JP4571441B2 - Developing roller and image forming apparatus having the same - Google Patents

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, development is performed by bringing a developing roller carrying toner into contact with a photosensitive drum holding an electrostatic latent image and attaching the toner to the latent image on the photosensitive drum. Therefore, it is necessary to form the developing roller with a conductive elastic body. Such a conductive elastic roller is also used in a toner jet method using an aperture electrode by providing a minute gap between the photosensitive drum and the developing roller to fly the toner.

  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 obtained by foaming these. It has a structure in which a semiconductive elastic layer made of is formed. Further, a resin coating layer may be further formed on the surface of the elastic layer for the purpose of controlling the charging property and adhesion to the toner and preventing the photosensitive drum from being contaminated by the elastic layer of the developing roller.

  Conventionally, the resin coating layer is formed by dipping the developing roller into a solvent-based or aqueous coating solution or spraying the coating solution onto the developing roller, followed by drying and curing with heat or hot air. In this case, since long time drying is required, a long drying line is necessary for mass production. In addition, the resin coating layer is required to have subtle electrical conductivity and surface condition depending on its use, but the quality distribution is affected by variations in temperature distribution and air volume in the drying line, which greatly affects the performance of the resin coating layer. There was a problem.

  On the other hand, as a method for forming a resin coating layer having a stable quality without requiring a long drying line, an ultraviolet curable compound is applied to the surface of the elastic layer of the developing roller, and the compound is cured to form a resin coating layer. Has been proposed (see Patent Document 1).

JP 2002-310136 A

  However, since the resin coating layer formed by applying an ultraviolet curable compound and curing the compound with ultraviolet rays contains an unreacted compound, the photosensitive drum may be contaminated. In particular, when a carbon-based electronic conductive agent is blended to adjust the electrical resistance of the resin coating layer, the carbon-based electronic conductive agent absorbs ultraviolet rays, so that the ultraviolet curable compound does not sufficiently undergo a curing reaction, There was a problem that the reaction compound easily remained. In addition, a developing roller provided with a resin coating layer formed by ultraviolet curing on the outer peripheral surface of the elastic layer has a problem that toner is easily laminated on the roller surface depending on the use conditions because the toner release property on the roller surface is low. It was. For this reason, when an image forming apparatus incorporating such a developing roller is used for a long time, there is a problem that toner filming occurs on the surface of the developing roller or the surface resistance increases, and image defects are likely to occur.

  Therefore, the object of the present invention is to solve the above-mentioned problems of the prior art, to prevent contamination of the photosensitive drum, to prevent toner filming on the surface or to increase resistance even when used for a long time, and to have excellent durability. Another object is to provide a developing roller. Another object of the present invention is to provide an image forming apparatus provided with such a developing roller and capable of 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 found that in a developing roller in which a resin coating layer is provided on the surface of the elastic layer, a non-electron beam curable fluorine-containing resin and / or Alternatively, by using the compound and the electron beam curable resin, the remaining amount of the unreacted compound can be reduced, and the toner adhesion on the roller surface is lowered. It has been found that resistance increases are unlikely to occur, and the present invention has been completed.

That is, the developing roller of the present invention includes a shaft, an elastic layer formed on the outer periphery of the shaft, and at least one resin coating layer formed on the outer peripheral surface of the elastic layer. coating layer is composed of a electron beam-curable resins cured by per molecular weight of 1,000 (meth) fluorine-containing copolymer of a non-electron beam-curable acryloyl group contains less than 0 to 0.01 polymer resin and an electron beam, the non-electronic A coating liquid containing a line-curable fluorine-containing copolymer resin and a resin and / or compound having a carbon-carbon double bond that can be polymerized by an electron beam and not containing fluorine is applied to the outer peripheral surface of the elastic layer. After coating, a resin and / or compound having a carbon-carbon double bond that can be polymerized by the electron beam by electron beam irradiation and not containing fluorine is cured, and the carbon atoms that can be polymerized by the electron beam. Double connection Does not contain and fluorine has a resin and / or compound, characterized in that it is a (meth) acrylate monomer and / or oligomer. Here, the electron beam curable resin is obtained by curing a resin and / or compound polymerizable by an electron beam by electron beam irradiation. Also, a non-electron beam-curing copolymer resin to form a resin coating layer in the present invention, a high electron-sensitive per molecular weight of 1,000 (meth) acryloyl groups is a copolymer resin containing less than 0 and 0.01, A value close to 0 is preferable. Resins and compounds that can be polymerized by an electron beam include resins and oligomers containing (meth) acryloyl groups having a high electron beam sensitivity of 0.01 or more, preferably 0.1 or more per 1,000 molecular weight, and one or more in one molecule. It is a (meth) acrylate having a (meth) acryloyl group.

