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 used in an electrophotographic apparatus.

Background Art

[0002] An electrophotographic photoreceptor used in an electrophotographic apparatus is generally a drum-shaped electrophotographic photoreceptor (hereinafter also referred to as "electrophotographic photosensitive drum" or "photosensitive drum"). In an electrophotographic apparatus, various electrical external forces and mechanical external forces are applied to the surface of the electrophotographic photosensitive drum in the repeated processes of charging, exposure, development, transfer, and cleaning. Among them, the frictional force generated between the surface of the electrophotographic photosensitive drum and the cleaning blade during cleaning is large, which affects the wear of the surface of the electrophotographic photosensitive drum and the image disturbance due to the reduction of the cleaning force.

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

[0004] The electrophotographic photosensitive drum is generally used in an electrophotographic image forming process consisting of a charging process, an exposure process, a development process, a transfer process, and a cleaning process. Among them, the cleaning process for removing the residual toner on the electrophotographic photosensitive drum after the transfer process is an important process for obtaining a clear image. As this cleaning method, a method of pressing a rubber-like cleaning blade against the electrophotographic photosensitive drum and scraping off the toner is common.

[0005] On the other hand, in order to increase the wear resistance, improvements have also been made to reduce the contact area with the cleaning blade and the frictional force by forming irregularities on the surface of the electrophotographic photosensitive drum. When the frictional force is reduced, the wear of the surface of the electrophotographic photosensitive drum is suppressed, and the contact torque with the cleaning blade can also be lowered. Patent Document 1 discloses an electrophotographic photosensitive drum having a specific groove shape on its surface for the purpose of improving cleanability.

[0006] Patent Document 2 discloses a toner image carrier having a specific groove shape on the outer surface of the toner image carrier, with the aim of achieving both high cleaning performance and suppression of cleaning blade entanglement.

[0007] Patent Document 3 discloses that by applying a process to transfer the uneven shape of a mold member onto the surface of an electrophotographic photosensitive drum, an electrophotographic photosensitive drum can be obtained that has a surface with high stability of the uneven shape even in high-temperature environments. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2010-26240 [Patent Document 2] Japanese Patent Publication No. 2010-250355 [Patent Document 3] Japanese Patent Publication No. 2015-161786 [Overview of the project] [Problems that the invention aims to solve]

[0009] Recent electrophotographic devices require even lower torque and the prevention of cleaning failures. During the cleaning process, a layer of small particles called a blocking layer, composed of toner additives, is formed on the cleaning blade and the surface of the electrophotographic photosensitive drum. Maintaining this blocking layer is crucial for cleaning. A cleaning failure refers to the phenomenon where this blocking layer is destroyed for some reason, allowing toner and external additives to slip through the cleaning blade. When cleaning failures occur, streaky image defects appear in the image, and even if they do not appear in the image, the tiny toner and external additives that have slipped through can adhere to the charging roller on the drum surface, causing problems such as charging failures. Increasing the contact pressure of the cleaning blade can suppress toner slippage, but this increases torque.

[0010] In the technologies disclosed in Patent Documents 1 and 2, although torque reduction is achieved by reducing frictional force between the electrophotographic photosensitive drum and the cleaning blade, because grooves are machined parallel to the process direction, toner and additives can slip through, sometimes resulting in cleaning failures.

[0011] Therefore, the objective of the present invention is to provide a process cartridge that achieves both reduced torque and improved cleaning performance. [Means for solving the problem]

[0012] The above objective is achieved by the present invention as follows. That is, the process cartridge according to the present invention comprises a drum-shaped electrophotographic photoreceptor having a support and a photosensitive layer, developing means for developing an electrostatic latent image on the outer surface of the electrophotographic photoreceptor using toner, and a cleaning blade for removing toner from the outer surface of the electrophotographic photoreceptor, wherein the electrophotographic photoreceptor has wrinkles over its 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 cleaning performance.

Brief Description of the Drawings

[0014] [Figure 1] It is a diagram showing an example of the uneven shape of wrinkles of an electrophotographic photosensitive drum, (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 on the outer surface of the electrophotographic photosensitive drum. [Figure 2] It is a diagram showing a schematic configuration of an electrophotographic apparatus having a process cartridge equipped with an electrophotographic photosensitive drum. [Figure 3] It is a diagram showing the appearance of a propeller-type blade of a powder fluidity analyzer. [Figure 4] It is a diagram showing a polishing machine used for polishing the outer surface of an electrophotographic photosensitive drum in a comparative example. [Figure 5] It is a diagram showing an example of the uneven shape of wrinkles of an electrophotographic photosensitive drum according to the present invention, and is a diagram showing the top surface of the outer surface of the electrophotographic photosensitive drum. [Figure 6] It is a diagram showing an example of the result obtained by numerical analysis of the electrophotographic photosensitive drum according to the present invention. (A) is a diagram showing the two-dimensional power spectrum F(r,θ) obtained by frequency analysis of the wrinkles on the outer surface of the electrophotographic photosensitive drum, (B) is a diagram showing the 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 in 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.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, the present invention will be described in detail with reference to preferred embodiments. In the conventional technology where a groove shape is provided on the surface, since the direction of the groove shape was configured to be parallel to the rotation direction of the electrophotographic photosensitive drum, particularly when the contact pressure of the cleaning blade was low, it was found that residual toner on the electrophotographic photosensitive drum passed through the groove-shaped portion and slipped through the contact portion of the cleaning blade, resulting in streak-like image defects and contamination of the charging roller.

[0016] Therefore, as a result of intensive studies, the inventors of the present invention have found that the above problems can be solved by configuring the process cartridge as follows. Specifically, the process cartridge according to the present invention is a process cartridge including an electrophotographic photosensitive drum having a support and a photosensitive layer, developing means for developing on the outer surface of the electrophotographic photosensitive drum using toner, and a cleaning blade for removing the toner on the outer surface of the electrophotographic photosensitive drum, wherein the electrophotographic photosensitive drum has wrinkles over the entire outer surface, and the flowability torque E of the toner is 320 mJ or more.

[0017] Here, the fact that the electrophotographic photosensitive drum has mountain-range-like wrinkles over the entire outer surface can be confirmed, for example, as follows. The wrinkles in the present invention mean unevenness in which a plurality of mountain-range-like convex surfaces are arranged at intervals. On the outer surface of the electrophotographic photosensitive drum, observation regions are set with 76 intersection points of 19 line segments that divide the electrophotographic photosensitive drum into 20 equal parts in the axial direction and 4 line segments that divide it into 4 equal parts in the circumferential direction as the center points. Each observation region is a square region with a side length of 50.0 μm, and the orientation of each observation region is such that one side of the square forming the observation region is parallel to the circumferential direction of the photosensitive drum. At this time, the following holds for each of the 76 observation regions. Let L1 be a first reference line passing through the center point of the observation area and parallel to the circumferential direction of the electrophotographic photosensitive drum. Furthermore, let L2 to L1799 be the 1799 reference lines obtained by rotating the first reference line L1 at 0.1° intervals around the center point. In this case, each of L1 to L1799 intersects with the convex portions of the wrinkles at multiple points, and at least two of these points, selected from multiple points, have different intersection angles.

