JP2007086320A - Electrophotographic photoreceptor and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical electrophotographic photoreceptor which improves vibration, warpage and edge defects of a cleaning blade when a cleaning member is set in a specific position, and which improves image defects such as image deletion and toner fusion in long-term use in a high temperature and high humidity environment, and to provide an image forming method using the photoreceptor. <P>SOLUTION: A peripheral surface of the cylindrical electrophotographic photoreceptor has a plurality of dimple-shaped concavities, ten-point average roughnesses Rzjis(A) and (B) measured by sweeping in a peripheral direction and a generatrix direction of the peripheral surface of the cylindrical electrophotographic photoreceptor are 0.3-2.5 μm, average spacings RSm(C) and (D) of concavities and convexities measured by sweeping in a peripheral direction and a generatrix direction of the peripheral surface of the cylindrical electrophotographic photoreceptor are both 5-120 μm, and the ratio (D/C) of the average spacing RSm(D) of concavities and convexities to the average spacing RSm(C) of concavities and convexities is 0.5-1.5. The image forming method using the photoreceptor is also provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrophotographic photoreceptor. The present invention also relates to an image forming method, and more particularly to an image forming method using the electrophotographic photosensitive member.

  Conventionally, inorganic photoconductive materials such as selenium, cadmium sulfide and zinc oxide have been widely used for electrophotographic photoreceptors. On the other hand, as an electrophotographic photosensitive member using an organic photoconductive substance, a photoconductive polymer represented by poly-N-vinylcarbazole and 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadi Those using a low molecular organic photoconductive substance such as azole, and those obtained by combining such an organic photoconductive substance with various dyes and pigments are known.

  An electrophotographic photosensitive member using an organic photoconductive substance has a good film forming property and can be produced by coating. Therefore, the productivity is extremely high, and an inexpensive electrophotographic photosensitive member can be provided. In addition, it has an advantage that the photosensitive wavelength range can be freely controlled by selecting the dye or pigment to be used, and has been extensively studied so far. In particular, the development of a functionally-separated type photoreceptor in which a charge generation layer containing an organic photoconductive dye or pigment and a charge transport layer containing a photoconductive polymer or a low-molecular charge transport material are laminated has recently been developed. Significant improvements have been made in the sensitivity and durability that have been regarded as disadvantages of organic electrophotographic photoreceptors, and this has become the mainstream of electrophotographic photoreceptors.

  On the other hand, as a matter of course, the electrophotographic photosensitive member is required to have sensitivity, electrical characteristics, optical characteristics and the like according to the applied electrophotographic process. In particular, in the case of a photoreceptor that is used repeatedly, electrical and mechanical external forces such as charging, image exposure, toner development, transfer to a transfer medium, and cleaning of residual toner are directly applied to the surface of the photoreceptor. Therefore, durability against them is required. Specifically, durability against surface wear and scratches caused by rubbing, surface deterioration due to charging, such as deterioration of transfer efficiency and slipping, and further deterioration of electrical characteristics such as sensitivity deterioration and charging ability. Sex is required.

  In general, the structure of the organic electrophotographic photosensitive member is a thin resin layer, and the characteristics of the resin material are very important. In recent years, acrylic resins and polycarbonate resins have been put to practical use as resins that satisfy the above-mentioned conditions to some extent, but not all of the above-described properties are satisfied with these resins. In particular, it is difficult to say that the coating film strength of the resin is sufficiently high in order to increase the durability of the photoreceptor. Even when these resins are used as the resin for forming the surface layer, there is a problem in that the surface layer is worn during repeated use and further scratches are generated. Furthermore, due to the recent demand for higher sensitivity of organic electrophotographic photoreceptors, a relatively large amount of a low molecular weight compound such as a charge transport material is often added to the photoreceptor. In this case, the film strength is remarkably lowered due to the plasticizer action of these low molecular weight substances, and there is a problem of wear of the surface layer and generation of scratches during repeated use. Further, when the electrophotographic photosensitive member is stored for a long period of time, the above-described low molecular weight component is precipitated, causing a problem of phase separation.

  As means for solving these problems, an attempt to use a curable resin as a resin for a charge transport layer is disclosed in, for example, Patent Document 1. Thus, by using a curable resin as the resin for the charge transport layer and curing and crosslinking the charge transport layer, the mechanical strength is increased, and the wear resistance and scratch resistance during repeated use are greatly improved. However, even when a curable resin is used, since the low molecular weight component acts as a plasticizer in the binder resin, the problems of precipitation and layer separation as described above have not been fundamentally solved. In addition, in the charge transport layer composed of the organic charge transport material and the binder resin, the charge transport ability is highly dependent on the resin. For example, a curable resin having a sufficiently high hardness does not have a sufficient charge transport ability and is repeatedly used. The residual potential has been increased during use, and both have not been satisfied. In Patent Document 2, Patent Document 3, and the like, the charge transport layer contains a monomer having a carbon-carbon double bond, and reacts with the carbon-carbon double bond of the charge transport material by heat or light energy. An electrophotographic photoreceptor having a cured transport layer film is disclosed. However, the charge transport material is only fixed in a pendant form to the polymer main skeleton, and the mechanical strength is not sufficient because the plastic action cannot be sufficiently eliminated. Further, if the concentration of the charge transport material is increased to improve the charge transport function, the crosslink density is decreased and sufficient mechanical strength cannot be ensured. Furthermore, there is a concern that the initiators required at the time of polymerization may adversely affect the electrophotographic characteristics.

  As another solution, for example, Patent Document 4 discloses an electrophotographic photosensitive member in which a charge transporting layer is formed by introducing a group having a charge transporting ability into a thermoplastic polymer main chain. However, it is effective for precipitation and layer separation compared to conventional molecular dispersion type charge transport layers, and mechanical strength is improved, but it is a thermoplastic resin, and its mechanical strength is limited. is there. It is not a material that is easy to use in terms of handling and productivity including resin solubility.

  For the purpose of improving these problems, Patent Document 5 and Patent Document 6 etc. irradiate an electron beam to a hole transporting compound having a chain polymerizable functional group in the same molecule and / or the hole transporting compound. Thus, it has been proposed to achieve both high mechanical strength and charge transportability by using a photoreceptor containing a polymerized and cured product.

  The electrophotographic photoreceptor undergoes repeated processes such as charging, exposure, development, transfer, cleaning, and charge removal in the image forming process. In particular, the cleaning process for removing the residual toner on the photoconductor after the transfer process is an important process for obtaining a clear image. As a cleaning method, first, a rubber-like plate-shaped member called a cleaning blade is pressed against the photosensitive member to eliminate a gap between the photosensitive member and the cleaning blade, thereby preventing toner from slipping out and remaining toner. The method of scraping is mentioned. Secondly, a method is also used in which the fur brush roller is rotated so as to contact the photosensitive member to wipe off or knock off the remaining toner. Of these cleaning methods, the rubber blade is advantageous in terms of cost and ease of design, and at present, cleaning using the cleaning blade dominates.

  However, a cleaning blade exhibiting excellent cleaning properties has a drawback that chattering or peeling of the cleaning blade is likely to occur because of a large frictional force with the photoreceptor. Here, chattering of the cleaning blade is vibration of the blade due to an increase in frictional resistance with the photosensitive member. Meklet is a phenomenon in which the blade is inverted and warped in the moving direction of the photosensitive member.

  These problems of the cleaning blade are more likely to occur when the strength of the surface of the photoconductor is increased, that is, it is difficult to scrape the photoconductor in order to extend the life of the photoconductor. Also, when the toner particle size is made uniform to improve the image quality and minute toner is removed, the lubricity caused by the toner entering the gap between the cleaning blade and the photoreceptor surface is reduced. Problems related to cleaning are more likely to occur.

  In addition, when performing color development, since a plurality of developments such as magenta, cyan, yellow, black, etc. are performed to produce a single image, the load on the cleaning blade is increased, the blade is reversed, and further In this case, the defect of the edge portion is more likely to occur.

  As a method of overcoming the problems related to the surface property of the photoconductor in this way, the surface area of the photoconductor is appropriately roughened to reduce the contact area between the surface of the photoconductor and the cleaning blade, thereby improving various problems. A method has been proposed.

  For example, Patent Document 7 discloses that when the surface roughness of the surface layer of the photoconductor is within a specified range, the adhesion between the photoconductor and the transfer material is reduced to facilitate separation, and further when the photoconductive layer is formed. A method of roughening the surface of the photoreceptor to a rough skin shape by controlling the drying conditions is disclosed.

  In this method, since the surface is roughened in the normal photosensitive layer forming process, new equipment is basically unnecessary, but there are many factors to be controlled other than the drying temperature and the drying time. For example, it is difficult to obtain reproducibility in the rough state of the surface of the photoreceptor unless the volatile content of the coating material during coating, the coating atmosphere temperature and humidity, the air flow during coating, and the like are precisely controlled.

  Patent Document 8 also discloses a roughening method by adding powder particles to the surface layer in advance. However, in general, when powder is added to the photoreceptor, there are few materials suitable for the photoreceptor in terms of powder material and dispersibility, and the addition amount may adversely affect the characteristics of the photoreceptor, particularly the sharpness of the image. It can be said that there are many restrictions.

