Process cartridge

Abstract

To provide a process cartridge that achieves both low torque and cleanability.SOLUTION: A process cartridge comprises: a drum-shaped electrophotographic photoreceptor that has a support and a photosensitive layer; developing means for developing an electrostatic latent image on an outer surface of the electrophotographic photoreceptor by using toner; and a cleaning blade for removing the toner on the outer surface of the electrophotographic photoreceptor. The electrophotographic photoreceptor has wrinkles over the entire outer surface, and the fluid torque E of the toner is 320 mJ or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a process cartridge for use in an electrophotographic apparatus. [Background technology]

[0002] The electrophotographic photosensitive member used in an electrophotographic device is generally a drum-shaped electrophotographic photosensitive member (hereinafter also referred to as "electrophotographic photosensitive drum" or "photosensitive drum"). In an electrophotographic device, various electrical and mechanical external forces are applied to the surface of the electrophotographic photosensitive drum during repeated processes of charging, exposure, development, transfer, and cleaning. In particular, the frictional force generated between the electrophotographic photosensitive drum surface and the cleaning blade during cleaning is large, and affects image distortion due to wear of the electrophotographic photosensitive drum surface and a decrease in cleaning power.

[0003] In order to reduce wear on the surface of an electrophotographic photosensitive drum, improvements to the surface layer material have been made, and techniques for improving wear resistance by using a material with excellent wear resistance, such as a curable resin, for the surface layer have been studied.

[0004] Electrophotographic photosensitive drums are generally used in an electrophotographic image forming process that includes a charging step, an exposure step, a developing step, a transfer step, and a cleaning step. Among these steps, the cleaning step of removing residual toner on the electrophotographic photosensitive drum after the transfer step is an important step in obtaining a clear image. A common cleaning method is to press a rubber cleaning blade against the electrophotographic photosensitive drum and scrape off the toner.

[0005] On the other hand, in order to increase wear resistance, improvements have been made to reduce the contact area with the cleaning blade by forming irregularities on the surface of the electrophotographic photosensitive drum, thereby reducing frictional force. Reducing frictional force suppresses wear on the surface of the electrophotographic photosensitive drum and also reduces the contact torque with the cleaning blade. Patent Document 1 discloses an electrophotographic photosensitive drum having a specific groove shape on the surface of the electrophotographic photosensitive drum for the purpose of improving cleaning properties.

[0006] Patent Document 2 discloses a toner image carrier having a specific groove shape on the outer circumferential surface thereof, with the aim of achieving both high cleaning performance and suppressing cleaning blade wrap-in.

[0007] Patent Document 3 discloses that by performing a process to transfer the uneven shape of a mold member onto the surface of an electrophotographic photosensitive drum, an electrophotographic photosensitive drum having a surface with a highly stable uneven shape even in a high-temperature environment can be obtained. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-26240 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-250355 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-161786 Summary of the Invention [Problem to be solved by the invention]

[0009] In recent electrophotographic devices, there is a demand for even lower torque and for cleaning defects to be prevented. During the cleaning process, a deposit layer of small particles called a blocking layer, which is made up of toner additives, is formed on the cleaning blade and the surface of the electrophotographic photosensitive drum. Maintaining this blocking layer is important in cleaning. Cleaning defects refer to the phenomenon in which this blocking layer is destroyed for some reason, allowing toner and external additives to slip through the cleaning blade. When cleaning defects occur, streaks appear on the image. ConditionThis causes image defects, and even if they do not appear on the image, tiny amounts of toner and external additives that have slipped through can adhere to the charging roller on the drum surface, causing problems such as poor charging. Increasing the contact pressure of the cleaning blade can prevent toner from slipping through, but this increases the torque.

[0010] The technologies disclosed in Patent Documents 1 and 2 reduce torque by reducing the friction between the electrophotographic photosensitive drum and the cleaning blade, but because grooves are machined parallel to the process direction, toner and additives may slip through, resulting in poor cleaning.

[0011] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a process cartridge which achieves both low torque and improved cleaning performance. [Means for solving the problem]

[0012] The above object can be achieved by the present invention as follows: That is, the process cartridge according to the present invention comprises: a drum-shaped electrophotographic photosensitive member having a support and a photosensitive layer; developing means for developing an electrostatic latent image on the outer surface of the electrophotographic photosensitive member with a toner; toner contained in the developing means; and a cleaning blade for removing toner on the outer surface of the electrophotographic photosensitive member, wherein the electrophotographic photosensitive member has wrinkles over the entire outer surface, and the toner has a fluidity torque E of 320 mJ or more. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a process cartridge that achieves both low torque and good cleaning properties. [Brief explanation of the drawings]

[0014] [Figure 1]1A and 1B are diagrams showing an example of the uneven shape of wrinkles on an electrophotographic photosensitive drum, in which (A) is a top view of the outer surface of the electrophotographic photosensitive drum, and (B) is a graph showing height information obtained from surface observation of the outer surface of the electrophotographic photosensitive drum. [Figure 2] 1 is a diagram showing a schematic configuration of an electrophotographic apparatus having a process cartridge equipped with an electrophotographic photosensitive drum. [Figure 3] FIG. 2 is a diagram showing the appearance of a propeller-type blade of the powder fluidity analyzer. [Figure 4] FIG. 10 is a diagram showing a polishing machine used to polish the outer surface of an electrophotographic photosensitive drum in a comparative example. [Figure 5] FIG. 2 is a diagram showing an example of the uneven shape of wrinkles that the electrophotographic photosensitive drum according to the present invention has, and is a diagram showing the upper surface of the outer surface of the electrophotographic photosensitive drum. [Figure 6] 1A and 1B are diagrams showing an example of results obtained by numerically analyzing an electrophotographic photosensitive drum according to the present invention, in which (A) is a diagram showing a two-dimensional power spectrum F(r, θ) obtained by frequency analysis of wrinkles on the outer surface of an electrophotographic photosensitive drum, (B) is a diagram showing a one-dimensional radial distribution function obtained by integrating the two-dimensional power spectrum F(r, θ) in the θ direction, and (C) is a diagram showing the variation in power values ​​over the entire θ range when an angular distribution q(θ) is calculated from the two-dimensional power spectrum F(r, θ) for the frequency rp when the one-dimensional radial distribution function p(r) takes on a maximum value. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention will be described in detail below with reference to preferred embodiments. In the conventional technology of forming grooves on the surface, the direction of the grooves is parallel to the direction of rotation of the electrophotographic photosensitive drum. Therefore, it was found that, particularly when the contact pressure of the cleaning blade is low, the remaining toner on the electrophotographic photosensitive drum slips through the grooved portion and passes through the contact portion of the cleaning blade, causing streak-like image defects and contamination of the charging roller.

[0016] Therefore, as a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by configuring the process cartridge as follows. Specifically, the process cartridge according to the present invention comprises an electrophotographic photosensitive drum having a support and a photosensitive layer, a developing means for developing an outer surface of the electrophotographic photosensitive drum with a toner, and toner contained in the developing means; and a cleaning blade for removing toner on the outer surface of the electrophotographic photosensitive drum, wherein the electrophotographic photosensitive drum has wrinkles over the entire outer surface, and the toner has a fluidity torque E of 320 mJ or more.

[0017] Here, whether an electrophotographic photosensitive drum has mountain-like wrinkles over the entire outer surface can be confirmed, for example, as follows: In the present invention, the wrinkles refer to an uneven pattern in which a plurality of mountain-like convex surfaces are arranged at intervals. On the outer surface of the electrophotographic photosensitive drum, 76 observation areas are placed, each centered at the intersection of 19 line segments that divide the electrophotographic photosensitive drum into 20 equal parts in the axial direction and 4 line segments that divide the electrophotographic photosensitive drum into 4 equal parts in the circumferential direction. Each observation area is a square area with a side length of 50.0 μm, and each observation area is oriented so that one side of the square forming the observation area is parallel to the circumferential direction of the photosensitive drum. In this case, the following holds true for each of the 76 observation areas. A first reference line L1 passes through the center point of the observation area and is parallel to the circumferential direction of the electrophotographic photosensitive drum. Furthermore, 1799 reference lines obtained by rotating the first reference line L1 in 0.1° increments around the center point are designated L2 to L1799. Each of L1 to L1799 intersects with the convex portions of the wrinkles at multiple locations, and at least two selected from the multiple locations have different intersecting angles.

[0018] <Configuration of electrophotographic photosensitive drum> The electrophotographic photosensitive drum (drum-shaped electrophotographic photosensitive member) of the process cartridge according to the present invention is an electrophotographic photosensitive drum having a support and a photosensitive layer on the support, and is characterized in that the outer surface of the electrophotographic photosensitive drum has mountain-like wrinkles.

[0019] Fig. 1(A) is a top view showing an example of a square observation area with sides of 50.0 μm placed at an arbitrary position on the outer surface of an electrophotographic photosensitive drum. The mountain-like wrinkles in the present invention are stripe-like irregularities that can be observed when the surface of the electrophotographic photosensitive drum is viewed from above, as shown in Fig. 1(A). The stripe shapes are not distributed in a single direction, but are composed of curved portions, interrupted portions, branched portions, etc.

