JP2005155660A - Roller and electrophotography device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roller having less in permanent compression deformation resulting from long-abandoned pressure contact and superior in wear resistance in use. <P>SOLUTION: The roller comprises a foamed electric layer 10b. The foamed elastic layer 10b has short fibers 21 and resin particles 23 dispersed into a vulcanized rubber 22, and the short fibers 21 are firmly adhered to part of the resin particles 23. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is useful as a charging roller, a developing roller, a transfer roller, a cleaning roller, a paper feed roller, and the like used in an electrophotographic copying machine, an electrophotographic printer, an electrophotographic facsimile, an electrophotographic printing machine, and the like. The present invention relates to a semiconductive roller and an electrophotographic apparatus using the semiconductive roller.

  For convenience, the image forming apparatus shown in FIG. 3 will be described as an example. The image forming apparatus of this example is a transfer type electrophotographic apparatus.

  Reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member as an image carrier, which is rotationally driven at a predetermined peripheral speed (process speed) in the clockwise direction indicated by an arrow.

  Reference numeral 2 denotes a charging roller as a charging member, which is brought into pressure contact with the surface of the photosensitive member 1 with a predetermined pressing force. In the case of the apparatus of this example, the charging roller rotates following the rotation of the photosensitive member 1. A predetermined charging bias is applied to the charging roller 2 by a charging bias application circuit (not shown), and the peripheral surface of the rotating photoreceptor 1 is subjected to primary charging processing to a predetermined polarity potential.

  Target image information is exposed L (slit exposure, scanning exposure, etc.) to the primary charging process surface of the rotating photosensitive member 1 by an exposure device (not shown), and the surface of the rotating photosensitive member 1 corresponds to the target image information. An electrostatic latent image is formed.

  In the case of the apparatus of this example, the formed electrostatic latent image is developed as a toner image by the developing device 3 of the non-magnetic one-component developing system. Reference numeral 4 denotes a developing roller, and 5 denotes a toner application roller for the developing roller 4. A predetermined developing bias is applied to the developing roller 4 by a developing bias applying circuit (not shown).

  On the other hand, a transfer material P as a recording material is fed out from a paper feed cassette 6 by a paper feed roller 7 and is brought into pressure contact with the photosensitive member 1 with a predetermined pressing force through a transport roller 8 and a registration roller 9. The sheet is fed at a predetermined timing to a transfer portion N that is a pressure nip portion with the transfer roller 10T, and is nipped and conveyed by the transfer portion N.

  A predetermined transfer bias is applied to the transfer roller 10T at a predetermined timing by a transfer bias application circuit (not shown). Then, the toner images formed and supported on the surface of the rotary photosensitive member 1 are sequentially transferred to the surface side of the transfer material P sandwiched and conveyed by the transfer portion N by electrostatic force and pressing force.

  The transfer material P that has received the transfer of the toner image is separated from the surface of the photosensitive member 1 and is introduced into the fixing device 16 by the conveying device 15 to undergo a fixing process of the toner image. The paper is discharged to the paper discharge tray 18 as a print.

  The surface of the photoreceptor 1 after the transfer of the toner image to the transfer material P is physically and electrically cleaned by removing the residual toner by the cleaning roller 12 of the cleaning device 11 and by removing the discharge 14 by the discharge lamp 13. And repeatedly used for image formation.

In the electrophotographic apparatus as in the above example, as the charging roller 2, the developing roller 4, and the transfer roller 10T, a low-pressure material using a foam suitable for being used in pressure contact with the photosensitive drum to maintain the nip width is used. Hard rollers are used. However, if the same part is left in pressure contact for a long period of time, the elastic body may be permanently deformed, which may cause problems such as poor charging of the photosensitive member, poor frictional charging to the toner, and defective transfer. From such a viewpoint, as shown in Patent Document 1 below, it is known to increase the rigidity of the foam by mixing short fibers in the foam elastic body. Further, since these rollers are used in contact with the photoreceptor, dimensional changes may occur due to wear due to long-term use, and the original performance may not be exhibited. Therefore, it is known to improve the wear resistance by mixing elastic particles as shown in Patent Document 2 below.
JP-A-4-358825 JP 7-215556 A

  However, there is a problem that the short fibers mixed in to increase the rigidity fall off from the elastic body due to friction with the photoconductor during continuous operation, and in the case of the foam only containing elastic particles, there is a cell wall that comes into contact with the photoconductor when left under pressure for a long time. There was a problem that it was permanently deformed without returning to its original shape.

  In order to solve the above-mentioned problems, the object of the present invention is to relieve compression permanent deformation of a roller that is left for a long period of time and to have excellent wear resistance without causing short fibers to fall out of an elastic body even in long-term use. And providing an electrophotographic apparatus.

