Coating device and coating method

Abstract

To obtain a coating device capable of preventing occurrence of defect resulting from bubbles in a coating film on the surface of a substrate comparing to the device in which the inside R or C chamfer and outside R or C chamfer in the top edge of a cylindrical part of a coating tank are same in dimension.SOLUTION: A coating device 10 comprises: a chuck part 16 supporting a substrate 12 formed into cylindrical shape and moving in a vertical direction; and a coating tank 18 having a cylindrical part 19 which is filled with a coating liquid 14 and in which the liquid 14 is overflowed from the upper part thereof, and in which the substrate 12 is immersed in the cylindrical part 19 from an upper side. The device is configured so that the angle R dimension of the corner part 19C inside a radial direction in the upper end 19A of the cylindrical part 19, and the angle R dimension of the corner part 19D outside the radial direction in the same upper end 19A of the cylindrical part 19 as above are different from each other.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a coating apparatus and a coating method. [Background technology]

[0002] The following Patent Document 1 discloses a dip coating apparatus for manufacturing an electrophotographic photoreceptor having a substantially cylindrical dip coating tank for manufacturing an electrophotographic photoreceptor in which an undercoat layer, a charge generating layer, or a charge transport layer is formed by dip coating on a conductive support for the electrophotographic photoreceptor. In the dip coating apparatus for manufacturing an electrophotographic photoreceptor described in this document, the upper end of the dip coating tank has at least one or more dams provided at non-uniform intervals, and the dams can be removed and / or the size can be controlled. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4075322 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if bubbles remaining on the upper surface of the cylindrical portion of the coating tank adhere to the surface of the substrate, there is a concern that defects may occur in the coating film on the surface of the substrate.

[0005] In consideration of the above-mentioned facts, the present invention aims to provide a coating device and coating method that can suppress the occurrence of defects caused by bubbles in the coating film on the surface of a substrate, compared to a coating tank in which the inner R or C chamfer and the outer R or C chamfer at the upper end of the cylindrical portion are the same dimensions. [Means for solving the problem]

[0006] The coating device of the first embodiment is equipped with a chuck portion that supports a cylindrically formed substrate and moves in an up-down direction, and a coating tank having a cylindrical portion that is filled with a coating liquid from which the coating liquid overflows from the top, in which the substrate is immersed in the cylindrical portion from above, and in which, when viewed in a cross-sectional view cut along the up-down direction, the corner R dimension or C chamfer dimension of a radially inner corner at the upper end of the cylindrical portion and the corner R dimension or C chamfer dimension of a radially outer corner at the upper end of the cylindrical portion are different from each other.

[0007] The second aspect of the coating device is the coating device of the first aspect, wherein the radially inner corner and the radially outer corner at the upper end of the tubular portion are formed with an R-shaped corner, and the corner R dimension of the radially inner corner at the upper end of the tubular portion is set to be smaller than the corner R dimension of the radially outer corner at the upper end of the tubular portion.

[0008] The coating device of the third aspect is a coating device of the first or second aspect, wherein the area between the radially inner corner and the radially outer corner at the upper end of the tubular portion is flat with the surface facing upward.

[0009] A coating method of a fourth aspect uses a coating device of any one of the first to third aspects, and includes a first step of inserting the substrate into the cylindrical portion, and a second step of pulling the substrate out of the cylindrical portion.

[0010] A coating method of a fifth aspect is characterized in that, in the first step of the coating method of the fourth aspect, the average ascending speed of the coating liquid rising between the radially outer surface of the substrate and the radially inner surface of the cylindrical portion is set to 50 cm / min or more. Effect of the Invention

[0011] The coating device of the first embodiment can suppress the occurrence of defects caused by bubbles in the coating film on the surface of the substrate, compared to a coating tank in which the inner R or C chamfer and the outer R or C chamfer at the upper end of the cylindrical portion are the same dimensions.

[0012] The coating device of the second aspect can suppress defects caused by bubbles in the coating film on the surface of the substrate, compared to a configuration in which the corner R dimension of the radially inner corner at the upper end of the tubular portion is set to a dimension larger than the corner R dimension of the radially outer corner at the upper end of the tubular portion.

[0013] The coating device of the third aspect can suppress defects caused by bubbles in the coating film on the surface of the substrate compared to a configuration in which no flat portion is provided between the radially inner corner and the radially outer corner at the upper end of the tubular portion.

[0014] The coating method of the fourth aspect is able to prevent defects caused by bubbles in the coating film on the surface of the substrate compared to a method in which the inner R or C-chamfer and the outer R or C-chamfer at the upper end of the cylindrical portion of the coating tank are of the same dimensions.

