JP2007219085A - Method for manufacturing electrophotographic conductive member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To propose a method for manufacturing an electrophotographic conductive member which prevents toner or additive from adhering even in the case of a manufacturing method adopting radiation of an energy ray, prevents a body to be electrified from being soiled even when film thickness is very thin, and is free from harmful effect occurring when forming a film such as unevenness in the film thickness, high resistance or increase of cost. <P>SOLUTION: In the method for manufacturing the electrophotographic conductive member, a coating liquid whose transmittance is 100% to ≥20% is applied to the surface of a conductive elastic body, and ultraviolet rays are radiated thereafter, so that the surface of the conductive elastic body is crosslinked through the coating liquid. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing an electrophotographic conductive member such as a developing member, a charging member, or a transfer member used in an electrophotographic apparatus.

  Conventionally, many methods are known as electrophotographic methods. As a general example, an electric latent image is formed by applying a potential to a charged object using a photosensitive (photoconductive) substance (charging process) and partially exposing the charged object. (Exposure process), and then the latent image is made visible with toner (development process), and the toner image is transferred to a transfer material such as paper (transfer process). Thereafter, the toner is transferred onto the transfer material by heat, pressure, etc. There is a method of fixing an image (fixing step) to obtain an image. In addition, an additional process such as removing toner particles remaining on the charged body without being transferred onto the transfer material from the charged body by various means (cleaning process) may be added.

  In such an electrophotographic method, a conductive elastic body is used as a charging member, a developing member, and a transfer member. When a conductive elastic body is used, the charged body is not damaged even when used in contact with a charged body such as an organic photoreceptor (OPC). However, when rubber or thermoplastic elastomer is used as an elastic body, the following problems occur. 1) Since the friction is large and the adhesiveness is high, the toner and the external additive adhere to the conductive elastic body, resulting in an image defect. 2) The low molecular weight component in the elastic body is formed on the surface of the electrophotographic conductive member. Bleed out (bleeded or bloomed), and image defects caused by adhering to the surface of the charged body occur (referred to as contamination of the charged body).

  Conventionally, as a method for producing a conductive elastic body to improve this problem, a method of irradiating the surface of the conductive elastic body with energy rays (ultraviolet rays, electron beams, corona discharge, etc.) (see, for example, Patent Document 1), conductivity. A method of providing a surface layer made of a material different from the elastic body by coating, tube coating, or the like (see, for example, Patent Document 2) has been proposed.

In particular, in the manufacturing method for forming the surface layer, as a method for preventing the adhesion of the toner and the external additive and preventing the contamination of the charged body, an ultraviolet curable resin is applied and the coated surface is applied. There is a manufacturing method in which ultraviolet rays are irradiated and cured. (For example, refer to Patent Document 3.)
JP-A-9-160355 JP-A-8-160354 JP 2002-310136 A

  In the conventional production method of irradiating energy rays, the surface of the conductive elastic body is cross-linked by the energy rays, and the dynamic friction coefficient is reduced, but at the same time, oxidation occurs, so the contact angle of the electrophotographic conductive member surface decreases. It was. Due to the decrease in the contact angle, the toner and the external additive are likely to adhere, causing image defects. In addition, the prevention of charged object contamination was insufficient.

  On the other hand, in the manufacturing method that forms a surface layer of a material different from the conventional conductive elastic body, regardless of whether it is a thermosetting resin or an ultraviolet curable resin, the coefficient of dynamic friction is reduced or the migration of contaminants to be charged is prevented. In order to do so, it was necessary to increase the thickness of the coating film (several μm or more). At this time, as the film thickness is increased, adverse effects such as 1) non-uniform film thickness such as sag and cracks, 2) higher resistance, and 3) higher cost also occur. In the manufacturing method of applying the ultraviolet curable resin of JP-A-2002-310136 and irradiating the applied surface with ultraviolet rays to cure, the thickness of the coating film is optimally 5-30 μm, The above issues may occur.

  The object of the invention according to the present application is to prevent the toner and external additives from adhering even in the production method of irradiating energy rays, and to prevent the object to be charged from being contaminated even with a very thin film thickness. The present invention proposes a method for producing a conductive member for electrophotography that is free from adverse effects that occur during film formation such as non-uniformity, high resistance, and high cost.

  The first invention according to the present application for solving the above-mentioned problems is the step of forming a coating film having an ultraviolet transmittance of 100% or less and 20% or more on the surface of the conductive elastic body, and irradiating the coated surface with ultraviolet rays. A method for producing a conductive member for electrophotography, characterized in that the surface of the conductive elastic body is cross-linked by ultraviolet rays that have passed through the coating film when irradiated with ultraviolet rays.

  According to the first invention, it is possible to manufacture an electrophotographic conductive member having a small dynamic friction coefficient, a high contact angle, no oozing from an elastic body, and no adverse effects during film formation due to a thick coating film.

