JP2007171758A - Electrophotographic photoreceptor and method for manufacturing electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor in which a cleaning blade favorably exhibits its function even when the cleaning blade abuts up to the end of a coating film on the photoreceptor drum, that can maintain a favorable state of picture qualities, and that can increase the effective image region on a photosensitive layer surface. <P>SOLUTION: The electrophotographic photoreceptor comprises a cylindrical substrate having a coating film on the peripheral surface and having a coating film-removed portion in at least one end. In this photoreceptor, a height of the coating film within 2 mm in the coating film side from the boundary of removing the coating film between the coating film and the coating film-removed portion and the thickness of a residual coating film in the coating film-removed portion are controlled to predetermined ranges, so that a cleaning blade favorably exhibits its function even when the cleaning blade abuts up to the coating film end on the photoreceptor drum, to maintain a favorable state of picture qualities and increase an effective image area of a photosensitive layer surface in an image forming device such as a copying machine and a laser printer, particularly, a small-size image forming device. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member in which a coating film removing portion is formed on at least one end portion of a cylindrical substrate having a coating film applied by a dip coating method or the like, and a manufacturing method thereof.

  In an electrophotographic photoreceptor (hereinafter sometimes referred to simply as “photoreceptor”), an intermediate layer is provided on a conductive cylindrical substrate as necessary, and then a charge generation layer and a charge transport layer are formed. Is done. When such an electrophotographic photosensitive member is used in an image forming apparatus such as a copying machine or a laser printer, the distance between the electrophotographic photosensitive member and the developing roll must always be kept constant in order to maintain good development performance. I must. For this reason, usually, a method of applying a roller to both ends of the electrophotographic photosensitive member or holding it by coloring is employed. In that case, the portions where the rollers and the color ring at both ends of the electrophotographic photosensitive member are in contact with each other are rubbed, so that when a coating film such as a charge generation layer is present, the electrophotographic photosensitive member is peeled unevenly or worn out. There is a problem of doing. Therefore, it is necessary that no coating film is formed on that portion.

  As a method for producing an electrophotographic photosensitive member by forming a coating film such as a charge generation layer on a cylindrical substrate, a dip coating method in which a conductive cylindrical substrate is dipped in a coating solution for coating film coating. Is common. In this case, it is possible to easily prevent the coating film from being formed on the upper end portion of the cylindrical substrate by adjusting the immersion position of the cylindrical substrate to expose the upper end portion thereof. However, on the other hand, the lower end portion of the cylindrical substrate is immersed in the coating solution, so that a coating film is inevitably formed there. Therefore, the coating film formed on the lower end of the cylindrical substrate must be removed after the coating operation.

  Therefore, various methods for removing the coating film on the lower end portion of the electrophotographic photosensitive member have been proposed. Usually, the coating film is removed by mechanically wiping the lower end of the electrophotographic photosensitive member in the presence of a solvent. In such a chemical treatment using a solvent, solvent droplets, vapor, or the like may come into contact with a coating film in a region that is not intended to be removed, and the quality of the resulting photosensitive drum may be degraded. In addition, the initial cost of the solvent and the cost of removing the solvent become very expensive. Furthermore, when the coating film includes various layers of different materials, a solvent suitable for each of the various layers is required. This increases the complexity of solvent removal by coating, since each layer must be treated separately with a separate solvent. Furthermore, organic solvents have a limited useful life due to deterioration, contamination, and the like, and have problems in terms of work safety and environment. There is also a method of removing the coating film by mechanical means such as cutting or polishing, but it requires an operation with very high precision and is inefficient, and it may disturb the dimensional accuracy of the photosensitive drum. There is also.

  In recent years, in order to meet the needs for high precision and small size and light weight especially for copying machines and the like, there has been a demand for a more accurate processing method for the end of the photosensitive layer of the photosensitive drum. For example, Patent Document 1 describes a method of attempting to remove a coating film from an end portion of a photosensitive drum without using a mechanical or chemical treatment. In order to bake or sublimate the coating film on the photosensitive drum, the end of the photosensitive drum is irradiated with a laser beam from a YAG laser. Patent Document 2 also shows a similar method. Although these laser coating removal methods are intended to remove the coating completely, many of the materials commonly used for photoreceptor drum coatings do not evaporate. To melt. Therefore, in order to prevent the melted coating film from being deposited and cured as it is on the coating film removal portion, Patent Document 3 proposes a method of removing the molten coating film as dust fragments by accompanying a fluid simultaneously with laser irradiation. Has been.

JP-A-3-144458 JP-A-5-34934 JP 7-284964 A

  However, the removal of the coating film by laser irradiation as described in Patent Documents 1 to 3 inevitably generates burr-like raised protrusions in the vicinity of the boundary between the coating film removal portion and the coating film portion. There is a problem that the cleaning blade that comes in contact with the burr-like protrusions is turned over or turned up to break the cleaning blade or cause toner contamination. Further, even in the chemical treatment using the solvent, a raised protrusion is generated in the vicinity of the boundary between the coating film removal portion and the coating film portion, and the same problem occurs.

  Especially in small copying machines, printers, etc., there is a demand for the cleaning blade to come into contact with the coating film end of the photosensitive drum, and to increase the effective image area of the photosensitive layer surface. It is required to reduce the swelled portion in the vicinity of the boundary.

  The present invention provides an image forming apparatus such as a copying machine and a laser printer, particularly a small-sized image forming apparatus, in which even if the cleaning blade comes into contact with the coating film end of the photosensitive drum, the function of the cleaning blade can be exhibited well. An electrophotographic photosensitive member that can maintain a good state and can expand an effective image area on the surface of the photosensitive layer, and a method for producing the electrophotographic photosensitive member.

