JP2011164326A - Electrophotographic photoreceptor and method for manufacturing electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoreceptor having a concavo-convex surface layer, a slippery blade for high-speed processing, and improved cleanability to form an image with stable quality, and a method for manufacturing the photoreceptor. <P>SOLUTION: The electrophotographic photoreceptor has a photosensitive layer on a cylindrical conductive substrate. A surface layer is formed on its surface by ejecting a coating liquid for forming a surface layer using an ink jet head, and hardening deposited droplets. In the surface layer, the droplets of the coating liquid for forming a surface layer are deposited and hardened so as not to bring adjacent droplets into contact with each other. The surface layer has a convex structure formed by stacking a plurality of the hardened droplets. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an electrophotographic photosensitive member, and more particularly to an electrophotographic photosensitive member used in an electrophotographic image forming apparatus in a copying machine, a laser beam printer, a facsimile, and the like, and a method for manufacturing the electrophotographic photosensitive member.

  In recent years, there has been a remarkable development in information processing system machines using an electrophotographic image forming apparatus using an electrophotographic image forming process. An electrophotographic image forming apparatus forms an image on a recording medium (for example, recording paper, an OHP sheet, etc.) using an electrophotographic image forming process. Examples of the electrophotographic image forming apparatus include, for example, an electrophotographic copying machine, an electrophotographic printer (for example, a laser printer, an LED printer, etc.), a facsimile apparatus, a word processor, and a complex machine thereof (multifunction printer, etc.).

  As electrophotographic photoreceptors used in laser printers and digital copying machines of these electrophotographic image forming apparatuses, inorganic photoreceptors using inorganic compounds such as selenium compounds have been used in the past. Organic photoreceptors that use organic compounds that are easy to develop materials that can handle light of various wavelengths and that have little impact on the environment are widely used.

  In an electrophotographic image forming apparatus (hereinafter also referred to as an image forming apparatus) using an electrophotographic image forming process, a drum-shaped electrophotographic photosensitive member (hereinafter also referred to as a photosensitive member) uniformly charged by a charging unit is used. An electrostatic latent image is formed on the outer peripheral surface of the photosensitive layer by selective exposure according to image information. The electrostatic latent image is developed with toner (developer) by developing means to form a toner image. Next, the toner image is transferred to a recording medium to form an image. Then, the developer or the like remaining on the outer peripheral surface of the photosensitive layer of the photosensitive member after the toner image transfer is removed by the cleaning unit. The photoreceptor whose outer peripheral surface is cleaned by the cleaning means is used for the next image formation. That is, on the outer peripheral surface of the photosensitive layer of the photosensitive member used until the image is formed by the image forming apparatus, the image is formed by a series of repeated processes such as charging, exposure, development, transfer, and cleaning.

  In an image forming apparatus using the electrophotographic image forming process, the friction coefficient of the surface of the photosensitive layer of the photoconductor is set for the purpose of preventing unnecessary toner adhesion and reducing the amount of residual toner after transfer. Consideration is being made to reduce it. As a result, it is known that it is difficult for cleaning failure to occur when toner remaining on the photosensitive layer without being transferred is cleaned with a blade or a brush. Furthermore, since the amount of residual toner after transfer can be reduced, the amount of waste toner can be reduced, the torque for driving the photosensitive member can be reduced, and the power consumption of the image forming apparatus can be reduced. It is known that the effects can be obtained.

  In general, the toner remaining on the photosensitive layer is cleaned by a method in which a blade formed of urethane rubber or the like is brought into pressure contact with a counter direction and the toner is removed by the blade.

  On the other hand, in the development of high speed which has been developed in recent years, both the photosensitive layer and the blade are made of resin, so the lubricity is poor, and since the photosensitive layer is smooth, the blade is reversed and cleaning failure is likely to occur. .

  In order to prevent the occurrence of poor cleaning by reversing the blade, studies have been made to reduce the friction coefficient between the blade and the surface of the photosensitive layer. For example, a method of adding a lubricant to the surface of the photosensitive layer and a method of adding a lubricant to the blade are known. Lubricants such as fluorine atom-containing resins such as polytetrafluoroethylene (hereinafter referred to as fluororesins), spherical acrylic resins, polyethylene resins, metal oxide powders such as silicon oxide and aluminum oxide, and silicone oil Liquids are known. In particular, a fluororesin containing a large amount of fluorine atoms has a large effect as a lubricant because the surface energy is extremely small. However, when the friction coefficient is lowered by these methods, the friction coefficient gradually increases due to the blade being in pressure contact for a long time, the friction with the blade is increased, and the blade squeals, stagnation, etc. May occur.

  As another method, a photoconductor having a concavo-convex shape on the surface of a photosensitive layer has been studied. Japanese Patent Application Laid-Open Nos. 2004-279967 and 2008-216307 disclose a method of forming a concavo-convex shape on the surface of a photoconductor by polishing the surface of the photoconductor with a film-shaped abrasive. Japanese Patent Application Laid-Open No. 2006-267856 discloses a method of roughening the surface of the photoreceptor by causing abrasive particles to collide with the surface of the photoreceptor.

  However, in the method of polishing the surface of the photosensitive member with a film-shaped abrasive, a deep scratch may suddenly enter the surface of the photosensitive member, or the processed surface may be frustrated and a defect may occur in a minute region. Especially for the processing of the surface of the photoreceptor whose mechanical strength is improved by polymerization of the polymerizable material, it is necessary to increase the pressing pressure of the polishing sheet and the pressing pressure of the brush during the surface processing, There was a problem in the frequency of occurrence of suddenly generated flaws and scissors-like defects. In addition, in the case of a method in which abrasive particles collide with the surface of the photoconductor, in the case of surface processing of a photoconductor having a surface layer, depending on the resin material forming the surface layer, it is necessary to spray abrasive grains at high pressure. From this point of view, it is desired to spray abrasive grains at a lower pressure. In addition, when the abrasive grains are sprayed at a high pressure, the abrasive grains may be damaged, and the damaged abrasive grains may be sprayed on the surface of the photoreceptor, which may reduce the processing uniformity of the surface.

  As a further improvement, for example, after applying a surface layer coating solution containing a polymerizable material on a cylindrical support, water or alcohol is sprayed onto the coating surface using an inkjet unit or spray. Thereafter, a method of drying and forming an uneven shape on the surface is known (for example, see Patent Document 1).

The method described in Patent Document 1 has the following problems although it is certainly effective in improving the problems in the conventional method using a film-shaped abrasive and the method of causing abrasive particles to collide with each other. I found out.
1. In the case where the droplets sprayed from the ink jet unit overlap each other and in the case of a single droplet, the size and shape of the recess formed on the surface are different, and it is difficult to make the uneven shape uniform.
2. Due to the leveling of the droplets sprayed from the ink jet unit, the size and shape of the concave portions having a certain shape are different, and it becomes difficult to make the uneven shape uniform.
3. The unevenness of the uneven shape makes the blade less slidable, making it difficult to cope with higher speeds.

  From such a situation, a photosensitive member and a photosensitive member having a slidably uneven shape of a blade that can cope with high speed, a surface layer having an uneven shape on the surface on which a cleaning property is improved and an image with stable image quality can be obtained. Development of a manufacturing method is desired.

JP 2009-25710 A

  The present invention has been made in view of such a situation, and the object thereof is to have a slidability of a blade that can cope with a higher speed, improved cleaning properties, and unevenness on the surface from which an image with stable image quality can be obtained. It is to provide a photoreceptor having a surface layer having a shape and a method for producing the photoreceptor.

  The above object of the present invention has been achieved by the following constitution.

  1. An electrophotographic photosensitive member having a photosensitive layer on a cylindrical conductive substrate, and a surface layer forming coating solution is ejected onto the surface of the substrate using an ink jet head so that droplets are landed and cured to form a surface layer. In the body, the surface layer is a convex shape in which droplets of the coating liquid for forming the surface layer are landed and cured so that they do not contact each other and adjacent to each other, and a plurality of cured droplets are superimposed An electrophotographic photosensitive member having a structure.

  2. In the method for producing an electrophotographic photosensitive member in which a surface layer forming coating liquid is ejected onto the surface of a cylindrical conductive substrate by using an ink jet head, droplets are landed and cured to form a surface layer. A process for producing an electrophotographic photoreceptor, comprising a step.

