JP2012220880A - Electrophotographic photoreceptor, process cartridge and electrophotographic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor in which a friction coefficient between the surface of the electrophotographic photoreceptor and a cleaning blade is hard to increase even in a repeated use, and a process cartridge and an electrophotographic apparatus having the electrophotographic photoreceptor.SOLUTION: The surface of an electrophotographic photoreceptor is coated with a fluorine-based composition containing (i) fluorine-based oil, or fluorine-based grease comprising fluorine-based base oil and fluorine-based thickener and (ii) spherical inorganic fine particles.

Description

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

  Conventionally, image formation using an electrophotographic process in which toner is supplied to an electrostatic latent image formed on the surface of an electrophotographic photosensitive member to form a toner image, and this toner image is transferred to a transfer material such as paper. Devices, so-called electrophotographic devices are provided.

  In an electrophotographic apparatus, it is difficult to transfer all the toner from the surface of the electrophotographic photosensitive member to the transfer material during transfer, and it is inevitable that some toner remains on the surface of the electrophotographic photosensitive member. . For this reason, it is necessary to sufficiently remove the toner (transfer residual toner) remaining on the surface of the electrophotographic photosensitive member without being transferred to the transfer material.

  Various methods have been proposed for removing the transfer residual toner, and a method using a cleaning blade made of an elastic material such as urethane rubber is well known. The method using the cleaning blade is a method of scraping off the transfer residual toner by bringing the cleaning blade into contact with the surface of the electrophotographic photosensitive member on the downstream side of the transfer portion in the rotation direction of the electrophotographic photosensitive member. The cleaning means (means for removing the transfer residual toner) using this method is widely used because it has advantages such as a simple structure, small size, and low cost.

  At this time, in order to reduce the friction coefficient between the surface of the electrophotographic photosensitive member and the cleaning blade, the electrophotographic photosensitive member is provided with a surface layer in which tetrafluoroethylene particles are dispersed in the binder resin, or the cleaning blade is lubricated. For example, a fluorinated graphite powder as an agent is applied (Patent Document 1).

Japanese Patent Laid-Open No. 2-287383

  In order to form an electrostatic latent image on the surface of the electrophotographic photosensitive member, the surface of the electrophotographic photosensitive member is brought to a predetermined potential by a contact charging method or a corona charging method charging means before receiving image exposure light. It must be charged.

  However, the discharge that occurs during the charging tends to cause denaturation of the material on the surface of the electrophotographic photosensitive member. For example, in a method in which a surface layer formed by dispersing tetrafluoroethylene particles in a binder resin is provided on an electrophotographic photoreceptor, the binder resin of the surface layer is likely to deteriorate due to repeated use. Further, in the method of applying the fluorinated graphite powder to the cleaning blade, the fluorinated graphite powder tends to aggregate due to repeated use. In either case, repeated use may increase the coefficient of friction between the surface of the electrophotographic photosensitive member and the cleaning blade, which may cause the cleaning blade to curl (blade curling).

  An object of the present invention is to provide an electrophotographic photosensitive member that does not easily increase the coefficient of friction with a cleaning blade even after repeated use, and a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

  In the present invention, the surface is coated with a fluorine-based composition containing (i) fluorine-based oil, or fluorine-based grease comprising a fluorine-based base oil and a fluorine-based thickener, and (ii) spherical inorganic fine particles. An electrophotographic photosensitive member.

  In addition, the present invention provides an integrated electrophotographic photosensitive member, charging means for charging the surface of the electrophotographic photosensitive member, and cleaning means having a cleaning blade in contact with the surface of the electrophotographic photosensitive member. And a process cartridge that is detachably attached to the main body of the electrophotographic apparatus.

  The present invention also provides the electrophotographic photosensitive member, a charging unit for charging the surface of the electrophotographic photosensitive member, and image exposure light applied to the surface of the electrophotographic photosensitive member to irradiate the surface of the electrophotographic photosensitive member. Image exposing means for forming an electrostatic latent image on the surface; developing means for developing the electrostatic latent image with toner to form a toner image on the surface of the electrophotographic photosensitive member; and An electrophotographic apparatus comprising: transfer means for transferring from a surface of a body to a transfer material; and cleaning means having a cleaning blade in contact with the surface of the electrophotographic photosensitive member.

