JP2005250029A - Method for manufacturing electrophotographic photoreceptor, electrophotographic photoreceptor, process cartridge, and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an electrophotographic photoreceptor having a charge transport layer of a thin film (14 to 19 μm) having high uniformity of a film thickness, an electrophotographic photoreceptor manufactured by the manufacturing method, a process cartridge having the electrophotographic photoreceptor, and an electrophotographic apparatus. <P>SOLUTION: A coating liquid for the charge transport layer contains a charge transport material, a polyarylate resin and a cyclic ether having a boiling point below 90°C. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing an electrophotographic photosensitive member, an electrophotographic photosensitive member, a process cartridge having an electrophotographic photosensitive member, and an electrophotographic apparatus.

  An electrophotographic photosensitive member (inorganic electrophotographic photosensitive member) using an inorganic photoconductive material such as selenium, zinc oxide, cadmium sulfide, or silicon in the photosensitive layer is in terms of sensitivity, thermal stability, moisture resistance, durability, and the like. It was not always satisfactory.

  In recent years, research and development of an electrophotographic photosensitive member (organic electrophotographic photosensitive member) using an organic photoconductive material as a photosensitive layer has been actively conducted in order to overcome the drawbacks of inorganic electrophotographic photosensitive members.

  The photosensitive layer of the organic electrophotographic photoreceptor is generally a laminated photosensitive layer that is functionally separated into a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. The charge generation layer and the charge transport layer are formed by applying a coating solution for each layer and drying.

  One technique for achieving high image quality of the electrophotographic apparatus from the characteristics of the electrophotographic photosensitive member is to reduce the thickness of the photosensitive layer of the electrophotographic photosensitive member. This is because by reducing the film thickness of the photosensitive layer, the electric field strength generated in the photosensitive layer at the time of forming the electrostatic latent image increases, and as a result, a sharp electrostatic latent image with little spread is obtained.

  In an electrophotographic photosensitive member having a multilayer photosensitive layer, the thickness of the charge transport layer is usually much smaller than that of the charge generation layer. This leads to higher image quality of photographic equipment.

  On the other hand, if the thickness of the charge transport layer is too thin, the electrostatic capacity of the electrophotographic photosensitive member is too large, and the amount of charge necessary to obtain a sufficient surface potential (dark part potential) increases. The partial potential increases, the contrast becomes insufficient, and it becomes difficult to achieve high image quality.

  From the above viewpoint, the specific preferable film thickness of the charge transport layer is 14 to 19 μm.

  The charge transport layer is often positioned as the surface layer of the electrophotographic photosensitive member. Therefore, when the charge transport layer is the surface layer of the electrophotographic photosensitive member, the charge transport layer is required to have high wear resistance. . In particular, when the thickness of the charge transport layer is relatively thin, 14 to 19 μm, higher wear resistance is required.

  In recent years, as a method for charging the surface of an electrophotographic photosensitive member, a contact charging method in which the surface of the electrophotographic photosensitive member is charged by applying a voltage to a contact charging member disposed in contact with the electrophotographic photosensitive member has become mainstream. It has become. Compared to non-contact charging methods such as the corona charging method, the contact charging method has much less ozone generation, and in the corona charging method, about 80% of the current flowing to the charger flows to the shield and is wasted. On the other hand, the contact charging method has an advantage that it is economical because there is no waste.

  In the contact charging method, a DC voltage superimposed with an AC voltage is applied to the contact charging member (AC / DC contact charging method: Japanese Patent Laid-Open No. 63-149668 (Patent Document 1)), and only the DC voltage is contacted. A method of applying to a charging member (DC contact charging method: Japanese Patent Application Laid-Open No. 07-064302 (Patent Document 2)) is roughly classified.

  The AC / DC contact charging method has an advantage of excellent charging uniformity as compared with the DC contact charging method. On the other hand, the amount of discharge current to the surface of the electrophotographic photosensitive member increases as the AC voltage is applied, and the electrophotography There is a drawback in that the amount of wear on the surface of the photoreceptor increases. Therefore, the DC contact charging method is preferable as a method for charging the surface of the electrophotographic photosensitive member having a relatively thin charge transport layer as the surface layer.

  When the DC contact charging method is used as a method for charging the surface of the electrophotographic photosensitive member, the charging uniformity is worse than when the AC / DC contact charging method is used, and the output image is poor (for example, on the halftone image). White spots) may occur.

  One of the causes of deterioration of charging uniformity is unevenness in the film thickness of the charge transport layer. If the thickness of the charge transport layer is uneven, the electrostatic capacity of the electrophotographic photoreceptor is uneven, and as a result, the surface potential of the electrophotographic photoreceptor is uneven (non-uniform charging).