1. The droplets land on the surface of the electrophotographic photosensitive member so that they do not come into contact with adjacent droplets,
1. Step of curing to form a convex object Thereafter, a surface layer having a convex structure in which a droplet of a coating liquid for forming a surface layer is landed on the convex so as not to come into contact with an adjacent droplet, and is cured and superimposed with the convex. 2. Step of forming 3. The distance described above, wherein a distance between a droplet landed on the surface of the cylindrical conductive substrate and an adjacent droplet is 1.5 to 3.0 times the diameter of the droplet. A method for producing an electrophotographic photoreceptor.

  4). 4. The method for producing an electrophotographic photosensitive member according to 2 or 3, wherein the surface layer has a 10-point average surface roughness Rz of 0.1 μm to 3.0 μm.

  5. 5. The method for producing an electrophotographic photosensitive member according to any one of 2 to 4, wherein the viscosity of the coating liquid for forming the surface layer is 3 mPa · s to 200 mPa · s.

  6). 6. The method for producing an electrophotographic photosensitive member according to any one of 2 to 5, wherein the surface layer forming coating solution contains an actinic ray curable resin or a thermosetting resin.

  It was possible to provide a method for producing a photoconductor having an uneven shape on the outermost surface, which has a sliding property of a blade capable of handling high speed, improved cleaning properties, and an image with stable image quality.

1 is a schematic cross-sectional configuration diagram illustrating an example of a full-color image forming apparatus. FIG. 2 is a schematic perspective view of the photoconductor shown in FIG. 1. It is a schematic sectional drawing which shows an example of a structure of the photosensitive layer of the photoreceptor shown in FIG. It is the schematic which shows the manufacturing method of the photoreceptor which uses an inkjet unit and has an uneven | corrugated shaped surface layer on the surface. It is a schematic plan view which shows the other example of arrangement | positioning of the inkjet head shown by FIG. It is a general | schematic enlarged plan view of the part shown by P of FIG. It is a schematic flowchart which forms the surface layer which has an uneven | corrugated shape on the surface of a cylindrical conductive base | substrate with the method of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to FIGS. 1 to 7, but the present invention is not limited thereto.

  FIG. 1 is a schematic cross-sectional configuration diagram illustrating an example of a full-color image forming apparatus.

  In the figure, reference numeral 1 denotes a full-color image forming apparatus. The full-color image forming apparatus 1 includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, an endless belt-shaped intermediate transfer body forming unit 7 as a transfer unit, and an endless belt-shaped paper feeding conveyance for conveying a recording medium P. And a belt type fixing device 24 as fixing means. A document image reading device SC is arranged on the upper part of the main body A of the full-color image forming apparatus 1.

  An image forming unit 10Y that forms a yellow image as one of different color toner images formed on each of the photoconductors 1Y, 1M, 1C, and 1K has a body having a photosensitive layer as a first image carrier. A photosensitive member 1Y fitted with a flange, a charging unit 2Y disposed around the photosensitive member 1Y, an exposure unit 3Y, a developing unit 4Y, a primary transfer roller 5Y as a primary transfer unit, and a cleaning unit 6Y.

  An image forming unit 10M that forms a magenta image as another different color toner image has a periphery of the photoreceptor 1M in which a flange having a photosensitive layer as a first image carrier is fitted. A charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer roller 5M as a primary transfer unit, and a cleaning unit 6M.

  Further, an image forming unit 10C that forms a cyan image as one of other different color toner images has a photosensitive member 1C in which a flange is fitted to a body having a photosensitive layer as a first image carrier. A charging unit 2C, an exposure unit 3C, a developing unit 4C, a primary transfer roller 5C as a primary transfer unit, and a cleaning unit 6C are arranged around the periphery.

  Further, an image forming unit 10K for forming a black image as one of other different color toner images is provided around a photoreceptor 1K having a flange fitted to a body having a photosensitive layer as a first image carrier. A charging unit 2K, an exposure unit 3K, a developing unit 4K, a primary transfer roller 5K as a primary transfer unit, and a cleaning unit 6K are disposed.

  The endless belt-shaped intermediate transfer body unit 7 has an endless belt-shaped intermediate transfer body 70 as a second image carrier having a semiconductive endless belt shape that is wound around a plurality of rollers and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10K is sequentially transferred and synthesized on the rotating endless belt-shaped intermediate transfer body 70 by the primary transfer rollers 5Y, 5M, 5C, and 5K. A color image is formed. A recording medium P such as paper as a recording medium accommodated in the paper feeding cassette 20 is fed by the paper feeding / conveying means 21, passes through a plurality of intermediate rollers 22 A, 22 B, 22 C, 22 D, and a registration roller 23, and is secondary. A color image is transferred onto the recording medium P at a time by being conveyed to a secondary transfer roller 5A as a transfer means.

  The recording medium P onto which the color image has been transferred is fixed by the fixing device 24 equipped with the heat roller fixing device 270, is sandwiched between the paper discharge rollers 25, and is placed on the paper discharge tray 26 outside the apparatus.

  On the other hand, after the color image is transferred to the recording medium P by the secondary transfer roller 5A, the residual toner is removed by the cleaning means 6A from the endless belt-shaped intermediate transfer body 70 from which the recording medium P is separated by curvature.

  During the image forming process, the primary transfer roller 5K is always in pressure contact with the photoreceptor 1K. The other primary transfer rollers 5Y, 5M, and 5C are in pressure contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roller 5A comes into pressure contact with the endless belt-shaped intermediate transfer body 70 only when the recording medium P passes through the secondary transfer roller 5A and secondary transfer is performed.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R. The housing 8 includes image forming units 10Y, 10M, 10C, and 10K, and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10K are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer body unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1K in the figure. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rollers 71, 72, 73, 74, and 76, primary transfer rollers 5Y, 5M, 5C, and 5K, and a cleaning unit. 6A.

  The image forming units 10Y, 10M, 10C, and 10K and the endless belt-shaped intermediate transfer body unit 7 are integrally pulled out from the main body A by the drawer operation of the housing 8.

  In this manner, the outer peripheral surfaces of the photoreceptors 1Y, 1M, 1C, and 1K are charged and exposed to form a latent image on the outer peripheral surface, and then a toner image (developed image) is formed by development, and an endless belt-like intermediate transfer The toner images of the respective colors are superposed on the body 70, transferred to the recording medium P in a lump, and fixed and fixed by the fixing device 24 by pressure and heating. In the present invention, the time of image formation includes latent image formation and transfer of a toner image (developed image) to a recording medium P to form a final image.

  The photoreceptors 1Y, 1M, 1C, and 1K after transferring the toner image to the recording medium P clean the toner remaining on the photoreceptor during transfer by the cleaning unit 6A, and then perform the above charging, exposure, and development cycle. The next image formation is performed.

  In the color image forming apparatus, an elastic blade is used as a cleaning member of the cleaning unit 6A for cleaning the intermediate transfer member. Further, means (11Y, 11M, 11C, 11K) for applying a fatty acid metal salt to each photoconductor is provided. As the fatty acid metal salt, the same fatty acid metal salt as used in the toner can be used.

  In the present invention, when the toners 1Y, 1M, 1C, and 1K after the toner image is transferred to the recording medium P are cleaned by the blades of the cleaning units 6Y to 6K, Prevents wear on the surface of the photoreceptor due to contact with the surface, deteriorates electrical properties such as sensitivity deterioration and chargeability, prevents image density reduction, and abnormal images such as background stains. The present invention relates to a method for producing a durable electrophotographic photosensitive member that prevents images.

  FIG. 2 is a schematic perspective view of the photoreceptor shown in FIG. Since all of the photoconductors 1Y, 1M, 1C, and 1K shown in FIG. 1 have the same configuration, the photoconductor 1Y will be described as a representative.

  In the figure, 1Y represents a photoreceptor. The photoreceptor 1Y includes a cylindrical conductive substrate 1Y1, a photosensitive layer 1Y2 formed on the peripheral surface of the cylindrical conductive substrate 1Y1, a protective layer 1Y3 formed on the surface of the photosensitive layer 1Y2, and a cylindrical shape. A non-photosensitive layer forming portion 1Y4 is provided at both ends of the conductive substrate 1Y1, and attachment shafts 1Y5 to an electrophotographic image forming apparatus (not shown) are provided at both ends of the cylindrical conductive substrate 1Y1. Reference numeral 1Y51 denotes a drive hole for rotating the photosensitive member 1Y by engaging with a rotation shaft on the image forming device 1 (see FIG. 1) side when the photosensitive member 1Y is set in the image forming apparatus 1 (see FIG. 1). .