[0015] The coating method of the fifth aspect can suppress defects caused by bubbles in the coating film on the surface of the substrate, compared to a method in which the average ascending speed of the coating liquid rising between the radially outer surface of the substrate and the radially inner surface of the tubular portion is less than 50 cm / min. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a side cross-sectional view that shows a schematic view of the coating device, illustrating a state before a substrate is inserted into a cylindrical portion. [Diagram 2] 2 is a side cross-sectional view corresponding to FIG. 1, illustrating a state when the insertion of the base material into the cylindrical portion is completed. FIG. [Diagram 3] 2 is a side cross-sectional view corresponding to FIG. 1, illustrating a state when the substrate has been completely pulled up from the cylindrical portion. [Figure 4] 1 is a side cross-sectional view showing a cross section taken along the up-down direction of an upper end portion of a cylindrical portion to which the configuration of Example 1 is applied. [Diagram 5] 11 is a side cross-sectional view showing a cross section taken along the up-down direction of an upper end portion of a cylindrical portion to which the configuration of Example 2 is applied. FIG. [Figure 6]11 is a side cross-sectional view showing a cross section taken along the up-down direction of an upper end portion of a cylindrical portion to which the configuration of Example 3 is applied. FIG. [Figure 7] 13 is a side cross-sectional view showing a cross section taken along the up-down direction of an upper end portion of a cylindrical portion to which the configuration of Example 4 is applied. FIG. [Figure 8] 13 is a cross-sectional view showing a cross section of an upper end portion of a cylindrical part to which the configuration of Example 5 is applied, cut along the vertical direction. FIG. [Figure 9] FIG. 2 is a cross-sectional view showing a schematic diagram of each layer of a coating film applied to the surface of a substrate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment for implementing the technology of the present disclosure will be described. In the following description, the direction indicated by the arrow X in the drawings as appropriate is the device width direction, and the direction indicated by the arrow Y is the device height direction. In addition, the direction perpendicular to each of the device width direction and the device height direction (arrow Z direction) is the device depth direction.

[0018] 1, the coating device 10 of this embodiment is a device used for coating a coating liquid 14 on a radially outer surface 12D of a cylindrical substrate 12. The coating device 10 includes a chuck portion 16 for gripping an upper end portion 12A of the substrate 12, a coating tank 18 to which the coating liquid 14 is supplied, and a liquid receiving portion 20 for receiving the coating liquid 14 that has overflowed from the coating tank 18. The coating device 10 also includes an evaporation suppressing member 22 for suppressing evaporation of the coating liquid 14, and a fixed hood 24 for covering the coating tank 18 from above.

[0019] The chuck portion 16 is configured to be able to grip the upper end portion 12A of the substrate 12 by, for example, operation of compressed air or an electric actuator. In this embodiment, the multiple chuck portions 16 are arranged at intervals in the device width direction and device depth direction. The multiple chuck portions 16 are held by a chuck holding member 30. The number of chuck portions 16 may be appropriately set in consideration of the number of substrates 12 to be processed simultaneously.

[0020] The coating tank 18 is filled with the coating liquid 14 by supplying the coating liquid 14 from the lower side, and includes a cylindrical portion 19 from which the coating liquid 14 overflows from the upper portion. The inner diameter of the cylindrical portion 19 is set to be larger than the outer diameter of the substrate 12, and the depth of the cylindrical portion 19 is set to be deeper than the length of the substrate 12. This allows the substrate 12 to be immersed in the cylindrical portion 19 from above. In this embodiment, a plurality of cylindrical portions 19 are arranged at intervals in the width direction and the depth direction of the device. The number of cylindrical portions 19 may be appropriately set in consideration of the number of substrates 12 to be simultaneously processed, similar to the number of chuck portions 16.

[0021] The liquid receiving portion 20 includes a plate-shaped bottom surface portion 20A that spreads in the width direction and the depth direction of the apparatus at the middle portion of the vertical direction of the cylindrical portion 19, and a side surface portion 20B that rises upward from the ends of the bottom surface portion 20A in the width direction and the depth direction of the apparatus. The bottom surface portion 20A is formed with a plurality of through holes 20C through which the plurality of cylindrical portions 19 are inserted. The gap between the outer peripheral surface of the cylindrical portion 19 and the through holes 20C is blocked. The bottom surface portion 20A is inclined downward as it approaches one side in the width direction of the apparatus. A return pipe 36 is connected to the side surface portion 20B on one side in the width direction of the apparatus. The coating liquid 14 that overflows from the upper end of the cylindrical portion 19 and reaches the bottom surface portion 20A flows along the bottom surface portion 20A toward one side in the width direction of the apparatus, and is collected from the return pipe 36 to a liquid holding tank (not shown). The coating liquid 14 recovered from the return pipe 36 to the liquid holding tank is sent again toward each cylindrical portion 19 of the coating tank 18. That is, the coating liquid 14 circulates between the cylindrical portion 19 of the coating tank 18 and the liquid holding tank.