  This non-uniform charging occurs remarkably when a DC contact charging method that does not have a potential leveling effect due to an AC voltage is employed. In particular, when an electrophotographic photosensitive member having a relatively thin charge transport layer is used, the degree of unevenness in capacitance due to unevenness in the film thickness of the charge transport layer is increased, and thus non-uniform charging occurs more significantly. It will be.

Therefore, the film thickness of the charge transport layer of the electrophotographic photosensitive member is required to be as uniform as possible. When the thickness of the charge transport layer is relatively thin, or when the DC contact charging method is adopted, the uniformity of the thickness of the charge transport layer is particularly required.
JP-A 63-149668 Japanese Patent Application Laid-Open No. 07-064302

  An object of the present invention is to provide a method for producing an electrophotographic photoreceptor having a charge transport layer of a thin film (14 to 19 μm) having a high film thickness uniformity, an electrophotographic photoreceptor produced by the production method, and the electrophotographic photoreceptor. To provide a process cartridge and an electrophotographic apparatus having the same.

The present invention is a method for producing an electrophotographic photosensitive member having a charge generation layer and a charge transport layer in this order on a support, wherein the charge transport layer has a thickness of 14 to 19 μm,
A charge transport layer coating solution coating step of coating a charge transport layer coating solution on the charge generation layer;
In a method for producing an electrophotographic photosensitive member, comprising: a charge transport layer coating solution drying step of drying the charge transport layer coating solution coated on the charge generation layer by the charge transport layer coating solution coating step.
The method for producing an electrophotographic photoreceptor, wherein the charge transport layer coating solution contains a charge transport material, a polyarylate resin, and a cyclic ether having a boiling point of 90 ° C. or less.

  The present invention also provides an electrophotographic photosensitive member manufactured by the above-described manufacturing method, a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

  According to the present invention, a method for producing an electrophotographic photosensitive member having a charge transport layer of a thin film (14 to 19 μm) with high film thickness uniformity, an electrophotographic photosensitive member produced by the production method, and the electrophotographic photosensitive member A process cartridge and an electrophotographic apparatus can be provided.

  First, the configuration of the electrophotographic photoreceptor of the present invention will be described.

  As described above, the electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor having a charge generation layer and a charge transport layer in this order on a support.

  As a support body, what is necessary is just to have electroconductivity (electroconductive support body), For example, metal (alloy-made) support bodies, such as aluminum, aluminum alloy, and stainless steel, can be used. Moreover, the said metal support body and plastic support body which have a layer in which aluminum, an aluminum alloy, an indium oxide tin oxide alloy etc. were formed into a film by vacuum deposition can also be used. In addition, a support in which conductive particles such as carbon black, tin oxide particles, titanium oxide particles, and silver particles are impregnated into plastic or paper together with an appropriate binder resin, or a plastic support having a conductive binder resin, etc. Can also be used. In addition, examples of the shape of the support include a cylindrical shape and a belt shape, and a cylindrical shape is preferable.

  The surface of the support may be subjected to cutting treatment, roughening treatment, alumite treatment, etc. for the purpose of preventing interference fringes due to scattering of laser light or the like.

  A conductive layer may be provided between the support and the charge generation layer or an intermediate layer to be described later for the purpose of preventing interference fringes due to scattering of laser light or the like and covering the scratches on the support.

  The conductive layer can be formed by dispersing conductive particles such as carbon black, metal particles, and metal oxide particles in a binder resin.

  The thickness of the conductive layer is preferably 5 to 40 μm, and more preferably 10 to 30 μm.

  Further, an intermediate layer having a barrier function or an adhesive function may be provided between the support or the conductive layer and the charge generation layer. The intermediate layer is formed for the purpose of improving the adhesion of the photosensitive layer, improving the coating property, improving the charge injection property from the support, and protecting the photosensitive layer from electrical breakdown.

  The intermediate layer is acrylic resin, allyl resin, alkyd resin, ethyl cellulose resin, ethylene-acrylic acid copolymer, epoxy resin, casein resin, silicone resin, gelatin resin, nylon, phenol resin, butyral resin, polyacrylate resin, polyacetal resin, polyamide Imide resin, polyamide resin, polyallyl ether resin, polyimide resin, polyurethane resin, polyester resin, polyethylene resin, polycarbonate resin, polystyrene resin, polysulfone resin, polyvinyl alcohol resin, polybutadiene resin, polypropylene resin, urea resin, etc. It can be formed using a material such as aluminum.

  The thickness of the intermediate layer is preferably 0.05 to 5 μm, and more preferably 0.3 to 1 μm.

