JP2009025627A - Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus - Google Patents

Abstract

An electrophotographic photosensitive member, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus are provided that reduce image disturbance and the like in a transfer portion caused by a rapid change in paper speed at a fixing portion.
SOLUTION: On the outermost surface of the electrophotographic photosensitive member, 10 independent concave portions are formed at a density of 10 or more per 100 μm square, and the major axis of the concave portion and the circumferential direction of the surface are formed. When the angle formed is θ, the concave portion is formed so that 85 ° <θ ≦ 90 °, the average depth of the concave portion is Rdv-A, and the average minor axis diameter is Lpc. -A, when the average major axis diameter is Rpc-A, the Rdv-A is 0.5 μm or more and 4.0 μm or less, the Lpc-A is 0.5 μm ≦ Lpc-A ≦ 4.0 μm, and the Rpc− An electrophotographic photoreceptor, wherein A is in the range of not less than twice the average minor axis diameter Lpc-A and not more than 50 μm.
[Selection] Figure 1

Description

  The present invention relates to an electrophotographic photosensitive member, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus. More specifically, the present invention relates to an electrophotographic photosensitive member having a concavo-convex shape on the surface, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus.

  At present, a photosensitive layer (organic photosensitive layer) using an organic material as a photoconductive substance (a charge generating substance or a charge transporting substance) is provided on a support as an electrophotographic photosensitive member due to advantages such as low cost and high productivity. An electrophotographic photosensitive member provided, so-called organic electrophotographic photosensitive member, has become widespread. The organic electrophotographic photoreceptor includes a charge generation layer containing a charge generation material such as a photoconductive dye or a photoconductive pigment, and a charge containing a charge transport material such as a photoconductive polymer or a photoconductive low molecular weight compound. The mainstream is a photosensitive layer formed by laminating a transport layer, that is, a so-called laminated photosensitive layer. This has advantages such as high sensitivity and various material designs.

  In general, an electrophotographic photoreceptor is used in a series of electrophotographic image forming processes including charging, exposure, development, transfer, cleaning, and the like together with a developer, and an electric external force or a mechanical external force is directly applied during use. It is done. Therefore, many problems occur due to these external forces, particularly in the surface layer. Specific examples include a decrease in durability performance due to the occurrence of scratches and wear, fusing and filming of a developer, a decrease in transfer efficiency, and image defects due to poor cleaning.

  The problems described above are becoming more difficult to solve due to the recent rapid progress of electrophotographic processes, colorization, tandemization, and miniaturization of electrophotographic apparatuses. In particular, in miniaturization, the paper conveying member from transfer to fixing is often omitted, and the distance between the transfer nip and the fixing nip is the smallest paper size that can be conveyed in the vertical direction of “postcard”. The size is 140 mm or less, which is slightly smaller than the size of 148 mm. In that case, when the leading edge of the paper enters the fixing nip, the trailing edge of the paper still remains in the transfer nip, that is, in the middle of the transfer process. Then, a rush shock (rapid speed change) to the fixing nip of the paper may affect the transfer process and disturb the image. In particular, the impact of the rush shock is increased with stiff paper such as cardboard.

For example, Patent Document 1 discloses a method for setting the frictional force due to the contact pressure at the nip portion of the transfer to be larger than the conveyance resistance of the transfer material received from the fixing roller pair. Further, Patent Document 2 discloses a method of absorbing the shock by forming a slight loop downward (curved deformation) on the paper with a V-shaped path. Patent Document 3 discloses a method of forming a loop by providing a drive control unit that performs drive control so as to temporarily decelerate the rotation of the pressure roller.
Japanese Patent Laid-Open No. 06-258773 JP 07-112843 A JP 2001-060023 A

  However, the prior art has the following problems. First, according to the method of Patent Document 1, if the contact pressure at the transfer nip is increased, the photoconductor is likely to be scratched / scratched. Further, in the method of Patent Document 2, it may be difficult to form a loop with stiff paper, and the shock may not be completely absorbed. Also in the method of Patent Document 3, it may be difficult to form a loop with stiff paper, and the shock may not be completely absorbed.

  The present invention has been made in view of the above problems, and provides an electrophotographic photosensitive member having high durability performance and suppressing the occurrence of image defects, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus. With the goal.