  In a second invention according to the present application for solving the above-mentioned problems, the coating film is formed using a paint having at least one functional group selected from a double bond, an epoxy group, an acrylate group, and an isocyanate group. It is a manufacturing method of the electrophotographic electroconductive member of Claim 1 characterized by the above-mentioned.

  According to the second invention, since the coating film and the elastic body surface can be simultaneously crosslinked by ultraviolet rays, the production process is shortened compared to the case where the elastic body surface and the coating film are separately crosslinked, and bleeding from the elastic body is caused. A conductive member for electrophotography in which the removal is further suppressed by crosslinking of the coating film can be produced.

  According to a third aspect of the present invention for solving the above problems, an organic material containing an epoxy group and a cationically polymerizable catalyst is used in the coating film, using a conductive elastic material containing an epoxy group in the conductive elastic material. The method for producing an electrophotographic conductive member according to claim 1, wherein an inorganic hybrid sol is used.

  According to the third invention, the coating film and the elastic body surface can be simultaneously cross-linked by ultraviolet rays, and a strong coating film can be formed, so that the coating film is not scraped off even by rubbing against the charged body. There is no.

  As described above, by using the manufacturing method of the first invention according to the present application, there is no image defect due to adhesion of toner and external additives onto the conductive elastic body, and image defect due to contamination of the charged body. Therefore, it is possible to manufacture a conductive member for electrophotography that is free from harmful effects during film formation.

  By using the production method of the second invention, it becomes possible to shorten the production process by simultaneously crosslinking the elastic body surface and the coating film, and further to provide an electrophotographic conductive member free from image defects due to contamination of the charged body. Can be manufactured.

  By using the third production method, it is possible to produce an electrophotographic conductive member that does not cause image defects even when printing in large quantities.

  If the structure and form of the electrophotographic conductive member produced by the method for producing an electrophotographic conductive member of the present invention are shown as an example, as shown in FIG. The shaft is formed on the outer periphery of the shaft 11 and the surface of the conductive elastic body is cross-linked as compared with the inside of the conductive elastic body (conductive elastic body modification portion 13). An electrophotographic conductive member having a coating film 14 that is 20% or more can be exemplified.

  The conductive elastic body can be formed of rubber, a thermoplastic elastomer, or the like conventionally used as a conductive elastic body of a conductive member for electrophotography. As the rubber, a rubber composition containing polyurethane rubber, silicone rubber, butadiene rubber, isoprene rubber, chloroprene rubber, styrene-butadiene rubber, ethylene-propylene rubber, polynorbornene rubber, styrene-butadiene-styrene rubber, epichlorohydrin rubber or the like is suitable. Used for. The type of the thermoplastic elastomer is not particularly limited, and a thermoplastic elastomer composition containing one or more types of thermoplastic elastomers selected from general-purpose styrene elastomers and olefin elastomers is preferably used. it can.

  The rubber composition and the elastomer composition of the thermoplastic elastomer composition are within a range not losing the characteristics of the low dynamic friction coefficient, high contact angle, and low charged object contamination of the electrophotographic conductive member of the present invention. , Commonly used as compounding agents for rubber and thermoplastic elastomers, processing aids, crosslinking agents, crosslinking accelerators, crosslinking accelerators, crosslinking retarders, fillers, dispersants, foaming agents, lubricants, anti-aging agents Further, an ozone deterioration inhibitor, an antioxidant, a conductive agent, and the like can be added as appropriate.

  These rubbers and thermoplastic elastomers can be mixed with compounding agents by using a closed mixer such as a Banbury mixer, intermix or pressure kneader, or using an open mixer such as an open roll. Etc. can be illustrated.

  There is no restriction | limiting in particular as a shaping | molding method of the elastic body composition made in this way. As an example of a method for molding an elastic roller in which an elastic body is provided on a conductive support, two cylindrical pieces that concentrically hold a shaft-shaped conductive support are assembled in a cylindrical mold, and an elastic composition Injection molding that is molded by injecting an elastic material, after the elastic body composition is extruded into a tube shape, the conductive support body is covered with the tubular elastic body composition, or the conductive support body and the elastic body composition are integrated. There are extrusion molding, extrusion molding, press molding, and the like, which are extruded to form a cylindrical elastic body roller, but are not particularly limited. In view of shortening the manufacturing time, extrusion molding in which an elastic body composition is formed by extruding the elastic body composition integrally with the conductive support is preferable.

  When the elastic composition is a rubber composition, examples of the crosslinking method include mold vulcanization, can vulcanization, continuous vulcanization, far / near infrared rays, induction heating, and the like.

  Moreover, in order to make a desired roller shape and a roller surface roughness after the said shaping | molding, the dry grinding | polishing using a rotating grindstone may be performed.