[0020] In addition, the ridge lines of the convex portions that form wrinkles in the present invention refer to straight lines or curves that connect the vertices of the convex portions of the striped uneven shape when the surface of the electrophotographic photosensitive drum is observed from above, as shown in 1a in Figure 1(A).

[0021] The method for identifying the convex portions and obtaining the ridge lines by top-view observation is not particularly limited. For example, height information measured using a confocal laser microscope can be analyzed by image analysis. Figure 1(B) shows an example of a cross-sectional profile of the uneven shape obtained from Figure 1(A). By identifying the vertex of the convex shape shown as 1b in Figure 1(B), the wrinkle ridge lines shown as 1a in Figure 1(A) can be obtained.

[0022] In the present invention, the ridgeline of a wrinkle has multiple curvatures within the ridgeline. Curvature is a quantity that represents the degree of curvature of a curve, and when the vicinity of an arbitrary point on the curve is approximated by a circle, the curvature χ is obtained as the reciprocal of the radius R of the circle, as shown in mathematical formula (I).

number

[0023] For example, at point 5b in Figure 5, the curvature is large because the wrinkle ridge 5a is curved more, and at point 5c in Figure 5, the curvature is small because the wrinkle ridge 5a is curved less.

[0024] The wrinkle ridgeline preferably has multiple inflection points within a square observation area with sides of 50.0 μm. An inflection point is a point where the direction of curvature of the curve changes, as shown in 5d in Figure 5, and the curvature at the inflection point is 0.

[0025] The detailed mechanism by which the present invention achieves its effects is presumed to be as follows. First, it is presumed that the wrinkles have a predetermined number of convex portions in a certain area, thereby reducing the contact area when the cleaning blade contacts the electrophotographic photosensitive drum and reducing frictional force. Furthermore, it is presumed that the ridges of the convex portions of the wrinkles are oriented in various directions, which also prevents toner from passing through the concave portions when the electrophotographic photosensitive drum rotates.

[0026] The electrophotographic photosensitive drum according to the present invention preferably satisfies the following conditions. That is, when wrinkle height information in the above observation region is frequency analyzed to obtain a two-dimensional power spectrum F(r,θ) with r as the frequency component and θ as the angle component, a one-dimensional radial distribution function p(r) obtained by integrating the two-dimensional power spectrum F(r,θ) in the θ direction has at least one maximum value, and when the angular distribution q(θ) is calculated from the two-dimensional power spectrum F(r,θ) for the frequency rp at which the one-dimensional radial distribution function p(r) takes on its maximum value, the variation in power values ​​over the entire θ range is 10% or less.

[0027] As a result of the inventors' investigations, it was found that the effects of the present invention can be highly obtained when the outer surface of the electrophotographic photosensitive drum has wrinkles and the uneven shape of the wrinkles has a predetermined periodicity, as shown in FIG.

[0028] The method for determining the periodicity of the wrinkle unevenness shape is not particularly limited, but an example thereof is a method in which height information is obtained from surface observation of the outer surface of an electrophotographic photosensitive drum, and then the obtained results are analyzed using a two-dimensional Fourier transform.

[0029] Specifically, when wrinkle height information is obtained using data number N1 × N2, the height at any point (n, m) in the plane is defined as h n,m Then, the two-dimensional power spectrum P(k,l) obtained by the discrete Fourier transform is given by the following equation (II).

number

[0030] where f k,l is given by the following formula (III):

number

[0031] Furthermore, the two-dimensional power spectrum P(k,l) obtained by formula (II) is transformed from the Cartesian coordinate system (k,l) to the polar coordinate system (r,θ) and expressed as the two-dimensional power spectrum F(r,θ), where r and θ satisfy the following formulas (IV) and (V), respectively.

number

number

[0032] In the present invention, in a square observation region with sides of 50.0 μm, height information obtained by measuring at regular intervals of 0.25 μm or less in two directions parallel to each side of the square is used for analysis.

[0033] 6A and 6B are diagrams showing an example of results obtained by numerically analyzing an electrophotographic photosensitive drum according to the present invention. Fig. 6A shows a two-dimensional power spectrum F(r,θ) obtained by frequency analysis of wrinkles on the outer surface of an electrophotographic photosensitive drum. Fig. 6B shows a one-dimensional radial distribution function obtained by integrating the obtained two-dimensional power spectrum F(r,θ) in the θ direction. Fig. 6C shows the variation in power values ​​over the entire θ range when the angular distribution q(θ) is calculated from the two-dimensional power spectrum F(r,θ) for the frequency rp at which the one-dimensional radial distribution function p(r) takes a maximum value.

[0034] 6(B), the electrophotographic photosensitive drum according to the present invention preferably has at least one maximum value in the radial distribution function p(r) obtained by linearizing the two-dimensional power spectrum F(r, θ) in the radial direction. This means that the wrinkles on the outer surface of the electrophotographic photosensitive drum are distributed at regular intervals.

[0035] 6(C), when the angular distribution q(θ) of F(rp,θ) is calculated for the frequency rp at which p(r) is maximized, it is preferable that the variation in power value over the entire θ range be within a certain range, specifically, 10% or less. This means that the periodicity of the uneven shape of the wrinkles on the outer surface of the electrophotographic photosensitive drum is uniformly distributed in any direction within the plane of the electrophotographic photosensitive drum.

[0036] When a square observation area with sides of 50.0 μm is placed at an arbitrary position on the outer surface of the electrophotographic photosensitive drum, and the angle θ is the angle between a tangent to the ridge line of the wrinkle-forming convex portion and a line parallel to the circumferential direction of the electrophotographic photosensitive drum, the observation area preferably includes one or more wrinkle ridge portions where θ is in the range of 45 degrees to 135 degrees. Here, in the example shown in FIG. 1(A), θ is, for example, the angle between a tangent line TL at point 1c on the ridge line of the wrinkle-forming convex portion and a line CL parallel to the circumferential direction of the electrophotographic photosensitive drum.

[0037] Furthermore, when observation points are placed at 5.0 μm intervals on the ridges of the convex portions that form wrinkles in the observation area, it is more preferable that the majority of the observation points in the observation area have θ within the range of 45 degrees to 135 degrees.

[0038] In the present invention, when a cross-sectional profile of the wrinkles is taken in the circumferential direction of the electrophotographic photosensitive drum, the cross-sectional profile is preferably gentle. Here, gentle means that the radius of curvature of the curve representing the cross-sectional profile of the wrinkles is 5 μm or more.

[0039] In the present invention, it is preferable that the irregular shape present on the surface of the electrophotographic photosensitive drum satisfies the following conditions. When the angle between the tangent of the ridge line of the convex portion that forms the wrinkles and a line parallel to the circumferential direction of the electrophotographic photosensitive drum is θ, the average value Lave of the distance between the ridge lines of adjacent convex portions that have ridge line portions where θ is in the range of 45 degrees to 135 degrees is 1.0 μm or more and 20.0 μm or less, and the average value Have of the height of the convex portions that have the above-mentioned ridge line portions is 0.5 μm or more and 3.0 μm or less.

[0040] Here, the average value Lave of the distances can be calculated as follows. Square observation areas, each 50.0 μm on a side, are placed at 76 specific locations on the outer surface of the electrophotographic photosensitive drum, and the following measurements are made for each observation area. First, five locations are arbitrarily selected from the ridges of wrinkle components within the observation area that have a tangent angle between 45 and 135 degrees. Next, measure the shortest distance from each of the five selected points to the edge of the adjacent wrinkle component (the closest of the two wrinkle components on either side) that has a tangent angle between 45 and 135 degrees. 76 The five measurements taken in each of the five observation areas were 76 ×5= 380 The arithmetic mean of the values ​​is calculated and the obtained value is called Lave.

[0041] If there is a wrinkle component that does not have a tangent angle between 45 and 135 degrees between two wrinkle components with a tangent angle between 45 and 135 degrees, the two wrinkle components with a tangent angle between 45 and 135 degrees are not adjacent and are excluded from the distance measurement. If any of the five arbitrarily selected points includes a point on such a wrinkle component, the point is reselected.

[0042] The average height value, have, can be determined by measuring the height at the same locations as those selected to calculate the average distance, Lave, and calculating the arithmetic mean of the measurements. When measuring the height, the height from the nearest valley bottom (two valley bottoms on both sides of the ridgeline) to the point on the ridgeline where the height is to be determined is measured, and the two values ​​obtained using the valley bottoms on both sides of the ridgeline as the reference are averaged.

[0043] <Toner composition> The toner is characterized by satisfying the following relational expression (1). 320(mJ)≦E (1) In the above formula (1), E represents the sum of the rotational torque and the vertical load obtained when a propeller blade in a powder fluidity analyzer is rotated at a peripheral speed of 10 mm / s at the outermost edge and inserted vertically into a toner powder layer in a container under a load of 3 kPa, measurement is started at a position 80 mm from the bottom of the powder layer, and the blade is inserted to a position 20 mm from the bottom. In other words, a larger value of E means a lower toner fluidity.