  According to the present invention, it is possible to provide an electrophotographic photosensitive member in which the coefficient of friction with the cleaning blade hardly increases even when used repeatedly, and a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

It is a figure which shows typically the state by which the surface of the electrophotographic photoreceptor is coated with the fluorine-based composition according to the present invention. 1 is a diagram illustrating a schematic configuration of an electrophotographic apparatus including a process cartridge having an electrophotographic photosensitive member.

  The electrophotographic photoreceptor of the present invention has a fluorine-based composition containing (i) fluorine-based oil or fluorine-based grease composed of a fluorine-based base oil and a fluorine-based thickener, and (ii) spherical inorganic fine particles. The surface is coated.

  FIG. 1 schematically shows a state in which the surface of an electrophotographic photoreceptor is coated with the fluorine-based composition according to the present invention. The surface of the electrophotographic photosensitive member 103 is coated with a fluorine-based composition containing fluorine grease 102 and spherical inorganic fine particles 101.

  When a concave shape such as a groove is formed on the surface of the electrophotographic photosensitive member, it may be coated so as to fill the concave shape.

  As the fluorine base oil for the fluorine grease, fluorine oil is preferably used. A fluorinated oil is an oily material containing fluorine atoms in the molecule. The fluorine-based oil preferably has high heat resistance, and a fluorine-based synthetic oil that can be used as a lubricating oil is preferable. Examples of the fluorine-based oil include fluorocarbon oil, perfluoroether oil, perfluoroalkyl ether oil, fluoroester oil, fluorine-modified paraffin oil, and fluorine-modified ester oil.

  As the fluorine-based thickener for the fluorine-based grease, a solid fluorine-based lubricant is preferably used. For example, polytetrafluoroethylene, polychlorotrifluoroethylene, a copolymer of tetrafluoroethylene and ethylene, and polyfluoride. Fluorine atom-containing resins such as vinylidene chloride, copolymers of tetrafluoroethylene and oxafluoropropylene, polychlorotrifluoroethylene, polytrifluorochloroethylene, dichlorodifluoroethylene, and polytrifluoroethylene.

From the viewpoint of ease of use of the fluorine-based grease, the ratio of the fluorine-based thickener in the fluorine-based grease is preferably 1 to 49% by mass, and 10 to 40% by mass with respect to the total mass of the fluorine-based grease. More preferably. When the ratio of the fluorinated thickener decreases, the fluidity of the fluorinated grease tends to increase, and when it increases, the tendency to become harder. From the same point of view, the consistency of the fluorine-based grease component is preferably NLGI number (NLGI consistency number) of No. 1 to No. 3 (No. 1, No. 2, or No. 3). In addition, if the kinematic viscosity of fluorine-type oil is 500 mm < ² > / s or more, it is not necessarily required to use a fluorine-type thickener together.

  The fluorine-based composition coated on the surface of the electrophotographic photoreceptor of the present invention is a fluorine-based material (a material containing fluorine atoms in the molecule) in which the grease component is a base oil (oil) and a thickener. Therefore, the fluorine-based composition according to the present invention can give high lubricity to the surface of the electrophotographic photosensitive member, and the deterioration of the material is small even when subjected to the discharge that occurs during charging, and the friction coefficient accompanying the material deterioration is small. The increase is suppressed.

As the spherical inorganic fine particles, spherical fine particles composed solely of inorganic components or spherical fine particles containing an inorganic component as a main component are preferably used. For example, silicon oxide such as SiO ₂ , aluminum oxide such as Al ₂ O ₃ And zinc oxides such as ZnO, titanium oxides such as TiO _2, and clay layered oxides such as natural mica and synthetic mica.

  Compared to organic fine particles, inorganic fine particles have less material deterioration due to discharge that occurs during charging, and an increase in the coefficient of friction associated with material deterioration is suppressed. In addition, inorganic fine particles are less crushed and deformed than organic fine particles such as styrene crosslinked particles and crosslinked rubber particles, and an increase in the friction coefficient associated with the crushed or deformed particles is also suppressed.

  Moreover, although the inorganic fine particles used for the fluorine-based composition according to the present invention are spherical, specifically, the average circularity is preferably 1.0 to 2.0, and preferably 1.0 to 1.5. It is more preferable that When the inorganic fine particles are not spherical, rolling friction between the surface of the electrophotographic photosensitive member and the cleaning blade is less likely to occur, and it is difficult to realize a reduction in the friction coefficient. Also, the coefficient of friction may be increased by scratching or destroying the electrophotographic photosensitive member or the cleaning blade. Here, the average circularity of the inorganic fine particles refers to an average value obtained by performing SEM observation of the inorganic fine particles and setting the longest diameter (a) / shortest diameter (b) of the inorganic fine particles as the circularity.