[0022] The evaporation suppressing member 22 includes a plurality of covering cylindrical portions 22A formed in a cylindrical shape surrounding the plurality of cylindrical portions 19 from the radial outside, and a bottom surface portion 22B connecting the plurality of covering cylindrical portions 22A and extending in the device width direction and device depth direction. The bottom surface portion 22B covers the liquid receiving portion 20 from the upper side. The coating liquid 14 overflowing from the upper end of the cylindrical portion 19 flows through the gap between the covering cylindrical portion 22A and the cylindrical portion 19, so that the solvent vapor evaporated from the coating liquid 14 is sucked downward from the gap between the covering cylindrical portion 22A and the cylindrical portion 19. The solvent vapor sucked downward from the gap between the covering cylindrical portion 22A and the cylindrical portion 19 is collected through the return pipe 36 and reused as a solvent for the coating liquid 14.

[0023] The fixed hood 24 includes a plurality of hood portions 24A arranged above the plurality of cylindrical portions 19 so that their axes coincide with the respective cylindrical portions 19 within a range of a set tolerance, and a lid portion 24B connecting the plurality of hood portions 24A and covering the evaporation suppressing member 22 and the plurality of cylindrical portions 19 from above. The hood portion 24A of the fixed hood 24 is formed in a cylindrical shape. The inner diameter of the hood portion 24A is set to be larger than the outer diameter of the base material 12.

[0024] Next, a coating method using the coating apparatus 10 described above will be described.

[0025] As shown in FIG. 1, first, the plurality of substrates 12 held by the plurality of chuck portions 16 are moved above the respective cylindrical portions 19 .

[0026] 2, the multiple chuck portions 16 are lowered to lower the multiple base materials 12 held by the multiple chuck portions 16, respectively, and the multiple base materials 12 are inserted into the respective cylindrical portions 19. This step is an insertion step as a first step.

[0027] 3, the multiple chuck portions 16 are raised to raise the multiple substrates 12 held by the multiple chuck portions 16, respectively, and the multiple substrates 12 are pulled up from the respective cylindrical portions 19. This step is a pulling-up step as the second step.

[0028] Through the above steps, the coating liquid 14 is applied to the radially outer surfaces 12D of the plurality of substrates 12, and a coating film 15 is formed on the radially outer surfaces 12D of the plurality of substrates 12. Note that in the above steps, the coating liquid 14 for forming a charge generation layer 54 (see FIG. 9), which will be described later, is used to apply the coating liquid 14 to the radially outer surfaces 12D of the plurality of substrates 12.

[0029] (Configuration and method for facilitating foam discharge) Next, a description will be given of a configuration and a method for easily discharging bubbles 14B on the upper surface 14A of the coating liquid 14 spilling out from the upper end 19A of the cylindrical portion 19. The configurations and methods of each embodiment described below are applied to the coating device 10 and the coating method described above.

[0030] Example 1 FIG. 4 shows a cross section of the upper end 19B of the cylindrical portion 19 to which the configuration of Example 1 for facilitating the discharge of the bubbles 14B is applied. As shown in this figure, in the cylindrical portion 19 of this embodiment, the radially inner corner 19C and the radially outer corner 19D at the upper end 19A of the cylindrical portion 19 are R-chamfered. In the cylindrical portion 19 of this embodiment, the corner R dimension R1 of the radially inner corner 19C at the upper end 19A of the cylindrical portion 19 and the corner R dimension R2 of the radially outer corner 19D are set to different dimensions. Specifically, the corner R dimension R1 of the radially inner corner 19C at the upper end 19A of the cylindrical portion 19 is set to 2.5 mm, and the corner R dimension R2 of the radially outer corner 19D is set to 3 mm. Here, in a preliminary test or the like, the outer diameter dimension D1 of the bubble 14B floating on the upper surface 14A of the coating liquid 14 is measured. The average value of the outer diameter dimension D1 of the bubbles 14B is set to D2. It was discovered that the bubbles 14B floating on the upper surface 14A of the coating liquid 14 can be easily discharged by setting the corner R dimension R1 of the radially inner corner 19C at the upper end 19A of the cylindrical portion 19 and the corner R dimension R2 of the radially outer corner 19D at the upper end 19A of the cylindrical portion 19 to 1 / 3 or more of the average value D2 of the outer diameter dimension D1 of the bubbles 14B, more preferably to 1 / 2 or more. In this embodiment, since the average value D2 of the outer diameter dimension D1 of the bubbles 14B was 5 mm, the corner R dimension R1 of the radially inner corner 19C at the upper end 19A of the cylindrical portion 19 and the corner R dimension R2 of the radially outer corner 19D at the upper end 19A of the cylindrical portion 19 are set to 2.5 mm or more.

