JP2010164945A - Electrophotographic photosensitive member and image forming device equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable electrophotographic photosensitive member reducing a load in environment in a photosensitive member manufacturing process, achieving high stability in production, preventing the occurrence of fluctuation of sensitivity depending on environment, and providing a high quality image without defect in image such as memory image, and also to provide an image forming device equipped with it. <P>SOLUTION: In this electrophotographic photosensitive member, an intermediate layer is provided between an electrical conductive support body and a photosensitive layer and is formed after it is heat hardened from a coating liquid for the intermediate layer including a block isocyanate compound, a resin having two groups containing active hydrogen reacting with isocyanate group in the block isocyanate compound or more, inorganic oxide particulates, and an aqueous medium. The photosensitive layer is a monolayer photosensitive layer containing at least an electric charge generating substance and an electric charge transport substance or a laminated photosensitive layer constituted by laminating an electric charge generating layer containing the electric charge generating substance and an electric charge transport layer containing the electric charge transport substance in this order or in the reverse order. The electric charge generating substance is oxotitanium phthalocyanine having a crystal structure. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrophotographic film comprising an intermediate layer formed from an intermediate layer coating solution containing water as a solvent, and a photosensitive layer containing oxotitanium phthalocyanine having a crystal structure and extremely high sensitivity as a charge generation material. The present invention relates to a photoreceptor and an image forming apparatus including the same.

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

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

An intermediate | middle layer is divided roughly into what consists of resin independent, and what consists of resin containing the pigment.
Examples of the resin used for the intermediate layer include water-soluble resins such as polyvinyl alcohol and casein, alcohol-soluble resins such as copolymer nylon resins, polyurethane, melamine resins, phenol resins, alkyd resins, epoxy resins, and siloxane resins. Examples thereof include a thermosetting resin that forms a network structure.

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

  However, resins such as melamine resin, phenol resin and methoxymethylated nylon are said to be one of the causative substances of sick house syndrome at the time of resin production, and a large amount of formaldehyde currently listed as a target substance in the Air Pollution Control Law is used. . Therefore, there is a problem that unreacted substances during production are occluded in the resin, and formaldehyde is generated in the process of thermal crosslinking after the formation of the intermediate layer of the photoreceptor. In order to prevent the release of the generated formaldehyde into the atmosphere, a recovery facility is necessary, and it is obviously expensive to introduce the facility.

In addition, for example, in the urethane resin disclosed in Japanese Patent No. 2790380 (Patent Document 1), an active hydrogen-containing group such as a polyol compound and an isocyanate group of an isocyanate compound that is a curing agent have a three-dimensional network crosslinking reaction. No formaldehyde is generated since a cured film is formed. However, since the reactivity of the isocyanate group is very high, there is a problem that the pot life of the coating liquid using these is very short.
Therefore, a method using a blocked isocyanate compound in which an isocyanate group is protected with a blocking agent such as oxime has been reported, and the pot life of a coating liquid using an organic solvent has been considerably improved (for example, JP-A-2005-115351). Publication (refer patent document 2)).

On the other hand, a highly sensitive oxotitanium phthalocyanine has recently been found as a charge generating material used in the photosensitive layer, and oxotitanium phthalocyanine having a crystalline form (also referred to as “crystalline oxotitanium phthalocyanine”) is used for light in a long wavelength range. Have been reported to exhibit particularly high sensitivity.
Crystalline oxotitanium phthalocyanine is known to be classified into a number of crystal types based on the difference in diffraction angle of the X-ray diffraction spectrum (for example, Moto Miyazaki, “Digital Imaging Technology-Photoconductor”, Electrophotographic Society of Japan). Journal, 1993, Vol. 32, No. 3, p. 282-289).
Examples of such crystal types include α type, A type, C type, Y type, M type, M-α type, I type, Phase I type, and Phase II type.

  Further, in the structural analysis of crystalline oxotitanium phthalocyanine, it has been found from its lattice constant that Phase II type belongs to the triclinic system, and Phase I type and C type belong to the monoclinic system. When the above crystal types are analyzed from these known lattice constants, it can be seen that the A type and the I type belong to the Phase I type, the α and B types belong to the Phase II type, and the M type belongs to the C type.

  As crystalline oxotitanium phthalocyanine, for example, Japanese Patent Publication No. 7-91486 (Patent Document 3) shows a maximum diffraction peak at a Bragg angle 2θ (2θ ± 0.2 °) of 27.3 ° in an X-ray diffraction spectrum. , 7.4 °, 9.7 °, and crystalline oxotitanium phthalocyanine having diffraction peaks at 24.2 °, Japanese Patent No. 2700859 (Patent Document 4), Bragg angle 2θ (2θ ± 0.2 °) Crystalline oxotitanium phthalocyanine having major diffraction peaks at 9.5 °, 9.7 °, 11.7 °, 15.0 °, 23.5 °, 24.1 ° and 27.3 °, Japanese Patent No. 128973 (Patent Document 5) discloses crystalline oxotitania having major diffraction peaks at Bragg angles 2θ (2θ ± 0.2 °) of 9.0 °, 14.2 °, 23.9 ° and 27.1 °. Photoreceptors using phthalocyanine is described.

In Japanese Patent No. 3569422 (Patent Document 6), an X-ray diffraction spectrum has a maximum diffraction peak at a Bragg angle 2θ (2θ ± 0.2 °) of 9.4 °, at least 7.3 °, 9 Crystals showing diffraction peaks at .7 ° and 27.3 °, and having clear branching peaks at 9.4 ° and 9.7 °, both of which are larger than the diffraction peak at 27.3 °. Oxotitanium phthalocyanine is described, and a photoconductor using the oxotitanium phthalocyanine is particularly sensitive to light in a long wavelength region, and is described to have good stability of characteristics in repeated use. .
Furthermore, in Japanese Patent Laid-Open No. 5-9402 (Patent Document 7), in the X-ray diffraction spectrum, Bragg angle 2θ (2θ ± 0.2 °) 7.6 °, 12.6 °, 16.3 °, 22 Crystalline (α-type) oxotitanium phthalocyanine that exhibits major diffraction peaks at .5 °, 25.3 °, and 28.6 ° is described. On the other hand, it is described that the sensitivity is particularly high and the stability of characteristics in repeated use is good.

  However, since these crystalline oxotitanium phthalocyanines are extremely sensitive, the number of carriers is large, and after holes are injected, electrons tend to stay in the charge generation layer, causing potential fluctuations as a kind of memory. There is a drawback that it is easy. This is particularly remarkable in the case of a photoconductor provided with an intermediate layer. In an environment such as low temperature and low humidity, the volume resistance against electrons of the charge generation layer and the intermediate layer increases, and such potential fluctuations increase. Such potential fluctuation, that is, electron retention, appears as a memory phenomenon for an actual image. In particular, when electrons stay at the interface between the charge generation layer and the intermediate layer, it appears as an increase in the bright portion potential during printing. Also, when used in the reversal development system, the sensitivity of the area exposed to light during the previous printing becomes slow, and if the entire black image is taken during the next printing, the previous printed part will appear white, so-called negative memory phenomenon Appears prominently.

  Therefore, as one means for reducing potential fluctuation, which is a major drawback of a photoreceptor using oxotitanium phthalocyanine in the charge generation layer, for example, JP-A-6-208238 (Patent Document 8) discloses an extremely A technique in which a conductive filler having fine particles and good dispersibility is contained in is reported. However, the carrier generation amount of oxotitanium phthalocyanine is so large that the retention of electrons in the charge generation layer cannot be completely eliminated, and the potential characteristics and image characteristics are considerably improved. I need.

Japanese Patent No. 2790380 JP-A-2005-115351 Japanese Examined Patent Publication No. 7-91486 Japanese Patent No. 2700859 Japanese Patent Laid-Open No. 3-128973 Japanese Patent No. 3569422 JP-A-5-9402 JP-A-6-208238 Moto Miyazaki, “Digital Imaging Technology-Photoconductor”, Journal of Electrophotographic Society, 1993, Vol. 32, No. 3, p. 282-289

  The present invention reduces the environmental load in the photoreceptor manufacturing process, has high production stability, has little fluctuation in sensitivity due to the environment, and can provide a high-quality image free from image defects such as memory images. It is an object of the present invention to provide a high electrophotographic photosensitive member and an image forming apparatus including the same.

The inventors of the present invention have used a photosensitive material that does not generate a volatile organic compound (VOC) and that has the lowest environmental load as a solvent and that has no danger of fire, and that has excellent liquid property over time in production. The intermediate layer formed using the intermediate layer coating solution and the photosensitive layer containing oxotitanium phthalocyanine having a crystal structure as a charge generation material solves the above problems and has excellent repeatability and environmental stability. The present inventors have found that a photoreceptor and an image forming apparatus provided with the photoreceptor can be provided, and have completed the present invention.
In order to realize an intermediate layer coating solution using water as a solvent as described above, the present inventors have prepared a blocked isocyanate compound, a resin having an active hydrogen-containing group capable of reacting with an isocyanate group, and inorganic oxide fine particles. And an intermediate layer coating solution containing an aqueous medium, combined with an intermediate layer formed using this, and a photosensitive layer containing oxotitanium phthalocyanine having a crystal structure as a charge generating substance.