  According to the present invention for achieving the above object, in a roller mainly disposed in an electrophotographic apparatus and composed of a cored bar and a foamed elastic body, it is shorter than a foamed elastic body mainly composed of vulcanized rubber. A roller is provided in which fibers and resin particles are mixed, and a part of these short fibers and resin particles are firmly bonded.

  Here, since the short fiber is filled in the gap (cell wall) between the cells, the rigidity of the deformed portion is increased by pressing the roller on the photosensitive member, and the permanent compression deformation is suppressed. Setability is realized.

  Furthermore, since resin particles enter the local space where the short fibers of the cell wall cannot be mixed, it is possible to withstand local deformation of the cell wall on the roller surface. At this time, since the short fibers are firmly adhered to the resin particles, even if they are repeatedly subjected to a frictional force between the roller surface and the photoreceptor surface due to long-term use, the short fibers and the resin particles are prevented from falling off the roller. The

  From the above, it is possible to realize a roller that can suppress compression permanent deformation caused by leaving the roller for a long period of time and prevent the short fibers from falling off the roller surface due to friction during use.

  As a result, when the above roller is used as a charging roller, a developing roller, and a transfer roller of an electrophotographic apparatus, an image free from streaks and color unevenness can be maintained over a long period of time.

  The above-described configuration is shown again in the following (1) to (11).

  (1) A roller comprising a foamed elastic body in which short fibers and resin particles are dispersed on a core shaft.

  (2) The roller according to (1), wherein the average length of the short fibers is 0.05 mm or more and 5 mm or less, and the average fiber diameter is 0.1 μm or more and 50 μm or less.

  (3) The roller according to (1) or (2) above, wherein an average length of the short fibers is longer than an average cell diameter of the foam.

  (4) The roller according to any one of (1) to (3), wherein the short fiber is at least one selected from the group consisting of polyester monofilament, urethane monofilament, and polyamide monofilament.

  (5) The roller according to (1), wherein the resin particles have an average diameter of 0.1 μm or more and 50 μm or less.

  (6) The roller according to any one of (1) to (5), wherein the resin particles are at least one selected from the group consisting of polyester, urethane, and polyamide resin.

  (7) The roller according to any one of (1) to (6) above, wherein the foamed elastic layer contains an acid-modified olefin.

  (8) The roller as described in any one of (1) to (6) above, wherein the foamed elastic layer contains an epoxy-modified thermoplastic elastomer.

  (9) A roller having one or more layers on the roller surface as described in (1) above.

  (10) An electrophotographic apparatus, wherein the roller according to any one of (1) to (9) is disposed as a transfer roller.

  (11) An electrophotographic apparatus in which the roller according to any one of (1) to (9) is disposed as a developing roller.

  A roller characterized in that short fibers and resin particles are mixed in the foamed elastic body according to the present invention, and these short fibers and resin particles are firmly bonded. Is excellent.

  In particular, when used as a charging roller, a developing roller, and a transfer roller of an electrophotographic apparatus, an image defect does not occur even after being left for a long period of time, and a high-quality image is provided even after long-term use.

  FIG. 1 schematically shows a roller 10 according to the present invention. Reference numeral 10a denotes a cored bar made of a cylindrical conductive substrate, and the outer periphery thereof is formed from a foamed elastic layer 10b. Further, the surface layer 10c may be formed on the outer periphery of the foamed elastic layer 10b in consideration of the resistance adjustment of the entire roller 10, the triboelectric charging property of the toner, and the toner releasability depending on the application. The foamed elastic layer 10b is made of vulcanized rubber.

  FIG. 2 shows the details of the foamed elastic layer 10b. Short fibers 21 and resin particles 23 are dispersed in the vulcanized rubber 22 so that the rigidity of the 25 cell walls is increased. Here, 24 is a foam cell. Some of the short fibers 21 are bonded to the resin particles 23. Furthermore, some of the short fibers 21 may protrude into the cell.

  The vulcanized rubber 22 used in the present invention may be a general vulcanized rubber, such as a diene rubber and a hydrogenated product thereof (for example, NR, IR, epoxidized natural rubber, SBR, BR (high cis BR and low cis). BR), NBR, hydrogenated NBR, hydrogenated SBR), olefin rubber (eg ethylene propylene rubber (EPDM, EPM), maleic acid modified ethylene propylene rubber (M-EPM)), butyl rubber (IIR), isobutylene and aromatic Vinyl or diene monomer copolymer, acrylic rubber (ACM), halogen-containing rubber (for example, Br-IIR, Cl-IIR, bromide of isobutylene paramethylstyrene copolymer (Br-IPMS), chloroprene rubber (CR), Hydrin rubber (CHC, CHR), chlorosulfonated polyethylene (CSM), chlorinated polyethylene CM), maleic acid-modified chlorinated polyethylene (M-CM)), silicone rubber (for example, methyl vinyl silicone rubber, dimethyl silicone rubber, methyl phenyl vinyl silicone rubber), sulfur-containing rubber (for example, polysulfide rubber), fluoro rubber (for example, vinylidene fluoride) Ride rubbers, fluorine-containing vinyl ether rubbers, tetrafluoroethylene-propylene rubbers, fluorine-containing silicon rubbers, fluorine-containing phosphazene rubbers) and the like may be mentioned.