[0044] [Method for measuring E (mJ)] In the present invention, E (mJ) is measured using a "powder fluidity analyzer, powder rheometer FT4" (manufactured by Freeman Technology, hereinafter sometimes abbreviated as FT4).

[0045] Specifically, the measurement is carried out by the following procedure. In all operations, the propeller blade used is a 23.5 mm diameter blade 31 (material: SUS, hereinafter sometimes abbreviated as blade) made specifically for FT4, as shown in Figure 3. The measurement container used is a cylindrical split container made specifically for FT4 (model number: C4031, material: glass, diameter 25 mm, hereinafter sometimes abbreviated as container).

[0046] (1) Compression operation The toner powder layer is compressed by applying a pressure of 3 kPa. Specifically, a compression test piston (24 mm diameter, mesh-covered bottom) is installed in place of the propeller-type blade 31. 7.0 g of toner is placed in the container, and the piston is lowered at 0.1 mm / s to compress the toner. When the load on the piston reaches 3 kPa, the descent is stopped and the piston is held in this position for 60 seconds to form a compressed powder layer. This operation is repeated three times to form a compressed powder layer. Finally, the compressed powder layer is leveled off using the split part of the FT4 dedicated container mentioned above, and the toner on top of the compressed powder layer is removed.

[0047] (2) Measurement operation Propeller-type blade 31 is rotated counterclockwise relative to the powder bed surface (the direction in which the rotation of blade 31 pushes into the powder bed) so that the peripheral speed of the outermost edge of blade 31 is 10 mm / sec. Blade 31 is advanced vertically from the powder bed surface to a position 80 mm from the bottom of the toner powder layer at an advance speed that forms an angle of 5°. Blade 31 is then rotated counterclockwise relative to the powder bed surface so that the peripheral speed of the outermost edge of blade 31 is 10 mm / s, and advanced to a position 20 mm from the bottom of the powder bed at an advance speed that forms an angle of 5° with the vertical advance speed into the powder bed. Blade 31 is then moved further to a position 100 mm from the bottom of the powder bed at an advance speed of 2°, and removal is performed. Here, the angle related to the approach speed is the angle formed between the toner powder layer and the spiral path of the outermost edge of the propeller observed from the side when the blade is moved vertically while rotating. Once removal is complete, blade 31 is rotated alternately in small increments clockwise and counterclockwise to brush off the toner adhering to blade 31. E is the sum Et of the integral of the rotational torque over the travel distance and the integral of the vertical load over the travel distance obtained when blade 31 is advanced from a position 80 mm from the bottom of the toner powder layer to a position 20 mm from the bottom.

[0048] <Mechanism of effect> The inventors believe that the mechanism by which the process cartridge having the above configuration is effective in reducing torque and suppressing cleaning defects is as follows. It is presumed that the presence of the mountain-like wrinkles reduces the contact area when the cleaning blade comes into contact with the surface, thereby reducing frictional force. Condition The ridges of the wrinkles are oriented in various directions, so there is no problem with the image, such as streaks, which occur when toner is concentrated in one place and slips through the blade, as occurs with groove processing. However, when using low-fluidity toner, Condition The toner is subjected to various forces from the wrinkled slope, causing it to circulate just before the accumulation layer, causing tiny particles of toner and external additives to leak through the gaps in the blade. As a result, even if it does not cause image degradation, it still contaminates the charging device. Therefore, by combining a toner with low fluidity, it is possible to suppress the flow of toner just before the blocking layer, preventing the blocking layer from being destroyed and toner slippage, eliminating cleaning defects. Generally, using toner with low fluidity increases torque, but the wrinkled shape of the photosensitive drum surface makes it possible to suppress the increase in torque during the cleaning process, achieving a high level of both torque reduction and prevention of cleaning defects.

[0049] As shown by the above mechanism, the respective components of the photosensitive drum and the toner in the process cartridge according to one embodiment of the present disclosure exert a synergistic effect on each other, making it possible to achieve the effects according to the present disclosure. Hereinafter, the configuration of the electrophotographic photosensitive drum according to one aspect of the present disclosure will be described in detail.

[0050] [Electrophotographic photosensitive drum] The electrophotographic photosensitive drum has a support, a photosensitive layer provided on the support, and a surface layer containing a curable resin. A method for manufacturing an electrophotographic photosensitive drum includes preparing a coating liquid for each layer described below, coating the layers in the desired order, and drying the coating liquid. Examples of methods for applying the coating liquid include dip coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, and ring coating. Among these, dip coating is preferred from the viewpoints of efficiency and productivity. The support and each layer will be described below.

[0051] <Support> In the present invention, the electrophotographic photosensitive drum has a support. In the present invention, the support is preferably a conductive support having electrical conductivity. The shape of the support may be cylindrical, belt-like, sheet-like, or the like. Of these, a cylindrical support is preferred. The surface of the support may be subjected to electrochemical treatment such as anodization, blasting, cutting, or the like. The support is preferably made of a metal, a resin, or a glass. Examples of metals include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof, among which an aluminum support using aluminum is preferred. Furthermore, the resin or glass may be made conductive by mixing or coating it with a conductive material.

[0052] <Conductive layer> In the present invention, a conductive layer may be provided on the support. By providing the conductive layer, scratches and irregularities on the surface of the support can be concealed and light reflection on the surface of the support can be controlled. The conductive layer preferably contains conductive particles and a resin.

[0053] Examples of materials for the conductive particles include metal oxides, metals, and carbon black. Examples of metal oxides include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, bismuth oxide, etc. Examples of metals include aluminum, nickel, iron, nichrome, copper, zinc, silver, etc. Among these, it is preferable to use metal oxides as the conductive particles, and it is particularly preferable to use titanium oxide, tin oxide, or zinc oxide. When metal oxides are used as the conductive particles, the surface of the metal oxides may be treated with a silane coupling agent or the like, or the metal oxides may be doped with elements such as phosphorus or aluminum or oxides thereof. The conductive particles may have a layered structure including a core particle and a coating layer covering the core particle. Examples of the core particle include titanium oxide, barium sulfate, and zinc oxide. Examples of the coating layer include a metal oxide such as tin oxide. When metal oxide particles are used as the conductive particles, the volume average particle size is preferably 1 nm or more and 500 nm or less, and more preferably 3 nm or more and 400 nm or less.

[0054] Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, and alkyd resin. The conductive layer may further contain silicone oil, resin particles, a masking agent such as titanium oxide, and the like.

[0055] The average thickness of the conductive layer is preferably 1 μm or more and 50 μm or less, and particularly preferably 3 μm or more and 40 μm or less.

[0056] The conductive layer can be formed by preparing a coating solution for the conductive layer containing the above-mentioned materials and solvent, forming a coating film from this, and drying it. Examples of solvents used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Examples of dispersion methods for dispersing the conductive particles in the coating solution for the conductive layer include methods using a paint shaker, sand mill, ball mill, or liquid collision-type high-speed disperser.

[0057] <Undercoat layer> In the present invention, an undercoat layer may be provided on the support or the conductive layer. By providing an undercoat layer, the adhesion between layers can be improved and a charge injection blocking function can be imparted.

[0058] The undercoat layer preferably contains a resin. Alternatively, the undercoat layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinylphenol resin, alkyd resin, polyvinyl alcohol resin, polyethylene oxide resin, polypropylene oxide resin, polyamide resin, polyamic acid resin, polyimide resin, polyamideimide resin, and cellulose resin. Examples of the polymerizable functional group possessed by the monomer having a polymerizable functional group include an isocyanate group, a blocked isocyanate group, a methylol group, an alkylated methylol group, an epoxy group, a metal alkoxide group, a hydroxyl group, an amino group, a carboxyl group, a thiol group, a carboxylic anhydride group, and a carbon-carbon double bond group.

[0059] Furthermore, for the purpose of improving electrical properties, the undercoat layer may further contain an electron transporting substance, a metal oxide, a metal, a conductive polymer, etc. Among these, it is preferable to use an electron transporting substance or a metal oxide. Examples of the electron transport substance include a quinone compound, an imide compound, a benzimidazole compound, a cyclopentadienylidene compound, a fluorenone compound, a xanthone compound, a benzophenone compound, a cyanovinyl compound, an aryl halide compound, a silole compound, a boron-containing compound, etc. An electron transport substance having a polymerizable functional group may be used as the electron transport substance, and the undercoat layer may be formed as a cured film by copolymerizing the electron transport substance with the above-mentioned monomer having the polymerizable functional group. Examples of metal oxides include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, silicon dioxide, etc. Examples of metals include gold, silver, aluminum, etc. The undercoat layer may further contain additives.

[0060] The average thickness of the undercoat layer is preferably from 0.1 μm to 50 μm, more preferably from 0.2 μm to 40 μm, and particularly preferably from 0.3 μm to 30 μm.