  The average particle size of the spherical inorganic fine particles is preferably from 0.1 to 5.0 μm, and more preferably from 0.3 to 3.0 μm. As the average particle size of the spherical inorganic fine particles decreases, the contact amount between the surface of the electrophotographic photosensitive member and the cleaning blade increases, and the friction coefficient between the surface of the electrophotographic photosensitive member and the cleaning blade tends to increase. When the average particle size of the spherical inorganic fine particles is increased, particularly when the average particle size is larger than the average particle size of the toner, the transfer residual toner tends to be difficult to be removed from the surface of the electrophotographic photosensitive member.

  By coating the surface of the electrophotographic photosensitive member with the fluorine-based composition according to the present invention, it is possible to obtain an electrophotographic photosensitive member in which the coefficient of friction with the cleaning blade hardly increases even when used repeatedly.

  If the fluorinated oil or the fluorinated grease is not used and only the spherical inorganic fine particles are coated on the surface of the electrophotographic photosensitive member alone, the surface of the electrophotographic photosensitive member and the cleaning blade are used in the initial stage of use. And the coefficient of friction is low. However, when repeatedly used, the spherical inorganic fine particles aggregate to cause no rolling friction, and the friction coefficient between the surface of the electrophotographic photosensitive member and the cleaning blade increases. In particular, when spherical inorganic fine particles having a high hardness are used, the surface of the electrophotographic photosensitive member is destroyed, which may further increase the friction coefficient.

  On the other hand, when a fluorine-based composition containing spherical inorganic fine particles and the above-mentioned fluorine-based oil or the above-mentioned fluorine-based grease is used while being coated on the surface of the electrophotographic photosensitive member as in the present invention, the fluorine-based oil or fluorine-based grease is used. As a result, the degree of rolling friction is smaller than when spherical inorganic fine particles are used alone. However, fluorinated oil and fluorinated grease are also materials that reduce the friction coefficient, and by combining with spherical inorganic fine particles, the friction coefficient is higher than when fluorinated oil or fluorinated grease is used alone. Can be reduced. In addition, fluorinated oil or fluorinated grease can suppress the aggregation of spherical inorganic fine particles. Furthermore, since any material is a material with little deterioration due to discharge, the increase in the coefficient of friction is suppressed even when used repeatedly. can do. Even when spherical inorganic fine particles having a high hardness are used, the surface of the electrophotographic photosensitive member is also prevented from being broken by the buffering action of the fluorinated oil or the fluorinated grease.

  The usage state of the fluorine-based composition according to the present invention is that the surface of the electrophotographic photosensitive member is coated with spherical inorganic fine particles at 10% or more, and fluorine oil or fluorine-based grease is 1 μm or less on the surface of the electrophotographic photosensitive member. It is preferable that the film is coated with a thickness (more preferably, a thickness of 0.1 μm or less). When the thickness of the fluorinated oil or fluorinated grease is reduced, the degree of rolling friction due to the spherical inorganic fine particles tends to be reduced.

When thinly coating the surface of an electrophotographic photosensitive member with fluorinated oil or fluorinated grease, for example, after being dispersed in a solvent as necessary, dip coating (dipping), spray coating, ink jet coating A coating method such as can be used. Further, when coating the surface of the electrophotographic photosensitive member with a fluorine-based composition, a fluorine-based composition containing fluorine-based oil or fluorine-based grease and spherical inorganic fine particles is prepared, and then this is applied to the electrophotographic photosensitive member. The surface of the electrophotographic photosensitive member may be separately coated with fluorine-based oil or fluorine-based grease and spherical inorganic fine particles, and a fluorine-based composition may be formed on the surface of the electrophotographic photosensitive member. Examples of the cleaning blade for the cleaning means include a blade made of a crosslinked rubber material such as urethane rubber or silicon rubber.

  Further, when the cleaning blade is brought into contact with the surface of the electrophotographic photosensitive member, it may be brought into contact with forward contact (with) or reverse contact (counter). The rotational speed of the electrophotographic photosensitive member having a cleaning blade in contact with the surface is preferably 100 to 1000 mm / s at the peripheral speed.