  Examples of the short fiber 21 to be blended include cellulose fiber, protein fiber, polyester fiber, polyamide fiber, acrylic fiber, polyolefin fiber, aramid fiber, urethane fiber, and carbon fiber. From the viewpoint of the bending rigidity of the short fibers 21 and the adhesion to the resin particles 23, polyester monofilaments, urethane monofilaments and polyamide monofilaments are preferable. Further, the volume resistance of these short fibers 21 is desirably 1E07 Ωcm or more. If it is less than 1E07 Ωcm, it becomes difficult to control the roller resistance.

  The resin particles 23 to be blended may be ordinary thermoplastic resins such as polyolefin resins (for example, polyethylene (PE) and polypropylene (PP)), polyamide resins (for example, nylon 6 (N6), nylon 66 (N66), Nylon 46 (N46), Nylon 11 (N11), Nylon 12 (N12), Nylon 610 (N610), Nylon 612 (N612), Nylon 6/66 copolymer (N6 / 66), Nylon 6/66/610 Polymer (N6 / 66/610), nylon MXD6, nylon 6T, nylon 6 / 6T copolymer, nylon 66 / PP copolymer, nylon 66 / PPS copolymer), polyester resin (for example, polybutylene terephthalate ( PBT), polyethylene terephthalate (PET), polyethylene isophthalate (PEI), polybutylene terephthalate / tetramethylene glycol copolymer, PET / PEI copolymer, polyarylate (PAR), polybutylene naphthalate (PBN), liquid crystal polyester, polyoxyalkylene diimide diacid / polybutylene terephthalate Aromatic polyesters such as copolymers), polynitrile resins (for example, polyacrylonitrile (PAN), polymethacrylonitrile, acrylonitrile / styrene copolymer (AS), methacrylonitrile / styrene copolymer, methacrylonitrile / styrene) / Butadiene copolymer), poly (meth) acrylate resin (for example, polymethyl methacrylate (PMMA), ethylene ethyl acrylate copolymer (EEA), ethylene acrylic acid copolymer (EAA), ethylene methyl Acrylate resin (EMA)), polyvinyl resins (for example, vinyl acetate (EVA), polyvinyl alcohol (PVA), vinyl alcohol / ethylene copolymer (EVOH), polyvinylidene chloride (PVDC), polyvinyl chloride (PVC), chloride) Vinyl / vinylidene chloride copolymer, vinylidene chloride / methyl acrylate copolymer), cellulose resin (for example, cellulose acetate, cellulose acetate butyrate), fluorine resin (for example, polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), A compound obtained by adding a compounding agent to polychlorofluoroethylene (PCTFE), tetrafluoroethylene / ethylene copolymer (ETFE)), an imide resin (for example, aromatic polyimide (PI)), or the like can be given. In order to make these resins fine particles, a physical pulverization method is used in which a polymer chip or powder is frozen and pulverized into a fine powder using a known pulverizer. Here, polyester, polyurethane and polyamide resin are preferable from the viewpoint of adhesiveness to short fibers.

  When the roller 10 requires electrical characteristics, conductive particles such as carbon black, zinc oxide, tin oxide, and titanium oxide can be dispersed in the vulcanized rubber 22 to control the specific volume resistivity. The acid-modified olefin or epoxy-modified thermoplastic elastomer mixed in the elastic layer 10b improves the adhesion between the short fibers 21 and the resin particles 23, and is an ethylene / acrylic acid ester / maleic anhydride terpolymer ( Specifically, Sumika Atchem Co., Ltd., trade name Bondain) and epoxidized styrene / butylene copolymer (specifically, Daicel Chemical Industries, trade name Epofriend) may be mentioned. The composition of the ethylene / acrylic acid ester / maleic anhydride terpolymer is preferably 2 to 5% by weight of maleic anhydride and 6 to 30% by weight of acrylic acid ester and has a melting point of 60 ° C. to 110 ° C. . The epoxidized styrene / butylene copolymer preferably has an epoxidation rate of 5% or more. If it is 5% or less, strong adhesion cannot be obtained between the short fibers 21 and the resin particles 23. The acid-modified olefin or epoxy-modified thermoplastic elastomer is melted in the matrix layer of the elastic body layer 10b and contributes to improving the adhesion between the short fibers and the resin. A sufficient effect can be obtained. The adhesive evaluation between the short fibers 21 and the resin particles 23 was made by cutting out the roller cross section with a cutter after making the roller, grasping the fibers protruding into the foam cell 24 with a tweezer-shaped jig, and pulling out the short fibers 21 from the elastic body. Then, by observing the extracted part with a microscope, the area ratio between the resin particle 23 adhered to the fiber and the part where the fiber surface is exposed is calculated, and the resin particle adhesion rate to the fiber is evaluated. . If the adhesion rate is 5% or more, a good adhesive force without dropping the short fibers 21 can be obtained.