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

[0019] Figure 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 this invention are, as shown in Figure 1(A), stripe-like uneven shapes that can be observed when the surface of an electrophotographic photosensitive drum is viewed from above. These stripe shapes are not distributed in a single direction, but consist of curved portions, interrupted portions, branched portions, etc.

[0020] Furthermore, the ridges of the convex portions that form wrinkles in this invention refer to straight lines or curves formed by connecting the vertices of the convex portions of the stripe-like uneven shape when the surface of the electrophotographic photosensitive drum is observed from above, as shown in 1a of Figure 1(A).

[0021] There are no particular limitations on the method for identifying convex areas and obtaining ridge lines by observing the top surface, but for example, they can be identified by image analysis of height information measured using a confocal laser microscope. Figure 1(B) is an example of a cross-sectional profile of a convex shape obtained from Figure 1(A). By identifying the vertices of the convex shape shown in 1b of Figure 1(B), ridge lines of wrinkles like those shown in 1a of Figure 1(A) can be obtained.

[0022] Furthermore, in the present invention, the ridges of the wrinkles have multiple curvatures within those ridges. Curvature is a quantity that represents the degree of curvature of a curve, and the curvature χ is obtained as the reciprocal of the radius R of a circle when the vicinity of any point on the curve is approximated by a circle, as shown in equation (I).

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[0023] For example, at point 5b in Figure 5, the curvature is large because the curvature of the ridge 5a of the wrinkle is large, while at point 5c in Figure 5, the curvature is small because the curvature of the ridge 5a of the wrinkle is small.

[0024] Preferably, the ridges of the wrinkles have multiple inflection points within a square observation area with sides of 50.0 μm. An inflection point is a point where the curvature direction of the curve changes, as shown in 5d in Figure 5, and at the inflection point, the curvature 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, having a predetermined number or more protrusions within a certain range, reduce the contact area when the cleaning blade contacts the electrophotographic photosensitive drum, thereby reducing frictional force. Furthermore, it is presumed that because the ridges of the wrinkle protrusions face in various directions, the leakage of toner through the recesses is suppressed when the electrophotographic photosensitive drum rotates.

[0026] The electrophotographic photosensitive drum according to the present invention preferably satisfies the following conditions. In other words, when the wrinkle height information is frequency-analyzed in the above observation area and a two-dimensional power spectrum F(r,θ) is obtained with frequency component r and angular component θ, the 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 its maximum value, the variation in power values ​​over the entire θ range is 10% or less.

[0027] As a result of the inventors' investigation, it was found that the effects of the present invention can be obtained to a high degree when the outer surface of the electrophotographic photosensitive drum has wrinkles, and the uneven shape of these wrinkles has a predetermined periodicity, as shown in Figure 1.

[0028] There are no particular limitations on the method for determining the periodicity of the uneven shape of wrinkles, but one example is to obtain height information from surface observation of the outer surface of an electrophotographic photosensitive drum, and then analyze the obtained results using a two-dimensional Fourier transform.

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

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[0030] Here f k,l It is given by the following formula (III).

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[0031] Furthermore, the two-dimensional power spectrum P(k,l) obtained by equation (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). Here, r and θ satisfy the following equations (IV) and (V), respectively.

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

[0033] Figure 6 shows an example of the results obtained by numerical analysis of the electrophotographic photosensitive drum according to the present invention. Figure 6(A) shows the two-dimensional power spectrum F(r,θ) obtained by frequency analysis of wrinkles on the outer surface of the electrophotographic photosensitive drum. Figure 6(B) shows the one-dimensional radial distribution function obtained by integrating the obtained two-dimensional power spectrum F(r,θ) in the θ direction. Figure 6(C) 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 its maximum value.

[0034] As shown in Figure 6(B), it is preferable that the electrophotographic photosensitive drum according to the present invention has at least one maximum value in the radial distribution function p(r) obtained by converting the two-dimensional power spectrum F(r,θ) into one dimension in the radial direction. This means that the wrinkles and irregularities on the outer surface of the electrophotographic photosensitive drum are distributed at regular intervals.

[0035] Furthermore, as shown in Figure 6(C), when calculating the angular distribution q(θ) of F(rp,θ) for the frequency rp at which p(r) is maximum, it is preferable that the variation in power values ​​across the entire θ range is within a constant 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] It is preferable that the observation area includes one or more wrinkle ridges where θ is within the range of 45 to 135 degrees, when an observation area of ​​a square with sides of 50.0 μm is placed at any position on the outer surface of the electrophotographic photosensitive drum, and the angle between the tangent to the ridge of the protrusion that forms the wrinkle and a line parallel to the circumferential direction of the electrophotographic photosensitive drum is defined as θ. Here, θ is, for example, the angle between the tangent TL at point 1c on the ridge of the protrusion that forms the wrinkle and the line CL parallel to the circumferential direction of the electrophotographic photosensitive drum, as explained in the example shown in Figure 1(A).

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

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

[0039] Furthermore, in the present invention, it is preferable that the uneven surface of the electrophotographic photosensitive drum satisfies the following conditions. When θ is the angle between the tangent to the ridge of a convex portion that forms a wrinkle and a line parallel to the circumferential direction of the electrophotographic photosensitive drum, the average distance Lave between the ridges of adjacent convex portions having a ridge portion where θ is in the range of 45 to 135 degrees is 1.0 μm or more and 20.0 μm or less, and the average height have of the convex portion having the ridge portion is 0.5 μm or more and 3.0 μm or less.

[0040] Here, the average value Lave of the above distances can be calculated as follows. Square observation areas with sides of 50.0 μm are placed at 76 specific locations on the outer surface of the electrophotographic photosensitive drum, and the following measurements are performed for each observation area. First, select five arbitrary points from the ridges of wrinkle components within the observation area that have tangent angles between 45 and 135 degrees. Next, from each of the five selected points, measure the shortest distance to the edge of the adjacent wrinkle component (the closer of the two wrinkle components on either side) that has a tangent angle between 45 and 135 degrees. The arithmetic mean of the 75 values ​​obtained from 5 measurements in each of the 75 observation areas (75 × 5 = 375 values) is calculated, and this value is designated as Lave.

[0041] Furthermore, 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, those two wrinkle components with a tangent angle between 45 and 135 degrees are not considered adjacent and are excluded from the distance measurement. If any of the five arbitrarily selected locations contain points on such wrinkle components, the selection is changed.

[0042] Furthermore, the average height value 'have' can be determined by measuring the height at the same locations selected to determine the average distance value 'Lave', and then calculating the arithmetic mean of the obtained measurements. In measuring the height, the height from the point on the ridge for which the height is to be sought is measured from the nearest valley floor (two valley floors on either side of the ridge), and the two values ​​obtained using the valley floors on both sides of the ridge as a reference are averaged.