  Methods for forming a coating film having an ultraviolet transmittance of 100% or less and 20% or more on the surface of the conductive elastic body include dipping coating, spray coating, ring coating (Japanese Patent Laid-Open No. 2005-321749), brush Although methods, such as coating, are mentioned, it is not limited to this. The ultraviolet transmittance indicates the transmittance at the peak wavelength of an ultraviolet lamp used in a subsequent process. In order to ensure the transmittance, the coating solution preferably has a high ultraviolet transmittance of the binder and no filler. Therefore, it is preferable that fine particles such as carbon black, metal and metal oxide used for conductivity control are not added to the coating film of the electrophotographic conductive member. Further, the lower the viscosity of the coating solution, the thinner the coating film and the higher the transmittance. Therefore, it is preferable to reduce the viscosity of the coating liquid by appropriately diluting with a solvent. At this time, the viscosity of the coating solution is more preferably 1 mPa · s or less as measured by a B-type viscometer. Further, the film thickness after the solvent is volatilized by adjusting the coating amount is preferably 1 μm or less. By doing so, although it depends on the material of the coating film, the transmittance of ultraviolet rays can be 20% or more. As the binder system of the coating liquid, a coating liquid such as silicone, fluorine, urethane, acrylic, urethane-modified acrylic, and silicone-modified urethane is used.

  A high-power low-pressure mercury lamp, an electrodeless low-pressure mercury lamp, an excimer lamp, a high-pressure mercury lamp, a metal halide lamp, or the like is used for ultraviolet irradiation after coating. Among these, the material of the high-output low-pressure mercury lamp and electrodeless low-pressure mercury lamp that is most suitable for the present invention is, for example, quartz glass, which has a titanium oxide film or a silica film formed on the inner and outer surfaces of the quartz glass. Some contain titanium or silica. With this material, wavelengths below 200 nm are cut. Further, it is preferable to use these lamps because the intensity of ultraviolet rays typified by a wavelength of 254 nm is 60% or more of the total wavelength intensity. The excimer lamp has a peak at a short wavelength of 172 nm and has few other peaks. When an excimer lamp is used, ultraviolet light having a wavelength of 172 nm absorbs oxygen and generates ozone, so that the surface of the electrophotographic conductive member is subjected to ozone treatment and is extremely oxidized. As a result, the contact angle of the roller surface with water tends to decrease, such being undesirable. Further, the high-pressure mercury lamp and the metal halide lamp are ultraviolet rays having a relatively long wavelength represented by a wavelength of 365 nm. When a high-pressure mercury lamp or a metal halide lamp is used, the influence of heat on the roller may increase and the rubber may deteriorate. Moreover, since the ultraviolet rays have a relatively long wavelength and the efficiency of the ultraviolet rays is poor, the irradiation time becomes long, which is not preferable. In addition, the degree of surface modification by ultraviolet rays can be adjusted by the integrated light quantity. The cumulative amount of ultraviolet light is defined below.

UV integrated light quantity (mJ / cm2) = UV intensity (mW / cm2) x irradiation time (sec)
What is necessary is just to select suitably the integrated light quantity of an ultraviolet-ray according to the effect of surface modification. The adjustment can be performed by any of irradiation time, lamp output, and distance between the lamp and the roller, and may be determined so as to obtain a desired integrated light amount.

  When irradiated with ultraviolet rays, the surface of the conductive elastic body and the coating film are oxidized by the ultraviolet rays themselves and ozone generated by the reaction between the ultraviolet rays and atmospheric oxygen. Therefore, it is preferable to add a silicone-based or fluorine-based material to the coating solution to suppress oxidation and suppress a decrease in contact angle.

  In addition, when the coating film has at least one functional group selected from a double bond, an epoxy group, an acrylate group, and an isocyanate group, the functional group reacts and crosslinks by irradiation with ultraviolet rays, so that the binder is tertiary. It is good because it forms a former network. The acrylate group may have a functional group other than hydrogen bonded to the α-position, such as methacrylate having a methyl group bonded to the α-position. It is preferable to add a catalyst that promotes the reaction of the functional group to these coating films because the cross-linking becomes denser and the production time can be shortened.

  In addition, in order to enhance the adhesion between the conductive elastic body and the coating film, an organic-inorganic hybrid sol containing an epoxy group-containing conductive elastic body, an epoxy group bonded to polysiloxane, and a cationically polymerizable catalyst is used as a coating liquid. More preferably, it is used. In this combination of materials, the polysiloxane easily transmits ultraviolet rays, and the cationically polymerizable catalyst is activated by the ultraviolet rays to open the epoxy groups contained in both the coating film and the conductive elastic body. To cross-link.

  The organic-inorganic hybrid sol is a sol state of an organic-inorganic hybrid material prepared by a so-called sol-gel method, and a mixture of hydrolyzable silane compounds including at least an hydrolyzable silane compound having an epoxy group is condensed by hydrolysis. And you can get it. A cationically polymerizable catalyst is added to the organic-inorganic hybrid sol, and the epoxy group is cleaved by irradiation with ultraviolet rays to be crosslinked to form an organic-inorganic hybrid gel. When this organic-inorganic hybrid gel is used as a coating film, it is more preferable because it is strong and has low friction and high contact angle.