  In order to use the vulcanized rubber composition obtained by the present invention as a foam, a foaming agent such as an inorganic salt, an organic compound or distilled water is used. Examples of inorganic salts include sodium hydrogen carbonate, ammonium hydrogen carbonate, ammonium carbonate and the like, and organic compounds include azodicarbonamide, azobisisobutyronitrile, dinitropentamethylenetetramine, 4,4'-oxybisbenzosulfonylhydrazide. And paratoluenesulfonyl hydrazide. These foaming agents need to be blended at a ratio of 0.5 to 15 parts with respect to 100 parts by weight of the thermoplastic elastomer. If the blending amount is less than 0.5 parts by weight, a desired foaming ratio cannot be obtained, and even if it is 15 parts or less, a foaming ratio sufficient for use can be obtained. Therefore, blending more than 15 parts is disadvantageous in terms of cost. Only.

  The elastic body layer 10b made of the vulcanized rubber 22 of the present invention is composed of rubber (for example, EPDM), conductive particles (for example, carbon black), vulcanizing agent, foaming agent, etc., short fibers 21 and resin particles 23, acid-modified olefin, It is formulated by adding an epoxy-modified thermoplastic elastomer, extruded, and heated to form a roller on the core 10a. Thereafter, the surface was polished to prepare a semiconductive elastic roller.

  When the surface layer is used, the surface layer 10c may be anything as long as it can be molded on the outer periphery of the elastic body layer 10b, but the rubber, resin, and / or thermoplastic elastomer component is desirable. What is necessary is just to form a surface layer using methods, such as dipping, spraying, and roll coating, for these.

  The metal core 10a may be any metal as long as it is made of metal, for example, SUS or aluminum.

  The average length of the short fibers 21 used in the roller 10 is 0.05 mm or more and less than 5 mm, and the average fiber diameter is preferably 0.1 μm or more and less than 50 μm. If the average length is less than 0.05 mm or the average fiber diameter is less than 0.1 μm, the rigidity that can resist the deformation at the time of press contact cannot be obtained, and the compression permanent deformability is deteriorated. If the average length is 5 mm or more or the average fiber diameter is 50 μm or more, the processability is poor and a dispersion failure tends to occur.

  In addition, the average length and average fiber diameter of the short fiber 21 can be calculated | required by measuring the length and fiber diameter of arbitrary 100 short fibers with a microscope, and averaging this.

  Furthermore, the average length of the short fibers 21 is preferably longer than the average cell diameter of the foam.

  If the length of the short fiber 21 is equal to or less than the average cell diameter, rigidity that can withstand deformation during pressure welding cannot be obtained.

  Here, the average cell diameter can be obtained by observing an arbitrary cross section with an SEM, measuring arbitrary 100 cell diameters, and averaging these.

  Moreover, it is preferable that the volume fraction which the short fiber 21 occupies for the elastic body layer 10b is 1% or more and less than 50% from a viewpoint of set property. In particular, by setting the volume fraction to 1% or more, the recovery after leaving for long-term pressure contact is also good. If it is 50% or more, the workability becomes worse.

  The average diameter of the resin particles 23 used in the roller 10 is preferably 0.1 μm or more and less than 50 μm. If the average diameter is less than 0.1 μm, the rigidity that can resist the deformation at the time of pressure welding cannot be obtained, and the compression permanent deformability is deteriorated. When the average diameter is 50 μm or more, processability is poor and dispersion failure tends to occur.

  The average diameter of the resin particles 23 can be measured using a particle size distribution measuring device (Sald-7000, Shimadzu Corporation).

  Moreover, it is preferable that the volume fraction which the resin particle 23 occupies for the elastic body layer 10b is 1% or more and less than 50% from a viewpoint of set property. In particular, by setting the volume fraction to 1% or more, the recovery after leaving for long-term pressure contact is also good. If it is 50% or more, the workability becomes worse.

  The volume fraction of the resin particles 23 in the elastic body layer 10b refers to an arbitrary cross section of the roller 10 observed with an electron microscope, and the elastic body layer 10b of any 100 resin particles 23 observed in the cross section. The volume ratio of the resin particles 23 occupying the entire elastic body layer 10b is calculated by measuring the area of the portion existing in the surface.

  Next, examples of the present invention will be described.