  The present inventors diligently studied the behavior of the contact portion between the paper used in the electrophotographic apparatus and the surface of the electrophotographic photosensitive member. As a result, it has been found that the above-mentioned problems can be effectively improved by providing predetermined fine concave portions on the surface of the electrophotographic photosensitive member, and the present invention has been made.

  The present invention is an electrophotographic photosensitive member comprising at least a support and a photosensitive layer provided on the support, and each of the outermost surfaces of the electrophotographic photosensitive member has an independent concave shape. When the angle between the major axis of the concave portion and the circumferential direction of the surface of the electrophotographic photosensitive member is θ, 85 ° <θ ≦ 90 The concave-shaped portion is formed on the outermost surface of the electrophotographic photosensitive member so as to be °, and the average depth of the concave-shaped portion (distance between the deepest portion of the concave-shaped portion and the aperture surface) Is Rdv-A, the average minor axis diameter is Lpc-A, and the average major axis diameter is Rpc-A, the Rdv-A is 0.5 μm to 4.0 μm, and the Lpc-A is 0.5 μm to 4 μm. 0.0 μm or less, and the Rpc-A is in the range of not less than twice the average minor axis diameter Lpc-A and not more than 50 μm. And wherein the door.

  In the present invention, the electrophotographic photosensitive member described above 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 the electrophotographic apparatus main body is supported. The process cartridge is detachable.

  Furthermore, the present invention is an electrophotographic apparatus comprising at least the electrophotographic photosensitive member described above, a charging unit, an exposure unit, a developing unit, and a transfer unit. Further, the shortest distance between the center of the contact nip of the transfer unit and the center of the fixing nip of the fixing device that fixes the toner by heat is 140 mm or less.

  According to the present invention, there are provided an electrophotographic photosensitive member that solves image disturbance in a transfer portion caused by a rapid change in paper speed at a fixing portion, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus. can do.

  Hereinafter, the electrophotographic photosensitive member of the present invention will be described in detail with reference to the drawings.

  First, the surface shape of the electrophotographic photosensitive member, which is a feature of the present invention, will be described.

  The electrophotographic photoreceptor of the present invention has a photosensitive layer on a conductive support, and each of the electrophotographic photoreceptors has an independent concave-shaped portion at a density of 10 or more per 100 μm square. Is formed. Then, on the outermost surface of the electrophotographic photoreceptor, when the angle formed by the major axis of the concave portion and the circumferential direction of the surface of the electrophotographic photoreceptor is θ, the angle θ is 85 ° <θ ≦ 90 °. The concave portion is formed so as to be. When the average depth indicating the distance between the deepest portion of the concave portion and the aperture surface is Rdv-A, the average minor axis diameter is Lpc-A, and the average major axis diameter is Rpc-A, they are It is in the range. That is, the Rdv-A is 0.5 μm or more and 4.0 μm or less, the Lpc-A is 0.5 or more and 4.0 μm or less, and the Rpc-A is twice or more the average short axis diameter Lpc-A and 50 μm or less. It is in the range.

  FIG. 1 shows an example of the surface of an electrophotographic photosensitive member having a concave portion having the characteristics of the present invention formed on the photosensitive layer, and a specific surface and cross-sectional shape of each concave portion. As shown in FIG. 1b, the surface shape of each concave-shaped portion includes various shapes such as a polygon such as an ellipse, a rectangle, and a hexagon, and a shape in which a curve is combined with part or all of the edges or sides of the polygon. Are possible. In addition, as shown in FIG. 1c, the cross-sectional shape thereof is one having edges such as a rectangle or a polygon, a corrugated shape made of a continuous curve, or a curve combined with a part or all of the edges of the rectangle or polygon. Various shapes such as those made possible are possible.

  Further, the plurality of formed concave portions may all have the same shape, size, depth, and angle, or may be a combination of these. For example, arrangements such as a to h shown in FIG. 2 are possible.

