JP2005352015A - Developing roller and image forming apparatus provided with same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing roller which eliminates the need for a long drying line for mass production and the need for a polish process for an elastic layer, has proper minute irregularities on the surface of a resin layer, whose surface is hardly worn even when it is used for a long period of time, and which has excellent durability. <P>SOLUTION: The developing roller 1 includes: a shaft 2; an elastic layer 3 formed along the external circumference of the shaft 2; and an elastic layer 4 formed from at least one layer on the peripheral face of the elastic layer 3 and cured by UV irradiation and electron beam irradiation. In the developing roller 1, the resin layer 4 contains particles 5 dispersed in it, the maximum particle diameter a of each fine particle 5 to the thickness b of the resin layer 4, a/b, is 1.0 to 5.0, and the resin layer 4 contains fluorine. Additionally, in the developing roller 1, it is preferable that the average particle diameter of each fine particle 5 be 1 to 30μm, the particle diameter distribution of the fine particles 5 be 1 to 50μm, and the content of the fine particles 5 be 0.1 to 100 parts by mass to 100 parts by mass of the resin of the resin layer 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a developing roller and an image forming apparatus provided with the developing roller, and more particularly to a developing roller used in an electrophotographic apparatus such as a copying machine and a printer, and an image forming apparatus such as an electrostatic recording apparatus.

  In an electrophotographic image forming apparatus such as a copying machine or a printer, as a developing method for visualizing a latent image by supplying toner to a photosensitive drum or the like holding a latent image and attaching the toner to the latent image on the photosensitive drum. A pressure development method is known. In the pressure development method, for example, after the photosensitive drum is charged to a constant potential, an electrostatic latent image is formed on the photosensitive drum by an exposure machine, and further, a developing roller carrying toner is placed on the electrostatic latent image. Development is performed by bringing the toner into contact with the latent image on the photosensitive drum in contact with the held photosensitive drum.

  In the above pressure development method, the developing roller must rotate while securely holding the state in close contact with the photosensitive drum. Therefore, silicone rubber, acrylonitrile-butadiene are placed on the outer periphery of the shaft made of a highly conductive material such as metal. Semiconductive elastic body in which carbon black or metal powder is dispersed in an elastomer such as rubber (NBR), ethylene-propylene-diene rubber (EPDM), epichlorohydrin rubber (ECO), polyurethane or the like, and a foam in which these are foamed It has a structure in which a semiconductive elastic layer made of is formed. In addition, a resin layer may be further formed on the surface of the elastic layer for the purpose of controlling the chargeability and adhesion to the toner and preventing the photosensitive drum from being contaminated by the elastic layer.

  Conventionally, the resin layer is formed by dipping the developing roller in a solvent-based or aqueous coating solution or spraying the coating solution on the developing roller, followed by drying and curing with heat or hot air. Since long drying is required, a long drying line is necessary for mass production. In addition, the resin layer requires delicate conductivity and surface condition depending on its use, but the quality distribution problem is affected by variations in temperature distribution and air volume in the dry operation line, which greatly affects the performance of the resin layer. was there. On the other hand, as a method of forming a stable quality resin layer without requiring a long drying line, a resin is cured by applying a compound that becomes a resin layer by curing with ultraviolet irradiation on the surface of the elastic layer of the developing roller. A technique for forming a layer has been proposed (see Patent Document 1).

JP 2002-310136 A

  By the way, it is preferable that the developing roller can uniformly hold a predetermined amount of toner on the roller surface. Here, the amount of toner held on the roller surface is mainly determined by the electric force resulting from the charge of the charged toner and the unevenness of the roller surface. Therefore, it is possible to ensure excellent development characteristics by controlling the minute unevenness on the surface of the developing roller and adjusting the toner conveyance amount of the developing roller. Conventionally, in the development of the developing roller, since the base material was polished into a roller shape, the polishing surface had fine unevenness and a resin layer was formed thereon, so the resin layer also had appropriate minute unevenness Had. On the other hand, in order to omit the polishing process and improve the productivity of the developing roller, a technique for injecting the raw material of the elastic layer into the mold in which the shaft is arranged to produce the roller body is known. There has been a problem that the outer peripheral surface of the elastic layer becomes smooth like the cavity surface of the mold, and the resin layer formed thereon becomes smooth.

  In addition, since the developing roller formed by applying a compound that is cured by ultraviolet irradiation to the outer peripheral surface of the elastic layer and curing it to form a resin layer has a large frictional resistance on the roller surface, the roller surface is likely to be worn depending on use conditions. There was a problem. Therefore, when an image forming apparatus incorporating such a developing roller is used for a long time, there is a problem that the surface of the developing roller is scraped and image defects are likely to occur.

  Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, does not require a long drying line for mass production, does not require an elastic layer polishing step, and has a resin layer with moderate micro unevenness on the surface, and is long. An object of the present invention is to provide a developing roller that is hard to be scraped over time and has excellent durability. Another object of the present invention is to provide an image forming apparatus provided with such a developing roller and capable of stably forming a good image over a long period of time.

  As a result of intensive studies to achieve the above object, the present inventors have identified a compound that becomes a resin layer by being cured by ultraviolet irradiation or electron beam irradiation in a developing roller having a resin layer disposed on the surface of the elastic layer. By dispersing the fine particles having the maximum diameter of 5% and containing fluorine in the resin layer and forming the resin layer by ultraviolet irradiation or electron beam irradiation, a long drying line is unnecessary for mass production, and the temperature in the drying line Dispersion of the performance of the resin layer due to variations in distribution and air flow can be eliminated, the resin layer has moderate fine irregularities on the surface, and the frictional resistance of the roller surface is low so that the surface can be used even for a long time. The inventors have found that a developing roller that is less likely to wear is obtained, and have completed the present invention.

That is, the developing roller of the present invention includes a shaft, an elastic layer formed on the outer periphery of the shaft, and a resin layer formed on the outer peripheral surface of the elastic layer and cured by ultraviolet irradiation or electron beam irradiation. In the developing roller with
Fine particles are dispersed and contained in the resin layer, the ratio a / b between the maximum particle diameter a of the fine particles and the thickness b of the resin layer is 1.0 to 5.0, and the resin layer contains fluorine. Features. Here, the thickness b of the resin layer refers to the average thickness of the resin layer of the developing roller cured by ultraviolet irradiation or electron beam irradiation. The average thickness is an average value of the layer thicknesses at 10 locations. The layer thickness was measured by cutting a developing roller provided with a surface layer and using a microscope.