In a preferred example of the developing roller of the present invention, the non-electron beam curable fluorine-containing copolymer resin is a fluorine-containing (meth) acrylate copolymer resin , a fluorine-containing olefin copolymer resin , or a fluorine-containing ether. Copolymer resin , fluorine-containing ester copolymer resin , fluorine-containing epoxy copolymer resin , and fluorine-containing urethane copolymer resin .

In the developing roller of the present invention, the electron beam curing resin, an electron beam-curable resin containing no fluorine.

  In another preferred embodiment of the developing roller of the present invention, the resin coating layer contains a carbon-based electronic conductive agent. Since the electron beam is difficult to be absorbed by the carbon-based electron conductive agent, the remaining amount of the unreacted compound can be sufficiently suppressed even if the carbon-based electron conductive agent is used for adjusting the electric resistance of the resin coating layer.

  In another preferred embodiment of the developing roller of the present invention, the resin coating layer has a thickness of 1 to 500 μm. Since the electron beam reaches the deep part of the resin coating layer, the remaining amount of the unreacted compound can be sufficiently suppressed even if the resin coating layer is thick.

  The image forming apparatus of the present invention includes at least a developing roller, and the developing roller is the developing roller.

  According to the present invention, in the developing roller having a resin coating layer disposed on the surface of the elastic layer, a non-electron beam curable fluorine-containing resin and / or compound and an electron beam curable resin are used for the resin coating layer. Therefore, it is possible to provide a developing roller that does not contaminate the photosensitive drum, has little toner adhesion on the roller surface, hardly undergoes toner filming and resistance increase even when used for a long period of time, and has excellent durability. Further, it is possible to provide an image forming apparatus including such a developing roller and capable of forming 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 coating layer 4 formed on the outer peripheral surface of the elastic layer 3. In the drawing, the resin coating layer 4 is composed of one layer, but the resin coating layer 4 of the developing roller of the present invention may be composed of two or more layers.

  In the developing roller 1 of the present invention, since the resin coating layer 4 is formed by electron beam irradiation, it is possible to prevent residual unreacted compounds by optimizing the electron beam irradiation amount. Moreover, the crosslinking density of the resin coating layer 4 can also be adjusted by controlling the acceleration voltage of an electron beam. Furthermore, since the electron beam is difficult to be absorbed by the carbon-based electron conductive agent, even when a carbon-based electron conductive agent is used for the resin coating layer 4, an electron beam curable resin can be sufficiently generated by electron beam irradiation, Unreacted compounds can be prevented from remaining.

Further, in the developing roller 1 of the present invention, the resin coating layer 4 is made of a non-electron beam-curing the fluorine-containing copolymer resin and electron beam-curable resin, the surface of the non-electron beam-curable fluorine-containing copolymer resin Since the energy is small, toner adhesion on the surface is small, toner filming and resistance increase hardly occur even when used for a long period of time, and excellent durability. In general, the fluorine-containing resin and / or compound has poor compatibility with the elastic layer 3 and is inferior to general resin in adhesion to the elastic layer 3, but the resin coating layer 4 of the developing roller of the present invention. , The surface energy of the non-electron beam curable fluorine-containing copolymer resin is smaller than the surface energy of a normal electron beam curable resin, so that it does not contact the surface side of the resin coating layer 4 (that is, does not contact the elastic layer 3). The non-electron beam curable fluorine-containing copolymer resin tends to be unevenly distributed on the side), and as a result, the non-electron beam curable fluorine-containing copolymer resin on the side in contact with the elastic layer 3 of the resin coating layer 4 is contained. A rate falls and the adhesiveness of the resin coating layer 4 and the elastic layer 3 improves. Further, as a result of the non-electron beam curable fluorine-containing copolymer resin being unevenly distributed on the surface side of the resin coating layer 4, the releasability of the resin coating layer 4 from the toner is improved. Further, even if reducing the content of non-electron beam-curing the fluorine-containing copolymer resin of the resin coating layer 4, since the non-electron beam-curable fluorine-containing copolymer resin is unevenly distributed on the surface side of the resin coating layer 4 Further, the content of the expensive fluorine-containing copolymer resin can be maintained while sufficiently maintaining the releasability of the resin coating layer 4 from the toner and improving the adhesion between the resin coating layer 4 and the elastic layer 3. Can also be reduced.