[0061] The undercoat layer can be formed by preparing a coating solution for the undercoat layer containing the above-mentioned materials and solvent, forming a coating film from the coating solution, and drying and / or curing the coating film. Examples of the solvent used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0062] <Photosensitive layer> The photosensitive layer of an electrophotographic photosensitive drum is mainly classified into (1) a multi-layer type photosensitive layer and (2) a single-layer type photosensitive layer. (1) The multi-layer type photosensitive layer has a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. (2) The single-layer type photosensitive layer has a photosensitive layer containing both a charge generation material and a charge transport material.

[0063] (1) Laminated photosensitive layer The laminated photosensitive layer has a charge generating layer and a charge transport layer.

[0064] (1-1) Charge generation layer The charge generating layer preferably contains a charge generating material and a resin.

[0065] Examples of charge-generating materials include azo pigments, perylene pigments, polycyclic quinone pigments, indigo pigments, and phthalocyanine pigments. Among these, azo pigments and phthalocyanine pigments are preferred. Among phthalocyanine pigments, oxytitanium phthalocyanine pigments, chlorogallium phthalocyanine pigments, and hydroxygallium phthalocyanine pigments are preferred. The content of the charge generating material in the charge generating layer is preferably 40% by mass or more and 85% by mass or less, and more preferably 60% by mass or more and 80% by mass or less, based on the total mass of the charge generating layer.

[0066] Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, polyvinyl butyral resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinyl alcohol resin, cellulose resin, polystyrene resin, polyvinyl acetate resin, polyvinyl chloride resin, etc. Among these, polyvinyl butyral resin is more preferred.

[0067] The charge generating layer may further contain additives such as antioxidants and ultraviolet absorbers, etc. Specific examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, and benzophenone compounds.

[0068] The average thickness of the charge generating layer is preferably from 0.1 μm to 1 μm, and more preferably from 0.15 μm to 0.4 μm.

[0069] The charge generating layer can be formed by preparing a coating solution for the charge generating layer containing the above-mentioned materials and solvent, forming a coating film from the coating solution, and drying the coating solution. Examples of the solvent used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0070] (1-2) Charge transport layer The charge transport layer preferably contains a charge transport material and a resin. Examples of charge transport materials include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these materials. Among these, triarylamine compounds and benzidine compounds are preferred, and those having the following structures are preferably used. [ka] (In formula (1), R 1 ~R 10 each independently represents a hydrogen atom or a methyl group.

[0071] Examples of the structure represented by formula (1) are shown in formulas (1-1) to (1-10). Among these, the structures represented by formulas (1-1) to (1-6) are more preferred. [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka]

[0072] The resin used is a thermoplastic resin, such as polyester resin, polycarbonate resin, acrylic resin, or polystyrene resin. Among these, polycarbonate resin and polyester resin are preferred. As the polyester resin, polyarylate resin is particularly preferred.

[0073] The content of the charge transport material in the charge transport layer is preferably 25% by mass to 70% by mass, and more preferably 30% by mass to 55% by mass, based on the total mass of the charge transport layer.

[0074] The content ratio (mass ratio) of the charge transport material to the resin is preferably 4:10 to 20:10, and more preferably 5:10 to 12:10.

[0075] The charge transport layer may also contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slipping agents, and abrasion resistance improvers. Specific examples of such additives include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

[0076] The average thickness of the charge transport layer is preferably from 5 μm to 50 μm, more preferably from 8 μm to 40 μm, and particularly preferably from 10 μm to 30 μm.

[0077] The charge transport layer can be formed by preparing a coating solution for the charge transport layer containing the above-mentioned materials and solvent, forming a coating film from the coating solution, and drying the coating film. Examples of solvents used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Among these solvents, ether-based solvents and aromatic hydrocarbon-based solvents are preferred.

[0078] (2) Single-layer photosensitive layer The single-layer photosensitive layer can be formed by preparing a coating solution for the photosensitive layer containing a charge generating material, a charge transport material, a resin, and a solvent, forming the coating film, and drying the coating. The charge generating material, charge transport material, and resin are the same as those exemplified in "(1) Multilayer Photosensitive Layer" above.

[0079] <Protective layer> In the present invention, a protective layer may be provided on the photosensitive layer, which can improve durability. The protective layer preferably contains conductive particles and / or a charge transport material, and a resin.

[0080] Examples of conductive particles include particles of metal oxides such as titanium oxide, zinc oxide, tin oxide, and indium oxide.

[0081] Examples of the charge transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these materials. Among these, triarylamine compounds and benzidine compounds are preferred.

[0082] Examples of the resin include polyester resin, acrylic resin, phenoxy resin, polycarbonate resin, polystyrene resin, phenol resin, melamine resin, and epoxy resin. Among these, polycarbonate resin, polyester resin, and acrylic resin are preferred. The protective layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of the reaction include thermal polymerization, photopolymerization, and radiation polymerization. Examples of the polymerizable functional group possessed by the monomer having a polymerizable functional group include an acrylic group and a methacrylic group. A material having charge transport capability may be used as the monomer having a polymerizable functional group.

[0083] The compound having a polymerizable functional group may have a charge transport structure in addition to the chain polymerizable functional group. As the charge transport structure, a triarylamine structure is preferred in terms of charge transport. As the chain polymerizable functional group, an acryloyl group or a methacryloyl group is preferred. The number of functional groups may be one or more. Among these, it is particularly preferred to form a cured film containing a compound having multiple functional groups and a compound having one functional group, since distortion caused by polymerization between the multiple functional groups is easily eliminated.

[0084] Examples of the compound having one functional group are shown in (2-1) to (2-6). [ka] [ka] [ka] [ka] [ka] [ka]

[0085] Examples of the compound having multiple functional groups are shown in (3-1) to (3-7). [ka] [ka] [ka] [ka] [ka] [ka] [ka]

[0086] The protective layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slipping agents, and abrasion resistance improvers. Specific examples of such additives include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

[0087] The protective layer can be formed by preparing a coating solution for the protective layer containing the above-mentioned materials and solvent, forming a coating film from this, and drying and / or curing the coating film. Examples of the solvent used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, sulfoxide-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0088] <Method for forming irregularities on the surface of an electrophotographic photosensitive drum> Methods for forming irregularities on the surface of an electrophotographic photosensitive drum are classified into (1) a wrinkle formation method and (2) an embossed pattern formation method. (1) The wrinkle formation method is obtained by laminating films with different thermal expansion behaviors and then heating and cooling them, resulting in a pattern as shown in Figure 1(A). (2) The embossed pattern formation method, as disclosed in Patent Document 3, involves pressing a metal mold or the like against the surface of the photosensitive drum to form a pattern, and is widely known as a technique for imparting a surface shape to a photosensitive drum.

[0089] (1)Wrinkle shape The wrinkles are formed by forming a protective layer, which is a cross-linked cured film, on a charge transport layer whose main component is a thermoplastic resin, followed by a heat treatment. During this process, compressive stress is applied to the surface due to the difference in deformation between the protective layer and the charge transport layer, which is thought to cause the surface protective layer to buckle, resulting in the formation of wrinkles.

[0090] (2) Embossed shape The method for forming the embossed pattern includes a step of transferring the concave-convex shape of a mold member to the surface of the electrophotographic photosensitive member by pressing the mold member to contact the electrophotographic photosensitive member with the concave-convex shape. In this case, the concave-convex shape can be formed even on a photosensitive member without a protective layer, but it is preferable to have a protective layer from the viewpoint of durability.

[0091] FIG. 4 shows an example of a pressure contact shape transfer processing device for forming recesses on the surface of an electrophotographic photosensitive member. According to the pressure-contact shape transfer processing device shown in FIG. 4, while rotating the workpiece, that is, electrophotographic photosensitive member 2-1, a mold member 2-2 is continuously brought into contact with the surface (circumferential surface) of the workpiece, and pressure is applied, thereby forming recesses on the surface of the electrophotographic photosensitive member 2-1. Examples of materials for the pressure member 2-3 include metals, metal oxides, plastics, and glass. Among these, stainless steel (SUS) is preferred from the viewpoints of mechanical strength, dimensional accuracy, and durability. A mold member is installed on the upper surface of the pressure member 2-3. A support member (not shown) and a pressure system (not shown) installed on the lower surface allow the mold member 2-2 to contact the surface of the electrophotographic photosensitive member 2-1 supported by the support member 2-4 with a predetermined pressure. The support member 2-4 may be pressed against the pressure member 2-3 with a predetermined pressure, or the support member 2-4 and the pressure member 2-3 may be pressed against each other.

[0092] 4 is an example in which the surface of the electrophotographic photosensitive member 2-1 is continuously processed while the electrophotographic photosensitive member 2-1 is rotated or driven by the pressure member 2-3 being moved in a direction perpendicular to the axial direction of the electrophotographic photosensitive member 2-1. Furthermore, the surface of the electrophotographic photosensitive member 2-1 can also be continuously processed by fixing the pressure member 2-3 and moving the support member 2-4 in a direction perpendicular to the axial direction of the electrophotographic photosensitive member 2-1, or by moving both the support member 2-4 and the pressure member 2-3. From the viewpoint of efficient shape transfer, it is preferable to heat the mold member 2-2 and the electrophotographic photosensitive member 2-1.