  The present invention is also a method for producing an electrophotographic photosensitive member capable of efficiently and accurately removing an end coating film of a photosensitive drum formed by a dip coating method or the like.

  The present invention relates to an electrophotographic photosensitive member in which a coating film removing portion is formed at least at one end of a cylindrical substrate having a coating film on an outer peripheral surface, the coating film removing boundary portion between the coating film and the coating film removing portion. To the coating film side, the rising height of the coating film within 2 mm is 10 μm or less, and the coating film residue thickness of the coating film removing part is 0.1 μm or less.

  The present invention also provides a method for producing an electrophotographic photosensitive member, wherein a coating film removing portion is formed on at least one end portion of a cylindrical substrate having a coating film coated on the outer peripheral surface by a dip coating method. By irradiating a laser while supplying a fluid to at least a part of the coating film removal target portion to be removed, the coating film removal portion is removed by removing the end coating film of the cylindrical substrate on which the coating film is formed. A coating film removal step to be formed, and in the coating film removal step, the coating film removal target portion is at least two of a region near the coating film removal boundary portion of the coating film and the coating film removal portion, and other regions In the region close to the boundary portion, the laser output and the fluid supply pressure are relatively lowered as compared with the other regions.

  In the present invention, in the electrophotographic photosensitive member in which the coating film removal portion is formed on at least one end portion of the cylindrical substrate having the coating film on the outer peripheral surface, the coating film side from the coating film removal boundary portion between the coating film and the coating film removal portion. In an image forming apparatus such as a copying machine or a laser printer, in particular, a small image forming apparatus, Even if the cleaning blade comes into contact with the coating film end of the photosensitive drum, the cleaning blade functions well, can maintain a good image quality, and can expand the effective image area of the photosensitive layer surface. .

  According to the present invention, there is provided a laser under fluid supply in an electrophotographic photoreceptor manufacturing method in which a coating film removing portion is formed on at least one end portion of a cylindrical substrate having a coating film coated on the outer peripheral surface by a dip coating method. In the coating film removal process by irradiation, the coating film removal target part is divided into at least two areas of the coating film and the coating film removal part near the coating film removal boundary part and other areas, and the area near the coating film removal boundary part Then, by relatively lowering the laser output and gas supply pressure compared to other areas, the edge coating film of the photosensitive drum formed by the dip coating method etc. can be efficiently and highly accurate. Can be removed.

  Embodiments of the present invention will be described below.

  As a result of intensive studies, the inventors of the present invention have defined the swell (projection) height of the coating film end portion of the photosensitive drum and the coating film residue thickness of the coating film removal portion within a specific range, thereby It has been found that even when the cleaning blade comes into contact with the end of the coating film, the function of the cleaning blade can be satisfactorily achieved and a good image quality can be maintained. Further, the present inventors have found a highly accurate method for removing a coating film by laser irradiation that can realize the rising height of the coating film end portion of the photosensitive drum and the coating film residue thickness of the coating film removing portion.

<Electrophotographic photoreceptor>
An outline of the appearance of the electrophotographic photosensitive member according to this embodiment is shown in FIG. The electrophotographic photoreceptor 10 has a coating film 14 such as a photosensitive layer on the outer peripheral surface of a cylindrical substrate 12, and a coating film removing unit 16 from which the coating film 14 is removed at one end of the cylindrical substrate 12 has an other end. The coating film unformed part 18 in which the coating film 14 is not formed is formed in each part. Here, the rising height of the coating film 14 within 2 mm from the coating film removal boundary between the coating film 14 and the coating film removing unit 16 to the coating film side is 10 μm or less, and the coating film residue of the coating film removing unit 16 The thickness is 0.1 μm or less.

  The rising height of the coating film 14 within 2 mm from the coating film removal boundary between the coating film 14 and the coating film removing unit 16 to the coating film side is 10 μm or less, but preferably 5 μm or less. If the raised height exceeds 10 μm, the cleaning blade that contacts the photosensitive drum rides on or rises up, and the cleaning blade is damaged or toner stains occur.

  Moreover, although the coating-film residue thickness of the coating-film removal part 16 is 0.1 micrometer or less, it is preferable that it is 0.05 micrometer or less. When the coating film residue thickness of the coating film removing unit 16 exceeds 0.1 μm, the coating film removing unit 16 is brought into contact with a roller for keeping the distance from the developing roll constant, or the developer provided in the developing device When a film for preventing leakage of the film comes into contact with the roller, the coating film is peeled off by the roller or the film and is mixed into a developing device and causes image quality defects.

  Here, the rising height of the coating film 14 within 2 mm from the coating film removal boundary between the coating film 14 and the coating film removing unit 16 and the coating film residue thickness of the coating film removing unit 16 are as follows: It can be measured using a surface roughness meter (Surfcom manufactured by Tokyo Seimitsu).

  As described above, in the electrophotographic photoreceptor 10 according to the present exemplary embodiment, the rising height of the coating film within 2 mm from the coating film removal boundary portion of the coating film 14 and the coating film removing unit 16 to the coating film side, and the coating film removal. By setting the thickness of the coating film residue of the section 16 within the above predetermined range, in an image forming apparatus such as a copying machine or a laser printer, particularly a small image forming apparatus, a cleaning blade is provided to the coating film end of the photosensitive drum. Even if they come into contact with each other, the function of the cleaning blade can be exhibited satisfactorily, a good image quality can be maintained, and the effective image area of the photosensitive layer surface can be expanded.