  The shaft of the developing roller of the present invention is not particularly limited as long as it has good conductivity. For example, a metal core made of a solid metal such as iron, stainless steel, or aluminum, or a metal hollowed inside A metal shaft such as a cylindrical body can be used.

  The elastic layer of the developing roller of the present invention contains an elastomer and a conductive agent, and optionally contains other components such as a filler. Examples of the elastomer used for the elastic layer include silicone rubber, ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene rubber (NBR), natural rubber, styrene-butadiene rubber (SBR), butyl rubber, chloroprene rubber, acrylic rubber, and epichloro. Examples include hydrin 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, 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 and the elastic layer may be integrated using a reaction injection molding method (RIM molding method). That is, it is possible to integrate the shaft and the elastic layer by mixing and injecting two kinds of monomer components constituting the raw material component of the elastic layer 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.

  When silicone rubber is used for the elastic layer, the silicone rubber may be general millable silicone rubber (HCR) or liquid silicone rubber (LSR). In addition, when using liquid silicone rubber, it is preferable to form an elastic layer by liquid injection molding (LIM: Liquid injection Molding). The above liquid silicone rubber contains vinyl group-containing polyorganosiloxane with organohydrogenpolysiloxane, reinforcing filler such as silica, conductive agent, platinum-based catalyst, reaction inhibitor, silicone oil, and other various additives. After being injected into a mold having a predetermined shape, it is molded by heat curing.

（式中、Ｒ¹は、それぞれ独立して一価の炭化水素基であり、ｎは100〜10,000の整数である）で表される化合物が好ましい。ここで、Ｒ¹における、一価の炭化水素基としては、メチル基、エチル基、プロピル基、ブチル基及びペンチル基等のアルキル基、ビニル基及びアリル基等のアルケニル基、シクロヘキシル基等のシクロアルキル基、フェニル基等のアリール基、ベンジル基等のアラルキル基等が挙げられる。 The vinyl group-containing polyorganosiloxane has two or more reactive groups in the molecule, and examples of the reactive group include an alkenyl group and a hydroxyl group. As the vinyl group-containing polyorganosiloxane, the following formula (I):

In the formula, R ¹ is each independently a monovalent hydrocarbon group, and n is an integer of 100 to 10,000. Here, the monovalent hydrocarbon group in R ¹ includes an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group and a pentyl group, an alkenyl group such as a vinyl group and an allyl group, and a cyclohexyl group such as a cyclohexyl group. Examples include alkyl groups, aryl groups such as phenyl groups, and aralkyl groups such as benzyl groups.

（式中、Ｒ²は、それぞれ独立して水素又は一価の炭化水素基であり、ｍは10〜1,000の整数である）で表され、分子中に２個以上のケイ素−水素結合を有する化合物が好ましい。ここで、Ｒ²における、一価の炭化水素基としては、メチル基、エチル基、プロピル基、ブチル基及びペンチル基等のアルキル基、ビニル基及びアリル基等のアルケニル基、シクロヘキシル基等のシクロアルキル基、フェニル基等のアリール基、ベンジル基等のアラルキル基等が挙げられる。 Examples of the organohydrogenpolysiloxane include the following formula (II):

(Wherein R ² is each independently hydrogen or a monovalent hydrocarbon group, m is an integer of 10 to 1,000), and has two or more silicon-hydrogen bonds in the molecule. Compounds are preferred. Here, the monovalent hydrocarbon group in R ² includes alkyl groups such as methyl group, ethyl group, propyl group, butyl group and pentyl group, alkenyl groups such as vinyl group and allyl group, and cyclohexane such as cyclohexyl group. Examples include alkyl groups, aryl groups such as phenyl groups, and aralkyl groups such as benzyl groups.