[0031] In this embodiment, the upper end 19A of the cylindrical portion 19 has a flat portion 19E between a radially inner corner 19C and a radially outer corner 19D, the flat portion 19E having a flat surface facing upward. The flat portion 19E has a ring shape when viewed from above. The radial width W of the cylindrical portion 19 at the flat portion 19E is set to 3 mm.

[0032] In Fig. 4, the substrate 12 being inserted into the cylindrical portion 19 in the above-mentioned insertion step (see Fig. 2) is shown by a two-dot chain line. In this embodiment, in the insertion step, the amount of coating liquid 14 supplied to the cylindrical portion 19 is adjusted so that the average rising speed V of the coating liquid 14 rising between the radially outer surface 12D of the substrate 12 and the radially inner surface 19F of the cylindrical portion 19 is a predetermined speed. The average rising speed V [cm / min] of the coating liquid 14 is calculated by the amount of coating liquid 14 supplied to the cylindrical portion 19 Q [cm 3 / min], and the area between a radially outer surface 12D of the base material 12 and a radially inner surface 19F of the cylindrical portion 19 in a cross-sectional view of the portion of the cylindrical portion 19 into which the base material 12 is inserted is cut along the device width direction and device depth direction. 2 ] and the volume insertion rate of the substrate is X cm 3 / min, and the inner cross-sectional area of ​​the cylindrical portion 19A is Y cm 2 Then, it is calculated using the following (Equation 1). (Equation 1) V = (Q + X) / (YA) In this embodiment, the average rising speed V of the coating liquid 14 is set to a predetermined value of 50 cm / min or more.

[0033] Example 2 5 shows a cross section of an upper end 19B of a cylindrical portion 19 to which the configuration of Example 2 for facilitating the discharge of bubbles 14B is applied. As shown in this figure, the cylindrical portion 19 of this example is configured similarly to the cylindrical portion 19 of Example 1 (see FIG. 4) described above, except that it does not include a flat portion 19E. Note that the same reference numerals as those of the cylindrical portion 19 of Example 1 are used for the portions of the cylindrical portion 19 of Example 2 that correspond to those of the cylindrical portion 19 of Example 1 (see FIG. 4).

[0034] Example 3 6 shows a cross section of an upper end 19B of a cylindrical portion 19 to which the configuration of Example 3 for facilitating the discharge of bubbles 14B is applied. As shown in this figure, the cylindrical portion 19 of this example is configured similarly to the cylindrical portion 19 of Example 1 (see FIG. 4) described above, except that the corner R dimension R1 of a radially inner corner 19C at an upper end 19A of the cylindrical portion 19 is set to 3 mm, and the corner R dimension R2 of a radially outer corner 19D is set to 2.5 mm. Note that the same reference numerals as those of the cylindrical portion 19 of Example 1 are used for the portions of the cylindrical portion 19 of Example 3 that correspond to those of the cylindrical portion 19 of Example 1 (see FIG. 4).

[0035] (Effects of this embodiment) Next, the effects of the above-mentioned Examples 1 to 3 will be described.

[0036] First, in order to confirm the effects of the above-mentioned Examples 1 and 2, a test was conducted to check the ratio of bubbles 14B discharged from the upper surface 14A of the coating liquid 14 from the start to the completion of the insertion process. The completion of the insertion process refers to the time when the substrate 12 is lowered to the lowest position, as shown in FIG. 2.

[0037] In this test, first, a predetermined number of bubbles 14B were floated on the upper surface 14A of the coating liquid 14. The bubbles 14B were formed with a dropper. Next, an insertion step was performed, and the number of bubbles 14B floating on the upper surface 14A of the coating liquid 14 at the completion of the insertion step was counted to calculate the proportion of the bubbles 14B that were expelled.

[0038] Table 1 below shows the conditions and results of the above test performed using the cylindrical portion 19 of Example 1, Example 2, and Comparative Example. The cylindrical portion 19 of the Comparative Example is configured similarly to the cylindrical portion 19 of Example 1, except that the corner R dimension R1 of the radially inner corner 19C at the upper end 19A of the cylindrical portion 19 is set to 0.5 mm, and the corner R dimension R2 of the radially outer corner 19D is set to 0.5 mm. This test was performed by setting the average rising speed V of the coating liquid 14 to 30 [cm / min], 40 [cm / min], 50 [cm / min], and 60 [cm / min] for each of the cylindrical portions 19 of Example 1, Example 2, and Comparative Example. [Table 1]

[0039] As shown in Table 1 above, the cylindrical portions 19 of Examples 1 and 2 have a higher rate of being able to discharge bubbles 14B floating on the upper surface 14A of the coating liquid 14 than the cylindrical portion 19 of the comparative example. This shows that the cylindrical portions 19 of Examples 1 and 2 can increase the rate of being able to discharge bubbles 14B floating on the upper surface 14A of the coating liquid 14 compared to the cylindrical portion 19 of the comparative example in which the corner R dimension R1 and the corner R dimension R2 at the upper end 19A of the cylindrical portion 19 are the same. This makes it possible to suppress defects caused by bubbles 14B from occurring in the coating film 15 on the radially outer surface 12D of the substrate 12.