  Note that the electrophotographic photoreceptor 10 according to the present embodiment is manufactured by a dip coating method in which the cylindrical substrate 12 is dipped in a coating solution for coating formation, and the immersion position of the cylindrical substrate 12 is set, for example. By adjusting and exposing the upper end portion of the cylindrical substrate 12, the coating film non-formed portion 18 where the coating film 14 is not formed is formed on the upper end portion of the cylindrical substrate 12, and then the coating film 14 is formed on the lower end portion of the cylindrical substrate 12. The removed coating film removal part 16 is formed. In the present embodiment, coating film removal portions 16a and 16b from which the coating film 14 has been removed are respectively formed at both ends of the cylindrical substrate 12 on which the coating film 14 has been formed by a dip coating method or the like, as shown in FIG. It may be what was done. In that case, the rising height of the coating film 14 within 2 mm from the respective coating film removal boundary portions of the coating film 14 and the coating film removing portions 16a and 16b to the coating film side is 10 μm or less, respectively, and the coating film is removed. The coating film residue thicknesses of the portions 16a and 16b are each 0.1 μm or less.

  FIG. 3 shows an example of the layer structure of the electrophotographic photoreceptor 10 in the present embodiment. The coating film 14 has an undercoat layer 20, a charge generation layer 22 containing a charge generation material, and a photosensitive layer 26 containing a charge transport layer 24 containing a charge transport material. The order of stacking the charge generation layer 22 and the charge transport layer 24 may be reversed. These are laminated photoconductors in which a charge generation material and a charge transport material are contained in separate layers (charge generation layer, charge transport layer), but both the charge generation material and the charge transport material are the same. A single-layer type photoreceptor included in the above layer may be used, and a laminated photoreceptor is preferable. Further, an intermediate layer may be provided between the undercoat layer 20 and the photosensitive layer 26.

  As the cylindrical substrate 12, a cylindrical body having a diameter of 10 to 200 mm and a length of 250 to 1000 mm is usually used. The cylindrical substrate 12 is made of a conductive material such as a metal material such as aluminum, stainless steel or nickel, a polymer material such as polyethylene terephthalate, polybutylene terephthalate, polypropylene, nylon, polystyrene or phenol resin, or an insulating material such as hard paper. Examples include those obtained by conducting a conductive treatment by dispersing a substance, those obtained by laminating metal stays on the above insulating material, and those obtained by forming a metal vapor deposition film on the above insulating material, and aluminum is usually used.

  Further, the cylindrical substrate 12 may be subjected to a surface treatment such as an anodizing treatment, a rough grinding treatment, and a honing treatment. By such surface treatment, the surface roughness of the conductive substrate is set within a predetermined range (preferably the arithmetic average roughness Ra is 0.05 to 0.5 μm and the maximum height Rmax is 0.5 to 5 μm). , Light interference can be prevented.

  The undercoat layer 20 has a surface concealment of the cylindrical substrate 12 and improved adhesion to the photosensitive layer 26, a charge holding function of the photosensitive layer 26, and the like, and is formed by the materials and manufacturing methods described below. The undercoat layer 20 may be composed of a single polymer compound, but may be composed of a polymer compound in which fine particles are dispersed, a mixture of a polymer compound and an organometallic compound, or the like.

  Examples of the polymer compound include acetal resins such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, and chloride. Examples thereof include vinyl-vinyl acetate-maleic anhydride resin, silicon resin, silicone-alkyd resin, phenol resin, phenol-formaldehyde resin, melamine resin and the like.

  Examples of the fine particles dispersed in the polymer compound include metal oxides such as zinc oxide and titanium oxide, silicon compounds such as silicon resin and silicon dioxide, and fluorine compounds such as Teflon (registered trademark). The particle diameter of the fine particles is preferably in the range of 0.1 to 3 μm. The fine particles are usually contained in the undercoat layer 18 in an amount of 10 to 60% by mass, more preferably 30 to 70% by mass. When preparing the coating solution for forming the undercoat layer, fine particles are added to a solvent in which the polymer compound is dissolved, and a dispersion treatment is performed. As a method for dispersing the fine particles in the polymer compound, methods such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker can be used.

  Examples of the organometallic compound to be mixed with the polymer compound include organometallic compounds containing silicon, zirconium, titanium, aluminum, manganese atoms, and the like. These organometallic compounds can be used alone or as a mixture of a plurality of types of organometallic compounds. Among them, an organometallic compound containing a silicon atom or a zirconium atom is excellent in performance, such as a low residual potential, a small potential change due to the environment, and a small potential change due to repeated use.

  Although the organometallic compound containing a silicon atom is not particularly limited, among them, organometallic compounds that are particularly preferably used are vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane. 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) Silane coupling agents such as 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane is there

  Examples of organometallic compounds containing a zirconium atom include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, Zirconium octanoate, zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Examples of organometallic compounds containing titanium atoms include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate , Titanium lactate ammonium salt, titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, polyhydroxy titanium stearate and the like.

  Examples of the organometallic compound containing an aluminum atom include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) and the like.

  The thickness of the undercoat layer 20 is preferably in the range of 0.1 to 30 μm. When the undercoat layer 20 is composed of a polymer compound in which fine particles such as metal oxide are dispersed, the thickness is preferably in the range of 10 μm to 30 μm. When the molecular compound is composed of a simple substance or a mixture of a polymer compound and an organometallic compound, the thickness is preferably in the range of 0.1 to 10 μm.