  Patent Document 9 discloses a method for obtaining a rough surface by polishing the surface of a photoreceptor using a metal wire brush as a mechanical roughening process. In this method, when the brush is used continuously, there is a problem that it is difficult to obtain reproducibility due to deterioration of the brush tip and adhesion of abrasive powder to the tip.

  As a prior art in which the surface layer of the organic photoreceptor is roughened, Patent Document 10 discloses. It is described that it is possible to improve problems such as reversal of the cleaning blade and chipping of the edge portion, which are problems when used in an electrophotographic apparatus having a specific process speed or higher by using a specific cleaning means and a specific toner.

  Japanese Patent Application Laid-Open No. H11-228561 discloses a technique for defining the surface roughness of the surface of the photoreceptor to improve toner transfer efficiency. However, this is basically an example of use with an inorganic photoreceptor.

  As another method of mechanical roughening, Patent Document 12 describes a production method in which a film-like abrasive is used for polishing. In this method, it is possible to obtain the reproducibility of the roughening by allowing the new surface of the film-like abrasive to always be used for polishing by the film winding device. However, the film-like abrasive is disadvantageous in that the cost is high and the time required for polishing is long, and there is a problem in the productivity of the roughening process.

  Patent Document 13 shows the roughening of the photoreceptor by the blast method, but the shape of the surface layer of the photoreceptor obtained by this is not described in detail, and the photoreceptor surface layer is cured. Combination with a photoreceptor using a photosensitive resin is not shown.

  In addition, there is a prior art relating to roughening of a photoreceptor having an organic photosensitive layer and a surface protective layer as in Patent Document 14. However, it is a photoconductor prepared in the step of forming the surface protective layer after roughening the surface of the organic photosensitive layer before forming the surface protective layer, and there are problems in productivity, electrophotographic characteristics, etc. It is a structure of a photoreceptor.

  As described above, in recent years, there has been a demand for higher durability and higher image quality for electrophotographic photosensitive members. In response to such demands, techniques for forming a curable resin instead of a plastic resin on the surface layer have been established.

  An organic photoreceptor containing a curable resin in the surface layer has the property that the surface layer hardly wears even during long-term durable use, and the shape of the initial surface layer is maintained during durable use. In particular, a photoreceptor having a surface layer formed by a dip coating method has a very smooth surface layer. Therefore, when the surface layer contains a curable resin, a roughening treatment is essential.

  There is no prior art that describes the construction of an optimum surface layer for such a photoreceptor containing a curable resin in the surface layer.

Under such circumstances, the above-mentioned prior art has achieved a technique that fully satisfies the conditions for forming an optimum surface layer for the roughening of a photoreceptor containing a curable resin in the surface layer. In particular, it has been demanded to establish conditions for producing such a photoreceptor.
JP-A-2-127852 JP-A-5-216249 Japanese Patent Laid-Open No. 7-72640 JP-A-8-248649 JP 2000-66424 A JP 2000-66425 A JP-A-53-92133 JP-A-52-26226 JP-A-57-94772 JP-A-1-99060 JP-A-1-142734 Japanese Patent Laid-Open No. 2-139666 JP-A-2-150850 Japanese Patent No. 2990788

  In recent years, in order to reduce the size of the apparatus and shorten the discharge time of the first sheet, an image forming apparatus having a configuration in which a transfer material is conveyed from bottom to top in the vertical direction is employed as shown in FIG. In such an image forming apparatus, the cleaning unit is configured to face downward, and as shown in FIG. 4, the tip position of the cleaning blade as the cleaning unit is a cylinder center angle A (the cylinder center axis vertically above 0 ° is a cylinder). The rotation direction of the electrophotographic photosensitive member is positive) is, for example, 25.8 degrees. In the figure, T is toner.

  When the image carrier 1 is rotationally driven in the direction indicated by the arrow R, the surface of the image carrier 1 is uniformly charged by the charging means 2. This charged portion is subjected to optical image exposure L by an optical signal generator means (not shown) to form an electrostatic latent image. When the electrostatic latent image passes through the developing means 3, it is visualized by the visible toner. The toner image formed in this way is transferred onto the transfer material 7 by the transfer means 4, and the transfer material 7 that has finished the transfer is separated from the image carrier 1 and is fixed by the fixing means 8 and discharged after fixing (non-loading roller). Discharged).

  The toner remaining without being transferred adheres to the surface of the image carrier 1 after the transfer as described above, and this toner T is scraped off by the cleaning means 5 in contact with the surface of the image carrier 1. Is done.

  Since the cleaning means 5 is downward, the toner T stays in the image carrier 1 and the cleaning means according to gravity. The cleaning unit 5 has a screw for discharging the staying toner, but if a large amount of images with a high printing ratio is passed, the amount of staying toner exceeds the toner discharging ability of the screw. Therefore, if the toner T continues to accumulate as it is, not only the cleaning cannot be performed sufficiently, but also the toner T overflows outside the cleaning device. In order to prevent these problems, it is necessary to increase the set pressure of the cleaning means for the image carrier. However, problems such as chattering of the cleaning blade, scratches, and missing edge portions are likely to occur.

  It is an object of the present invention to provide a cylindrical electrophotographic photosensitive member and an image forming method in which the outermost surface layer of the electrophotographic photosensitive member has an optimum surface shape, thereby causing chattering, cleaning, Improve edge defects. Another object of the present invention is to improve image defects such as image flow and toner fusion when used endurancely under high temperature and high humidity.

  In particular, when using an electrophotographic photosensitive member using a curable resin improved in the outermost layer for improving durability of the photosensitive member and improving the strength of the outermost layer and having a high elastic deformation rate. In addition, the above-mentioned problems that are particularly prominent are to be steadily improved from the initial printing to printing of a large number of sheets.

  The present invention comprises a cylindrical electrophotographic photosensitive member comprising at least a support and an organic photosensitive layer, wherein the surface of the photosensitive member has a surface shape having dimple-like irregularities.

That is, the present invention relates to a cylindrical electrophotographic photosensitive member having a cylindrical support and an organic photosensitive layer provided on the cylindrical support.
The peripheral surface of the cylindrical electrophotographic photosensitive member has a plurality of dimple-shaped recesses, and the ten-point average roughness Rzjis (A) measured by sweeping in the circumferential direction of the peripheral surface of the cylindrical electrophotographic photosensitive member is 0. The ten-point average roughness Rzjis (B) measured by sweeping in the generatrix direction (rotational axis direction) of the peripheral surface of the cylindrical electrophotographic photosensitive member is 0.3 to 2.5 μm. The average interval RSm (C) of the unevenness measured by sweeping in the circumferential direction of the peripheral surface of the cylindrical electrophotographic photosensitive member is 5 to 120 μm, and the generatrix direction of the peripheral surface of the cylindrical electrophotographic photosensitive member The average interval RSm (D) of the unevenness measured by sweeping in the direction of the rotation axis is 5 to 120 μm, and the value of the ratio of the average interval RSm (C) of the unevenness to the average interval RSm (D) of the unevenness ( D / C) is a cylindrical electrophotographic photosensitive member characterized by being 0.5 to 1.5

  The ten-point average roughness Rzjis (A) is 0.4 to 2.0 μm, the ten-point average roughness Rzjis (B) is 0.4 to 2.0 μm, and the average interval RSm of the irregularities. (C) is 10 to 100 μm, the average interval RSm (D) of the unevenness is 10 to 100 μm, and the ratio value of the average interval RSm (C) of the unevenness to the average interval RSm (D) of the unevenness ( The cylindrical electrophotographic photosensitive member having a D / C) of 0.8 to 1.2 is preferable.

  The maximum peak height Rp (F) of the peripheral surface of the cylindrical electrophotographic photosensitive member is 0.6 μm or less, and the maximum peak depth Rv (E) of the peripheral surface of the cylindrical electrophotographic photosensitive member is the maximum. The cylindrical electrophotographic photosensitive member having a ratio value (E / F) to the peak height Rp (F) of 1.2 or more is preferable.

  The maximum peak height Rp (F) of the peripheral surface of the cylindrical electrophotographic photosensitive member is 0.4 μm or less, and the ratio value of the maximum valley depth Rv (E) to the maximum peak height Rp (F). The cylindrical electrophotographic photosensitive member having (E / F) of 1.5 or more is preferable.

The number of the dimple-shaped recesses having the longest diameter in the range of 1 to 50 μm and the depth in the range of 0.1 to 2.5 μm is the cylindrical electrophotographic photosensitive member. The cylindrical electrophotographic photosensitive member is preferably 5 to 50 per 10000 μm ^{2 on} the peripheral surface of the body.

  The total area of the dimple-shaped recesses having the longest diameter in the range of 1 to 50 μm and the depth in the range of 0.1 to 2.5 μm is the cylindrical electrophotographic image. The cylindrical electrophotographic photosensitive member is preferably 3 to 60% with respect to the total area of all the dimple-shaped concave portions existing on the peripheral surface of the photosensitive member.

  The average aspect ratio of the dimple-shaped recesses having the longest diameter in the range of 1 to 50 μm and the depth in the range of 0.1 to 2.5 μm among the dimple-shaped recesses is 0.50 to The cylindrical electrophotographic photoreceptor having a value of 0.95 is preferred.

Further, the cylindrical electrophotographic photosensitive member having a universal hardness value (HU) of 150 to 220 N / mm ² on the peripheral surface of the cylindrical electrophotographic photosensitive member is preferable.