[0093] Examples of mold member 2-2 include metal or resin films with fine surface processing, silicon wafers or the like with resist patterning on their surfaces, resin films with dispersed fine particles, and resin films with fine surface shapes that have been metal coated. In order to make the pressure applied to the electrophotographic photosensitive member 2-1 uniform, it is preferable to provide an elastic body between the mold member 2-2 and the pressure member 2-3.

[0094] The configuration of the toner according to one embodiment of the present disclosure will be described in detail below. [toner] The method for producing the toner particles of the present invention is not particularly limited as long as it can achieve the above-mentioned fluidity torque, and known production methods can be used. Among known production methods, the toner particles of the present invention are preferably suspension polymerization toners in which a radical polymerizable monomer and a colorant are dispersed, and then the resulting droplets are dispersed in an aqueous medium or the like to form toner particles having a desired particle size, followed by suspension polymerization to prepare toner particles. This is because particles having a sharp particle size distribution, high sphericity, and a substantially uniform surface material can be formed, and therefore stable fluidity and excellent charging characteristics can be easily obtained.

[0095] The method for producing the toner particles used in the present invention will be described below by taking as an example the suspension polymerization method which is most suitable for obtaining the toner particles. A polymerizable monomer, a colorant, a polar resin, a release agent, and other additives as required are uniformly dissolved or dispersed using a dispersing machine such as a homogenizer, a ball mill, a colloid mill, or an ultrasonic dispersing machine, and a polymerization initiator is then dissolved therein to prepare a polymerizable monomer composition.

[0096] Next, the polymerizable monomer composition is dispersed in an aqueous medium containing a dispersion stabilizer, and granulated to form particles, and the polymerizable monomer in the particles is polymerized to produce toner particles. The polymerization initiator may be added simultaneously with the addition of other additives to the polymerizable monomer, or may be mixed immediately before dispersing the polymerizable monomer composition in an aqueous medium. Also, immediately after granulation and before the start of the polymerization reaction, a polymerization initiator dissolved in a polymerizable monomer or a solvent can be added.

[0097] In the present invention, it is preferable to add a suitable acid for adjusting the pH during dispersion, granulation, and before the start of the polymerization reaction. As the acid used in the toner of the present invention, commonly used acids such as hydrochloric acid, sulfuric acid, and nitric acid can be used. By adjusting the pH of the aqueous solution during polymerization to an appropriate level, it is possible to obtain a toner having more uniform charging properties.

[0098] When a polar resin is added during the polymerization reaction from the dispersion step of the polymerizable monomer composition to the polymerization step, the state of existence of the polar resin can be controlled depending on the balance of polarity exhibited by the polymerizable monomer composition that becomes the toner particles and the aqueous dispersion medium. That is, by adding a polar resin, it becomes possible to separate functions according to the resin layer. Furthermore, the toner particles obtained by the suspension polymerization method are preferable because they have a core-shell structure in which the release agent component is encapsulated. Examples of polar resins include polyester resins, epoxy resins, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, and styrene-maleic acid copolymers.

[0099] Examples of polymerizable monomers constituting the binder resin used in the toner of the present invention include commonly used styrene-acrylic copolymers, styrene-methacrylic copolymers, epoxy resins, and styrene-butadiene copolymers. The polymerizable monomer constituting the binder resin may be a vinyl polymerizable monomer capable of radical polymerization, and may be a monofunctional or polyfunctional polymerizable monomer. Examples of polymerizable monomers for constituting the binder resin include the following: styrene; styrene-based monomers such as o-(m-, p-)methylstyrene and m-(p-)ethylstyrene; methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, octyl acrylate, octyl methacrylate, dodecyl acrylate, dodecyl methacrylate, stearyl acrylate, stearyl methacrylate, behenyl acrylate, behenyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, and diethyl acrylate. Lua acrylic acid ester monomers or methacrylic acid ester monomers such as aminoethyl, diethylaminoethyl methacrylate; and ene monomers such as butadiene, isoprene, cyclohexene, acrylonitrile, methacrylonitrile, acrylic acid amide, and methacrylic acid amide.

[0100] In the present invention, a crosslinking agent may be used when synthesizing the binder resin in order to increase the mechanical strength of the toner particles and to control the molecular weight of the THF-soluble component of the toner. Examples of bifunctional crosslinking agents include the following: divinylbenzene, bis(4-acryloxypolyethoxyphenyl)propane, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol #200, #400, and #600 diacrylates, dipropylene glycol diacrylate, polypropylene glycol diacrylate, polyester diacrylate (MANDA Nippon Kayaku), and the above diacrylates replaced with dimethacrylates. Examples of polyfunctional crosslinking agents include pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylate and its methacrylate, 2,2-bis(4-methacryloxypolyethoxyphenyl)propane, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, and triallyl trimellitate.

[0101] The release agent used in the present invention may be petroleum waxes such as paraffin wax, microcrystalline wax, petrolatum, and derivatives thereof; montan wax and derivatives thereof; hydrocarbon waxes produced by the Fischer-Tropsch process and derivatives thereof; polyolefin waxes such as polyethylene wax and polypropylene wax and derivatives thereof; natural waxes such as carnauba wax and candelilla wax and derivatives thereof; higher aliphatic alcohols; fatty acids such as stearic acid and palmitic acid; acid amide waxes; ester waxes; hydrogenated castor oil and derivatives thereof; vegetable waxes; animal waxes, etc. Of these, paraffin wax, ester wax, and hydrocarbon wax are particularly preferred from the viewpoint of excellent release properties.

[0102] Examples of polymerization initiators that can be used in the toner of the present invention include: azo or diazo polymerization initiators such as 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, and azobisisobutyronitrile; and peroxide polymerization initiators such as benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, and tert-butyl peroxypivalate. The type of polymerization initiator varies slightly depending on the polymerization method, but may be used alone or in combination, taking into account the 10-hour half-life temperature.

[0103] The toner of the present invention contains a colorant as an essential component to impart coloring power. Colorants preferably used in the present invention include the following organic pigments, organic dyes, and inorganic pigments.

[0104] Examples of organic pigments or organic dyes as cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds. Specific examples include: CI Pigment Blue 1, CI Pigment Blue 7, CI Pigment Blue 15, CI Pigment Blue 15:1, CI Pigment Blue 15:2, CI Pigment Blue 15:3, CI Pigment Blue 15:4, CI Pigment Blue 60, CI Pigment Blue 62, and CI Pigment Blue.

[0105] Examples of organic pigments or organic dyes as magenta colorants include the following: condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specific examples include the following: CI Pigment Red 2, CI Pigment Red 3, CI Pigment Red 5, CI Pigment Red 6, CI Pigment Red 7, CI Pigment Violet 19, CI Pigment Red 23, CI Pigment Red 48:2, CI Pigment Red 48:3, CI Pigment Red 48:4, CI Pigment Red 57:1, CI Pigment Red 81:1, CI Pigment Red 122, CI Pigment Red 144, CI Pigment Red 146, CI Pigment Red 150, CI Pigment Red 166, CI Pigment Red 169, CI Pigment Red 177, CI Pigment Red 184, CI Pigment Red 185, CI Pigment Red 202, CI Pigment Red 206, CI Pigment Red 220, CI Pigment Red 221, and CI Pigment Red 254.

[0106] Examples of organic pigments or organic dyes as yellow colorants include compounds typified by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specific examples include the following: CI Pigment Yellow 12, CI Pigment Yellow 13, CI Pigment Yellow 14, CI Pigment Yellow 15, CI Pigment Yellow 17, CI Pigment Yellow 62, CI Pigment Yellow 74, CI Pigment Yellow 83, CI Pigment Yellow 93, CI Pigment Yellow 94, CI Pigment Yellow 95, CI Pigment Yellow 97, CI Pigment Yellow 109, CI Pigment Yellow 110, CI Pigment Yellow 111, and CI Pigment Yellow 12. 0, CI Pigment Yellow 127, CI Pigment Yellow 128, CI Pigment Yellow 129, CI Pigment Yellow 147, CI Pigment Yellow 151, CI Pigment Yellow 154, CI Pigment Yellow 155, CI Pigment Yellow 168, CI Pigment Yellow 174, CI Pigment Yellow 175, CI Pigment Yellow 176, CI Pigment Yellow 180, CI Pigment Yellow 181, CI Pigment Yellow 191, CI Pigment Yellow 194.

[0107] Examples of black colorants include carbon black and those toned to black using the above-mentioned yellow colorant / magenta colorant / cyan colorant.

[0108] These colorants can be used alone or in a mixture, or in the form of a solid solution. The colorant used in the toner of the present invention is selected in consideration of hue angle, saturation, brightness, light resistance, OHP transparency, and dispersibility in the toner.