Thus, according to the present invention, an intermediate layer is provided between the conductive support and the photosensitive layer,
Intermediate layer coating wherein the intermediate layer comprises a blocked isocyanate compound, a resin having two or more active hydrogen-containing groups capable of reacting with an isocyanate group in the blocked isocyanate compound, inorganic oxide fine particles, and an aqueous medium. It is a layer formed through thermosetting from a liquid,
The photosensitive layer is a single layer type photosensitive layer containing at least a charge generating material and a charge transport material, or a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material in this order or reverse order. There is provided a photoreceptor, which is a laminated photosensitive layer, wherein the charge generation material is oxotitanium phthalocyanine having a crystal structure.

  According to the present invention, the photosensitive member is formed by the exposure, the charging unit for charging the photosensitive member, the exposure unit for exposing the charged photosensitive member to form an electrostatic latent image, and the exposure. Developing means for developing the electrostatic latent image to form a toner image, transfer means for transferring the toner image formed by development onto a recording medium, and fixing the transferred toner image on the recording medium The image forming apparatus includes at least a fixing unit that forms an image, a cleaning unit that removes and collects toner remaining on the photoconductor, and a neutralizing unit that neutralizes surface charge remaining on the photoconductor. An apparatus is provided.

  According to the present invention, a photosensitive member having no volatile organic compound (VOC) and having the lowest environmental impact as a solvent and no danger of fire is used as a solvent. The intermediate layer formed using the intermediate layer coating solution and the photosensitive layer containing oxotitanium phthalocyanine having a crystal structure as a charge generating material solves the above problems, and has excellent repeatability and environmental stability. A photoreceptor and an image forming apparatus including the photoreceptor can be provided.

That is, according to the present invention, the use of an aqueous medium as a solvent for the intermediate layer coating solution not only eliminates the problem of air pollution due to VOC in the production process, but also uses conventional petroleum-based solvents. Since there is no problem of CO ₂ emission, it contributes to the prevention of global warming, and furthermore, there is no risk of fire, so the manufacturing system can be simplified and the manufacturing cost can be reduced.

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

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

  Furthermore, the present invention contains oxotitanium phthalocyanine having a crystal structure having high charge generation ability and high charge injection efficiency as the charge generation material of the photosensitive layer, and generates a large amount of charge by absorbing light. Since the generated charge can be efficiently injected into the charge transport material and intermediate layer without accumulating inside it, a highly sensitive photoconductor can be realized, and potential fluctuations due to environmental fluctuations and image defects such as memory images Can also be prevented. The reason is not clear, but the resin slightly shrinks when the intermediate layer is thermoset, and the added inorganic oxide fine particles are exposed on the surface of the intermediate layer. It is presumed that the number of contacts increases, and electrons in an excited state that cause a large amount of residence caused by oxotitanium phthalocyanine having a crystal structure effectively flow to the intermediate layer. That is, it is considered that the inorganic oxide fine particles control the electric resistance of the intermediate layer and prevent image defects such as repetitive characteristics and black spots.

FIG. 3 is a schematic cross-sectional view illustrating a configuration of a main part of the photoconductor of the present invention. FIG. 3 is a schematic cross-sectional view illustrating a configuration of a main part of the photoconductor of the present invention. FIG. 3 is a schematic cross-sectional view illustrating a configuration of a main part of the photoconductor of the present invention. It is a figure which shows the X-ray-diffraction spectrum of the crystalline oxotitanium phthalocyanine (crystal 1) of this invention. It is a figure which shows the X-ray-diffraction spectrum of the crystalline oxotitanium phthalocyanine (crystal 2) of this invention. It is a figure which shows the X-ray-diffraction spectrum of the crystalline oxotitanium phthalocyanine (crystal 3) of this invention. It is a figure which shows the X-ray-diffraction spectrum of the crystalline oxotitanium phthalocyanine (crystal 5) of this invention. It is a figure which shows the X-ray-diffraction spectrum of the crystalline oxotitanium phthalocyanine (crystal 6) of this invention. 1 is a schematic side view illustrating a configuration of an image forming apparatus of the present invention.

The photoreceptor of the present invention comprises an intermediate layer between the conductive support and the photosensitive layer,
Intermediate layer coating wherein the intermediate layer comprises a blocked isocyanate compound, a resin having two or more active hydrogen-containing groups capable of reacting with an isocyanate group in the blocked isocyanate compound, inorganic oxide fine particles, and an aqueous medium. It is a layer formed through thermosetting from a liquid,
The photosensitive layer is a single layer type photosensitive layer containing at least a charge generating material and a charge transport material, or a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material in this order or reverse order. It is a laminated photosensitive layer, and the charge generation material is oxotitanium phthalocyanine having a crystal structure.

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

In the photoreceptor of FIG. 1, an intermediate layer 2, a charge generation layer 3 containing a charge generation material, and a charge transport layer 4 containing a charge transport material are laminated in this order on the surface of a conductive support 1. The laminated photosensitive layer 5 is formed in this order.
In the photoreceptor of FIG. 2, an intermediate layer 2, a charge transport layer 4 containing a charge transport material, and a charge generation layer 3 containing a charge generation material are laminated in this order on the surface of the conductive support 1. The reverse two-layer type laminated photosensitive layer 5 is formed in this order.
In the photoreceptor of FIG. 3, an intermediate layer 2, a single-layer type photosensitive layer 5 ′ containing a charge generation material and a charge transport material are formed in this order on the surface of the conductive support 1.
The oxytitanium phthalocyanine having a crystal structure included in the intermediate layer, the charge generating layer of the multilayer photosensitive layer, or the single-layer photosensitive layer, which is a feature of the present invention, and other structures will be described in detail in this order.

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

In addition, the intermediate layer covering the surface of the conductive support reduces the degree of unevenness, which is a defect on the surface of the conductive support, makes the surface uniform, and forms a single layer type photosensitive layer or a multilayer type photosensitive layer. And the adhesion (adhesiveness) between the conductive support and the single-layer type photosensitive layer or the multilayer type photosensitive layer can be improved.
An intermediate | middle layer is obtained by apply | coating the coating liquid for intermediate | middle layers which has the above characteristics on an electroconductive support body, and hardening the obtained coating film, for example.

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

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

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

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

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

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

The active hydrogen-containing group in the resin having two or more active hydrogen-containing groups capable of reacting with the isocyanate group in the blocked isocyanate compound is preferably a hydroxyl group or an amide group capable of reacting with the isocyanate group in a high yield.
That is, it has two or more hydroxyl groups or amide groups to form a crosslinked structure with the blocked isocyanate as a curing agent (if it has only one functional group, it does not have a crosslinked structure but has a high molecular weight). Polyol resins and polyamide resins are preferred. In addition, by controlling the structure of these polyol resins and polyamide resins, it can be dispersed and dissolved in water satisfactorily. Furthermore, these resins have high adhesiveness to the substrate, so that they can be used together with the substrate as a photoreceptor. Image defects due to poor contact can also be effectively prevented.

As these polyol resin and polyamide resin, for example,
Product name: AQD-457 and AQD-473, Asahi Glass Co., Ltd., product name: Exenol 420 and 720, Sanyo Chemical Industries, Ltd., product name: Sannix GP-400, GP-700 And polyether polyol resins such as SP-750;
Hitachi Chemical Co., Ltd., product name: Phthalkid W2343, DIC Corporation, product name: Watersol S-118, CD-520 and BCD-3040, Harima Kasei Co., Ltd., product name: Hallidip WH-1188, etc. Polyester polyol resins of
DIC Corporation product name: Burnock WE-300, WE-304 and WE-306, Asia Industry Co., Ltd., product name: WAP-473-FD and WAP-548, Nuplex Industries Ltd., product name: SETAQUA6514 Such as polyacryl polyol 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;
Made by Nagase ChemteX Corporation, product name: Water-soluble nylon (polyamide compound resin) such as Toresin FS-350 and FS-500
Etc.

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

  The inorganic oxide fine particles contained in the coating solution for the intermediate layer adjust the volume resistance value of the intermediate layer when it is used as a photoreceptor, and prevent carrier injection from the conductive support to the photosensitive layer. It has the function of maintaining the electrical characteristics of the photoreceptor below.

  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 from the viewpoint of conductivity and dispersibility, 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 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), manufactured by Sakai Chemical Industry Co., Ltd.
Product name: MZ-300 (shape: granular, average primary particle size: 30-40 nm)
Examples thereof include fine particles of zinc oxide such as product name: F-2 (shape: rod shape, average primary particle size: 65 nm) manufactured by Hakusui Tech Co., Ltd.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

When the coating agent of the blocked isocyanate compound is removed, the resin having two or more active hydrogen-containing groups that can react with the isocyanate group in the blocked isocyanate compound starts an addition reaction with the isocyanate compound, and the coating is cured. Thermal curing is preferable.
The heat curing can be performed using a known apparatus such as a hot air drying furnace and a far-infrared drying furnace, and the conditions may be appropriately set depending on the type of block isocyanate compound or resin used, the mixing ratio, etc. The temperature is 110 to 150 ° C, preferably 130 to 150 ° C, and the time is about 10 minutes to 1 hour.