  Next, the average short axis diameter Lpc-A, the average long axis diameter Rpc-A, and the average depth Rdv-A will be described in detail. First, as shown in FIG. 1b, a short axis diameter Lpc in a concave shape formed by combining a curve with a part or all of an ellipse, a polygonal edge or a side, and each concave opening is projected in the horizontal direction. It is defined as the length of the minimum straight line among the straight lines obtained. For example, a short diameter is adopted for an ellipse, and a short side is adopted for a rectangle. Next, the major axis diameter Rpc is defined as the length of a straight line obtained by projecting each concave opening in the length direction of the minor axis diameter Lpc. For example, a long diameter is adopted for an ellipse, and a long side is adopted for a rectangle. As can be seen from the example of the rectangle, the major axis diameter Rpc in the present invention is the maximum straight line length (diagonal line in the case of a rectangle) among the straight lines obtained by projecting each concave opening in the horizontal direction. Does not necessarily match.

  When measuring the minor axis diameter Lpc, for example, as shown in FIG. 1c-3, when the boundary between the concave portion and the flat portion is not clear, the cross-sectional shape is taken into consideration and the smooth surface before roughening is used as a reference. A concave opening is defined, and the minor axis diameter Lpc is determined according to the above-mentioned definition. The average value of all the obtained short axis shapes is defined as the average short axis diameter Lpc-A. In measuring the major axis diameter Rpc, if the smooth surface before roughening is unclear as shown in FIG. 1c-6, a center line is provided in the cross-sectional view of adjacent recesses, and the major axis diameter is measured. Define Rpc. Then, statistical processing is performed on the major axis diameter Rpc of each of the obtained concave shapes per unit area, thereby defining an average major axis diameter Rpc-A that is an average value thereof. Finally, the depth Rdv is measured for all the concave portions in the measurement region. When the above-described virtual surface needs to be considered because the smooth surface before roughening is unclear, the distance between the virtual surface and the deepest portion of each concave shape portion is set to the depth Rdv of the concave shape portion. It is defined as And the average value of all the measured Rdv is defined as average depth Rdv-A.

  Here, in the present invention, the number of the concave portions is preferably 10 or more per 100 μm square, more preferably 20 or more. Furthermore, 20 or more and 30 or less is the most preferable range.

  The average minor axis diameter Lpc-A is preferably 0.5 μm or more and 4.0 μm or less, and the average major axis diameter Rpc-A is preferably not less than twice the average minor axis diameter Lpc-A and not more than 50 μm. . Moreover, it is preferable that average depth Rdv-A is 0.5 micrometer or more and 4.0 micrometers.

  When the average minor axis diameter Lpc-A is less than 0.5 μm, the paper fibers and the surface of the electrophotographic photosensitive member are not easily caught and the frictional force between the electrophotographic photosensitive member surface and the paper cannot be sufficiently obtained. It is difficult to obtain the effects of the present invention. On the other hand, if it is larger than 4.0 μm, the behavior of the cleaning blade is increased, and the cleaning is liable to occur.

  The same applies to the average depth Rdv-A of the concave-shaped portion. If the average depth is less than 0.5 μm, the paper and the concave-shaped portion are not easily caught, so that the friction force between the surface of the electrophotographic photosensitive member and the paper is sufficient. Therefore, the effect of the present invention cannot be obtained. On the other hand, if it is larger than 4.0 μm, the behavior of the cleaning blade is increased, and the cleaning is liable to occur.

  Further, since the end portion in the major axis radial direction of the concave shape is considered to be a starting point of catching between the paper and the concave portion on the surface of the electrophotographic photosensitive member, the average major axis diameter Rpc-A of the concave shape portion in the present invention is The thickness is less than 50 μm. Here, if the average major axis diameter Rpc-A is smaller than twice that of Lpc-A, the catching distance between the paper and the concave portion is reduced, and the effect is reduced. On the other hand, if the average major axis diameter Rpc-A is larger than 50 μm, the photosensitive member is likely to be scratched / scratched.

  In the present invention, the concave portion is formed with a density of 10 or more, more preferably 20 or more per 100 μm square. Thereby, it is guessed that the number of starting points increases and the effect of the present invention can be sufficiently obtained. When the number is less than 10 per 100 μm square, the number of starting points is too small, and the catch between the paper and the concave portion becomes weak, and the effect is hardly obtained. On the other hand, when the number per 100 μm square is more than 30, the area of the non-recessed portion becomes too small and the scratch / scratch of the photoconductor increases.