  The cylindrical electrophotographic photosensitive member is preferably an elastic deformation rate of 44% to 65% on the peripheral surface of the cylindrical electrophotographic photosensitive member.

  The surface layer of the photoreceptor includes a curable resin, and the curable resin is one type selected from an acrylic resin, a phenol resin, an epoxy resin, a silicone resin, and a urethane resin. A photographic photoreceptor is preferred.

  Further, an electrophotographic photosensitive member in which the curable resin of the surface layer of the photosensitive member is a cured product of a curable resin having a charge transport function is preferable, and the cured product further includes a hole transporting compound having a polymerizable functional group. An electrophotographic photosensitive member obtained by curing by polymerization and / or crosslinking by means of heating and / or radiation irradiation is more preferable.

  Further, the surface layer of the photoconductor includes a curable resin having a charge transport function, and the curable resin is a cured product of a hole transportable compound having two or more chain polymerizable functional groups in the same molecule. An electrophotographic photosensitive member, which is cured using radiation and the radiation is an electron beam, is preferable.

  The layer structure of the photoconductor is a structure in which at least a charge generation layer and a charge transport layer are laminated in this order from the support side, and an electrophotographic photosensitive material containing a cured product of a hole transport compound in the charge transport layer. And an electrophotographic photosensitive member in which the charge transport layer is a laminated type of a non-curable first layer and a curable second layer, and the curable second layer is the outermost surface layer.

Furthermore, according to the present invention, the tip position of the cleaning blade is such that the cylinder center angle A (the vertical direction of the cylinder center axis is 0 degree and the rotation direction of the cylindrical electrophotographic photosensitive member is positive) is −30 degrees to 50 degrees. Within the range, the cylindrical electrophotographic photosensitive member that is in contact with the cylindrical electrophotographic photosensitive member and is disposed so that the central axis of the cylinder is substantially horizontal has a photosensitive layer, and is in an environment of 25 ° C. and 50% humidity. The hardness test was performed using a Vickers square pyramid diamond indenter, the universal hardness value (HU) pushed in at a maximum load of 6 mN was 150 N / mm ² or more and 220 N / mm ² or less, and the elastic deformation rate (Wo) was 44. % To 65% charging step of charging the image carrier, a latent image forming step of forming an electrostatic latent image on the charging surface of the cylindrical electrophotographic photosensitive member, and a toner carried on the toner carrier Transfer the image A developing step for forming an image, a transfer step for transferring the toner image formed on the image carrier to a transfer material with or without an intermediate transfer member, and the surface of the cylindrical electrophotographic photosensitive member In a method of forming an image having a cleaning process in which a cleaning blade made of an elastic member is brought into contact with the photosensitive member to remove transfer residual toner remaining on the photosensitive member, the peripheral surface of the cylindrical electrophotographic photosensitive member is An image forming method having a plurality of dimple-shaped recesses.

  Furthermore, in the present invention, the cylindrical electrophotographic photosensitive member and at least one means selected from the group consisting of a charging means, a developing means and a cleaning means are integrally supported and detachable from the main body of the electrophotographic apparatus. A process cartridge having a certain characteristic is preferably used.

  Further, in the present invention, an electrophotographic apparatus comprising the cylindrical electrophotographic photosensitive member, a charging unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit is preferably used.

  Furthermore, in the present invention, there is provided a method for producing the cylindrical electrophotographic photosensitive member, wherein the outermost layer forming step of forming the outermost layer of the cylindrical electrophotographic photosensitive member, and the surface of the outermost layer is dry-blasted or A method of manufacturing a cylindrical electrophotographic photosensitive member is preferably used, which has a recess forming step of forming a dimple-shaped recess on the surface of the outermost layer by wet honing.

  When the method for forming the outermost surface layer is applied by dip coating, the above manufacturing method is effective. After the outermost surface layer is applied and formed, the surface is roughened from above. .

  According to the present invention, the cleaning member is in a specific arrangement, and the outermost surface layer of the photosensitive layer is in a specific surface shape, so that the contact pressure of the cleaning blade is high or low. There is no occurrence of chattering of the cleaning blade, scratches, slipping of toner, defective cleaning, etc., and no occurrence of streak-like image defects resulting from roughening, and the latitude of the cleaning setting can be widened. In addition, it is possible to provide a cylindrical electrophotographic photosensitive member and an image forming method that do not cause streak-like image defects due to toner fusion or surface roughening, which are likely to occur during durable use under high temperature and high humidity.

  Especially when using an electrophotographic photoreceptor using a curable resin as the outermost surface layer, which improves the strength of the surface layer with the aim of increasing the durability of the photoreceptor and has a high elastic deformation rate. The above-mentioned point can be effectively improved from the initial stage in the durable use of printing a large number of sheets.

  In order to effectively improve the above problems, the present inventors have intensively studied. As a result, the arrangement of the specific cleaning member and the specific surface of the electrophotographic photosensitive member are provided with a specific dimple shape as described above. It was found that such problems can be effectively improved.

  That is, the specific arrangement of the cleaning member means that the tip position of the cleaning blade has a cylinder center angle A (0 degree in the vertical direction of the cylinder center axis and 0 degrees in the rotation direction of the cylindrical electrophotographic photosensitive member). It is necessary to be within the range of 50 degrees or more.

  The dimple shape shown in the present invention is a photoconductor having a fine uneven shape on the surface of the organic electrophotographic photoconductor. In particular, the surface is preferably processed so as to have more dents than the reference surface before roughening. The concave portions exist as isolated as possible, and the concave and convex shape on the surface of the photoconductor has an appropriate roughness, an appropriate concave and convex interval, and an appropriate ratio of the convex portions to the concave portions. It is preferable that the portion is formed so as not to have directionality.

  The photoreceptor of the present invention has a cylindrical shape that can be used repeatedly in an electrophotographic apparatus, has a rotating shaft, and repeats an electrophotographic process such as charging, image exposure, development, transfer, and cleaning while rotating. Used while. The cleaning blade is usually arranged in parallel to the rotation axis of the photoconductor and is in contact with the surface layer of the photoconductor. Therefore, the circumferential direction means a direction perpendicular to the rotation axis, and is a direction in which the photosensitive member is repeatedly brought into contact with each process member.

  In the present invention, it is a requirement to use an organic photoreceptor. Organic photoreceptors are usually suitable for roughening their film thickness, elastic properties, etc. after film formation on the photoreceptor. By controlling the roughening conditions, the surface shape to be finally used Can be controlled in a wide range. In particular, a photoconductor having an elastic deformation rate measured from the surface of the photoconductor within the range of the present invention can give a particularly good surface shape.

  The surface roughening technique of the present invention is an effective technique for forming a photoreceptor having excellent durability characteristics. In particular, a photoconductor having a high elastic deformation rate is excellent in durability, and even when used for a long period of time, there is little change in the initial surface shape and the shape tends to be maintained. It is important to optimally control the surface shape of such a photoreceptor from the initial stage.

  Particularly preferable values of the elastic deformation rate shown in the present invention are in the ranges shown below. The elastic deformation ratio was measured from the top surface of the photoreceptor before roughening.

  Here, the elastic deformation rate Wo% is continuously applied to a Vickers square pyramid diamond indenter having a facing angle of 136 ° in an environment of 25 ° C. and humidity 50% RH using a microhardness measuring device Fischerscope H100V (manufactured by Fischer). It is a value measured by applying a load of 6 mN and directly reading the indentation depth under the load. Specifically, measurement is performed in stages (273 points with a holding time of 0.1 S for each point) up to a final load of 6 mN. An outline of an output chart of the Fischer scope H100V (Fischer) is shown in FIG. In FIG. 1, the vertical axis represents the load (F (mN)), and the horizontal axis represents the indentation depth (h (μm)).

  The elastic deformation rate can be obtained from the work (energy) performed by the indenter on the membrane, that is, the change in energy due to the increase or decrease of the load on the membrane of the indenter, and specifically obtained from the following equation (1). it can.

        Elastic deformation rate = Wo / Wt (1)

  In the above formula, the total work Wt (nJ) indicates the area surrounded by A-B-D-A in FIG. 1, and the elastic deformation work Wo (nJ) is the area surrounded by C-B-D-C. Is shown.

  In the present invention, the elastic deformation rate Wo% needs to be 44% or more and 65% or less. When the elastic deformation rate on the surface of the photoreceptor is less than 44%, the change in the surface shape after repeated use becomes large, and even if the surface is properly roughened, the surface shape cannot be maintained long, and the effect of the surface roughening lasts long. Disappear. In particular, when the surface is roughened by blasting, uneven protrusions formed by the collision of particles with the surface increase, and the occurrence of image defects increases.

  When the elastic deformation rate Wo% is in the region of 44% or more, on the contrary, the change in the surface shape after repeated use becomes small, and the roughening of the present invention becomes more effective. Here, when the outermost surface layer of the photoreceptor is a layer containing a curable resin, the value of the elastic deformation rate is approximately 44% or more.

  In the present invention, any film forming method or roughening method may be used as long as the above dimple shape can be formed on the outermost surface layer.

  However, it is effective to use some mechanical roughening method to obtain the surface shape as required in the present invention. Among the various mechanical surface roughening methods, the dry blast method and the wet honing method are preferable as the method for forming the dimple shape. Furthermore, it is more preferable to use a dry blasting method because an electrophotographic photosensitive member sensitive to humidity conditions can be roughened without contacting with a solvent such as water.