  In the developing roller of the present invention, it is preferable that the resin layer cured by ultraviolet irradiation or electron beam irradiation is heated after ultraviolet irradiation or electron beam irradiation to cure the remaining unreacted compound. In this case, it is possible to reliably prevent the unreacted compound from remaining in the resin layer.

  In the developing roller of the present invention, it is also preferable to cure the remaining unreacted compound by microwave heating the resin layer cured by ultraviolet irradiation or electron beam irradiation after ultraviolet irradiation or electron beam irradiation. Also in this case, it is possible to reliably prevent the unreacted compound from remaining in the resin layer.

  In the developing roller of the present invention, the average particle size of the fine particles is preferably 1 to 30 μm, the particle size distribution of the fine particles is preferably in the range of 1 to 50 μm, and the content of the fine particles is It is preferable that it is 0.1-100 mass parts with respect to 100 mass parts of resin of a resin layer.

  In another preferred embodiment of the developing roller of the present invention, the thickness b of the resin layer is preferably 1 to 40 μm. In this case, it is possible to prevent the charging roller surface from being deteriorated due to friction while preventing the developing roller surface from becoming too hard.

  In another preferred embodiment of the developing roller of the present invention, the fine particles are fine particles of rubber or synthetic resin or glassy carbon fine particles. Here, the rubber or synthetic resin fine particles include silicone rubber fine particles, silicone resin fine particles, fluororesin fine particles, urethane elastomer fine particles, urethane acrylate fine particles, melamine resin fine particles, phenol resin fine particles, (meth) acrylic resin fine particles, and styrene-based fine particles. Resin fine particles are preferred.

  In another preferred embodiment of the developing roller of the present invention, the resin layer contains a conductive agent. In this case, the electrical resistance of the resin layer can be reduced to improve the development characteristics. Here, it is preferable that content of this electrically conductive agent is 0.01-20 mass parts with respect to 100 mass parts of resin of the said resin layer.

  In another preferred embodiment of the developing roller of the present invention, the elastic layer is formed in a mold, and it is not necessary to polish the outer peripheral surface of the elastic layer. Further, after the formation of the elastic layer, the resin layer can be directly formed on the outer peripheral surface of the elastic layer. Even if the elastic layer is smooth, the developing roller of the present invention can hold a predetermined amount of toner uniformly on the roller surface because the resin layer has moderate minute irregularities.

  The image forming apparatus of the present invention includes the developing roller.

  According to the present invention, in a developing roller in which a resin layer cured by ultraviolet ray irradiation or electron beam irradiation is disposed on the surface of the elastic layer, fine particles having a specific maximum diameter are dispersed and contained in the resin layer and the resin layer is dispersed. By including fluorine in the layer, a long drying line is not required for mass production, the resin layer has moderate fine irregularities on the surface, the surface is difficult to wear even after long use, and the development roller has excellent durability Can be provided. Further, it is possible to provide an image forming apparatus that includes such a developing roller and can stably form a good image over a long period of time.

  Hereinafter, the developing roller of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of an example of the developing roller of the present invention. The developing roller 1 in the illustrated example includes a shaft 2, an elastic layer 3 formed on the outer periphery of the shaft 2, and a resin layer 4 formed on the outer peripheral surface of the elastic layer 3. Here, the resin layer 4 includes fine particles 5 and a fluorine-containing compound, and is cured by ultraviolet irradiation or electron beam irradiation.

  In the developing roller 1 of the present invention, since the resin layer 4 contains the fine particles 5, fine irregularities can be appropriately formed on the surface of the resin layer 4 by appropriately adjusting the concentration and particle size of the fine particles 5. A predetermined amount of toner can be uniformly held on the outer peripheral surface. More specifically, as described above, the purpose of dispersing the fine particles 5 in the resin layer 4 is to impart desired irregularities on the surface in order to improve the toner carrying property of the outermost surface of the developing roller 1. If the thickness of the resin layer 4 is larger than the particle size of the dispersed fine particles 5, the surface of the resin layer 4 may not be sufficiently uneven. The present inventors paid attention to this point, and as a result of earnest research, the inventors succeeded in providing the most uneven surface for toner carrying on the outermost surface of the developing roller 1 and completed the present invention.

  Specifically, if the maximum diameter of the fine particles to be dispersed is smaller than the thickness of the resin layer, the fine particles may be buried in the resin layer depending on the dispersion state of the fine particles in the resin layer, and the desired unevenness on the surface. May not be obtained. On the other hand, depending on the particle size distribution of the fine particles dispersed in the resin layer, among the fine particles dispersed in the resin, particles having a particle size larger than the thickness of the resin layer have a thin resin film on the surface. A part of the surface protrudes from the surface of the resin layer, and as a result, the surface of the resin layer, that is, the outermost surface of the developing roller, can be provided with unevenness that is preferable for carrying the toner. In addition, even if the particle size is larger than the thickness of the resin layer, the surface of the particle is covered with the resin even if it is a thin film as long as it is sufficiently dispersed in the resin. The fine particles do not fall off the surface of the resin layer due to the sliding force received during use as a developing roller. Here, when the maximum particle size of the fine particles dispersed in the resin layer is a and the thickness of the resin layer is b, the developing roller of the present invention requires that the ratio a / b be between 1.0 and 5.0. The a / b is preferably in the range of 1.0 to 3.0 from the viewpoint of forming irregularities capable of further improving toner carrying properties on the outermost surface of the developing roller. If a / b is less than 1.0, even if the fine particles have the maximum diameter, the fine particles may be buried in the resin layer depending on the dispersion state in the resin layer, and the desired surface irregularities may not be formed. On the other hand, when a / b exceeds 5.0, the unevenness on the surface of the resin layer becomes too large, and the toner carrying property is improved and the toner transport amount is increased, but the toner charge amount is insufficient, and as a result, the image is ground. Problems such as fogging and poor gradation occur.

  Further, in the developing roller 1 of the present invention, since the resin layer 4 is formed by ultraviolet irradiation or electron beam irradiation, it is not necessary to dry the resin layer 4 for a long time, and it is necessary to prepare a long drying line for mass production. No. Here, when the resin layer 4 is formed by electron beam irradiation, it is unnecessary to use a carcinogenic photopolymerization initiator because the electron beam has energy tens of thousands of times that of ultraviolet rays and is highly efficient. Further, there is an advantage that even when conductive carbon such as carbon black that easily absorbs ultraviolet rays is used for the resin layer, there is no problem in forming the resin layer.