[0043] <Toner Configuration> The toner is characterized by satisfying the following relation (1). 320(mJ)≦E (1) In equation (1) above, E represents the sum of rotational torque and vertical load obtained when a powder flowability analyzer is inserted vertically into a toner powder layer in a container with a 3 kPa load applied, while the peripheral speed of the outermost edge of a propeller-type blade rotates at 10 mm / s. Measurement is started at a position 80 mm from the bottom of the powder layer, and the analyzer is inserted until it reaches a position 20 mm from the bottom. In other words, a larger value of E means that the toner's flowability is lower.

[0044] [Method for measuring E(mJ)] In this invention, E(mJ) is measured using a "Powder Rheometer FT4" (manufactured by Freeman Technology, hereinafter sometimes abbreviated as FT4).

[0045] Specifically, the measurement is performed using the following procedure. For all operations, the propeller-type blade used is the FT4-specific 23.5 mm diameter blade 31 (material: SUS, hereinafter sometimes abbreviated as "blade") shown in Figure 3. The measuring container is the FT4-specific cylindrical split container (model number: C4031, material: glass, diameter 25 mm, hereinafter sometimes abbreviated as "container") used.

[0046] (1) Compression operation The toner powder layer is compressed by applying a pressure of 3 kPa. Specifically, a compression test piston (24 mm in diameter, with a mesh at the bottom) is installed in place of the propeller-type blade 31 mentioned above. 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 held 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 section of the FT4-specific container mentioned above, removing the toner from the top of the compressed powder layer.

[0047] (2) Measurement procedure The propeller-type blade 31 is rotated counterclockwise relative to the surface of the powder layer (in the direction in which the powder layer is pushed in by the rotation of the blade 31) so that the peripheral speed of the outermost edge of the blade 31 is 10 mm / sec. The blade 31 is then inserted vertically from the surface of the powder layer to a position 80 mm from the bottom surface of the toner powder layer at an entry speed that forms an angle of 5°. Subsequently, the blade 31 is rotated counterclockwise relative to the surface of the powder layer so that the peripheral speed of the outermost edge of the blade 31 is 10 mm / sec, and is inserted to a position 20 mm from the bottom surface of the powder layer at an entry speed that forms an angle of 5° with the vertical entry speed into the powder layer. Furthermore, the blade 31 is moved to a position 100 mm from the bottom surface of the powder layer at a speed that forms an angle of 2°, and then removed. Here, the angle related to the entry speed is the angle between the helical trajectory of the outermost edge of the propeller, as observed from the side when the blade is rotated and moved vertically, and the toner powder layer. Once the extraction is complete, the blade 31 is rotated alternately in small clockwise and counterclockwise directions to brush off any toner adhering to it. Let E be the sum of the integral of the rotational torque with respect to the distance traveled and the integral of the vertical load with respect to the distance traveled when the blade 31 is inserted from a position 80 mm from the bottom surface of the toner powder layer to a position 20 mm from the bottom surface.

[0048] <Mechanism of action> The inventors believe that the mechanism by which the above-described process cartridge is effective in reducing torque and suppressing cleaning defects is as follows. It is presumed that the presence of mountain-like wrinkles reduces the contact area when the cleaning blade makes contact, thereby reducing friction. Because the ridges of the wrinkles on the mountain range face in various directions, image defects such as streaks caused by toner concentrating in one place and slipping past the blade, as can occur with groove processing, do not occur. However, when using low-flowability toner, the toner is subjected to various forces from the slopes of the wrinkles on the mountain range, causing it to move in a circulating manner before reaching the deposition layer, and minute amounts of toner and external additives leak out through the gaps in the blade. As a result, although it does not cause image defects, it contaminates the charged components. Therefore, by combining it with low-flowability toner, it is possible to suppress the flow of toner before reaching the block layer, preventing damage to the block layer and suppressing toner slippage, thus preventing cleaning defects. Generally, using low-flowability toner increases torque, but the wrinkle shape on the surface of the photosensitive drum makes it possible to suppress the increase in torque during the cleaning process, achieving a high level of both torque reduction and suppression of cleaning defects.

[0049] As demonstrated by the mechanism described above, the effects of this disclosure can be achieved through the synergistic interaction of the photosensitive drum and the toner components within a process cartridge according to one aspect of this disclosure. The configuration of an electrophotographic photosensitive drum according to one aspect of this disclosure will be described in detail below.

[0050] [Electrophotographic photosensitive drum] An electrophotographic photosensitive drum comprises 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 involves preparing coating solutions for each layer, as described later, applying them in the desired order, and drying them. Methods for applying the coating solutions include immersion coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, and ring coating. Among these, immersion coating is preferred from the viewpoint of efficiency and productivity. The support structure and each layer are 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. The shape of the support can be cylindrical, belt-shaped, or sheet-shaped. Among these, a cylindrical support is preferred. Furthermore, the surface of the support may be subjected to electrochemical treatments such as anodizing, blasting, or cutting. Suitable materials for the support include metal, resin, and glass. Examples of metals include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof. Among these, an aluminum support made of aluminum is preferred. Furthermore, conductivity may be imparted to resins and glass by processing such as mixing or coating them with conductive materials.

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

[0053] Examples of materials for 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, and bismuth oxide. Examples of metals include aluminum, nickel, iron, nichrome, copper, zinc, and silver. Among these, it is preferable to use metal oxides as conductive particles, and it is more preferable to use titanium oxide, tin oxide, or zinc oxide. When using metal oxides as conductive particles, the surface of the metal oxide may be treated with a silane coupling agent or doped with elements such as phosphorus or aluminum, or their oxides. Furthermore, the conductive particles may have a laminated structure comprising core material particles and a coating layer covering those particles. Examples of core material particles include titanium oxide, barium sulfate, and zinc oxide. Examples of the coating layer include metal oxides such as tin oxide. Furthermore, when using metal oxides as conductive particles, their volume-average particle diameter 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 resins include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenolic resin, and alkyd resin. Furthermore, the conductive layer may further contain silicone oil, resin particles, a concealing agent such as titanium dioxide, etc.

[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] A conductive layer can be formed by preparing a coating solution for a conductive layer containing the above-mentioned materials and solvents, forming a coating film, 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. Methods for dispersing conductive particles in the coating solution for a conductive layer include using a paint shaker, sand mill, ball mill, or liquid impaction type high-speed disperser.

[0057] <Underlayer> In the present invention, an undercoat layer may be provided on the support or conductive layer. By providing an undercoat layer, the interlayer adhesion function is enhanced and a charge injection prevention function can be provided.

[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 polymerizable functional groups. Examples of resins include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, epoxy resin, melamine resin, polyurethane resin, phenolic resin, polyvinylphenol resin, alkyd resin, polyvinyl alcohol resin, polyethylene oxide resin, polypropylene oxide resin, polyamide resin, polyamic acid resin, polyimide resin, polyamide-imide resin, and cellulose resin. Polymerizable functional groups found in monomers possessing polymerizable functional groups include isocyanate groups, blocked isocyanate groups, methylol groups, alkylated methylol groups, epoxy groups, metal alkoxide groups, hydroxyl groups, amino groups, carboxyl groups, thiol groups, carboxylic acid anhydride groups, and carbon-carbon double bond groups.