  As a charging means for charging the surface of the electrophotographic photosensitive member, a non-contact type or contact type charging device can be used. Examples of the non-contact type charging device include a corona charger. Examples of the contact-type charging device include a charging device having a charging roller, a charging brush, a charging blade, and a charging belt.

  In recent years, contact-type charging devices have been widely used. The reason for this is that the voltage of the power source can be lowered and the generation of ozone is very small. Specifically, a contact charging member such as a charging roller is brought into contact with the surface of the electrophotographic photosensitive member, and a positive or negative DC voltage of about several hundreds V to 2 kV, and in some cases an AC voltage is superimposed on the contact charging member. The surface of the electrophotographic photosensitive member is charged to several hundred to 1.5 kV.

  When a voltage obtained by superimposing an AC voltage on a DC voltage is applied to the contact charging member, if the amount of charge on the surface of the electrophotographic photosensitive member is insufficient, the contact charging member discharges to the electrophotographic photosensitive member, and the electrophotographic photosensitive member When the surface is excessively charged (charged to a potential higher than the DC voltage), the electrophotographic photosensitive member is discharged to the contact charging member. By repeating these two discharges by the frequency of the AC voltage, the surface potential of the electrophotographic photosensitive member converges to the value of the DC voltage.

  Hereinafter, the material and layer structure of the electrophotographic photoreceptor will be described by taking an organic photoreceptor using an organic photoconductive substance as an example.

  The electrophotographic photoreceptor basically has a support and a photosensitive layer formed on the support.

  The photosensitive layer may be a single-layer type photosensitive layer containing a charge transport material and a charge generation material in the same layer, or a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. It may be a laminated type (functionally separated type) photosensitive layer separated. From the viewpoint of electrophotographic characteristics, a laminated photosensitive layer is preferable. The laminated photosensitive layer has a normal layer type photosensitive layer laminated in the order of the charge generation layer and the charge transport layer from the support side, and a reverse layer type photosensitive layer laminated in the order of the charge transport layer and the charge generation layer from the support side. However, from the viewpoint of electrophotographic characteristics, a normal layer type photosensitive layer is preferable. In addition, the charge generation layer and the charge transport layer can each have a laminated structure.

  As the support, one having conductivity (conductive support) is preferable. For example, a support made of metal (made of alloy) such as aluminum, aluminum alloy, and stainless steel can be used. A metal support or a plastic support having a coating formed by vacuum deposition of aluminum, an aluminum alloy, an indium oxide-tin oxide alloy, or the like can also be used. It is also possible to use a support made by impregnating plastic or paper with binder resin together with conductive particles such as carbon black, tin oxide particles, titanium oxide particles, silver particles, or a conductive plastic support. it can. In addition, examples of the shape of the support include a cylindrical shape and a belt shape, and a cylindrical shape is preferable.

  Between the support and the photosensitive layer (charge generation layer, charge transport layer) or the undercoat layer (also referred to as an intermediate layer) described below, interference fringes are suppressed by scattering of laser light, etc. A conductive layer for coating may be provided.

  The conductive layer is obtained by applying a conductive layer coating solution obtained by dispersing conductive particles such as carbon black, metal particles, and metal oxide particles together with a binder resin and a solvent, and drying and drying the obtained coating film. It can be formed by curing.

  Examples of the binder resin used for the conductive layer include phenol resin, polyurethane, polyamide, polyimide, polyamideimide, polyamic acid, polyvinyl acetal, epoxy resin, acrylic resin, melamine resin, and polyester.

  Examples of the solvent used in the conductive layer coating solution include organic solvents such as alcohols, sulfoxides, ketones, ethers, esters, aliphatic halogenated hydrocarbons, halogenated aromatic compounds, and aromatic compounds.

  The film thickness of the conductive layer is preferably 1 to 40 μm, and more preferably 2 to 20 μm.

  An undercoat layer having a barrier function or an adhesive function may be provided between the support or the conductive layer and the photosensitive layer (charge generation layer, charge transport layer). The undercoat 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 undercoat layer can be formed by applying an undercoat layer coating solution obtained by dissolving a resin (binder resin) in a solvent, and drying and / or curing the obtained coating film.