  Furthermore, in the developing roller 1 of the present invention, since the resin layer 4 contains fluorine and the surface energy of the resin layer 4 is small, the surface friction resistance is low, it is difficult to wear even after long-term use, and it has excellent durability. .

  The shaft 2 of the developing roller of the present invention is not particularly limited as long as it has good electrical conductivity. For example, a metal core made of a metal such as iron, stainless steel, or aluminum, or a hollow interior is hollowed out. A metal shaft such as a metal cylinder can be used.

  The elastic layer 3 of the developing roller of the present invention contains an elastomer and a conductive agent, and if necessary, contains other components such as a filler. Examples of the elastomer used for the elastic layer 3 include silicone rubber, ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene rubber (NBR), natural rubber, styrene-butadiene rubber (SBR), butyl rubber, chloroprene rubber, acrylic rubber, epi rubber, Examples include chlorohydrin rubber (ECO), ethylene-vinyl acetate copolymer (EVA), polyurethane, and mixtures thereof. Among these, silicone rubber, EPDM, ECO, and polyurethane are preferable. In the elastic layer 3, the elastomer may be used as a foam by chemically foaming the elastomer using a foaming agent, or mechanically entraining and foaming air like a polyurethane foam. .

  The shaft 2 and the elastic layer 3 may be integrated using a reaction injection molding method (RIM molding method). That is, it is possible to integrate the shaft 2 and the elastic layer 3 by mixing and injecting two kinds of monomer components constituting the raw material component of the elastic layer 3 into a cylindrical mold and performing a polymerization reaction. As a result, the time required from injection of raw materials to demolding can be shortened, and production costs can be greatly reduced.

  Examples of the conductive agent used for the elastic layer 3 include an electronic conductive agent and an ionic conductive agent. Electronic conductive agents include conductive carbon such as ketjen black and acetylene black, carbon black for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT and MT, and carbon black for color subjected to oxidation treatment. , Pyrolytic carbon black, natural graphite, artificial graphite, antimony-doped tin oxide, ITO, tin oxide, titanium oxide, zinc oxide and other metal oxides, nickel, copper, silver, germanium and other metals, polyaniline, polypyrrole, polyacetylene, etc. And conductive whiskers such as carbon whisker, graphite whisker, titanium carbide whisker, conductive potassium titanate whisker, conductive barium titanate whisker, conductive titanium oxide whisker, and conductive zinc oxide whisker. The blending amount of the electronic conductive agent is preferably in the range of 1-50 parts by weight, more preferably in the range of 5-40 parts by weight with respect to 100 parts by weight of the elastomer.

  Examples of the ionic conductive agent include tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium, hexadecyltrimethylammonium, benzyltrimethylammonium, modified fatty acid dimethylethylammonium, perchlorate, chlorate, hydrochloride, bromate, and the like. Ammonium salts such as salts, iodates, borofluorides, sulfates, ethyl sulfates, carboxylates, sulfonates; alkaline metals such as lithium, sodium, potassium, calcium, magnesium, alkaline earth metals Examples include perchlorate, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, trifluoromethyl sulfate, and sulfonate. The compounding amount of the ionic conductive agent is preferably in the range of 0.01 to 10 parts by mass, more preferably in the range of 0.05 to 5 parts by mass with respect to 100 parts by mass of the elastomer. The said electrically conductive agent may be used individually by 1 type, may be used in combination of 2 or more type, and may combine an electronic conductive agent and an ionic conductive agent.

The elastic layer 3 preferably has a resistance value of 10 ³ to 10 ¹⁰ Ωcm, more preferably 10 ⁴ to 10 ⁸ Ωcm, depending on the blending of the conductive agent. If the resistance value of the elastic layer 3 is less than 10 ³ Ωcm, electric charges may leak to the photosensitive drum or the developing roller itself may be damaged by voltage, and if it exceeds 10 ¹⁰ Ωcm, ground fog is likely to occur.

  The elastic layer 3 may contain a crosslinking agent such as an organic peroxide and a vulcanizing agent such as sulfur in order to make the elastomer into a rubbery material as necessary. Sulfur accelerators, vulcanization accelerators, vulcanization retarders, and the like may be included. The elastic layer 3 is further used for rubber such as a filler, a peptizer, a foaming agent, a plasticizer, a softener, a tackifier, an anti-tacking agent, a separating agent, a release agent, an extender, and a coloring agent. You may contain a compounding agent.

  When the elastic layer 3 is formed using polyurethane or EPDM as a base material, various charge control agents such as nigrosine, triaminophenylmethane, and cationic dye, silicone resin, silicone rubber, Fine powders such as nylon may be added. Here, the addition amount of the charge control agent is preferably in the range of 1 to 5 parts by mass with respect to 100 parts by mass of the polyurethane or EPDM, and the addition amount of the fine powder is relative to 100 parts by mass of the polyurethane or EPDM. A range of 1 to 10 parts by mass is preferred.

  The hardness of the elastic layer 3 is not particularly limited, but is preferably 80 degrees or less in terms of Asker C hardness, and more preferably 30 to 70 degrees. If the Asker C hardness of the elastic layer 3 exceeds 80 degrees, the contact area between the developing roller and the photosensitive drum becomes small, and there is a possibility that good development cannot be performed, and the toner is damaged and the photosensitive drum or the stratified blade is damaged. The toner sticks and the like occurs and image defects are likely to occur. On the other hand, if the elastic layer 3 is too low in hardness, the frictional force with the photosensitive drum or the stratified blade increases, and image defects such as jitter may occur. Since the elastic layer 3 is used in contact with a photosensitive drum, a stratified blade, etc., even when the hardness is set to a low hardness, it is preferable to make the compression set as small as possible, specifically 20%. The following is preferable.

  In the developing roller of the present invention, as shown in FIG. 1, a resin layer 4 cured by ultraviolet irradiation or electron beam irradiation is formed on the elastic layer 3 in order to adjust resistance and control toner charge amount and conveyance amount. To do. In addition, fluorine is included in the resin layer 4 in order to reduce the surface energy of the resin layer 4 to reduce the frictional resistance on the surface of the resin layer 4 and improve the durability of the developing roller. Here, the resin layer 4 preferably contains 0.05 to 80% by mass of fluorine, more preferably 0.08 to 80% by mass, and still more preferably 0.1 to 80% by mass.