  A charge generation layer is provided on the support, conductive layer or intermediate layer.

  The charge generation layer can be formed by applying and drying a charge generation layer coating solution obtained by dispersing a charge generation material together with a binder resin and a solvent. Examples of the dispersion method include a method using a homogenizer, an ultrasonic disperser, a ball mill, a sand mill, a roll mill, a vibration mill, an attritor, a liquid collision type high-speed disperser, and the like. The ratio between the charge generating material and the binder resin is preferably in the range of 1: 0.1 to 1:10 (mass ratio), and more preferably in the range of 1: 1 to 3: 1 (mass ratio).

  Examples of the charge generating material include azo pigments such as monoazo, disazo, and trisazo, phthalocyanine pigments such as metal phthalocyanine and nonmetal phthalocyanine, indigo pigments such as indigo and thioindigo, and perylene acid anhydride and perylene imide. Perylene pigments, polycyclic quinone pigments such as anthraquinone and pyrenequinone, squarylium dyes, pyrylium salts and thiapyrylium salts, triphenylmethane dyes, inorganic substances such as selenium, selenium-tellurium, amorphous silicon, quinacridone pigments, And azurenium salt pigments, cyanine dyes, xanthene dyes, quinone imine dyes, styryl dyes, cadmium sulfide, and zinc oxide. These charge generation materials may be used alone or in combination of two or more.

  Examples of the binder resin used for the charge generation layer include acrylic resin, allyl resin, alkyd resin, epoxy resin, diallyl phthalate resin, silicone resin, styrene-butadiene copolymer, nylon, phenol resin, butyral resin, benzal resin, polyacrylate. Resin, Polyacetal resin, Polyamideimide resin, Polyamide resin, Polyallyl ether resin, Polyarylate resin, Polyimide resin, Polyurethane resin, Polyester resin, Polyethylene resin, Polycarbonate resin, Polystyrene resin, Polysulfone resin, Polyvinyl acetal resin, Polybutadiene resin, Polypropylene Resins, methacrylic resins, urea resins, vinyl chloride-vinyl acetate copolymers, vinyl acetate resins and the like. In particular, a butyral resin is preferable. These can be used singly or in combination of two or more as a mixture or copolymer.

  The solvent used in the coating solution for the charge generation layer is selected from the solubility and dispersion stability of the binder resin and charge generation material used, and the organic solvents include alcohols, sulfoxides, ketones, ethers, esters, aliphatic halogens. Hydrocarbons and aromatic compounds.

  The thickness of the charge generation layer is preferably 5 μm or less, and more preferably 0.1 to 2 μm.

  In addition, various sensitizers, antioxidants, ultraviolet absorbers, plasticizers, and the like can be added to the charge generation layer as necessary.

  A charge transport layer is provided on the charge generation layer.

  The charge transport layer can be formed by applying and drying a charge transport layer coating solution obtained by dissolving a charge transport material and a binder resin in a solvent. The ratio between the charge transport material and the binder resin is preferably in the range of 2: 1 to 1: 2 (mass ratio).

  In the present invention, the film thickness of the charge transport layer is 14 to 19 μm from the viewpoint of high image quality.

  Examples of the charge transport material include triarylamine compounds, hydrazone compounds, styryl compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, and triarylmethane compounds. These charge transport materials may be used alone or in combination of two or more.

  In the present invention, at least one binder resin used in the charge transport layer coating solution (binder resin used in the charge transport layer) is a polyarylate resin. Polyarylate resin is a resin having high wear resistance among thermoplastic resins, and is suitable as a binder resin for a charge transport layer.

  The polyarylate resin is preferably a polyarylate resin having a repeating structural unit represented by the following formula (1).

In said formula (1), R < ¹⁰¹ > -R < ¹¹² > shows a hydrogen atom or a substituted or unsubstituted alkyl group each independently. X ¹⁰¹ represents a single bond or —CR ¹¹³ R ¹¹⁴ —. When X ¹⁰¹ is —CR ¹¹³ R ¹¹⁴ —, R ¹¹³ and R ¹¹⁴ each independently represent a hydrogen atom or a substituted or unsubstituted alkyl group, or R ¹¹³ and R ¹¹⁴ are bonded to each other. The substituted or unsubstituted cycloalkylidene group formed is shown.

  Below, the suitable example of the repeating structural unit shown by the said Formula (1) is shown.

  From the viewpoint of wear resistance, the viscosity average molecular weight of the polyarylate resin is preferably 15,000 to 80,000.

  In the present invention, the viscosity average molecular weight was calculated as follows.