(Example 1)
As shown in Table 1, a polyester monofilament (Tetron made by Teijin) with a cut length of 2 mm and an average fiber diameter of 10 μm and fine particles adjusted to an average particle diameter of 10 μm by freezing and pulverizing them to EPDM (Esplen EPR505 manufactured by Sumitomo Chemical) Further, carbon black as a resistance control agent and azodicarbonamide as a foaming agent were blended and adjusted to a semiconductive rubber and formed into a tube shape. The vulcanized rubber is blended in 35 parts by weight of polyester monofilament, 100 parts by weight of EPDM, 2 parts by weight of a foaming agent azodicarbonamide (Binhole AC manufactured by Eiwa Kasei), 25 parts by weight of carbon black (Chiest 3 Tokai Carbon Co., Ltd.), zinc white 5 parts (trade name Sazex, manufactured by Sakai Chemical Industry Co., Ltd.), 1 part stearic acid (manufactured by Asahi Denka Co., Ltd.), vulcanization accelerator (trade name: Noxeller M, Noxeller TRA, Ouchi Shinsei Co., Ltd.) 1.2 parts of sulfur (trade name: Sulfax PMC, manufactured by Tsurumi Chemical Co., Ltd.) and process oil (trade name: PW-380, manufactured by Idemitsu Kosan Co., Ltd.) were used. These were used to form a tube having an inner diameter of 7.5 mm and a wall thickness of 4 mm using an extruder. The tube was coated on a core metal having a diameter of 8 mm, vulcanized under predetermined conditions, and the surface was polished to form a foamed elastic layer having a thickness of 4 mm to produce a semiconductive roller having a volume resistance of 1.0E8 Ωcm.

(Example 2)
The short fiber in Example 1 is a nylon 6 monofilament (Amilan manufactured by Toray) having a cut length of 2 mm and an average fiber diameter of 10 μm, and 25 parts by weight of nylon fine particles having an average particle diameter of 5 μm (SP-500 manufactured by Toray) in the formulation of Example 1. Further, a semiconductive roller having a volume resistance of 1.0E8 Ωcm was produced in the same manner as in Example 1 except that 5 parts by weight of acid-modified olefin (Bondyne AX8390 manufactured by Sumika Atchem) was added.

(Example 3)
The short fibers in Example 1 were polyurethane monofilaments (Espa manufactured by Toyobo Co., Ltd.) having a cut length of 2 mm and an average fiber diameter of 10 μm, and urethane fine particles having an average particle diameter of 6 μm (Art Pearl C-800 manufactured by Negami Kogyo Co., Ltd.) 25 A semiconductive roller having a volume resistance of 1.0E8 Ωcm was prepared in the same manner as in Example 1 except that 5 parts by weight of epoxy modified thermoplastic elastomer (Epofriend A1010 manufactured by Daicel Chemical Industries) was added.

(Comparative Example 1)
As shown in Table 1, nylon 6 monofilament (Amilan manufactured by Toray) with a cut length of 2 mm and an average fiber diameter of 10 μm is dispersed in EPDM (Esplen EPR505 manufactured by Sumitomo Chemical), and further, carbon black as a resistance control agent and azo as a foaming agent. A compound prepared by mixing dicarbonamide and preparing a semiconductive rubber was formed into a tube shape. The composition of the vulcanized rubber is 35 parts by weight of nylon 6 monofilament with respect to 100 parts by weight of EPDM, 2 parts by weight of foaming agent azodicarbonamide (Binole AC manufactured by Eiwa Kasei), 25 parts by weight of carbon black (Seast 3, manufactured by Tokai Carbon Co., Ltd.) Zinc flower 5 parts (trade name Sazex Sakai Chemical Industry Co., Ltd.), stearic acid 1 part (Asahi Denka Co., Ltd.), vulcanization accelerator (trade name Noxeller M, Noxeller TRA Ouchi Shinsei Co., Ltd.) 0.8 parts each Each was 1.2 parts of sulfur (trade name: Sulfax PMC, manufactured by Tsurumi Chemical Co., Ltd.) and process oil (trade name: PW-380, manufactured by Idemitsu Kosan Co., Ltd.). These were used to form a tube having an inner diameter of 7.5 mm and a wall thickness of 4 mm using an extruder. The tube was coated on a core metal having a diameter of 8 mm, vulcanized under predetermined conditions, and the surface was polished to form a foamed elastic layer having a thickness of 4 mm to produce a semiconductive roller having a volume resistance of 1.0E8 Ωcm.

