Surface processing method, method for producing surface-processed article, kit for surface processing, and method for producing electrophotographic photoreceptor

Abstract

To provide a surface processing method that can process a target surface of high hardness while preventing abrasive grains or the like from remaining on the target surface.SOLUTION: A surface processing method for a surface including a target surface 101-s as a metal surface, comprises a step of spraying abrasive grains 105 onto a second surface 103-s2 of a resin film 103, the second surface 103-s2 being opposite to a first surface of the resin film 103 that is disposed in contact with the target surface 101-s and faces the target surface 101-s, thereby imparting an impact force to the resin film 103, and transmitting the impact force to the target surface 101-s via the resin film 103 to process the target surface 101-s covered with the resin film 103, wherein the resin film 103 has a thickness of 4.0-13.0 μm, contains at least one resin selected from the group consisting of polyethylene terephthalate, polyimide, and polyvinylidene chloride, and the abrasive grains 105 are spherical particles having an average particle diameter equal to or greater than the thickness of the resin film 103.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a surface processing method for forming an uneven shape on the surface of a workpiece, a method for manufacturing a surface processed product having unevenness on the surface, a surface processing kit, and a method for manufacturing an electrophotographic photoreceptor.

Background Art

[0002] As one of the methods for roughening the surface of various members, there is abrasive blasting. Patent Document 1 discloses a method for manufacturing a surface processing film including a roughening treatment step of forming a fine uneven surface on the surface by abrasive blasting. Further, Patent Document 2 discloses using abrasive grinding for forming a partition pattern on a glass plate constituting a gas discharge panel.

[0003] In abrasive blasting, there may be adhesion or penetration of abrasive grains or fine powders of abrasive grains onto the surface of the workpiece. Abrasive grains and their fine powders remaining on the surface of the blasted member may interfere with subsequent processing steps of the member. Specifically, for example, in a photoreceptor used in an electrophotographic image forming apparatus, the surface of a substrate containing aluminum may be roughened by abrasive blasting for suppressing interference fringes due to scattering of laser light for forming an electrostatic latent image, improving surface defects of the substrate, etc. At this time, when an organic photosensitive layer is formed on the blasted surface of the substrate with abrasive grains and their fine powders remaining thereon, the electrophotographic photoreceptor obtained may cause defects such as black spots and white spots in the electrophotographic image. Therefore, it is desirable that no abrasive grains or their fine powders exist on the blasted surface.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] At least one aspect of the present disclosure is directed to providing a surface treatment method capable of machining a machined surface having high hardness while preventing residues such as abrasive grains on the machined surface. At least one aspect of the present disclosure is directed to providing a method for manufacturing a surface-treated product having a high-hardness surface without leaving abrasive grains or the like on the surface. Also, at least one aspect of the present disclosure is directed to providing a surface machining treatment kit that does not leave abrasive grains or the like on a high-hardness machined surface. Furthermore, at least one aspect of the present disclosure is directed to providing a method for manufacturing an electrophotographic photoreceptor that contributes to the formation of high-quality electrophotographic images.

Means for Solving the Problems

[0006] According to at least one aspect of the present disclosure, there is provided a surface machining method for a surface including a metal surface as a machined surface, the surface machining method comprising: spraying abrasive grains onto a second surface of a resin film disposed in contact with the machined surface and opposite to a first surface facing the machined surface, to apply an impact force to the resin film; and transmitting the impact force to the machined surface through the resin film to machine the machined surface covered with the resin film, wherein the resin film has a thickness of 4.0 to 13.0 μm and contains at least one resin selected from the group consisting of polyethylene terephthalate, polyimide, polyvinylidene chloride, polyetheretherketone, and high-density polyethylene, and the abrasive grains are spherical particles having a number average particle diameter equal to or greater than the thickness of the resin film. A surface machining method is provided. According to at least one aspect of the present disclosure, there is provided a method for manufacturing a surface-treated article, comprising: step (i) of preparing an article having a metal surface; and step (ii) of subjecting the metal surface to surface treatment to obtain a surface-treated article having the processed metal surface, wherein step (ii) includes a step of processing the metal surface by the above-described surface treatment method. Also, according to at least one aspect of the present disclosure, there is provided a surface treatment kit for use in the above-described surface treatment method, comprising a resin film and abrasive grains, wherein the resin film has a thickness of 4.0 to 13.0 μm and contains at least one resin selected from the group consisting of polyethylene terephthalate, polyimide, polyvinylidene chloride, polyether ether ketone, and high-density polyethylene, and the abrasive grains are spherical particles having a number average particle diameter equal to or greater than the thickness of the resin film. A surface treatment kit is provided. Also, according to at least one aspect of the present disclosure, there is provided a method for manufacturing an electrophotographic photoreceptor, the electrophotographic photoreceptor having at least a substrate having a metal surface and an organic photosensitive layer on the metal surface, the manufacturing method comprising: step (i) of roughening the metal surface; and step (ii) of forming the organic photosensitive layer on the surface roughened in step (i), wherein step (i) includes a step of processing the metal surface by the surface treatment method according to any one of claims 1 to 8.

Advantages of the Invention

[0007] According to at least one aspect of the present disclosure, it is possible to obtain a surface treatment method capable of processing a work surface having high hardness while preventing the remaining of abrasive grains or the like on the work surface. According to at least one aspect of the present disclosure, it is possible to obtain a method for manufacturing a surface-treated article having a high-hardness surface without leaving abrasive grains or the like on the surface. Also, according to at least one aspect of the present disclosure, it is possible to obtain a surface treatment kit that does not leave abrasive grains or the like on a high-hardness work surface. Further, according to at least one aspect of the present disclosure, it is possible to obtain a method for manufacturing an electrophotographic photoreceptor that contributes to the formation of high-quality electrophotographic images.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0009] In this specification, the description of "XX or more and YY or less" or "XX to YY" representing a numerical range means a numerical range including the lower limit and the upper limit which are the endpoints, unless otherwise specified. Also, when the numerical ranges are described stepwise, the upper limit and the lower limit of each numerical range can be arbitrarily combined. In the present disclosure, for example, the description such as "at least one selected from the group consisting of XX, YY, and ZZ" means any one of XX, YY, ZZ, a combination of XX and YY, a combination of XX and ZZ, a combination of YY and ZZ, or a combination of XX, YY, and ZZ.

[0010] Patent Document 1 discloses that the impact force of abrasive grains sprayed on a protective layer is transmitted to a film through the protective layer to form an uneven shape on the surface of the film. In this way, it is considered that by spraying abrasive grains on the surface to be processed through the protective layer to process the surface to be processed and then removing the protective layer after processing, it is possible to prevent the remaining of abrasive grains and their fine powders on the surface to be processed. Hereinafter, in some cases, abrasive grains and their fine powders may be described as "abrasive grains etc.".

[0011] According to the study by the present inventors, when the surface to be processed is made of a material with low hardness such as resin and is easily blast-processed, in some cases, the surface to be processed can be roughened to a desired roughness by spraying abrasive grains through a protective layer.