  In addition, as a conductive agent contained in the liquid silicone rubber, a conductive agent generally used for an elastic layer to be described later can be used. As a platinum-based catalyst, platinous chloride, chloroplatinic acid, alcohol-modified chloroplatinic acid can be used. Examples of the reaction inhibitor include methylvinylcyclotetrasiloxane, acetylene alcohols, siloxane-modified acetylene alcohol, hydroperoxide and the like.

  Examples of the conductive agent used for the elastic layer 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. Conductive whiskers such as conductive polymer, 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 to 50 parts by mass, more preferably in the range of 5 to 40 parts by mass with respect to 100 parts by mass 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 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 is less than 10 ³ Ωcm, the charge may leak to the photosensitive drum or the like, and the developing roller itself may be damaged by the voltage. If the resistance value exceeds 10 ¹⁰ Ωcm, fogging tends to occur.

  The elastic layer 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, if necessary. Accelerators, vulcanization accelerators, vulcanization retarders, and the like may be included. In addition, the elastic layer further comprises a rubber compounding agent 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, a bulking agent, and a coloring agent. An agent may be contained.

  When forming the elastic layer using polyurethane or EPDM as a base material, various charge control agents such as nigrosine, triaminophenylmethane, and cationic dyes, silicone resin, silicone rubber, nylon are used to control the toner charge amount on the surface. A fine powder such as 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 is not particularly limited, but is preferably 80 degrees or less in terms of Asker C hardness, and more preferably 20 to 70 degrees. When the Asker C hardness of the elastic layer exceeds 80 degrees, the contact area between the developing roller and the photosensitive drum becomes small, and there is a risk that good development cannot be performed. Toner sticking or the like occurs and image defects are likely to occur. On the other hand, if the elastic layer is too low in hardness, the frictional force with the photosensitive drum or the stratified blade increases, which may cause image defects such as jitter. Since the elastic layer is used in contact with a photosensitive drum, a stratified blade or the like, even when the hardness is set to a low hardness, it is preferable to make the compression set as small as possible, specifically 20% or less. It is preferable.

  The surface roughness of the elastic layer is not particularly limited, but the JIS 10-point average roughness (Rz) is preferably 30 μm or less, and more preferably 1 to 20 μm. When the surface roughness (Rz) of the elastic layer exceeds 30 μm, the layer thickness of the toner layer and the uniformity of charging may be impaired. By setting the surface roughness to 30 μm or less, toner adhesion can be improved. In addition, it is possible to more reliably prevent image deterioration due to roller wear during long-term use. In order to obtain an appropriate surface roughness, the roller surface may be polished. However, if a polishing step is provided, the productivity of the roller is deteriorated and the manufacturing cost is increased. Therefore, it is preferable that the mold surface for molding the elastic layer is appropriately roughened, and the rough surface of the mold surface is transferred to the surface of the elastic layer to be molded to obtain the above surface roughness.

Resin coating layer of the developing roller of the present invention is formed of a non-electron beam-curing the fluorine-containing copolymer resin and electron beam-curable resins cured by electron beam. The resin coating layer comprises a coating liquid containing a non-electron beam curable fluorine-containing copolymer resin and a resin and / or compound having a double bond between carbon atoms that can be polymerized by an electron beam and not containing fluorine. After coating on the outer surface of the elastic layer, the resin and / or compound having a carbon-carbon double bond polymerizable by the electron beam and not containing fluorine are cured by electron beam irradiation. In general, by providing a resin coating layer on the outer surface of the elastic layer, the resistance value can be adjusted, the toner charge amount and the toner conveyance amount can be controlled, and the frictional force between the developing roller and the stratified blade can be controlled. but by the resin coating layer is made of a non-electron beam-curing the fluorine-containing copolymer resin and electron beam-curable resin, the toner adhesion of the resin coating layer is greatly reduced, greatly durability of the developing roller Can be improved. Here, the coating liquid preferably contains a reactive diluent and a conductive agent, and may contain a known additive as required, and preferably does not contain a solvent. Examples of a method for applying the coating liquid to the surface of the elastic layer include a spray method, a roll coater method, a dipping method, and a die coating method. Moreover, the conditions of electron beam irradiation are suitably selected according to the kind and application amount of electron beam curable resin.