  As a method of blasting, there are a method of injecting using compressed air, a method of injecting using a motor as power, etc., but it is possible to precisely control the roughening of the photoconductor and in terms of simplicity of equipment. A method using compressed air is preferred.

  Examples of the material of the abrasive used for blasting include ceramic systems such as aluminum oxide, zirconia, silicon carbide, and glass, metal systems such as stainless steel, iron, and zinc, and resin systems such as polyamide, polycarbonate, epoxy, and polyester. In particular, glass, aluminum oxide, and zirconia are preferable from the viewpoint of roughening efficiency and cost.

  An example of a blasting apparatus used in the present invention is shown in FIG. The abrasive stored in the container (not shown) is guided to the nozzle through the path 2-4, and is jetted from the jet nozzle 2-1 using the compressed air introduced through the path 2-3. It collides with the photoconductor 2-7 supported by 2-6 and rotating. 2-5 is a blast abrasive grain.

  At this time, the distance between the nozzle and the work is determined by adjusting the nozzle fixing jig and arm 2-2 and 2-9. The nozzle normally performs the roughening process while moving in the direction of the rotation axis of the work, and the nozzle support 2-8 moves in the direction of the rotation axis of the work to perform the roughening process on the work without unevenness. be able to.

  At this time, it is necessary to adjust the shortest distance between the nozzle and the surface of the photoreceptor to an appropriate interval. If the distance is too close or too far, the processing efficiency may decrease, or the desired roughening may not be performed. It is necessary to adjust the pressure of the compressed air used for the power of injection to an appropriate pressure. Thus, a production method with good productivity can be established by roughening the organic photoreceptor after film formation.

  The surface shape or roughening of the present invention is independent of the surface shape of the conductive substrate underlying the photoreceptor. In particular, when the method for forming the organic photosensitive layer is a dip coating method, the surface on which the film is formed is often very smooth, and even if the base is roughened, the surface shape is not reflected.

  When the dimple-like surface shape of the present invention is formed by subjecting it to mechanical surface roughening, it is possible to roughen the surface of the photoconductor from the outermost surface layer after forming the organic photoconductor to the final use layer. preferable.

  In the measurement method of the surface shape, in the present invention, the ten-point average roughness (Rzjis), the average interval of unevenness (RSm), the maximum peak height (Rp), and the maximum valley depth (Rv) are described in JIS-B0601-2001. This is measured according to the method.

  The measurement was performed using a surface roughness measuring instrument (trade name: Surfcorder SE3500 type, manufactured by Kosaka Laboratory Ltd.).

  The surface roughness of the photoreceptor to be roughened needs to be 0.3 μm to 2.5 μm in terms of the ten-point average roughness Rzjis in both cases measured in the circumferential direction and the rotation axis direction. It is preferable that it is 4 micrometers-2.0 micrometers. When the surface roughness is less than 0.3 μm, the improvement effect of the present invention due to the roughening cannot be obtained, and when it exceeds 2.5 μm, the roughness obtained from the roughening appears in the obtained image, and from the cleaning blade More toner slips through.

  The surface shape required in the present invention is a shape having a large number of isolated recesses as close to a circle as possible, which can be expressed as a so-called dimple shape. This dimple shape preferably has no directionality in all directions on the surface of the photoreceptor.

  In the irregularities on the surface of the photoconductor, when the valleys are continuous in a streak shape, low resistance substances such as charged products accumulate in the streaks, especially when used for a long time under high temperature and high humidity. The problem of streak-like image defects due to the occurrence of this is likely to occur. This streak-like image defect is a particularly significant problem in a photoreceptor having the elastic deformation rate Wo% of 44% or more and a photoreceptor capable of achieving high durability containing a curable resin on the surface.

  Accordingly, it can be derived from the surface roughness measurement data that Rzjis, RSm, etc. measured in all directions do not become greatly different depending on the measurement direction. Therefore, the ratio of the value of RSm (C) in the circumferential direction of the peripheral surface to the value of RSm (D) in the bus line direction (axial direction in which the photoconductor rotates) of the peripheral surface is preferably closer to 1.

  The average unevenness interval RSm is 5 μm to 120 μm in both cases measured in the circumferential direction and the generatrix direction, and the ratio of the average unevenness interval RSm (D) in the circumferential direction to the average interval RSm (C) of unevenness (D / C) = 0.5 to 1.5 is required.

  Further, RSm is preferably 10 to 100 μm in both cases measured in the circumferential direction and the busbar direction, and the ratio is (D / C) = 0.8 to 1.2.

  In particular, when the surface of the photosensitive member and the cleaning blade come into contact with each other with a speed difference, there is an optimum uneven distance range. If RSm is smaller than 5 μm, the effect of roughening cannot be obtained. There are many cleaning defects.

  Further, the surface shape of the present invention is intended to have a shape that has a concave portion more positively than a convex portion. When there are many convex shapes on the photoconductor and the height of the convex portion increases, local resistance to the cleaning blade increases, and the edge of the cleaning blade tends to be lost particularly when used for a long period of time. It is in.

  Therefore, in the present invention, the maximum peak height Rp (F) is preferably 0.6 μm or less in order to selectively form a shape in which the height of the convex portion is reduced and the depth of the concave portion is increased. More preferably, it is preferably 0.4 μm or less. Further, the ratio value (E / F) of the maximum valley depth Rv (E) to the maximum peak height Rp (F) is preferably 1.2 or more, more preferably 1.5 or more. Demonstrate.

  The result of examining these dimple shapes in more detail will be described. The dimple shape was measured using a surface shape measurement system (Surface Explorer SX-520DR model, manufactured by Ryoka System Co., Ltd.).

  In the measurement, first, a drum sample was placed on a work table, tilted to adjust the level, and three-dimensional shape data on the surface of the photoreceptor was captured in a wave mode. At that time, the objective lens was observed by visual field observation of 100 μm × 100 μm using 50 × magnification. Next, surface contour data was displayed using a particle analysis program in the data analysis software.

Hole analysis parameter for obtaining the shape of the dimple, the area or the like, maximum diameter limit: visible and screen dimples were observed at 1 [mu] m ³ or more: 50 [mu] m, maximum diameter lower limit: 1 [mu] m, the depth lower limit: 0.1 [mu] m, the volume lower limit The number of parts was counted. Observation was performed with a field of view of 100 μm × 100 μm, and the number of dimples was counted by counting the number of dimples visible in the field of view of the analysis screen.

The area ratio of the dimple is obtained by summing up the area of the dimple portion with the calculated value of the particle analysis software, assuming that the total area is 10000 μm ^{2 under the} same visual field and the same analysis conditions as described above, and (total dimple area / total area) × 100 (%).

  The average aspect ratio of the dimples was determined by collecting the data of dimples that can be identified from the same visual field and the same analysis conditions as described above, and calculating the average value of the aspect ratios.

The number of dimples suitable for the photoreceptor of the present invention is preferably 5 to 50, more preferably 5 to 40 per 10,000 μm ² . A preferable dimple area ratio is 3 to 60%, and more preferably 3 to 50%. Even if the number and area ratio of these dimples exceed the upper limit or less than the lower limit, it is difficult to obtain a roughened effect.

  A preferable average aspect ratio of the dimples is 0.5 to 0.95. When the aspect ratio is below the lower limit, image flow is likely to occur under high temperature and high humidity.

  In the present invention, an isolated dimple-like unevenness having a shape close to a circle is shown, which preferably has a surface shape that conforms to the specifications of the number, area ratio, and average aspect ratio. By having such a shape, it has an appropriate rough surface shape and is a rough surface having no directionality, so that the improvement effect of the present invention can be efficiently obtained for the reasons described before and after. .

  The photoreceptor having the surface shape of the present invention is most effective when applied to a photoreceptor containing a curable resin in the outermost surface layer. Photoreceptors containing a curable resin in the outermost surface layer have little surface wear when used for durability, and the surface shape remains the same between the initial and endurance use, and the optimal surface shape formed in the initial stage is maintained over a long period of time. The initial cleaning characteristics can be maintained even when many sheets are used.

  A photoconductor containing a curable resin in the surface layer has a small amount of shaving of the surface layer, so that the image flow caused by the decrease in the resistance of the surface layer due to accumulation of charged products in the surface layer is a major problem. It becomes. Furthermore, the problem becomes remarkable especially under high temperature and high humidity.

  In particular, when the surface shape is too smooth, the charged product accumulated on the entire surface remains on the entire surface, so that the electrostatic latent image flows as a whole and the image becomes unclear. When the surface is roughened in a streak shape, since the concave portions are continuous, the surface can flow an electrostatic latent image in a streak shape, and a streak-like image defect occurs.

  In order to solve this problem, the dimple shape having an isolated recessed portion of the present invention is effective. Even if the charged product adheres to the surface, the recessed portion does not spread in a specific direction, so that the electrostatic latent image does not flow and disappear. A convex portion as a reference surface is provided in a range of several tens of μm in all directions from the bottom portion of the dent. The reference surface is rubbing against the cleaning blade, etc., and the charged product is hard to accumulate because the charged product is scraped off. It can be suppressed.