  Examples of the resin (binder resin) used for the undercoat layer include acrylic resin, allyl resin, alkyd resin, ethyl cellulose resin, ethylene-acrylic acid copolymer, epoxy resin, casein resin, silicone resin, gelatin resin, nylon, phenol Resins, butyral resins, polyacrylates, polyacetals, polyamideimides, polyamides, polyallyl ethers, polyimides, polyurethanes, polyesters, polyethylenes, polycarbonates, polystyrenes, polysulfones, polyvinyl alcohols, polybutadienes, polypropylenes, ureas, and the like. The undercoat layer can also be formed using a material such as aluminum oxide.

  Examples of the solvent used in the coating solution for the undercoat layer include alcohols, sulfoxides, ketones, ethers, esters, aliphatic halogenated hydrocarbons, and aromatic compounds.

  The thickness of the undercoat layer is preferably 0.05 to 7 μm, and more preferably 0.1 to 2 μm.

  Examples of the charge generating substance 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, quinacridone pigments, azurenium salt pigments, cyanine dyes, xanthene dyes, Examples include quinoneimine dyes, styryl dyes, and cadmium sulfide. These charge generation materials may be used alone or in combination of two or more.

  When the photosensitive layer is a laminated photosensitive layer, 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, and nylon. , Phenolic resin, butyral resin, benzal resin, polyacrylate, polyacetal, polyamideimide, polyamide, polyallyl ether, polyarylate, polyimide, polyurethane, polyester, polyethylene, polycarbonate, polystyrene, polysulfone, polyvinyl acetal, polybutadiene, polypropylene, methacrylic resin , Urea resin, vinyl chloride-vinyl acetate copolymer, vinyl acetate resin and the like. Among these, a butyral resin is preferable. These may be used alone or in combination as a mixture or copolymer.

  The charge generation layer may be formed by applying a charge generation layer coating solution obtained by dispersing a charge generation material together with a binder resin and a solvent, and drying and / or curing the obtained coating film. it can. Examples of the dispersion treatment 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: 0.5 to 1: 4 (mass ratio).

  Examples of the solvent used in the charge generation layer coating solution include organic solvents such as alcohols, sulfoxides, ketones, ethers, esters, aliphatic halogenated hydrocarbons, halogenated aromatic compounds, and aromatic compounds.

  The thickness of the charge generation layer is preferably 0.001 to 6 μm, and more preferably 0.01 to 2 μm.

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

  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.

  When the photosensitive layer is a laminated photosensitive layer, examples of the binder resin used for the charge transport layer include acrylic resin, acrylonitrile resin, allyl resin, alkyd resin, epoxy resin, silicone resin, nylon, phenol resin, and phenoxy resin. , Butyral resin, polyacrylamide, polyacetal, polyamideimide, polyamide, polyallyl ether, polyarylate, polyimide, polyurethane, polyester, polyethylene, polycarbonate, polystyrene, polystyrene, polysulfone, polyvinyl butyral, polyphenylene oxide, polybutadiene, polypropylene, methacrylic resin, Examples include urea resin, vinyl chloride resin, and vinyl acetate resin. Among these, polyarylate and polycarbonate are preferable. These may be used alone or in combination as a mixture or copolymer.

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

  Solvents used in the coating solution for the charge transport layer include ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as toluene and xylene, ethers such as 1,4-dioxane and tetrahydrofuran, Hydrocarbons substituted with halogen atoms such as chlorobenzene, chloroform and carbon tetrachloride are used.

  The thickness of the charge transport layer is preferably 5 to 30 μm, and more preferably 6 to 25 μm.

  In addition, an antioxidant, an ultraviolet absorber, a plasticizer, and the like can be added to the charge transport layer as necessary.

  When the photosensitive layer is a single-layer type photosensitive layer, the single-layer type photosensitive layer is for a single-layer type photosensitive layer obtained by dispersing the charge generating substance and the charge transporting substance together with the binder resin and the solvent. It can form by apply | coating a coating liquid and drying the obtained coating film.

  In addition, a protective layer for the purpose of protecting the photosensitive layer may be provided on the photosensitive layer. The protective layer can be formed by applying a protective layer coating solution obtained by dissolving the above-described various resins (binder resins) in a solvent, and drying and / or curing the obtained coating film. .

  The thickness of the protective layer is preferably 0.01 to 10 μm, and preferably 0.1 to 7 μm.

  When applying the coating solution for each layer, for example, a coating method such as a 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 can be used.