In the resin coating layer, the ratio of the non-electron beam curable fluorine-containing copolymer resin and the electron beam curable resin is such that the electron beam curable resin is 100 parts by mass with respect to 100 parts by mass of the non-electron beam curable fluorine-containing copolymer resin. Is preferably in the range of 10 to 10,000 parts by mass, more preferably in the range of 30 to 5000 parts by mass. When the blending amount of the electron beam curable resin with respect to 100 parts by mass of the non-electron beam curable fluorine-containing copolymer resin is less than 10 parts by mass, the degree of crosslinking due to electron beam curing may be insufficient, and the coating strength may be reduced. If it exceeds 10000 parts by mass, the fluorine content decreases and the intended performance is not exhibited.

  The fluorine content in the resin coating layer is preferably in the range of 0.1 to 45% by mass, and more preferably in the range of 0.5 to 20% by mass. When the fluorine content in the resin coating layer is less than 0.1% by mass, sufficient performance for toner adhesion may not be exhibited. When it exceeds 45% by mass, the adhesion to the elastic layer or the lower layer is lowered.

The non-electron beam curable fluorine-containing copolymer resin used for the resin coating layer is preferably one that is dispersed or dissolved in a coating solution, such as a fluorine-containing (meth) acrylate copolymer resin , a fluorine-containing olefin copolymer. Examples include coalesced resins , fluorine-containing ether-based copolymer resins , fluorine-containing ester-based copolymer resins , fluorine-containing epoxy-based copolymer resins , and fluorine-containing urethane-based copolymer resins . The non-electron beam curable fluorine-containing copolymer resin may be used alone or in combination of two or more. Here, the fluorine content of the non-electron beam curable fluorine-containing copolymer resin is preferably in the range of 2 to 80% by mass, and more preferably in the range of 2 to 70% by mass. When the fluorine content of the non-electron beam curable fluorine-containing copolymer resin is less than 2% by mass, the effect of fluorine is insufficient, and when it exceeds 80% by mass, compatibility and dispersibility are problems.

（式中、Ｘは、炭素数１〜２０のアルキレン基、パーフルオロアルキレン基又は部分フッ素化アルキレン基で、直鎖状及び分岐状のいずれでもよく、更には、これらアルキレン基、パーフルオロアルキレン基及び部分フッ素化アルキレン基中の主鎖又は側鎖中に酸素原子が介在したものであってもよく；Ｒ³は、水素、メチル基、塩素、フッ素又はシアノ基である）で表される化合物が好ましい。ここで、樹脂被覆層の耐久性を向上させる観点から、式(III)中のＸが炭素数４以上のアルキレン基、パーフルオロアルキレン基又は部分フッ素化アルキレン基であるのが好ましく、炭素数６以上のアルキレン基、パーフルオロアルキレン基又は部分フッ素化アルキレン基であるのが更に好ましく、−(ＣＨ₂)₂−(ＣＦ₂)₇−であるのが特に好ましい。 Examples of the non-electron beam curable fluorine-containing (meth) acrylate copolymer resin include perfluoroalkyl esters and partially fluorinated alkyl esters of (meth) acrylic acid, and perfluoroalkyl groups or partially fluorinated alkyl groups. organic linking group linked via a (meth) and fluorine-containing (meth) acrylates such as acrylic acid esters, (meth) methyl acrylate, ethyl, butyl, octyl, alkyl esters of dodecyl and the like; hydroxyethyl, hydroxybutyl Hydroxyalkyl esters such as glycidyl ester, and copolymers with fluorine-free (meth) acrylates. The copolymer may further be copolymerized with a small amount of polysiloxane group-containing (meth) acrylate. Here, the carbon number of the perfluoroalkyl group or the partially fluorinated alkyl group in the fluorine-containing (meth) acrylate is preferably in the range of 1-20. In addition, as the fluorine-containing (meth) acrylate, the following formula (III):