[0059] Furthermore, the undercoat layer may further contain electron transport materials, metal oxides, metals, conductive polymers, etc., for the purpose of improving electrical properties. Among these, electron transport materials and metal oxides are preferred. Examples of electron transport materials include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadienylidene compounds, fluorenone compounds, xanthone compounds, benzophenone compounds, cyanovinyl compounds, aryl halides, silole compounds, and boron-containing compounds. An electron transport material having polymerizable functional groups may be used as the electron transport material, and a base layer may be formed as a cured film by copolymerizing it with the above-mentioned monomers having polymerizable functional groups. Examples of metal oxides include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, and silicon dioxide. Examples of metals include gold, silver, and aluminum. Furthermore, the underlayer may contain additional additives.

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

[0061] The undercoat can be formed by preparing an undercoat coating solution containing the above-mentioned materials and solvents, forming this coating film, and then drying and / or curing it. 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.

[0062] <Photosensitive layer> The photosensitive layers of electrophotographic photosensitive drums are mainly classified into (1) multilayer photosensitive layers and (2) single-layer photosensitive layers. (1) A multilayer photosensitive layer has a charge generating layer containing a charge generating material and a charge transport layer containing a charge transport material. (2) A single-layer photosensitive layer has a photosensitive layer containing both a charge generating material and a charge transport material.

[0063] (1) Stacked photosensitive layer The stacked photosensitive layer comprises a charge generation layer and a charge transport layer.

[0064] (1-1) Charge generation layer The charge generation layer preferably contains a charge generation 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% to 85% by mass, and more preferably 60% to 80% by mass, relative to the total mass of the charge generating layer.

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

[0067] Furthermore, the charge generation layer may contain additives such as antioxidants and ultraviolet absorbers. Specifically, examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, and benzophenone compounds.

[0068] The average thickness of the charge generation layer is preferably 0.1 μm or more and 1 μm or less, and more preferably 0.15 μm or more and 0.4 μm or less.

[0069] The charge generation layer can be formed by preparing a coating solution for the charge generation layer containing the above-mentioned materials and solvents, forming a coating film, 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.

[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 substances. Among these, triarylamine compounds and benzidine compounds are preferred, and those with the following structures are preferably used. [ka] (In formula (1), R 1 ~R 10(Each of these independently represents either a hydrogen atom or a methyl group.)

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

[0072] Thermoplastic resins are used as the resin, including polyester resin, polycarbonate resin, acrylic resin, and polystyrene resin. Among these, polycarbonate resin and polyester resin are preferred. Polyarylate resin is particularly preferred among polyester resins.

[0073] The content of the charge transport material in the charge transport layer is preferably 25% by mass or more and 70% by mass or less, and more preferably 30% by mass or more and 55% by mass or less, 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] Furthermore, the charge transport layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, lubrication agents, and wear resistance enhancers. Specifically, examples 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 5 μm to 50 μm, more preferably 8 μm to 40 μm, and particularly preferably 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 solvents, forming a coating film, and drying it. 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 or aromatic hydrocarbon-based solvents are preferred.

[0078] (2) Single-layer photosensitive layer A single-layer photosensitive layer can be formed by preparing a coating solution for a photosensitive layer containing a charge generating substance, a charge transporting substance, a resin, and a solvent, forming this coating film, and drying it. The charge generating substance, charge transporting substance, and resin are the same as the examples of materials in "(1) Multilayer Photosensitive Layer" above.

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

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

[0081] 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 substances. Among these, triarylamine compounds and benzidine compounds are preferred.

[0082] Examples of resins include polyester resins, acrylic resins, phenoxy resins, polycarbonate resins, polystyrene resins, phenolic resins, melamine resins, and epoxy resins. Among these, polycarbonate resins, polyester resins, and acrylic resins are preferred. The protective layer may also be formed as a cured film by polymerizing a composition containing monomers having polymerizable functional groups. Examples of reactions in this case include thermal polymerization, photopolymerization, and radiation polymerization. Examples of polymerizable functional groups in monomers having polymerizable functional groups include acrylic groups and methacrylic groups. Materials with charge transport ability may be used as monomers having polymerizable functional groups.

[0083] Compounds having polymerizable functional groups may also have charge-transporting structures simultaneously with chain-polymerizable functional groups. Triarylamine structures are preferred as charge-transporting structures. Acryloyl groups and methacryloyl groups are preferred as chain-polymerizable functional groups. The number of functional groups may be one or more. In particular, forming a cured film containing a compound with multiple functional groups and a compound with one functional group is especially preferable because the strain generated by polymerization between the multiple functional groups is easily relieved.

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

[0085] Examples of compounds having the above-mentioned 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, UV absorbers, plasticizers, leveling agents, lubrication agents, and wear resistance enhancers. Specifically, examples 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 protective coating solution containing the above-mentioned materials and solvents, forming this coating film, and then drying and / or curing it. Examples of solvents 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 can be classified into (1) methods for forming wrinkle shapes and (2) methods for forming embossed shapes. (1) Wrinkle shapes are obtained by laminating films with different thermal expansion behaviors and heating and cooling them, forming a pattern like that shown in Figure 1(A). (2) Embossed shapes, as disclosed in Patent Document 3, are formed by pressing a mold made of metal or the like onto the surface of the photosensitive drum, and are widely known as a surface shape imparting technique to photosensitive drums.

[0089] (1)Wrinkle shape The wrinkle shape is formed by first creating a protective layer, which is a crosslinkable cured film, on a charge transport layer mainly composed of thermoplastic resin, and then applying a heat treatment. It is believed that the difference in the amount of deformation between the protective layer and the charge transport layer causes compressive stress in the surface direction, and the surface protective layer buckles, thereby forming the wrinkle shape.

[0090] (2) Embossed shape The method for forming an embossed shape includes an embossed shape transfer step in which a mold member having an embossed shape is pressed into contact with an electrophotographic photoreceptor, thereby transferring the embossed shape of the mold member to the surface of the electrophotographic photoreceptor. At this time, an embossed shape can be formed even with a photoreceptor without a protective layer, but it is preferable to have a protective layer for durability.

[0091] Figure 4 shows an example of a pressure-contact shape transfer processing apparatus for forming recesses on the surface of an electrophotographic photoreceptor. According to the pressure-contact shape transfer processing apparatus shown in Figure 4, a recess can be formed on the surface of the electrophotographic photoreceptor 2-1 by continuously bringing the mold member 2-2 into contact with its surface (circumferential surface) while rotating the workpiece, and applying pressure. Examples of materials for the pressurizing member 2-3 include metal, metal oxide, plastic, and glass. Among these, stainless steel (SUS) is preferred from the viewpoint of mechanical strength, dimensional accuracy, and durability. A mold member is installed on the upper surface of the pressurizing member 2-3. Furthermore, a support member (not shown) and a pressurizing system (not shown) installed on the lower side allow the mold member 2-2 to be brought into contact with the surface of the electrophotographic photoreceptor 2-1, which is supported by the support member 2-4, at a predetermined pressure. Alternatively, the support member 2-4 may be pressed against the pressurizing member 2-3 at a predetermined pressure, or the support member 2-4 and the pressurizing member 2-3 may be pressed against each other.