[0012] However, for a metal member having a relatively high-hardness surface, such as those used for the substrate of an electrophotographic photoreceptor, for example, a substrate made of aluminum or an aluminum alloy, it has been difficult to perform surface processing by spraying abrasive grains through a resin protective layer as described in Patent Document 2. That is, in order to blast the surface of a substrate containing metal, it is necessary to spray relatively high-hardness abrasive grains at high pressure. At this time, the protective layer on the surface to be processed wears out early due to the collision of the abrasive grains, and at least a part of the protective layer is lost from the surface to be processed and at least a part of the surface to be processed is exposed before the surface to be processed is processed to the desired roughness. As a result, the abrasive grains may directly collide with the exposed surface to be processed, and the abrasive grains or the like may adhere to the surface to be processed. On the other hand, when the protective layer is thickened to prevent the disappearance of the protective layer, it has been difficult to sufficiently roughen the surface to be processed because the protective layer absorbs the impact caused by the collision of the abrasive grains.

[0013] Note that Patent Document 2 discloses using fine particles obtained by solidifying a liquid or a gas by cryogenic treatment (for example, ice particles, dry ice particles) to address the problem that the abrasive particles themselves for blast grinding become dust and have an adverse effect on the yield in other processes. However, ice particles and dry ice particles are not sufficient in terms of hardness and mass to roughen the surface of a metal member as described above, and it has been difficult to perform the desired surface processing.

[0014] Therefore, as a result of intensive studies by the present inventors, it has been found that even for a member having a hard surface to be processed and containing metal, by optimizing the physical properties of the resin film covering the surface to be processed, the physical properties of the abrasive grains, the processing conditions, etc., it is possible to perform the desired surface processing through the resin film. That is, a surface processing method according to an aspect of the present disclosure is a surface processing method of a surface including a metal surface as a surface to be processed. On the surface to be processed, abrasive grains are injected onto a second surface of a resin film disposed in contact with the surface to be processed, which is opposite to a first surface facing the surface to be processed, to apply an impact force to the resin film, and the impact force is transmitted to the surface to be processed through the resin film to process the surface to be processed covered with the resin film. The resin film has a thickness of 4.0 to 13.0 μm and contains at least one resin selected from the group consisting of polyethylene terephthalate, polyphenylene imide, polyvinylidene chloride, polyether ether ketone, and high-density polyethylene. Further, the abrasive grains are spherical particles having a number average particle diameter equal to or greater than the thickness of the resin film.

[0015] Further, a method for manufacturing a surface-treated product according to an aspect of the present disclosure includes a step (i) of preparing an article having a metal surface, and a step (ii) of surface-processing the metal surface as a surface to be processed to obtain a surface-processed product having the processed metal surface, and the step (ii) includes a step of processing the metal surface by the above surface processing method.

[0016] Hereinafter, an aspect of the surface processing method and the method for manufacturing a surface-processed product according to the present disclosure (hereinafter also referred to as "surface processing method, etc.") will be described in detail.

[0017] [Surface roughening method by blasting] A surface processing method, etc. according to an aspect of the present disclosure, with a metal surface as a surface to be processed, will be described with reference to FIG. 1. First, as shown in FIGS. 1A and 1B, a surface to be processed 101-s of a workpiece 101 is covered with a resin film 103 (film) having a thickness of 4.0 to 13.0 μm. The method of covering the surface to be processed 101-s with the resin film 103 is not particularly limited. For example, a resin film having a thickness of 4.0 to 13.0 μm, which has been previously formed into a sheet shape, may be placed in close contact with the surface to be processed 101-s, or a resin solution in which the resin is dissolved in a solvent may be applied onto the surface to be processed 101-s. A resin film having a thickness of 4.0 to 13.0 μm may be formed by spreading and drying. Alternatively, a film of a resin precursor solution containing at least one selected from the group consisting of monomers, oligomers, and prepolymers of the resin constituting the resin film is formed on the work surface 101-s, and the resin film may be formed on the work surface 101-s with a thickness of 4.0 to 13.0 μm by curing the film of the resin precursor solution. Here, the resin film 103 contains at least one resin selected from the group consisting of polyethylene terephthalate, polyimide, polyvinylidene chloride, polyether ether ketone, and high-density polyethylene. Next, abrasive grains 105 are sprayed from the nozzle 201 arranged at a predetermined interval on the second surface 103-s2 opposite to the first surface of the resin film 103 facing the workpiece 101 in the direction of arrow A1 toward the second surface 103-s2 of the resin film 103. The nozzle 201 stores abrasive grains and is connected to an abrasive grain supply unit 205 that supplies abrasive grains to the nozzle and a compressed gas supply unit (pump) 203 that supplies compressed base (e.g., air, etc.) to the nozzle. As a result, the abrasive grains 105 are sprayed from the nozzle 201 in a state of being mixed with high-pressure gas. Then, the impact force applied to the resin film 103 by the sprayed abrasive grains 105 is transmitted to the work surface 103-s2 to process (roughen) the work surface 103-s2. Here, for example, no When the nozzle 201 is reciprocated in the directions of arrow A201 and arrow A202, and the workpiece 101 is reciprocated in the direction of arrow 203 which is perpendicular to the directions of arrow A201 and A202, any part of the work surface can be processed. Alternatively, the nozzle 201 can be fixed and the workpiece 101 can be moved in the direction of arrow A204 which is perpendicular to the directions of arrow A203 and arrow A203 to also process any part of the work surface. Furthermore, by fixing the workpiece 101 and moving the nozzle 201 in the directions of arrow A201 and A202 and in a direction (not shown) perpendicular to the directions of arrow A201 and A202, any part of the work surface can also be processed.

[0018] After machining the desired portion of the surface to be machined 101-s in this manner, by removing the resin film 103 from the surface of the surface to be machined 101-s, a surface-machined product 101-t with the surface of the surface to be machined 101-s surface-machined (roughened) is manufactured (Fig. 2B).

[0019] As described above, in the case of abrasive blasting, when the surface to be machined of the workpiece is covered with a resin film containing at least one resin selected from the group consisting of polyethylene terephthalate, polyimide, polyvinylidene chloride, polyether ether ketone, and high-density polyethylene and is in the range of 4.0 to 13.0 μm in thickness, by performing abrasive blasting using spherical abrasive grains having a number average particle diameter equal to or greater than the thickness of the resin film, without causing significant damage to the resin film, the impact force applied to the resin film is transmitted to the surface to be machined through the resin film, and the surface to be machined can be machined. Therefore, after abrasive blasting, by removing the resin film, a surface-machined product without residues such as abrasive grains on the machined surface can be obtained.

[0020] Next, another aspect of the surface machining method and the like according to the present disclosure will be described with reference to Fig. 3. For members identical to those in Fig. 2, the same reference numerals may be given in Fig. 3 and the description may be omitted in some cases.

[0021] The aspect described with reference to Fig. 3 is different from the aspect described with reference to Fig. 2 in that the workpiece 101 has a cylindrical shape. When performing surface machining on the surface to be machined of the workpiece 101 having a cylindrical shape, for example, as shown in Fig. 3, the resin film 103 is wound and fixed so as to be in close contact with the surface to be machined of the workpiece 101.

[0022] In this aspect, although the resin film 103 is provided so as to cover the entire circumferential surface of the cylindrical workpiece and then subjected to abrasive blasting, it is not limited thereto. For example, as shown in Fig. 4, a sheet-like resin film 103 is driven in accordance with the rotation of the workpiece 101 and is at least on the surface to be machined 101-s. At least in part, the resin film 103 is brought into contact, and the surface of the work surface 101-s can also be processed through the resin film 103 by spraying abrasive grains 105 from the nozzle 201 toward the second surface 103-s2 of the resin film 103 corresponding to the contact portion between the sheet-like resin film and the work surface 101-s.