  Examples of the charge generation material contained in the charge generation layer 22 of the photosensitive layer 26 include azo pigments such as bisazo and trisazo, condensed aromatic pigments such as dibromoanthanthrone, perylene pigments, pyrrolopyrrole pigments, and phthalocyanine pigments. All can be used, but metal and metal free phthalocyanine pigments are particularly preferred. Among them, hydroxygallium phthalocyanine disclosed in JP-A-5-263007 and JP-A-5-279591, chlorogallium phthalocyanine disclosed in JP-A-5-98181, JP-A-5-140472 and special Dichlorotin phthalocyanine disclosed in Kaihei 5-140473 and titanyl phthalocyanine disclosed in JP-A-4-189873 and JP-A-5-43813 are particularly preferred.

  The charge generation layer 22 is formed by applying the above charge generation material onto a substrate together with a binder resin using an appropriate solvent. The binder resin can be selected from a wide range of insulating resins. Preferred resins include polyvinyl butyral resin, polyarylate resin, polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin, poly Examples of the insulating resin include, but are not limited to, acrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, polyvinyl alcohol resin, and polyvinyl pyrrolidone resin. It can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane. These binder resins can be used alone or in admixture of two or more.

  The mixing ratio of the charge generation material and the binder resin (mass ratio) is preferably in the range of 10: 1 to 1:10. In addition, as a method for dispersing them, a usual method such as a ball mill dispersion method, an attritor dispersion method, a sand mill dispersion method, or the like can be used. It is said. When dispersing, it is effective that the particles have a particle size of 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less.

  Solvents used for these dispersions include methanol, ethanol, N-propanol, N-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, N-butyl acetate, dioxane, tetrahydrofuran, Ordinary organic solvents such as chlorobenzene and toluene can be used alone or in admixture of two or more. Further, the thickness of the charge generation layer 22 used in the present embodiment is generally 0.1 to 5 μm, preferably 0.2 to 2 μm.

  Next, the charge transport layer 24 will be described. The charge transport layer 24 is formed containing a charge transport material and a binder resin, or is formed containing a polymer charge transport material.

  Charge transport materials include quinone compounds such as p-benzoquinone, chloranil, bromanyl, anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, xanthone compounds, benzophenone compounds Compounds, electron transport compounds such as cyanovinyl compounds, ethylene compounds, triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazone compounds, etc. Examples thereof include hole transporting compounds. These charge transport materials can be used alone or in combination of two or more, but are not limited thereto.

  The binder resin used for the charge transport layer 24 is polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile. Copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinyl Polymer charge transport materials such as carbazole, polysilane, and polyester-based polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 can also be used. These binder resins can be used alone or in combination of two or more.

  The blending ratio (mass ratio) of the charge transport material and the binder resin is preferably in the range of 10: 1 to 1: 5. In addition, as a method for dispersing them, usual methods such as a ball mill dispersion method, an attritor dispersion method, and a sand mill dispersion method can be used.

  Solvents used for these dispersions include aromatic hydrocarbons such as toluene, xylene and chlorobenzene, ketones such as acetone and 2-butanone, and cyclic or linear ethers such as tetrahydrofuran and ethyl ether. Ordinary organic solvents can be used alone or in admixture of two or more. The thickness of the charge transport layer 24 is generally 5 to 50 μm, preferably 10 to 35 μm.

  In addition, examples of the method for applying the coating liquid include a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method. A dip coating method (dip coating method) is used.

<Method for producing electrophotographic photoreceptor>
In the method of manufacturing an electrophotographic photosensitive member according to this embodiment, a coating film on at least one end of a cylindrical substrate applied by a dip coating method or the like is irradiated with a CO ₂ laser or the like under supply of side gas and center gas. When the coating film removal part is formed on at least one end of the cylindrical substrate by peeling or melting by the above, the coating film removal target part is divided into at least two areas, and in the area closest to the coating film removal boundary part, The laser output and the center gas supply pressure are lowered relative to the region.

  An outline of an example of a coating film removing apparatus according to an embodiment of the present invention is shown in FIG. The coating film removing apparatus 1 includes a laser oscillator 30, a center gas nozzle 32, and a side gas nozzle 34.

  An operation of the electrophotographic photosensitive member manufacturing method and the coating film removing apparatus 1 according to this embodiment will be described.

  In the coating film removing apparatus 1 of FIG. 4, at least one end portion of the coating film 14 is mounted on a holder (not shown) on which an electrophotographic photosensitive member 10 to be coated is removed, and is rotated in the lateral direction (axial direction). Moveable movement. The laser light 36 is irradiated from a laser oscillator 30 through a lens and a mirror to at least a part of the coating film removal target portion 38 at the end of the electrophotographic photosensitive member 10 from the tip of the center gas nozzle 32 with a predetermined width. At that time, a side gas nozzle 34 for supplying a fluid for removing the melt of the coating film from the vicinity of the laser beam irradiation unit 40 is installed toward the laser beam irradiation unit 40, and the melt of the coating film is irradiated by the side gas to the laser beam irradiation unit. It is removed from around 40.

  During the removal of the coating film 14 by the coating film removing apparatus 1, the electrophotographic photosensitive member 10 is mounted on the holder and rotated about the axis l. The rotation speed is preferably about 200 rpm to about 4000 rpm, and is appropriately selected within the range. The electrophotographic photosensitive member 10 is moved in the axial direction, and the moving speed (processing speed) is preferably in the range of 10 to 800 mm / min, and is appropriately selected within the range.