  Although the film thickness of an intermediate | middle layer is not specifically limited, 0.1-20 micrometers is preferable and 0.5-10 micrometers is especially preferable. If the film thickness of the intermediate layer is less than 0.1 μm, it does not substantially function as an intermediate layer, and a uniform surface property cannot be obtained by covering defects of the conductive support, and carriers are injected from the conductive support. May not be prevented, and the chargeability may decrease. 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 not only a single layer but also a plurality of layers.
For example, a first intermediate layer (conductive layer) having a thickness of 2 to 20 μm containing conductive inorganic oxide fine particles and a second intermediate layer (insulating layer) having a thickness of 0.2 to 1 μm not containing inorganic oxide fine particles. A first intermediate layer (insulating layer or blocking layer) having a thickness of 0.2 to 1 μm containing no inorganic oxide fine particles and a second film having a thickness of 3 to 10 μm containing electrically conductive inorganic oxide fine particles. Examples include a combination with an intermediate layer (moire prevention layer).

[Oxotitanium phthalocyanine with crystal structure]
As described later, oxotitanium phthalocyanine having a crystal structure can be obtained by pulverizing oxotitanium phthalocyanine in an organic solvent.
Oxotitanium phthalocyanine has the formula (A):

Wherein X ¹ , X ² , X ³ and X ⁴ are the same or different and are a halogen atom, an alkyl group or an alkoxy group, and r, s, y and z are the same or different and represent 0-4. It is an integer).

The halogen atom of X ^1, X ^2, X ³ and X ⁴ in formula (A), fluorine, chlorine, bromine and iodine atoms.
Examples of the alkyl group represented by X ¹ , X ² , X ³ and X ⁴ include alkyl groups having 1 to 4 carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group and t-butyl group. Is mentioned.
Examples of the alkoxy group for X ¹ , X ² , X ³ and X ⁴ include alkoxy having 1 to 4 carbon atoms such as methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group and t-butoxy group. Groups.

The oxotitanium phthalocyanine compound represented by the formula (A) is, for example, Phthhalocyanine Compounds, Reinhold Publishing Corp. by Moser, Frank H and Arthur L. Thomas.
, New York, 1963, and the like.

  For example, among the oxotitanium phthalocyanine compounds represented by the formula (A), in the case of an unsubstituted oxotitanium phthalocyanine in which r, s, y, and z are 0, are phthalonitrile and titanium tetrachloride heated and melted? Alternatively, it can be obtained by synthesizing dichlorotitanium phthalocyanine by heating in a suitable solvent such as α-chloronaphthalene and then hydrolyzing with base or water.

  Alternatively, oxotitanium phthalocyanine can be produced by reacting isoindoline with titanium tetraalkoxide such as tetrabutoxytitanium in a suitable solvent such as N-methylpyrrolidone.

  Specifically, as the oxotitanium phthalocyanine having a crystal structure, at least a Bragg angle (2θ ± 0.2 °) 27.1 to 27.3 ° in an X-ray diffraction spectrum using CuKα ray (1.541Å). Crystalline oxotitanium phthalocyanine exhibiting a diffraction peak at 2 and crystal oxotitanium phthalocyanine exhibiting a diffraction peak at 28.5 to 28.7 ° are preferred.

As such a crystalline oxotitanium phthalocyanine,
Generally known Y-type, M-type, I-type and α-type oxotitanium phthalocyanine,
As shown in FIG. 4, a maximum diffraction peak is shown at a Bragg angle 2θ (2θ ± 0.2 °) of 9.4 °, and a diffraction peak is shown at least at 7.3 °, 9.7 °, and 27.3 °, And crystalline oxotitanium phthalocyanine (Crystal 1), which has distinct branched peaks at 9.4 ° and 9.7 °, and shows a diffraction peak larger than the diffraction peak at 27.3 °,
As shown in FIG. 5, the Bragg angle 2θ (2θ ± 0.2 °) 9.5 °, 9.7 °, 11.7 °, 15.0 °, 23.5 °, 24.1 ° and 27. Crystalline oxotitanium phthalocyanine (crystal 2) with a major diffraction peak at 3 °,

Crystal oxotitanium phthalocyanine (crystal) having main diffraction peaks at Bragg angles 2θ (2θ ± 0.2 °) of 9.0 °, 14.2 °, 23.9 ° and 27.1 ° as shown in FIG. 3),
Crystalline oxotitanium phthalocyanine having a maximum diffraction peak at a Bragg angle 2θ (2θ ± 0.2 °) of 27.3 ° and having diffraction peaks at 7.4 °, 9.7 °, and 24.2 ° (crystal 4)
Bragg angle 2θ (2θ ± 0.2 °) 7.6 °, 12.6 °, 16.3 °, 22.5 °, 25.3 ° and 28.6 ° as shown in FIGS. Crystalline oxotitanium phthalocyanine showing major diffraction peaks (crystals 5 and 6)
These can be used, and these can be used alone or in combination of two or more.

As described above, oxotitanium phthalocyanine having such a crystal structure not only has high charge generation capability and high charge injection efficiency, but is also high in light in a long wavelength region such as near infrared light and red light. Indicates sensitivity. Therefore, a photoconductor using oxotitanium phthalocyanine having such a crystal structure as a charge generation material is suitable for a digital electrophotographic apparatus that uses light in a long wavelength region emitted from a semiconductor laser, a light emitting diode, or the like as an exposure source. Can be used.
In particular, the above crystalline oxotitanium phthalocyanine has a stable crystal form and is unlikely to be transferred to another crystal form. An excellent photoreceptor can be obtained.
From such a viewpoint, crystals 1 to 6 are preferable, crystals 1 to 3 and 5 are more preferable, and crystals 1 and 5 are particularly preferable.

  The oxotitanium phthalocyanine having a crystal structure is obtained by subjecting the oxotitanium phthalocyanine obtained by hydrolysis to a pulverization (milling) treatment with mechanical strain in an organic solvent such as methyl ethyl ketone, or stirring for a sufficient time. The former method is preferable.

Oxotitanium phthalocyanine having a crystal structure can also be obtained by treating oxotitanium phthalocyanine with a water-immiscible organic solvent such as dichloroethane in the presence of water.
Specifically, there are a method of treating oxotitanium phthalocyanine swollen with water with an organic solvent, a method of adding water to an organic solvent without performing the swelling treatment, and introducing oxotitanium phthalocyanine into the solvent, etc. Although it is mentioned, it is not limited to these.

  Examples of the method for swelling oxotitanium phthalocyanine with water include, for example, a method in which oxotitanium phthalocyanine is dissolved in sulfuric acid and precipitated in water to form a wet paste, and stirring / dispersing devices such as homomixers, paint mixers, ball mills, sand mills, etc. Is used to swell oxotitanium phthalocyanine with water to form a wet paste, but is not limited to these methods.

  The above crystals 1 to 4 are disclosed in JP 2000-129155 A (Patent Document 6), Japanese Patent No. 2700859 (Patent Document 4), JP 3-128973 A (Patent Document 5), and -91486 (patent document 6). The crystals 5 and 6 can be produced by the method described in JP-A-5-9402 (Patent Document 7).

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

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

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

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

[Charge generation layer 3]
The charge generation layer is mainly composed of oxotitanium phthalocyanine having the above-mentioned crystal structure, which is a charge generation material capable of generating charges by absorbing the irradiated light, and optionally known additives and binders. Contains resin (binder).

The charge generation layer may contain an appropriate amount of other charge generation materials as long as the preferable characteristics of the present invention are not impaired.
Such other charge generating materials include oxotitanium phthalocyanine and other phthalocyanine compounds having different crystal forms; bisazo compounds such as chlorodian blue, polycyclic quinone compounds such as dibromoanthanthrone, perylene compounds, quinacridone And azulenium salt compounds.

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

  The chemical sensitizer and the optical sensitizer improve the sensitivity of the photoreceptor, suppress an increase in residual potential and fatigue due to repeated use, and improve electrical durability.

  Examples of chemical sensitizers include acid anhydrides such as succinic anhydride, maleic anhydride, phthalic anhydride, and 4-chloronaphthalic anhydride; cyano compounds such as tetracyanoethylene and terephthalmalondinitrile, and 4-nitrobenzaldehyde. Aldehydes; anthraquinones such as anthraquinone and 1-nitroanthraquinone; polycyclic or heterocyclic nitro compounds such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitrofluorenone; diphenoquinone compounds Examples thereof include electron-withdrawing materials and those obtained by polymerizing these electron-withdrawing materials.

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

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

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

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

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

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

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

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

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

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

The application method of the coating solution for the charge generation layer is a baker applicator method, a bar coater method, a casting method, a spin coating method, a roll method, a blade method or the like in the case of a sheet, and a spray method or a vertical ring method in the case of a drum. And a dip coating method.
As an application method, an optimum method may be selected in consideration of physical properties and productivity of the coating liquid, and an immersion method, a blade coater method, and a spray method are particularly preferable.