  That is, 0.5 g of a sample for molecular weight measurement is dissolved in 100 ml of methylene chloride, and the specific viscosity at 25 ° C. is measured using a modified Ubbelohde viscometer. The intrinsic viscosity is determined from this specific viscosity, and the average molecular weight is calculated from the viscosity equation of Mark-Houwink. The viscosity average molecular weight was a polystyrene conversion value measured by GPC (gel permeation chromatography).

  In addition, as long as the effect of the present invention is not impaired, a resin other than the polyarylate resin may be used in combination as the binder resin for the charge transport layer. Examples of resins other than polyarylate resin include acrylic resin, acrylonitrile resin, allyl resin, alkyd resin, epoxy resin, silicone resin, nylon, phenol resin, phenoxy resin, butyral resin, polyacrylamide resin, polyacetal resin, and polyamideimide resin. , Polyamide resin, polyallyl ether resin, polyimide resin, polyurethane resin, polyester resin, polyethylene resin, polycarbonate resin, polystyrene resin, polystyrene resin, polysulfone resin, polyvinyl butyral resin, polyphenylene oxide resin, polybutadiene resin, polypropylene resin, methacrylic resin, Examples include urea resin, vinyl chloride resin, and vinyl acetate resin. In addition, as a binder resin for the charge transport layer, when a polyarylate resin and other resins are used in combination, the content of the polyarylate resin in the charge transport layer is based on the total mass of the binder resin in the charge transport layer. It is preferably 50% by mass or more, and more preferably 80% by mass or more.

  By using a highly wear-resistant polyarylate resin as the binder resin for the charge transport layer, even if the charge transport layer is relatively thin (14 to 19 μm), the electrophotographic photosensitive member has a sufficiently high wear resistance. Sex can be secured.

  However, the polyarylate resin has a relatively low solubility in a solvent, and depending on the type of the solvent, it is difficult to prepare a coating solution for a charge transport layer that can form a charge transport layer with small film thickness unevenness.

  From the above viewpoint, in the present invention, at least one of the solvents used in the charge transport layer coating solution is a cyclic ether having a boiling point (boiling point under 1 atm) of 90 ° C. or less. Examples of the cyclic ether having a boiling point of 90 ° C. or lower include tetrahydrofuran (boiling point: 66 ° C.), 1,3-dioxolane (boiling point: 78 ° C.), oxane (boiling point: 88 ° C.), and the like.

  If the solvent of the coating solution for charge transport layer is a cyclic ether having a boiling point of 90 ° C. or less, dripping after coating the coating solution for charge transport layer can be suppressed, and thus the charge transport layer having small film thickness unevenness. Can be formed.

  However, since the cyclic ether used as the solvent for the coating solution for the charge transport layer in the present invention has a boiling point of 90 ° C. or less, depending on the environment in which the charge transport layer is formed, rapid evaporation occurs, and the surface of the charge transport layer May whiten (brush). This whitening can be confirmed as fine bubbles when the surface of the charge transport layer is enlarged and observed. In order to suppress the whitening phenomenon, it is necessary to control the temperature and humidity in a narrow range and / or to heat the object to be coated.

  The present inventors have intensively studied to suppress the whitening phenomenon from the viewpoint of the solvent of the coating solution for the charge transport layer. As a solvent for the coating solution for the charge transport layer, a cyclic ether having a boiling point of 90 ° C. or less and a substituent are used. It has been found that the whitening phenomenon can be suppressed by using in combination with aromatic hydrocarbons. Examples of the substituent that the aromatic hydrocarbon has include an alkyl group such as a methyl group and an ethyl group, and an alkoxy group such as a methoxy group and an ethoxy group.

  The boiling point of the aromatic hydrocarbon having a substituent used in combination with a cyclic ether having a boiling point of 90 ° C. or lower is preferably higher than the boiling point of the cyclic ether having a boiling point of 90 ° C. or lower and lower than 200 ° C. Is more preferably 130 to 150 ° C. If the boiling point of the aromatic hydrocarbon having a substituent used in combination with a cyclic ether having a boiling point of 90 ° C. or lower is too high, the aromatic hydrocarbon having the substituent in the charge transport layer after the coating liquid drying step for the charge transport layer Is likely to remain, which may adversely affect electrophotographic characteristics. On the other hand, if the boiling point of the aromatic hydrocarbon having the substituent is too low, the whitening phenomenon suppressing effect due to the cyclic ether having a boiling point of 90 ° C. or lower and the high sensitivity effect described below may not be sufficiently obtained.