  The formation region of the photosensitive layer 1Y2 may be formed over the entire width of the cylindrical conductive substrate 1Y1, or may be formed leaving the non-photosensitive layer forming portions 1Y4 at both ends of the cylindrical conductive substrate 1Y1. It can be appropriately changed depending on the method of forming the photosensitive layer 1Y2. This figure shows a state in which the non-photosensitive layer forming portion 1Y3 is formed at both ends. The width of the non-photosensitive layer forming portion 1Y4 is preferably 0.5 mm to 20 mm.

  The photosensitive layer 1Y2 having the protective layer 1Y3 formed on the cylindrical conductive substrate 1Y1 is developed by the developing device 1 (see FIG. 1) to show an image forming area where a toner image is formed. This is an area where residual toner exists after the toner image is formed and transferred to the recording paper, and is also an area to be cleaned by bleed.

  FIG. 3 is a schematic cross-sectional view showing an example of the configuration of the photosensitive layer of the photoreceptor shown in FIG.

  This will be described with reference to (a). In the figure, 1Ya represents a photoreceptor. In the photoreceptor 1Ya, a charge generation layer (CGL) 1Ya2 is formed on the outer periphery of a cylindrical conductive substrate 1Ya1, and a charge transport layer (CTL) 1Ya3 is laminated thereon to form a photosensitive layer 1Ya5. CTL) A protective layer 1Ya4 is laminated on 1Ya3.

  This will be described with reference to (b). In the figure, 1Yb indicates a photoreceptor. In the photoreceptor 1Yb, a charge transport layer (CTL) 1Yb3 is formed on the outer periphery of a cylindrical conductive substrate 1Yb1, a charge generation layer (CGL) 1Yb2 is laminated thereon, a photosensitive layer 1Yb5 is formed, and a charge generation layer ( CGL) A protective layer 1Yb4 is laminated on 1Yb2.

  This will be described with reference to (c). In the figure, 1Yc represents a photoreceptor. In the photoreceptor 1Yc, an intermediate layer 1Yc6 is provided on the outer periphery of a cylindrical conductive substrate 1Yc1, a charge generation layer (CGL) 1Yc2 is formed thereon, and a charge transport layer (CTL) 1Yc3 is laminated thereon to form a photosensitive layer 1Yc5. And a protective layer 1Yc4 is stacked on the charge transport layer 1Yc3.

  This will be described with reference to (d). In the figure, 1Yd indicates a photoconductor. In the photoreceptor 1Yd, an intermediate layer 1Yd6 is provided on the outer periphery of a cylindrical conductive substrate 1Yd1, a charge transport layer (CTL) 1Yd3 is formed thereon, and a charge generation layer (CGL) 1Yd2 is laminated thereon to form a photosensitive layer 1Yd5. And a protective layer 1Yd4 is stacked on the charge generation layer (CGL) 1Yd2.

  This will be described with reference to (e). In the figure, 1Ye indicates a photoreceptor. The photoreceptor 1Ye is formed by laminating a layer containing a charge generating material 1Ye7 and a charge transporting material 1Ye8 on the outer periphery of a cylindrical conductive substrate 1Ye1 to form a photosensitive layer 1Ye5, and containing the charge generating material 1Ye7 and the charge transporting material 1Ye8. The protective layer 1Ye4 is laminated on the layer.

  This will be described with reference to (f). In the figure, 1Yf represents a photoreceptor. In the photoreceptor 1Yf, an intermediate layer 1Yf6 is provided on the outer periphery of a cylindrical conductive substrate 1Yf1, and a layer containing a charge generating material 1Yf7 and a charge transporting material 1Yf8 is laminated thereon to form a photosensitive layer 1Yf5. A protective layer 1Yf4 is formed on a layer containing 1Yf7 and a charge transport material 1Yf8.

  The structure of the photoconductor according to the method for producing the photoconductor of the present invention may be any of the structures shown in FIGS. 3A to 3F, and these photoconductors include the full-color image forming apparatus shown in FIG. It can be used in an image forming apparatus.

  3A to 3F each show a case where a protective layer is provided as a surface layer, the protective layer can be provided as necessary.

  The present invention relates to a method for producing a photoconductor having improved durability by making the surface roughness of the surface layer of the photoconductor shown in FIGS. 1 to 3 uniform. The surface layer of the photoconductor means a layer laminated on the surface of the charge transport layer (CTL) and the charge generation layer (CGL) in the photoconductor shown in FIGS.

  FIG. 4 is a schematic view showing a method for producing a photoreceptor having an uneven surface layer on the surface using an ink jet unit. FIG. 4A is a schematic perspective view showing a method for producing a photoreceptor having an uneven surface layer on the surface of the photosensitive layer using an inkjet unit. FIG. 4B is a schematic plan view of FIG.

  In the figure, reference numeral 2 denotes an ink jet unit, an ink jet head 201 for spraying a surface layer forming coating liquid onto the surface of the cylindrical conductive substrate 3, and a supply pipe 202 for supplying the surface layer forming coating liquid to the ink jet head 201. have.

  The surface of the cylindrical conductive substrate 3 is the surface of the photosensitive layer in which the layers other than the protective layer are already formed in the structure of the photosensitive member shown in FIGS. Each layer already formed to form each lower layer and the surface of the cylindrical conductive substrate 3 are said.

  In the case of the structure of the photoreceptor shown in FIGS. 3A to 3F, the surface layer forming coating solution is a protective layer forming coating solution, a charge transport layer (CTL) forming coating solution, and a charge generation layer (CGL). And a coating solution for forming a layer containing a charge generating substance and a charge transporting substance.

  The solid content concentration of the coating solution for forming the surface layer is preferably higher in order to increase the height when the droplet ejected from the inkjet head 201 is cured on the surface of the cylindrical conductive substrate 3. .

  For example, in the case of a coating liquid for forming a protective layer, the content is preferably 10% by mass to 50% by mass. The coating solution for forming the charge transport layer (CTL) is preferably 10% by mass to 50% by mass. The coating solution for forming the charge generation layer (CGL) is preferably 2% by mass to 5% by mass. The coating liquid for layer formation containing the charge generation material and the charge transport material is preferably 10% by mass to 50% by mass.

  The viscosity of the coating solution for forming the surface layer is 4 mPa in order to prevent leveling of the liquid droplets ejected from the inkjet head 201 and landing on the surface of the cylindrical conductive substrate 3 and to increase the height when cured. · S to 100 mPa · s is preferable.

  The solvent used for the preparation of the surface layer forming coating solution is preferably a solvent having a boiling point of 90 ° C. to 200 ° C. in consideration of drying of the head, residual solvent, and the like. In the case of a mixed solvent system, the boiling point of the solvent having a high boiling point is preferably 90 ° C. to 200 ° C.

  The inkjet unit 2 is attached to a guide rail (not shown) via an attachment member (not shown), and can be moved in the direction of the rotation axis of the photoreceptor 2 in parallel with the surface of the photosensitive layer by a motor (not shown) ( They are arranged so as to be in the direction of arrow A in the figure.

  The inkjet head 201 is not particularly limited, and examples thereof include a continuous type and an intermittent type (piezo, thermal, electrostatic type, etc.). Of these, a continuous type and an intermittent type using a piezo are preferable, and an intermittent type using a piezo is more preferable.

  The inkjet head 201 preferably has an inkjet head cleaning function in case the inkjet head 201 is solidified or clogged by drying the surface layer forming coating solution. Examples of the inkjet head cleaning function include a function of cleaning with an organic solvent used in the coating liquid, and a function of suction. Reference numeral 4 denotes a curing unit that cures droplets of the surface layer forming coating solution landed on the surface of the photosensitive layer by the inkjet head 201.

  The curing means 4 is attached to a guide rail (not shown) via an attachment member (not shown), and a cylindrical conductive substrate parallel to the surface of the cylindrical conductive substrate 3 by a motor (not shown). 3 is arranged to be movable in the direction of the rotation axis 3 (in the direction of arrow B in the figure).

  The curing means 4 needs to be set according to the binder resin used in the surface layer forming coating solution. When the resin is an active energy ray curable resin, it is an active energy ray irradiation device, and when the resin is a thermosetting resin, it is a heat application device.

A known device can be used as the active energy ray irradiation device. As a light source for curing the ultraviolet curable resin by a photocuring reaction, any light source that generates ultraviolet light can be used without limitation. For example, an LED, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used. The irradiation conditions vary depending on individual lamps, but the amount of light irradiated may if 10000 mJ / cm ² degree from 20 mJ / cm ^2, is preferably a 2000 mJ / cm ² from 50 mJ / cm ^2. In the near-ultraviolet region to the visible light region, it can be efficiently formed by using a sensitizer having an absorption maximum in that region.