Although it will not specifically limit if the temperature in the drying process of a coating film is the temperature which can remove the used organic solvent, 50-140 degreeC is suitable and 80-130 degreeC is especially preferable.
When the drying temperature is less than 50 ° C., the drying time may be long. On the other hand, if the drying temperature exceeds 140 ° C., the electrical characteristics during repeated use of the photoreceptor may deteriorate and the resulting image may deteriorate.

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

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

As the charge transport material, a compound used in this field can be used.
Specifically, carbazole derivatives, imidazole derivatives, oxazole derivatives, thiadiazole derivatives, polycyclic aromatic compounds, aniline compounds, hydrazone compounds, aromatic amine compounds, triphenylamine compounds and their dimers, triphenyl Hole transport materials such as methane-based compounds, tetraphenylbutadiene-based compounds, enamine-based compounds and stilbene-based compounds, and polymers such as poly-N-vinylcarbazole having groups derived from these compounds in the main chain or side chain;

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

The ratio (E / B) between the weight (E) of the charge transport material and the weight (B) of the binder resin is 10/12 to 10/25, preferably 10/16 to 10/20.
When the ratio (E / B) is less than 10/25, the relative amount ratio of the binder resin to the charge transport material is increased, and sufficient sensitivity may not be obtained.
On the other hand, if the ratio (E / B) exceeds 10/12, the printing durability of the charge transport layer and the durability of the photoreceptor may be lowered.

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

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

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

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

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

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

  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.

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

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

  Although the film thickness of a protective layer is not specifically limited, 0.5-10 micrometers is preferable and 1-5 micrometers is especially preferable. 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 may be reduced. There is.

  The image forming apparatus of the present invention is formed by exposure, the photosensitive member of the present invention, a charging unit for charging the photosensitive member, an exposure unit for exposing the charged photosensitive member to form an electrostatic latent image, and exposure. Developing means for developing the electrostatic latent image to form a toner image; transfer means for transferring the toner image formed by development onto a recording medium; and transferring the transferred toner image onto the recording medium. The image forming apparatus includes at least a fixing unit that fixes and forms an image, 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.

The image forming apparatus of the present invention will be described with reference to the drawings, but is not limited to the following description.
FIG. 9 is a schematic side view showing the configuration of the image forming apparatus of the present invention.
The image forming apparatus 20 in FIG. 9 includes a photoconductor 21 of the present invention (for example, any one of the photoconductors in FIGS. 1 to 3), a charging unit (charger) 24, an exposure unit 28, and a developing unit ( Development unit) 25, transfer unit (transfer unit) 26, cleaning unit (cleaner) 27, fixing unit (fixing unit) 31, and charge eliminating unit (not shown, attached to cleaning unit 27). Composed. Reference numeral 30 indicates a recording medium (transfer paper).

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Example 1
As the conductive support, a cylindrical conductive support made of aluminum having a diameter of 30 mm, a length of 300 mm, and a thickness of 0.8 mm was used to produce the photoconductor of FIG.
First, titanium oxide fine particles surface-treated with aluminum oxide (Al ₂ O ₃ ) and zirconium dioxide (ZrO ₂ ) as inorganic oxide fine particles (shape: dendritic, average primary particle size: minor axis 40-70 nm, long Axis 200-300 nm, manufactured by Ishihara Sangyo Co., Ltd., product name: TTO-D-1) 16 parts by weight, and water-based polyol polyvinyl acetal resin as resin (solid content: 20%, OH value: 570, Sekisui Chemical Co., Ltd.) Manufactured by Co., Ltd., product name: ESREC K KW-3) 1.6 parts by weight, blocked isocyanate compound (solid content: 37.5%, NCO content: 3.7%, manufactured by Sumika Bayer Urethane Co., Ltd., product Name: Bihijole VPLS2310) 9.8 parts by weight and antifoaming agent (oil compound type, manufactured by San Nopco, product name: SN deformer 777) 08 parts by weight and a dispersion stabilizer (manufactured by San Nopco, product name: Roma PWA-40): 0.04 parts by weight are added to 73 parts by weight of water and dispersed for 6 hours using a paint shaker to form an intermediate layer A coating solution (total amount 1 kg) was prepared.
The isocyanate group of the blocked isocyanate compound is in a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) are based on the cross-linked resin (total of the blocked isocyanate compound and the resin: R). The weight ratio (P / R) was 8/2.
The obtained coating solution for the intermediate layer is filled in the 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 an intermediate film thickness of 1.0 μm. A layer was formed.

  Next, 2 parts by weight of crystalline oxotitanium phthalocyanine showing the diffraction peak of FIG. 4 as a charge generation material, and 1 part by weight of polyvinyl butyral resin (product name: ESREC B BM-S, manufactured by Sekisui Chemical Co., Ltd.) as a binder resin. And 97 parts by weight of methyl ethyl ketone as an organic solvent were mixed and dispersed for 1 hour using a paint shaker to prepare a charge generation layer coating solution (total amount: 1 kg). This charge generation layer coating solution was applied onto the previously formed intermediate layer by the same dip coating method as that for the intermediate layer, and then naturally dried to form a charge generation layer having a thickness of 0.2 μm.

Next, 10 parts by weight of a triphenylamine-butadiene derivative represented by the following structural formula (1) as a charge transporting substance and 18 parts by weight of a polycarbonate resin (product name: Iupilon Z400, manufactured by Mitsubishi Engineering Plastics Co., Ltd.) as a binder resin Parts, 0.5 parts by weight of 2,6-di-t-butyl-4-methylphenol as an antioxidant, and dimethylpolysiloxane as a leveling agent (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KF-96) ) 0.004 part by weight was dissolved in 110 parts by weight of tetrahydrofuran (THF) as an organic solvent to prepare a charge transport layer coating solution (total amount: 1 kg). This charge transport layer coating solution is applied onto the previously formed charge generation layer by the same dip coating method as that for the intermediate layer, and dried at a temperature of 130 ° C. for 1 hour to form a charge transport layer having a thickness of 23 μm. did.
The photoreceptor of Example 1 was produced as described above.

(Example 2)
The photosensitivity of Example 2 was the same as that of Example 1, except that the crystalline oxotitanium phthalocyanine having the diffraction peak shown in FIG. The body was made.
The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution has a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) The weight ratio (P / R) was 8/2 with respect to the total: R).

(Example 3)
The photosensitivity of Example 3 was the same as that of Example 1, except that the crystalline oxotitanium phthalocyanine having the diffraction peak of FIG. The body was made.
The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution has a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) The weight ratio (P / R) was 8/2 with respect to the total: R).

Example 4
Example 4 was carried out in the same manner as in Example 1 except that Y-type oxotitanium phthalocyanine (manufactured by Orient Chemical Industry Co., Ltd.) was used in place of the crystalline oxotitanium phthalocyanine showing the diffraction peak of FIG. A photoconductor was prepared.
The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution has a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) The weight ratio (P / R) was 8/2 with respect to the total: R).

(Example 5)
Example 5 was carried out in the same manner as in Example 1 except that type I oxotitanium phthalocyanine (manufactured by Orient Chemical Co., Ltd.) was used in place of the crystalline oxotitanium phthalocyanine showing the diffraction peak of FIG. A photoconductor was prepared.
The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution has a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) The weight ratio (P / R) was 8/2 with respect to the total: R).

(Example 6)
A photoconductor of Example 6 was produced in the same manner as in Example 1 except that the intermediate layer coating solution was prepared with the following components.
Titanium oxide fine particles as inorganic oxide fine particles (shape: dendritic, 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): 16 weight Part Water-soluble cellulose ether as a resin (OH value: 360, manufactured by Shin-Etsu Chemical Co., Ltd., product name: Metroles 65SH-400): 0.5 part by weight Block isocyanate compound (solid content: 37.5%, NCO content) : 3.7%, manufactured by Sumika Bayer Urethane Co., Ltd., product name: Bihijoule VPLS2310): 9.4 parts by weight Defoaming agent (oil compound type, manufactured by San Nopco, product name: SN deformer 777): 0.08 Part by weight Dispersion stabilizer Dispersion stabilizer (manufactured by San Nopco, product name: Roma PWA-40): 0.04 part by weight Water: 74 part by weight The isocyanate group of the blocked isocyanate compound in the layer coating liquid has a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) are cross-linked resins (the sum of the blocked isocyanate compound and the resin). : R) and the weight ratio (P / R) was 8/2.

(Example 7)
As inorganic oxide fine particles, instead of titanium oxide fine particles, zinc oxide fine particles (average primary particle size: 35 nm, manufactured by Sakai Chemical Industry Co., Ltd., product name: FINEX30) were used in the same manner as in Example 1. A photoconductor of Example 7 was produced.
The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution has a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) The weight ratio (P / R) was 8/2 with respect to the total: R).