  The raw material composition for forming the resin layer 4 containing fluorine preferably contains a fluorine-containing compound having a polymerizable carbon-carbon double bond, and has the polymerizable carbon-carbon double bond. It may consist of only a fluorine-containing compound, and may be a mixture of a fluorine-containing compound having a polymerizable carbon-carbon double bond and another polymerizable compound having a carbon-carbon double bond. Here, as the fluorine-containing compound having a polymerizable double bond between carbon atoms, fluoroolefins and fluoro (meth) acrylates are preferable. The fluorine-containing compound having a polymerizable double bond between carbon atoms may be a monomer or an oligomer, and may be a mixture of a monomer and an oligomer. The oligomer is preferably a 2-20 mer.

The fluoroolefins are preferably olefins having 2 to 12 carbon atoms in which one or more hydrogen atoms are substituted with fluorine. Specifically, hexafluoropropene [CF ₃ CF═CF ₂ , fluorine content 76 Mass%], (perfluorobutyl) ethylene [CF ₃ (CF ₂ ) ₃ CH═CH ₂ , fluorine content 69 mass%], (perfluorohexyl) ethylene [CF ₃ (CF ₂ ) ₅ CH═CH ₂ , Fluorine content 71% by mass], (perfluorooctyl) ethylene [CF ₃ (CF ₂ ) ₇ CH═CH ₂ , fluorine content 72% by mass], (perfluorodecyl) ethylene [CF ₃ (CF ₂ ) ₉ CH = CH ₂ , fluorine content 73 mass%], chlorotrifluoroethylene [CF ₂ = CFCl, fluorine content 49 mass%], 1-methoxy- (perfluoro-2-methyl-1-propene) [(CF ₃ ) ₂ C = CFOCH ₃ Fluorine content 63 wt%, 1,4-vinyl octafluorobutane _{[CH 2 = CH- (CF 2} ) 4 -CH = CH 2, fluorine content 60 wt%, 1,6-vinyl dodecafluoro hexane [ CH ₂ ═CH— (CF ₂ ) ₆ —CH═CH ₂ , fluorine content 64 mass%], 1,8-divinylhexadecafluorooctane [CH ₂ ═CH— (CF ₂ ) ₈ —CH═CH ₂ , Fluorine content 67 mass%] and the like.

The fluoro (meth) acrylates are preferably alkyl (meth) acrylates having 5 to 16 carbon atoms in which one or more hydrogen atoms are substituted with fluorine. Specifically, 2,2,2-tri Fluoroethyl acrylate [CF ₃ CH ₂ OCOCH═CH ₂ , fluorine content 37% by mass] 2,2,3,3,3-pentafluoropropyl acrylate [CF ₃ CF ₂ CH ₂ OCOCH═CH ₂ , fluorine content 47 mass%], 2- (perfluorobutyl) ethyl acrylate [CF ₃ (CF ₂ ) ₃ CH ₂ CH ₂ OCOCH═CH ₂ , fluorine content 54 mass%], 3- (perfluorobutyl) -2-hydroxy acrylate _{[CF 3 (CF 2) 3} CH 2 CH (OH) CH 2 OCOCH = CH 2, fluorine content 49 wt%], 2- (perfluorohexyl) ethyl acrylate [CF ₃ (CF _{2) 5 H 2 CH 2 OCOCH = CH 2} , fluorine content 59 wt%], 3- (perfluorohexyl) -2-hydroxypropyl acrylate _{[CF 3 (CF 2) 5} CH 2 CH (OH) CH 2 OCOCH = CH 2 , Fluorine content 55% by mass], 2- (perfluorooctyl) ethyl acrylate [CF ₃ (CF ₂ ) ₇ CH ₂ CH ₂ OCOCH═CH ₂ , fluorine content 62% by mass], 3- (perfluorooctyl) -2-hydroxypropyl acrylate [CF ₃ (CF ₂ ) ₇ CH ₂ CH (OH) CH ₂ OCOCH═CH ₂ , fluorine content 59 mass%], 2- (perfluorodecyl) ethyl acrylate [CF ₃ (CF ₂ ) ₉ CH ₂ CH ₂ OCOCH═CH ₂ , fluorine content 65 mass%], 2- (perfluoro-3-methylbutyl) ethyl acrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₂ CH ₂ CH ₂ OCOCH═CH ₂ , Fluorine content 57 mass%], 3- (perfluoro-3-methylbutyl) -2-hydroxypropyl acrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₂ CH ₂ CH (OH) CH ₂ OCOCH = CH ₂ , fluorine Content 52 mass%], 2- (perfluoro-5-methylhexyl) ethyl acrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₄ CH ₂ CH ₂ OCOCH = CH ₂ , fluorine content 61 mass%], 3 -(Perfluoro-5-methylhexyl) -2-hydroxypropyl acrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₄ CH ₂ CH (OH) CH ₂ OCOCH = CH ₂ , fluorine content 57 mass%], 2 -(Perfluoro-7-methyloctyl) ethyl acrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₆ CH ₂ CH ₂ OCOCH═CH ₂ , fluorine content 64 mass], 3- (perfluoro-7-methyloctyl ) -2-Hydroxypropyl acrylate [(C _{3) 2 CF (CF 2)} 6 CH 2 CH (OH) CH 2 OCOCH = CH 2, fluorine content 60 wt%], 1H, 1H, 3H- tetrafluoropropyl acrylate _{[CHF 2 CF 2 CH 2 OCOCH} = CH ₂ , fluorine content 41% by mass], 1H, 1H, 5H-octafluoropentyl acrylate [CHF ₂ (CF ₂ ) ₃ CH ₂ OCOCH = CH ₂ , fluorine content 53% by mass], 1H, 1H, 7H-dodeca Fluoroheptyl acrylate [CHF ₂ (CF ₂ ) ₅ CH ₂ OCOCH═CH ₂ , fluorine content 59 mass%], 1H, 1H, 9H-hexadecafluorononyl acrylate [CHF ₂ (CF ₂ ) ₇ CH ₂ OCOCH═CH _2, the fluorine content of 63 wt%], IH-1-(trifluoromethyl) trifluoroethyl acrylate _{[(CF 3) 2 CHOCOCH =} CH 2, fluorine content 51 wt%, 1 , IH, 3H-hexafluorobutyl acrylate _{[CF 3 CHFCF 2 CH 2 OCOCH} = CH 2, fluorine content 48 wt%, 2,2,2-trifluoroethyl methacrylate _{[CF 3 CH 2 OCOC (CH} 3) = CH ₂ , fluorine content 34% by mass], 2,2,3,3,3-pentafluoropropyl methacrylate [CF ₃ CF ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 44% by mass], 2 -(Perfluorobutyl) ethyl methacrylate [CF ₃ (CF ₂ ) ₃ CH ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 51% by mass], 3- (perfluorobutyl) -2-hydroxypropyl methacrylate [CF ₃ (CF ₂ ) ₃ CH ₂ CH (OH) CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 47 mass%], 2- (perfluorohexyl) ethyl methacrylate [CF ₃ (CF ₂ ) ₅ CH _{2 H 2 OCOC (CH 3) =} CH 2, fluorine content 57 wt%], 3- (perfluorohexyl) -2-hydroxypropyl methacrylate _{[CF 3 (CF 2) 5} CH 2 CH (OH) CH 2 OCOC ( CH ₃ ) = CH ₂ , fluorine content 53 mass%], 2- (perfluorooctyl) ethyl methacrylate [CF ₃ (CF ₂ ) ₇ CH ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 61 mass %], 3-perfluorooctyl-2-hydroxypropyl methacrylate [CF ₃ (CF ₂ ) ₇ CH ₂ CH (OH) CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 57 mass%], 2- ( Perfluorodecyl) ethyl methacrylate [CF ₃ (CF ₂ ) ₉ CH ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 63 mass%], 2- (perfluoro-3-methylbutyl) ethyl methacrylate [(CF _{3) 2 CF (CF 2)} 2 C _{2 CH 2 OCOC (CH 3)} = CH 2, fluorine content 55 wt%], 3- (perfluoro-3-methylbutyl) -2-hydroxypropyl methacrylate _{[(CF 3) 2 CF (} CF 2) 2 CH 2 CH (OH) CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 51 mass%], 2- (perfluoro-5-methylhexyl) ethyl methacrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₄ CH ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 59 mass%], 3- (perfluoro-5-methylhexyl) -2-hydroxypropyl methacrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₄ CH ₂ CH (OH) CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 56 mass%], 2- (perfluoro-7-methyloctyl) ethyl methacrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₆ CH ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 62 mass%], 3- (par Fluoro-7-methyloctyl) -2-hydroxypropyl methacrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₆ CH ₂ CH (OH) CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 59 mass%], 1H, 1H, 3H-tetrafluoropropyl methacrylate [CHF ₂ CF ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 51 mass%], 1H, 1H, 5H-octafluoropentyl methacrylate [CHF ₂ (CF ₂ ) ₃ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 51 mass%], 1H, 1H, 7H-dodecafluoroheptyl methacrylate [CHF ₂ (CF ₂ ) ₅ CH ₂ OCOC (CH ₃ ) = CH ₂ , Fluorine content 57 mass%], 1H, 1H, 9H-hexadecafluorononyl methacrylate [CHF ₂ (CF ₂ ) ₇ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 61 mass%], 1H-1- (Trifle Oromethyl) trifluoroethyl methacrylate [(CF ₃ ) ₂ CHOCOC (CH ₃ ) = CH ₂ , fluorine content 48 mass%], 1H, 1H, 3H-hexafluorobutyl methacrylate [CF ₃ CHFCF ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 46 mass%] and the like.