[0040] Furthermore, as shown in Table 1 above, the cylindrical portion 19 of Example 1 is able to discharge a higher proportion of bubbles 14B floating on the upper surface 14A of the coating liquid 14 than the cylindrical portion 19 of Example 2. This shows that the cylindrical portion 19 of Example 1 is able to discharge a higher proportion of bubbles 14B floating on the upper surface 14A of the coating liquid 14 than the cylindrical portion 19 of Example 2 in which the flat portion 19E is not provided.

[0041] Table 2 below shows the conditions and results of the above test conducted using the cylindrical portion 19 of Example 1 and Example 3. Note that this test was conducted for each of the cylindrical portions 19 of Example 1 and Example 3 by setting the average ascending speed V of the coating liquid 14 to 35 [cm / min], 40 [cm / min], 45 [cm / min], 50 [cm / min], and 60 [cm / min], respectively. [Table 2]

[0042] As shown in Table 2 above, the cylindrical portion 19 of Example 1 is able to discharge a higher proportion of bubbles 14B floating on the upper surface 14A of the coating liquid 14 than the cylindrical portion 19 of Example 3. This shows that the cylindrical portion 19 of Example 1 is able to discharge a higher proportion of bubbles 14B floating on the upper surface 14A of the coating liquid 14 than the configuration of the cylindrical portion 19 of Example 3 in which the corner R dimension R1 is set to be larger than the corner R dimension R2.

[0043] Furthermore, as shown in Tables 1 and 2 above, in the cylindrical portion 19 of Comparative Example 1, by setting the average rising speed V of the coating liquid 14 to 50 [cm / min] or more, it is possible to expel 100% of the bubbles 14B floating on the upper surface 14A of the coating liquid 14.

[0044] As described above, the coating device 10 described above can suppress the occurrence of defects due to bubbles 14B in the coating film 15 on the surface of the substrate 12, compared to a coating tank 18 in which the corner R dimension R1 and the corner R dimension R2 at the upper end 19A of the cylindrical portion 19 are the same dimension.

[0045] Furthermore, the coating device 10 described above can suppress the occurrence of defects due to bubbles 14B in the coating film 15 on the surface of the substrate 12, compared to the configuration of the cylindrical portion 19 of Example 3 in which the corner R dimension R1 is set to a dimension larger than the corner R dimension R2.

[0046] Furthermore, the coating device 10 described above can suppress the occurrence of defects due to bubbles 14B in the coating film 15 on the surface of the substrate 12, compared to a configuration in which a flat portion 19E is not provided between the radially inner corner 19C and the radially outer corner 19D at the upper end 19A of the tubular portion 19.

[0047] Furthermore, the coating method described above can suppress the occurrence of defects due to bubbles 14B in the coating film 15 on the surface of the substrate 12, compared to a method in which the corner R dimension R1 and the corner R dimension R2 at the upper end 19A of the cylindrical portion 19 of the coating tank 18 are the same.

[0048] Furthermore, the coating method described above can suppress the occurrence of defects in the coating film 15 on the surface of the substrate 12 due to bubbles 14B, compared to a method in which the average ascending speed V of the coating liquid 14 is set to less than 50 cm / min.

[0049] In the above-described embodiments, the radially inner corner 19C and the radially outer corner 19D at the upper end 19A of the cylindrical portion 19 are rounded, but the embodiments of the present disclosure are not limited thereto. For example, as in the cylindrical portion 19 to which the configuration of the fourth embodiment shown in FIG. 7 is applied and the cylindrical portion 19 to which the configuration of the fifth embodiment shown in FIG. 8 is applied, the radially inner corner 19C and the radially outer corner 19D at the upper end 19A of the cylindrical portion 19 may be C-chamfered. In the cylindrical portion 19 to which the configuration of the fourth embodiment shown in FIG. 7 is applied, the C-chamfer dimension C1 of the radially inner corner 19C at the upper end 19A of the cylindrical portion 19 is set to be larger than the C-chamfer dimension C2 of the radially outer corner 19D. In addition, in the tubular portion 19 to which the configuration of Example 5 shown in Figure 8 is applied, the C chamfer dimension C1 of the radially inner corner 19C at the upper end 19A of the tubular portion 19 is set to a smaller angle dimension than the C chamfer dimension C2 of the radially outer corner 19D.