(In the formula, X is an alkylene group having 1 to 20 carbon atoms, a perfluoroalkylene group or a partially fluorinated alkylene group, which may be linear or branched, and further, these alkylene groups and perfluoroalkylene groups. And a compound in which an oxygen atom may be present in the main chain or side chain in the partially fluorinated alkylene group; R ³ is hydrogen, methyl group, chlorine, fluorine or cyano group) Is preferred. Here, from the viewpoint of improving the durability of the resin coating layer, X in the formula (III) is preferably an alkylene group having 4 or more carbon atoms, a perfluoroalkylene group or a partially fluorinated alkylene group, and having 6 carbon atoms. The above alkylene group, perfluoroalkylene group or partially fluorinated alkylene group is more preferable, and — (CH ₂ ) ₂ — (CF ₂ ) ₇ — is particularly preferable.

  The fluorine-containing (meth) acrylate-based resin may have a functional group capable of crosslinking reaction in the molecule, and examples of the functional group capable of crosslinking reaction include a hydroxyl group, a thiol group, a carboxyl group, an amino group, and an isocyanate. Group, aziridinyl group, glycidyl group, alkoxysilyl group, silanol group, cyclocarbonate group, acid anhydride group, vinyl group, enol ether group, thioether group, active ester group, acetoacetate group, metal salt, metal oxide and these Examples include functional groups blocked with various blocking agents. As the compound that reacts with the functional group capable of crosslinking reaction, a reactive polyfunctional compound having two or more reactive functional groups in the molecule can be used, and the reactive functional group includes the above-described crosslinking reaction. The same functional groups as possible functional groups can be mentioned. As said reactive polyfunctional compound, an organic epoxy compound and an organic polyisocyanate compound are preferable from a viewpoint of industrial usefulness.

  Examples of the organic epoxy compound include compounds having two or more glycidyl groups, and specifically include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, sorbitol polyglycidyl. Ether, polyethylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin polyglycidyl ether, diglycerin polyglycidyl ether, tri Methylolpropane polyglycidyl ether, spiroglycol diglycidyl ether, various Carboxymethyl resins.

  Specific examples of the organic polyisocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2, 4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-phenylene diisocyanate, 3,3'-dichloro -4,4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 3, , 3′-dimethyl-4,4′-dicyclohexylmethane diisocyanate and the like, dimers and trimers thereof, and isocyanate groups of these compounds are converted to phenols, oximes, alcohols, active methylenes, mercaptans, acids And polyisocyanates partially blocked with amides, imides, amines, imidazoles, ureas, carbamates, imines or sulfites.

Further, as the non-electron beam-curable fluorine-containing olefin copolymer resin, specifically, vinylidene fluoride - tetrafluoroethylene copolymer, ethylene - tetrafluoroethylene copolymer, vinylidene fluoride - tetrafluoroethylene Examples thereof include an ethylene-hexafluoropropylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, a vinylidene fluoride-hexafluoropropylene copolymer, and a fluorinated vinyl ether-tetrafluoroethylene copolymer. The fluorine-containing polyolefin copolymer resin is obtained by copolymerizing fluorine-containing olefin monomers such as vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, and vinyl fluoride ether.

  On the other hand, as the electron beam curable resin used for the resin coating layer, polyester resin, polyether resin, fluorine resin, epoxy resin, amino resin, polyamide resin, acrylic resin, acrylic urethane resin, urethane resin, alkyd resin, phenol resin Melamine resin, urea resin, silicone resin, polyvinyl butyral resin, vinyl ether resin, vinyl ester resin, and modified resins having a specific functional group introduced into these resins. You may mix and use a seed | species or more. Moreover, it is preferable to introduce a crosslinked structure into the resin coating layer in order to improve mechanical strength and environmental resistance.

The electron beam-curable resin is formed by a resin and / or compound is cured by electron beam irradiation having a double bond polymerizable carbon atoms by an electron beam. Here, the resin and / or compound having a polymerizable double bond between carbon atoms does not contain fluorine . In addition, the resin and / or compound which has a carbon-carbon double bond polymerizable by the electron beam and does not contain fluorine may be used alone or in combination of two or more. .