  Examples of the aromatic hydrocarbon having a substituent that satisfies the above conditions include toluene (boiling point: 110.6 ° C.), xylene (o-xylene (boiling point: 144.4 ° C.)), m-xylene (boiling point: 139. 1 ° C), p-xylene (boiling point: 138.4 ° C)), ethylbenzene (boiling point: 136.25 ° C), anisole (boiling point: 153.8 ° C), and the like. Among these, xylene (o-xylene, m-xylene, p-xylene) and ethylbenzene are preferable.

  By using a cyclic ether having a boiling point of 90 ° C. or less and an aromatic hydrocarbon having a substituent, the reason why the whitening phenomenon caused by the cyclic ether having a boiling point of 90 ° C. or less can be suppressed is as follows. This is probably because the aromatic hydrocarbon having a boiling point is generally higher than 90 ° C., so that rapid evaporation of the cyclic ether can be suppressed.

  In addition, high sensitivity can be achieved by using a combination of a cyclic ether having a boiling point of 90 ° C. or less and an aromatic hydrocarbon having a substituent. This is because the aromatic hydrocarbon having a substituent whose evaporation is slower than that of a cyclic ether having a boiling point of 90 ° C. or lower can sufficiently wet the lower charge generation layer, and therefore, a large area charge generation layer-charge This is probably because the transport layer interface can be formed.

  In addition, even if the solvent has a boiling point higher than 90 ° C., cyclohexanone (boiling point: 155 ° C.), acetylacetone (boiling point: 140 ° C.) Not obtained with non-aromatic hydrocarbons such as .5 ° C).

  When using a cyclic ether having a boiling point of 90 ° C. or less and an aromatic hydrocarbon having a substituent as a solvent for the coating solution for the charge transport layer, the aromatic carbon having a cyclic ether having a boiling point of 90 ° C. or less and a substituent. The ratio with hydrogen is preferably in the range of 1: 9 to 9: 1 (mass ratio), and more preferably in the range of 3: 7 to 7: 3 (mass ratio).

In addition, cyclic ethers are often chemically unstable. Therefore, in order to improve the liquid stability of the charge transport layer coating liquid, the charge transport layer coating liquid may contain an antioxidant as a liquid stabilizer. Examples of the antioxidant contained in the charge transport layer coating solution include compounds having a hindered phenol structure and / or a hindered amine structure, phosphorus atom-containing organic compounds, sulfur atom-containing organic compounds, hydroquinone and derivatives thereof. It is done. Among these, a compound having a hindered phenol structure is preferable from the viewpoint of both the liquid stability of the coating solution for the charge transport layer and the electrophotographic characteristics (repetitive characteristics, potential stability).
・ Examples of compounds having a hindered phenol structure

・ Examples of compounds having hindered amine structural units

・ Examples of phosphorus-containing organic compounds

・ Examples of organic compounds containing sulfur atoms

・ Examples of hydroquinone and its derivatives

  The content of the antioxidant in the charge transport layer coating solution is preferably 0.001% by mass or less with respect to the cyclic ether in the charge transport layer coating solution.

  When applying the coating liquid for each of the above layers, for example, a coating method such as a dip coating method (dip coating method), a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, a blade coating method, or the like should be used. Can do.

  FIG. 1 shows an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.

  In FIG. 1, reference numeral 1 denotes a cylindrical electrophotographic photosensitive member, which is rotationally driven in a direction of an arrow about a shaft 2 at a predetermined peripheral speed.

  The surface of the electrophotographic photosensitive member 1 that is rotationally driven is uniformly charged to a predetermined positive or negative potential by a charging unit (primary charging unit: charging roller or the like) 3, and then subjected to slit exposure, laser beam scanning exposure, or the like. Exposure light (image exposure light) 4 output from exposure means (not shown) is received. In this way, electrostatic latent images corresponding to the target image are sequentially formed on the surface of the electrophotographic photosensitive member 1.

  The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is developed with toner contained in the developer of the developing means 5 to become a toner image. Next, the toner image formed and supported on the surface of the electrophotographic photoreceptor 1 is transferred from a transfer material supply means (not shown) to the electrophotographic photoreceptor 1 and the transfer means by a transfer bias from a transfer means (transfer roller or the like) 6. 6 (contact portion) is sequentially transferred onto a transfer material (paper or the like) P taken out and fed in synchronization with the rotation of the electrophotographic photosensitive member 1.

  The transfer material P that has received the transfer of the toner image is separated from the surface of the electrophotographic photosensitive member 1 and introduced into the fixing means 8 to receive the image fixing, and is printed out as an image formed product (print, copy). Is done.