[0109] In the present invention, when toner particles are obtained by a polymerization method, it is necessary to pay attention to the polymerization inhibitory properties and migration properties into the aqueous phase of the colorant, and it is preferable to subject the colorant to a hydrophobic treatment using a substance that does not inhibit polymerization.

[0110] As the dispersion stabilizer used in preparing the aqueous medium, known inorganic and organic dispersion stabilizers can be used. Specific examples of inorganic dispersion stabilizers include the following: tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, magnesium carbonate, calcium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, and alumina.

[0111] Examples of organic dispersants include polyvinyl alcohol, gelatin, methyl cellulose, methylhydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, and starch.

[0112] Commercially available nonionic, anionic, and cationic surfactants can also be used, including the following: sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, and calcium oleate.

[0113] The dispersion stabilizer used in preparing the aqueous medium for the toner of the present invention is preferably an inorganic dispersion stabilizer having poor water solubility, and more preferably a poorly water soluble inorganic dispersion stabilizer that is soluble in acid.

[0114] In the present invention, when preparing an aqueous medium in which the above-mentioned dispersion stabilizer is dispersed, a commercially available dispersion stabilizer may be used as it is for dispersion. In order to obtain dispersion stabilizer particles having a fine, uniform particle size, an aqueous medium may be prepared by generating the dispersion stabilizer in a liquid medium such as water under high speed stirring. For example, when tricalcium phosphate is used as a dispersion stabilizer, a preferred dispersion stabilizer can be obtained by mixing an aqueous solution of sodium phosphate and an aqueous solution of calcium chloride under high speed stirring to form fine particles of tricalcium phosphate.

[0115] In the toner of the present invention, a charge control agent can be mixed with the toner particles as needed. By blending a charge control agent, it is possible to improve and stabilize the charge characteristics and to control the amount of triboelectric charge optimally according to the development system. Any known charge control agent can be used, and a charge control agent that can charge quickly and stably maintain a constant charge amount is particularly preferred.

[0116] Furthermore, when toner particles are produced by a direct polymerization method, a charge control agent that has low polymerization inhibition properties and produces a small amount of solubilized matter in an aqueous medium is particularly preferred. Examples of charge control agents that control toner to be negatively charged include: organic metal compounds and chelate compounds, as well as monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, oxycarboxylic acid and dicarboxylic acid-based metal compounds. Other examples include aromatic oxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenols. Further examples include urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, calixarene, and resin-based charge control agents. Among these, the polymer having a sulfonic acid functional group as the charge control agent is preferably a polymer or copolymer having a sulfonic acid group, a sulfonate salt group or a sulfonate ester group.

[0117] In the present invention, the value of E can be controlled by changing the type, amount, and conditions of addition of inorganic fine particles added to the toner particles.

[0118] [Process cartridges, electrophotographic devices] The process cartridge according to the present invention is characterized in that it integrally supports the electrophotographic photosensitive drum 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, and is detachably mountable to the main body of the electrophotographic apparatus.

[0119] The electrophotographic apparatus according to the present invention is characterized by comprising the electrophotographic photosensitive drum, charging means, exposure means, developing means and transfer means described above.

[0120] FIG. 2 shows an example of a schematic configuration of an electrophotographic apparatus having a process cartridge equipped with an electrophotographic photosensitive drum. Reference numeral 1 denotes a cylindrical electrophotographic photosensitive drum, which is driven to rotate around axis 2 in the direction of the arrow at a predetermined peripheral speed. The surface of electrophotographic photosensitive drum 1 is charged to a predetermined positive or negative potential by charging means 3. While the figure shows a roller charging method using a roller-type charging member, other charging methods, such as corona charging, proximity charging, and injection charging, may also be used. Exposure light 4 is irradiated onto the charged surface of electrophotographic photosensitive drum 1 from exposure means (not shown), forming an electrostatic latent image corresponding to the desired image information. The electrostatic latent image formed on the surface of electrophotographic photosensitive drum 1 is developed with toner contained in developing means 5, forming a toner image on the surface of electrophotographic photosensitive drum 1. The toner image formed on the surface of electrophotographic photosensitive drum 1 is transferred to transfer material 7 by transfer means 6. The transfer material 7 to which the toner image has been transferred is transported to fixing means 8, where the toner image is fixed and printed out from the electrophotographic device. The electrophotographic device may also have cleaning means 9 for removing toner and other deposits remaining on the surface of electrophotographic photosensitive drum 1 after transfer. Furthermore, a so-called cleanerless system may be used in which the deposits are removed by the developing unit 5 or the like without providing a separate cleaning unit 9. The electrophotographic apparatus may have a charge-removing mechanism that performs a charge-removing process on the surface of the electrophotographic photosensitive drum 1 with pre-exposure light 10 from pre-exposure unit (not shown). Furthermore, guide unit 12 such as a rail may be provided in order to mount and remove the process cartridge 11 according to the present invention to and from the main body of the electrophotographic apparatus.

[0121] The electrophotographic photosensitive drum can be used in laser beam printers, LED printers, copiers, and the like. [Example]

[0122] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited to the following examples without departing from the gist of the present invention. In the following examples, "parts" are by mass unless otherwise specified.

[0123] <Manufacturing of electrophotographic photosensitive drums> [Method for manufacturing photosensitive drum 1] An aluminum cylinder (JIS-A3003, aluminum alloy) having a diameter of 24 mm and a length of 257.5 mm was used as a support (conductive support).

[0124] [Conductive layer] Next, the following materials were prepared: 214 parts of titanium oxide (TiO2) particles (average primary particle diameter 230 nm) coated with oxygen-deficient tin oxide (SnO2) as metal oxide particles 132 parts of phenolic resin (phenolic resin monomer / oligomer) as a binder (product name: Plyofen J-325, manufactured by DIC Corporation, resin solid content: 60% by mass) 98 parts of 1-methoxy-2-propanol as solvent These were placed in a sand mill using 450 parts of 0.8 mm diameter glass beads and dispersed at 2000 rpm for 4.5 hours with a cooling water temperature of 18°C ​​to obtain a dispersion. The glass beads were removed from this dispersion using a mesh (mesh opening: 150 μm). Silicone resin particles (product name: Tospearl 120, manufactured by Momentive Performance Materials, Inc., average particle size: 2 μm) were added to the resulting dispersion as a surface roughening agent. The amount of silicone resin particles added was 10% by mass of the metal oxide particles and binder material in the dispersion after removing the glass beads. Silicone oil (product name: SH28PA, manufactured by Dow Corning Toray Co., Ltd.) was also added as a leveling agent to the dispersion at 0.01% by mass of the metal oxide particles and binder material in the dispersion. Next, a mixed solvent of methanol and 1-methoxy-2-propanol (mass ratio 1:1) was added to the dispersion so that the total mass of the metal oxide particles, binder material, and surface roughening agent in the dispersion (i.e., the mass of the solid content) was 67 mass% relative to the mass of the dispersion. The mixture was then stirred to prepare a conductive layer coating solution. This conductive layer coating solution was dip-coated onto a support and heated at 140°C for 1 hour to form a conductive layer with a thickness of 30 μm.

[0125] [Undercoat layer] Next, the following materials were prepared: ·4 parts of electron transport material (formula E-1) 5.5 parts blocked isocyanate (trade name: Duranate SBN-70D, manufactured by Asahi Kasei Chemicals Corporation) Polyvinyl butyral resin (S-LEC KS-5Z, manufactured by Sekisui Chemical Co., Ltd.) 0.3 parts 0.05 parts zinc(II) hexanoate (Mitsuwa Chemical Co., Ltd.) as a catalyst These were dissolved in a mixed solvent of 50 parts tetrahydrofuran and 50 parts 1-methoxy-2-propanol to prepare a coating solution for an undercoat layer, which was then dip-coated onto the conductive layer and heated at 170°C for 30 minutes to form an undercoat layer with a thickness of 0.7 µm. [ka]

[0126] [Charge generation layer] Next, 10 parts of crystalline hydroxygallium phthalocyanine, which exhibits peaks at 7.5° and 28.4° in a CuKα characteristic X-ray diffraction chart, and 5 parts of polyvinyl butyral resin (product name: S-LEC BX-1, manufactured by Sekisui Chemical Co., Ltd.) were prepared. These were added to 200 parts of cyclohexanone and dispersed for 6 hours using a sand mill equipped with 0.9 mm diameter glass beads. This was further diluted with 150 parts of cyclohexanone and 350 parts of ethyl acetate to obtain a charge generation layer coating solution. The resulting coating solution was dip-coated onto the undercoat layer and dried at 95°C for 10 minutes to form a charge generation layer with a thickness of 0.20 μm.