[0023] The inventors of the present invention conducted the following experiments in order to optimize various conditions for blasting a work surface, which is a metal surface, through a resin film. That is, the control factors for blasting a work surface containing metal through a resin film include the items listed in Table 1.

[0024]

Table 1

[0025] <Experiment A1> As a workpiece, an aluminum plate with a purity of 99% (length: 50 mm, width: 50 mm, thickness: 0.5 mm, mirror finish) was prepared. The Vickers hardness (HV) measured on the work surface (mirror surface) of this aluminum plate, measured based on Japanese Industrial Standard (JIS) Z 2244:2020, was about 30, and the ten-point average roughness (hereinafter also referred to as "RzJIS") based on JIS B0601:2013 was about 0.2 μm. Note that RzJIS was measured under the conditions of a measurement length of 4 mm, a tip radius (R) of the stylus used for measurement of 2 μm, a stylus feed speed of 0.1 mm / second, and a cut-off value λc of 0.8 mm.

[0026] A film of polyethylene terephthalate (PET) with a thickness of 6.5 μm (product name: Lumirror; manufactured by Toray Industries, Inc.) was adhered to the surface of the above aluminum plate as a resin film. Next, spherical zirconia particles with a number average particle diameter of 100 μm (product name: TRESERAM zirconia beads; manufactured by Toray Industries, Inc.) were sprayed onto the second surface of the resin film on the side opposite to the first surface facing the aluminum plate. The control factors 4-1 to 4-3 of the processing conditions were fixed under the conditions shown in Table 2. Note that a nozzle with a diameter of 3 mm was used to eject the abrasive grains.

[0027]

Table 2

[0028] Then, the state of the resin film on the work surface and the processing state of the work surface after the blasting process were confirmed. Regarding the state of the resin film, it was observed with an optical microscope (50 - 500 times magnification) to confirm the presence or absence of exposure of the work surface. Also, regarding the processing state of the work surface, the resin film was removed from the work surface, and the ten-point average roughness (RzJIS) was measured. Furthermore, in the observation of the state of the resin film when exposure of the work surface was observed, the presence or absence of residue such as abrasive grains on the work surface was observed with an optical microscope (50 - 500 times magnification). The results are also shown in Table 3.

[0029] <Experiment B1 - B11> As the workpiece, a cylindrical aluminum alloy cylinder with an outer diameter of 30.5 mm, an inner diameter of 28.5 mm, and a length in the width direction perpendicular to the circumferential direction of 370 mm was prepared. The aluminum alloy used was the aluminum alloy defined as alloy number A3003 (symbol A3003P) in Japanese Industrial Standard (JIS) H4000:2022 Aluminum and Aluminum Alloy Sheets and Bars. The Vickers hardness (HV) measured on the work surface (mirror surface) of this cylinder, based on Japanese Industrial Standard (JIS) Z 2244:2020, was about 40. Also, this cylinder was degreased and washed after cutting, and the outer peripheral surface, which was the work surface, had a mirror finish, and RzJIS was 0.1 μm or less. A resin film made of various resin materials shown in Table 3 was wound around and fixed to the outer peripheral surface of this cylindrical body. Subsequently, as shown in Fig. 3, while rotating this cylindrical body, various abrasive grains shown in Table 3 were ejected from nozzles arranged around it to perform blasting. As for the blasting conditions, it was the same as in Experiment A1 except that the processing time of the surface to be processed was set to 64 seconds. Then, the state of the resin film on the surface to be processed and the processing state of the surface to be processed after the blasting were confirmed in the same manner as in Experiment A1. The results are shown together in Table 3.

[0030]

Table 3

[0031] Details of the resin film and abrasive grains described in Table 3 are shown in Table 4.

[0032]

Table 4

[0033] Note that the Rockwell hardness of the resin film is the value of the hardness symbol "HRR" measured using a steel ball with a diameter of 12.7 mm as the indenter in an environment with a temperature of 25°C on a test piece separately made of the same resin as the resin constituting the resin film, based on Japanese Industrial Standard (JIS) Z2245:2021. The thickness of the test piece was adjusted according to the provisions of Annex B of JIS Z2245:2021. The thickness of the resin film is the value measured with a film thickness measuring instrument.

[0034] The number average particle diameter of the abrasive grains is the value obtained by sampling a part of the abrasive grains used in the blasting and determining the average value of the equivalent circle diameter of the projected image of the taken-out abrasive grain sample by microscopic observation and image analysis. The circularity is the average value of the circularity obtained from the following calculation formula (1) with the perimeter of the projected image of one abrasive grain as the denominator and the perimeter of a circle having the same area as the area of the projected image as the denominator. In the present disclosure, when the circularity is 0.9 or more, it is defined as spherical, and when it is less than 0.9, it is defined as polygonal.

[0035] In Table 3, the state of the resin film was evaluated according to the following criteria. Rank A: The degree of wear due to the impact of abrasive grains on the second surface of the resin film was slight, and no exposure of the machined surface was observed. Rank A': No exposure of the machined surface due to the impact of abrasive grains on the second surface of the resin film was observed. Elongation occurred in the resin film, and striped gaps were seen between the cylindrical body and the resin film. Rank B: The resin film had perforations or tears due to the impact of abrasive grains on the second surface.

[0036] Also, the processing force rank in Table 3 is a rank evaluated according to the following criteria based on the state of the surface (RzJIS or adhesion of abrasive grains, etc.) of the surface processed by resin film blasting. Rank A: RzJIS was 1 μm or more. Rank B: RzJIS was 0.5 μm or more and less than 1 μm. Rank C: RzJIS was less than 0.5 μm and had a metallic luster.

[0037] From Table 3, it can be seen that when polyvinylidene chloride, polyimide, PET, or PEEK with a Rockwell hardness in the range of 50 - 126 is used as the resin material and Al2O3 or ZrO2 is used as the abrasive grains, the machined surface can be processed without causing significant damage to the resin film. When Al2O3 is used as the abrasive grains and a polyimide film with a thickness of 12.5 μm or a PET film with a thickness of 12.0 μm is used as the resin film, the processing force rank becomes Rank B. This is considered to be because the resin film was relatively thick, weakening the transmission of the impact force of the abrasive grains to the machined surface. Therefore, when using Al2O3 as the abrasive grains, it can be seen that by using a resin film with a Rockwell hardness in the range of 50 - 126 and a thickness of 4.5 - 7.5 μm as the resin film, it is possible to sufficiently roughen the machined surface while suppressing damage to the resin film. In addition, when high-density polyethylene is used as the resin material, it is possible to roughen the surface without the adhesion of abrasive grains. However, since a striped gap is generated between the cylindrical body and the resin film, resulting in non-uniform processing, it is necessary to manage the processing time and perform the movement and replacement of the resin film.