  FIG. 2 shows an example in which the electrophotographic conductive member of the present invention is applied to an electrophotographic apparatus. Reference numeral 21 denotes a rotating drum type electrophotographic photosensitive member (charged member) as an image carrier. The charged body 21 is rotationally driven at a predetermined peripheral speed (process speed) in a clockwise direction indicated by an arrow in the drawing. As the object to be charged 21, for example, a known object to be charged having at least a roll-like conductive support and a photosensitive layer containing an inorganic photosensitive material or an organic photosensitive material on the support may be adopted.

  Reference numeral 22 denotes a charging roller to which the electrophotographic conductive member of the present invention is applied. As the charging device, known means other than the charging roller can be used. A charging unit is configured by the charging roller 22 and a charging bias application power source S1 that applies a charging bias to the charging roller 22. The charging roller 22 is brought into contact with the member to be charged 21 with a predetermined pressing force, and is driven to rotate in the forward direction with respect to the rotation of the member to be charged 21 in this example. A predetermined DC voltage (in this example, −1200 V) is applied to the charging roller 22 from the charging bias application power source S1, so that the surface of the charged body 21 has a predetermined polarity potential (in this example, a dark portion). Is uniformly charged (DC charging). In addition to this DC charging, known charging methods such as AC / DC superimposed charging and injection charging can be used.

  Reference numeral 23 denotes exposure means. A known means can be used as the exposure means 23. For example, a laser beam scanner or the like can be preferably exemplified.

  When the exposure unit 23 performs image exposure corresponding to the target image information on the charged surface of the object 21 to be charged, the potential of the exposed bright portion of the charged surface (in this example, the bright portion potential is −350 V). The electrostatic latent image is formed on the charged object 21 by being selectively lowered (attenuated).

  Reference numeral 24 denotes reversal developing means. As the developing unit 24, a known unit can be used. For example, the developing unit 24 in this example is provided in a toner container 24 a that is disposed in an opening of a developing container that stores toner and carries and transports toner. The agitating member 24b for agitating the toner that has been used, and the toner regulating member 24c for regulating the toner carrying amount (toner layer thickness) of the toner carrying member 24a. The developing means 24 is a toner (negative toner, in this example, charged with a developing bias of −350 V) charged to the exposed bright portion of the electrostatic latent image on the surface of the charged body 21 with the same polarity as the charged polarity of the charged body 21. ) Is selectively attached to visualize the electrostatic latent image as a toner image. There is no particular limitation on the development method, and all existing methods can be used. As existing methods, for example, there are a jumping development method, a contact development method, a magnetic brush method, and the like. Especially in an image forming apparatus that outputs a color image, a contact development method is used for the purpose of improving toner scattering properties. The developing roller is preferable. The electrophotographic conductive member of the present invention can be suitably used for this developing roller.

  Reference numeral 25 denotes a transfer roller using the electrophotographic conductive member of the present invention as a transfer means. The transfer roller 25 is brought into contact with the member to be charged 21 with a predetermined pressing force to form a transfer nip portion. The peripheral speed of the transfer roller 25 is approximately the same as the rotation peripheral speed of the member to be charged 21 in the forward direction with the rotation of the member to be charged 21. Rotate with. Further, a transfer voltage having a polarity opposite to the charging characteristics of the toner is applied from the transfer bias application power source S2. The transfer material P is fed to the transfer nip from a paper feed mechanism (not shown) at a predetermined timing, and the back surface of the transfer material P is opposite to the charging polarity of the toner by the transfer roller 25 to which a transfer voltage is applied. By being charged to the polarity, the toner image on the surface of the member to be charged 21 is electrostatically transferred to the surface side of the transfer material P at the transfer nip portion. The electrophotographic conductive member of the present invention can be suitably used for this transfer roller.

  The transfer material P that has received the transfer of the toner image at the transfer nip part is separated from the surface of the charged body, introduced into a toner image fixing unit (not shown), and fixed as a toner image and output as an image formed product. In the case of the double-sided image forming mode or the multiple image forming mode, the image formed product is introduced into a recirculation conveyance mechanism (not shown) and reintroduced into the transfer nip portion.

  Residues on the charged body 21 such as transfer residual toner are collected from the charged body by a cleaning means 26 such as a blade type.

  Further, from the viewpoint of image defects and the like, there are preferably 27 pre-exposure means if necessary. In the case where the staying charge remains on the charged body 21, it is better to remove the staying charge on the charged body 21 by the pre-exposure device 27 before performing the primary charging by the charging member 22.