  In addition, an angle formed by the major axis of the concave portion and the circumferential direction of the surface of the electrophotographic photosensitive member is θ (see FIG. 3). As for the angle of the major axis, the perpendicular (90 °) with respect to the circumferential direction of the surface of the photoreceptor is the most effective, and it is considered that the frictional force decreases rapidly as the angle becomes smaller. It is assumed that there is a big limit. Therefore, the angle θ formed between the major axis and the circumferential direction of the photoreceptor surface is preferably in the range of 85 ° <θ ≦ 90 °.

  Next, a method for forming the surface shape of the electrophotographic photosensitive member of the present invention will be described.

  The method for forming the surface shape is not particularly limited as long as it satisfies the above-described requirements for the concave portion, and examples thereof include processing by excimer laser irradiation. Excimer laser is laser light emitted in the next step. First, a mixed gas of a rare gas such as Ar, Kr, or Xe and a halogen gas such as F or Cl is excited and coupled by applying energy by discharge, electron beam, X-ray, or the like. Thereafter, excimer laser light is emitted when dissociating by falling to the ground state. Examples of the gas used in the excimer laser include ArF, KrF, XeCl, and XeF, and any of them may be used, and KrF and ArF are particularly preferable.

As a method for forming the recess, a mask in which a laser beam blocking portion a and a laser beam transmitting portion b are appropriately arranged as shown in FIG. 4 is used. Only laser light that has passed through the mask is condensed by the lens and irradiated onto the workpiece, so that a recess having a desired shape and arrangement can be formed. At that time, since a large number of concave portions within a certain area can be simultaneously processed regardless of the shape and area of the concave portions, the process can be completed in a short time. Laser irradiation using a mask processes several mm ² to several cm ² per irradiation. In laser processing, as shown in FIG. 5, first, the workpiece is rotated by a workpiece rotating motor d. By rotating the laser irradiation position in the axial direction of the workpiece by the workpiece moving device e while rotating, the concave portions can be efficiently formed in the entire surface of the workpiece. The depth of the recess can be adjusted within the above range depending on the irradiation time and the number of times of irradiation with the laser beam. By doing so, it is possible to realize rough surface processing with high controllability of the size, shape and arrangement of the recesses, and with high accuracy and high flexibility. In addition, the electrophotographic photoreceptor according to the present invention may be subjected to the above-described processing using the same mask pattern, thereby increasing the roughness of the entire surface of the photoreceptor. FIG. 6 shows an example of the arrangement pattern of the concave portions.

  As another method for forming the surface shape of the electrophotographic photosensitive member of the present invention, a method of transferring a shape by pressing a mold having a predetermined shape against the surface of the electrophotographic photosensitive member is also possible. A method using a mold will now be described.

  FIG. 7 is a diagram showing an example of a schematic diagram of a pressure contact shape transfer processing apparatus using a mold in the present invention. After the predetermined mold B is attached to the pressure device A that can repeatedly press and release, the mold B is brought into contact with the photoconductor C at a predetermined pressure to transfer the shape. Thereafter, the pressurization is once released and the photosensitive member C is rotated, and then the pressurization and the shape transfer process are performed again. By repeating this process, it is possible to form a predetermined dimple shape over the entire circumference of the photoreceptor.

  For example, as shown in FIG. 8, first, a predetermined mold B having a length about the entire circumference of the photoreceptor C is attached to the pressure device A. Thereafter, a predetermined dimple shape can be formed over the entire circumference of the photoconductor by rotating and moving the photoconductor while applying a predetermined pressure to the photoconductor C.

  As another example, a sheet-shaped mold may be sandwiched between a roll-shaped pressurizing device and a photosensitive member, and surface processing may be performed while feeding the mold sheet.

  Note that the mold or the photoreceptor may be heated for the purpose of efficiently transferring the shape.

  The material, size, and shape of the mold itself can be selected as appropriate. Materials include metal and resin film with fine surface processing, silicon wafers and other surfaces patterned with resist, resin film with fine particles dispersed, and resin film with a predetermined fine surface shape. And the like. An example of the mold shape is shown in FIG. In addition, an elastic body can be installed between the mold and the pressure device for the purpose of imparting pressure uniformity to the photoconductor.

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

  As described above, the electrophotographic photosensitive member of the present invention includes a support and an organic photosensitive layer (hereinafter also simply referred to as “photosensitive layer”) provided on the support. In general, a cylindrical organic electrophotographic photosensitive member having a photosensitive layer formed on a cylindrical support is widely used, but a belt shape or a sheet shape is also possible.