[0038] When ZrO2 is used as the abrasive grain, even when a polyimide film with a thickness of 12.5 μm or a PET film with a thickness of 12.0 μm is used as the resin film, the processing force rank is Rank A. The reason is considered to be that since ZrO2 has a higher density than Al2O3 and the impact momentum of the abrasive grain is relatively large, the impact force of the abrasive grain can be more effectively transmitted to the work surface through the resin film. Here, the damage to the resin film was almost negligible even when high-density ZrO2 was used as the abrasive grain, similar to the case when Al2O3 was used as the abrasive grain.

[0039] On the other hand, when polygonal SiC is used as the abrasive grain, even when polyimide or PET with a Rockwell hardness of 120 - 126 is used for the resin film, damage occurred to the resin film by the blasting process (Rank B). This is considered to be due to the polygonal shape of the abrasive grain, resulting in wear and the like due to the impact of the abrasive grain even on a relatively high-hardness resin film. Also, when SiC with a polygonal shape and an average particle size of 25 μm was used, the processing of the work surface was relatively insufficient compared to the case when SiC with an average particle size of 57 μm was used. This is considered to be because the number-average particle size of the abrasive grain is small, resulting in a relatively small impact momentum of the abrasive grain, so that the impact force of the abrasive grain could not be sufficiently transmitted to the work surface.

[0040] Based on the above experimental results, the preferred embodiments in the surface processing method and the like according to one aspect of the present disclosure will be described.

[0041] <Workpiece> A surface finishing method according to one aspect of the present disclosure is premised on a metal surface being a surface to be processed. Specifically, for example, it relates to a method for processing a surface to be processed such that the Vickers hardness measured on the surface to be processed is 20 or more and 50 or less, particularly 30 or more and 40 or less. The Vickers hardness is measured in accordance with Japanese Industrial Standard (JIS) Z 2244:2020. At this time, the measurement temperature is 23°C ± 5°C, and the test force is set according to the hardness in accordance with the provisions of the above standard. The holding time is also set to 10 to 15 seconds as specified in the above standard. In the case where the object to be processed is a substrate of an electrophotographic photoreceptor having a cylindrical shape described later, it is preferable to apply the hardness correction coefficient specified in Appendix B.2 of the above standard when calculating the Vickers hardness.

[0042] <Resin film> The resin film disposed on the surface to be processed has a thickness in the range of 4.0 to 13.0 μm and contains at least one resin selected from the group consisting of polyethylene terephthalate, polyimide, polyvinylidene chloride, polyether ether ketone, and high-density polyethylene from the viewpoint of preventing the exposure of the surface to be processed due to damage caused by the collision of abrasive grains and reliably transmitting the impact force of the abrasive grains to the surface to be processed. The thickness of the resin film is preferably in the range of 4.5 to 12.0 μm, particularly preferably in the range of 6.0 to 8.0 μm. Also, as for the hardness of the resin film, from the viewpoint of preventing the exposure of the surface to be processed due to damage caused by the collision of abrasive grains and reliably transmitting the impact force of the abrasive grains to the surface to be processed, the Rockwell hardness is preferably 50 to 150, particularly preferably 100 to 130, and more preferably 120 to 130.

[0043] <Abrasive grains> The abrasive grains used have a number average particle diameter equal to or greater than the thickness of the resin film and are spherical. Here, the spherical shape specifically means that the circularity represented by the following calculation formula (1), with the perimeter of the projected image of the abrasive grain as the denominator and the perimeter of the circle having the same projected area as the projected image of the abrasive grain as the numerator, is 0.900 or more. Circularity = (Perimeter of a circle having the same projected area as the projected image of the abrasive grain) / (Perimeter of the projected image of the abrasive grain) (1) The circularity obtained by the above calculation formula (1) is a value of 1.0 or less, and a circularity of 1.0 means a perfect circle. The circularity can be obtained, for example, by observing the shape of the abrasive grains using a microscope and image analysis. Usually, since innumerable abrasive grains are used in abrasive blasting, it is difficult to calculate the circularity for all the abrasive grains. Therefore, a part of the abrasive grains used in abrasive blasting is sampled, and the average value of the circularity of the abrasive grains is calculated by analyzing the taken sample using the above flow-type particle image analyzer or the like. This average value is taken as the circularity of the abrasive grains. The abrasive grains are spherical, and the new Mohs hardness (corrected Mohs hardness) is preferably 10 to 14, particularly preferably 11 to 13, and the density is preferably 3.0 to 7.0, particularly preferably 3.5 to 6.5, and more preferably 5.5 to 6.5. Such abrasive grains include, for example, alumina (Al2O3) and zirconium oxide (ZrO2).

[0044] Also, from the viewpoint of surely transmitting the impact force of the abrasive grains to the work surface through the resin film, the number average particle diameter of the abrasive grains is equal to or greater than the thickness of the resin film as described above. As described above, since the thickness of the resin film is 4.0 to 13.0 μm, the average particle diameter of the abrasive grains is preferably 4.0 μm or more, particularly preferably 40.0 μm or more and 110 μm or less, and more preferably 45.0 μm or more and 105 μm or less. The particle diameter of the abrasive grains is the diameter of a circle having the same projected area as the projected image of the abrasive grains, that is, the equivalent circle diameter. Also, similar to the circularity, it is difficult to obtain the equivalent circle diameters of all the abrasive grains used in abrasive blasting. Therefore, a part of the abrasive grains used in abrasive blasting is sampled, and the average value of the equivalent circle diameters of the taken sample abrasive grains is calculated. This average value is taken as the number average particle diameter of the abrasive grains.

[0045] <Processing Conditions> 4-1: Injection Pressure The pressure of the gas when spraying onto the second surface of the resin film from the nozzle is not particularly limited, and can be appropriately set within a range where no perforation or breakage occurs in the resin film, according to the degree of processing of the surface to be processed, the material of the resin film, and the thickness of the resin film. The pressure can be set, for example, within the range of 0.1 to 0.5 MPa. 4-2: Processing time of the second surface The processing time of the second surface of the resin film is not particularly limited, and can be appropriately set within a range where no perforation or breakage occurs in the resin film, according to the degree of processing of the surface to be processed, the material of the resin film, and the thickness of the resin film. 4-3: Distance between the second surface of the resin film and the nozzle tip, and the angle formed by the second surface of the resin film and the flow of abrasive grains from the nozzle The distance between the second surface of the resin film and the nozzle tip is not particularly limited, and can be appropriately set within a range where no perforation or breakage occurs in the resin film, according to the degree of processing of the surface to be processed, the material of the resin film, and the thickness of the resin film. The angle formed by the second surface of the resin film and the flow of abrasive grains from the nozzle is also not particularly limited, and can be appropriately set within a range where no perforation or breakage occurs in the resin film, according to the degree of processing of the surface to be processed, the material of the resin film, and the thickness of the resin film.