(Example 8)
As inorganic oxide fine particles, instead of titanium oxide fine particles, zinc oxide fine particles (average primary particle size: 30 to 40 nm, manufactured by Teika Co., Ltd., product name: MZ300) were used in the same manner as in Example 6. A photoconductor of Example 8 was produced.
The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution has a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) The weight ratio (P / R) was 8/2 with respect to the total: R).

Example 9
A photoconductor of Example 9 was produced in the same manner as in Example 1 except that the intermediate layer coating solution was prepared with the following components.
Titanium oxide fine particles as inorganic oxide fine particles (shape: dendritic, 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): 16 weight Part Polyether polyol resin (water dispersion type, solid content: 35%, OH value: 60, manufactured by Nippon Polyurethane Industry Co., Ltd., product name: AQD-473): 5.2 parts by weight Block isocyanate compound (solid Minute: 37.5%, NCO content: 3.7%, manufactured by Sumika Bayer Urethane Co., Ltd., product name: Bihijoule VPLS2310): 5.8 parts by weight Defoaming agent (oil compound system, manufactured by San Nopco Co., Ltd., product) Name: SN deformer 777): 0.08 parts by weight Dispersion stabilizer Dispersion stabilizer (manufactured by San Nopco, product name: Roma PWA-40): 0.04 Part by weight Water: 70 parts by weight The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution has a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) are crosslinked resins. The weight ratio (P / R) was 8/2 with respect to (total of blocked isocyanate compound and resin: R).

(Example 10)
A photoconductor of Example 10 was produced in the same manner as in Example 1 except that the intermediate layer coating solution was prepared with the following components.
Zinc oxide fine particles as inorganic oxide fine particles (average primary particle size: 30 to 40 nm, manufactured by Teika Co., Ltd., product name: MZ300): 16 parts by weight Aqueous polyol polyvinyl acetal resin (solid content: 20%, resin) OH value: 960, manufactured by Sekisui Chemical Co., Ltd., product name: ESREC K KW-1): 1.4 parts by weight Block isocyanate compound (solid content: 45%, water dispersion type, NCO content: 7%, Mitsui Chemicals) Made by Polyurethane Co., Ltd., product name: Takenate WB-820): 9.3 parts by weight Defoaming agent (oil compound, manufactured by San Nopco, product name: SN deformer 777): 0.08 parts by weight Dispersion stabilizer dispersion stability Agent (manufactured by San Nopco, product name: Roma PWA-40): 0.04 parts by weight Water: 73 parts by weight Block in coating solution for intermediate layer The isocyanate group of the isocyanate compound is in a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) are 8 to the cross-linked resin (total of the blocked isocyanate compound and the resin: R). The weight ratio (P / R) was / 2.

(Comparative Example 1)
A photoreceptor of Comparative Example 1 was produced in the same manner as in Example 1 except that the intermediate layer coating solution (organic solvent type, no curing agent) was prepared with the following components.
Titanium oxide fine particles as inorganic oxide fine particles (shape: dendritic, 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): 8 weight Part Copolymer nylon as a resin (product name: Amilan CM8000, manufactured by Toray Industries, Inc.): 2 parts by weight Methanol: 50 parts by weight 1,3-dioxolane: 40 parts by weight

(Comparative Example 2)
Comparative Example 2 is the same as Comparative Example 1 except that the crystalline oxotitanium phthalocyanine having the diffraction peak of FIG. 5 is used as the charge generation material instead of the crystalline oxotitanium phthalocyanine having the diffraction peak of FIG. A photoreceptor was prepared.

(Comparative Example 3)
A photoconductor of Comparative Example 3 was produced in the same manner as in Example 1 except that the intermediate layer coating solution (aqueous, no curing agent) was prepared with the following components.
Titanium oxide fine particles as inorganic oxide fine particles (shape: dendritic, 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): 8 weight Part Polyvinyl acetal resin of water-based polyol as resin (solid content: 20%, OH value: 570, manufactured by Sekisui Chemical Co., Ltd., product name: ESREC K KW-3): 10 parts by weight Water: 82 parts by weight

(Comparative Example 4)
A photoconductor of Comparative Example 4 was prepared in the same manner as in Example 1 except that X-type metal oxotitanium phthalocyanine was used as the charge generation material instead of the crystalline oxotitanium phthalocyanine showing the diffraction peak of FIG. .

(Comparative Example 5)
Comparative Example 5 was the same as Example 1 except that a trisazo pigment represented by the following structural formula (2) was used as the charge generation material instead of the crystalline oxotitanium phthalocyanine having the diffraction peak of FIG. A photoreceptor was prepared.

(Evaluation)
(1) Electrical Characteristics and Environmental Stability of Photoreceptor The photoreceptor obtained in Examples 1 to 10 and Comparative Examples 1 to 5 was measured with a surface potential meter (Gen) so that the surface potential of the photoreceptor in the image forming process could be measured. Each of the photoconductors was evaluated for electrical characteristics and environmental stability by being mounted on a commercially available digital copying machine (Sharp Corporation, model: AR-F330) provided with a TEC Co., Ltd. model: CATE751).
First, in an 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 was measured as a charging potential V0 (V). Further, the surface potential of the photoreceptor immediately after being exposed by laser light (wavelength: 780 nm) was measured as a residual potential VL (V) in an N / N environment.
Further, the residual potential VL (V) is measured in an N / H environment at a temperature of 25 ° C. and a relative humidity of 85% and in an N / L environment at a temperature of 25 ° C. and a relative humidity of 5% in the same manner as in the N / N environment. These differences were obtained as potential fluctuation ΔVL (V). That is, it can be evaluated that the smaller the potential fluctuation ΔVL (V), the better the environmental stability (environmental characteristics).
The obtained results are shown in Table 1. In Table 1, the solvents used for the intermediate layer coating solution are additionally shown.

Further, a blank paper image was output under an H / H environment at a temperature of 30 ° C. and a relative humidity of 80%, and black spots were evaluated based on the following criteria.
Further, in a N / L environment at a temperature of 25 ° C. and a relative humidity of 5%, a basic pattern for one round of the drum was printed, and then an entire halftone image was printed. The memory image was evaluated based on the following criteria. .
○: None △: Slightly observed (practical)
×: Observed clearly (not practical)
The obtained results are shown in Table 1.

Next, in a N / N environment at a temperature of 22 ° C. and a relative humidity of 65%, a test image having a predetermined pattern (a character test chart defined in ISO 19752) was continuously copied on 100,000 sheets of recording paper, In the same manner as in the initial stage, the surface potential of the photoconductor immediately after the charging operation is measured as a charging potential V0 (V), and the surface potential of the photoconductor after exposure is measured as a residual potential VL (V). It was determined as a potential fluctuation ΔVLS (V) which is an index of fatigue characteristics.
The obtained results are shown in Table 1.

(2) Pot life After the intermediate layer coating solutions prepared in Examples 1 to 10 and Comparative Examples 1 to 5 were stored for 6 months under normal temperature and normal humidity (temperature 20 ° C., humidity 50%), the same manner was performed. A photoconductor was prepared, and the obtained photoconductor was measured for a residual potential VL (V) under an N / N environment, and the difference from the value of the initial residual potential VL (V) in the above (1) was It was obtained as a potential fluctuation ΔVLP (V) which is an index of life.
The obtained results are shown in Table 1.

The following can be seen from the results in Table 1.
(1) The photoconductor of the present invention (Examples 1 to 10) is a polyamide-based binder that is widely used in current photoconductors even though water is used as a solvent for the intermediate layer coating solution. Compared with the organic solvent-based photoconductors of Comparative Examples 1 and 2 using resin, all of the electrical characteristics, environmental stability, fatigue characteristics, and coating liquid stability (pot life) have equal or better performance. Yes.
(2) On the photoconductor (Comparative Examples 1 and 2) having an intermediate layer formed using an intermediate layer coating solution (organic solvent type, no curing agent), a memory image is observed. In the body (Examples 1 to 10), no memory image is observed.
(3) In a photoreceptor (Comparative Example 3) having an intermediate layer formed using an intermediate layer coating solution (aqueous, no curing agent), environmental characteristics are extremely deteriorated.
(4) Photoconductors (Comparative Examples 4 and 5) having a charge generation layer formed using an X-type metal oxotitanium phthalocyanine and a trisazo pigment as charge generation materials are obtained from the photoconductors of the present invention (Examples 1 to 10). The sensitivity was low and VL was high.