(Comparative Example 2)
As shown in Table 1, nylon fine particles (SP-500 made by Toray) having a cut length of 2 mm and an average particle diameter of 5 μm are dispersed in EPDM (Esplen EPR505 manufactured by Sumitomo Chemical Co., Ltd.), and further, carbon black and foaming agent as resistance control agents A mixture of azodicarbonamide and adjusted to semiconductive rubber was formed into a tube shape. Vulcanized rubber is blended in 100 parts by weight of EPDM with 25 parts by weight of nylon fine particles, 2 parts by weight of blowing agent azodicarbonamide (Binole AC manufactured by Eiwa Kasei), 25 parts by weight of carbon black (Shiest 3 Tokai Carbon Co., Ltd.), zinc white 5 parts (trade name Sazex, manufactured by Sakai Chemical Industry Co., Ltd.), 1 part stearic acid (manufactured by Asahi Denka Co., Ltd.), vulcanization accelerator (trade name: Noxeller M, Noxeller TRA, Ouchi Shinsei Co., Ltd.) Sulfur 1.2 parts (trade name Sulfax PMC, manufactured by Tsurumi Chemical Co., Ltd.) and process oil (trade name PW-380, manufactured by Idemitsu Kosan Co., Ltd.) were used. These were used to form a tube having an inner diameter of 7.5 mm and a wall thickness of 4 mm using an extruder. The tube was coated on a core metal having a diameter of 8 mm, vulcanized under predetermined conditions, and the surface was polished to form a foamed elastic layer having a thickness of 4 mm to produce a semiconductive roller having a volume resistance of 1.0E8 Ωcm.

  The roller was mounted as a transfer roller of the image forming apparatus shown in FIG. 3 so that the nip width with the photosensitive drum was 1 mm, and a pressure contact test was conducted for 3 months.

  After standing, a solid black image formation test using A4 size paper was performed, and initial images were evaluated.

  In the case where the short fibers are dispersed in the foamed elastic layer as in Examples 1 to 3, a good image was obtained without generation of streaks, whereas in Comparative Examples 1 and 2, the period per rotation of the roller There was a streak that matched Further, when these rollers were removed from the photosensitive drum and visually observed after pressure contact, there was no problem in the examples, but pressure contact marks remained in the longitudinal direction of the rollers in Comparative Examples 1 and 2. Next, a continuous sheet passing test was performed using the same apparatus, and the number of sheets to be passed until the roller surface wear amount reached 50 μm was evaluated. As a result, Example 1 was 300K or more, and Examples 2 and 3 were 500K. The wear amount of the sheets was less than 50 μm, whereas in Comparative Examples 1 and 2, the wear amount reached 50 μm at 200 k.

Example 4
As shown in Table 2, polyester monofilament (Tetron manufactured by Teijin) with a cut length of 2 mm and an average fiber diameter of 10 μm is dispersed in EPDM (Esplen EPR505 manufactured by Sumitomo Chemical Co., Ltd.), and carbon black as a resistance control agent and azodicarbon as a foaming agent. An amide compounded into a semiconductive rubber was formed into a tube shape. The vulcanized rubber was compounded in 100 parts by weight of EPDM, 35 parts by weight of polyester monofilament, 2 parts by weight of blowing agent azodicarbonamide (Binhole AC, manufactured by Eiwa Kasei), 25 parts by weight of carbon black (Seast 3, manufactured by Tokai Carbon Co., Ltd.), zinc Hana 5 parts (trade name Sazex, manufactured by Sakai Chemical Industry Co., Ltd.), stearic acid 1 part (manufactured by Asahi Denka Co., Ltd.), vulcanization accelerator (trade name Noxeller M, Noxeller TRA Ouchi Shinsei Co., Ltd.) 0.8 parts each Each was 1.2 parts of sulfur (trade name: Sulfax PMC, manufactured by Tsurumi Chemical Co., Ltd.) and process oil (trade name: PW-380, manufactured by Idemitsu Kosan Co., Ltd.). These were used to form a tube having an inner diameter of 7.5 mm and a wall thickness of 4 mm using an extruder. The tube was coated on a core metal of φ8 mm, vulcanized under predetermined conditions, and the surface was polished to form a foamed elastic layer having a thickness of 4 mm. Next, after the surface of the elastic layer is UV-treated, a polyether-based polyurethane (trade name Superflex 460, manufactured by Daiichi Kogyo Seiyaku) is used to make a 40% aqueous solution, and carbon black (trade name Seast 3) is used for resistance adjustment. , Manufactured by Tokai Carbon Co., Ltd.), 40 parts of 100 parts of polyurethane are mixed with a roll coater and heated and cured at 120 ° C. for 20 minutes to form a surface layer having a thickness of 20 μm. A 0E8 Ωcm multilayer roller was produced.

(Example 5)
The short fiber in Example 4 is a nylon 6 monofilament (Amilan manufactured by Toray) having a cut length of 2 mm and an average fiber diameter of 10 μm, and 25 parts by weight of nylon fine particles (SP-500 manufactured by Toray) having an average particle diameter of 5 μm in the formulation of Example 1. Further, a foamed elastic layer was formed in the same manner as in Example 4 except that 5 parts by weight of acid-modified olefin (Bondyne AX8390 manufactured by Sumika Atchem) was added.