  The laser light oscillated from the laser oscillator 30 is focused by an optical system and irradiated onto at least a part of the coating film removal target portion 38 of the electrophotographic photosensitive member 10. At this time, the laser beam 36 obtains the maximum energy density at the focal point 42 in FIG. However, at the focal point 42, the irradiation area is minimized and the removal width is narrowed. In order to efficiently remove the coating film, it is preferable to irradiate the surface of the electrophotographic photosensitive member 10 at a distance D3 from the focal point 42 in order to widen the irradiation area in a range where the energy density does not substantially decrease. Usually, the distance D3 is selected in the range of about 3 to 20 mm. Further, the laser light may be applied to the surface of the electrophotographic photosensitive member 10 at a distance −D3 from the focal point 42.

The laser used in the method according to this embodiment is preferably a continuous wave CO ₂ laser (carbon dioxide laser). As described in Japanese Patent Laid-Open No. 7-13348, CO ₂ laser light having an oscillation wavelength of 10.6 μm generally has a characteristic of being well absorbed by a polycarbonate resin used for a coating layer of an electrophotographic photosensitive member. Therefore, it can be said that this method is a suitable laser type. Further, since the CO ₂ laser is hardly absorbed by aluminum that is often used as a cylindrical substrate of an electrophotographic photosensitive member, the coating film can be removed without damaging the aluminum substrate. Other than the CO ₂ laser, for example, a YAG laser or the like can be used.

  The laser preferably has sufficient power to remove the coating, and the inventors have found that a suitable output is in the range of 400 W to 2000 W, more preferably in the range of 600 W to 1200 W. If the laser output is less than 400 W, the coating film may not be sufficiently removed, and if it exceeds 2000 W, damage to the aluminum substrate cannot be ignored, which is not preferable. As a device for performing such laser irradiation, a commercially available laser processing machine can be used, and for example, a mel laser ML3020D manufactured by Mitsubishi Electric can be used.

  In FIG. 4, since the coating film 14 in the portion irradiated with the laser is immediately melted, it is blown off by the fluid sprayed from the side gas nozzle 34 so as to be quickly removed from this place. The side gas is preferably injected at a pressure in the range of about 0.1 MPa to about 2 MPa. If the supply pressure of the side gas is less than 0.1 MPa, it may be difficult to quickly remove the melted coating film. If the supply pressure exceeds 2 MPa, the blown-off molten coating film will be widely scattered and clean. The coating film may not be removed.

  Further, the laser beam irradiation unit 40 is irradiated with fluid from the center gas nozzle 32 in the same direction as the laser beam. The center gas also serves to protect the optical system by preventing fragments and generated gas from flowing back into the laser optical system during laser irradiation. The center gas is preferably injected at a pressure in the range of about 0.001 MPa to about 2 MPa. If the supply pressure of the center gas is less than 0.001 MPa, the protective function of the optical system may not be fulfilled. If the supply pressure exceeds 2 MPa, the blown-off molten coating is widely scattered, and a clean coating is removed. May not be possible.

  In order to melt and remove the coating film 14 efficiently and stably over a long period of time, it is preferable to perform laser irradiation while simultaneously injecting the side gas and the center gas. Both fluids are preferably gases, and the gas species is preferably air. However, when the material of the coating film 14 is highly reactive or combustible, an inert gas such as nitrogen gas should be used. Is also possible.

  6 and 7 show the arrangement of the preferred laser beam 36, the center gas nozzle 32, and the side gas nozzle 34 from the cross-sectional direction and the lateral direction, respectively. As shown in FIG. 6, the laser beam 36 is applied to the surface of the electrophotographic photosensitive member 10 with an offset of a distance D2 from the center of the electrophotographic photosensitive member 10. D2 is selected in accordance with the diameter of the electrophotographic photoreceptor 10 within a range of about 5 mm to 15 mm. When D2 is 0 mm, that is, when the laser beam 36 is irradiated to the central portion of the electrophotographic photosensitive member 10, the laser beam 36 is regularly reflected in the direction of the light source portion of the center gas nozzle 32, which may cause deterioration of the center gas nozzle 32 and the optical system.

  The side gas nozzle 34 is installed at an angle α in FIG. 6 and an angle β in FIG. 7 with respect to the center gas nozzle 32, and ejects fluid toward the laser light irradiation unit 40. The angles α and β are each preferably in the range of 15 ° to 80 °, and more preferably set separately in the range of 30 ° to 60 °. In particular, the angle β is preferably set so as to face the terminal portion at one end of the electrophotographic photosensitive member 10. Further, the distance D1 between the opening of the side gas nozzle 34 and the electrophotographic photosensitive member 10 in FIG. 6 can be arbitrarily set according to the pressure of the side gas and the nozzle opening area, but is usually set in the range of 5 mm to 100 mm.

  As shown in FIG. 8, the width D4 of the coating film removing portion 16 at the end of the electrophotographic photosensitive member 10 is set as necessary up to about 1 mm to 20 mm, and the electrophotographic photosensitive member 10 is changed according to the width D4. The coating film 14 is removed by relatively moving in the axial direction while rotating. In this case, it may be removed from the direction of one end of the electrophotographic photosensitive member 10 toward the center of the electrophotographic photosensitive member 10, or vice versa. In any case, in this embodiment, as shown in FIG. 8, the coating film removal target portion 38 is divided into a plurality of areas (in FIG. 8, two areas A area and B area), and at the coating film removal boundary portion of that area. By setting the removal condition of the closest region (B region in FIG. 8) to be relatively lower than the other region (A region in FIG. 8), the laser output and the center gas pressure are relatively reduced, thereby removing the coating film removal boundary portion. The height of burr rise can be dramatically reduced. Moreover, when making the width | variety of the area | region (B area | region in FIG. 8) nearest to a coating-film removal boundary part small, for example to set it as 1.0-1.4 mm, a side gas pressure is relative compared with another area | region. It is preferable to set so as to increase.