  FIG. 2 shows a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.

  In FIG. 2, reference numeral 11 denotes a cylindrical electrophotographic photosensitive member of the present invention, which is rotationally driven around a shaft 12 in the direction of an arrow at a predetermined peripheral speed. The surface (circumferential surface) of the electrophotographic photosensitive member 11 is charged to a positive or negative potential by the charging unit 13 during the rotation process. Next, the surface of the electrophotographic photoreceptor 11 is irradiated with image exposure light 14 from exposure means (not shown) such as slit exposure or laser beam scanning exposure. Thus, an electrostatic latent image corresponding to the target image information is formed on the surface of the electrophotographic photosensitive member 11.

  The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 11 is developed with the toner of the developing unit 15, and a toner image is formed on the surface of the electrophotographic photoreceptor 11. Next, the toner image formed on the surface of the electrophotographic photosensitive member 11 is transferred to the transfer material 17 such as paper by the transfer unit 16. The transfer material 17 is taken out from a paper feeding unit (not shown) in synchronization with the rotation of the electrophotographic photosensitive member 11 and fed between the electrophotographic photosensitive member 11 and the transfer means 16.

  The transfer material 17 onto which the toner image has been transferred is separated from the surface of the electrophotographic photosensitive member 11 and is introduced into the fixing unit 18 to be subjected to image fixing, whereby an image formed product (print, copy) is taken out of the electrophotographic apparatus. Printed out.

  After the toner image is transferred, the surface of the electrophotographic photosensitive member 11 is cleaned by removing the transfer residual toner by a cleaning unit 19 having a cleaning blade in contact with the surface of the electrophotographic photosensitive member 11. Then, after being subjected to charge removal processing by irradiation with pre-exposure light 20 from a pre-exposure means (not shown), it is repeatedly used for image formation. When the charging unit 13 is a contact charging unit using a charging roller or the like, pre-exposure is not always necessary.

  In the present invention, among the components selected from the electrophotographic photosensitive member 11, the charging unit 13, the developing unit 15, the cleaning unit 19, and the like, 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. 2, the charging means 13, the developing means 15 and the cleaning means 19 are integrally supported together with the electrophotographic photosensitive member 11 to form a cartridge, and the electrophotographic apparatus main body using the guide means 22 such as a rail of the electrophotographic apparatus main body. The process cartridge 21 is removable.

  The image exposure light 14 is, for example, reflected light or transmitted light from a document, or a document is read by a sensor, converted into a signal, laser beam scanning performed in accordance with this signal, LED array drive, or liquid crystal shutter array drive It is the light irradiated by etc.

  The electrophotographic photoreceptor of the present invention can be used not only for copying machines and laser beam printers but also for a wide range of electrophotographic applications such as CRT printers, LED printers, FAX, liquid crystal printers, and laser plate making.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.

Example 1
An aluminum cylinder having a diameter of 30 mm and a length of 260 mm was used as a support.

  Next, 50 parts of titanium oxide particles coated with tin oxide containing 10% by weight of antimony oxide, 25 parts of resol type phenol resin, 30 parts of methoxypropanol, 30 parts of methanol and silicone oil (polydimethylsiloxane polyoxyalkylene copolymer). A coating solution for a conductive layer was prepared by placing 0.002 part of a polymer, weight average molecular weight: 3000) in a sand mill using glass beads having a diameter of 1 mm, followed by dispersion treatment for 2 hours. This conductive layer coating solution was dip-coated on a support, and the resulting coating film was cured at 140 ° C. for 20 minutes to form a conductive layer having a thickness of 20 μm.

  Next, an undercoat layer coating solution was prepared by dissolving 5 parts of N-methoxymethylated 6 nylon in 95 parts of methanol. The undercoat layer coating solution was applied onto the conductive layer by dip coating, and the resulting coating film was dried at 100 ° C. for 20 minutes to form an undercoat layer having a thickness of 0.5 μm.

  Next, Bragg angles (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction of 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 ° and 10 parts of a crystalline form of hydroxygallium phthalocyanine crystal (charge generating substance) having a strong peak at 28.3 °, 0.1 part of a compound represented by the following structural formula (1),

5 parts of polyvinyl butyral (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 250 parts of cyclohexanone were placed in a sand mill using glass beads having a diameter of 1 mm and dispersed for 1 hour. By adding 250 parts, a charge generation layer coating solution was prepared. This charge generation layer coating solution was dip-coated on the undercoat layer, and the resulting coating film was dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.16 μm.