[0046] [Method for manufacturing an electrophotographic photoreceptor] The surface processing method and the like according to one aspect of the present disclosure are extremely effective, for example, in roughening the surface of the support of an electrophotographic photoreceptor. As described above, in an electrophotographic photoreceptor used in an electrophotographic image forming apparatus, for example, for the surface (hereinafter, also simply referred to as "surface") on the side facing the organic photosensitive layer of a substrate having a metal surface containing a metal such as aluminum, in order to suppress interference fringes caused by scattering of laser light for forming an electrostatic latent image, or to improve surface defects of the substrate, it may be roughened by blasting. At this time, an electrophotographic photoreceptor obtained by forming an organic photosensitive layer on a processed surface with abrasive grains or their fine powder remaining may cause defects such as black spots and white spots in the electrophotographic image. Here, by applying the surface processing method according to one aspect of the present disclosure to roughen the surface of the substrate of the electrophotographic photoreceptor, adhesion of abrasive grains and the like to the surface can be prevented, and an electrophotographic photoreceptor that contributes to the formation of a high-quality electrophotographic image can be manufactured. The method for manufacturing an electrophotographic photoreceptor according to one aspect of the present disclosure is directed to a method for manufacturing an electrophotographic photoreceptor having at least a substrate having a metal surface and an organic photosensitive layer on the metal surface. And the manufacturing method includes: (i) a step of roughening the metal surface of the substrate; and (ii) a step of forming the organic photosensitive layer on the surface roughened in the step (i), and the step (i) includes a step of roughening the metal surface of the substrate as a surface to be processed by the above-described surface processing method.

[0047] Specifically, abrasive grains are sprayed onto the second surface of the resin film disposed in contact with the metal surface, which is opposite to the first surface facing the metal surface, to apply an impact force to the resin film, and the impact force is transmitted to the metal surface through the resin film to roughen the metal surface covered with the resin film.

[0048] All of the specific aspects such as the surface processing method for roughening the metal surface of the substrate of the electrophotographic photoreceptor are incorporated herein by reference to the description of the above-described surface processing method and the like.

[0049] In particular, when the electrophotographic photoreceptor is a cylindrical electrophotographic photoreceptor (electrophotographic photosensitive drum), the surface processing method of the cylindrical substrate specifically described with reference to FIG. 3 or FIG. 4 can be preferably used.

[0050] Examples of the metal used for the substrate of the electrophotographic photoreceptor include aluminum, iron, nickel, stainless steel, and the like. Among them, aluminum and alloys containing aluminum are preferably used.

[0051] Furthermore, in order to suppress density unevenness caused by interference fringes of image exposure light in the electrophotographic photoreceptor, a method of roughening the substrate surface is known. As the degree of roughening of the metal surface of the substrate, the RzJIS of the metal surface is preferably 0.3 to 5.0 μm, and particularly preferably 0.5 to 3 .0 μm.

[0052] On the substrate whose metal surface has been roughened by the above surface treatment method, an organic photosensitive layer is formed, for example, on the metal surface. The organic photosensitive layer contains at least a charge generating substance and a charge transporting substance. As the structure of the organic photosensitive layer, for example, there are a laminated type and a single-layer type. The laminated organic photosensitive layer includes a laminate of a charge generation layer containing a charge generating substance and a charge transport layer containing a charge transporting substance. On the other hand, the single-layer organic photosensitive layer has a single-layer organic photosensitive layer in which a charge generating substance and a charge transporting substance coexist. Each of the above layers constituting the organic photosensitive layer may contain a binder resin and other additives in addition to the above materials. Further, the organic photosensitive layer may be provided in contact with the roughened metal surface of the substrate, or may be provided via another layer. Examples of the other layer include an undercoat layer for improving the adhesion of the organic photosensitive layer to the substrate and for preventing charge injection into the substrate. Further, a protective layer may be provided on the surface on the side opposite to the side facing the substrate of the organic photosensitive layer in order to improve the durability of the electrophotographic photoreceptor.

[0053] <Charge generation layer> The charge generation layer preferably contains a charge generating substance and a resin. Examples of the charge generating substance include azo pigments, perylene pigments, polycyclic quinone pigments, indigo pigments, phthalocyanine pigments, etc. Among these, azo pigments and phthalocyanine pigments are preferred. Among the phthalocyanine pigments, oxytitanium phthalocyanine pigments, chlorogallium phthalocyanine pigments, and hydroxygallium phthalocyanine pigments are preferred. The content of the charge generating substance in the charge generation layer is preferably 40% by mass or more and 85% by mass or less, more preferably 60% by mass or more and 80% by mass or less, based on the total mass of the charge generation layer. Examples of the resin for the charge generation layer include polyester resins, polycarbonate resins, polyvinyl acetal resins, polyvinyl butyral resins, acrylic resins, silicone resins, epoxy resins, melamine resins, polyurethane resins, phenol resins, polyvinyl alcohol resins, cellulose resins, polystyrene resins, polyvinyl acetate resins, polyvinyl chloride resins, etc. Among these, polyvinyl butyral resin is more preferred. Further, the charge generation layer may further contain additives such as antioxidants and ultraviolet absorbers. Specifically, examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, and the like. The average film thickness of the charge generation layer is preferably 0.1 μm or more and 1 μm or less, and more preferably 0.15 μm or more and 0.4 μm or less.

[0054] The charge generation layer can be formed by preparing a coating solution for the charge generation layer containing the above-mentioned respective materials and a solvent, forming this coating film, and drying it. Examples of the solvent used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, aromatic hydrocarbon-based solvents, and the like.

[0055] <Charge transport layer> The charge transport layer preferably contains a charge transport material and a resin. Examples of the charge transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these substances. Among these, triarylamine compounds and benzidine compounds are preferred. The content of the charge transport material in the charge transport layer is preferably 25% by mass or more and 70% by mass or less, and more preferably 30% by mass or more and 55% by mass or less with respect to the total mass of the charge transport layer. Examples of the resin include polyester resins, polycarbonate resins, acrylic resins, polystyrene resins, and the like. Among these, polycarbonate resins and polyester resins are preferred. Among the polyester resins, polyarylate resins are particularly preferred. The content ratio (mass ratio) of the charge transport material to the resin is preferably 4:10 to 20:10, and more preferably 5:10 to 12:10.

[0056] In addition, the charge transport layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slip agents, and abrasion resistance improvers. Specifically, examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

[0057] The average film thickness of the charge transport layer is preferably 5 μm or more and 50 μm or less, more preferably 8 μm or more and 40 μm or less, and particularly preferably 10 μm or more and 30 μm or less.

[0058] The charge transport layer can be formed by preparing a coating solution for the charge transport layer containing the above-mentioned various materials and solvents, forming this coating film, and drying it. Examples of the solvent used in the coating solution include alcohol solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents. Among these solvents, ether solvents or aromatic hydrocarbon solvents are preferred.