The inter-electron beam curing resin polymerizable carbon atoms used for forming the fluorine-free double bonds resin and / or compound is a (meth) acrylate monomer and / or oligomer. 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.

  Various additives such as a reactive diluent having a polymerizable double bond and a conductive agent may be further blended in the coating liquid used for forming the resin coating layer, if necessary. By blending a reactive diluent having a polymerizable double bond into the coating solution, the viscosity of the coating solution can be adjusted. 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 compounding amount of the reactive diluent is preferably in the range of 10 to 200 parts by mass with respect to a total of 100 parts by mass of the resin and compound polymerizable by the electron beam.

  In addition, as the conductive agent used in the coating liquid, the electronic conductive agent and the ionic conductive agent exemplified as the conductive agent for the elastic layer can be used. Since the electron beam is not easily absorbed by the carbon-based electron conductive agent, in the present invention, the carbon-based electron conductive agent can also be suitably used for the resin coating layer. Here, as the carbon-based electron conductive agent, conductive carbon such as ketjen black and acetylene black, carbon black for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT and MT, oxidation treatment, etc. And carbon black for color, pyrolytic carbon black, natural graphite, artificial graphite, carbon whisker, graphite whisker and the like. The blending amount of the electron conducting agent is preferably 100 parts by mass or less, and 1 to 80 parts by mass with respect to a total of 100 parts by mass of the non-electron beam curable fluorine-containing resin and compound and a resin and compound polymerizable by electron beam. The range of parts is further preferred, and the range of 10 to 50 parts by mass is even more preferred. On the other hand, the blending amount of the ionic conductive agent is preferably 20 parts by mass or less with respect to a total of 100 parts by mass of the non-electron beam curable fluorine-containing resin and compound and a resin and compound polymerizable by electron beam, The range of 20 parts by mass is more preferable, and the range of 1 to 10 parts by mass is even more preferable.

  The thickness of the resin coating layer is preferably in the range of 1 to 500 μm, more preferably in the range of 3 to 200 μm, and still more preferably in the range of 5 to 100 μm. If the thickness of the resin coating layer is less than 1 μm, the electrical performance of the developing roller surface may not be sufficiently ensured due to friction during long-term use. If the thickness exceeds 500 μm, the developing roller surface becomes hard and damages the toner. In some cases, the toner adheres to the photosensitive drum or the stratified blade to cause image defects.

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 difficult, and if the photosensitive drum or the like is defective, a bias leak may occur. On the other hand, if the resistance value of the developing roller is more than 10 ¹⁰ Omega, when developing the toner to the photosensitive drum or the like, the developing bias causes a voltage drop by the high resistance of the developing roller itself can be ensured sufficient developing bias to the developing As a result, 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. Note that it is important to appropriately and uniformly control the resistance value of the developing roller in order to keep the electric field strength for moving the toner properly and uniformly.

  The image forming apparatus of the present invention includes the above-described developing roller that has less surface toner adhesion and excellent durability, and can form a good image over a long period of time. 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 of the illustrated example includes a toner supply roller 6 for supplying toner 5, a photosensitive drum 7 that holds an electrostatic latent image, and the above-described toner disposed between the toner supply roller 6 and the photosensitive drum 7. The developing roller 1, the stratified blade 8 provided in the vicinity of the developing roller 1 (upper part in the figure), the charging roller 9 located in the vicinity of the photosensitive drum 7 (upper in the figure), and the vicinity of the photosensitive drum 7 (in the figure) A transfer roller 10 located on the lower side and a cleaning unit 11 provided adjacent to the photosensitive drum 7. 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 7 is charged to a constant potential by the charging roller 9, an electrostatic latent image is formed on the photosensitive drum 7 by an exposure machine (not shown). Next, the toner supply roller 6, the developing roller 1, and the photosensitive drum 7 rotate in the direction of the arrow in the drawing, so that the toner 5 on the toner supply roller 6 is sent to the photosensitive drum 7 through the developing roller 1. It is done. The toner 5 on the developing roller 1 is adjusted to a uniform thin layer by the stratifying blade 8, and the toner 5 is transferred from the developing roller 1 to the photosensitive drum 7 by rotating while the developing roller 1 and the photosensitive drum 7 are in contact with each other. It adheres to the electrostatic latent image and the latent image becomes visible. The toner 5 attached to the latent image is transferred onto a recording medium such as paper by the transfer roller 10, and the toner 5 remaining on the photosensitive drum 7 after the transfer is removed by the cleaning blade 12 of the cleaning unit 11. Here, in the image forming apparatus according to the present invention, the toner adhering to the surface of the developing roller 1 is low, toner filming or resistance does not easily occur even after long-term use, and the book has excellent durability. By using the developing roller of the invention, it is possible to form a good image over a long period of time. Further, the developing roller 1 does not contaminate the photosensitive drum 7 because the remaining of the unreacted compound in the resin coating layer 4 is sufficiently suppressed.