  Even if the photosensitive layer is a single-layer type photosensitive layer containing the charge transport material and the charge generation material in the same layer, the charge generation layer containing the charge generation material and the charge transport layer containing the charge transport material Separated layered (functionally separated type) photosensitive layers may be used. The electrophotographic photoreceptor according to the present invention is preferably a multilayer photosensitive layer from the viewpoint of electrophotographic characteristics. In addition, even if the laminated type photosensitive layer is a normal type photosensitive layer in which the charge generation layer and the charge transport layer are laminated in this order from the support side, the reverse layer type photosensitive layer in which the charge transport layer and the charge generation layer are laminated in order from the support side. It may be a layer. In the electrophotographic photoreceptor according to the present invention, when a laminated photosensitive layer is employed, the charge generation layer may have a laminated structure, or the charge transport layer may have a laminated structure. Furthermore, a protective layer can be provided on the photosensitive layer for the purpose of improving durability.

  As a material for the support, any material that exhibits conductivity (conductive support) may be used. Examples thereof include metals (made of alloys) such as iron, copper, gold, silver, aluminum, zinc, titanium, lead, nickel, tin, antimony, indium, chromium, aluminum alloy, and stainless steel. 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. Also, 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, a plastic support having a conductive binder resin, etc. Can also be used.

  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.

  In addition, between the support and an intermediate layer or photosensitive layer (charge generation layer, charge transport layer), which will be described later, for the purpose of preventing interference fringes due to scattering of laser light and the like and covering the scratches on the support A conductive layer may be provided.

  The conductive layer may be formed using a conductive layer coating solution in which carbon black, a conductive pigment or a resistance adjusting pigment is dispersed and / or dissolved in a binder resin. You may add the compound which carries out hardening polymerization by heating or radiation irradiation to the coating liquid for conductive layers. The surface of the conductive layer in which the conductive pigment or the resistance adjusting pigment is dispersed tends to be roughened.

  The film thickness of the conductive layer is preferably 0.2 μm or more and 40 μm or less, more preferably 1 μm or more and 35 μm or less, and even more preferably 5 μm or more and 30 μm or less.

  Examples of the binder resin used for the conductive layer include polymers / copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic acid ester, methacrylic acid ester, vinylidene fluoride, and trifluoroethylene. . Moreover, polyvinyl alcohol, polyvinyl acetal, polycarbonate, polyester, polysulfone, polyphenylene oxide, polyurethane, cellulose resin, phenol resin, melamine resin, silicon resin, epoxy resin, and the like are also included.

  Examples of the conductive pigment and the resistance adjusting pigment include particles of metals (alloys) such as aluminum, zinc, copper, chromium, nickel, silver, and stainless steel, and those obtained by depositing these on the surface of plastic particles. . Alternatively, particles of metal oxide such as zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin-doped indium oxide, antimony or tantalum-doped tin oxide may be used. These may be used alone or in combination of two or more. When two or more types are used in combination, they may be simply mixed, or may be in the form of a solid solution or fusion.

  An intermediate 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 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.

  Examples of the material for the intermediate layer include polyvinyl alcohol, poly-N-vinylimidazole, polyethylene oxide, and ethyl cellulose. Moreover, ethylene-acrylic acid copolymer, casein, polyamide, N-methoxymethylated 6 nylon, copolymer nylon, glue, gelatin and the like can be mentioned. The intermediate layer can be formed by applying a coating solution for intermediate layer obtained by dissolving these materials in a solvent and drying it.

  The film thickness of the intermediate layer is preferably 0.05 μm or more and 7 μm or less, and more preferably 0.1 μm or more and 2 μm or less.

  Next, the photosensitive layer in the present invention will be described in more detail.

  Examples of the charge generating material used in the photosensitive layer in the present invention include selenium-tellurium, pyrylium, thiapyrylium dyes, various central metals, and various crystal systems (α, β, γ, ε, X type, etc.). A phthalocyanine pigment is mentioned. In addition, examples include anthanthrone pigments, dibenzpyrenequinone pigments, pyranthrone pigments, azo pigments such as monoazo, disazo, and trisazo, indigo pigments, quinacridone pigments, asymmetric quinocyanine pigments, and quinocyanine pigments. Furthermore, amorphous silicon may be used. These charge generation materials may be used alone or in combination of two or more.