(Example 11)
As the conductive support, a cylindrical conductive support made of aluminum having a diameter of 30 mm, a length of 357 mm, and a thickness of 0.8 mm was used to produce the photoconductor of FIG.
First, titanium oxide fine particles (shape: granular, average primary particle size: 35 nm, manufactured by Teika Co., Ltd., product name: MT-500SAS) as inorganic oxide fine particles, and an aqueous polyol polyvinyl acetal resin as a resin (Solid content: 20%, OH value: 570, manufactured by Sekisui Chemical Co., Ltd., product name: ESREC K KW-3) 3.1 parts by weight and a blocked isocyanate compound (solid content: 70%, NCO content: 7 .9%, Asahi Kasei Chemicals Corporation, developed product name: X1248) 4.8 parts by weight, antifoaming agent (oil compound, San Nopco, product name: SN deformer 777) 0.02 parts by weight, dispersed Stabilizer (manufactured by Sannopco, product name: Roma PWA-40): 0.04 parts by weight is added to 73 parts by weight of water, and a paint shaker is used. Intermediate layer coating solution (total volume 1 kg) was prepared by time dispersion process.
The isocyanate group of the blocked isocyanate compound is in a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) are based on the cross-linked resin (total of the blocked isocyanate compound and the resin: R). The weight ratio (P / R) was 8/2.
The obtained coating solution for the intermediate layer is filled in the 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 an intermediate film thickness of 1.0 μm. A layer was formed.

  Next, 2 parts by weight of crystalline oxotitanium phthalocyanine (crystal 1) showing the diffraction peak of FIG. 4 as a charge generating substance, and polyvinyl butyral resin (product name: ESREC B BM-S, manufactured by Sekisui Chemical Co., Ltd.) as a binder resin. ) 1 part by weight and 97 parts by weight of methyl ethyl ketone as an organic solvent were mixed and dispersed for 1 hour using a paint shaker to prepare a charge generation layer coating solution (total amount: 1 kg). This charge generation layer coating solution was applied onto the previously formed intermediate layer by the same dip coating method as that for the intermediate layer, and then naturally dried to form a charge generation layer having a thickness of 0.2 μm.

Next, 10 parts by weight of a triphenylamine-butadiene derivative represented by the above structural formula (1) as a charge transport material and 18 parts by weight of a polycarbonate resin (product name: Iupilon Z400, manufactured by Mitsubishi Engineering Plastics Co., Ltd.) as a binder resin. Parts, 0.5 parts by weight of 2,6-di-t-butyl-4-methylphenol as an antioxidant, and dimethylpolysiloxane as a leveling agent (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KF-96) ) 0.004 part by weight was dissolved in 110 parts by weight of tetrahydrofuran (THF) as an organic solvent to prepare a charge transport layer coating solution (total amount: 1 kg). This charge transport layer coating solution is applied onto the previously formed charge generation layer by the same dip coating method as that for the intermediate layer, and dried at a temperature of 130 ° C. for 1 hour to form a charge transport layer having a thickness of 23 μm. did.
As described above, a photoconductor of Example 11 was produced.

Example 12
The same procedure as in Example 11 was carried out except that the crystalline oxotitanium phthalocyanine (crystal 2) showing the diffraction peak of FIG. 5 was used as the charge generating substance instead of the crystalline oxotitanium phthalocyanine showing the diffraction peak of FIG. The photoreceptor of Example 12 was produced.
The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution has a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) The weight ratio (P / R) was 8/2 with respect to the total: R).

(Example 13)
The same procedure as in Example 11 was carried out except that the crystalline oxotitanium phthalocyanine (crystal 3) showing the diffraction peak of FIG. 6 was used as the charge generating substance instead of the crystalline oxotitanium phthalocyanine showing the diffraction peak of FIG. The photoreceptor of Example 13 was produced.
The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution has a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) The weight ratio (P / R) was 8/2 with respect to the total: R).

(Example 14)
Example 14 was carried out in the same manner as in Example 11 except that Y-type oxotitanium phthalocyanine (manufactured by Orient Chemical Industry Co., Ltd.) was used as the charge generation material instead of the crystalline oxotitanium phthalocyanine showing the diffraction peak of FIG. A photoconductor was prepared.
The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution has a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) The weight ratio (P / R) was 8/2 with respect to the total: R).

(Example 15)
Example 15 was carried out in the same manner as in Example 11 except that type I oxotitanium phthalocyanine (manufactured by Orient Chemical Co., Ltd.) was used in place of the crystalline oxotitanium phthalocyanine showing the diffraction peak of FIG. A photoconductor was prepared.
The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution has a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) The weight ratio (P / R) was 8/2 with respect to the total: R).

(Example 16)
Implementation was performed except that α-type oxotitanium phthalocyanine (Nippon Materials Co., Ltd., Crystal 5) showing the diffraction peak of FIG. 7 was used as the charge generation material instead of the crystalline oxotitanium phthalocyanine showing the diffraction peak of FIG. In the same manner as in Example 11, a photoconductor of Example 16 was produced.
The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution has a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) The weight ratio (P / R) was 8/2 with respect to the total: R).

(Example 17)
As the charge generation material, α-type oxotitanium phthalocyanine having a diffraction peak of FIG. 8 (manufactured by Permachem Asia Co., Ltd., crystal 6) was used in place of the crystalline oxotitanium phthalocyanine having the diffraction peak of FIG. In the same manner as in Example 11, a photoconductor of Example 17 was produced.
The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution has a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) The weight ratio (P / R) was 8/2 with respect to the total: R).

(Example 18)
A photoconductor of Example 18 was produced in the same manner as Example 11 except that the intermediate layer coating solution was prepared using the following components.
Titanium oxide fine particles as inorganic oxide fine particles (shape: dendritic, 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 weight Part Water-soluble cellulose ether as a resin (OH value: 360, manufactured by Shin-Etsu Chemical Co., Ltd., product name: Metroles 65SH-400): 0.96 parts by weight Block isocyanate compound (solid content: 37.5%, NCO content) : 3.7%, manufactured by Sumika Bayer Urethane Co., Ltd., product name: Bihijoule VPLS2310): 18.8 parts by weight Antifoaming agent (oil compound system, manufactured by San Nopco, product name: SN deformer 777): 0.02 Part by weight Dispersion stabilizer Dispersion stabilizer (manufactured by San Nopco, product name: Roma PWA-40): 0.03 part by weight Water: 68% by weight The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution has a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) are crosslinked resins (block isocyanate compound and resin of the resin). The weight ratio (P / R) was 6/4 with respect to the total: R).

(Example 19)
A photoconductor of Example 19 was produced in the same manner as Example 11 except that the intermediate layer coating solution was prepared using the following components.
Zinc oxide fine particles as inorganic oxide fine particles (shape: granular, average primary particle size: 35 nm, manufactured by Sakai Chemical Industry Co., Ltd., product name: FINEX30): 12 parts by weight Polyether polyol as resin (solid content: 35%, OH value: 60, manufactured by Nippon Polyurethane Industry Co., Ltd., product name: AQD-473): 14.3 parts by weight Block isocyanate compound (solid content: 42%, NCO content: 7.5%, manufactured by Nippon Polyurethane Industry Co., Ltd.) Development name: BWD-102): 7.1 parts by weight Antifoaming agent (oil compound, manufactured by San Nopco, product name: SN deformer 777): 0.02 parts by weight Dispersion stabilizer Dispersion stabilizer (San Nopco) Manufactured, product name: Roma PWA-40): 0.03 parts by weight Water: 69 parts by weight Block isocyanate in the intermediate layer coating solution The isocyanate group of the product has a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) have a ratio of 6 / to the cross-linked resin (total of blocked isocyanate compound and resin: R). The weight ratio (P / R) was 4.

(Example 20)
A photoconductor of Example 20 was produced in the same manner as Example 11 except that the intermediate layer coating solution was prepared using the following components.
Zinc oxide fine particles as inorganic oxide fine particles (shape: granular, average primary particle size: 35 nm, manufactured by Sakai Chemical Industry Co., Ltd., product name: FINEX30): 10 parts by weight Polyvinyl acetal as resin (solid content: 20%, OH Value: 570, manufactured by Sekisui Chemical Co., Ltd., product name: KW-3): 5.6 parts by weight Block isocyanate compound (solid content: 40%, NCO content: 5.4%, manufactured by Mitsui Chemicals Polyurethane Co., Ltd.) Product name: Takenate WB-920)
: 22.2 parts by weight Antifoaming agent (oil compound, manufactured by San Nopco, product name: SN deformer 777): 0.02 parts by weight Dispersion stabilizer dispersion stabilizer (manufactured by San Nopco, product name: Roma PWA-) 40): 0.03 part by weight Water: 62 part by weight The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution has a molar ratio of 1.0 to the active hydrogen-containing group of the resin. P) was a weight ratio (P / R) of 5/5 with respect to the cross-linked resin (total of blocked isocyanate compound and resin: R).

(Example 21)
A photoconductor of Example 21 was produced in the same manner as Example 11 except that the intermediate layer coating solution was prepared using the following components.
Titanium oxide fine particles as inorganic oxide fine particles (shape: granular, average primary particle size: 20 nm, manufactured by Ishihara Sangyo Co., Ltd., product name: ST-21): 14 parts by weight Polyether polyol resin (water dispersion type) as resin Solid content: 35%, OH value: 60, manufactured by Nippon Polyurethane Industry Co., Ltd., product name: AQD-473): 7.7 parts by weight Block isocyanate compound (solid content: 37.5%, NCO content: 3. 7%, manufactured by Sumika Bayer Urethane Co., Ltd., product name: Bihijoule VPLS2310): 8.8 parts by weight Antifoaming agent (oil compound type, manufactured by San Nopco, product name: SN deformer 777): 0.02 parts by weight Dispersion Stabilizer dispersion stabilizer (manufactured by Sannopco, product name: Roma PWA-40): 0.04 parts by weight Water: 70 parts by weight In the intermediate layer coating solution The isocyanate group of the blocked isocyanate compound is 1.0 molar ratio to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) are based on the cross-linked resin (total of the blocked isocyanate compound and the resin: R). The weight ratio (P / R) was 7/3.