[0059] <Undercoat layer> The undercoat layer preferably contains a resin. Further, the undercoat layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of the resin include polyester resins, polycarbonate resins, polyvinyl acetal resins, acrylic resins, epoxy resins, melamine resins, polyurethane resins, phenol resins, polyvinyl phenol resins, alkyd resins, polyvinyl alcohol resins, polyethylene oxide resins, polypropylene oxide resins, polyamide resins, polyamic acid resins, polyimide resins, polyamideimide resins, and cellulose resins. Examples of the polymerizable functional groups of the monomers having polymerizable functional groups include isocyanate groups, blocked isocyanate groups, methylol groups, alkylated methylol groups, epoxy groups, metal alkoxide groups, hydroxyl groups, amino groups, carboxyl groups, thiol groups, carboxylic anhydride groups, carbon-carbon double bond groups, and the like. Further, the undercoat layer may further contain an electron transport material, a metal oxide, a metal, a conductive polymer, etc. for the purpose of enhancing electrical properties. Among these, it is preferable to use an electron transport material and a metal oxide. Examples of the electron transport material include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadienylidene compounds, fluorenone compounds, xanthone compounds, benzophenone compounds, cyanovinyl compounds, halogenated aryl compounds, silole compounds, boron-containing compounds, etc. As the electron transport material, an electron transport material having a polymerizable functional group may be used and copolymerized with the above-described monomer having a polymerizable functional group to form an undercoat layer as a cured film. Examples of the metal oxide include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, silicon dioxide, etc. Examples of the metal include gold, silver, aluminum, etc. Further, the undercoat layer may further contain an additive. The average film thickness of the undercoat layer is preferably 0.1 μm or more and 50 μm or less, more preferably 0.2 μm or more and 40 μm or less, and particularly preferably 0.3 μm or more and 30 μm or less. The undercoat layer can be formed by preparing a coating solution for the undercoat layer containing the above-described respective materials and a solvent, forming this coating film, and drying and / or curing it. Solvents used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, aromatic hydrocarbon-based solvents, and the like.

[0060] <Protective layer> The protective layer preferably contains conductive particles and / or a charge transport material and a resin. Examples of the conductive particles include particles of metal oxides such as titanium oxide, zinc oxide, tin oxide, and indium oxide. Examples of the charge transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these substances. Among these, triarylamine compounds and benzidine compounds are preferred. Examples of the resin include polyester resins, acrylic resins, phenoxy resins, polycarbonate resins, polystyrene resins, phenolic resins, melamine resins, and epoxy resins. Among these, polycarbonate resins, polyester resins, and acrylic resins are preferred. Further, the protective layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of the reaction at that time include thermal polymerization reaction, photopolymerization reaction, and radiation polymerization reaction. Examples of the polymerizable functional group of the monomer having a polymerizable functional group include an acrylic group and a methacrylic group. As the monomer having a polymerizable functional group, a material having a charge transport ability may be used. The protective layer may contain additives such as an antioxidant, an ultraviolet absorber, a plasticizer, a leveling agent, a slipperiness imparting agent, and a wear resistance improving agent. Specifically, hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, boron nitride particles, etc. are mentioned. The average film thickness of the protective layer is preferably 0.5 μm or more and 10 μm or less, and more preferably 1 μm or more and 7 μm or less. The protective layer can be formed by preparing a coating solution for the protective layer containing each of the above materials and a solvent, forming this coating film, and drying and / or curing it. Examples of the solvent used in the coating solution include alcohol solvents, ketone solvents, ether solvents, sulfoxide solvents, ester solvents, and aromatic hydrocarbon solvents.

[0061] <Method for manufacturing an electrophotographic photoreceptor> As a method for forming each of the above layers on the roughened metal surface, for example, a method of preparing a coating solution for each of the above layers, applying the coating solution in a desired layer order, and drying it can be mentioned. At this time, examples of the coating method of the coating solution include dip coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, ring coating, and the like. Among these, dip coating is preferable from the viewpoints of efficiency and productivity. As a method for drying the coating film, for example, a method of drying and / or curing using hot air can be mentioned.

Examples

[0062] Examples and comparative examples are shown below to more specifically explain the surface processing method and the like according to the present disclosure. Note that the surface processing method and the like according to the present disclosure are not limited to the following specific embodiments.

[0063] [Example 1] As a workpiece, a mirror-finished aluminum plate (purity 99%) with a length of 50 mm, a width of 50 mm, and a thickness of 0.5 mm was prepared. The RzJIS of the mirror-finished surface of the aluminum plate was about 0. 2 μm. Also, the Vickers hardness measured on the surface of this aluminum plate was about 30. As the resin film, a polyethylene terephthalate (PET) film (product name: Lumirror; manufactured by Toray Industries, Inc.) with a thickness of 6.5 μm was prepared.

[0064] Next, as shown in Fig. 1B, the resin film was placed on one surface of the aluminum plate and fixed. Next, abrasive grains were sprayed onto the second surface of the resin film, which is opposite to the side facing the aluminum plate, to perform blasting (see Fig. 2A). As the abrasive grains, spherical zirconia particles (trade name: TRESERAM; manufactured by Toray Industries, Inc.) with a number average particle diameter of 100 μm were used. As the conditions for the blasting process, the pressure of the compressed air for ejecting the abrasive grains was 0.2 MPa, the diameter of the nozzle for ejecting the abrasive grains was 3 mm, and the distance between the tip of the nozzle and the second surface of the resin film was 110 mm. Also, the nozzle was arranged such that the flow of the abrasive grains ejected from the nozzle hit the second surface of the resin film at a substantially right angle. Further, the aluminum plate coated with the resin film was relatively moved with respect to the nozzle so that the total impact time of the abrasive grains on the second surface of the resin film was 12 seconds. Then, the resin film was removed from the aluminum plate to obtain a surface-treated product. As a result of visually observing the treated surface of the aluminum plate as the obtained surface-treated product, it was confirmed that the surface was silver-white and roughened. Also, as a result of observing the treated surface with an optical microscope (50 to 500 times magnification), no residue (adhesion or penetration) of abrasive grains or the like on the treated surface was observed. Further, the ten-point average roughness (RzJIS) of the treated surface was measured using a surface roughness measuring instrument (trade name: SE-3500, manufactured by KOSAKA Laboratory Ltd.) under the measurement conditions of a measurement length of 4 mm, a feed rate of 0.1 mm / sec, and a cut-off value λc of 0.8 mm. As a result, RzJIS was 3.6 μm. On the other hand, As a result of observing the second surface of the resin film after the blasting process with an optical microscope (50 to 500 times magnification), a small amount of abrasive grains were confirmed. However, no holes or tears due to the blasting process were observed in the resin film.

[0065] From the above results, it was found that the surface of the aluminum plate can be roughened without leaving abrasive grains or the like on the surface. Furthermore, by adjusting the pressure and treatment time when spraying the abrasive grains, the surface of the aluminum plate can have an RzJIS of 0.5 to 5.0 μm without causing perforations or tears in the resin film. It was possible to roughen within the range.

[0066] [Examples 2 to 7] As the workpiece, a cylindrical aluminum alloy cylinder with an outer diameter of 30.5 mm, an inner diameter of 28.5 mm, and a length in the width direction orthogonal to the circumferential direction of 370 mm was prepared. The aluminum alloy is the aluminum alloy specified as alloy number A3003 (symbol A3003P) in Japanese Industrial Standard (JIS) H4000:2022 Aluminum and Aluminum Alloy plates and bars. The Vickers hardness (HV) measured on the machined surface (mirror surface) of this cylinder, measured based on Japanese Industrial Standard (JIS) Z 2244:2020, was about 40. Also, this cylinder was degreased and washed after cutting, and the outer peripheral surface, which is the machined surface, has a mirror (metal) luster, and RzJIS is 0.1 μm or less was. A resin film was wound around and fixed to the outer peripheral surface of this cylinder. Subsequently, as shown in Fig. 3, while rotating this cylinder, abrasive grains were sprayed from the nozzles arranged around it to perform blasting. The resin films and abrasive grains used in Examples 2 to 7 are shown in Table 5. The blasting conditions were the same as those in Example 1 except that the processing time of the machined surface was set to 64 seconds. The blasted portions of the outer surfaces of the cylinders after blasting obtained in Examples 2 to 7 were silver-white, and it was confirmed that the outer surfaces were roughened. Also, as a result of observation with an optical microscope (50 to 500 times magnification), no residue (adhesion or penetration) of abrasive grains or the like on the treated surface was observed. Furthermore, the ten-point average roughness (RzJIS) of the blasted portion of the outer surface of the cylinder was measured using a surface roughness measuring instrument (product name: SE-3500, manufactured by Kosaka Laboratory Ltd.) under the measurement conditions of a measurement length of 4 m m, a feed rate of 0.1 mm / sec, and a cut-off value λc of 0.8 mm. The results are also shown in Table 6. In addition, as a result of observing the second surface of the resin film after the blasting process with an optical microscope (100 times magnification), a small amount of abrasive grains were confirmed. However, no holes or tears associated with the blasting process were observed in the resin film.