  The other compound having a polymerizable double bond between carbon atoms that can be used in combination with the fluorine-containing compound having a polymerizable double bond between carbon atoms is not particularly limited, (Meth) acrylate monomers and oligomers, and mixtures of the monomers and oligomers are preferred. Here, as the (meth) acrylate monomer and oligomer, urethane (meth) acrylate, epoxy (meth) acrylate, ether (meth) acrylate, ester (meth) acrylate, polycarbonate (meth) acrylate, silicone Monomers and oligomers such as (meth) acrylates may be mentioned. The (meth) acrylate oligomer includes polyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol, bisphenol A type epoxy resin, phenol novolac type epoxy resin, adduct of polyhydric alcohol and ε-caprolactone, and the like (meth) It can be synthesized by reaction with acrylic acid or by urethanizing a polyisocyanate compound and a (meth) acrylate compound having a hydroxyl group.

  The urethane-based (meth) acrylate oligomer can be obtained by urethanization of a polyol, an isocyanate compound and a (meth) acrylate compound having a hydroxyl group. The epoxy-based (meth) acrylate oligomer is preferably a reaction product of a compound having a glycidyl group and (meth) acrylic acid, such as benzene ring, naphthalene ring, spiro ring, dicyclopentadiene, tricyclodecane, etc. A reaction product of a compound having a cyclic structure and a glycidyl group and (meth) acrylic acid is more preferable. Furthermore, the ether-based (meth) acrylate oligomer, the ester-based (meth) acrylate oligomer, and the polycarbonate-based (meth) acrylate oligomer are each composed of a polyol (polyether polyol, polyester polyol, and polycarbonate polyol) and (meth) acrylic acid. Obtained by reaction.

  You may mix | blend the reactive diluent which has a polymerizable double bond with the raw material composition for forming the said resin layer 4 containing a fluorine for viscosity adjustment as needed. As the reactive diluent, a monofunctional, bifunctional or polyfunctional polymerizable compound having a structure in which (meth) acrylic acid is bonded to a compound containing an amino acid or a hydroxyl group by an esterification reaction or an amidation reaction is used. be able to. The amount of the reactive diluent is preferably in the range of 10 to 200 parts by mass with respect to 100 parts by mass of the compound having a polymerizable double bond between carbon atoms in the raw material composition for forming the resin layer.

  In the present invention, fine particles 5 are dispersed in the resin layer 4 to form minute irregularities on the surface of the resin layer 4. The fine particles are preferably rubber or synthetic resin fine particles or carbon fine particles, specifically silicone rubber, silicone resin, fluororesin, urethane elastomer, urethane acrylate, melamine resin, phenol resin, (meth) acrylic resin. One or two or more of styrene resin and glassy carbon are suitable. The addition amount of the fine particles is preferably in the range of 0.1 to 100 parts by mass, more preferably in the range of 5 to 80 parts by mass with respect to 100 parts by mass of the resin.

  The average particle size of the fine particles is preferably in the range of 1 to 30 μm, and more preferably in the range of 3 to 20 μm. The ratio a / b between the maximum particle size a (μm) of the fine particles and the thickness b (μm) of the resin layer is 1.0 to 5.0, preferably 1.0 to 3.0. Here, the thickness b of the resin layer is preferably 1 to 40 μm as described later. By setting the a / b ratio within this range, appropriate fine irregularities can be formed on the surface of the resin layer.