[0092] The example shown in Figure 4 is one in which the surface of the electrophotographic photoreceptor 2-1 is continuously processed while the electrophotographic photoreceptor 2-1 is driven or rotated by the pressure member 2-3 being moved perpendicular to the axial direction of the electrophotographic photoreceptor 2-1. Furthermore, the surface of the electrophotographic photoreceptor 2-1 can also be continuously processed by fixing the pressure member 2-3 and moving the support member 2-4 perpendicular to the axial direction of the electrophotographic photoreceptor 2-1, or by moving both the support member 2-4 and the pressure member 2-3. Furthermore, from the viewpoint of efficiently transferring the shape, it is preferable to heat the mold member 2-2 and the electrophotographic photoreceptor 2-1.

[0093] Examples of mold members 2-2 include metal or resin films with fine surface processing, silicon wafers with patterns formed on their surfaces using a resist, resin films with dispersed fine particles, and resin films having a fine surface shape that have been coated with a metal. Furthermore, from the viewpoint of making the pressure applied to the electrophotographic photoreceptor 2-1 uniform, it is preferable to install an elastic body between the mold member 2-2 and the pressurizing member 2-3.

[0094] The toner configuration relating to one aspect of this disclosure will be described in detail below. [toner] The method for producing toner particles according to the present invention is not particularly limited as long as it can achieve the above-mentioned fluidity torque, and known manufacturing methods can be used. Among known manufacturing methods, the toner particles of the present invention are preferably those produced by suspension polymerization, which involves dispersing a radically polymerizable monomer and a colorant, then droplet-dispersing them in an aqueous medium or the like to achieve a desired toner particle size, and finally undergoing suspension polymerization. This is because it is possible to form particles with a sharp particle size distribution, high sphericity, and a nearly uniform surface material, making it easier to obtain stable fluidity and excellent electrostatic properties.

[0095] The method for producing toner particles used in the present invention will be described below, with the most suitable suspension polymerization method for obtaining the toner particles being exemplified. Polymerizable monomers, colorants, polar resins, mold release agents, and other additives as needed are uniformly dissolved or dispersed using a disperser such as a homogenizer, ball mill, colloid mill, or ultrasonic disperser, and a polymerization initiator is dissolved in the mixture 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 toner particles are produced by polymerizing the polymerizable monomers in the particles. The polymerization initiator may be added at the same time as other additives are added to the polymerizable monomer, or it may be mixed immediately before dispersing the polymerizable monomer composition in an aqueous medium. Furthermore, polymerizable monomers or polymerization initiators dissolved in a solvent can be added immediately after granulation and before the polymerization reaction begins.

[0097] In the present invention, it is preferable to add a suitable acid to adjust the pH during dispersion, granulation, and before initiating 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 with more uniform charging performance.

[0098] By adding a polar resin during the polymerization reaction from the dispersion step to the polymerization step of the polymerizable monomer composition, the state of the polar resin can be controlled according to the balance of polarity exhibited by the polymerizable monomer composition that becomes the toner particles and the aqueous dispersion medium. In other words, by adding a polar resin, functional separation according to the resin layer becomes possible. Furthermore, toner particles obtained by suspension polymerization are preferable because they have a core-shell structure that encapsulates the mold release agent component. 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 that constitute 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. As the polymerizable monomer constituting the binder resin, a vinyl-based polymerizable monomer capable of radical polymerization can be used. As the vinyl-based polymerizable monomer, a monofunctional polymerizable monomer or a polyfunctional polymerizable monomer can be used. Examples of polymerizable monomers for forming the binder resin include the following: Styrene; styrene 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, diethyl acrylate, aminoethyl, diethylaminoethyl methacrylate; ene monomers such as butadiene, isoprene, cyclohexene, acrylonitrile, methacrylonitrile, acrylamide, and methacrylateamide.

[0100] In this 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: 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-type diacrylate (MANDA Nippon Kayaku), and those in which the above diacrylates are replaced with dimethacrylate. Examples of polyfunctional crosslinking agents include: pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylates and their methacrylates, 2,2-bis(4-methacryloxypolyethoxyphenyl)propane, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, and triallyl trimellitate.

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

[0102] Examples of polymerization initiators used in the toner of the present invention include: azo-based or diazo-based polymerization initiators such as 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonnitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, and azobisisobutyronitrile; and peroxide-based 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 used varies slightly depending on the polymerization method, but it is used alone or in combination, with reference to the 10-hour half-life temperature.

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

[0104] Examples of organic pigments or dyes used as cyanide colorants include copper phthalocyanine compounds and their derivatives, anthraquinone compounds, and basic dye lake compounds. Specifically, the following can be listed: 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 dyes used as magenta colorants include: condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolon compounds, thioindigo compounds, and perylene compounds. Specifically, the following can be listed: 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 dyes used as yellow colorants include compounds such as condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specifically, the following can be mentioned: 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, 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 colored black using the aforementioned yellow-based colorants, magenta-based colorants, and cyan-based colorants.

[0108] These colorants can be used individually, in combination, or even in solid solution form. The colorants used in the toner of the present invention are selected based on their hue angle, saturation, brightness, lightfastness, OHP transparency, and dispersibility in the toner.

[0109] In the present invention, when obtaining toner particles using a polymerization method, attention must be paid to the polymerization inhibitory properties and water phase migration properties of the colorant, and it is preferable to subject the colorant to hydrophobization treatment with a substance that does not inhibit polymerization.

[0110] Known inorganic and organic dispersion stabilizers can be used as the dispersion stabilizers when preparing the aqueous media. Specifically, 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] In addition, the following can be used as organic dispersants: polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose, and starch.

[0112] In addition, commercially available nonionic, anionic, and cationic surfactants can also be used. Examples of such surfactants include: sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium lauryl sulfate, potassium stearate, and calcium oleate.

[0113] As the dispersion stabilizer used when preparing the aqueous medium for the toner of the present invention, an inorganic, poorly water-soluble dispersion stabilizer is preferred, and moreover, a poorly water-soluble inorganic dispersion stabilizer that is soluble in acid is preferred.

[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 is for dispersion. Furthermore, in order to obtain dispersion stabilizer particles having a fine and 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 using tricalcium phosphate as a dispersion stabilizer, a suitable dispersion stabilizer can be obtained by mixing an aqueous sodium phosphate solution and an aqueous calcium chloride solution 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 incorporating a charge control agent, it is possible to improve and stabilize the charge characteristics and control the amount of triboelectric charge to the optimal level according to the developing system. Known charge control agents can be used, and charge control agents that have a fast charging speed and can stably maintain a constant amount of charge are particularly preferred.