(Example 22)
A photoconductor of Example 22 was produced in the same manner as Example 11 except that the intermediate layer coating solution was prepared using the following components.
Zinc oxide fine particles as inorganic oxide fine particles (shape: rod shape, average primary particle size: 65 nm, manufactured by Hakusuitec Co., Ltd., product name: F-2): 12 parts by weight Polyacryl polyol as resin (solid content: 45%, OH value: 80, manufactured by DIC Corporation, product name: Burnock WE-300): 9.6 parts by weight Block isocyanate compound (solid content: 45%, water dispersion type, NCO content: 7.0%, Mitsui Chemicals Polyurethane) Product name: Takenate WB-820): 8.2 parts by weight Defoaming agent (oil compound, manufactured by San Nopco, product name: SN deformer 777): 0.02 parts by weight Dispersion stabilizer Dispersion stabilizer (Manufactured by San Nopco, product name: Rome PWA-40): 0.03 parts by weight Water: 70 parts by weight Block isocyanate in the intermediate layer coating solution The isocyanate group of the compound is in a molar ratio of 1.0 to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) are 6 / The weight ratio (P / R) was 4.

(Example 23)
A photoconductor of Example 23 was produced in the same manner as Example 11 except that the intermediate layer coating solution was prepared using the following components.
Titanium oxide fine particles as inorganic oxide fine particles (average primary particle size: 35 nm, manufactured by Teika Co., Ltd., product name: MT-500SAS): 16 parts by weight Water-soluble nylon as resin (solid content: 20%, NH content) : 10%, manufactured by Nagase ChemteX Corporation, product name: Toresin FS-350): 4.8 parts by weight Block isocyanate compound (solid content: 70%, NCO content: 7.9%, manufactured by Asahi Kasei Chemicals Corporation, Development name: X1248): 4.3 parts by weight Antifoaming agent (oil compound, manufactured by San Nopco, product name: SN deformer 777): 0.02 parts by weight Dispersion stabilizer dispersion stabilizer (produced by San Nopco, product) Name: Roma PWA-40): 0.04 parts by weight Water: 75 parts by weight Isocyanate of blocked isocyanate compound in intermediate layer coating solution Group is 1.0 molar ratio relative to the active hydrogen-containing group of the resin, and the inorganic oxide fine particles (P) are 8/2 relative to the cross-linked resin (total of blocked isocyanate compound and resin: R). The weight ratio (P / R).

(Example 24)
As the charge generation material, α-type oxotitanium phthalocyanine (Nippon Materials Co., Ltd., Crystal 5) showing the diffraction peak of FIG. 7 is used instead of the crystalline oxotitanium phthalocyanine showing the diffraction peak of FIG. A photoconductor of Example 24 was made in the same manner as Example 11 except that the liquid was prepared using the following components.
Tin oxide as inorganic oxide fine particles (shape: spherical, average primary particle size: 30 nm, manufactured by Mitsubishi Materials Corporation, product name: S-2000): 8 parts by weight Polyvinyl acetal as resin (solid content: 20%, OH Value: 570, manufactured by Sekisui Chemical Co., Ltd., product name: KW-3): 9.4 parts by weight Block isocyanate compound (solid content: 70%, NCO content: 7.9%, manufactured by Asahi Kasei Chemicals Corporation, developed) Product name: X1248): 14.5 parts by weight Antifoaming agent (oil compound, manufactured by San Nopco, product name: SN deformer 777): 0.02 parts by weight Dispersion stabilizer dispersion stabilizer (produced by San Nopco, product name) : Roma PWA-40): 0.02 parts by weight Water: 68 parts by weight The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution is In the molar ratio of 1.0 to the active hydrogen-containing group of the inorganic oxide fine particles (P), the weight ratio (P / R).

(Example 25)
A photoconductor of Example 25 was produced in the same manner as Example 11 except that the coating solution for intermediate layer was prepared with the following components.
Titanium oxide fine particles as inorganic oxide fine particles (average primary particle size: 35 nm, manufactured by Teika Co., Ltd., product name: MT-500SAS): 16 parts by weight Polyvinyl acetal as a resin (solid content: 20%, OH value: 960) , Manufactured by Sekisui Chemical Co., Ltd., product name: KW-1): 4.3 parts by weight Block isocyanate compound (solid content: 70%, NCO content: 7.9%, manufactured by Asahi Kasei Chemicals Corporation, developed product name: X1248 ): 4.5 parts by weight Antifoaming agent (oil compound system, manufactured by San Nopco, product name: SN deformer 777): 0.02 parts by weight Dispersion stabilizer dispersion stabilizer (manufactured by San Nopco, product name: Roma PWA) -40): 0.04 parts by weight Water: 75 parts by weight The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution is the active part of the resin. The inorganic oxide fine particles (P) have a weight ratio (P / R) of 8/2 with respect to the cross-linked resin (total of blocked isocyanate compound and resin: R) at a molar ratio of 0.4 to the functional hydrogen-containing group. )Met.

(Example 26)
A photoreceptor of Example 26 was made in the same manner as Example 11 except that the intermediate layer coating solution was prepared using the following components.
Titanium oxide fine particles as inorganic oxide fine particles (average primary particle size: 35 nm, manufactured by Teika Co., Ltd., product name: MT-500SAS): 16 parts by weight Polyvinyl acetal as a resin (solid content: 20%, OH value: 960) Manufactured by Sekisui Chemical Co., Ltd., product name: KW-1): 3.1 parts by weight Block isocyanate compound (solid content: 70%, NCO content: 7.9%, manufactured by Asahi Kasei Chemicals Corporation, developed product name: X1248 ): 4.8 parts by weight Antifoaming agent (oil compound, San Nopco, product name: SN deformer 777): 0.02 parts by weight Dispersion stabilizer dispersion stabilizer (San Nopco, product name: Roma PWA) -40): 0.04 parts by weight Water: 76 parts by weight The isocyanate group of the blocked isocyanate compound in the intermediate layer coating liquid is the resin activity. The inorganic oxide fine particles (P) have a weight ratio of 8/2 to the cross-linked resin (total of blocked isocyanate compound and resin: R) at a molar ratio of 0.6 to the functional hydrogen-containing group (P / R). )Met.

(Example 27)
A photoconductor of Example 27 was produced in the same manner as Example 11 except that the intermediate layer coating solution was prepared using the following components.
Titanium oxide fine particles as inorganic oxide fine particles (average primary particle size: 35 nm, manufactured by Teika Co., Ltd., product name: MT-500SAS): 16 parts by weight Polyvinyl acetal as a resin (solid content: 20%, OH value: 960) Manufactured by Sekisui Chemical Co., Ltd., product name: KW-1): 1.5 parts by weight Block isocyanate compound (solid content: 70%, NCO content: 7.9%, manufactured by Asahi Kasei Chemicals Corporation, developed product name: X1248 ): 5.3 parts by weight Antifoaming agent (oil compound type, manufactured by San Nopco, product name: SN deformer 777): 0.02 parts by weight Dispersion stabilizer dispersion stabilizer (manufactured by San Nopco, product name: Roma PWA) -40): 0.04 parts by weight Water: 77 parts by weight The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution is the resin activity. The inorganic oxide fine particles (P) have a weight ratio (P / R) of 8/2 to the cross-linked resin (total of the blocked isocyanate compound and the resin: R) at a molar ratio of 1.4 to the functional hydrogen-containing group. )Met.

(Example 28)
A photoconductor of Example 28 was produced in the same manner as Example 11 except that the intermediate layer coating solution was prepared using the following components.
Titanium oxide fine particles as inorganic oxide fine particles (average primary particle size: 35 nm, manufactured by Teika Co., Ltd., product name: MT-500SAS): 16 parts by weight Polyvinyl acetal as a resin (solid content: 20%, OH value: 960) , Manufactured by Sekisui Chemical Co., Ltd., product name: KW-1): 1.3 parts by weight Block isocyanate compound (solid content: 70%, NCO content: 7.9%, manufactured by Asahi Kasei Chemicals Corporation, developed product name: X1248 ): 5.3 parts by weight Antifoaming agent (oil compound type, manufactured by San Nopco, product name: SN deformer 777): 0.02 parts by weight Dispersion stabilizer dispersion stabilizer (manufactured by San Nopco, product name: Roma PWA) -40): 0.04 parts by weight Water: 77 parts by weight The isocyanate group of the blocked isocyanate compound in the intermediate layer coating solution is the resin activity. The inorganic oxide fine particles (P) have a weight ratio (P / R) of 8/2 to the cross-linked resin (total of blocked isocyanate compound and resin: R) at a molar ratio of 1.6 to the functional hydrogen-containing group. )Met.