  The resin layer 4 can be blended with a conductive agent for the purpose of controlling its conductivity, and examples of the conductive agent are the same as those exemplified as the conductive agent used for the elastic layer 3. be able to. The blending amount of the conductive agent in the resin layer 4 is preferably 20 parts by mass or less, more preferably in the range of 0.01 to 20 parts by mass, and still more preferably in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the resin. In addition, when the conductive agent is a transparent conductive agent such as a metal oxide such as nickel, copper, and tin oxide, titanium oxide, zinc oxide, potassium titanate, barium titanate, etc., ultraviolet rays are easily transmitted, The effect that the formation of the resin layer by ultraviolet irradiation is not hindered is obtained. The blending amount of the transparent conductive agent is preferably 100 parts by mass or less, more preferably in the range of 1 to 80 parts by mass, and still more preferably in the range of 10 to 50 parts by mass with respect to 100 parts by mass of the resin.

  When the resin layer 4 is formed by ultraviolet irradiation, the raw material composition for forming the resin layer preferably further contains a photopolymerization initiator. As the photopolymerization initiator, known ones can be used. For example, 4-dimethylaminobenzoic acid, 4-dimethylaminobenzoic acid ester, 2,2-dimethoxy-2-phenylacetophenone, acetophenone diethyl ketal, Benzophenone derivatives such as alkoxyacetophenone, benzyldimethyl ketal, benzophenone and 3,3-dimethyl-4-methoxybenzophenone, 4,4-dimethoxybenzophenone, 4,4-diaminobenzophenone, alkyl benzoylbenzoate, bis (4-dialkylaminophenyl) ) Ketones, benzyl derivatives such as benzyl and benzylmethyl ketal, benzoin derivatives such as benzoin and benzoin isobutyl ether, benzoin isopropyl ether, 2-hydroxy-2-methylpropiophenone, 1-hydroxy Chlohexyl phenyl ketone, xanthone, thioxanthone and thioxanthone derivatives, fluorene, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis (2 , 4,6-Trimethylbenzoyl) -phenylphosphine oxide, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1,2-benzyl-2-dimethylamino-1- (morpholinophenyl) -Butanone-1 and the like. These photoinitiators may be used individually by 1 type, and may use 2 or more types together. The blending amount of the photopolymerization initiator is preferably in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the compound having a polymerizable double bond between carbon atoms in the resin layer forming raw material composition.

  When the raw material composition for forming a resin layer contains a photopolymerization initiator, a tertiary amine photopolymerization accelerator such as triethylamine or triethanolamine, triphenyl is used to accelerate the polymerization reaction by the photopolymerization initiator. A phosphine photopolymerization accelerator such as phosphine, a thioether photopolymerization accelerator such as thiodiglycol, and the like may be further added to the resin layer forming raw material composition. The addition amount of these photopolymerization accelerators is preferably in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass of the compound having a polymerizable double bond between carbon atoms in the resin layer forming raw material composition.

  In addition, an appropriate amount of various additives can be added to the resin layer 4 as necessary.

  As a method of forming the resin layer 4 on the elastic layer 3, a coating liquid made of a composition containing the resin layer forming component and an additive is applied to the surface of the elastic layer 3, and ultraviolet rays or electrons are applied. A method of irradiating a line is preferably employed. In addition, although it is preferable that this coating liquid does not contain a solvent, you may contain the solvent which is easy to volatilize at normal temperature as a solvent. As a method for applying the coating solution, a spray method, a roll coater method, a dipping method, or the like can be used.

  In the developing roller of the present invention, it is preferable that the resin layer 4 is heated after ultraviolet irradiation or electron beam irradiation to cure the remaining unreacted compound. In this case, even if an unreacted resin layer forming compound remains in the resin layer 4 after irradiation with ultraviolet rays or an electron beam, the unreacted resin layer forming compound is cured by heating. It is possible to prevent the unreacted compound for forming the resin layer from remaining on the surface. For this reason, contamination of the photoconductor is prevented and a good image can be formed. In addition, since the thermosetting process after irradiation of an ultraviolet-ray or an electron beam only needs a very short time, the elastic layer 3 is not damaged. Here, the heating time after irradiation with ultraviolet rays or an electron beam is preferably about 5 to 120 minutes, more preferably about 10 to 40 minutes, and the heating temperature is preferably about 40 to 100 ° C, and about 50 to 80 ° C. Is more preferable. If the heating time and the heating temperature are within this range, the elastic layer 3 is not damaged by heating.

  In the developing roller of the present invention, it is also preferable that the resin layer 4 is formed by curing the remaining unreacted compound by microwave heating after ultraviolet irradiation or electron beam irradiation. In this case, even if the unreacted resin layer forming compound remains in the resin layer 4 after irradiation with ultraviolet rays or electron beams, the unreacted resin layer forming compound is cured by microwave heating, so that the resin layer It is possible to prevent the unreacted resin layer forming compound from remaining in 4. For this reason, contamination of the photoconductor is prevented and a good image can be formed. Moreover, if it is microwave heating, it is 1 type of induction heating, and it is excellent also in heating efficiency also in the point which can heat the resin layer 4 uniformly, and also it is very short, for example, 20 seconds-10 minutes. Since the remaining unreacted compound for forming the resin layer can be cured over time, the productivity is not impaired and the elastic layer 3 is not damaged. Here, the microwave heat treatment after irradiation with ultraviolet rays or electron beams is preferably performed for about 20 seconds to 30 minutes, preferably about 1 to 30 minutes, using a microwave with a frequency of 300 MHz or more, preferably about 2450 MHz. More preferably, it is more preferably performed for about 2 to 10 minutes, and particularly preferably for about 2 to 5 minutes. By such microwave heat treatment, the elastic layer 3 is not damaged and is used for forming a resin layer. The remaining unreacted compound can be uniformly cured by microwave heating.

  The thickness of the resin layer 4 is preferably in the range of 1 to 40 μm, more preferably in the range of 3 to 40 μm, and particularly preferably in the range of 3 to 30 μm. If the thickness of the resin layer 4 is less than 1 μm, the charging performance of the surface layer may not be sufficiently secured due to friction during durability, and if it exceeds 40 μm, the surface of the developing roller becomes hard and damages the toner, causing the photoreceptor to be damaged. In some cases, the toner adheres to the image forming body or the stratified blade, resulting in an image defect.