  Examples of the charge transport material used in the electrophotographic photoreceptor of the present invention include a pyrene compound, an N-alkylcarbazole compound, a hydrazone compound, an N, N-dialkylaniline compound, a diphenylamine compound, a triphenylamine compound, and the like. Also included are triphenylmethane compounds, pyrazoline compounds, styryl compounds, stilbene compounds and the like.

  When functionally separating the photosensitive layer into a charge generation layer and a charge transport layer, the charge generation layer can be formed by the following method. That is, first, the charge generation material is dispersed together with a binder resin and a solvent in an amount of 0.3 to 4 times (mass ratio) using a homogenizer, ultrasonic dispersion, ball mill, vibration ball mill, sand mill, attritor or roll mill. . The charge generation layer coating solution obtained by dispersion is applied. By drying this, a charge generation layer can be formed. The charge generation layer may be a vapor generation film of a charge generation material.

  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 it. In addition, among the above charge transport materials, those having film formability alone can be formed as a charge transport layer by itself without using a binder resin.

  Examples of the binder resin used for the charge generation layer and the charge transport layer include polymers and copolymer of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic acid ester, methacrylic acid ester, vinylidene fluoride, and trifluoroethylene. Examples include coalescence. Moreover, polyvinyl alcohol, polyvinyl acetal, polycarbonate, polyester, polysulfone, polyphenylene oxide, polyurethane, cellulose resin, phenol resin, melamine resin, silicon resin, epoxy resin, and the like are also included.

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

  The thickness of the charge transport layer is preferably 5 μm or more and 50 μm or less, and more preferably 10 μm or more and 35 μm or less.

  As described above, the material design of the charge transport layer as the surface layer is important in the case of the above-described function-separated type photoreceptor in order to improve the durability, which is one of the characteristics required for the electrophotographic photoreceptor. . Examples include using high-strength binder resins, controlling the ratio between plastic charge transport materials and binder resins, and using polymer charge transport materials. In order to express it, it is effective to form the surface layer with a curable resin.

  In the present invention, the charge transport layer itself can be composed of a curable resin. Moreover, it is possible to form a curable resin layer as the second charge transport layer or protective layer on the above-described charge transport layer. The characteristics required for the curable resin layer are both the strength of the film and the charge transport capability, and it is generally composed of a charge transport material and a polymerized or crosslinkable monomer or oligomer.

  As the charge transport material, known hole transport compounds and electron transport compounds can be used. Examples of the polymerizable or crosslinkable monomer or oligomer include a chain polymerization material having an acryloyloxy group or a styrene group, and a sequential polymerization material having a hydroxyl group, an alkoxysilyl group, an isocyanate group, or the like. A combination of a hole transporting compound and a chain polymerization material is preferable from the viewpoint of the obtained electrophotographic characteristics, versatility, material design, manufacturing stability, etc., and further, both the hole transporting group and the acryloyloxy group are intramolecularly contained. Particularly preferred is a system for curing the compound contained in the above. As the curing means, known means such as heat, light and radiation can be used.

  In the case of the charge transport layer, the thickness of the cured layer is preferably 5 μm or more and 50 μm or less, more preferably 10 μm or more and 35 μm or less, as described above. In the case of the second charge transport layer or protective layer, the thickness is preferably 0.1 μm or more and 20 μm or less, and more preferably 1 μm or more and 10 μm or less.

  The electrophotographic photosensitive member having a surface layer produced by the above-described method can be subjected to the above-described laser processing or press-contact shape transfer processing using a mold to form a concave portion that characterizes the present invention. It is. As described above, the electrophotographic photosensitive member of the present invention is manufactured.

  Various additives can be added to each layer of the electrophotographic photosensitive member. Examples of additives include deterioration inhibitors such as antioxidants and ultraviolet absorbers, and lubricants such as fluorine atom-containing resin particles.

  Next, a process cartridge and an electrophotographic apparatus equipped with the electrophotographic photosensitive member of the present invention will be described.