  The heat application device is not particularly limited, but it is preferable to use a method in which hot air is continuously blown onto the surface of the landed droplets of the surface layer forming coating solution by an infrared heater. The heating temperature cannot be generally specified depending on the type of thermosetting resin to be used, but is preferably in a temperature range that does not affect the lower layer, preferably from 30 ° C to 200 ° C, and more preferably from 50 ° C to 150 ° C. ° C is preferred, particularly preferably 90 ° C to 120 ° C.

  The curing means 4 needs to move so as to follow the inkjet unit 2 in order to cure the droplets of the surface layer forming coating solution landed on the surface of the photosensitive layer by the inkjet unit 2. A specific movement will be described with reference to FIG.

  The ejection of the surface layer forming coating solution onto the surface of the cylindrical conductive substrate 3 by the inkjet head 201 is started from the position of the end 3 a of the cylindrical conductive substrate 3. At this time, the curing means 4 is disposed behind the ink jet head 201 (a position away from the end 3a), or is disposed at the same position as the ink jet head 201 with the function stopped.

  After the ejection of the surface layer forming coating liquid onto the surface of the cylindrical conductive substrate 3 by the ink jet head 201 is started, the curing means 4 applies the surface of the cylindrical conductive substrate 3 to which the surface layer forming coating liquid has landed. Operates to move to the spot and cure the landed droplets. Thereafter, as the ink jet head 201 moves to the end portion 3b of the cylindrical conductive substrate 3 while jetting the surface layer forming coating solution, the curing means 4 also moves following the ink jet head 201.

  After the droplets that have landed to the end 3b of the cylindrical conductive substrate 3 are cured, the inkjet head 201 moves while ejecting the surface layer forming coating liquid from the end 3b toward the end 3a. The curing means 4 also moves following the inkjet head 201. By repeating such an operation, the droplet of the coating liquid for forming the surface layer lands on the cured droplet, thereby forming a surface layer having an uneven shape on the surface of the cylindrical conductive substrate 3. It becomes possible.

  The cylindrical conductive substrate 3 is pivotally supported by a frame (not shown) of an apparatus (not shown) so as to be rotatable (in the direction of arrow C in the figure). Further, the cylindrical conductive substrate 3 may be disposed so as to be movable in the direction of the rotation axis of the cylindrical conductive substrate 3 (direction of arrow D in the figure).

  As a method for forming a surface layer having a concavo-convex shape on the surface of the cylindrical conductive substrate 3 using the ink jet unit 2 with reference to FIG. 4, there are a continuous method and an intermittent method. In the present invention, the surface layer may have a uniform layer structure or a non-uniform (discontinuous) structure by landing the surface layer forming coating liquid.

  In the case of the continuous method, the following method is possible.

  1. The position of the cylindrical conductive substrate 3 is fixed, and the inkjet unit 2 and the curing means 4 are continuously moved while rotating to form a surface layer having irregularities on the surface of the cylindrical conductive substrate 3. To do.

  2. The inkjet unit 2 and the curing means 4 are fixed, and the cylindrical conductive substrate 3 is continuously moved while rotating to form a surface layer having irregularities on the surface of the cylindrical conductive substrate 3.

  In the case of the intermittent method, the positions of the cylindrical conductive substrate 3, the inkjet unit 2 and the curing means 4 are fixed, and the cylindrical conductive substrate 3 is rotated once to form a surface layer on the peripheral surface of the cylindrical conductive substrate 3. Form. Thereafter, either the inkjet unit 2 and the curing means 4 or the cylindrical conductive substrate 3 is moved to form a surface layer on the surface of the cylindrical conductive substrate 3.

  FIG. 5 is a schematic plan view showing another example of the arrangement of the inkjet head shown in FIG.

  (A) has shown the case where the inkjet head 201 is inclined and arrange | positioned with respect to the rotating shaft of the cylindrical conductive base | substrate 3. FIG. The arrangement angle can be appropriately selected according to the interval between droplets that land on the surface of the cylindrical conductive substrate 3. Of course, a plurality of inkjet heads 201 may be arranged to be inclined with respect to the rotation axis of the cylindrical conductive substrate 3 as shown in FIG.

  FIG. 6B shows a case where a plurality of inkjet heads 201 are arranged in a zigzag shape parallel to the rotation axis of the cylindrical conductive substrate 3.

  (C) has shown the case where the line-shaped inkjet head match | combined with the length of the cylindrical electroconductive base | substrate 3 is used. In this case, since the droplets of the surface layer forming coating liquid land on the entire surface of the cylindrical conductive substrate 3 at a time, it is preferable that the curing means 4 is also matched to the width of the line-shaped inkjet head.

  6 is a schematic enlarged plan view of a portion indicated by P in FIG.

  In the figure, reference numeral 5 denotes a droplet in which the surface layer forming coating liquid sprayed from the ink jet unit 2 has landed on the surface of the cylindrical conductive substrate 3.

  T indicates the diameter of the droplet 5 after curing. The diameter T indicates the horizontal ferret diameter. The horizontal ferret diameter can be obtained by analyzing an image taken with a thermal field emission scanning electron microscope (manufactured by JEOL Ltd.) JSM-7600F with a high speed color image / analyzer (Nippon Avionics Co., Ltd.) SPICCA. Is possible.

  U indicates the interval between adjacent droplets 5. The interval U is preferably 1.5 times to 3.0 times the diameter T in consideration of leveling associated with contact between the droplets, stabilization of the shape when the droplets are cured, overlapping, and the like.

  FIG. 7 is a schematic flow diagram for forming a surface layer having an uneven shape on the surface of a cylindrical conductive substrate by the method of the present invention. The right cross-sectional view is a schematic cross-sectional view taken along the line WW ′ of the left view.

  On the surface of the cylindrical conductive substrate 3, a surface layer having an uneven shape is formed through the processes (a) to (f). In this figure, the curing unit 4 (see FIG. 4) is disposed downstream of the inkjet unit 2 (see FIG. 4), and the position of the cylindrical conductive substrate 3 is fixed and rotated while the inkjet unit 2 is rotated. 2 (see FIG. 4) is moved in the direction of the axis of rotation of the cylindrical conductive substrate 3, and a coating liquid for forming a surface layer is ejected to cause droplets to land on the surface of the cylindrical conductive substrate 3. Subsequently, the landed droplets are cured by the curing means 4 (see FIG. 4) to form a convex object. Thereafter, the liquid droplets of the surface layer forming coating liquid are landed on the convex object so that they do not come into contact with the adjacent liquid droplets by an inkjet head, and subsequently subjected to a curing treatment and a plurality of cured liquids The flow in the case of forming the surface layer which has the convex structure where the droplet was superimposed is shown. In the present invention, a surface layer having a superimposed convex structure is referred to as a surface layer having an uneven shape.

  (A) shows the state in which the coating liquid for forming the surface layer was ejected and landed on the surface of the cylindrical conductive substrate 3 from the inkjet head 201 for the first time. The portion painted in black indicates the portion of the surface of the cylindrical conductive substrate 3 where the surface layer forming coating solution has not landed. As a condition for ejecting the surface layer forming coating liquid from the inkjet head 201, it is necessary that the landed droplets 5 do not come into contact with each other as shown in FIG. By doing so, it is possible to prevent the droplets from fusing together and make the landed droplets 5 have a uniform shape.

  After the surface layer forming coating liquid has landed on the surface of the cylindrical conductive substrate 3, the curing process is performed by the curing means 4 (see FIG. 4), and the liquid droplets are cured and become convex.

  The process shown in (a) is a "process for forming a convex object by landing on the surface of the electrophotographic photosensitive member so that the liquid droplets of the present invention do not come into contact with adjacent liquid droplets".

  (B) shows the state in which the coating liquid for forming the surface layer was ejected from the second inkjet head 201 and landed between the droplets shown in (a). Thereafter, a curing process is performed by the curing means 4 (see FIG. 4), and the droplets are cured to become convex.

  (C) to (f) show the surface of the cylindrical conductive substrate 3 in which the coating liquid for forming the surface layer is ejected from the ink jet head 201 and repeatedly hits and cures, and the shaded portions are sequentially filled. Shows a process of forming a surface layer having a convex structure in which a droplet of a coating liquid for forming a surface layer is landed by an inkjet head so that it does not come into contact with adjacent droplets, and is cured. ing.

  The steps shown in (b) to (c) are “after that, the droplet of the coating liquid for forming the surface layer is landed on the convex material so as not to come into contact with the adjacent droplet. , A step of forming a surface layer having a convex structure in which a convex is superimposed by curing.