The developing roller of the present invention preferably has an electric resistance of 10 ³ to 10 ¹⁰ Ω, more preferably 10 ⁴ to 10 ⁸ Ω. If the resistance value of the developing roller is less than 10 ³ Ω, gradation control is extremely difficult, and bias leakage may occur if there is a defect in the image forming body such as a photoreceptor. On the other hand, if the resistance value exceeds 10 ¹⁰ Ω, for example, when developing toner on a latent image carrier such as a photoreceptor, the developing bias causes a voltage drop due to the high resistance of the toner carrier itself, which is sufficient for development. A developing bias cannot be secured, and a sufficient image density cannot be obtained. The resistance value is measured, for example, by pressing the outer peripheral surface of the developing roller against a flat plate or cylindrical counter electrode with a predetermined pressure, applying a voltage of 100 V between the shaft and the counter electrode, and obtaining from the current value at that time. be able to. In this way, by appropriately and uniformly controlling the resistance value of the developing roller, the electric field strength for moving the toner can be kept appropriate and uniform.

  As for the surface roughness of the developing roller of the present invention, the JIS 10-point average roughness (Rz) is preferably 1 to 30 μm, and more preferably 1 to 20 μm. When the JIS 10-point average roughness (Rz) of the developing roller is less than 1 μm, the toner carrying ability is lowered and the toner carrying amount becomes insufficient. When the developing roller exceeds 30 μm, the toner carrying amount tends to increase. Insufficient charge amount is generated, and background fogging and gradation failure occur in the image.

  The image forming apparatus of the present invention includes the above-described developing roller having a low surface frictional resistance, excellent durability, and moderately unevenness formed on the surface, and stably forms an excellent image. be able to. The image forming apparatus of the present invention is not particularly limited except that the developing roller is used, and can be manufactured by a known method.

  The image forming apparatus of the present invention will be described in detail below with reference to the drawings. FIG. 2 is a partial cross-sectional view of an example of the image forming apparatus of the present invention. The image forming apparatus in the illustrated example supplies a photosensitive drum 6 that holds an electrostatic latent image, a charging roller 7 that is positioned near (upward in the drawing) of the photosensitive drum 6 and charges the photosensitive drum 6, and toner 8. A toner supply roller 9, a developing roller 1 disposed between the toner supply roller 9 and the photosensitive drum 6, a stratification blade 10 provided in the vicinity (upper part in the drawing) of the developing roller 1, and a photosensitive drum 6 is provided with a transfer roller 11 located in the vicinity (downward in the drawing) 6 and a cleaning unit 12 provided adjacent to the photosensitive drum 6. The image forming apparatus of the present invention can further include a known component (not shown) that is usually used in the image layer forming apparatus.

  In the image forming apparatus of the illustrated example, after the photosensitive drum 6 is charged to a constant potential by the charging roller 7, an electrostatic latent image is formed on the photosensitive drum 6 by an exposure machine (not shown). Next, the photosensitive drum 6, the toner supply roller 9, and the developing roller 1 rotate in the direction of the arrow in the figure, so that the toner 8 on the toner supply roller 9 is sent to the photosensitive drum 6 through the developing roller 1. It is done. The toner 8 on the developing roller 1 is adjusted to a uniform thin layer by the stratifying blade 10 and rotates while the developing roller 1 and the photosensitive drum 6 are in contact with each other, so that the toner 8 is transferred from the developing roller 1 to the photosensitive drum 6. It adheres to the electrostatic latent image and the latent image becomes visible. The toner 8 attached to the latent image is transferred to a recording medium such as paper by the transfer roller 11, and the toner 8 remaining on the photosensitive drum 6 after the transfer is removed by the cleaning blade 13 of the cleaning unit 12. Here, in the image forming apparatus of the present invention, by using the developing roller having the above-described low surface frictional resistance, excellent durability, and moderately unevenness on the surface, the developing roller 1 can be used for a long time. It is possible to stably form an excellent image.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

[Example 1]
SANNICS FA952 (Sanyo Chemical Industries, Ltd. polyether polyol, OH value = 32) 100 parts by mass, ethylene glycol 4.0 parts by mass, Denka Black 2.0 parts by mass, H ₂ O (water) 0.6 parts by mass, SRX274C (Toray Dow Corning・ 1 part by mass of foam stabilizer manufactured by Silicone Co., Ltd., 1.5 parts by mass of TOYOCAT NP (amine catalyst manufactured by Tosoh Corporation) and 59 parts by mass of Sunfoam IC-716 (tolylene diisocyanate manufactured by Sanyo Chemical Industries, Ltd.) Stir to foam.

  A metal shaft with an outer diameter of 8.0 mm and a length of 240 mm is placed from one side opening of a metal cylindrical shape with an inner diameter of 16 mm and a length of 250 mm, and the surface is fluorinated. Injected from.

  Next, the mold in which the foamed polyurethane raw material was injected was cured in an oven at 80 ° C. for 20 minutes and then demolded to obtain a roller body having an elastic layer having an outer diameter of 16 mm and an elastic layer portion having a total length of 210 mm.

As shown in Table 1, on the outer peripheral surface of the roller body thus manufactured, 80 parts by mass of polyurethane acrylate and 20 parts by mass of 2,2,2-trifluoroethyl acrylate (fluorine content: 34% by mass) 10 parts by mass of silicone rubber fine particles with an average particle size of 3 μm (particle size distribution: 1 to 15 μm) as fine particles and 2.5 parts by mass of quaternary ammonium perchlorate (KS55 KS555) as ionic conductive agent After applying a urethane-based composition that is cured by ultraviolet irradiation to a thickness of 10 μm using a roll coater, while rotating the roller using a Ushio Electric Unicure UVH-0252C device, an illuminance of 400 mW and an integrated light quantity When the ultraviolet ray was irradiated at 1000 mJ / cm ² , the coating film was instantly cured to form an elastic resin layer. The obtained roller had the characteristics shown in Table 1 and was suitable for a developing roller.

[Example 2]
A developing roller was produced in the same manner as in Example 1 except that the elastic layer was a urethane elastomer, the blending ratio of polyurethane acrylate and 2,2,2-trifluoroethyl acrylate was changed, and the thickness of the resin layer was 7 μm. This roller also had the characteristics shown in Table 1 and was suitable for the developing roller.

[Example 3]
Polymethacrylic acid having an average particle size of 11 μm (particle size distribution: 3 to 25 μm) as a fine particle using fluoroolefin hexafluoropropene (fluorine content: 76 mass%) instead of 2,2,2-trifluoroethyl acrylate A developing roller was produced in the same manner as in Example 1 except that 10 parts by mass of methyl fine particles were blended and the thickness of the resin layer was 12 μm. This roller also had the characteristics shown in Table 1 and was suitable for the developing roller.