  In the present invention, the curable layer on the surface of the photoreceptor includes a monomer or oligomer having a polymerizable functional group in the coating material for producing the photoreceptor, and after the film is formed and dried, the film is heated and irradiated with radiation. This is achieved by forming a tough film-forming layer that is insoluble and infusible in a solvent or the like by three-dimensionally cross-linking and curing by providing a step for proceeding polymerization.

  In the present invention, the outermost layer containing a curable resin may or may not have a charge transport function. If it has a charge transport function, it is treated as a part of the photosensitive layer. If it does not have a charge transport function, it is called a protective layer (or surface protective layer) as described below to distinguish it from the photosensitive layer. Yes.

  In the best constitution of the present invention, it is preferable to obtain a photosensitive layer having a hardened surface by applying a coating containing a charge transporting material having a polymerizable functional group in the same molecule, and then curing the coating. In order to further increase the strength of the hardened layer of the outermost surface layer, it is preferable that two or more polymerizable functional groups exist in the same molecule.

  As the layer structure of the photosensitive layer, a normal layer stack structure in which the charge generation layer / charge transport layer are stacked in this order from the conductive support side, and a reverse layer stack structure in which the charge transport layer / charge generation layer is stacked in this order from the conductive support side. Alternatively, any configuration of a single layer in which the charge generation material and the charge transport material are dispersed in the same layer can be employed.

  In a single photosensitive layer, photocarriers are generated and moved in the same layer, and the photosensitive layer itself is a surface layer. On the other hand, the laminated photosensitive layer has a structure in which a charge generation layer for generating photocarriers and a charge transport layer for moving the generated carriers are laminated.

  The most preferable layer structure is a normal layer structure in which the charge generation layer / charge transport layer are laminated in this order from the conductive support side.

  In this case, the charge transport layer is an electrophotographic photosensitive member that is an outermost surface layer containing a curable resin, or the charge transport layer is a laminated type of a non-curable first layer and a curable second layer. Any of the electrophotographic photoreceptors in which the curable second layer is the outermost surface layer is preferable.

  In either case of a single layer or a laminated layer, it is possible to provide a protective layer above the photosensitive layer. In this case, the protective layer is preferably a curable resin-containing layer on the surface.

  The support of the electrophotographic photosensitive member of the present invention is a metal or alloy such as iron, copper, gold, silver, aluminum, zinc, titanium, lead, nickel, tin, antimony, indium, or an oxide of the metal, carbon, Conductive polymers can be used. The shape includes a drum shape such as a cylindrical shape and a columnar shape, and a belt shape and a sheet shape. The conductive material may be molded as it is, used as a paint, deposited, or processed by etching or plasma treatment. In the case of paint, the support can be made of paper, plastic, etc. as well as the metal and alloy.

  Furthermore, it is preferable to provide a conductive layer for the purpose of preventing interference fringes due to scattering when the support is coated with unevenness or defects on the support, and when the image input is laser light. This can be formed by dispersing conductive powder such as carbon black, metal particles, and metal oxide in a binder resin.

  Further, an undercoat layer may be provided between the conductive support or the conductive layer and the photosensitive layer. The undercoat layer functions as a charge injection control or an adhesive layer at the interface. The undercoat layer is mainly composed of a binder resin, but may contain the metal or alloy, or an oxide, salt or surfactant thereof. Specific examples of the binder resin for forming the undercoat layer include polyester, polyurethane, polyacrylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin, Examples include allyl resin, alkyd resin, polyamide-imide, nylon, polysulfone, polyallyl ether, polyacetal, and butyral resin. The thickness of the undercoat layer is preferably 0.05 to 7 μm, more preferably 0.1 to 2 μm.

  When the photosensitive layer of the present invention has a layer structure of a function-separated type photosensitive layer, a charge generation layer and a charge transport layer are laminated. However, the order of film formation is not particularly limited.

  In the present invention, a general material can be used as the charge generation material. In general, selenium-tellurium, pyrylium, thiapyrylium dyes, and various central metals and crystal systems, specifically, phthalocyanine compounds having crystal types such as α, β, γ, ε, and X type, anant Examples include anthrone pigments, dibenzpyrenequinone pigments, pyranthrone pigments, trisazo pigments, disazo pigments, monoazo pigments, indigo pigments, quinacridone pigments, asymmetric quinocyanine pigments, and quinocyanine and A-Si.

  In addition to the charge generation material, a binder resin can also be used. Specific examples of the binder resin include polyester, polyurethane, polyacrylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, polyamide. -Imido, polysulfone, polyallyl ether, polyacetal, butyral resin, benzal resin and the like.

  When the charge generation layer contains a binder resin, the ratio of the charge generation material to the binder resin is a mass ratio, and the mass ratio of the charge generation material to the binder resin + charge generation material is preferably 0.1 to 100%. More preferably, it is 10 to 80%.

  The thickness of the charge generation layer is preferably 0.001 to 6 μm, and more preferably 0.01 to 2 μm. The mass ratio of the charge generation material contained in the entire charge generation layer is preferably 10 to 100%, more preferably 50 to 100%.

  Examples of charge transport materials include pyrene compounds, N-alkylcarbazole compounds, hydrazone compounds, N, N-dialkylaniline compounds, diphenylamine compounds, triphenylamine compounds, triphenylmethane compounds, pyrazoline compounds, styryl compounds, stilbene compounds, etc. Is mentioned.

  In addition to the charge transport material, a binder resin can also be used. Specific examples of the binder resin include polyester, polyurethane, polyacrylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, and the like.

  When a charge transport layer is used on the outermost surface, a resin or monomer that cures and polymerizes using a high-energy beam or the like, and further uses a resin or monomer that cures and polymerizes with a hole transport function. Is possible.

  When the charge transport layer contains a binder resin, the ratio of the charge transport material to the binder resin is a mass ratio, and the mass ratio of the charge transport material to the binder resin + charge transport material is preferably 0.1 to 100%. More preferably, it is 10 to 80%.

  If the thickness of the charge transport layer is too thin, the charging ability cannot be maintained. Preferably it is 5-70 micrometers, More preferably, it is 5-30 micrometers.

  The amount of the charge transport material contained in the charge transport layer is preferably 20 to 100% by mass ratio, more preferably 30 to 90%.

  When the photosensitive layer is used as a single layer, the charge generation material and the charge transport material are contained in the same layer. Specific examples of the charge generating material and the charge transporting material are the same as those in the case of the laminated photoconductor. Similarly, it is possible to use a resin or monomer that cures and polymerizes using radiation, and further a resin or monomer that cures and polymerizes having a hole transport function.

  The single photosensitive layer preferably has a thickness of 8 to 40 μm, more preferably 12 to 30 μm. The photoconductive material such as a charge generation material or a charge transport material is preferably contained in an amount of 20 to 100% by mass, more preferably 30 to 90% by mass.

When a protective layer is provided on the outermost surface, the film thickness is preferably 0.01 to 10 μm, more preferably 0.1 to 7 μm. It is possible to use a resin or monomer that cures and polymerizes using radiation. Further, the protective layer may contain a conductive material such as a metal and its oxide, nitride, salt, alloy or carbon. Examples of such metal species include iron, copper, gold, silver, lead, zinc, nickel, tin, aluminum, titanium, antimony, and indium. Specifically, ITO, TiO ₂ , ZnO, SnO ₂ Al ₂ O ₃ or the like can be used. The conductive material is dispersed in the protective layer in the form of fine particles, but the particle diameter is preferably 0.001 to 5 μm, more preferably 0.01 to 1 μm, and the amount added to the protective layer Is preferably 1 to 70 mass%, more preferably 5 to 50 mass%. A titanium coupling agent, a silane coupling agent, various surface activities, and the like may be used as the dispersant.

  Various additives such as an antioxidant and a photodegradation inhibitor may be used for each layer constituting the photosensitive layer. Further, the surface layer may contain various fluorine compounds, silane compounds, metal oxides or the like or fine particles thereof for the purpose of improving the lubricity and water repellency. A dispersant or a surfactant may be used for the purpose of improving these dispersibility. The content of these additives in the surface layer is preferably 1 to 70% by mass, more preferably 5 to 50% by mass.

  As a method for producing the electrophotographic photosensitive member of the present invention, methods such as vapor deposition and coating are used, but the coating method is most preferable. The coating method can form films having various compositions in a wide range from a thin film to a thick film. Specifically, it is applied by a bar coater, knife coater, dip coating, spray coating, beam coating, electrostatic coating, roll coater, attritor or the like.

  FIG. 3 shows a schematic configuration example of a general transfer type electrophotographic apparatus using the electrophotographic photosensitive member of the present invention.

  In FIG. 3, reference numeral 1 denotes a cylindrical photoconductor of the present invention as an image carrier, which is driven to rotate at a predetermined peripheral speed in the direction of an arrow about an axis 1a. The photosensitive member 1 is uniformly charged with a predetermined positive or negative potential on its peripheral surface by the charging means 2 during the rotation process, and then is exposed to light image exposure (slit exposure, laser beam scanning exposure, etc.) by the image exposure means L in the exposure section. ) As a result, electrostatic latent images corresponding to the exposure image are sequentially formed on the peripheral surface of the photosensitive member.

  The electrostatic latent image is then supplied with toner from the developing sleeve 3-1 by the developing unit 3, and the developed toner image is transferred from the sheet feeding unit (not shown) to the photosensitive member 1 and the transfer unit 4 by the transfer unit 4. In the meantime, the image is sequentially transferred onto the surface of the transfer material 7 taken out in synchronization with the rotation of the photosensitive member 1 and fed.