[0116] Furthermore, when toner particles are manufactured by direct polymerization, charge control agents that have low polymerization inhibitory properties and produce few solubilizers in aqueous media are particularly preferred. Examples of charge control agents that control the toner's load charge include the following: Organometallic compounds and chelate compounds are effective, including monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, and oxycarboxylic 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 bisphenol. Furthermore, urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, calixarenes, and resin-based charge control agents are also used. Among these, polymers having sulfonic acid-based functional groups as charge control agents are preferably polymers or copolymers having sulfonic acid groups, sulfonic acid bases, or sulfonic acid ester groups.

[0117] Furthermore, one method for controlling the value of E in this invention is to control it by changing the type, amount, and conditions of the inorganic fine particles added to the toner particles.

[0118] [Process cartridges, electrophotographic equipment] The process cartridge according to the present invention 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 characterized by being detachable from the electrophotographic apparatus body.

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

[0120] Figure 2 shows an example of a schematic configuration of an electrophotographic apparatus having a process cartridge equipped with an electrophotographic photosensitive drum. 1 is a cylindrical electrophotographic photosensitive drum, which is rotated at a predetermined peripheral speed in the direction of the arrow around axis 2. The surface of the electrophotographic photosensitive drum 1 is charged to a predetermined positive or negative potential by the charging means 3. In the figure, a roller charging method using a roller-type charging member is shown, but other charging methods such as corona charging, proximity charging, and injection charging may be used. Exposure light 4 is irradiated onto the charged surface of the electrophotographic photosensitive drum 1 from an exposure means (not shown), and an electrostatic latent image corresponding to the desired image information is formed. The electrostatic latent image formed on the surface of the electrophotographic photosensitive drum 1 is developed with toner contained in the developing means 5, and a toner image is formed on the surface of the electrophotographic photosensitive drum 1. The toner image formed on the surface of the electrophotographic photosensitive drum 1 is transferred to a transfer material 7 by the transfer means 6. The transfer material 7 with the transferred toner image is transported to a fixing means 8, undergoes toner image fixing processing, and is printed out outside the electrophotographic device. The electrophotographic device may have a cleaning means 9 for removing toner and other deposits remaining on the surface of the electrophotographic photosensitive drum 1 after transfer. Alternatively, a so-called cleanerless system may be used in which the above-mentioned adhering substances are removed by developing means 5 or the like, without providing a separate cleaning means 9. The electrophotographic apparatus may also have a static elimination mechanism that removes static electricity from the surface of the electrophotographic photosensitive drum 1 with pre-exposure light 10 from pre-exposure means (not shown). Furthermore, guide means 12 such as rails may be provided for attaching and detaching the process cartridge 11 according to the present invention to the electrophotographic apparatus body.

[0121] Electrophotographic photosensitive drums can be used in laser beam printers, LED printers, photocopiers, and other devices. [Examples]

[0122] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited in any way by the following examples, unless it exceeds the gist of the invention. In the following examples, "parts" refers to mass unless otherwise specified.

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

[0124] [Conductive layer] Next, I prepared the following materials. 214 titanium oxide (TiO2) particles (average primary particle size 230 nm) coated with oxygen-deficient tin oxide (SnO2) as a metal oxide particle. • Phenolic resin as a binding material (phenolic resin monomer / oligomer) (product name: Priofen J-325, manufactured by DIC Corporation, resin solids content: 60% by mass) 132 parts 98 parts of 1-methoxy-2-propanol as a solvent These materials were placed in a sand mill using 450 glass beads with a diameter of 0.8 mm, and dispersed under the following conditions: rotation speed: 2000 rpm, dispersion processing time: 4.5 hours, and cooling water temperature set at 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 Co., Ltd., average particle size 2 μm) were added to the obtained dispersion as a surface roughening agent. The amount of silicone resin particles added was set to 10% by mass relative to the total mass of metal oxide particles and binder material in the dispersion after the glass beads were removed. In addition, silicone oil (product name: SH28PA, manufactured by Toray Dow Corning Co., Ltd.) was added to the dispersion as a leveling agent at a concentration of 0.01% by mass relative to the total mass of 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 metal oxide particles, binder, and surface roughening agent (i.e., the mass of solids) in the dispersion was 67% by mass relative to the mass of the dispersion. After that, the mixture was stirred to prepare a coating solution for the conductive layer. This coating solution for the conductive layer was applied to a support by immersion, and the support was heated at 140°C for 1 hour to form a conductive layer with a film thickness of 30 μm.

[0125] [Underlayer] Next, I prepared the following materials. ·4 parts of electron transport material (formula E-1) • Blocked isocyanate (product name: Duranate SBN-70D, manufactured by Asahi Kasei Chemicals Corporation) 5.5 parts • Polyvinyl butyral resin (S-Rec KS-5Z, manufactured by Sekisui Chemical Co., Ltd.) 0.3 parts • Zinc(II) hexanoate (manufactured by Mitsuwa Chemical Co., Ltd.) as a catalyst: 0.05 parts These were dissolved in a mixed solvent of 50 parts tetrahydrofuran and 50 parts 1-methoxy-2-propanol to prepare a coating solution for the undercoat layer. This undercoat solution was applied to the conductive layer by immersion, and the mixture was 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 and 5 parts of polyvinyl butyral resin (product name: S-Rec BX-1, manufactured by Sekisui Chemical Co., Ltd.) were prepared, with peaks at 7.5° and 28.4° in the chart obtained from CuKα characteristic X-ray diffraction. These were added to 200 parts of cyclohexanone and dispersed for 6 hours using a sand mill apparatus with glass beads with a diameter of 0.9 mm. Further dilution was performed by adding 150 parts of cyclohexanone and 350 parts of ethyl acetate to obtain a coating solution for the charge generation layer. The obtained coating solution was immersed and applied onto the undercoat layer, and dried at 95°C for 10 minutes to form a charge generation layer with a film thickness of 0.20 μm.

[0127] The X-ray diffraction measurements were performed under the following conditions. [Powder X-ray diffraction measurement] Measurement equipment used: RINT-TTRII X-ray diffractometer, manufactured by Rigaku Electric Co., Ltd. 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: Used Counter monometer: Not used Divergent slit: Open Divergence vertical limiting slit: 10.00 mm Scattering slit: Open Light-receiving slit: Open Planar monochromator: Used Counter: Scintillation counter