[0050] (Example of application to electrophotographic photoreceptors) Next, an example in which the above-mentioned coating apparatus 10 and coating method are applied to the manufacture of an electrophotographic photoreceptor 48 (see FIG. 9) will be described.

[0051] 9, any material that has been conventionally used may be used as the conductive substrate 12. Examples include metals such as aluminum, nickel, chromium, and stainless steel, and plastic films provided with thin films of aluminum, titanium, nickel, chromium, stainless steel, gold, vanadium, tin oxide, indium oxide, ITO, and the like, as well as paper and plastic films coated or impregnated with a conductive agent. The shape of the substrate 12 is not limited to a drum (cylinder) shape, and may be a sheet or plate shape.

[0052] When a metal pipe is used as the substrate 12, the surface may be left as is or may have been previously treated by mirror cutting, etching, anodizing, rough cutting, centerless grinding, sandblasting, wet honing, or the like.

[0053] The undercoat layer 50 is provided as necessary for the purpose of preventing light reflection on the surface of the substrate 12 and preventing unnecessary carriers from flowing from the substrate 12 into the photosensitive layer 52. Examples of materials for the undercoat layer 50 include metal powders such as aluminum, copper, nickel, and silver, conductive metal oxides such as antimony oxide, indium oxide, tin oxide, and zinc oxide, and conductive materials such as carbon fiber, carbon black, and graphite powder dispersed in a binder resin and applied to the substrate. Two or more types of metal oxide particles can also be mixed and used. Furthermore, the powder resistance can be controlled by subjecting the metal oxide particles to surface treatment with a coupling agent. In the following description, the undercoat layer 50 may be referred to as a UCL (Under Coat Layer).

[0054] Examples of the binder resin contained in the undercoat layer 50 include known polymer resin compounds such as acetal resins such as polyvinyl butyral, polyvinyl alcohol resins, casein, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, phenolic resins, phenol-formaldehyde resins, melamine resins, and urethane resins, as well as charge transporting resins having charge transporting groups and conductive resins such as polyaniline. Among these, resins that are insoluble in the coating solvent of the upper layer are preferably used, and in particular, phenolic resins, phenol-formaldehyde resins, melamine resins, urethane resins, and epoxy resins are preferably used.

[0055] The ratio of the metal oxide particles to the binder resin in the undercoat layer 50 is not particularly limited, and can be set arbitrarily within a range that provides desired electrophotographic photoreceptor characteristics.

[0056] When forming the undercoat layer 50, a coating liquid in which the above components are added to a predetermined solvent is used. Examples of such solvents include organic solvents such as aromatic hydrocarbon solvents such as toluene and chlorobenzene, aliphatic alcohol solvents such as methanol, ethanol, n-propanol, iso-propanol, and n-butanol, ketone solvents such as acetone, cyclohexanone, and 2-butanone, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform, and ethylene chloride, cyclic or linear ether solvents such as tetrahydrofuran, dioxane, ethylene glycol, and diethyl ether, and ester solvents such as methyl acetate, ethyl acetate, and n-butyl acetate. These solvents can be used alone or in combination of two or more. When mixing, any solvent can be used as long as it can dissolve the binder resin as a mixed solvent.

[0057] As a method for dispersing the metal oxide particles in the coating liquid for forming the undercoat layer, a media dispersing machine such as a ball mill, a vibration ball mill, an attritor, a sand mill, or a horizontal sand mill, or a media-less dispersing machine such as an agitator, an ultrasonic dispersing machine, a roll mill, or a high-pressure homogenizer, can be used. Furthermore, examples of the high-pressure homogenizer include a collision type in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision under high pressure, and a penetration type in which the dispersion liquid is dispersed by penetrating a fine flow path under high pressure.

[0058] Methods for applying the thus obtained coating solution for forming an undercoat layer onto the substrate 12 include a dip coating method using the above-mentioned coating device 10, a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, and a curtain coating method. The thickness of the undercoat layer 50 is preferably 15 μm or more, and more preferably 20 to 50 μm. Resin particles can also be added to the undercoat layer 50 to adjust the surface roughness. As the resin particles, silicone resin particles, crosslinked PMMA resin particles, etc. can be used.