  In addition, as an electrophotographic apparatus, a process cartridge in which a plurality of the above-described objects to be charged, a charging member, a developing member, a cleaning member, a toner, a toner container, a waste toner container, and the like are combined is combined with a copying machine or a laser beam. It may be configured to be detachable from an electrophotographic apparatus such as a printer. By using the process cartridge, it is possible to replace the members that are severely deteriorated at once, and to replenish the toner and collect the waste toner without scattering the toner.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not limited to the following. In the following, unless otherwise specified, commercially available high-purity products were used unless otherwise specified.

(Conductive elastic body 1)
NBR (trade name “Nipol (registered trademark) DN219” manufactured by Nippon Zeon Co., Ltd.) as a main rubber of the conductive elastic body 100 parts by mass, carbon black (trade name “Asahi HS-500” as conductive particles): Asahi Carbon) 14 parts by mass and carbon black (trade name “Ketjen Black EC600JD”: Lion) 4 parts by weight, zinc stearate 1 part by mass, zinc oxide 5 parts by mass, calcium carbonate (trade name “Nanox # 30” : Maruo Calcium Co., Ltd.) 20 parts by mass with a pressure kneader for 15 minutes, and dibenzothiazolyl disulfide (trade name “Noxeller (registered trademark) DM-P”: Ouchi Shinsei Chemical Co., Ltd.) 1 part by mass, tetrabenzylthiuram disulfide (trade name “Parcasit TBzTD”: manufactured by Flexis Co., Ltd.) 3 parts by mass, 1.2 parts by mass of sulfur as a vulcanizing agent, and added for 15 minutes. And the mixture was kneaded in Nroru.

  This kneaded composition was extruded into a cylindrical shape having an outer diameter of 10 mm and an inner diameter of 5.5 mm with a rubber extruder, cut into a length of 250 mm, and primary vulcanized with steam at 160 ° C. for 40 minutes in a vulcanizing can. A conductive elastic body primary vulcanization tube was obtained. Next, a hot melt adhesive was applied to the central portion 231 mm in the axial direction of the cylindrical surface of a cylindrical conductive support (steel surface industrial nickel plating) having a diameter of 6 mm and a length of 256 mm, and dried. The support was inserted into the conductive elastic body primary vulcanization tube, then placed in an electric oven, subjected to secondary vulcanization and adhesive curing at 160 ° C. for 1 hour to obtain an unpolished conductive member. . After cutting both ends of the rubber part of this unpolished product to make the length of the rubber part 231 mm, the rubber part is polished with a rotating grindstone, and the crown shape with an end diameter of 8.3 mm and a central part of 8.5 mm is used. An electrophotographic conductive member having a ten-point average roughness Rz of 3 μm and a deflection of 20 μm was obtained.

(Conductive elastic body 2)
Liquid epoxidized polybutadiene (trade name “Adekasizer (registered trademark) BF-1000” manufactured by Asahi Denka Kogyo Co., Ltd.) added to the conductive elastic body 1 at the time of kneading was used as the conductive elastic body 2. .

(Coating liquid 1)
A coating solution 1 was prepared by dissolving 5 parts by mass of silicone oil (trade name “SH28PA” manufactured by Toray Dow Corning Co., Ltd.) in 995 parts by mass of MIBK (methyl isobutyl ketone). When the viscosity of the coating liquid 1 was measured with a B-type viscosity type, it was 1 mPa · s or less.

(Coating solution 2)
Coating solution (trade name: SAT-500F; adjusted so that solid content of terminal isocyanate siloxane, polyester component, silane coupling agent and the like is about 2% by weight with respect to ethyl acetate / toluene (weight ratio 25/1). The coating solution 2 was Shinko Giken Co., Ltd. When the viscosity of the coating liquid 2 was measured with a B-type viscosity type, it was 1 mPa · s or less.

(Coating liquid 3)
90 parts by mass of a trifunctional acrylate monomer (trade name “SR-454” manufactured by Nippon Kayaku Co., Ltd.) and 10 parts by mass of a silane coupling agent (trade name “KBM-5103” manufactured by Shin-Etsu Chemical Co., Ltd.) A coating solution 3 was prepared by dissolving a radical type photopolymerization initiator (trade name “DAROCUR (registered trademark) 1173” manufactured by Ciba Specialty Chemicals) in 400 parts by mass of MIBK (methyl isobutyl ketone). When the viscosity of the coating liquid 3 was measured with a B-type viscosity type, it was 1 mPa · s or less.

(Coating solution 4)
Glycidoxypropyltriethoxysilane (GPTES) 27.84 g (0.1 mol), methyltriethoxysilane (MTES) 17.83 g (0.1 mol) and tridecafluoro-1,1,2,2-tetrahydrooctyltri 7.68 g of ethoxysilane (FTS, carbon number of perfluoroalkyl group 6) (0.0151 mol (equivalent to 7 mol% with respect to the total amount of hydrolyzable silane compound)), 17.43 g of water and 37.88 g of ethanol are mixed. Then, the mixture was stirred at room temperature and then heated to reflux for 24 hours to obtain an organic-inorganic hybrid sol.