  The surface of the electrophotographic photosensitive member 1 after the transfer of the toner image is cleaned by a cleaning means (cleaning blade or the like) 7 to remove the developer (toner) remaining after transfer, and further from a pre-exposure means (not shown). After being subjected to charge removal processing by pre-exposure light (not shown), it is repeatedly used for image formation. As shown in FIG. 1, when the charging unit 3 is a contact charging unit using a charging roller or the like, pre-exposure is not necessarily required.

  Among the above-described components such as the electrophotographic photosensitive member 1, the charging unit 3, the developing unit 5, the transfer unit 6 and the cleaning unit 7, a plurality of components are housed in a container and integrally combined as a process cartridge. The process cartridge may be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. In FIG. 1, an electrophotographic photosensitive member 1, a charging unit 3, a developing unit 5 and a cleaning unit 7 are integrally supported to form a cartridge, and an electrophotographic apparatus is provided using a guide unit 10 such as a rail of the electrophotographic apparatus main body. The process cartridge 9 is detachable from the main body.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to these. In the examples, “part” means “part by mass”. In addition, all the polyarylate resins used in Examples and Comparative Examples have a molar ratio of terephthalic acid structure to isophthalic acid structure (terephthalic acid structure: isophthalic acid structure) of 50:50. Further, unless otherwise specified, the film thickness is the film thickness at the central part (central ± 30 mm) in the longitudinal direction of the electrophotographic photosensitive member.

(Example 1)
An aluminum cylinder having a diameter of 30 mm and a length of 357 mm was used as a support (cylindrical support).

Next, SnO ₂ coat-treated barium sulfate (conductive particles) 10 parts, titanium oxide (for resistance adjustment) 2 parts, phenol resin 6 parts, silicone oil (leveling agent) 0.001 part, and methanol 4 parts / methoxy A mixed solvent of 16 parts of propanol was dispersed in a sand mill apparatus using glass beads having a diameter of 1 mm for 2 hours to prepare a coating solution for a conductive layer.

  This conductive layer coating solution is dip coated on a support in a normal temperature and normal humidity (23 ° C./60% RH) environment and thermally cured at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 15 μm. did.

  Next, 3 parts of N-methoxymethylated nylon and 3 parts of copolymer nylon were dissolved in a mixed solvent of 65 parts of methanol / 30 parts of n-butanol to prepare an intermediate layer coating solution.

  This intermediate layer coating solution was dip coated on the conductive layer and dried at 80 ° C. for 10 minutes to form an intermediate layer having a thickness of 0.5 μm.

  Next, crystalline oxytitanium phthalocyanine having strong peaks at 9.0 °, 14.2 °, 23.9 °, and 27.1 ° of the Bragg angle (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction 4 parts of crystals (charge generation material), 2 parts of polyvinyl butyral resin (trade name: ESREC BM2, manufactured by Sekisui Chemical Co., Ltd.) and 60 parts of cyclohexanone are dispersed in a sand mill using glass beads having a diameter of 1 mm for 4 hours. A coating solution for charge generation layer was prepared by adding 100 parts of ethyl acetate.

  This charge generation layer coating solution was dip coated on the intermediate layer and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.

  Next, 5.6 parts of an amine compound (charge transport material) having a structure represented by the following formula (3),

1.4 parts of an amine compound (charge transport material) having a structure represented by the following formula (4),

9 parts of a polyarylate resin (homopolymer, viscosity average molecular weight: 40000) having a repeating structural unit represented by the above formula (1-3) is dissolved in a mixed solvent of 45 parts of tetrahydrofuran / 45 parts of p-xylene. Thus, a charge transport layer coating solution was prepared.

  This charge transport layer coating solution was dip coated on the charge generation layer and dried at 120 ° C. for 30 minutes to form a charge transport layer having a thickness of 15 μm.

  In this manner, an electrophotographic photoreceptor having a charge transport layer as a surface layer was produced.

  In addition, all the solvents of the coating liquid for charge transport layers used in the examples and comparative examples are special grades manufactured by Kishida Chemical Co., Ltd.

  The produced electrophotographic photosensitive member was mounted on a color laser printer (trade name: LBP-2810, DC contact charging method) manufactured by Canon Inc.

  First, a halftone (HT) image (printing of one dot for every two spaces in the main scanning / sub-scanning directions) was output with the pre-exposed light emitting portion of the LBP-2810 main body shielded from light (initial).

  Next, an endurance test was performed in which the operation of outputting a character image with a printing rate of 1% on A4 paper in landscape orientation was repeated every 10 seconds with the pre-exposed light-emitting part of the LBP-2810 main body shielded, and output 20000 sheets. It was.