  In the normal coating film removal target part (A area in FIG. 8), the laser output capable of melting the coating film 14 and the removal of the coating film fragments after melting are appropriately performed by blowing off the side gas and the center gas as appropriate. To be implemented. When removal is performed up to the coating film removal boundary (B area in FIG. 8) under the same conditions, the molten coating rides near the coating film removal boundary mainly by the action of the center gas at the last coating film removal boundary. It will solidify when output stops. This forms a burr-like bulge in the vicinity of the coating film removal boundary. By reducing the laser output relatively in a region close to the coating film removal boundary as in this embodiment, the amount of coating film melted can be reduced. At the same time, by reducing the pressure of the center gas, the effect of the side gas is relatively enhanced, and the movement of the molten coating film toward the coating film removal boundary portion can be reduced. As a result, burr-like bulge in the vicinity of the coating film removal boundary can be reduced.

  In the region close to the coating film removal boundary, the laser output and the center gas pressure are relatively lowered as compared with other regions, but the laser output is 1 of the laser output of the normal coating film removal target portion (A region in FIG. 8). It is preferable to reduce to about / 4 to 1/2. When the laser output is less than ¼ of the normal coating film removal target portion in the region close to the coating film removal boundary, the coating film may not be sufficiently removed. The swell reduction effect may be reduced. Further, along with this, it is preferable to lower the moving speed (processing speed) of the electrophotographic photosensitive member 10 in the axial direction from other regions, and is about 1/4 to 1/2 of the moving speed of the normal coating film removal target portion. It is preferable to lower it. If the moving speed is less than ¼ of the normal coating removal target area in the area close to the coating film removal boundary, the productivity may be reduced. There is a case. The center gas supply pressure is preferably in the range of 0.001 MPa to 0.01 MPa. When the supply pressure of the center gas is less than 0.001 MPa in the region close to the coating film removal boundary, the role of protecting the optical system may not be fulfilled. There is.

  In the entire width of the coating film removal target portion 38, the width of the region closest to the coating film removal boundary portion (B region in FIG. 8) is preferably 1.0 mm to 3.0 mm, and 1.2 mm to 2.0 mm. It is more preferable that When the width is less than 1.0 mm, the coating film fragments melted in the other region (A region in FIG. 8) remain up to the vicinity of the coating film removal boundary portion, resulting in swell and less swell reduction effect. Thus, if the length is longer than necessary such that it exceeds 3.0 mm, the overall removal rate is slowed down, so that the productivity may be lowered.

  In the above-described method, the coating film removal target portion 38 is divided into two areas, the A area and the B area, and the laser output and the center gas supply pressure are relative to each other in an area close to the coating film removal boundary stepwise. Although the method of removing the coating film by reducing it to the above has been described, the coating film removal target portion 38 is divided into three or more regions, and the laser output and the center gas supply pressure in a region close to the coating film removal boundary step by step. The coating film may be removed by lowering the relative thickness. Practically, it is sufficient to divide into two areas. In the coating film removal target portion 38, the coating film may be removed by continuously reducing the laser output and the center gas supply pressure toward the coating film removal boundary.

  By peeling off the end of the electrophotographic photosensitive member 10 by the method of manufacturing the electrophotographic photosensitive member according to this embodiment, the desired coating film 14 can be removed cleanly, and the rising height of the coating film removal boundary portion is 10 μm or less, preferably 5 μm. The coating film residue thickness of the coating film removing unit 16 can be controlled to 0.1 μm or less, preferably 0.05 μm or less. That is, this embodiment does not require end wiping using a normal solvent, simplifies the manufacture of the electrophotographic photosensitive member 10, promotes automation, and can produce high productivity. In addition, the electrophotographic photoreceptor 10 manufactured in this way can maintain a good image quality without damaging the cleaning blade due to bulging in the copying apparatus. Furthermore, since the area | region of a coating-film removal part can be narrowed with width 1-2mm, for example, the effective image area | region of a photosensitive layer surface can be expanded.

  According to the method for producing an electrophotographic photoreceptor according to the present embodiment, a dip coating method may be used as a method for producing the electrophotographic photoreceptor 10 by forming a coating film 14 such as a photosensitive layer on the cylindrical substrate 12. The coating film at the lower end of the cylindrical substrate 12 can be removed with almost no burr bulging near the coating film removal boundary.

  In the method for producing an electrophotographic photosensitive member according to this embodiment, an electrophotographic photosensitive member in which an undercoat layer 20 is provided in addition to the photosensitive layer 26 as the coating film 14, and an electron in which two or more undercoat layers 20 are provided. The present invention can be applied to removal of end portions of any electrophotographic photosensitive member such as a photographic photosensitive member and an electrophotographic photosensitive member in which a protective layer is further provided on the photosensitive layer 26.

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

Example 1
100 parts by mass of zinc oxide (average particle size 70 nm, Teica product, specific surface area value 15 m ² / g) is stirred and mixed with 500 parts by mass of toluene, and a silane coupling agent (KBM603, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.25 Mass parts were added and stirred for 2 hours. Thereafter, toluene was distilled off under reduced pressure, and baking was performed at 150 ° C. for 2 hours to obtain a surface-treated zinc oxide pigment.

  60 parts by mass of zinc oxide subjected to the surface treatment, 13.5 parts by mass of hardener-blocked isocyanate (Sumijoule 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.) and 15 parts by mass of butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) 38 parts by mass of a solution dissolved in 85 parts by mass of methyl ethyl ketone and 25 parts by mass of methyl ethyl ketone were mixed, and dispersion was performed for 2 hours with a sand mill using 1 mmφ glass beads. As a catalyst, 0.005 part by mass of dioctyltin dilaurate and 3.4 parts by mass of silicon resin particles (Tospearl 130, manufactured by GE Toshiba Silicone) were added to the resulting dispersion to obtain an undercoat layer coating solution. This coating solution was applied on an aluminum substrate having a diameter of 30 mm, a length of 327.5 mm, and a thickness of 1 mm by a dip coating method, followed by drying and curing at 170 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 25 μm.