  By adding this condensate to a 2-butanol / ethanol mixed solvent, an organic-inorganic hybrid sol-containing alcohol solution having a solid content of 7% by mass was prepared.

  0.35 g of an aromatic sulfonium salt (trade name: Adekaoptomer SP-150, manufactured by Asahi Denka Kogyo Co., Ltd.) as a photocationic polymerization initiator for 100 g of this organic-inorganic hybrid sol-containing alcohol solution The coating solution 4 was added to the hybrid sol-containing alcohol solution and diluted with a mixed solvent of 2-butanol / ethanol so that the solid content was 0.5% by mass. When the viscosity of the coating liquid 4 was measured with a B-type viscosity type, it was 1 mPa · s or less.

(Coating solution 5)
Carbon black (trade name “Toka Black (registered trademark) # 5500”: manufactured by Asahi Denka Kogyo Co., Ltd.) 30 parts by mass and the above coating solution 3 were mixed, and 200 parts of glass beads having a diameter of 0.8 mm were added thereto. The solution was put in a mayonnaise bin and dispersed for 6 hours using a paint shaker to make coating solution 5. When the viscosity of the coating liquid 5 was measured with a B-type viscosity type, it was 6.7 mPa · s or less.

  The coating liquid 1 was applied to the conductive elastic body 1 by ring coating. Then, using a low-pressure mercury lamp, the electrophotographic conductive member was irradiated uniformly with ultraviolet rays while rotating the conductive elastic body 1 so that the light intensity of the ultraviolet rays became 8000 mJ / cm 2 with a sensitivity of 254 nm sensor. Example 1 was adopted. A low-pressure mercury lamp manufactured by Harrison Toshiba Lighting Co., Ltd. was used for ultraviolet irradiation.

  An electrophotographic conductive member produced in the same manner as in Example 1 except that the coating liquid 2 was used instead of the coating liquid 1 in Example 1 was designated as Example 2.

  A conductive member for electrophotography was prepared in the same manner as in Example 1 except that the coating liquid 3 was used instead of the coating liquid 1 in Example 1.

  A conductive member for electrophotography is produced in the same manner as in Example 1 except that the conductive elastic body 2 is used instead of the conductive elastic body 1 of Example 1 and the coating liquid 4 is used instead of the coating liquid 1. This was designated as Example 3.

[Comparative Example 1]
Comparative Example 1 was obtained by producing a conductive member for electrophotography by the same method as Example 1 except that nothing was applied to conductive elastic body 1 and only ultraviolet rays were irradiated.

[Comparative Example 2]
Comparative Example 2 was prepared by producing a conductive member for electrophotography by the same method as in Example 1 except that ultraviolet rays were not irradiated after coating in Example 1.

[Comparative Example 3]
Comparative Example 3 was obtained by producing a conductive member for electrophotography by the same method as in Example 1 except that the coating liquid 5 was used instead of the coating liquid 1 in Example 1.

  The measurement conditions for each evaluation item are described below.

<Measurement of UV transmittance>
Each coating solution is applied to quartz glass and air-dried to volatilize the solvent. The quartz glass was set in the reference cell and the quartz glass on which the coating film was formed was set in the sample cell, and the ultraviolet-visible transmission spectrum was measured. The measurement conditions were UV-visible spectrophotometer V-570 (JASCO Corporation), bandwidth 1.0 nm, near infrared bandwidth 8.0 nm, response medium, measurement range 800-200 nm, data acquisition interval 1 nm, The measurement was performed at a scanning speed of 1000 nm / min and a repetition number of one.

  Moreover, it is the coating film apply | coated on the electrically conductive elastic body of the quartz glass which apply | coated the coating liquids 1-4 and each Example and a comparative example, and is a film | membrane of the state before volatilizing a solvent and irradiating an ultraviolet-ray The thickness was measured with an electron microscope.

Since the peak wavelength of the ultraviolet lamp used for the production of the electrophotographic conductive member is 254 nm, the “transmittance of the coating film on the quartz glass at 254 nm (FIG. 3)” (= T _A ) and “quartz glass”. _A film obtained by correcting the effect of the film thickness by the following formula from “film thickness of the upper coating film” (= d _A ) and “film thickness of the coating film on the conductive elastic body” (= d _B ) The “UV transmittance” (= T _B ) of the above coating film was used.