The features of the present invention are as shown in (a) to (f),
1) The ejection liquid of the surface layer forming coating liquid from the inkjet head 201 to the surface of the cylindrical conductive substrate 3 should be prevented from coming into contact with the landing droplet 2) To the surface of the cylindrical conductive substrate 3 The landed droplets are cured by the curing means. 3) After the droplets are cured, the adjacent droplets that land on the surface of the cylindrical conductive substrate 3 of the coating liquid for forming the surface layer from the inkjet head 201 come into contact again. 4) Repeating steps 1) to 3) repeatedly superimposing the convex objects on the convex objects formed by curing the droplets. In this way, a surface layer having an uneven shape is formed.

  The 10-point average surface roughness Rz of the surface layer having an uneven shape is preferably 0.1 μm to 3.0 μm in consideration of blade curl, cleaning properties, toner remaining, blade adhesion, and the like.

  The surface roughness indicates a value measured with SURFCOM 1400D manufactured by Tokyo Seimitsu Co., Ltd.

The following effects can be obtained by the method for producing a photoreceptor of the present invention.
1. It becomes easy to stabilize the uneven shape of the surface layer of the surface layer forming the photoreceptor, and it is possible to produce a photoreceptor having a surface layer having a uniform uneven shape.
2. As the surface irregularities are made uniform, it is possible to obtain the sliding property of the blade that can cope with the higher speed.
3. The cleaning property of the photoreceptor surface was improved and the image quality was stabilized.
4). Improved blade adhesion over time and improved initial torque change.

  As an example of a photoreceptor relating to the method for producing an electrophotographic photoreceptor of the present invention, an intermediate layer is provided on the outer periphery of a conductive support, and a charge generation layer, a charge transport layer, and a protective layer containing a filler are provided thereon. The material used for the photoconductor having the provided layer structure will be described.

<Conductive support>
A cylindrical support is used as the conductive support. The cylindrical conductive support means a cylindrical support necessary to be able to form an endless image by rotating, and the cylindricity is preferably 5 μm to 40 μm, more preferably 7 μm to 30 μm.

As a material for the conductive support, a metal drum such as aluminum or nickel, a plastic drum deposited with aluminum, tin oxide, indium oxide, or the like, or a paper / plastic drum coated with a conductive substance can be used. The conductive support preferably has a specific resistance of 10 ³ Ω · cm or less at room temperature.

<Intermediate layer>
The intermediate layer is formed by applying and drying an intermediate layer-forming coating liquid composed of a binder, a dispersion solvent, and the like on a conductive support. Examples of the binder for the intermediate layer include polyamide resins, vinyl chloride resins, vinyl acetate resins, and copolymer resins containing two or more of these resin repeating units. Among these resins, a polyamide resin is preferable because it can reduce an increase in residual potential due to repeated use. In addition, for the purpose of improving potential characteristics, reducing black spot defects, reducing moire, etc., additives such as fillers and antioxidants such as titanium oxide and zinc oxide can be added to the intermediate layer as necessary. .

  As the solvent for preparing the coating solution for forming the intermediate layer, a solvent in which inorganic particles to be added as needed are well dispersed and the polyamide resin is dissolved is preferable. Specifically, alcohols having 2 to 4 carbon atoms such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol and sec-butanol are excellent in solubility and coating performance of polyamide resin. preferable. These solvents are preferably 30% by mass to 100% by mass, preferably 40% by mass to 100% by mass, and more preferably 50% by mass to 100% by mass in the total solvent. Examples of co-solvents that can be used in combination with the above-mentioned solvent to obtain preferable effects include benzyl alcohol, toluene, methylene chloride, cyclohexanone, and tetrahydrofuran. The film thickness of the intermediate layer is preferably 0.2 μm to 40 μm, and more preferably 0.3 μm to 20 μm.

(Photosensitive layer)
The photosensitive layer may have a single layer structure in which a charge generation function and a charge transport function are provided in one layer, but more preferably the function of the photosensitive layer is separated into a charge generation layer (CGL) and a charge transport layer (CTL). It is more preferable to take a layer structure. By adopting a configuration in which the functions are separated, it is possible to control an increase in residual potential due to repeated use, and to easily control other electrophotographic characteristics according to the purpose.

  In the negatively charged photoreceptor, a charge generation layer (CGL) is formed on the intermediate layer, and a charge transport layer (CTL) is formed thereon. In the positively charged photoreceptor, the order of the layer configuration is opposite to that in the negatively charged photoreceptor. A preferred layer structure of the photosensitive layer is a negatively charged photoreceptor having the function separation structure.

  Hereinafter, each layer of the photosensitive layer of the function-separated negatively charged photoreceptor will be described.

<Charge generation layer (CGL)>
The charge generation layer (CGL) contains a charge generation material (CGM). As other substances, a binder resin and other additives may be contained as necessary. As the charge generation material (CGM), oxytitanium phthalocyanine having a maximum diffraction peak at a Bragg angle (2θ ± 0.2) of 27.2 ° in X-ray diffraction by CuKα ray, which is a known charge generation material (CGM), 2θ However, CGM such as benzimidazole perylene, which has a maximum peak at 12.4 °, is hardly deteriorated by repeated use, and the increase in residual potential can be reduced.

  When a binder is used as a dispersion medium for the charge generation material (CGM) in the charge generation layer (CGL), a known resin can be used as the binder, but the most preferable resins are formal resin, butyral resin, silicone resin, silicone. Examples include modified butyral resins and phenoxy resins. The ratio of the binder resin to the charge generating material (CGM) is preferably 20 to 600 parts by mass of the charge generating material (CGM) with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential associated with repeated use can be minimized. The film thickness of the charge generation layer (CGL) is preferably 0.01 μm to 2 μm.

<Charge transport layer (CTL)>
The charge transport layer (CTL) contains a charge transport material (CTM) and a binder resin. Other substances may be formed by adding additives such as antioxidants as necessary. The film thickness of CTL is preferably 5 μm to 40 μm, more preferably 10 μm to 30 μm. When the CTL forms a surface layer, the amount of filler in the CTL is preferably 5% by mass to 50% by mass.

  A known charge transport material (CTM) can be used as the charge transport material (CTM). For example, triphenylamine derivatives, hydrazone compounds, styryl compounds, benzidine compounds, butadiene compounds, and the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer.

  Examples of the resin used for the charge transport layer (CTL) include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, and polycarbonate. Resin, silicone resin, melamine resin, and copolymer resin containing two or more of the repeating units of these resins. In addition to these insulating resins, high molecular organic semiconductors such as poly-N-vinylcarbazole can be used.

  The most preferable binder for the charge transport layer (CTL) is a polycarbonate resin. The polycarbonate resin is most preferable in improving the dispersibility and electrophotographic characteristics of the charge transport material (CTM). The ratio of the binder resin to the charge transport material (CTM) is preferably 10 parts by mass to 200 parts by mass with respect to 100 parts by mass of the binder resin.

〔Antioxidant〕
When an antioxidant is applied to the constituent layers of the photoconductor, the influence of attack of an active gas such as NOx can be reduced, so that occurrence of image flow in a high temperature and high humidity environment can be suppressed.

  The typical antioxidant used in the present invention is to prevent the action of oxygen on auto-oxidizing substances existing in the photoreceptor or on the photoreceptor surface under conditions of light, heat, discharge, etc. It is also a substance having a suppressing property. Specifically, the following compound groups can be mentioned.

(1) Radical chain inhibitor Phenolic antioxidants, hindered phenolic antioxidants, amine antioxidants, hindered amine antioxidants, diallyldiamine antioxidants, diallylamine antioxidants, hydroquinone antioxidants Agents and the like.

(2) Peroxide decomposing agent Sulfur-based antioxidants, thioethers, phosphoric acid-based antioxidants, phosphites and the like can be mentioned.

  The hindered phenol antioxidant (antioxidant having a hindered phenol structure) is a compound having a bulky organic group at the ortho position of the phenolic OH group or the alkoxylated group of the phenolic OH. A system antioxidant (an antioxidant having a hindered amine structure) is a compound having a bulky organic group near the N atom. The bulky organic group includes a branched alkyl group, for example, a t-butyl group is preferable.

  Among the above antioxidants, the radical chain inhibitor (1) is good, and among them, the antioxidant having a hindered phenol structure or a hindered amine structure reacts with the radical active species generated from the polymerization initiator and oxygen. In order to prevent this, the generated radical active species can be effectively contributed to the reaction, which is preferable.

  Two or more types may be used in combination, for example, a combination of (1) a hindered phenol antioxidant and (2) a thioether antioxidant.