  FIG. 10 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus provided with the electrophotographic photosensitive member of the present invention. In FIG. 10, an instruction number 1 is a cylindrical electrophotographic photosensitive member, and is driven to rotate around a shaft 2 in a direction indicated by an arrow at a predetermined peripheral speed. The peripheral surface of the electrophotographic photosensitive member 1 to be 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. Next, exposure light (image exposure light) 4 output from exposure means (not shown) such as slit exposure or laser beam scanning exposure is received. In this way, electrostatic latent images corresponding to the target image are sequentially formed on the peripheral surface of the electrophotographic photosensitive member 1. The charging means 3 is not limited to the contact charging means using a charging roller as shown in FIG. 10, but may be a corona charging means using a corona charger, or other types of charging means. May be.

  The electrostatic latent image formed on the peripheral surface of the electrophotographic photosensitive member 1 is developed with toner contained in the developer of the developing unit 5 to become a toner image. Next, the toner image formed and supported on the peripheral surface of the electrophotographic photosensitive member 1 is sequentially transferred onto a transfer material (such as paper) P by a transfer bias from a transfer unit (such as a transfer roller) 6. The transfer material P is fed from a transfer material supply means (not shown) between the electrophotographic photoreceptor 1 and the transfer means 6 (contact portion) in synchronization with the rotation of the electrophotographic photoreceptor 1. Also good. Further, instead of the transfer material, a system in which a toner image is once transferred to an intermediate transfer member or an intermediate transfer belt and then transferred to a transfer material (paper or the like) is also possible.

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

  The peripheral surface of the electrophotographic photosensitive member 1 after the transfer of the toner image is cleaned by receiving the transfer residual toner by a cleaning means (cleaning blade or the like) 7. Thereafter, after being subjected to static elimination treatment with pre-exposure light (not shown) from a pre-exposure means (not shown), it is repeatedly used for image formation. The transfer residual toner collected by the cleaning means 7 is sent to a waste toner container 9 as waste toner. The pre-exposure is not always necessary when the charging unit 3 is a contact charging unit using a charging roller as shown in FIG.

  The electrophotographic photosensitive member of the present invention is an electron having a shortest distance of 140 mm or less between the contact nip center of the transfer member that contacts the electrophotographic photosensitive member and the fixing nip center of the fixing device that fixes toner by heat. This is particularly effective for photographic devices.

  Further, the above-described electrophotographic photosensitive member 1 and at least one means selected from the group such as charging means 3, developing means 5, transfer means 6 and cleaning means 7 are housed in a container and integrally coupled as a process cartridge. May be configured. 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. FIG. 11 shows, as an example, a process cartridge in which the electrophotographic photosensitive member 1, the charging unit, and the cleaning unit are integrated.

  Examples of the present invention will now be described, but the present invention is not limited to the following examples. In the examples, “part” means “part by mass”.

(Example 1)
In this example, the electrophotographic photoreceptor of the present invention was produced.

  First, an aluminum sheet having a size of 150 × 150 mm and a thickness of 150 μm was used as a support. Next, the following components were dissolved in a mixed solvent of 450 parts of monochlorobenzene and 160 parts of methylal to prepare a surface layer coating material.

80 parts of the hole transporting compound of the following structural formula

100 parts of polycarbonate resin (Iupilon Z400, manufactured by Mitsubishi Engineering Plastics)

  Using this, the coating material for the surface layer was applied onto the support by the bar coating method, and was dried by heating in an oven at 90 ° C. for 40 minutes. As described above, a surface layer having a film thickness of 30 μm was formed on the aluminum sheet as the support.

<Formation of recess>
The aluminum sheet with a surface layer was rubbed at a pressure of 80 g / cm ² using water-resistant paper to form a large number of streak-like concave portions. The water-resistant paper is BOSS WATERPROF ABRASIVE PAPER ELECTROSTATIC COATED SILICON CARBIDE, model: P1000.

<Observation of formed recesses>
The surface shape of the sample obtained as described above was enlarged and observed with a laser microscope (manufactured by Keyence Corporation, VK-9500). As a result, as shown in FIG. 12, a large number of streak-shaped concave portions having a minor axis diameter Lpc of 0.5 to 4 μm, a depth Rdv of 0.5 to 4 μm, and an angle θ of 88 ° are formed. I found out.

<Measurement of friction coefficient>
The frictional force was measured under the following conditions using HEIDON SURFACE PROPERTY TESTER TYPE: 14 shown in FIG.