  Next, in the X-ray diffraction spectrum using Cukα rays as the charge generation material, at Bragg angles (2θ ± 0.2 °) of 7.4 °, 16.6 °, 25.5 ° and 28.3 ° 1 part by mass of chlorogallium phthalocyanine having a strong diffraction peak is mixed with 1 part by mass of polyvinyl butyral (trade name: S-REC BM-S manufactured by Sekisui Chemical Co., Ltd.) and 100 parts by mass of n-butyl acetate, and the mixture is mixed with glass beads. Dispersion treatment was performed for 1 hour with a paint shaker to obtain a dispersion for forming a charge generation layer. This dispersion was applied onto the undercoat layer by a dip coating method, and this was heated and dried at 100 ° C. for 10 minutes to obtain a charge generation layer having a thickness of about 0.15 μm.

  Subsequently, a charge transport layer was formed on the charge generation layer by the following procedure. Charge resin 1 having a pendidine structure (N, N′-Diphenyl-N, N′-Bis (3-Methylphenyl) -based on 50 parts by mass of bisphenol Z polycarbonate resin (Iupilon Z300, manufactured by Mitsubishi Gas Chemical) as a binder resin 1,1′-Biphenyl-4,4′-Diamine) 15 parts by mass, triarylamine structure charge transfer agent 2 (N, N-Bis (3,4-dimethylphenyl) biphenyl-4-amine) 30 parts by mass, 1 part by weight of antioxidant 1 (2,6-Di-tert-butyl-p-cresol: BHT) and antioxidant 2 (2,2′-methylene-bis- (4-methyl-6-tert-butylphenol: MDPS) 4 parts by mass, tetrahydroph (THP) and monochlorobenzene (MCB) mixed solvent (mass mixing ratio 75:25) was added to make the total amount, and a toluene solution of dimethylpolysiloxane (KP340, manufactured by Shin-Etsu Chemical Co., Ltd.) as a leveling agent was added to monochlorobenzene. An amount equivalent to 4.5 ppm of a material diluted to 1/100 by mass ratio was added and mixed and stirred with a stirrer for 12 hours.When the composition is clearly shown, charge transport agent 1:15 parts by mass, charge transport agent 2:30 parts by mass Antioxidant: 5 parts by mass, Binder resin: 50 parts by mass, Leveling agent: 4.5 ppm This coating solution is a membrane filter (fluoropore, FP-1000, Sumitomo Electric Industries) made of Teflon (registered trademark) with a pore size of 10 μm. The mixed foreign matter was removed by applying pressure to the charge generation layer using a dip coating method, and 135 ° C. A 25 μm charge transport layer was formed by heating and drying at 60 ° C. All the dip coating described above was performed by adjusting the immersing position of the cylindrical aluminum substrate to expose the upper end of the cylindrical substrate. A coating film non-formed part where a coating film was not formed was formed on the upper end part of 10 mm.

The thus-prepared electrophotographic photosensitive drum 10 mm is irradiated with a laser under the following conditions to remove the coating film (width D4 = 10 mm). Formed. Table 1 shows the main conditions.
Laser oscillator: ML3122VZ1-3020D CO ₂ gas laser manufactured by Mitsubishi Electric Photosensitive drum rotation speed: 1200 rpm
Center gas nozzle hole diameter: 1.8mm
Center gas nozzle-drum distance: 12mm
Center nozzle offset amount D2: 10 mm
Laser focus position D3: 9 mm
Side gas nozzle hole diameter: 2mm
Side gas nozzle-drum distance D1: 15 mm
Side gas nozzle angle α: 30 degrees, angle β: 30 degrees <A region: 8.5 mm from drum end>
Laser output: 800W
Processing speed: 360 mm / min
Center gas pressure: 0.9 MPa
Side gas pressure: 0.7 MPa
<B area: 1.5 mm after A area>
Laser power: 400W
Processing speed: 180mm / min
Center gas pressure: 0.002 MPa
Side gas pressure: 0.7 MPa

(Example 2)
A sample of Example 2 was produced in the same manner as Example 1 except for the conditions shown in Table 1.

(Example 3)
The conditions shown in Table 1 are the same as in Example 1, but laser irradiation is started from the coating film removal boundary (B region) and removed toward the end of the drum (A region), that is, laser irradiation with Example 1. A sample of Example 3 was produced with the direction reversed. (Other conditions are the same as in Example 1.)

(Comparative Examples 1 and 2)
Samples of Comparative Examples 1 and 2 were produced in the same manner as in Example 1 except for the conditions shown in Table 1.

(Comparative Example 3)
For the electrophotographic photosensitive drum produced in Example 1, tetrahydrofuran was used as a solvent, and the drum lower end was immersed in tetrahydrofuran and rotated, and a plate blade made of high-density polyethylene was brought into contact with the drum. The film was scraped off to form a coating film removal portion having a width D4 = 10 mm, and a sample of Comparative Example 3 was produced.