  Next, using a copolymerized polyamide resin (copolymerized nylon, trade name: CM4000, manufactured by Toray Industries, Inc.), a 20% methanol solution is made, and carbon black (trade name: CAST3, manufactured by Tokai Carbon Co., Ltd.) is used as a polyamide resin for resistance adjustment. What mixed 40 parts with respect to 100 parts was apply | coated to the surface of the elastic layer obtained above by the dip method. This was air-dried and then dried at 80 ° C. to form a surface layer having a thickness of 20 μm, and a volume resistance 1.0E8Ωcm multilayer roller was produced.

(Example 6)
The short fiber in Example 5 is a polyurethane monofilament (Tospa Boes Espa) with a cut length of 2 mm and an average fiber diameter of 10 μm, and urethane fine particles with an average particle diameter of 6 μm (Art Pearl C-800, manufactured by Negami Kogyo Co., Ltd.) 25 A foamed elastic layer was formed in the same manner as in Example 5 except that 5 parts by weight of an epoxy-modified thermoplastic elastomer (Epofriend A1010 manufactured by Daicel Chemical Industries) was added.

  Next, after the surface of the elastic layer is UV-treated, a polyether-based polyurethane (trade name Superflex 460, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is used on the surface of the elastic layer to make a 40% aqueous solution. A black coat (trade name 3 manufactured by Tokai Carbon Co., Ltd.) mixed with 40 parts of 100 parts of polyurethane is coated with a roll coater and heated and cured at 120 ° C. for 20 minutes to form a surface layer having a thickness of 20 μm. Thus, a volume resistance 1.0E8 Ωcm multilayer roller was produced.

(Comparative Example 3)
As shown in Table 2, nylon 6 monofilament (Amilan manufactured by Toray) having a cut length of 2 mm and an average fiber diameter of 10 μm is dispersed in EPDM (Esplen EPR505 manufactured by Sumitomo Chemical), and further, carbon black as a resistance control agent and azo as a foaming agent. A compound prepared by mixing dicarbonamide and preparing a semiconductive rubber was formed into a tube shape. The vulcanized rubber was compounded in 100 parts by weight of EPDM with 35 parts by weight of nylon 6 monofilament, 2 parts by weight of a foaming agent azodicarbonamide (Binhole AC manufactured by Eiwa Kasei), 25 parts by weight of carbon black (Shiest 3 Tokai Carbon Co., Ltd.), zinc Hana 5 parts (trade name Sazex manufactured by Sakai Chemical Industry Co., Ltd.), stearic acid 1 part (manufactured by Asahi Denka Co., Ltd.), vulcanization accelerator (trade names Noxeller M, Noxeller TRA Ouchi Shinsei Co., Ltd.) 0.8 parts each And 1.2 parts of sulfur (trade name: Sulfax PMC, manufactured by Tsurumi Chemical Co., Ltd.) and process oil (trade name: PW-380, manufactured by Idemitsu Kosan Co., Ltd.). These were used to form a tube having an inner diameter of 7.5 mm and a wall thickness of 4 mm using an extruder. The tube was covered on a core metal of φ8 mm, vulcanized under predetermined conditions, and the surface was polished to form a foamed elastic layer having a thickness of 4 mm.

  The short fiber in Example 4 is a nylon 6 monofilament (Amilan manufactured by Toray) having a cut length of 2 mm and an average fiber diameter of 10 μm, and 25 parts by weight of nylon fine particles (SP-500 manufactured by Toray) having an average particle diameter of 5 μm in the formulation of Example 1. Further, a foamed elastic layer was formed in the same manner as in Example 4 except that 5 parts by weight of acid-modified olefin (Bondyne AX8390 manufactured by Sumika Atchem) was added.

  Next, using a copolymerized polyamide resin (copolymerized nylon, trade name: CM4000, manufactured by Toray Industries, Inc.), a 20% methanol solution is prepared, and carbon black (trade name: Seast 3 manufactured by Tokai Carbon Co., Ltd.) is added to the polyamide resin 100 for resistance adjustment. What mixed 40 parts with respect to the part was apply | coated to the surface of the elastic layer obtained above by the dip method. This was air-dried and then dried at 80 ° C. to form a surface layer having a thickness of 20 μm, and a volume resistance 1.0E8Ωcm multilayer roller was produced.