[0128] [Charge transport layer] Next, I prepared the following materials. • 5 parts of the charge-transporting material (hole-transporting material) represented by the above structural formula (1-1) • 5 parts of charge-transporting material (hole-transporting material) represented by the above structural formulas (1-3) • Polycarbonate (product name: Yupiron Z400, manufactured by Mitsubishi Engineering Plastics Corporation) 10 pieces • 0.02 parts of polycarbonate resin having copolymer units of the following structural formulas (C-4) and (C-5) (x / y=0.95 / 0.05: viscosity-average molecular weight=20000) A coating solution for the charge transport layer was prepared by dissolving these materials in a mixed solvent of 60 parts toluene, 2.3 parts methyl benzoate, and 12.8 parts tetrahydrofuran. This coating solution for the charge transport layer was applied to the charge generating layer by immersion to form a coating film, and the coating film was 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, I prepared the following materials. • 8 parts of the compound shown in the above structural formula (2-1) • 16 parts of the compound represented by the above structural formula (3-1) • 0.1 part of siloxane-modified acrylic compound (Cymac US270, manufactured by Toagosei Co., Ltd.) These were mixed with 58 parts cyclohexane and 25 parts 1-propanol and stirred. In this way, a protective coating solution was prepared. The protective coating solution was immersed and applied onto the charge transport layer to form a coating film, and the resulting coating film was dried at 40°C for 5 minutes. Then, under a nitrogen atmosphere, the support (irradiated object) was rotated at a speed of 300 rpm while the electron beam was irradiated onto the coating film for 1.6 seconds under the conditions of an acceleration voltage of 70 kV and a beam current of 5.0 mA. The dose at the outermost layer was 15 kGy. Subsequently, under a nitrogen atmosphere, the temperature was raised from 25°C to 100°C over 20 seconds to perform the first heating, forming a protective layer with a thickness of 1.5 μm. The oxygen concentration from electron beam irradiation to the subsequent heat treatment was 10 ppm or less. Next, the coating film was allowed to cool naturally in air until its temperature reached 25°C, and then a second heat treatment was performed for 15 minutes under the conditions of the coating film reaching 220°C to form a wrinkled shape. In this way, a cylindrical (drum-shaped) electrophotographic photosensitive drum having the protective layer of Example 1 was fabricated.

[0130] [Manufacturing method for photosensitive drum 2] Except for the protective layer thickness being set to 0.5 μm, it was manufactured in the same manner as photosensitive drum 1.

[0131] [Manufacturing method for photosensitive drum 3] Except for the protective layer thickness being set to 0.3 μm, it was manufactured in the same manner as photosensitive drum 1.

[0132] [Manufacturing method for photosensitive drum 4] The device was manufactured in the same manner as photosensitive drum 1, except that after drying the charge transport layer, it was rubbed circumferentially with a nonwoven fabric and then coated with a protective layer. For the abrasion treatment method, Toraysee MK Sheet (manufactured by Toray Industries, Inc.) was used as the nonwoven fabric for abrasion. The nonwoven fabric was kept taut so as not to wrinkle, and the surface of the support, which had the charge transport layer formed on it, was pressed 3 mm from the point where it was just in contact with the sheet. The support was then rotated at 60 rpm for 1 second, abrasion performed in the circumferential direction.

[0133] [Manufacturing method for photosensitive drum 5] Aside from the protective layer thickness being set to 0.5 μm, it was manufactured in the same manner as photosensitive drum 4.

[0134] [Manufacturing method for photosensitive drum 6] Aside from the protective layer thickness being set to 0.3 μm, it was manufactured in the same manner as photosensitive drum 4.

[0135] [Manufacturing method for photosensitive drum 7] The device was manufactured in the same manner as photosensitive drum 1, except that after drying the charge transport layer, it was rubbed longitudinally with a nonwoven fabric and then coated with a protective layer. For the abrasion treatment method, Toraysee MK Sheet (manufactured by Toray Industries, Inc.) was used as the nonwoven fabric for abrasion. The nonwoven fabric was kept taut so as not to wrinkle, and the surface of the support, which had the charge transport layer formed on it, was pressed 3 mm from the point where it was in contact with the sheet, and abrasion was performed in the longitudinal direction.

[0136] [Manufacturing method for photosensitive drum 8] Aside from the protective layer thickness being set to 0.5 μm, it was manufactured in the same manner as the photosensitive drum 7.

[0137] [Manufacturing method for photosensitive drum 9] Aside from the protective layer thickness being set to 0.3 μm, it was manufactured in the same manner as photosensitive drum 7.

[0138] [Manufacturing method for photosensitive drum 10] The manufacturing process was the same as for photosensitive drum 1, except that a second heating process was not performed during the drying stage after the protective layer coating to prevent the formation of wrinkles.

[0139] [Manufacturing method for photosensitive drum 11] A photosensitive drum was prepared by manufacturing the electrophotographic photosensitive drum in Example 1 without performing the second heating process. The surface of this photosensitive drum was polished using the polishing machine shown in Figure 4 under the following conditions. Abrasive sheet feed speed: 400 mm / min Photosensitive drum rotation speed: 240 rpm Abrasive grains: Silicon carbide Average particle size of abrasive grains: 3 μm Polishing time: 20 seconds The polishing method involved a polishing sheet, which consisted of a layer on a sheet-like substrate in which abrasive particles were dispersed in a binding resin, being fed in the direction of the arrow while an electrophotographic photosensitive drum was rotated in the direction of the arrow and pressed against it for 20 seconds to perform a surface roughening treatment.

[0140] <Evaluation of the photosensitive drum> The following evaluations were performed on photosensitive drums 1-5. [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 protrusions having ridge portions within the range of θ from 45 to 135 degrees, and the average value have of the height of the protrusions having ridge portions were determined using 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 or not the electrophotographic photosensitive drum had wrinkles over its entire outer surface. Furthermore, using the method described above, it was confirmed whether the observation area contained one or more wrinkle ridges within the range of θ from 45 to 135 degrees, and whether the observation points within the range of θ from 45 to 135 degrees accounted for the majority of the observation points within the observation area. In all observation areas, the following conditions 1, 2, and 3 were examined. If all conditions were met, the result was A; if conditions 1 and 2 were met, the result was B; if only condition 1 was met, the result was C; and if none of the conditions were met, the result was D. Condition 1: Has mountain-like wrinkles. Condition 2: There exists at least one tangent line that satisfies 45° ≤ θ ≤ 135°. Condition 3: The number of tangents satisfying 45°≦θ≦135° is greater than the number of tangents satisfying θ<45° and 135°<θ. The evaluation results are shown in Table 1.

[0142] [Table 1]

[0143] <Examples of toner manufacturing> The following describes the manufacturing examples of the toner used in the embodiments and comparative examples of the invention. First, we will describe the manufacturing examples of the toner used in the examples and comparative examples of the present invention. In the examples and comparative examples of the present invention, toner particles produced by suspension polymerization were used. However, the toner particles in the present invention are not necessarily limited to this method, and toner particles obtained by pulverization, emulsion polymerization agglutination, or dissolution suspension methods can also be used.