  The coating film state in the vicinity of the coating film removal boundary portion of the photoconductor drum thus produced was measured using a surface roughness meter (Surfcom manufactured by Tokyo Seimitsu). Moreover, the coating-film residue of the whole coating-film removal part area | region (A area | region + B area | region) was measured with the surface roughness meter similarly to the above. Each sample was measured at four locations in the circumferential direction, and the average value was calculated. The results are shown in Table 2. 9A to 9C show profiles in the vicinity of the coating film removal boundary portion of the photosensitive drums produced in Example 1, Comparative Example 1, and Comparative Example 3, respectively. FIG. 9A shows a profile in the vicinity of the coating film removal boundary portion of the photosensitive drum manufactured in Example 1, and FIG. 9B shows a profile in the vicinity of the coating film removal boundary portion of the photosensitive drum manufactured in Comparative Example 1. FIG. 9C shows a profile in the vicinity of the coating film removal boundary portion of the photosensitive drum produced in Comparative Example 3.

  As described above, the photosensitive drums manufactured in Examples 1 to 3 were all stably produced with the height of the raised portion near the coating film removal boundary portion being 10 mm or less. In addition, the coating film removal part in general had no coating film residue and could be peeled off very cleanly. On the other hand, the photosensitive drum manufactured in Comparative Example 1 can be rapidly bulged in the vicinity of the coating film removal boundary, and the photosensitive drum manufactured in Comparative Example 2 has a relatively small rising portion, but the coating film is relatively thin. It was in the state in which the peeling residue of the coating film remained on one side in the removal part. Further, the photosensitive drum manufactured in Comparative Example 3 was in a state of being swelled although it was not compared with Comparative Example 1 in the vicinity of the coating film removal boundary.

  Next, these photoconductor drums were mounted on a modified DocuPrint C2425 machine manufactured by Fuji Xerox, and 2000 print tests were performed. As a result, the photosensitive drums of Examples 1 to 3 were able to maintain good image quality to the end, and the cleaning blade was not damaged. In the photoconductive drums of Comparative Examples 1 and 3, unevenness in image quality due to toner contamination appeared at the lower end of the photoconductor, and the cleaning blade in contact with the lower end was damaged. Further, the photosensitive drum of Comparative Example 2 had a problem such that the coating film remaining at the lower end was peeled off and mixed in the developing device.

  Thus, by peeling off the end portions of the photosensitive drums of Examples 1 to 3, the desired coating layer could be removed cleanly, and the rising height of the coating layer removal boundary portion could be controlled to 10 μm or less. In other words, the present invention does not require end wiping using a normal solvent, simplifies the production of the photosensitive drum, promotes automation, and produces high productivity. In addition, the photoconductor drum produced in this way was able to maintain good image quality without damaging the cleaning blade due to bulging in the copying apparatus.

1 is a diagram illustrating an outline of an example of a configuration of an electrophotographic photoreceptor according to an embodiment of the present invention. It is a figure which shows the outline of the other example of a structure of the electrophotographic photoreceptor which concerns on embodiment of this invention. FIG. 2 is a diagram schematically illustrating an example of a layer configuration of an electrophotographic photosensitive member according to an embodiment of the present invention. It is a figure which shows the outline of a structure of the coating-film removal apparatus which concerns on embodiment of this invention. It is a figure explaining the positional relationship of the laser irradiation in the manufacturing method of the electrophotographic photoreceptor which concerns on embodiment of this invention. It is a schematic sectional drawing which shows the photoreceptor end part coating film removal method in the manufacturing method of the electrophotographic photoreceptor which concerns on embodiment of this invention. It is a schematic side view which shows the photoreceptor end part coating-film removal method in the manufacturing method of the electrophotographic photoreceptor which concerns on embodiment of this invention. It is a figure explaining division | segmentation of the coating-film removal object part in the manufacturing method of the electrophotographic photoreceptor which concerns on embodiment of this invention. (A) It is a figure which shows the profile of the coating-film removal boundary part vicinity of the photosensitive drum produced in Example 1 of this invention. (B) It is a figure which shows the profile of the coating-film removal boundary part vicinity of the photosensitive drum produced in the comparative example 1 of this invention. (C) It is a figure which shows the profile of the coating-film removal boundary part vicinity of the photoreceptor drum produced in the comparative example 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coating film removal apparatus, 10 Electrophotographic photosensitive member, 12 Cylindrical base | substrate, 14 Coating film, 16, 16a, 16b Coating film removal part, 18 Coating film non-forming part, 20 Undercoat layer, 22 Charge generation layer, 24 Charge Transport layer, 26 photosensitive layer, 30 laser oscillator, 32 center gas nozzle, 34 side gas nozzle, 36 laser light, 38 coating film removal target part, 40 laser light irradiation part, 42 focus.

Claims (2)

An electrophotographic photosensitive member having a coating film removal portion formed on at least one end of a cylindrical substrate having a coating film on an outer peripheral surface,
The rising height of the coating film within 2 mm from the coating film removal boundary part of the coating film and the coating film removal part to the coating film side is 10 μm or less, and the coating film residue thickness of the coating film removal part is 0 An electrophotographic photoreceptor having a thickness of 1 μm or less. A method for producing an electrophotographic photosensitive member, wherein a coating film removing portion is formed on at least one end portion of a cylindrical substrate having a coating film applied to the outer peripheral surface by a dip coating method,
By irradiating a laser while supplying a fluid to at least a part of the coating film removal target portion to be removed, the end coating film on the cylindrical substrate on which the coating film is formed is removed and applied. Having a coating removal process to form a film removal section,
In the coating film removal step, the coating film removal target portion is divided into at least two regions, a region near the coating film removal boundary portion of the coating film and the coating film removal portion, and a region other than that, and a region near the boundary portion Then, the method for producing an electrophotographic photosensitive member, wherein the laser output and the fluid supply pressure are relatively lowered as compared with the other regions.

Images