(Comparative Example 4)
As shown in Table 2, nylon fine particles (SP-500 made by Toray) having a cut length of 2 mm and an average particle size of 5 μm are dispersed in EPDM (Esplen EPR505, manufactured by Sumitomo Chemical Co., Ltd.), and further, carbon black and foaming agents as resistance control agents. A mixture of azodicarbonamide and adjusted to semiconductive rubber was formed into a tube shape. Vulcanized rubber is blended in 100 parts by weight of EPDM with 25 parts by weight of nylon fine particles, 2 parts by weight of blowing agent azodicarbonamide (Binole AC manufactured by Eiwa Kasei Co., Ltd.), 25 parts by weight of carbon black (Seast 3, manufactured by Tokai Carbon Co., Ltd.), zinc Hana 5 parts (trade name Sazex manufactured by Sakai Chemical Industry Co., Ltd.), stearic acid 1 part (manufactured by Asahi Denka Co., Ltd.), vulcanization accelerator (trade names Noxeller M, Noxeller TRA Ouchi Shinsei Co., Ltd.) 0.8 parts each 1.2 parts of sulfur (trade name: Sulfax PMC, manufactured by Tsurumi Chemical Co., Ltd.) and process oil (trade name: PW-380, manufactured by Idemitsu Kosan Co., Ltd.). These were used to form a tube having an inner diameter of 7.5 mm and a wall thickness of 4 mm using an extruder. The tube was covered on a core metal of φ8 mm, vulcanized under predetermined conditions, and the surface was polished to form a foamed elastic layer having a thickness of 4 mm.

  Next, using a copolymerized polyamide resin (copolymerized nylon, trade name: CM4000, manufactured by Toray Industries, Inc.), a 20% methanol solution was made, and carbon black (trade name: Seast 3; manufactured by Tokai Carbon Co., Ltd.) was added to the polyamide resin for resistance adjustment. What mixed 40 parts with respect to 100 parts was apply | coated to the surface of the elastic layer obtained above by the dip method. This was air-dried and then dried at 80 ° C. to form a surface layer having a thickness of 20 μm, and a volume resistance 1.0E8Ωcm multilayer roller was produced.

  The multi-layer roller was mounted on the developing device of the image forming apparatus shown in FIG. 3 so that the nip width with respect to the photosensitive drum was 1 mm, and a pressure contact leaving test for 3 months was performed. After standing, a solid black image formation test using A4 size paper was performed to evaluate the initial image. In this embodiment, the developing device 2 uses a non-magnetic one-component developing method. The developing container 3 contains a non-magnetic one-component toner. Further, the developing container 3 removes the remaining toner without being developed on the developer carrying body 4 and returns it to the developing container. The foamed urethane sponge roller 5 to be supplied is mounted.

  In Examples 4 to 6, good images were obtained without generation of streaks, whereas in Comparative Examples 3 to 4, streaks that coincided with the period of each rotation of the roller were generated. Moreover, when these rollers were removed from the photosensitive drum and visually observed after press contact, there was no problem in the examples, but in Example 3-4, press marks remained in the longitudinal direction of the rollers.

Typical sectional drawing for demonstrating the structural example of the roller of this invention Schematic enlarged view for explaining the existence state of short fibers Schematic sectional view for explaining a structural example of an electrophotographic apparatus

Explanation of symbols

1 Electrophotographic photoreceptor (rotating photoreceptor)
2 charging roller 3 developing device 4 developing roller 5 toner application roller 6 paper feed cassette 7 paper feed roller 8 transport roller 9 registration roller 10 roller 10a cored bar 10b foamed elastic layer 10c surface layer 10T transfer roller 11 cleaning device 12 cleaning roller 13 static elimination Lamp 14 Static elimination exposure 15 Transport device 16 Fixing device 17 Paper discharge roller 18 Paper discharge tray 21 Short fiber 22 Vulcanized rubber 23 Resin particles 24 Cell 25 Cell wall

Claims (11)

  A roller comprising a foamed elastic body in which short fibers and resin particles are dispersed on a core shaft.   The roller according to claim 1, wherein an average length of the short fibers is 0.05 mm or more and 5 mm or less, and an average fiber diameter is 0.1 μm or more and 50 μm or less.   The roller according to claim 1, wherein an average length of the short fibers is longer than an average cell diameter of the foam.   The roller according to any one of claims 1 to 3, wherein the short fiber is at least one selected from the group consisting of a polyester monofilament, a urethane monofilament, and a polyamide monofilament.   The roller according to claim 1, wherein an average diameter of the resin particles is 0.1 μm or more and 50 μm or less.   The roller according to claim 1, wherein the resin particles are at least one selected from the group consisting of polyester, urethane, and polyamide resin.   The roller according to any one of claims 1 to 6, wherein the foamed elastic layer contains an acid-modified olefin.   The roller according to claim 1, wherein the foamed elastic layer contains an epoxy-modified thermoplastic elastomer.   A roller having a layer comprising one or more layers on the surface of the roller according to claim 1.   An electrophotographic apparatus, wherein the roller according to claim 1 is disposed as a transfer roller.   10. An electrophotographic apparatus, wherein the roller according to claim 1 is disposed as a developing roller.

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