  After the durability test, a solid white image was output in a state where the pre-exposed light emitting portion of the LBP-2810 main body was shielded from light.

  The halftone image output in the initial stage and the solid white image output after the durability test were evaluated.

  The developing device was removed, and a potential probe was attached thereto, and the dark portion potential Vd (no laser exposure) and the bright portion potential Vl (laser overall exposure) on the surface of the electrophotographic photosensitive member at the development position were also measured (initially, Both after the endurance test).

  The LBP-2810 is an electrophotographic apparatus in which four process cartridges (each having an electrophotographic photosensitive member and a DC contact charging method charging means) are mounted. Only (for cyan) was performed with a process cartridge installed. The process cartridge presence / absence detection is always fixed to “present”.

  The evaluation results are shown in Table 2.

(Example 2)
In Example 1, except that 45 parts of tetrahydrofuran in the coating solution for the charge transport layer was changed to 45 parts of oxane, 45 parts of p-xylene was changed to 45 parts of ethylbenzene, and the film thickness of the charge transport layer was changed to 14 μm. An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 3)
In Example 1, 45 parts of tetrahydrofuran in the charge transport layer coating solution was changed to 45 parts of 1,3-dioxolane, 45 parts of p-xylene was changed to 45 parts of m-xylene, and the film thickness of the charge transport layer was changed. An electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the thickness was 19 μm. The evaluation results are shown in Table 2.

Example 4
In Example 1, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that 45 parts of p-xylene in the coating solution for charge transport layer was changed to 45 parts of o-xylene. The evaluation results are shown in Table 2.

(Example 5)
In Example 1, 9 parts of a polyarylate resin in the charge transport layer coating solution is 9 parts of a polyarylate resin having a repeating structural unit represented by the above formula (1-2) (homopolymer, viscosity average molecular weight: 40000). And 5.6 parts of the amine compound having the structure represented by the above formula (3) is changed to 5.6 parts of an amine compound (charge transporting material) having the structure represented by the following formula (5). An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that 45 parts of xylene were changed to 45 parts of o-xylene. The evaluation results are shown in Table 2.

(Example 6)
In Example 5, 9 parts of polyarylate resin in the coating solution for charge transport layer is polyarylate resin having a repeating structural unit represented by the above formula (1-2) (homopolymer, viscosity average molecular weight: 40000) 7. 2 parts, a repeating structural unit represented by the following formula (6-1), a repeating structural unit represented by the following formula (6-2), and a polycarbonate resin having a repeating structural unit represented by the following formula (6-3) Polymer, copolymer ratio (6-1) :( 6-2) :( 6-3) = 7: 2: 1 (molar ratio), viscosity average molecular weight: 40000) 1.8 parts resin mixture (total An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 5 except that the change was made to 9 parts). The evaluation results are shown in Table 2.

(Example 7)
In Example 6, the resin mixture (total 9 parts) of the polyarylate resin and the polycarbonate resin in the coating solution for the charge transport layer was added to the polyarylate resin (single weight) having the repeating structural unit represented by the above formula (1-3). The electrophotographic photosensitive member was prepared in the same manner as in Example 6 except that 9 parts by weight, viscosity average molecular weight: 40000), 45 parts by weight of tetrahydrofuran were changed to 90 parts by weight, and o-xylene was not used. evaluated. The evaluation results are shown in Table 2.

(Example 8)
In Example 6, the resin mixture (total 9 parts) of the polyarylate resin and the polycarbonate resin in the coating solution for the charge transport layer was added to the polyarylate resin (single weight) having the repeating structural unit represented by the above formula (1-3). The electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 6 except that the blending was changed to 9 parts (viscosity average molecular weight: 40000) and 45 parts of o-xylene was changed to 45 parts of acetylacetone. The evaluation results are shown in Table 2.

Example 9
In Example 8, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 8 except that 45 parts of acetylacetone in the coating solution for charge transport layer was changed to 45 parts of benzyl alcohol. The evaluation results are shown in Table 2.

(Example 10)
In Example 9, 9 parts of polyarylate resin in the charge transport layer coating solution is 9 parts of polyarylate resin having a repeating structural unit represented by the above formula (1-6) (homopolymer, viscosity average molecular weight: 40000) And 5.6 parts of the amine compound having the structure represented by the above formula (5) is changed to 5.6 parts of an amine compound (charge transport material) having the structure represented by the following formula (7). 1.4 parts of the amine compound having the structure represented by (4) is changed to 1.4 parts of an amine compound (charge transport material) having the structure represented by the following formula (8), and 45 parts of benzyl alcohol is replaced with 45 parts of toluene. An electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 9 except that the above was changed. The evaluation results are shown in Table 2.