  Next, 40 parts of a compound (charge transport material) represented by the following structural formula (2),

5 parts of a compound (charge transport material) represented by the following structural formula (3),

And 50 parts of polyarylate having a structural unit represented by the following structural formula (4) (weight average molecular weight: 115000, molar ratio of terephthalic acid skeleton to isophthalic acid skeleton: terephthalic acid skeleton / isophthalic acid skeleton = 50/50)

Was dissolved in 300 parts of monochlorobenzene to prepare a coating solution for a charge transport layer. This charge transport layer coating solution was dip-coated on the charge generation layer, and the resulting coating film was dried at 120 ° C. for 1 hour to form a charge transport layer having a thickness of 25 μm.

  Next, perfluoroether oil (trade name: demnum, manufactured by Daikin Industries, Ltd.) is used as a fluorine base oil, and polytetrafluoroethylene particles (trade names: Teflon (registered trademark), manufactured by DuPont) are used as fluorine. Fluorine-based grease (trade name: demnum L200, manufactured by Daikin Industries, Ltd., NLGI consistency number: 2 (admixture consistency: 280)) as a system thickener was dispersed in hydrofluoroether at 1% by mass. . The obtained dispersion was dip coated on the surface of the charge transport layer and dried at 60 ° C. for 1 hour. Furthermore, a 10% by mass methanol dispersion of polymethylsilsesquioxane fine particles (trade name: Tospearl 120, manufactured by Momentive Co., Ltd.) having an average circularity of 1.0 and an average particle size of 2.0 μm as spherical inorganic fine particles. Further, it was applied by dip coating and dried.

  Thus, an electrophotographic photosensitive member was produced.

  The produced electrophotographic photosensitive member was mounted on the following evaluation apparatus, and an image was output. The presence / absence of the cleaning blade and the cleaning state (whether toner slipped out) were confirmed. This evaluation was performed in a high temperature and high humidity (32.5 ° C./85% RH) environment.

  In the evaluation, first, the produced electrophotographic photosensitive member is mounted on a process cartridge of a monochrome laser beam printer (product name: laser jet 4300n) manufactured by Hewlett Packard as an evaluation apparatus, and 2000 images are output, and 5 Blade deflection and cleaning state were evaluated at each stage after the first image output (initial stage) and after the 2000th image output (endurance). During the evaluation, the contact line pressure of the cleaning blade against the surface of the electrophotographic photosensitive member was set to be 30 g / cm. The charging means of the evaluation device is a contact charging device having a charging roller.

  The presence or absence of blade curling was confirmed visually, and evaluation was performed according to the following criteria.

initial:
A = No blade drooling,
B = Blade curl occurrence After durability:
AA = blade wrinkle does not occur even when 2000 images are output A = blade wrinkle occurs during output of 501 to 1000 images B = blade wrinkle occurs during output of 101 to 500 images C = 6 to 100 images Blade wobbling during output In the cleaning state, toner slipping was visually confirmed, and evaluation was performed according to the following criteria.

initial:
A = No toner slipping B = Toner slipping occurred After durability:
AA = No toner slipping out even when 2000 images are output A = Toner slipping out during output of 501-1000 images B = Toner slipping out during output of 101-500 images C = 6-100 images Toner slip occurs during output

(Example 2)
The same procedure as in Example 1 was performed except that polymethylsilsesquioxane fine particles (trade name: Tospearl 145, Momentive Co., Ltd.) having an average circularity of 1.0 and an average particle size of 4.5 μm were used as the spherical inorganic fine particles. Thus, an electrophotographic photosensitive member was produced.

(Example 3)
Electrophotographic photosensitivity in the same manner as in Example 1 except that silica fine particles having a mean circularity of 1.1 and a mean particle size of 0.5 μm (trade name: High Plessica, Ube Nitto Kasei Co., Ltd.) were used as spherical inorganic fine particles. The body was made.

Example 4
Electrophotographic photosensitivity in the same manner as in Example 1 except that silica fine particles having a mean circularity of 1.1 and an average particle size of 1.0 μm (trade name: High Plessica, Ube Nitto Kasei Co., Ltd.) were used as spherical inorganic fine particles. The body was made.