  The transfer material 7 that has received the image transfer is separated from the surface of the photosensitive member, introduced into the image fixing means 8, and subjected to image fixing, and is output to the outside as a copy (copy).

  The surface of the photoreceptor 1 after the image transfer is cleaned by receiving the toner remaining after the transfer by the cleaning means 5, and further subjected to a charge removal process by the pre-exposure means 6 and repeatedly used for image formation.

  Among the above-described components such as the photosensitive member, developing means, and cleaning means, a plurality of components are integrally combined as an apparatus unit, and this unit is a process cartridge configured to be detachable from the apparatus body. May be. For example, the photosensitive member 1 and the cleaning unit 5 may be integrated into one device unit, and may be configured to be detachable by using a guide unit such as a rail of the device body. At this time, the apparatus unit may be configured with a charging unit and / or a developing unit.

  When the electrophotographic apparatus is used as a copying machine or a printer, the optical image exposure L is a reflected light or transmitted light from an original or a reading signal of the original, and this signal scans a laser beam, drives an LED array, Alternatively, it is performed by driving a liquid crystal shutter array. When used as a facsimile printer, the optical image exposure L is an exposure for printing received data.

  The electrophotographic photosensitive member of the present invention can be used not only in electrophotographic copying machines but also widely in electrophotographic application fields such as laser beam printers, CRT printers, LED printers, liquid crystal printers, and laser plate making.

  Next, the present invention will be described in detail with reference to examples. However, the present invention is not limited to these examples.

[Example 1]
The electrophotographic photoreceptor used in Example 1 was produced as follows. First, an aluminum cylinder (JIS A3003 aluminum alloy) having a length of 370 mm, an outer diameter of 30 mm, and a thickness of 0.7 mm was prepared by cutting. When the surface roughness of this cylinder was measured in the direction of the rotation axis, Rzjis = 0.08 μm. This cylinder is subjected to ultrasonic cleaning in pure water containing a detergent (trade name: Chemicol CT, manufactured by Tokiwa Chemical Co., Ltd.), followed by washing out the detergent, followed by ultrasonic cleaning in pure water. And degreased.

  60 parts by mass of titanium oxide powder (trade name: Kronos ECT-62, manufactured by Titanium Industry Co., Ltd.) having a coating film of tin oxide doped with antimony, titanium oxide powder (trade name: titone SR-1T, 堺Chemical Co., Ltd.) 60 parts by mass, resol type phenol resin (trade name: Phenolite J-325, Dainippon Ink & Chemicals, Inc., solid content 70%) 70 parts by mass, 2-methoxy-1-propanol A solution consisting of 50 parts by mass and 50 parts by mass of methanol was dispersed with a ball mill for about 20 hours. The average particle size of the filler contained in this dispersion was 0.25 μm.

  The dispersion prepared in this manner was applied on the aluminum cylinder by the dipping method, and was heated and dried for 48 minutes in a hot air drier adjusted to 150 ° C. to form a conductive layer having a thickness of 15 μm. .

  Next, 10 parts by mass of a copolymer nylon resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) and 30 parts by mass of a methoxymethylated nylon resin (trade name: Toresin EF30T, manufactured by Teikoku Chemical Industry Co., Ltd.) were added to methanol 500. A solution dissolved in a mixed solution of parts by mass and 250 parts by mass of butanol is dip-coated on the conductive layer, put in a hot air drier adjusted to 100 ° C. for 22 minutes, dried by heating, and a film thickness of 0. A subbing layer of 45 μm was formed.

  Next, 4 parts by mass of a hydroxygallium phthalocyanine pigment having strong peaks at 7.4 ° and 28.2 ° with a Bragg angle of 2θ ± 0.2 ° in CuKa characteristic X-ray diffraction, polyvinyl butyral resin (trade name: ESREC BX-) (1) Sekisui Chemical Co., Ltd.) 2 parts by mass and 90 parts by mass of cyclohexanone were dispersed in a sand mill for 10 hours using glass beads having a diameter of 1 mm, and then 110 parts by mass of ethyl acetate was added to form a charge generation layer. A coating solution was prepared. This coating solution was dip-coated on the undercoat layer, put into a hot air dryer adjusted to 80 ° C. for 22 minutes, and dried by heating to form a charge generation layer having a thickness of 0.18 μm.

  Next, 35 parts by mass of a triarylamine compound represented by the following structural formula (11)

And a coating for a charge transport layer prepared by dissolving 50 parts by mass of bisphenol Z-type polycarbonate resin (trade name: Iupilon Z400, manufactured by Mitsubishi Engineering Plastics) in 320 parts by mass of monochlorobenzene and 50 parts by mass of dimethoxymethane The solution was dip-coated on the charge generation layer, placed in a hot air dryer adjusted to 100 ° C. for 40 minutes, and dried by heating to form a first charge transport layer having a thickness of 18 μm.

  Next, 27 parts by mass of a hole transporting compound having a polymerizable functional group represented by the following structural formula (12),

0.45 parts by mass of fluorine atom-containing resin (trade name: GF-300, manufactured by Toagosei Co., Ltd.) as a dispersant, 1,1,2,2,3,3,4-heptafluorocyclopentane (trade name) : Zeolola H, manufactured by Nippon Zeon Co., Ltd.) and 35 parts by mass of 1-propanol, and then tetrafluoroethylene resin powder (trade name: Lubron L-2, Daikin Industries, Ltd.) as a lubricant. 3 parts by mass are added, and a high-pressure disperser (trade name: Microfluidizer M-110EH, manufactured by Microfluidics, USA) is subjected to 3 treatments at a pressure of 5880 N / cm ² (600 kgf / cm ² ) and uniformly dispersed. I let you. This was subjected to pressure filtration with a 10 μm PTFE membrane filter to prepare a lubricant dispersion. Thereafter, 27 parts by mass of the hole transporting compound represented by the formula (12) is added to the lubricant dispersion, and pressure filtration is performed with a PTFE 5 μm membrane filter, and the second charge transport as a curable surface layer is performed. The layer coating solution was adjusted. Using this coating solution, a second charge transport layer was applied as a curable surface layer on the first charge transport layer by a dip coating method.

  Thereafter, an electron beam was irradiated in nitrogen under conditions of an acceleration voltage of 150 kV and a dose of 4.5 kGy. Subsequently, a heat treatment was performed for 90 seconds under the condition that the temperature of the photoconductor was 120 ° C. The oxygen concentration at this time was 10 ppm. Further, the photoconductor was subjected to a heat treatment for 20 minutes in a hot air dryer adjusted to 100 ° C. in the atmosphere to form a curable surface layer having a thickness of 5 μm.

  For the hardness test, the photoconductor was allowed to stand in an environment of 23 ° C. and 50% humidity for 24 hours, and then the elastic deformation rate was determined using the above-described microhardness measuring device Fischerscope H100V (Fischer).

  The elastic deformation rate is obtained by continuously applying hardness to the indenter and directly reading the indentation depth under the load. As the indenter, a Vickers quadrangular pyramid diamond indenter having a facing angle of 136 ° can be used. Specifically, measurement is performed in stages (273 points with a holding time of 0.1 S for each point) up to a final load of 6 mN.

  The measurement was carried out before blasting the outermost layer. The measurement results are shown in Table 1.

  The obtained photoreceptor was subjected to a surface roughening treatment as follows. Using a dry blasting apparatus (manufactured by Fuji Seiki Co., Ltd.) shown in FIG. 2, blasting was performed under the following conditions.

Abrasive abrasive grains: spherical glass beads having an average particle size of 30 μm (trade name: UB-01L, manufactured by Union Co., Ltd.) was used. Air spray pressure: 35.28 N / cm ² , Blast gun moving speed: 430 mm / min, Workpiece (photoconductor) rotation speed: 288 rpm, Blast gun discharge port to photoconductor distance: 100 mm, Abrasive discharge angle: 90 °, Abrasive grain supply amount: 200 g / min, blasting frequency: one way × 2 times

  Further, the abrasive material remaining on the surface of the photoreceptor was removed by blowing compressed air.

  When the surface shape of the outermost surface layer of this electrophotographic photosensitive member was measured, the values shown in Table 1 were obtained. The measurement was performed using a surface roughness measuring device (trade name: Surfcorder SE3500 type, manufactured by Kosaka Laboratory Ltd.). The measurement of Rzjis and RSm in the circumferential direction of the photoconductor was performed using the circumferential roughness measuring device for the above-mentioned apparatus. Measurement conditions were as follows: measurement length: 0.4 mm, measurement speed: 0.1 mm / s. The baseline level setting value for noise cut at the time of RSm measurement was measured at level setting = 10%.

  In the present invention, ten-point average roughness (Rzjis), average interval of unevenness (RSm), maximum peak height (Rp), and maximum valley depth (Rv) were measured according to the method described in JIS-B0601-2001. Say.

In addition, the surface shape measuring system (Surface Explorer SX-520DR type machine, Ryo Co., Ltd.) in which the number of dimples per 10000 μm ² of the surface layer of the photoreceptor, the area ratio of dimples, and the average aspect ratio of dimples are described above. The measurement and calculation were performed using a product made by Kasei System.

  These results are shown in Table 1.