[0127] The X-ray diffraction measurements were carried out under the following conditions. [Powder X-ray diffraction measurement] Measuring equipment used: Rigaku Electric Co., Ltd., X-ray diffraction equipment RINT-TTRII X-ray tube:Cu Tube voltage: 50KV Tube current: 300mA Scanning method: 2θ / θ scan Scan speed: 4.0° / min Sampling interval: 0.02° Starting angle (2θ): 5.0° Stop angle (2θ): 40.0° Attachment: Standard sample holder Filter: Not used Incident Monochrome:Use Counter monochromator: Not used Divergence slit: open Divergence vertical limit slit: 10.00 mm Scattering slit: open Receiving slit: open Flat plate monochromator: used Counter: Scintillation counter

[0128] [Charge transport layer] Next, the following materials were prepared: 5 parts of a charge transport material (hole transport material) represented by the above structural formula (1-1) 5 parts of a charge transport material (hole transport material) represented by the above structural formula (1-3) 10 parts polycarbonate (product name: Iupilon Z400, manufactured by Mitsubishi Engineering Plastics Corporation) 0.02 parts of polycarbonate resin having copolymer units of the following structural formula (C-4) and the following structural formula (C-5) (x / y=0.95 / 0.05: viscosity average molecular weight=20,000) These were dissolved in a mixed solvent of 60 parts toluene, 2.3 parts methyl benzoate, and 12.8 parts tetrahydrofuran to prepare a coating solution for the charge transport layer. The charge generation layer was dip-coated with this coating solution to form a coating film, which was then dried at 100°C for 20 minutes to form a charge transport layer with a thickness of 16 μm. [ka] [ka]

[0129] [Protective layer] Next, the following materials were prepared: 8 parts of the compound represented by the above structural formula (2-1) 16 parts of the compound represented by the above structural formula (3-1) 0.1 parts of siloxane-modified acrylic compound (Simac US270, manufactured by Toagosei Co., Ltd.) These were mixed with 58 parts of cyclohexane and 25 parts of 1-propanol and stirred to prepare a coating liquid for the protective layer. This protective layer coating solution was dip-coated onto the charge transport layer to form a coating film, which was then dried at 40°C for 5 minutes. The coating film was then irradiated with an electron beam for 1.6 seconds under a nitrogen atmosphere while rotating the support (irradiated object) at a speed of 300 rpm under conditions of an acceleration voltage of 70 kV and a beam current of 5.0 mA. The dose at the outermost surface layer was 15 kGy. The first heating step was then performed under a nitrogen atmosphere, raising the temperature from 25°C to 100°C over 20 seconds to form a protective layer with a thickness of 1.5 μm. The oxygen concentration from electron beam irradiation to the subsequent heating step was 10 ppm or less. The coating film was then naturally cooled in the atmosphere to 25°C, and then subjected to a second heating step for 15 minutes under conditions where the coating film temperature reached 220°C, forming a wrinkled shape. In this manner, a cylindrical (drum-shaped) electrophotographic photosensitive drum having the protective layer of Example 1 was prepared.

[0130] [Method for manufacturing photosensitive drum 2] The photosensitive drum was manufactured in the same manner as the photosensitive drum 1, except that the thickness of the protective layer was set to 0.5 μm.

[0131] [Method for manufacturing the photosensitive drum 3] The photosensitive drum was manufactured in the same manner as the photosensitive drum 1, except that the thickness of the protective layer was set to 0.3 μm.

[0132] [Method for manufacturing photosensitive drum 4] The photosensitive drum was manufactured in the same manner as the photosensitive drum 1, except that after the charge transport layer was dried, it was rubbed with a nonwoven fabric in the circumferential direction and then a protective layer was applied. For the rubbing treatment, a Toraysee MK sheet (manufactured by Toray Industries, Inc.) was used as the nonwoven fabric for rubbing. The nonwoven fabric was stretched to prevent twisting, and the surface of the support, on which the charge transport layer had been formed, was pressed 3 mm from the position where it just came into contact with the surface. The support was rotated at 60 rpm for 1 second, and rubbing was performed in the circumferential direction.

[0133] [Method for manufacturing the photosensitive drum 5] The photosensitive drum was manufactured in the same manner as the photosensitive drum 4, except that the thickness of the protective layer was set to 0.5 μm.

[0134] [Method for manufacturing the photosensitive drum 6] The photosensitive drum was manufactured in the same manner as the photosensitive drum 4, except that the thickness of the protective layer was set to 0.3 μm.

[0135] [Method for manufacturing the photosensitive drum 7] The photosensitive drum was produced in the same manner as the photosensitive drum 1, except that after the charge transport layer was dried, it was rubbed with a nonwoven fabric in the longitudinal direction and then a protective layer was applied. For the rubbing treatment, a Toraysee MK sheet (manufactured by Toray Industries, Inc.) was used as the nonwoven fabric for rubbing. The nonwoven fabric was stretched to prevent twisting, and the surface of the support, on which the charge transport layer had been formed, was pressed in 3 mm from the position where it just came into contact, and rubbed in the longitudinal direction.

[0136] [Method for manufacturing the photosensitive drum 8] The photosensitive drum was manufactured in the same manner as the photosensitive drum 7, except that the thickness of the protective layer was set to 0.5 μm.

[0137] [Method for manufacturing the photosensitive drum 9] The photosensitive drum was manufactured in the same manner as the photosensitive drum 7, except that the thickness of the protective layer was set to 0.3 μm.

[0138] [Method for manufacturing the photosensitive drum 10] The photosensitive drum was manufactured in the same manner as the photosensitive drum 1, except that the second heating was not performed in the drying step after the protective layer was applied, and thus no wrinkles were formed.

[0139] [Method for manufacturing the photosensitive drum 11] A photosensitive drum was prepared without carrying out the second heating of the electrophotographic photosensitive drum of Example 1. The surface of this photosensitive drum was polished under the following conditions using the polishing machine shown in FIG. Polishing sheet feed speed: 400mm / min Photosensitive drum rotation speed: 240 rpm Abrasive grain: silicon carbide Average grain size of abrasive grains: 3 μm Polishing time: 20 seconds The polishing method involved feeding an abrasive sheet, which had a layer of abrasive grains dispersed in a binder resin on a sheet-like substrate, in the direction of the arrow while pressing the electrophotographic photosensitive drum against it for 20 seconds while rotating it in the direction of the arrow to perform a surface roughening treatment.

[0140] <Photosensitive drum evaluation> The photosensitive drums 1 to 5 were evaluated as follows. [Surface shape observation and analysis 1] For the outer surface of the electrophotographic photosensitive drum, the average value Lave of the distance between the ridges of adjacent convex portions having ridge portions with θ in the range of 45 degrees to 135 degrees and the average value have of the heights of the convex portions having ridge portions were determined by the method described above. The evaluation results are shown in Table 1.

[0141] [Surface shape observation and analysis 2] The surface shape of the outer surface of the electrophotographic photosensitive drum was observed under magnification using a laser microscope (VK-X200 manufactured by Keyence Corporation) to confirm whether the electrophotographic photosensitive drum had wrinkles over the entire outer surface. Furthermore, using the method described above, it was confirmed whether the observation area included one or more wrinkle ridges where θ was in the range of 45 to 135 degrees, and whether the observation points where θ was in the range of 45 to 135 degrees accounted for the majority of the observation points in the observation area. The following conditions 1, 2, and 3 were verified for all observation areas, and cases where all conditions were met were judged as A, cases where conditions 1 and 2 were met were judged as B, cases where only condition 1 was met were judged as C, and cases where none were met were judged as D. Condition 1: Has mountain range-like wrinkles. Condition 2: There is at least one tangent that satisfies 45°≦θ≦135°. Condition 3: The number of tangents that satisfy 45°≦θ≦135° is greater than the number of tangents that satisfy θ<45° and 135°<θ. The evaluation results are shown in Table 1.

[0142] [Table 1]

[0143] <Toner manufacturing example> The following describes examples of the production of toner used in the examples and comparative examples of the invention. First, a description will be given of a production example of the toner used in the examples and comparative examples of the present invention. The toner particles used in the examples and comparative examples of the present invention were produced by suspension polymerization, but the toner particles in the present invention are not necessarily limited to this, and toner particles obtained by pulverization, emulsion polymerization aggregation, or solution suspension methods can also be used.