(Example 5)
In the same manner as in Example 1, except that a fluorine oil having a kinematic viscosity of 1,500 mm ² / s (trade name: Daifroyl # 20, 1000CS, Daikin Industries, Ltd.) was used instead of the fluorine composition. A photographic photoreceptor was prepared.

(Example 6)
Except that fluorine-based grease spray (trade name: Sumitec F5 spray, manufactured by Sumiko Lubricant Co., Ltd., NLGI consistency number: 2 (mixing consistency: 279)) was used as the fluorine-based composition. In the same manner as in Example 1, an electrophotographic photosensitive member was produced.

(Comparative Example 1)
Examples were used except that lithium-based grease (trade name: Albania grease S2, manufactured by Showa Shell Sekiyu KK, NLGI consistency number: 2 (mixed consistency: 273)) was used instead of the fluorine-based composition. In the same manner as in Example 1, an electrophotographic photosensitive member was produced.

(Comparative Example 2)
Example 1 except that urea-based grease (trade name: U-4, manufactured by Nippon Oil Co., Ltd., NLGI consistency number: 3 (mixing consistency: 255)) was used instead of the fluorine-based composition. In the same manner as above, an electrophotographic photosensitive member was produced.

(Comparative Example 3)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that silicone oil (trade names: KF-96, 1000CS, manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of the fluorine-based composition.

(Comparative Example 4)
An electrophotographic photoreceptor is produced in the same manner as in Example 1 except that crosslinked polystyrene particles having an average particle size of 2.0 μm (trade name: SX, manufactured by Soken Chemical Industry Co., Ltd.) are used instead of the spherical inorganic fine particles. did.

(Comparative Example 5)
Example 1 was used except that polymethylsilsesquioxane fine particles (trade name: Tospearl 240, manufactured by Momentive Co., Ltd.) having irregular shapes (average circularity of 2.1) were used instead of the spherical inorganic fine particles. Thus, an electrophotographic photosensitive member was produced.

(Comparative Example 6)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that spherical inorganic fine particles were not used in Example 1.

(Comparative Example 7)
In Example 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that no fluorine-based grease was used.

  Table 1 shows the evaluation results of the electrophotographic photoreceptors of Examples 1 to 6 and Comparative Examples 1 to 7.

101 Spherical inorganic fine particles 102 Fluorine grease 103 Electrophotographic photosensitive member

Claims (9)

(I) fluorinated oil, or fluorinated grease comprising a fluorinated base oil and a fluorinated thickener;
(Ii) spherical inorganic fine particles;
An electrophotographic photosensitive member, wherein the surface is coated with a fluorine-based composition containing   The electrophotographic photosensitive member according to claim 1, wherein the spherical inorganic fine particles have an average circularity of 1.0 to 2.0.   The electrophotographic photosensitive member according to claim 1, wherein the spherical inorganic fine particles have an average particle size of 0.1 to 5.0 μm.   The electrophotographic photosensitive member according to claim 1, wherein the fluorine-based composition contains the fluorine-based grease.   The electrophotographic photosensitive member according to claim 4, wherein the consistency of the fluorine-based grease is NLGI No. 1 to No. 3.   6. The electrophotographic photosensitive member according to claim 4, wherein the fluorine base oil contained in the fluorine grease is at least one selected from the group consisting of a fluorocarbon oil, a perfluoroether oil, and a perfluoroalkyl ether oil. .   The electrophotographic photosensitive member according to any one of claims 4 to 6, wherein the fluorinated thickener contained in the fluorinated grease is polytetrafluoroethylene.   An electrophotographic photosensitive member according to any one of claims 1 to 7, a charging means for charging the surface of the electrophotographic photosensitive member, and a cleaning blade in contact with the surface of the electrophotographic photosensitive member. A process cartridge, which integrally supports a cleaning means having a detachable attachment to an electrophotographic apparatus main body.   An electrophotographic photosensitive member according to any one of claims 1 to 7, charging means for charging the surface of the electrophotographic photosensitive member, and image exposure light is irradiated to the surface of the electrophotographic photosensitive member. Image exposing means for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member; developing means for developing the electrostatic latent image with toner to form a toner image on the surface of the electrophotographic photosensitive member; and the toner An electrophotographic apparatus comprising: transfer means for transferring an image from a surface of the electrophotographic photosensitive member to a transfer material; and cleaning means having a cleaning blade in contact with the surface of the electrophotographic photosensitive member.