when scumming was not recognized in the image formed again by increasing the exposure light amount.
In the re-formed image, if background smudge has occurred but the level is improved compared to before increasing the exposure light amount, the exposure light amount is increased until no improvement is observed. Quality (presence / absence of soil) was used as the evaluation result.
This evaluation is performed in a normal temperature and humidity environment at a temperature of 25 ° C. and a relative humidity of 55% (55% RH), and in a low temperature and low humidity (L / L) environment at a temperature of 5 ° C. and a relative humidity of 20% (20% RH). went.

(4) Printing durability The printing durability of the photoreceptor was evaluated as follows. The photoconductors of Examples 1 to 6 and Comparative Examples 1 and 2 were respectively mounted on a digital copying machine (manufactured by Sharp Corporation: MX-450) having a process speed of 117 mm / sec. After 40,000 images were formed, the film thickness d1 of the photosensitive layer was measured, and the difference between this value and the film thickness d0 of the photosensitive layer at the time of preparation was determined as a film reduction amount Δd (= d0−d1) An evaluation index for printing durability was used.

[result]
The evaluation results are shown in Table 2.

  As shown in Table 2, the photoconductors of Examples 1 to 15 have a smaller half-exposure amount (E1 / 2) and excellent sensitivity than the photoconductors of Comparative Examples 1 and 2. In addition, the photoconductors of Examples 1 to 15 are more responsive than the photoconductors of Comparative Examples 1 and 2, and when forming an image at a high speed or when forming an image in a low-temperature and low-humidity environment. It was confirmed that it provides high-quality images.

  Further, the photoconductors of the examples were compared with Comparative Example 3 of an organic solvent type using a polyamide-based resin that is widely used in current photoconductors, although water was used as a solvent for the coating solution. As a result, it was confirmed that the electrical characteristics, environmental stability, fatigue characteristics, coating solution stability, and image quality characteristics were equivalent or better.

  In addition, when the amount of the curing agent is small as in Example 12 (when H / B is less than 0.5), the degree of curing becomes low, so that the ratio of hydrophilic groups in the film increases, and environmental stability. It turns out that gets worse. On the contrary, when the amount of the curing agent is large as in Example 13 (when H / B exceeds 1.5), the environmental characteristics are not deteriorated so much, but the fatigue characteristics and the storage stability of the coating liquid are deteriorated. This is presumably because the remaining isocyanate groups that do not participate in the crosslinking reaction react with moisture to generate impurities that affect the electrical characteristics.

  In terms of printing durability, it was also found that the photoconductors of Examples 1 to 6 had a smaller film reduction amount Δd and higher printing durability than the photoconductors of Comparative Examples 1 and 2.

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Intermediate | middle layer 3 Charge generation layer 4 Charge transport layer 5 Laminated type photosensitive layer 5 'Single layer type photosensitive layer 20 Image forming apparatus 21 Photoconductor 22 Rotating axis of photoconductor 21 23 Rotation direction of photoconductor 21 Arrows to show 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 Exposure light 29 An arrow indicating the transfer direction of the transfer paper 30 30 Transfer paper 31 Fixing means (fixing device)
31a Heating roller 31b Pressure roller

Claims (6)

Having at least an intermediate layer and a photosensitive layer in this order on a conductive support;
For forming an intermediate layer, in which the intermediate layer is formed by dissolving or dispersing an aqueous resin having at least two aqueous hydrogenated groups capable of reacting with an aqueous blocked isocyanate compound and an isocyanate group in an aqueous medium on the conductive support. Obtained by applying a coating solution and then thermosetting.
The photosensitive layer as a charge transport material has the following general formula (1)

(In the formula, A represents an arylene group which may have a substituent, a divalent heterocyclic group which may have a substituent, an alkylene group which may have a substituent, or a group —Ar ₃ — W—Ar ₄ — (wherein Ar ₃ and Ar ₄ are each independently an arylene group which may have a substituent or a divalent heterocyclic group which may have a substituent; A bond, a cycloalkylidene group that may have a substituent, or a divalent chain hydrocarbon group that may have a substituent), and Ar ₁ may have a substituent An aryl group, a monovalent heterocyclic group that may have a substituent, an aralkyl group that may have a substituent, or a heterocyclic alkyl group that may have a substituent, Ar ₂ is a substituted group An aryl group which may have a group or a divalent heterocyclic group, and Z represents an atomic group necessary for forming a ring together with Ar _2. )
An electrophotographic photoreceptor comprising an N, N′-bisenamine compound represented by the formula:   The photoreceptor according to claim 1, wherein the intermediate layer further comprises inorganic oxide fine particles.   The photoreceptor according to claim 2, wherein the inorganic oxide fine particles are fine particles of titanium oxide or zinc oxide.   The photoconductor according to claim 1, wherein the aqueous resin is selected from a polyol compound resin, a polyvinyl acetal resin, and a polyamide compound resin.   In the intermediate layer forming coating solution, the molar ratio of the block isocyanate group (H) in the aqueous blocked isocyanate compound to the active hydrogen-containing group (B) in the aqueous resin is 0.5 or more and 1.5 or less. The photoconductor according to claim 1.   An electrostatic latent image obtained by subjecting the electrophotographic photosensitive member according to any one of claims 1 to 5, a charging unit for charging the electrophotographic photosensitive member, and exposure to the charged electrophotographic photosensitive member. An exposure means for forming the toner, a developing means for developing the electrostatic latent image to form a toner image, a transfer means for transferring the toner image onto the recording material, and the transferred toner image on the recording material. At least a fixing unit that forms an image by fixing the toner onto the electrophotographic photosensitive member, a cleaning unit that removes and collects toner remaining on the electrophotographic photosensitive member, and a neutralizing unit that neutralizes surface charge remaining on the electrophotographic photosensitive member. An image forming apparatus.

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