  The electrophotographic photoreceptor thus obtained was evaluated using an electrophotographic copying machine (trade name: iR4570, manufactured by Canon Inc.) equipped with a polyurethane rubber cleaning blade.

  The photoconductor was mounted on this copying machine, and the characteristics such as potential and image were evaluated as follows. In an environment of 23 ° C./50% RH, the potential conditions are such that the dark portion potential (Vd) and the light portion potential (Vl) of the photoreceptor are Vd = −720 (V) and Vl = −220 (V), respectively. And the initial potential of each photoconductor to be evaluated was adjusted.

  As an evaluation of the cleaning property, the cleaning property was evaluated when the contact pressure setting of the cleaning blade was set to two conditions of high pressure and low pressure. The linear pressure of the high pressure setting blade was 392 mN / cm, and the low pressure setting blade linear pressure was 196 mN / cm. The setting angle of the cleaning blade was set to 25.8 °.

  The evaluation environment was 23 ° C./50% RH, and the results were compared while evaluating the endurance of 100,000 A2 test images intermittently. A defect on the image was observed by outputting a test image such as a halftone image after the endurance evaluation.

  In the blade high pressure setting, the drum rotation torque was monitored from the current value of the motor when the blade was used for durability, and the occurrence of blade squealing and blade curl was evaluated.

  The blade linear pressure is set to 392 mN / cm, and the B / A value is obtained from the initial driving current value A of the rotating motor of the photosensitive member and the driving current value B after the endurance of 100,000 sheets as a relative torque increase ratio. Compared. This value is also shown in Table 2.

  When the durability was evaluated at a blade low pressure setting (blade linear pressure of 196 mN / cm), the occurrence of cleaning failure due to toner slipping from the blade was evaluated.

  The above photoreceptor exhibits good cleaning characteristics under any conditions, there is almost no increase in torque during rotation of the photoreceptor even when the blade is set at high pressure, there is no occurrence of blade squealing, stagnation, etc. Even in the setting, there was no occurrence of image defects such as toner slipping.

  The image flow under HH environment was evaluated separately.

  As an evaluation of image flow in a high temperature and high humidity environment, the above-described electrophotographic apparatus was installed in an environment of 30 ° C./80% RH, the blade linear pressure was set to 294 mN / cm, and the A4 horizontal size two-sheet intermittent mode was set to 10 After producing a durable image by copying all the durable image patterns, a sample image such as a halftone image was output to evaluate the occurrence of the image flow. The photoconductor having the surface shape of the present invention obtained very good results with respect to the occurrence of image flow.

  For evaluation of the rubbing memory, the electrophotographic photosensitive member to be evaluated is mounted on the electrophotographic apparatus used in the above evaluation in an environment of 23 ° C./5% RH, the pre-exposure is turned off in the dark, and the primary charging is turned off. Then, with the developing unit and the primary transfer unit separated from each other, the photosensitive drum and the cleaning blade were rubbed against each other by rotating idly for 15 minutes while the cleaning blade was in contact. This was left for 60 minutes, and the difference between the initial and accumulated potentials was measured and compared to obtain the value of the rubbing memory.

  Since the outermost surface layer of the photoconductor of the present invention is roughened to an appropriate roughness, there is little frictional resistance on the surface of the photoconductor, and even when rubbing against members around the photoconductor, there are no adverse effects due to rubbing. It is hard to occur. As a result, an excellent result was obtained that the rubbing memory accumulated on the photosensitive member was very small.

  The evaluation results are shown in Table 2. As shown in Table 2, the electrophotographic photosensitive member of the present invention has no cleaning failure such as toner slipping when the blade contact pressure is low, and the blade contact pressure is high regardless of the setting of the cleaning conditions. In this case, an electrophotographic photosensitive member can be obtained which does not have blade squealing, blade peeling, and drum torque increase. In addition, even when a large number of sheets are printed for a long time under high temperature and high humidity conditions, image defects such as image flow are difficult to occur, and further, the photosensitive member is rubbed with a blade or the like during pre-rotation without charging or pre-exposure. An electrophotographic photosensitive member that provides a stable image that is positively charged and does not cause accumulated rubbing memory.

[Example 2]
In the production of the photoreceptor of Example 1, up to the second charge transport layer was produced in the same manner as in Example 1. Next, in the roughening treatment of Example 1, the roughening treatment was performed in the same manner as in Example 1 except that the air spraying pressure condition was changed to 11.76 N / cm ² .

  The prepared photoreceptor was mounted on the same electrophotographic apparatus as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Example 3]
In the production of the photoreceptor of Example 1, up to the second charge transport layer was produced in the same manner as in Example 1. Next, in the roughening treatment of Example 1, the roughening treatment was performed in the same manner as in Example 1 except that the air blowing pressure condition was changed to 17.64 N / cm ² .

  The prepared photoreceptor was mounted on the same electrophotographic apparatus as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Example 4]
In the production of the photoreceptor of Example 1, up to the second charge transport layer was produced in the same manner as in Example 1. Next, in the roughening treatment of Example 1, the roughening treatment was performed in the same manner as in Example 1 except that the air blowing pressure condition was changed to 23.52 N / cm ² .

  The prepared photoreceptor was mounted on the same electrophotographic apparatus as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Example 5]
In the production of the photoreceptor of Example 1, up to the second charge transport layer was produced in the same manner as in Example 1. Next, in the roughening treatment of Example 1, the roughening treatment was performed in the same manner as in Example 1 except that the air spraying pressure condition was changed to 29.4 N / cm ² .

  The prepared photoreceptor was mounted on the same electrophotographic apparatus as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Example 6]
In the production of the photoreceptor of Example 1, up to the second charge transport layer was produced in the same manner as in Example 1. Next, in the roughening treatment of Example 1, the roughening treatment was performed in the same manner as in Example 1 except that the air blowing pressure condition was changed to 41.16 N / cm ² .

  The prepared photoreceptor was mounted on the same electrophotographic apparatus as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Example 7]
In the production of the photoreceptor of Example 1, the charge generation layer was produced in the same manner as in Example 1. Next, a single-layer charge transport layer that is curable as a whole is provided as a charge transport layer.

  70 parts by mass of a hole transporting compound having a polymerizable functional group represented by the structural formula (12) was mixed with 15 parts by mass of 1-propanol and 1,1,2,2,3,3,4-heptafluorocyclopentane ( (Zeorolla H) After dissolving in 15 parts by mass, pressure filtration was performed with a PTFE 0.5 μm membrane filter to prepare a charge transport layer coating solution as a curable surface layer.

  This coating solution was applied onto the charge generation layer by a dip coating method. Thereafter, an electron beam was irradiated in nitrogen under conditions of an acceleration voltage of 150 kV and a dose of 4.5 kGy. Subsequently, a heat treatment was performed for 90 seconds under the condition that the temperature of the photoconductor was 120 ° C. The oxygen concentration at this time was 10 ppm. Further, the photosensitive member was heat-treated in a hot air dryer adjusted to 100 ° C. in the atmosphere for 20 minutes to form a curable surface layer having a thickness of 10 μm.

  The value of Wo% measured from the surface of the photoreceptor was measured in the same manner as in Example 1. The roughening treatment of the outermost surface layer was performed by the same dry blast treatment as in Example 1.

  The prepared photoreceptor was mounted on the same electrophotographic apparatus as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Example 8]
In the production of the photoreceptor of Example 1, the charge generation layer was produced in the same manner as in Example 1. Next, a single-layer charge transport layer that is curable as a whole is provided as a charge transport layer.

  70 parts by mass of a hole transporting compound having a polymerizable functional group represented by the structural formula (12) was mixed with 15 parts by mass of 1-propanol and 1,1,2,2,3,3,4-heptafluorocyclopentane ( (Zeorolla H) After dissolving in 15 parts by mass, pressure filtration was performed with a PTFE 0.5 μm membrane filter to prepare a charge transport layer coating solution as a curable surface layer.

  This coating solution was applied onto the charge generation layer by a dip coating method. Thereafter, an electron beam was irradiated in nitrogen under conditions of an acceleration voltage of 150 kV and a dose of 1.5 kGy. Subsequently, a heat treatment was performed for 90 seconds under the condition that the temperature of the photoconductor was 120 ° C. The oxygen concentration at this time was 10 ppm. Further, the photosensitive member was heat-treated in a hot air dryer adjusted to 100 ° C. in the atmosphere for 20 minutes to form a curable surface layer having a thickness of 10 μm.

  The value of Wo% measured from the surface of the photoreceptor was measured in the same manner as in Example 1. The roughening treatment of the outermost surface layer was performed by the same dry blast treatment as in Example 1.

  The prepared photoreceptor was mounted on the same electrophotographic apparatus as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Example 9]
In the production of the photoreceptor of Example 1, up to the second charge transport layer was produced in the same manner as in Example 1. Next, a roughening treatment was performed in the same manner as in Example 1.

  The prepared photosensitive member mounted on a process cartridge modified so that the cylindrical center angle A is 50 degrees was mounted on the same electrophotographic apparatus as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Example 10]
In the production of the photoreceptor of Example 1, up to the second charge transport layer was produced in the same manner as in Example 1. Next, a roughening treatment was performed in the same manner as in Example 1.

  The prepared photosensitive member mounted on a process cartridge modified so that the cylindrical center angle A is −30 degrees was mounted on the same electrophotographic apparatus as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Comparative Example 1]
For the photoreceptor prepared in Example 1, the surface shape and the like were measured without subjecting the outermost surface layer to blasting, and mounted on the electrophotographic apparatus used in Example 1 and evaluated in the same manner. The results are shown in Tables 1 and 2.