[Example 4]
In the formation of the resin layer, polyurethane acrylate is not blended, only hexafluoropropene is blended, and as the fine particles, 10 parts by mass of polymethyl methacrylate fine particles having an average particle size of 17 μm (particle size distribution of 4 to 35 μm) are blended, and the resin layer A developing roller was produced in the same manner as in Example 1 except that the thickness of the toner was 12 μm. This roller also had the characteristics shown in Table 1 and was suitable for the developing roller.

[Example 5]
A developing roller was produced in the same manner as in Example 1 except that 7 parts by mass of polystyrene fine particles having an average particle size of 11 μm (particle size distribution: 4 to 25 μm) were blended as fine particles, and the thickness of the resin layer was 18 μm. This roller also had the characteristics shown in Table 2 and was suitable for the developing roller.

[Example 6]
The blending ratio of polyurethane acrylate and 2,2,2-trifluoroethyl acrylate is changed, and 5 parts by mass of polystyrene fine particles having an average particle size of 16 μm (particle size distribution of 5 to 32 μm) are blended as fine particles, and the thickness of the resin layer is adjusted. A developing roller was produced in the same manner as in Example 1 except that the thickness was 25 μm. This roller also had the characteristics shown in Table 2 and was suitable for the developing roller.

[Example 7]
On the outer peripheral surface of the roller body produced in the same manner as in Example 1, as shown in Table 2, the average particle size as fine particles is 80 parts by mass of polyurethane acrylate and 20 parts by mass of 2,2,2-trifluoroethyl acrylate. 20 parts by mass of polystyrene fine particles having a diameter of 16 μm (particle size distribution of 5 to 32 μm) were blended, and a urethane composition blended with 20 parts by mass of carbon black as a conductive agent was applied with a roll coater so as to have a thickness of 12 μm. After that, an electron beam was irradiated for 10 seconds in a nitrogen stream with an acceleration voltage of 30 kV, a tube current of 300 μA, an irradiation distance of 10 mm, while rotating and rotating the roller in the axial direction using a Min-EB apparatus manufactured by Ushio Electric Co., Ltd. However, the coating film was completely cured, and an elastic resin layer was formed. This roller also had the characteristics shown in Table 2 and was suitable for the developing roller.

[Comparative Example 1]
A developing roller was produced in the same manner as in Example 1 except that the elastic layer was a urethane elastomer, no fine particles were added to the resin layer, and the thickness of the resin layer was 15 μm. In this case, as shown in Table 3, the toner conveyance amount was small and the image quality was low.

[Comparative Example 2]
Development was carried out in the same manner as in Example 1 except that 10 parts by mass of silicone rubber fine particles having an average particle size of 20 μm (particle size distribution: 3 to 80 μm) were added as fine particles to be added to the resin layer, and the thickness of the resin layer was changed to 15 μm. I made a roller. In this case, as shown in Table 3, although the toner conveyance amount increases, the image quality and durability are inferior to those of the examples.

[Comparative Example 3]
For the formation of the resin layer, 2,2,2-trifluoroethyl acrylate is not blended, only polyurethane acrylate is blended, 20 parts by mass of the same fine particles as in Example 6 are blended, and the thickness of the resin layer is 12 μm. Developed a developing roller in the same manner as in Example 1. In this case, as shown in Table 3, the durability of the roller was poor, and the image quality was inferior to that of the example.

[Comparative Example 4]
As fine particles to be added to the resin layer, 10 parts by mass of polymethyl methacrylate fine particles having an average particle size of 5 μm (particle size distribution: 1 to 12 μm) were blended, and the thickness of the resin layer was changed to 15 μm. The developer roller was manufactured. In this case, as shown in Table 3, the toner conveyance amount was small, and the image quality was inferior to that of the example.

It is sectional drawing of an example of the developing roller of this invention. 1 is a partial cross-sectional view of an example of an image forming apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Developing roller 2 Shaft 3 Elastic layer 4 Resin layer 5 Fine particle 6 Photosensitive drum 7 Charging roller 8 Toner 9 Toner supply roller 10 Layering blade 11 Transfer roller 12 Cleaning part 13 Cleaning blade

Claims (14)

In a developing roller comprising a shaft, an elastic layer formed on the outer periphery of the shaft, and a resin layer cured by ultraviolet irradiation or electron beam irradiation formed on the outer peripheral surface of the elastic layer,
Fine particles are dispersed and contained in the resin layer, the ratio a / b between the maximum particle diameter a of the fine particles and the thickness b of the resin layer is 1.0 to 5.0, and the resin layer contains fluorine. A developing roller.   The developing roller according to claim 1, wherein the resin layer cured by ultraviolet irradiation or electron beam irradiation is heated after ultraviolet irradiation or electron beam irradiation to cure the remaining unreacted compound.   2. The developing roller according to claim 1, wherein the resin layer cured by ultraviolet irradiation or electron beam irradiation is formed by curing the remaining unreacted compound by microwave heating after ultraviolet irradiation or electron beam irradiation. .   The developing roller according to claim 1, wherein an average particle diameter of the fine particles is 1 to 30 μm.   The developing roller according to claim 1, wherein a particle size distribution of the fine particles is in a range of 1 to 50 μm.   The developing roller according to claim 1, wherein a content of the fine particles is 0.1 to 100 parts by mass with respect to 100 parts by mass of the resin of the resin layer.   The developing roller according to claim 1, wherein a thickness b of the resin layer is 1 to 40 μm.   The developing roller according to claim 1, wherein the fine particles are fine particles of rubber or synthetic resin.   The fine particles are at least one of silicone rubber fine particles, silicone resin fine particles, fluorine resin fine particles, urethane elastomer fine particles, urethane acrylate fine particles, melamine resin fine particles, phenol resin fine particles, (meth) acrylic resin fine particles, and styrene resin fine particles. The developing roller according to claim 8.   The developing roller according to claim 1, wherein the fine particles are glassy carbon fine particles.   The developing roller according to claim 1, wherein the resin layer contains a conductive agent.   The developing roller according to claim 11, wherein the content of the conductive agent is 0.01 to 20 parts by mass with respect to 100 parts by mass of the resin of the resin layer.   The development according to claim 1, wherein the elastic layer is formed in a mold, and the resin layer is formed on the outer peripheral surface without polishing the outer peripheral surface. roller.   An image forming apparatus comprising a developing roller, wherein the developing roller is the developing roller according to claim 1.

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