  In the antioxidant used in the present invention, more preferable is that the hindered amine structure in the molecule is good for image quality improvement such as image blur prevention and black spot countermeasures, and as another aspect, a hindered phenol structural unit. Those having hindered amine structural units in the molecule are also preferred.

Protective layer In addition to the binder resin, those having various compositions can be used. For example, those formed by adding fillers made of inorganic fine particles such as silica and alumina and organic fine particles such as PTFE and acrylic resin to the surface layer are preferable. The amount of the filler in the protective layer is preferably 5% by mass to 50% by mass.

(Resin as binder used to prepare coating solution for surface layer formation)
The resin as the binder is preferably an active energy ray curable resin or a thermosetting resin, and an active energy ray curable resin is particularly preferred from the viewpoint of handling.

(Active energy ray curable resin)
The active energy ray-curable resin used in the present invention is a resin that is cured through a crosslinking reaction or the like by irradiation with actinic rays such as ultraviolet rays and electron beams. Typical examples of the active energy ray curable resin include an ultraviolet curable resin and an electron beam curable resin, but a resin curable by irradiation with actinic rays other than ultraviolet rays and electron beams may be used.

  The active energy ray-curable resin is a resin obtained by curing a prepolymer, an oligomer and / or a monomer having a polymerizable unsaturated bond or an epoxy group in a molecule upon irradiation with energy rays.

  There is no restriction | limiting in particular as an ultraviolet-ray and an electron beam curable resin, It can use suitably selecting from what is used conventionally. This ultraviolet curable resin contains a photopolymerizable prepolymer, a photopolymerizable monomer, a photopolymerization initiator or a photosensitizer. The electron beam curable resin contains a photopolymerizable prepolymer or a photopolymerizable monomer.

  Examples of the photopolymerizable prepolymer include polyester acrylate, epoxy acrylate, urethane acrylate, and polyol acrylate. These photopolymerizable prepolymers may be used alone or in combination of two or more. Examples of the photopolymerizable monomer include polymethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, Examples include dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and neopentyl glycol di (meth) acrylate.

  Specific examples of the ultraviolet curable resin include, for example, ADEKA OPTMER KR, BY series KR-400, KR-410, KR-550, KR-566, KR-567, BY-320B (above, ADEKA Corporation) Manufactured by Koeihard Co., Ltd., A-101-KK, A-101-WS, C-302, C-401-N, C-501, M-101, M-102, T-102, D-102, NS- 101, FT-102Q8, MAG-1-P20, AG-106, M-101-C (manufactured by Guangei Chemical Industry Co., Ltd.), Seika Beam PHC2210 (S), PHCX-9 (K-3), PHC2213 , DP-10, DP-20, DP-30, P1000, P1100, P1200, P1300, P1400, P1500, P1600, SCR900 (above, Dainichi Manufactured by Kogyo Co., Ltd.), KRM7033, KRM7039, KRM7130, KRM7131, UVECRYL29201, UVECRYL29202 (above, Daicel UCB), RC-5015, RC-5016, RC-5020, RC-5031, RC-5100, RC-5102, RC-5120, RC-5122, RC-5152, RC-5171, RC-5180, RC-5181 (manufactured by DIC Corporation), Aulex No. 340 clear (manufactured by China Paint Co., Ltd.), Sun Rad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC-612 (above, Sanyo Chemical Industries, Ltd.) , SP-1509, SP-1507 (above, manufactured by Showa Polymer Co., Ltd.), RCC-15C (produced by Grace Japan Co., Ltd.), Aronix M-6100, M-8030, M-8060 (above, Toagosei Co., Ltd.) (Made by Co., Ltd.), or other commercially available products.

(Polymerization initiator)
The polymerization initiator may be a radical reaction type or an ion reaction type, and examples thereof include acetophenones, butylphenones, benzophenones, α-amyloxime esters, tetramethylchuram monosulfide, thioxanthones, and oxetane compounds. Moreover, n-butylamine, triethylamine, poly-n-butylphosphine, etc. can be mixed and used as a photosensitizer.

(Thermosetting resin)
Examples of the thermosetting resin that can be used in the present invention include unsaturated polyester resins, epoxy resins, vinyl ester resins, phenol resins, thermosetting polyimide resins, thermosetting polyamide imides, and the like.

As the unsaturated polyester resin, for example, orthophthalic acid resin, isophthalic acid resin, terephthalic acid resin, bisphenol resin, propylene glycol-maleic acid resin, dicyclopentadiene or derivatives thereof are introduced into the unsaturated polyester composition. Low styrene volatile resin with low molecular weight or added film-forming wax compound, low shrinkage with thermoplastic resin (polyvinyl acetate resin, styrene / butadiene copolymer, polystyrene, saturated polyester, etc.) Resin, unsaturated polyester brominated directly with Br ₂ or reactive type such as copolymerization of het acid, dibromoneopentyl glycol, halides such as chlorinated paraffin, tetrabromobisphenol and antimony trioxide, phosphorus Compound combinations Additive-type flame retardant resin that uses additives and aluminum hydroxide as additives, and toughness resins that are hybridized with polyurethane or silicone, or IPN toughness (high strength, high elastic modulus, high elongation), etc. is there.

  Examples of the epoxy resin include glycidyl ether type epoxy resins including bisphenol A type, novolak phenol type, bisphenol F type, brominated bisphenol A type, glycidyl amine type, glycidyl ester type, cyclic aliphatic type, and heterocyclic epoxy type. Special epoxy resins containing

  As the vinyl ester resin, for example, an oligomer obtained by ring-opening addition reaction of an ordinary epoxy resin and an unsaturated monobasic acid such as methacrylic acid is dissolved in a monomer such as styrene. There are also special types such as vinyl monomers having vinyl groups at the molecular ends and side chains. Examples of vinyl ester resins of glycidyl ether type epoxy resins include bisphenol type, novolak type, brominated bisphenol type, etc., and special vinyl ester resins include vinyl ester urethane type, isocyanuric acid vinyl type, side chain vinyl ester type, etc. There is.

  The phenol resin is obtained by polycondensation using phenols and formaldehyde as raw materials, and there are a resol type and a novolac type.

  Examples of thermosetting polyimide resins include maleic acid-based polyimides such as polymaleimide amine, polyamino bismaleimide, bismaleimide / O, O'-diallyl bisphenol-A resin, bismaleimide / triazine resin, and nadic acid-modified polyimide. And acetylene-terminated polyimide.

  A part of the actinic ray curable resin described above can also be used as a thermosetting resin.

  In addition, you may use antioxidant and a ultraviolet absorber suitably for the coating liquid for surface layer formation which consists of a thermosetting resin which concerns on this invention.

  The protective layer is formed by applying a coating solution prepared by adding at least inorganic fine particles to a binder resin on the charge transport layer. The protective layer preferably contains an antioxidant, a lubricant material, or the like.

  Inorganic fine particles include silica, alumina, strontium titanate, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, indium oxide doped with tin, tin oxide doped with antimony and tantalum, zirconium oxide, etc. These fine particles can be preferably used. In particular, silica, alumina, titanium oxide, strontium titanate and the like are preferable.

  The number average primary particle size of the inorganic fine particles is preferably 1 nm to 150 nm, particularly preferably 3 nm to 50 nm. The number average primary particle diameter of the inorganic fine particles is magnified 10,000 times by observation with a transmission electron microscope, 300 particles are randomly observed as primary particles, and the measured value is calculated as the number average diameter of the ferret diameter by image analysis. Is the value obtained.

  The binder resin used for the protective layer may be either a thermoplastic resin or a thermosetting resin. For example, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, and the like can be given.

  Lubricating substances used in the protective layer include resin fine powder (for example, fluorine resin, polyolefin resin, silicone resin, melamine resin, urea resin, acrylic resin, styrene resin, etc.), metal oxide fine powder (for example, Titanium oxide, aluminum oxide, tin oxide, etc.), solid lubricant (eg, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, zinc stearate, aluminum stearate, etc.), silicone oil (eg, dimethyl silicone oil) , Methyl phenyl silicone oil, methyl hydrogen polysiloxane, cyclic dimethyl polysiloxane, alkyl modified silicone oil, polyether modified silicone oil, alcohol modified silicone oil, fluorine modified silicone oil, amino modified silicone Oil, mercapto-modified silicone oil, epoxy-modified silicone oil, carboxyl-modified silicone oil, higher fatty acid-modified silicone oil, etc.), fluorine-based resin powder (for example, tetrafluoroethylene resin powder, trifluoroethylene chloride resin powder, Hexafluoroethylene propylene resin powder, vinyl fluoride resin powder, vinylidene fluoride resin powder, fluorinated ethylene chloride resin powder and copolymers thereof, polyolefin resin powder (for example, polyethylene resin) Homopolymer resin powder such as powder, polypropylene resin powder, polybutene resin powder, polyhexene resin powder, copolymer resin powder such as ethylene-propylene copolymer, ethylene-butene copolymer, and hexene Polyolefins such as terpolymers and these thermally modified products. Emissions-based resin powder and the like) and the like. In particular, silicone oil is preferable because it has a large friction coefficient reducing effect.