[0144] [Example of toner particle manufacturing] Toner particles 1 were manufactured by suspension polymerization as follows. The following materials were mixed and stirred for 2 hours to dissolve the polar resin, thereby obtaining a monomer composition containing polar resin. • 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℃, acid value=12.0 mgKOH / g]) 5.0 parts by mass • Charge control agent Bontron E-88 (manufactured by Orient Chemical Co., Ltd.) 1.0 part by mass Furthermore, the following materials were mixed and stirred together with zirconia beads (3 / 16 inch) at 200 rpm for 3 hours using an attritor (manufactured by Mitsui Mining Co., Ltd.), and the beads were separated to obtain a colorant dispersion. • Styrene 36.0 parts by mass • Coloring agent: CIPigment Blue 15:3 6.0 parts by mass

[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 the polymerization initiator perbutyl O (manufactured by NOF Corporation) was added, and the mixture was stirred for 5 minutes. Meanwhile, 875 parts by mass of a 0.1 mol / L Na3PO4 aqueous solution and 8.0 parts by mass of 10% hydrochloric acid were added to a container equipped with a high-speed stirrer, Creamix (manufactured by M-Technique), the rotation speed was adjusted to 15,000 rpm, and the mixture was heated to 60°C. 70 parts by mass of a 1.0 mol / L CaCl2 aqueous solution were then added to prepare an aqueous medium containing minute amounts of the poorly water-soluble dispersant Ca3(PO4)2. After adding the polymerization initiator to the polymerizable monomer composition, 5 minutes later, the polymerizable monomer composition at 60°C was added to the aqueous medium heated to 60°C, and granulation was carried out for 15 minutes while rotating the Creamix at 15,000 rpm. Subsequently, the high-speed stirrer was replaced with a stirrer having propeller blades, and the mixture was reacted at 60°C for 5 hours under reflux, after which the liquid temperature was raised to 80°C and the mixture was reacted for another 5 hours. After polymerization was complete, the liquid temperature was lowered to approximately 20°C, and dilute hydrochloric acid was added to lower the pH of the aqueous medium to 3.0 or less, dissolving the poorly water-soluble dispersant. Further washing and drying were performed to obtain toner particles with a weight-average particle size (D4) of 5.96 μm.

[0146] [Example of manufacturing silica nanoparticle 1] In an autoclave with stirring, BET specific surface area 300m 2 Dry silica (average primary particle size = 8 nm) was placed in a nitrogen atmosphere, and 20 parts of dimethyl silicone oil (kinematic viscosity 50 cSt) were added per 100 parts of dry silica. The mixture was then held at 250°C for 30 minutes. After removal, the mixture was crushed to obtain silica fine particles 1.

[0147] [Example of manufacturing silica nanoparticle 2] In a 3 L glass reactor equipped with a stirrer, dropping funnel, and thermometer, 687.9 g of methanol, 42.0 g of pure water, and 47.1 g of 28% by mass aqueous ammonia were added and mixed. The resulting solution was adjusted to 35 degrees Celsius, and 1100.0 g (7.23 mol) of tetramethoxysilane and 395.2 g of 5.4% by mass aqueous ammonia were added simultaneously while stirring. The tetramethoxysilane was added dropwise over 5 hours, and the aqueous ammonia was added dropwise over 4 hours. After the dropwise addition was complete, stirring was continued for another 0.2 hours to carry out hydrolysis, thereby obtaining a suspension of hydrophilic spherical sol-gel silica microparticles. Subsequently, the pH of the prepared suspension was adjusted to approximately 3.5. After 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 filtrate was washed with deionized water and then heated and dried overnight at 120°C. Subsequently, it was crushed using a pulperizer (manufactured by Hosokawa Micron Corporation) to obtain the target silica nanoparticles 2.

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

[0149] <Example of manufacturing from toner 2 to toner 4> In the manufacturing example of Toner 1, Toner 4 was obtained from Toner 2 in the same manner as in the manufacturing example of Toner 1, except that the type and amount of added silica fine particles were changed to those listed in Table 2. The fluidity torque E value of the manufactured toner is also listed in Table 2.

[0150] [Table 2]

[0151] [Example 1] A modified Hewlett-Packard Color LaserJet CP4525nd laser beam printer was used as the electrophotographic device. Modifications were made to allow measurement of the drive current of the photosensitive drum's rotation motor. Furthermore, modifications were made to allow adjustment and measurement of the voltage applied to the charging roller, and adjustment and measurement of the image exposure light intensity. Additionally, the cyan cartridge was modified, the photosensitive drum was replaced with photosensitive drum 1, and the toner was refilled into toner 1. Furthermore, the contact pressure of the CRG cleaning blade against the electrophotographic photosensitive drum was changed to 40% of the product specifications.

[0152] [Examples 2-11, Comparative Examples 1-4] Process cartridges for Examples 2-11 and Comparative Examples 1-4 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 prepared in Examples 1-11 and Comparative Examples 1-4 were evaluated under the following conditions.

[0154] [Relative Torque Evaluation] 100 images were printed on A4-sized plain paper using a test chart with a print ratio of 5%. The charging conditions were a dark area potential of -500V, and the exposure conditions were an image exposure light intensity of 0.25 μJ / cm². 2 The settings were adjusted accordingly. The drive current value (current value A) was read when 100 prints were output. A larger current value indicates greater friction between the electrophotographic photosensitive drum and the cleaning blade. The measured value of a process cartridge using a photosensitive drum 10 and toner 3 without wrinkles on its surface was defined as the current value B and used as a comparison for relative values. The ratio of the drive current value (current value A) to the drive current value (current value B) of the rotating motor of the electrophotographic photosensitive drum obtained in this manner was calculated. The obtained values ​​of (current value A) / (current value B) were compared as relative torque values. A smaller relative value indicates a reduction in the frictional force between the electrophotographic photosensitive drum and the cleaning blade. The evaluation results are shown in Table 3.

[0155] [Evaluation of image lines] Furthermore, the evaluation was performed using halftone images immediately after outputting 1000 horizontal line images with 10 spaces per line. Specifically, the occurrence of streaks (slippage) in the output images, which were considered to be due to cleaning defects, was visually counted and ranked. The evaluation results are shown in Table 3. Rank evaluation of image streaks A: There are no visible lines in the image quality, and the image quality is good. B: Minor streaks may appear. C: Streaks appear in part of the image. D: Streaks appear across the entire image.

[0156] [Evaluation of static charge roller contamination] Toner deposited on the C-roller used for image streaking evaluation was taped, and the toner density was measured using a spectrophotometer X-rite504 (manufactured by X-rite Corporation). The reflectance density value was then used for rank evaluation. A higher number indicates a greater amount of toner adhering to the charging roller. Ranking of dirt on electrostatic rollers A: Less than 0.1. B: 0.1 or higher, but less than 0.2. C: 0.2 or higher, but 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 axes 3. Charging means 4 Exposure light 5. Developing means 6. Transfer means 7 Transfer material 8 Fixing means 9. Cleaning methods 10 Pre-exposure light 11 Process Cartridges 12 Guidance methods

Claims

1. a drum-shaped electrophotographic photoreceptor having a support and a photosensitive layer; a developing means for developing an electrostatic latent image on an outer surface of said electrophotographic photoreceptor with toner; A toner contained in the developing means; a cleaning blade for removing toner from an 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 between the tangent of the ridge of the protrusion 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. A process cartridge according to claim 2, wherein the observation points within said observation region where said θ is within a 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 a circumferential direction of the electrophotographic photosensitive member, the cross-sectional profile is gentle.

5. When the angle between the tangent of the ridge of the protrusion forming the wrinkle and a line parallel to the circumferential direction of the electrophotographic photosensitive member is θ, the average value Lave of the distance between the ridgelines of adjacent convex portions having ridgeline portions in which θ is within a 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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