_{T B = 100- (100-T} A) x d B / d A
<Measurement of dynamic friction coefficient>
An example (outline) of the method for measuring the dynamic friction coefficient in the present invention is shown in FIG. This measurement method is a method suitable for the case where the measurement object has a roller shape, and is a method based on Euler's belt type. According to this method, the electrophotographic conductive member which is the measurement object and a predetermined angle (θ ) (The thickness is 100 μm, the width is 30 mm, and the length is 180 mm), one end is connected to the measurement unit (load meter) and the other end is connected to the weight W. In this state, when the conductive member is rotated at a predetermined direction and speed, when the force measured by the measurement unit is F (g) and the weight of the weight is W (g), the friction coefficient (μ) is Determined by the following formula;
μ = (1 / θ) ln (F / W)
An example of a chart obtained by this measurement method is shown in FIG. Here, the value immediately after rotating the electrophotographic conductive member is the force necessary to start the rotation, and after that, it is understood that the force is necessary to continue the rotation. The force at the point (that is, at time t = 0 seconds) was defined as the static friction force, and the average value in the time between 8 <t (seconds) ≦ 10 was defined as the dynamic friction force.

  As other measurement conditions, a polyester film (trade name “Lumirror (registered trademark) S10 # 100”: Toray Co., Ltd.) was used as the material of the belt, the load was 100 g, the rotation speed was 115 rpm, and the data accumulation interval was 100 times. Made in seconds. The dynamic friction coefficient was calculated from the dynamic friction force obtained under these conditions.

<Measurement of contact angle>
Using a contact angle meter CA-X ROLL type manufactured by Kyowa Interface Co., Ltd. and analysis software FAMAS, the contact angle θ with water on the surface of the electrophotographic conductive member of each example and comparative example was measured.

  Detailed measurement conditions of the contact angle θ are as follows.

Measurement: Droplet method (perfect circle fitting)
Liquid volume: 1 μl
Droplet recognition: Automatic Image processing: Algorithm-Non-reflective Image mode: Frame Threshold level: Automatic Average number of times: 5 times <Measurement of film thickness>
The electrophotographic conductive member of each Example and Comparative Example was cut out with a knife, and a sample obtained by depositing platinum by about 10 nm with a sputtering apparatus (JFC-1900 auto fine coater, manufactured by JEOL) was used as a sample. The sample was observed with a scanning electron microscope (JSM-5910, manufactured by JEOL), the film thickness of the coating film was measured at five points by measuring the distance between two points, and the average value was taken as the film thickness.

<Image evaluation>
《Bleed trace evaluation》
The electrophotographic conductive members obtained in the above Examples 1 to 4 and Comparative Examples 1 to 3 were brought into contact with the object to be charged by applying a load of 500 g to both ends of the conductive support, and the room temperature was 40 ° C. It was left in a constant temperature and humidity chamber with a humidity of 95% for 1 week. The electrophotographic conductive member and the member to be charged are taken out from the thermo-hygrostat, and the member to be charged is used in the electrophotographic apparatus LBP5500 (manufactured by Canon Inc.) of FIG. And a halftone image was output in an environment of a temperature of 23 ° C. and a humidity of 50% RH. Evaluate whether the halftone image has an image defect (exudation trace) in which the density of the image is different from that of the surrounding area at the circumference of the electrophotographic conductive member and the object to be charged, that is, the contact part. did. If the bleeding mark cannot be recognized on the image, A will appear on the first image, but if it cannot be confirmed after several sheets have passed, B, a clear bleeding mark will appear. Was recognized, C was evaluated. If it is B or higher, it is at a level where there is no practical problem.

《Durable dirt evaluation》
Using the electrophotographic conductive members obtained in Examples 1 to 4 and Comparative Examples 1 to 3 as a charging roller, the electrophotographic apparatus shown in FIG. 3 is LBP5500 (manufactured by Canon Inc.) and attached at a temperature of 30 ° C. An image output durability test was performed in an environment of 80% humidity. As test conditions, 6,000 continuous sheets were passed by the method described above. Moreover, the film thickness of the coating film after an endurance test was measured by the above-mentioned method. At this time, evaluation of dot-like or linear image defects (durable stains) due to toner or external additives fixed to the charging roller does not exist at all on the basis of the frequency of occurrence (A), very rarely exists (B) and a large amount (D) were evaluated in three stages. This durable stain is caused by adhesion of toner and external additives when the coefficient of dynamic friction is high and the adhesiveness is high and when the contact angle is low.

"Evaluation results"
In Example 1, since the transmittance of the coating film is as high as 95%, the surface of the conductive elastic body can be cross-linked, and thus the dynamic friction coefficient is as small as 0.17. Further, since the coating film is made of silicone oil, it is less oxidized by ultraviolet rays, and the contact angle shows a high value of 109 °.

  Since the crosslink density on the surface of the conductive elastic body is high, the Brownian motion of the molecule is restricted, and the path of the exuding substance is narrowed. In addition, since the contact angle is high, the affinity between the exuding substance in the elastic body and the coating film decreases, and the exuding substance does not easily pass through the coating film. Due to these effects, the migration rate of the exuding substance decreases, and the exuding substance does not come out. In addition, since the coefficient of friction of the surface is low and the contact angle is high, dirt hardly adheres during durable use. Detrimental effects at the time of film formation include that the viscosity of the coating solution is 1 mPa · s or less and the film thickness is very thin, 1 μm or less. No harmful effect on filming occurred.