Load cell: 2000gf
Range: 10% FS
Filter: 10Hz
Polarity: OFF
Scan speed: 100 mm / min Scan distance: 20 mm
Sample size: 63mm x 63mm,
Weight: 200gf, 300gf, 500gf, 700gf

  The friction coefficient was calculated from the value of the frictional force obtained with each weight of 200 gf, 300 gf, 500 gf, and 700 gf and the value of the given weight. The friction coefficient can be obtained from the slope of an approximate straight line passing through 0 when the horizontal axis is weighted and the vertical axis is frictional force. The results are shown in Table 1 below.

(Comparative Example 1)
In this example, an aluminum sheet with a surface layer was produced in the same manner as in Example 1, but no recess was formed in the surface layer.

<Measurement of friction coefficient>
Measurements were performed in the same manner as in Example 1. The results are shown in Table 1 below.

  From Table 1, it can be seen that the coefficient of friction with respect to the paper varies greatly depending on the presence or absence of the recess. That is, by forming concave portions of appropriate sizes (width, depth, length) on the surface of the electrophotosensitive member at appropriate angles, the frictional force between the paper and the electrophotographic photosensitive member surface in the transfer portion increases. I understand that. Therefore, according to the present invention, even if there is a sudden change in the speed of the sheet when the leading edge of the sheet enters the fixing unit, the pressing pressure of the transfer member against the electrophotographic photosensitive member does not increase, and the transfer unit Less susceptible to that effect. Therefore, the image is less likely to be disturbed, and a good image quality can be obtained.

It is a figure which shows the example of the concave shape part of the electrophotographic photoreceptor surface of this invention. It is a schematic diagram of the various examples of the array pattern of a concave-shaped part. It is a figure which shows the definition of the angle of the major axis of the concave shape part of the electrophotographic photoreceptor surface of this invention. It is a figure which shows the example (partial enlarged view) of the arrangement pattern of a mask. It is a figure which shows the example of the schematic of a laser processing apparatus. It is a figure which shows the example (partial enlarged view) of the array pattern of a concave-shaped part. It is the schematic of the press-contact shape transfer processing apparatus by a mold. It is the schematic of another example of the press-contact shape transcription | transfer apparatus by a mold. It is a figure which shows the example of the shape of a mold. 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. FIG. 2 is a diagram illustrating an example of a schematic configuration of a process cartridge having the electrophotographic photosensitive member of the present invention. 3 is a schematic diagram of a concave portion obtained in Example 1. FIG. It is a schematic diagram of the apparatus used for the measurement of frictional force.

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 a Laser light blocking part b Laser light transmitting part c Excimer laser light irradiator d Work rotation motor e Work moving device f Photosensitive drum g Recessed portion non-forming portion h Recessed portion forming portion A Pressure device B Mold C Photosensitive member P Transfer material

Claims (4)

An electrophotographic photoreceptor comprising at least a support and a photosensitive layer provided on the support,
On the outermost surface of the electrophotographic photosensitive member, independent concave portions are formed at a density of 10 or more per 100 μm square, and the major axis of the concave portion and the outermost surface of the electrophotographic photosensitive member are formed. The concave portion is formed on the outermost surface of the electrophotographic photosensitive member so that 85 ° <θ ≦ 90 °, where θ is an angle with the circumferential direction, and
When the average depth of the concave portion (the distance between the deepest portion of the concave portion and the aperture surface) is Rdv-A, the average minor axis diameter is Lpc-A, and the average major axis diameter is Rpc-A, The Rdv-A is 0.5 μm or more and 4.0 μm or less, the Lpc-A is 0.5 μm ≦ Lpc-A ≦ 4.0 μm, and the Rpc-A is 2 times or more the average minor axis diameter Lpc-A to 50 μm. An electrophotographic photoreceptor having the following range.   The electrophotographic photosensitive member according to claim 1 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 attached to and detached from the electrophotographic apparatus main body. A process cartridge that is free to use.   An electrophotographic apparatus comprising at least the electrophotographic photosensitive member according to claim 1, a charging unit, an exposure unit, a developing unit, and a transfer unit.   4. The electrophotographic apparatus according to claim 3, wherein the shortest distance between the center of the contact nip of the transfer unit and the center of the fixing nip of the fixing device that fixes toner by heat is 140 mm or less.