  The molecular weight of each resin used in the lubricant and the particle size of the powder can be appropriately selected. In the case of a particulate material, the particle size is particularly preferably 1 nm to 150 nm. In order to disperse these lubricants uniformly, a dispersant may be added to the binder resin. The lubricating material can also be added to the charge transport layer when the charge transport layer is the outermost surface.

(Production of photoconductor)
Each layer other than the outermost surface layer of the photoconductor according to the method for producing the photoconductor of the present invention is prepared by dip coating, circular amount regulation type coating, or a combination of dip coating and round amount regulation type coating. Although it can produce, it is not limited to this. The dip coating method is described in detail in, for example, Japanese Patent Application Laid-Open No. 2006-7155, and the circular amount regulation type coating is described in detail in, for example, Japanese Patent Application Laid-Open No. 58-189061.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the following text, “part” means “part by mass”.

Example 1
(Preparation of cylindrical conductive substrate)
A cylindrical conductive substrate made of aluminum having a diameter of 30 mm and a length of 360 mm was prepared, and the surface of the cylindrical conductive substrate was cut so that the 10-point average surface roughness Rz was 1.5 μm. A conductive substrate was prepared. In addition, 10 points average surface roughness Rz shows the value measured according to JISB0601-2001 using SURFCOM1400D by Tokyo Seimitsu Co., Ltd. as a measuring device.

(Formation of intermediate layer)
(Preparation of coating solution for intermediate layer formation)
A dispersion having the following composition was diluted twice with the same mixed solvent, and allowed to stand overnight, followed by filtration (filter; using a lime mesh 5 μm filter manufactured by Nihon Pall Co., Ltd.) to prepare a coating solution for forming an intermediate layer.

Polyamide resin CM8000 (manufactured by Toray Industries, Inc.) 1 part Titanium oxide SMT500SAS (manufactured by Teika) 3 parts Methanol 8 parts 1-butanol 2 parts Dispersion was carried out for 10 hours in a batch mode using a sand mill as a disperser.

(Application of coating solution for intermediate layer formation)
On the cylindrical conductive substrate prepared using the prepared coating solution for forming an intermediate layer, it was applied by dip coating and dried at 100 ° C. for 20 minutes to form an intermediate layer having a dry film thickness of 2 μm.

(Formation of charge generation layer)
(Preparation of coating solution for charge generation layer formation)
Charge generation material: titanyl phthalocyanine pigment (titanyl phthalocyanine pigment having a maximum diffraction peak at a position of at least 27.3 ± 0.2 ° as measured by Cu-Kα characteristic X-ray diffraction spectrum) 20 parts polyvinyl butyral resin (# 6000-C 10 parts t-butyl acetate 700 parts 4-methoxy-4-methyl-2-pentanone 300 parts are mixed and dispersed for 10 hours using a sand mill to prepare a coating solution for forming a charge generation layer. did.

(Application of coating solution for charge generation layer formation)
The prepared charge generation layer forming coating solution was applied onto the intermediate layer by a dip coating method to form a charge generation layer having a thickness of 0.3 μm after natural drying.

(Formation of charge transport layer)
(Preparation of coating solution for charge transport layer formation)
Charge transport material (4,4′-dimethyl-4 ″-(β-phenylstyryl) triphenylamine) 25 parts Binder: Polycarbonate (Z300: manufactured by Mitsubishi Gas Chemical) 300 parts Antioxidant (Irganox 1010: Ciba Japan) 6 parts) THF 1600 parts Toluene 400 parts Silicone oil (KF-50: manufactured by Shin-Etsu Chemical Co., Ltd.) 0.001 part was mixed and dissolved to prepare a coating solution for forming a charge transport layer.

(Application of coating liquid for charge transport layer formation)
The prepared coating solution for forming a charge transport layer was applied onto the charge generation layer by a dip coating method, dried at 110 ° C. for 70 minutes, and a charge transport layer having a dry film thickness of 25 μm was laminated to form a photosensitive layer.

(Formation of protective layer)
(Preparation of protective layer forming coating solution)
Titanium oxide particles (SMT100SAS: manufactured by Teica Co., Ltd.) 0.6 part 1-propanol 5 parts are mixed and dispersed for 1 hour with a US homogenizer. Thereafter, 1.5 parts of a radical polymerization compound composed of an acrylic compound A and an acrylic compound B (mass ratio 1/1) having the following structural formula and a polymerization initiator “Irgacure 184 (manufactured by Ciba Japan Co., Ltd.)” 0 0.07 parts is dissolved in the dispersion to prepare a coating solution for forming a protective layer.

  The viscosity of the protective layer-forming coating solution was 20 mPa · s. In addition, the measurement of a viscosity shows the value measured using the Toki Sangyo Co., Ltd. product R215 viscometer.

(Application of protective layer forming coating solution)
In the manufacturing method shown in FIG. 4, the prepared coating liquid for forming the protective layer is subjected to the process shown in FIG. 7 using a shear mode type (piezo type) ink jet head at a temperature of 25 ± 3 ° C. under the following conditions. Droplets are formed on the entire surface of the charge transport layer by changing the interval between the droplets and the number of landing / curing times as shown in Table 1 to form a protective layer having a concavo-convex shape and a thickness of 5 μm. A photoconductor having the structure shown in FIG. 101 to 108.

Ink jet head ejection conditions Landing droplet diameter: 20 μm
Nozzle outlet diameter: 10 μm
Pitch between nozzles: 100 μm
Number of nozzles: 200
Several methods of arrangement of ink jet heads: One was arranged in parallel with the rotation axis of the photoreceptor.

Inkjet head moving speed: 600 cm / min
Rotational speed (circumferential speed) of cylindrical conductive substrate laminated up to charge transport layer: 6 m / min
Curing conditions for landed droplets Using a mercury lamp irradiation device “ECS-401GX (made by Eye Graphics)” as an ultraviolet irradiation device, an ultraviolet integrated illuminance meter “UVPF-A1 (PD-365)” (made by Eye Graphics) ”Is irradiated with ultraviolet rays so that the integrated light quantity is equivalent to 25 J / cm ² .

Comparative photoreceptor No. No. 109 Sample No. A cylindrical conductive substrate in which up to the photosensitive layer was formed in the same manner as in 101 was used. A protective layer-forming coating film was formed by dip coating using the same protective layer-forming coating solution as 101. Thereafter, 1-propanol used for preparing the protective layer-forming coating solution was adjusted to a diameter of 25 μm while rotating the conductive substrate on which the protective layer-forming coating film was formed at a rotational speed (circumferential speed) of 6 m / min. After the droplets were sprayed on the entire peripheral surface with the spraying device, the sample No. The protective layer-forming coating film is cured by irradiating with ultraviolet rays in the same manner as in 101 to form a protective layer having an uneven shape. 109.

  As a spraying device, a small hand spray gun F100 manufactured by Meiji Machinery Co., Ltd. was used.

Evaluation The produced sample No. Table 2 shows the results of measurement according to the evaluation ranks shown below, measured according to the following methods for the sliding properties, cleaning properties, and image quality of the blades from 101 to 109.

Evaluation method of the sliding property of the blade As the sliding property of the blade, the 10-point average surface roughness Rz and the variation of the 10-point average surface roughness Rz (%) are measured. The substitute characteristics of the sliding property of the blade were used. The 10-point average surface roughness Rz and the 10-point average surface roughness Rz variation (%) of the protective layer of each sample obtained are shown together. The 10-point average surface roughness Rz of the protective layer is a value measured with SURFCOM 1400D manufactured by Tokyo Seimitsu Co., Ltd. The variation in the 10-point average surface roughness Rz is a value obtained by calculation from the following formula.

Variation in 10-point average surface roughness Rz (%) = ((maximum 10-point average surface roughness Rz−minimum 10-point average surface roughness Rz) / 10-point average surface roughness Rz) × 100
As 10-point average surface roughness Rz, the range of 0.4 μm or more and less than 3 μm does not affect the slipperiness, and the range of 0.1 μm or more and less than 0.4 μm has no practical problem, but slightly affects the slipperiness. The range, less than 0.1 μm, was set to affect the slipperiness.