[Comparative Example 2]
In the production of the photoreceptor of Example 1, up to the second charge transport layer was produced in the same manner as in Example 1. Next, in the roughening treatment of Example 1, the roughening treatment was performed in the same manner as in Example 1 except that the air blowing pressure condition was changed to 5.88 N / cm ² .

  The prepared photoreceptor was mounted on the same electrophotographic apparatus as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Comparative Example 3]
In the production of the photoreceptor of Example 1, up to the second charge transport layer was produced in the same manner as in Example 1. Next, in the roughening treatment of Example 1, the roughening treatment was performed in the same manner as in Example 1 except that the air blowing pressure condition was changed to 47.04 N / cm ² .

  The prepared photoreceptor was mounted on the same electrophotographic apparatus as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Comparative Example 4]
In the production of the photoreceptor of Example 1, the charge generation layer was produced in the same manner as in Example 1. Next, a single-layer charge transport layer that is curable as a whole is provided as a charge transport layer.

  70 parts by mass of a hole transporting compound having a polymerizable functional group represented by the structural formula (12) was mixed with 15 parts by mass of 1-propanol and 1,1,2,2,3,3,4-heptafluorocyclopentane ( (Zeorolla H) After dissolving in 15 parts by mass, pressure filtration was performed with a PTFE 0.5 μm membrane filter to prepare a charge transport layer coating solution as a curable surface layer.

  This coating solution was applied onto the charge generation layer by a dip coating method. Thereafter, an electron beam was irradiated in nitrogen under conditions of an acceleration voltage of 150 kV and a dose of 6.0 kGy. Subsequently, a heat treatment was performed for 90 seconds under the condition that the temperature of the photoconductor was 120 ° C. The oxygen concentration at this time was 10 ppm. Further, the photosensitive member was heat-treated in a hot air dryer adjusted to 100 ° C. in the atmosphere for 20 minutes to form a curable surface layer having a thickness of 10 μm.

  The value of Wo% measured from the surface of the photoreceptor was measured in the same manner as in Example 1. The roughening treatment of the outermost surface layer was performed by the same dry blast treatment as in Example 1.

  The prepared photoreceptor was mounted on the same electrophotographic apparatus as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Comparative Example 5]
In the production of the photoreceptor of Example 1, the charge generation layer was produced in the same manner as in Example 1. Next, a single-layer charge transport layer that is curable as a whole is provided as a charge transport layer.

  70 parts by mass of a hole transporting compound having a polymerizable functional group represented by the structural formula (12) was mixed with 15 parts by mass of 1-propanol and 1,1,2,2,3,3,4-heptafluorocyclopentane ( (Zeorolla H) After dissolving in 15 parts by mass, pressure filtration was performed with a PTFE 0.5 μm membrane filter to prepare a charge transport layer coating solution as a curable surface layer.

  This coating solution was applied onto the charge generation layer by a dip coating method. Thereafter, an electron beam was irradiated in nitrogen under conditions of an acceleration voltage of 150 kV and a dose of 0.5 kGy. Subsequently, a heat treatment was performed for 90 seconds under the condition that the temperature of the photoconductor was 120 ° C. The oxygen concentration at this time was 10 ppm. Further, the photosensitive member was heat-treated in a hot air dryer adjusted to 100 ° C. in the atmosphere for 20 minutes to form a curable surface layer having a thickness of 10 μm.

  The value of Wo% measured from the surface of the photoreceptor was measured in the same manner as in Example 1. The roughening treatment of the outermost surface layer was performed by the same dry blast treatment as in Example 1.

  The prepared photoreceptor was mounted on the same electrophotographic apparatus as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Comparative Example 6]
In the production of the photoreceptor of Example 1, up to the second charge transport layer was produced in the same manner as in Example 1. Next, a roughening treatment was performed in the same manner as in Example 1.

  The prepared photosensitive member mounted on a process cartridge modified so that the cylindrical center angle A is 60 degrees was mounted on the same electrophotographic apparatus as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Comparative Example 7]
In the production of the photoreceptor of Example 1, up to the second charge transport layer was produced in the same manner as in Example 1. Next, a roughening treatment was performed in the same manner as in Example 1.

  The prepared photosensitive member mounted on a process cartridge modified so that the cylindrical center angle A is −40 degrees was mounted on the same electrophotographic apparatus as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

The measurement chart schematic of microhardness measuring apparatus Fischer scope H100V (made by H.Fischer). Schematic of a blasting device. 1 is a schematic view of an electrophotographic apparatus of the present invention. 1 is a schematic view of an electrophotographic apparatus having a process cartridge of the present invention.

Explanation of symbols

2-1 Nozzle 2-2 Nozzle fixing jig 2-3 Projecting air supply pipe 2-4 Blast abrasive supply pipe 2-5 Blast abrasive 2-6 Work fixing jig 2-7 Work (electrophotographic photosensitive member)
2-8 Nozzle support 2-9 Nozzle fixing arm 1 Image carrier (cylindrical photoconductor of the present invention)
1a shaft 2 charging means 3 developing means 3-1 developing sleeve 4 transfer means 5 cleaning means 6 pre-exposure means 7 transfer material 8 image fixing means L image exposure means T toner

Claims (6)

The tip position of the cleaning blade is such that the cylinder center angle A (the vertical direction of the cylinder center axis is 0 degree and the rotation direction of the cylindrical electrophotographic photosensitive member is positive) is within a range of −30 degrees to 50 degrees. The cylindrical electrophotographic photosensitive member, which is in contact with the cylindrical electrophotographic photosensitive member and installed so that the central axis of the cylinder is substantially horizontal, has a photosensitive layer, and is a Vickers square pyramid diamond indenter under an environment of 25 ° C. and a humidity of 50%. The universal hardness value (HU) pushed in at a maximum load of 6 mN is 150 N / mm ² or more and 220 N / mm ² or less, and the elastic deformation rate (Wo) is 44% or more and 65% or less. A charging step of charging an image carrier, a latent image forming step of forming an electrostatic latent image on the charging surface of the cylindrical electrophotographic photosensitive member, and a toner image carried on the toner carrier by transferring a toner image Form an image A development process, a transfer process in which a toner image formed on an image carrier is transferred to a transfer material with or without an intermediate transfer member, and an elastic member on the surface of the cylindrical electrophotographic photosensitive member In an image forming method having a cleaning step of removing the transfer residual toner remaining on the photosensitive member from the photosensitive member by bringing the cleaning blade into contact, the peripheral surface of the cylindrical electrophotographic photosensitive member has a dimple-shaped recess. An image forming method comprising a plurality of image forming methods. In a cylindrical electrophotographic photosensitive member having a cylindrical support and an organic photosensitive layer provided on the cylindrical support,
The peripheral surface of the cylindrical electrophotographic photosensitive member has a plurality of dimple-shaped recesses, and the ten-point average roughness Rzjis (A) measured by sweeping in the circumferential direction of the peripheral surface of the cylindrical electrophotographic photosensitive member is 0. The ten-point average roughness Rzjis (B) measured by sweeping in the direction of the generatrix of the peripheral surface of the cylindrical electrophotographic photosensitive member is 0.3 to 2.5 μm, and the cylinder The average interval RSm (C) of the unevenness measured by sweeping in the circumferential direction of the circumferential surface of the electrophotographic photosensitive member is 5 to 120 μm, and measured by sweeping in the direction of the generatrix of the circumferential surface of the cylindrical electrophotographic photosensitive member. The average interval RSm (D) of the irregularities is 5 to 120 μm, and the ratio value (D / C) of the average interval RSm (D) of the irregularities to the average interval RSm (C) of the irregularities is 0.5 to 1 5 is a cylindrical electrophotographic photosensitive member.   The maximum peak height Rp (F) of the peripheral surface of the cylindrical electrophotographic photosensitive member is 0.6 μm or less, and the maximum peak height of the maximum valley depth Rv (E) of the peripheral surface of the cylindrical electrophotographic photosensitive member. The cylindrical electrophotographic photosensitive member according to claim 1, wherein a ratio value (E / F) to Rp (F) is 1.2 or more. Among the dimple-shaped recesses, the number of the dimple-shaped recesses having a longest diameter in the range of 1 to 50 μm and a depth in the range of 0.1 to 2.5 μm is the number of the cylindrical electrophotographic photosensitive member. The cylindrical electrophotographic photosensitive member according to claim 1, wherein the number is 5 to 50 per 10,000 μm ^{2 of the} peripheral surface.   The total area of the dimple-shaped recesses having a longest diameter in the range of 1 to 50 μm and a depth in the range of 0.1 to 2.5 μm among the dimple-shaped recesses is the cylindrical electrophotographic photosensitive member. The cylindrical electrophotographic photosensitive member according to claim 1, wherein the cylindrical electrophotographic photosensitive member is 3 to 60% with respect to the area of the entire peripheral surface.   Among the dimple-shaped recesses, the average aspect ratio of the dimple-shaped recesses having the longest diameter in the range of 1 to 50 μm and the depth in the range of 0.1 to 2.5 μm is 0.50 to 0.00. 95. The cylindrical electrophotographic photosensitive member according to any one of claims 1 to 5.