(Comparative Example 1)
In Example 1, 9 parts of polyarylate resin in the coating solution for charge transport layer was changed to polycarbonate resin (trade name: Z-200) manufactured by Mitsubishi Engineering Plastics Co., Ltd. An electrophotographic photoreceptor was prepared and evaluated. The evaluation results are shown in Table 2.

(Comparative Example 2)
In Example 1, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the thickness of the charge transport layer was changed to 20 μm. The evaluation results are shown in Table 2.

(Comparative Example 3)
In Example 1, an electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the thickness of the charge transport layer was 13 μm. The evaluation results are shown in Table 2.

(Comparative Example 4)
In Example 1, an electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that 45 parts of tetrahydrofuran in the coating solution for charge transport layer was changed to 45 parts of 1,4-dioxane (boiling point: 101.1 ° C.). Prepared and evaluated. The evaluation results are shown in Table 2.

(Comparative Example 5)
In Example 1, charge was changed in the same manner as in Example 1 except that 45 parts of tetrahydrofuran in the coating solution for charge transport layer was changed to 45 parts of acetone (boiling point: 56.1 to 56.5 ° C., acyclic ether). When the coating liquid for the transport layer was prepared, the coating liquid became cloudy due to poor dissolution of the binder resin, so that the coating was not performed.

(Comparative Example 6)
In Example 1, the charge transport layer coating was performed in the same manner as in Example 1 except that 45 parts of tetrahydrofuran in the charge transport layer coating solution was changed to 45 parts of methyl ethyl ketone (boiling point: 79.6 ° C., acyclic ether). When the solution was prepared, the coating solution became cloudy due to poor dissolution of the binder resin, and thus the coating was not performed.

  The conditions of the charge transport layer (charge transport layer coating solution) of Examples 1 to 10 and Comparative Examples 1 to 6 are summarized in Table 1.

1 is a diagram illustrating an example of a schematic configuration of an electrophotographic apparatus including a process cartridge having the electrophotographic photosensitive member of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Axis 3 Charging means 4 Exposure light 5 Developing means 6 Transfer means 7 Cleaning means 8 Fixing means 9 Process cartridge 10 Guide means P Transfer material

Claims (12)

A method for producing an electrophotographic photosensitive member having a charge generation layer and a charge transport layer in this order on a support, wherein the charge transport layer has a thickness of 14 to 19 μm,
A charge transport layer coating solution coating step for coating a charge transport layer coating solution on the charge generation layer;
In a method for producing an electrophotographic photosensitive member, comprising: a charge transport layer coating solution drying step of drying the charge transport layer coating solution coated on the charge generation layer by the charge transport layer coating solution coating step.
The method for producing an electrophotographic photosensitive member, wherein the coating liquid for charge transport layer contains a charge transport material, a polyarylate resin, and a cyclic ether having a boiling point of 90 ° C. or less.   2. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the cyclic ether is at least one cyclic ether selected from the group consisting of tetrahydrofuran, 1,3-dioxolane and oxane.   The method for producing an electrophotographic photosensitive member according to claim 1, wherein the coating liquid for charge transport layer contains an aromatic hydrocarbon having a substituent.   4. The method for producing an electrophotographic photosensitive member according to claim 3, wherein the aromatic hydrocarbon having a substituent is at least one of xylene and ethylbenzene.   The method for producing an electrophotographic photosensitive member according to claim 1, wherein the charge transport layer is a surface layer of the electrophotographic photosensitive member.   It has a charge generation layer and a charge transport layer on a support in this order, and the film thickness of the charge transport layer is 14 to 19 μm, and is manufactured by the manufacturing method according to claim 1. An electrophotographic photosensitive member.   The electrophotographic photosensitive member according to claim 6, wherein the charge transport layer is a surface layer of the electrophotographic photosensitive member.   8. The electrophotographic photosensitive member according to claim 6 and at least one means selected from the group consisting of a charging means, a developing means, a transfer means and a cleaning means are integrally supported and detachably attached to the main body of the electrophotographic apparatus. Process cartridge characterized by being.   9. The process cartridge according to claim 8, comprising at least the electrophotographic photosensitive member and the charging unit, and the charging unit includes a contact charging member disposed in contact with the electrophotographic photosensitive member.   An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 6, a charging unit, an exposure unit, a developing unit, and a transfer unit.   The electrophotographic apparatus according to claim 10, wherein the charging unit includes a contact charging member disposed in contact with the electrophotographic photosensitive member. The electrophotographic apparatus according to claim 11, further comprising a voltage applying unit configured to apply only a direct current voltage to the contact charging member.

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