[0059] The charge generating layer 54 is formed by dispersing a charge generating material in a suitable binder resin. As such a charge generating material, phthalocyanine pigments such as metal-free phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, dichlorotin phthalocyanine, titanyl phthalocyanine, etc., can be used. In particular, chlorogallium phthalocyanine crystals having strong diffraction peaks at Bragg angles (2θ±0.2°) of at least 7.4°, 16.6°, 25.5°, and 28.3° for CuKα characteristic X-rays, and chlorogallium phthalocyanine crystals having strong diffraction peaks at Bragg angles (2θ±0.2°) of at least 7.7°, 9.3°, 16. Metal-free phthalocyanine crystals having strong diffraction peaks at 9°, 17.5°, 22.4° and 28.8°, hydroxygallium phthalocyanine crystals having strong diffraction peaks at Bragg angles (2θ±0.2°) of at least 7.5°, 9.9°, 12.5°, 16.3°, 18.6°, 25.1° and 28.3° to CuKα characteristic X-rays, and titanyl phthalocyanine crystals having strong diffraction peaks at Bragg angles (2θ±0.2°) of at least 9.6°, 24.1° and 27.2° to CuKα characteristic X-rays can be used. Other charge generating materials include quinone pigments, perylene pigments, indigo pigments, bisbenzimidazole pigments, anthrone pigments, quinacridone pigments, etc. These charge generating materials can be used alone or in combination of two or more kinds. In the following description, the charge generating layer 54 may be called a CGL (Charge Generation Layer).

[0060] Examples of the binder resin in the charge generating layer 54 include polycarbonate resins such as bisphenol A type or bisphenol Z type, acrylic resins, methacrylic resins, polyarylate resins, polyester resins, polyvinyl chloride resins, polystyrene resins, acrylonitrile-styrene copolymer resins, acrylonitrile-butadiene copolymers, polyvinyl acetate resins, polyvinyl formal resins, polysulfone resins, styrene-butadiene copolymer resins, vinylidene chloride-acrylonitrile copolymer resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, phenol-formaldehyde resins, polyacrylamide resins, polyamide resins, and poly-N-vinylcarbazole resins. These binder resins can be used alone or in combination of two or more. The compounding ratio of the charge generating material to the binder resin is preferably in the range of 10:1 to 1:10.

[0061] When forming the charge generating layer 54, a coating liquid in which the above components are added to a predetermined solvent is used. Examples of such solvents include organic solvents such as aromatic hydrocarbon solvents such as toluene and chlorobenzene, aliphatic alcohol solvents such as methanol, ethanol, n-propanol, iso-propanol, and n-butanol, ketone solvents such as acetone, cyclohexanone, and 2-butanone, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform, and ethylene chloride, cyclic or linear ether solvents such as tetrahydrofuran, dioxane, ethylene glycol, and diethyl ether, and ester solvents such as methyl acetate, ethyl acetate, and n-butyl acetate. These solvents can be used alone or in combination of two or more. When mixing, any solvent can be used as long as it can dissolve the binder resin as a mixed solvent.

[0062] In order to disperse the charge generating material in the resin, the coating liquid is subjected to a dispersion treatment. As a dispersion method, a media dispersing machine such as a ball mill, a vibration ball mill, an attritor, a sand mill, or a horizontal sand mill, or a media-less dispersing machine such as an agitator, an ultrasonic dispersing machine, a roll mill, or a high-pressure homogenizer, can be used. Furthermore, examples of high-pressure homogenizers include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision under high pressure, and a penetration method in which the dispersion is dispersed by penetrating a fine flow path under high pressure.

[0063] Methods for applying the coating liquid thus obtained onto the undercoat layer 50 include dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, curtain coating, and the like, using the above-mentioned coating apparatus 10. The thickness of the charge generating layer 54 is set in the range of preferably 0.01 to 5 μm, and more preferably 0.05 to 2.0 μm.

[0064] The charge transport layer 56 corresponds to the surface layer in the electrophotographic photoreceptor 48, and contains the copolymer according to this embodiment and fluorine-based resin particles as described above. The copolymer according to this embodiment is a fluorine-based graft polymer containing repeating units represented by structural formula A and structural formula B, and is a resin synthesized by, for example, graft polymerization using a macromonomer made of an acrylic acid ester compound, a methacrylic acid ester compound, etc., and perfluoroalkylethyl (meth)acrylate, or perfluoroalkyl (meth)acrylate. Here, (meth)acrylate refers to acrylate or methacrylate.

[0065] In the copolymer according to this embodiment, the content ratio of Structural Formula A to Structural Formula B, i.e., l:m, is preferably (A) 1:9 to 9:1, more preferably 3:7 to 7:3. When l:m is in the range of (A) 3:7 to 7:3, the tetrafluoroethylene resin can be dispersed in both rows.

[0066] In the structural formula A and the structural formula B, examples of the alkyl group represented by R1, R2, R3, and R4 include a methyl group, an ethyl group, a propyl group, etc. R1, R2, R3, and R4 are preferably a hydrogen atom or a methyl group, and among these, a methyl group is more preferable.