  In Example 2, since the transmittance of the coating film is as high as 80%, the surface of the conductive elastic body can be crosslinked, and since the outermost coating film has an isocyanate group, the coating film can also be crosslinked at the same time. In addition, the coefficient of dynamic friction is as small as 0.23. Moreover, since the coating film contains polysiloxane, there is little oxidation by ultraviolet rays, and the contact angle shows a high value of 120 °. Compared with Example 1, since the coating film is also cross-linked, the migration of the exuding substance in the conductive elastic body to the member surface can be further suppressed.

  In Example 3, since the transmittance of the coating film is as high as 75%, the surface of the conductive elastic body can be crosslinked, and since the outermost coating film has an acrylate group, the coating film can also be crosslinked at the same time. In addition, the coefficient of dynamic friction is as small as 0.30. Moreover, since the coating film contains a silane coupling agent, there is little oxidation by ultraviolet rays, and the contact angle shows a high value of 110 °. Compared with Example 1, since the coating film is also cross-linked, the migration of the exuding substance in the conductive elastic body to the member surface can be further suppressed.

  In Example 4, since the transmittance of the coating film is as high as 97%, the surface of the conductive elastic body can be crosslinked, and at the same time, since the coating film has an epoxy group, the coating film can also be crosslinked at the same time. Further, since the conductive elastic body also has an epoxy group, the coating film and the conductive elastic body are chemically bonded by the epoxy group. Therefore, the dynamic friction coefficient is as small as 0.25. Moreover, since the coating film contains polysiloxane, oxidation by ultraviolet rays is small, and the contact angle shows a high value of 115 °. Since the adhesion between the coating film and the conductive elastic body is further increased as compared with Examples 1 to 3, the coating film is not scraped or peeled even during durable use. Therefore, the retention rate of the film thickness is high, and adhesion of durable dirt can be suppressed.

  In Comparative Example 1, since the elastic body is irradiated with ultraviolet rays as it is without using any coating liquid, the coefficient of dynamic friction becomes as small as 0.18, but the contact angle becomes as low as 78 ° due to the oxidation of the elastic body, oozes out and is durable. Both stains are worse than Example 1.

  In Comparative Example 2, the surface of the conductive elastic body is not crosslinked because it is not irradiated with ultraviolet rays after coating, and the contact angle is as large as 100 °, but the dynamic friction coefficient is as high as 0.5, and both exudation and durable dirt are examples. It is worse than 1.

  In Comparative Example 3, because carbon black is contained and the viscosity of the coating solution is high, the transmittance of ultraviolet rays is as low as 1% or less. However, since the coating liquid was dripped while still having a liquid property, it could not be used as an electrophotographic conductive member.

  Table 1 shows a summary of the material composition and evaluation results together with the above-described Examples and Comparative Examples.

It is the schematic which shows an example of the electrophotographic conductive member of this invention. It is the schematic which shows an example of the electrophotographic apparatus using the electroconductive electroconductive member of this invention. It is the schematic which shows the transmission spectrum of the coating liquid in this invention. It is the schematic which shows the example of a measurement of the dynamic friction coefficient of the electrophotographic conductive member in this invention. It is the schematic which shows the chart which measured the dynamic friction force of the electroconductive electroconductive member in this invention.

Explanation of symbols

1 Conductive member for electrophotography 11 Conductive support (shaft)
DESCRIPTION OF SYMBOLS 12 Conductive elastic body 13 Conductive elastic body modification part 13 Coating film 21 Electrophotographic photoreceptor (charged body)
22 Charging member (charging roller)
23 exposure means 24 development means 24a toner carrier 24b stirring member 24c toner regulating member 25 transfer means 26 cleaning means 27 pre-exposure means L laser light S1, S2 bias power supply P transfer material

Claims (3)

  It has a step of forming a coating film with an ultraviolet transmittance of 100% or less and 20% or more on the surface of the conductive elastic body, and a step of irradiating the coating surface with ultraviolet rays, and passes through the coating film when irradiated with ultraviolet rays. A method for producing a conductive member for electrophotography, characterized in that the surface of a conductive elastic body is cross-linked with ultraviolet light.   2. The electrophotographic conductive member according to claim 1, wherein the coating film is formed using a paint having at least one functional group selected from a double bond, an epoxy group, an acrylate group, and an isocyanate group. Manufacturing method.   The conductive elastic body containing an epoxy group is used for the conductive elastic body, and an organic-inorganic hybrid sol containing an epoxy group bonded to polysiloxane and a cationic polymerizable catalyst is used for the coating film. 2. A method for producing an electrophotographic conductive member according to 1.

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