[0067] [Comparative Examples 1 - 5] The blasting process was carried out in the same manner as in Example 2, except that the resin film and the abrasive grains were as described in Table 5. The results are shown together in Table 6. Regarding Comparative Examples 1 - 3 that used polygonal abrasive grains as the abrasive grains, penetration of the abrasive grains into the resin film and the like were observed, and perforations were recognized in a part of the resin film. As a result, adhesion of the abrasive grains was observed on a part of the outer surface of the cylindrical body. In addition, in Comparative Examples 4 - 5 where the blasting process was carried out by directly spraying the abrasive grains onto the outer surface of the cylindrical body without using the resin film, although roughening of the outer surface of the cylindrical body was achieved, adhesion of abrasive grains and the like was observed over the entire treated surface. In particular, penetration of the abrasive grains was observed on the outer surface of the cylindrical body according to Comparative Example 5 where polygonal abrasive grains were directly sprayed onto the outer surface of the cylindrical body for the blasting process. The evaluation results of Examples 2 - 7 and Comparative Examples 1 - 5 are shown in Table 6.

[0068]

Table 5

[0069]

Table 6

[0070] [Example 8] An electrophotographic photoreceptor was manufactured using the cylindrical body obtained in Example 2, whose outer surface had an RzJIS of 3.1 μm and on which no abrasive grains or the like remained on the outer surface. <Manufacture of electrophotographic photoreceptor> ​A coating film of an intermediate layer paint obtained by dissolving the following components in a mixed solution of 400 parts of methanol and 200 parts of n-butanol was formed on the outer surface of the above-mentioned cylindrical body by the dip coating method. The cylindrical body on which the coating film was formed was placed in an oven and heated at a temperature of 100 °C for 30 minutes to form an undercoat layer with a film thickness of 0.7 μm. · Copolymerized nylon resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.): 10 parts, · Methoxymethylated 6 nylon resin (trade name: Trelene EF-30T, manufactured by Imperial Chemical Industries, Ltd.): 30 parts.

[0071] Next, the following materials were prepared. · Oxytitanium phthalocyanine pigment having strong peaks at 9.0 °, 14.2 °, 23.9 °, and 27.1 ° of Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction: 10 parts (charge generating substance), · Polyvinyl butyral (trade name: Esrec BX-1, manufactured by Sekisui Chemical Co., Ltd.): 6.7 parts, · Cyclohexanone: 350 parts. The above materials were put into a sand mill using 1 mm diameter glass beads and dispersed for 4 hours. Then, 300 parts of ethyl acetate was added to prepare a coating solution for the charge generation layer. A coating film of this coating solution for the charge generation layer was formed on the undercoat layer. The cylindrical body on which this coating film was formed was placed in an oven and heated at a temperature of 80 °C for 10 minutes to form a charge generation layer with a film thickness of 0.17 μm.

[0072] Next, the following materials were prepared. · Compound represented by the following structural formula (charge transporting substance): 70 parts JPEG2025109463000008.jpg30116 · Polycarbonate resin (trade name: Iupilon Z400, manufactured by Mitsubishi Engineering Plastics Corporation, bisphenol Z type polycarbonate): 100 parts. The above materials were dissolved in a mixed solvent of 600 parts of mixed xylene and 200 parts of dimethoxymethane to prepare a coating solution for the charge transport layer. A coating film of this coating solution for the charge transport layer was formed on the charge generation layer formed above by the dip coating method. The cylindrical body on which the coating film was formed was placed in an oven and heated at a temperature of 100 °C for 30 minutes to form a charge transport layer with a film thickness of 20 μm. Thus, an electrophotographic photoreceptor was produced.

[0073] <Evaluation of the electrophotographic photoreceptor> The obtained electrophotographic photoreceptor was mounted on the cyan station of a modified machine of a full-color electrophotographic image forming apparatus (trade name: imagePRESS C910, manufactured by Canon Inc.) as an evaluation apparatus, and evaluation was performed under the following conditions. Laser light with a wavelength of 670 nm was used for image exposure of this evaluation apparatus. This evaluation apparatus was installed in an environment of a temperature of 23 °C and a humidity of 50% RH. The surface potential of the electrophotographic photoreceptor was measured by removing the developing cartridge from the evaluation apparatus, fixing a potential probe (trade name: model 6000B-8, manufactured by Trek Inc.) thereto, and using a surface potentiometer (model 344: manufactured by Trek Inc.). First, the applied voltage to the charging member (charging roller) was adjusted so that the dark potential (VD) of the electrophotographic photoreceptor used for evaluation became -800 V. Next, the laser light amount was adjusted so that the bright potential (VL) became -300 V when image exposure was irradiated.

[0074] After adjusting VD and VL in this way, the potential probe was removed from the main body, the developing cartridge was mounted so that an image could be output, and then a cyan full-area halftone image was output onto A3-size paper. The obtained halftone image was visually observed, and the presence or absence of density unevenness (interference fringes), and if there was density unevenness, the degree thereof, as well as the presence or absence of black dots, and if there were black dots, the degree thereof were evaluated according to the following criteria. The results are shown in Table 7. 〔Density unevenness〕 Rank A: No occurrence of density unevenness Rank B: Slight density unevenness can be confirmed, but there is no problem in actual use Rank C: Clear unevenness in density occurs, causing problems in practical use. [Black dots] Rank A: No black spots with a diameter of 0.3 mm or more are observed. Rank B: Black spots with a diameter of 0.3 mm or more and less than 0.5 mm were observed, but no black spots with a diameter of 0.5 mm or more were observed. Rank C: Black spots with a diameter of 0.5 mm or more were observed.

[0075] [Comparative Example 6] The RzJIS of the outer surface obtained in Comparative Example 1 was 0.7 μm, and the outer surface had no abrasive grains or the like. Except for using the remaining cylindrical body, an electrophotographic photoreceptor was produced and evaluated in the same manner as in Example 8. The results are shown in Table 7.

[0076] [Comparative Example 7] An electrophotographic photoreceptor was produced and evaluated in the same manner as in Example 8, except that the aluminum alloy cylinder (not subjected to blasting) prepared in Example 2 was used. The results are shown in Table 7.

[0077] [Comparative Example 8] The RzJIS of the outer surface obtained in Comparative Example 5 was 2.5 μm, and the abrasive grains, etc. An electrophotographic photoreceptor was produced and evaluated in the same manner as in Example 8, except that a cylindrical body in which residual toner particles and punctures had occurred was used. The results are shown in Table 7.