[0144] [Example of Toner Particle Production] Toner particles 1 were produced by suspension polymerization as follows. The following materials were mixed and stirred for 2 hours to dissolve the polar resin, thereby obtaining a polar resin-containing monomer composition. Styrene 34.0 parts by mass n-Butyl acrylate 30.0 parts by mass Polar resin (saturated polyester resin [produced from terephthalic acid and PO-modified bisphenol A: Mp = 9000, Tg = 72°C, acid value = 12.0 mg KOH / g]) 5.0 parts by mass Charge control agent Bontron E-88 (manufactured by Orient Chemical Co., Ltd.) 1.0 parts by mass The following materials were mixed and stirred with zirconia beads (3 / 16 inch) in an attritor (manufactured by Mitsui Mining Co., Ltd.) at 200 rpm for 3 hours, and the beads were separated to obtain a colorant dispersion. Styrene 36.0 parts by mass Colorant: CI Pigment Blue 15:3 6.0 parts by weight

[0145] Next, Polar resin-containing monomer composition 70.0 parts by mass Colorant dispersion 42.0 parts by mass The above materials were mixed. The mixture was then heated to 60°C, and 10.0 parts by mass of wax (HNP-51, manufactured by Nippon Seiro Co., Ltd.) was added. Next, 5.0 parts by mass of a polymerization initiator, Perbutyl O (manufactured by NOF Corporation), was added, and the mixture was stirred for 5 minutes. Separately, 875 parts by weight of 0.1 mol / L Na3PO4 aqueous solution and 8.0 parts by weight of 10% hydrochloric acid were added to a container equipped with a high-speed agitator (Clearmix, M-Technique), the rotation speed was adjusted to 15,000 rpm, and the mixture was heated to 60°C. 70 parts by weight of 1.0 mol / L CaCl2 aqueous solution was added to the mixture to prepare an aqueous medium containing the fine, poorly water-soluble dispersant Ca3(PO4)2. Five minutes after adding the polymerization initiator to the polymerizable monomer composition, the 60°C polymerizable monomer composition was added to the aqueous medium heated to 60°C, and the mixture was granulated for 15 minutes while rotating the Clearmix at 15,000 rpm. The high-speed agitator was then replaced with a propeller-type agitator, and the mixture was refluxed at 60°C for 5 hours, after which the liquid temperature was increased to 80°C and the mixture was allowed to react for another 5 hours. After the polymerization was completed, the liquid temperature was lowered to about 20°C, and dilute hydrochloric acid was added to adjust the pH of the aqueous medium to 3.0 or less to dissolve the poorly water-soluble dispersant. After further washing and drying, toner particles with a weight average particle size (D4) of 5.96 μm were obtained.

[0146] [Production Example of Silica Microparticles 1] Stirred autoclave, BET specific surface area 300m 2 / g of dry silica (average primary particle size = 8 nm) was placed in the flask, and 20 parts of dimethyl silicone oil (kinematic viscosity 50 cSt) was added to 100 parts of the dry silica under a nitrogen atmosphere, followed by holding at 250°C for 30 minutes. After that, the mixture was taken out and subjected to a crushing treatment to obtain silica microparticles 1.

[0147] [Production Example of Silica Microparticles 2] A 3-liter glass reactor equipped with a stirrer, dropping funnel, and thermometer was charged with 687.9 g of methanol, 42.0 g of pure water, and 47.1 g of 28% by weight aqueous ammonia, and mixed. The resulting solution was adjusted to 35°C, and 1,100.0 g (7.23 mol) of tetramethoxysilane and 395.2 g of 5.4% by weight aqueous ammonia were simultaneously added with stirring. The tetramethoxysilane was added dropwise over 5 hours, and the aqueous ammonia over 4 hours. After the dropwise addition was completed, stirring was continued for an additional 0.2 hours to carry out hydrolysis, thereby obtaining a suspension of hydrophilic spherical sol-gel silica microparticles. The pH of the resulting suspension was then adjusted to approximately 3.5. After the adjustment, the reactor was heated to 75°C, and a solution of 8.8 g of octyltriethoxysilane dissolved in 220 ml of isopropyl alcohol was added dropwise to the reactor while stirring. After the addition, stirring was continued for 5 hours. After stirring, the mixture was cooled to room temperature and filtered. The residue was washed with ion-exchanged water and then heated and dried overnight at 120° C. Then, the mixture was pulverized using a pulverizer (manufactured by Hosokawa Micron Corporation) to obtain the desired silica microparticles 2.

[0148] <Toner 1 manufacturing example> Toner 1 was obtained by adding 0.15 parts by mass of silica fine particles 1 to 100.0 parts by mass of toner particles and mixing for 10 minutes at 4000 rpm using a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.). The flow torque E of Toner 1 was 346 mJ.

[0149] <Production example of toner 2 to toner 4> Toners 2 to 4 were obtained in the same manner as in the production example of Toner 1, except that the type and amount of silica fine particles added in the production example of Toner 1 were changed to those shown in Table 2. The values ​​of the fluidity torque E of the produced toners are also shown in Table 2.

[0150] [Table 2]

[0151] [Example 1] The electrophotographic device used was a modified Hewlett-Packard laser beam printer, product name HP Color LaserJet CP4525nd. It was configured to measure the drive current of the photosensitive drum rotation motor. It was also modified to allow adjustment and measurement of the voltage applied to the charging roller and the amount of image exposure light. In addition, the cyan cartridge was modified, the photosensitive drum was replaced with photosensitive drum 1, and the toner was refilled with toner 1. In addition, the contact pressure of the CRG cleaning blade against the electrophotographic photosensitive drum was changed to 40% of the product conditions.

[0152] [Examples 2 to 11, Comparative Examples 1 to 4] In Example 1, the process cartridges of Examples 2 to 11 and Comparative Examples 1 to 4 were prepared in the same manner as in Example 1, except that the photosensitive drum and toner were changed as shown in Table 4.

[0153] [evaluation] The process cartridges produced in Examples 1 to 11 and Comparative Examples 1 to 4 were used and evaluated under the following conditions.

[0154] [Relative torque evaluation] 100 sheets of A4 size plain paper were printed with a test chart with a printing ratio of 5%. The charging conditions were a dark potential of -500V, and the exposure conditions were an image exposure light amount of 0.25μJ / cm. 2 The drive current value (current value A) was read when 100 sheets were output. The larger the obtained current value, the greater the frictional force between the electrophotographic photosensitive drum and the cleaning blade. The measured value of the photosensitive drum 10 having no wrinkles on the surface and the process cartridge using the toner 3 was taken as current value B, and used as a control for the relative value. The ratio of the drive current value (current value A) to the drive current value (current value B) of the rotary motor of the electrophotographic photosensitive drum thus obtained was calculated. The obtained (current value A) / (current value B) values ​​were compared as relative torque values. A smaller relative value indicates a greater reduction in the friction force between the electrophotographic photosensitive drum and the cleaning blade. The evaluation results are shown in Table 3.

[0155] [Evaluation of image streaks] Furthermore, evaluation was carried out using halftone images immediately after printing 1000 sheets of horizontal line images with 10 spaces per line. Specifically, the number of slip-throughs (streaks) that were thought to be due to poor cleaning in the output images was visually counted and ranked. The evaluation results are shown in Table 3. Ranking of image streaks A: There are no streaks in the image quality and the image quality is good. B: Slight streaks occur. C: Lines appear in part of the image. D: Lines appear across the entire image

[0156] [Evaluation of charging roller contamination] The toner deposited on the C roller used in the evaluation of image streaks was taped, and the toner density was measured using a spectrodensitometer X-rite 504 (manufactured by X-rite), and the rank evaluation was performed based on the reflection density value. The larger the value, the greater the amount of toner adhering to the charging roller. Ranking of charging roller contamination A: Less than 0.1. B: 0.1 or more and less than 0.2. C: 0.2 or more and less than 0.3. D: 0.3 or more. The evaluation results are shown in Table 3.

[0157] [Table 3] [Explanation of symbols]

[0158] 1. Electrophotographic photosensitive drum 2-axis 3. Charging means 4 Exposure light 5. Developing method 6 Transfer Method 7 Transfer material 8 Fixing Method 9 Cleaning Method 10 Pre-exposure light 11 Process cartridge 12 Guidance means

Claims

1. a drum-shaped electrophotographic photoreceptor having a support and a photosensitive layer; a developing means for developing an electrostatic latent image on the outer surface of said electrophotographic photoreceptor with toner; toner contained in the developing means; a cleaning blade for removing toner from the outer surface of the electrophotographic photosensitive member, the electrophotographic photoreceptor has wrinkles over the entire outer surface, The process cartridge is characterized in that the toner has a fluidity torque E of 320 mJ or more.

2. A square observation area having a side length of 50.0 μm is placed at an arbitrary position on the outer surface of the electrophotographic photosensitive member, When the angle formed by the tangent of the ridge line of the convex portion forming the wrinkle and a line parallel to the circumferential direction of the electrophotographic photosensitive member is θ, 2. The process cartridge according to claim 1, wherein the observation area includes one or more ridge portions of the wrinkles where θ is within a range of 45 degrees to 135 degrees.

3. When observation points were placed at intervals of 5.0 μm on the ridges of the convex portions forming the wrinkles in the observation region, 3. The process cartridge according to claim 2, wherein the observation points within said observation region where said θ is in the range of 45 degrees to 135 degrees account for a majority of said observation points.

4. 4. The process cartridge according to claim 1, wherein when a cross-sectional profile of the wrinkles is taken in the circumferential direction of the electrophotographic photosensitive member, the cross-sectional profile is gentle.

5. When the angle formed by the tangent of the ridge line of the convex portion forming the wrinkle and a line parallel to the circumferential direction of the electrophotographic photosensitive member is θ, the average value Lave of the distances between the ridgelines of adjacent convex portions having ridgeline portions in which θ is in the range of 45 degrees to 135 degrees is 1.0 μm or more and 20.0 μm or less; 5. The process cartridge according to claim 1, wherein an average value "have" of heights of said convex portions having said ridge line portions is 0.5 μm or more and 3.0 μm or less.

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