  As the variation (%) of the 10-point average surface roughness Rz, a range where less than 10% does not affect the slipperiness is 10% or more, and less than 20% is practically no problem, but slightly affects the slipperiness. The range, 20% or more, is a range that affects slipperiness.

Test Method for Adhering Blades With the blades in contact with the photoreceptor, they were left at a temperature of 10 ° C. and a humidity of 20% RH for 24 hours, and the difference in torque before and after being left was measured. Torque was measured with a digital torque gauge / part number MD31TGE-10CNT.

Evaluation rank of blade sticking ◎: Less than 7N ○: 7N or more, less than 10N △: 10N or more, less than 15N ×: 15N or more Test method for turning the blade In the first to 20,000th copy, the blade turned The presence or absence was visually observed.

Test method for cleaning property The surface of the photoconductor was cleaned with a blade and the photoconductor was observed, and the presence or absence of toner adhesion was visually observed.

Evaluation rank of cleaning property ◎: No toner adhesion ○: Adhesion is rarely seen in the range that does not affect the image △: Adhesion is recognized in the range that does not affect the image ×: Adhesion is recognized in the range that affects the image Image quality test method For halftone images created at the same density on the entire surface, measure the density with a Macbeth densitometer manufactured by Gretag Macbeth Co., and calculate the difference (image unevenness) between the highest density and the lowest density to determine the quality of the image. Substitute characteristics were used. The measurement was performed while avoiding toner adhering matter generated due to poor cleaning.

Image quality evaluation rank ◎: Difference between maximum density and minimum density is less than 0.05 ○: Difference between maximum density and minimum density is less than 0.1 to 0.05 or more △: Difference between maximum density and minimum density Is less than 0.2 to 0.1 or more. X: The difference between the highest density and the lowest density is 0.2 or more.

  Sample No. prepared by the method of the present invention was used. 102 to 108 are comparative sample Nos. Compared to 101 and 109, blade slipperiness (10-point average surface roughness Rz, 10-point average surface roughness Rz variation (%), blade sticking, blade turning), cleaning properties, and image quality Also confirmed excellent results. Sample No. prepared with one landing / curing operation. 101 is the method of the present invention in terms of blade slipperiness (10-point average surface roughness Rz and 10-point average surface roughness Rz variation (%), blade sticking, blade turning), cleaning properties, and image quality. The prepared sample No. It was confirmed that any of the results from 102 to 108 showed inferior results. Sample No. prepared by a known method. 109 is a method of the present invention in terms of blade slipperiness (10-point average surface roughness Rz and 10-point average surface roughness Rz variation (%), blade sticking, blade turning), cleaning properties, and image quality. The prepared sample No. It was confirmed that any of the results from 102 to 108 showed inferior results. The effectiveness of the present invention was confirmed.

  As a thermosetting resin instead of an ultraviolet curable resin, 10 parts of thermosetting urethane prepolymer bandex P-910 (manufactured by DIC Corporation) and 100 parts of methyl ethyl ketone as a solvent were used to form a protective layer. Using the coating solution, sample no. A sample prepared by applying the same method as in No. 105 and curing at 130 ° C. ± 3 ° C. The same result as 105 was obtained.

Example 2
In the same manner as in Example 1, a cylindrical conductive substrate in which up to the photosensitive layer was laminated was prepared.

(Application of protective layer forming coating solution)
Sample No. 1 of Example 1 was formed on the entire surface of the charge transport layer of the cylindrical conductive substrate on which the photosensitive layer prepared through the process shown in FIG. The same ink jet head as that used for manufacturing 101 was used, and the same droplets of the coating liquid for forming the protective layer as in Example 1 were landed 20 times with a constant interval between the droplets, and the number of times of curing was adjusted. As shown in Table 3, a photoconductor having a structure shown in FIG. 201 to 207.

Evaluation The produced sample No. Table 4 shows the results of measurement according to the same evaluation rank as in Example 1 measured according to the same evaluation rank as in Example 1 for the slipperiness (blade sticking, turning of the blade) 201 to 207, and the cleaning performance and image quality. Shown in The variation (%) of the 10-point average surface roughness Rz of each obtained sample is shown together.

  When the surface layer is formed by ejecting the coating liquid for forming the surface layer with an inkjet head and landing on the surface of the cylindrical conductive substrate, the 10-point average surface roughness Rz of the surface layer (protective layer) is from 0.1 μm to 3 0.0μm, it was confirmed that the sliding performance of the blade (and the dispersion of the 10-point average surface roughness Rz (%) blade sticking, turning of the blade), cleaning properties and image quality were all excellent. did. The effectiveness of the present invention was confirmed.

Example 3
In the same manner as in Example 1, a cylindrical conductive substrate in which up to the photosensitive layer was laminated was prepared.

(Application of protective layer forming coating solution)
Sample No. 1 of Example 1 was formed on the entire surface of the charge transport layer of the cylindrical conductive substrate in which up to the photosensitive layer prepared through the process shown in FIG. Sample No. 1 of Example 1 was used except that the same ink jet head as that used to prepare 101 was used and the viscosity of the coating liquid for forming a protective layer having the same composition as Example 1 was changed as shown in Table 5. A photosensitive member having the structure shown in FIG. 3C was prepared by depositing and curing droplets under the same conditions as in 101 to form a protective layer. 301 to 306.

Evaluation The produced sample No. Sliding properties of blades from 301 to 306 (10-point average surface roughness Rz and 10-point average surface roughness Rz variation (%), blade sticking, blade turning) Examples relating to cleaning properties and image quality Table 5 shows the results of measurement according to the same method as in Example 1 and evaluation according to the same evaluation rank as Example 1. The 10-point average surface roughness Rz and the 10-point average surface roughness Rz variation (%) of the protective layer of each sample obtained are shown together.

  When the surface layer is formed by jetting the surface layer forming coating solution onto the surface of the cylindrical conductive substrate with an inkjet head, the viscosity of the surface layer forming coating solution should be in the range of 3 mPa · s to 200 mPa · s. Excellent results in blade slipperiness (10-point average surface roughness Rz, 10-point average surface roughness Rz variation (%), blade sticking, blade turning), cleaning properties, and image quality Confirmed to show. The effectiveness of the present invention was confirmed.

DESCRIPTION OF SYMBOLS 1 Full color image forming apparatus 1Y, 1Ya to 1Yf, 1M, 1C, 1K Photoconductor 1Ya1 to 1Yf1, 3 Cylindrical conductive substrate 1Ya2 to 1Yf2 Charge generation layer (CGL)
1Ya3 to 1Yd3 charge transport layer (CTL)
1Ya4 to 1Yf4 Protective layer 1Ya5 to 1Yf5 Photosensitive layer 1Yd6, 1Yf6 Intermediate layer 2 Inkjet unit 201 Inkjet head 4 Curing means 5 Droplet U interval T Diameter

Claims (6)

  An electrophotographic photosensitive member having a photosensitive layer on a cylindrical conductive substrate, and a surface layer forming coating solution is ejected onto the surface of the substrate using an ink jet head so that droplets are landed and cured to form a surface layer. In the body, the surface layer is a convex shape in which droplets of the coating liquid for forming the surface layer are landed and cured so that they do not contact each other and adjacent to each other, and a plurality of cured droplets are superimposed An electrophotographic photosensitive member having a structure. In the method for producing an electrophotographic photosensitive member in which a surface layer forming coating liquid is ejected onto the surface of a cylindrical conductive substrate by using an ink jet head, droplets are landed and cured to form a surface layer. A process for producing an electrophotographic photoreceptor, comprising a step.
1. The droplets land on the surface of the electrophotographic photosensitive member so that they do not come into contact with adjacent droplets,
1. Step of curing to form a convex object Thereafter, a surface layer having a convex structure in which a droplet of a coating liquid for forming a surface layer is landed on the convex so as not to come into contact with an adjacent droplet, and is cured and superimposed with the convex. Forming process   3. The distance between adjacent droplets that have landed on the surface of the cylindrical conductive substrate is 1.5 to 3.0 times the diameter of the droplets. A method for producing the electrophotographic photosensitive member according to the description.   The method for producing an electrophotographic photosensitive member according to claim 2, wherein the surface layer has a 10-point average surface roughness Rz of 0.1 μm to 3.0 μm.   5. The method for producing an electrophotographic photosensitive member according to claim 2, wherein the coating liquid for forming the surface layer has a viscosity of 3 mPa · s to 200 mPa · s.   6. The method for producing an electrophotographic photosensitive member according to claim 2, wherein the surface layer forming coating solution contains an actinic ray curable resin or a thermosetting resin.

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