(Comparative Example 6)
A photoreceptor of Comparative Example 6 was produced in the same manner as in Example 11 except that the intermediate layer coating solution (organic solvent type, no curing agent) was prepared with the following components.
Titanium oxide fine particles as inorganic oxide fine particles (shape: dendritic, 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): 8 weight Part Copolymer nylon as a resin (product name: Amilan CM8000, manufactured by Toray Industries, Inc.): 2 parts by weight Methanol: 50 parts by weight 1,3-dioxolane: 40 parts by weight

(Comparative Example 7)
Comparative Example 6 was used except that the crystalline oxotitanium phthalocyanine (crystal 2) showing the diffraction peak of FIG. 5 was used as the charge generating material instead of the crystalline oxotitanium phthalocyanine showing the diffraction peak of FIG. A photoconductor of Comparative Example 7 was produced.

(Comparative Example 8)
A photoconductor of Comparative Example 8 was produced in the same manner as Example 11 except that the intermediate layer coating solution (aqueous, no curing agent) was prepared with the following components.
Titanium oxide fine particles as inorganic oxide fine particles (shape: dendritic, 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): 8 weight Part Polyvinyl acetal resin of water-based polyol as resin (solid content: 20%, OH value: 570, manufactured by Sekisui Chemical Co., Ltd., product name: ESREC K KW-3): 10 parts by weight Water: 82 parts by weight

(Comparative Example 9)
A photoconductor of Comparative Example 9 was produced in the same manner as in Example 11 except that X-type metal oxotitanium phthalocyanine was used as the charge generation material instead of the crystalline oxotitanium phthalocyanine showing the diffraction peak of FIG. .

(Comparative Example 10)
As a charge generation material, the trisazo pigment represented by the structural formula (2) was used in place of the crystalline oxotitanium phthalocyanine having the diffraction peak of FIG. A photoconductor was prepared.

  Table 2 summarizes the charge generation material of the charge generation layer and the formation material of the intermediate layer in Examples 11 to 28 and Comparative Examples 6 to 10.

(Evaluation)
(1) Electrical characteristics and environmental stability of photoconductor Instead of a commercially available digital copying machine (manufactured by Sharp Corporation, model: AR-F330), a commercially available digital copying machine (manufactured by Sharp Corporation, model: MX-3100) The photoconductors obtained in Examples 11 to 28 and Comparative Examples 6 to 10 were evaluated in the same manner as in the above (Evaluation) (1) except that was used.
The obtained results are shown in Table 3. In Table 3, the solvent used for the intermediate layer coating solution is additionally shown.

(2) Pot Life The photoconductors obtained in Examples 11 to 28 and Comparative Examples 6 to 10 were evaluated in the same manner as in the above (Evaluation) (2).
The obtained results are shown in Table 3.

From the results of Tables 2 and 3, the following can be understood.
(1) The photoreceptor of the present invention (Examples 11 to 28) is a polyamide-based binder that is widely used in current photoreceptors, even though water is used as a solvent for the intermediate layer coating solution. Compared with the photoreceptors of organic solvent-based comparative examples 6 and 7 using resin, all of the electrical characteristics, environmental stability, fatigue characteristics, and coating liquid stability (pot life) have equal or better performance. Yes.
(2) On the photoconductor (Comparative Examples 6 and 7) having an intermediate layer formed using an intermediate layer coating solution (organic solvent type, no curing agent), a memory image is observed. No memory image is observed on the body (Examples 11 to 28).
(3) In the photoreceptor (Comparative Example 8) having the intermediate layer formed using the intermediate layer coating solution (aqueous, no curing agent), the environmental characteristics are extremely deteriorated.
(4) Photoconductors (Comparative Examples 9 and 10) each having a charge generation layer formed using an X-type metal oxotitanium phthalocyanine and a trisazo pigment as charge generation materials are obtained from the photoconductors of the present invention (Examples 11 to 28). The sensitivity was low and VL was high.

(5) When the amount of the blocked isocyanate compound relative to the resin is small, that is, when the NCO group is small relative to the OH group in the resin (Examples 25 and 26), the proportion of OH groups (hydrophilic groups) in the layer increases. As a result, the environmental stability of the photoreceptor decreases.
On the other hand, when the amount of the blocked isocyanate compound relative to the resin is large, that is, when the NCO group relative to the OH group in the resin is large (Examples 27 and 28), the environmental characteristics do not deteriorate so much, but the fatigue characteristics and storage of the coating liquid are not. Sexuality decreases. This is presumably because an excess of isocyanate groups reacted with moisture to generate impurities that affect electrical characteristics.

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

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

Claims (13)

Comprising an intermediate layer between the conductive support and the photosensitive layer;
Intermediate layer coating wherein the intermediate layer comprises a blocked isocyanate compound, a resin having two or more active hydrogen-containing groups capable of reacting with an isocyanate group in the blocked isocyanate compound, inorganic oxide fine particles, and an aqueous medium. It is a layer formed through thermosetting from a liquid,
The photosensitive layer is a single-layer type photosensitive layer containing at least a charge generation material and a charge transport material, or a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material in this order or reverse order. An electrophotographic photosensitive member, which is a laminated photosensitive layer, wherein the charge generating substance is oxotitanium phthalocyanine having a crystal structure.   The electrophotographic photoreceptor according to claim 1, wherein the active hydrogen-containing group is a hydroxyl group or an amide group.   The electrophotographic photoreceptor according to claim 1, wherein the isocyanate group is present in the blocked isocyanate compound at a molar ratio of 0.5 to 1.5 with respect to the active hydrogen-containing group.   The electrophotographic photoreceptor according to any one of claims 1 to 3, wherein the blocked isocyanate compound has a structure in which hexamethylene diisocyanate or isophorone diisocyanate is blocked with an oxime or lactam blocking agent.   5. The resin according to claim 1, wherein the resin is selected from a polyether polyol resin, a polyester polyol resin, a polyacryl polyol resin, a polyvinyl alcohol resin, a polyvinyl acetal resin, cellulose, and a polyamide resin. The electrophotographic photoreceptor described in 1.   The electrophotographic photosensitive member according to claim 1, wherein the inorganic oxide fine particles are fine particles of titanium oxide or zinc oxide.   The oxotitanium phthalocyanine having the crystal structure shows a diffraction peak at least at a Bragg angle (2θ ± 0.2 °) of 27.1 to 27.3 ° in an X-ray diffraction spectrum using a CuKα ray (1.541Å). The electrophotographic photosensitive member according to claim 1.   The oxotitanium phthalocyanine having the crystal structure has a maximum diffraction peak at a Bragg angle (2θ ± 0.2 °) of 9.4 ° in an X-ray diffraction spectrum using CuKα rays (1.541Å), at least 7. Diffraction peaks are shown at 3 °, 9.7 °, and 27.3 °, and 9.4 ° and 9.7 ° have distinct branching peaks, which are larger than the above 27.3 ° diffraction peaks. The electrophotographic photosensitive member according to claim 7, wherein   The oxotitanium phthalocyanine having the above crystal structure has a Bragg angle (2θ ± 0.2 °) of 9.5 °, 9.7 °, 11.7 ° in an X-ray diffraction spectrum using CuKα rays (1.541 °). The electrophotographic photosensitive member according to claim 7, which exhibits major diffraction peaks at 15.0 °, 23.5 °, 24.1 ° and 27.3 °.   The oxotitanium phthalocyanine having the above crystal structure has a Bragg angle (2θ ± 0.2 °) of 9.0 °, 14.2 °, 23.9 ° in an X-ray diffraction spectrum using CuKα rays (1.541Å). The electrophotographic photosensitive member according to claim 7, which exhibits a major diffraction peak at 27.1 °.   The oxotitanium phthalocyanine having the crystal structure shows a diffraction peak at least at a Bragg angle (2θ ± 0.2 °) of 28.5 to 28.7 ° in an X-ray diffraction spectrum using CuKα rays (1.541Å). The electrophotographic photosensitive member according to claim 1.   The oxotitanium phthalocyanine having the above crystal structure has a Bragg angle (2θ ± 0.2 °) of at least 7.6 °, 12.6 °, 16 in an X-ray diffraction spectrum using CuKα rays (1.541Å). The electrophotographic photosensitive member according to claim 11, which exhibits major diffraction peaks at 3 °, 22.5 °, 25.3 ° and 28.6 °.   The electrophotographic photosensitive member according to claim 1, a charging unit for charging the electrophotographic photosensitive member, and exposing the charged electrophotographic photosensitive member to form an electrostatic latent image. An exposure unit; a development unit that develops the electrostatic latent image formed by exposure to form a toner image; a transfer unit that transfers the toner image formed by development onto a recording medium; and the transferred unit Fixing means for fixing a toner image on the recording medium to form an image; cleaning means for removing and collecting toner remaining on the electrophotographic photosensitive member; and removing surface charges remaining on the electrophotographic photosensitive member. An image forming apparatus comprising at least a charge eliminating unit.

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