[0078] [Table 7]

[0079] The following can be understood from Table 7. By using an electrophotographic photoreceptor manufactured using a substrate having a roughened outer surface and no adhesion of abrasive grains or the like to its outer surface, it has become possible to obtain a high-quality electrophotographic image free from density unevenness caused by interference fringes of the image exposure light and black spots caused by the presence of abrasive grains or the like on the substrate surface. When an electrophotographic photoreceptor manufactured using a substrate having a roughened outer surface with abrasive grains or the like attached thereto is used for forming an electrophotographic image, an electrophotographic image of low quality having black dots due to the presence of abrasive grains or the like on the substrate surface is formed. Furthermore, when an electrophotographic photoreceptor manufactured using a substrate whose outer surface is not roughened is used for forming an electrophotographic image, an electrophotographic image of low quality having density unevenness due to interference fringes of image exposure light is formed.

[0080] The present disclosure relates to the following methods and configurations. (Method 1) A surface processing method for a surface including a metal surface as a surface to be processed, The surface processing method includes: Injecting abrasive grains onto the second surface of the resin film disposed in contact with the surface to be processed, which is opposite to the first surface of the resin film facing the surface to be processed, to apply an impact force to the resin film, and transmitting the impact force to the surface to be processed through the resin film to process the surface to be processed covered with the resin film. The resin film: has a thickness of 4.0 to 13.0 μm, contains at least one resin selected from the group consisting of polyethylene terephthalate, polyimide, polyvinylidene chloride, polyether ether ketone, and high-density polyethylene, The abrasive grains are spherical particles having a number average particle diameter equal to or greater than the thickness of the resin film. A surface processing method. (Method 2) The surface processing method according to Method 1, wherein the processing includes roughening the surface to be processed. (Method 3) The surface roughness RzJIS of the surface to be processed is 0.2 μm or less, and the step is to process the surface roughness RzJIS of the surface to be processed to at least 0.3 μm or more. The surface processing method of Method 1 or 2 (Method 4) The surface processing method according to any one of Methods 1 to 3, wherein the Vickers hardness of the surface to be processed is 20 or more and 50 or less. (Method 5) The surface finishing method according to any one of Methods 1 to 4, wherein the abrasive grains contain at least one selected from the group consisting of silicon carbide, alumina, and zirconium oxide. (Method 6) The abrasive grains have a new Mohs hardness of 10 or more and a density of 5 g / cm 3 or more, the surface finishing method according to Method 1. ~5, the surface finishing method according to any one of them. (Method 7) The surface finishing method according to any one of Methods 1 to 6, wherein the metal contains aluminum. (Method 8) The surface finishing method according to any one of Methods 1 to 7, wherein the surface to be processed is the surface of the substrate of the electrophotographic photoreceptor. (Method 9) A method for manufacturing a surface-finished product, comprising: Step (i) of preparing an article having a metal surface; Step (ii) of surface-finishing the metal surface as the surface to be processed to obtain a surface-finished product having the processed metal surface, The method for manufacturing a surface-finished product, wherein Step (ii) includes a step of processing the metal surface by the method according to any one of Methods 1 to 8. (Configuration 1) A surface finishing kit used in any one of Methods 1 to 8, comprising: A resin film and abrasive grains, The resin film has a thickness of 4.0 to 13.0 μm and contains at least one resin selected from the group consisting of polyethylene terephthalate, polyimide, polyvinylidene chloride, polyether ether ketone, and high-density polyethylene. The abrasive grains are spherical particles having a number average particle diameter equal to or greater than the thickness of the resin film. (Method 10) A method for manufacturing an electrophotographic photoreceptor, wherein The electrophotographic photoreceptor has at least a substrate having a metal surface and an organic photosensitive layer on the metal surface, The manufacturing method includes: Step (i) of roughening the metal surface; Step (ii) of forming the organic photosensitive layer on the surface roughened in Step (i). The method (i) includes a step of processing the metal surface by the method described in any one of Methods 1 to 8, and is a method for manufacturing an electrophotographic photoreceptor.

Explanation of Signs

[0081] 101 Workpiece, 101-s Work surface, 103 Resin film, 201 Nozzle, 203 Compressed air supply unit, 205 Abrasive grain supply unit, 101-t Surface-processed workpiece

Claims

1. A surface processing method for a surface including a metal surface as a surface to be processed, wherein the surface processing method comprises a step of spraying abrasive grains onto a second surface of a resin film disposed in contact with the surface to be processed, said second surface being opposite to a first surface facing the surface to be processed, thereby applying an impact force to the resin film, and transmitting the impact force through the resin film to the surface to be processed to process the surface to be processed covered with the resin film; the resin film has a thickness of 4.0 to 13.0 μm, contains at least one resin selected from the group consisting of polyethylene terephthalate, polyimide, polyvinylidene chloride, polyether ether ketone, and high-density polyethylene, the abrasive grains are spherical particles having a number average particle diameter equal to or greater than the thickness of the resin film, characterized in that it is a surface processing method.

2. The surface processing method according to claim 1, wherein the processing includes roughening the surface to be processed.

3. The surface roughness RzJIS of the surface to be processed is 0.2 μm or less, and the step is to process the surface roughness RzJIS of the surface to be processed to at least 0.3 μm or more. The surface processing method according to claim 2. method.

4. The surface processing method according to claim 1, wherein the Vickers hardness of the surface to be processed is 20 or more and 50 or less.

5. The surface processing method according to claim 1, wherein the abrasive grains contain at least one selected from the group consisting of silicon carbide, alumina, and zirconium oxide.

6.

7. The abrasive grains have a new Mohs hardness of 10 or more and a density of 5 g / cm ３ The surface processing method according to claim 1, wherein the density is 5 g / cm or more. The surface processing method according to claim 1, wherein the metal contains aluminum.

8. The surface processing method according to claim 1, wherein the surface to be processed is the surface of a substrate of an electrophotographic photoreceptor.

9. A method for manufacturing a surface processed article, comprising: step (i) of preparing an article having a metal surface; and step (ii) of surface processing the metal surface as a surface to be processed to obtain a surface processed article having the processed metal surface, characterized in that step (ii) includes a step of processing the metal surface by the surface processing method according to any one of claims 1 to 8.

10. A surface processing kit for use in the surface processing method according to any one of claims 1 to 8, comprising: a resin film and abrasive grains, the resin film having a thickness of 4.0 to 13.0 μm and containing at least one resin selected from the group consisting of polyethylene terephthalate, polyimide, polyvinylidene chloride, polyether ether ketone, and high-density polyethylene, ​ The abrasive grains are spherical particles having a number average particle diameter equal to or greater than the thickness of the resin film. A surface processing kit characterized by this.

11. A method for manufacturing an electrophotographic photoreceptor, The electrophotographic photoreceptor has at least a substrate having a metal surface and an organic photosensitive layer on the metal surface. The manufacturing method is as follows. A step (i) of roughening the metal surface, A step (ii) of forming the organic photosensitive layer on the surface roughened by the step (i), and the method includes these steps. The step (i) includes a step of processing the metal surface by the surface processing method according to any one of claims 1 to 8. A method for manufacturing an electrophotographic photoreceptor characterized by this.

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