[0067] The content of the copolymer according to this embodiment in the surface layer, i.e., the charge transport layer 56, is preferably 1% by mass or more and 5% by mass or less with respect to the content (mass basis) of the fluororesin particles in the surface layer. The average molecular weight of the fluororesin graft polymer is preferably 20,000 to 80,000, more preferably 50,000 to 70,000. In this embodiment, the average molecular weight of the fluororesin particles refers to a value measured by GPC.

[0068] The content of the fluororesin particles relative to the total solid content of the surface layer, i.e., the charge transport layer 56, is preferably 1% by mass or more and 15% by mass or less, and more preferably 2% by mass or more and 12% by mass or less. If the content of the fluororesin particles is 2% by mass or more, the surface energy of the charge transport layer 56 can be reduced, and the durability of the electrophotographic photoreceptor can be improved. In addition, if the content of the fluororesin particles is 15% by mass or less, a decrease in light transmittance and a decrease in film strength are unlikely to occur.

[0069] The fluororesin particles are preferably one or more selected from tetrafluoroethylene resin (PTFE), trifluorochloroethylene resin, hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorodichloroethylene resin and copolymers thereof, more preferably tetrafluoroethylene resin and vinylidene fluoride resin, and particularly preferably tetrafluoroethylene resin. When the fluororesin particles according to this embodiment contain tetrafluoroethylene resin, the effect of wear resistance is obtained.

[0070] The method for applying the thus obtained charge transport layer forming coating liquid onto the charge generation layer 54 is preferably a dip coating method using the above-mentioned coating apparatus 10. Other methods for applying the coating onto the charge generation layer 54 include a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, a curtain coating method, etc. The thickness of the charge transport layer 56 is preferably 15 μm or more, more preferably 20 to 50 μm.

[0071] Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and it is of course possible to implement the present invention in various other modified forms without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0072] 10 Coating equipment 12 Base material 12D Radial outer surface of substrate 14 Coating fluid 16 Chuck part 18 Coating tank 19 Cylindrical section 19A Upper end of the cylindrical part 19C Radially inner corner at the upper end of the cylindrical portion 19D Radially outer corner at the upper end of the cylindrical part 19F Radial inner surface of cylindrical part R1: Radial inner corner radius dimension at the top end of the cylindrical part R2: The radius of the outer corner of the upper end of the cylindrical part C1: Chamfer dimension of the radially inner corner at the top end of the cylindrical part C2 Chamfering dimension of the radially outer corner at the top end of the cylindrical part

Claims

1. A chuck portion that supports a cylindrically formed substrate and moves in a vertical direction; a coating tank having a cylindrical portion which is filled with a coating liquid and from which the coating liquid overflows from the top, the substrate being immersed in the cylindrical portion from above, the coating tank having a corner R dimension or C chamfer dimension of a radially inner corner at the upper end of the cylindrical portion and a corner R dimension or C chamfer dimension of a radially outer corner at the upper end of the cylindrical portion which are different from each other in a cross-sectional view cut along a vertical direction; Equipped with A coating device in which the portion between a radially inner corner and a radially outer corner at the upper end of the cylindrical portion is flat with an upward surface.

2. A radially inner corner and a radially outer corner at an upper end of the cylindrical portion are rounded, 2. The coating device according to claim 1, wherein a radius of curvature of a radially inner corner at the upper end of the cylindrical portion is set to be smaller than a radius of curvature of a radially outer corner at the upper end of the cylindrical portion.

3. Using the coating device according to claim 1 or 2, a first step of inserting the base material into the cylindrical portion; a second step of pulling the substrate out of the cylindrical portion; The coating method according to claim 1,

4. The coating method according to claim 3 , wherein in the first step, an average ascending speed of the coating liquid rising between the radially outer surface of the substrate and the radially inner surface of the cylindrical portion is set to 50 cm / min or more.

5. A chuck portion that supports a cylindrically formed substrate and moves in an up-down direction; a coating tank having a cylindrical portion which is filled with a coating liquid and from which the coating liquid overflows from the top, the substrate being immersed in the cylindrical portion from above, the coating tank having a corner R dimension or C chamfer dimension of a radially inner corner at the upper end of the cylindrical portion and a corner R dimension or C chamfer dimension of a radially outer corner at the upper end of the cylindrical portion which are different from each other in a cross-sectional view cut along a vertical direction; Using a coating device equipped with a first step of inserting the base material into the cylindrical portion; a second step of pulling the substrate out of the cylindrical portion; having The coating method, in the first step, wherein an average ascending speed of the coating liquid rising between the radially outer surface of the substrate and the radially inner surface of the cylindrical portion is set to 50 cm / min or more.

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