  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 Kasei Kogyo Co., Ltd. polyether polyol, OH value = 37] 100 parts by mass, SRX274C [Toray Dow Corning Silicone Co., Ltd. foam stabilizer] 1 part by mass, TOYOCAT NP [Tosoh Corporation amine catalyst] 2.8 parts by mass, 1.5 parts by mass of TOYOCAT EP [amine catalyst manufactured by Tosoh Corporation] and 59 parts by mass of Sunfoam IC-716 [Sanyo Chemical Co., Ltd. Tolylene Diisocyanate] were mechanically stirred and foamed.

  Next, a metal shaft with an outer diameter of 8.0 mm and a length of 240 mm is arranged from one side opening of a metal cylindrical mold having an inner diameter of 16 mm and a length of 250 mm, and the surface is fluorinated. Was injected from the foaming machine.

  Next, the mold in which the foamed polyurethane raw material was injected was heated in an oven at 80 ° C. for 20 minutes and then removed from the mold, and a roller body having an elastic layer made of urethane foam having an outer diameter of 16 mm and a total length of the foam portion of 230 mm was obtained. Produced.

  A coating liquid having the composition shown in Table 1 was applied to the outer peripheral surface of the roller body with a roll coater, and while rotating the roller using a Min-EB apparatus manufactured by Ushio Electric Co., Ltd., an acceleration voltage of 30 kV, a tube current of 300 μA, When irradiated with an electron beam under the conditions of an irradiation distance of 100 mm, a nitrogen atmosphere of 760 Torr, and an irradiation time of 1 minute, the coating solution is instantly cured to form an elastic resin coating layer, and the resin coating layer is formed on the outer peripheral surface of the roller body. Thus, a developing roller having was obtained. The toner charge amount and toner transport amount of the obtained developing roller are evaluated by a known method, and the developing roller is incorporated in the image forming apparatus, and the image density, the presence of halftone spots, the presence of fogging, and the density difference between the leading and trailing edges are measured. Evaluated by a known method, and further adhered to the toner on the developing roller surface after printing 10,000 sheets, and incorporated into the developing roller image forming apparatus, and examined image density, presence of halftone spots, presence of fogging, and difference in front and rear end density. . These results are shown in Table 1.

(Example 2)
100 parts by mass of Nipol IR2200L (manufactured by Zeon Corporation) with Mooney viscosity ML _{1 + 4} (100 ° C.) of 70, 60 parts by mass of LIR-30 (manufactured by Kuraray) with an average molecular weight of 29,000, carbon black TB # 5500 (manufactured by Tokai Carbon Co., Ltd.) 28 A rubber composition was prepared by kneading 5 parts by mass, 5 parts by mass of zinc oxide, 1 part by mass of stearic acid, and 9 parts by mass of perhexa C-40 (manufactured by NOF Corporation) using a 55 L kneader. The rubber composition was extruded into a cylindrical shape using a cross-head type extruder from Mitsuba Manufacturing Co., Ltd., to a cored bar having an outer diameter of φ8 mm to which an adhesive had been attached, to obtain an unvulcanized rubber / cored bar integral molding. This was set in a cylindrical mold, vulcanized at 175 ° C. for 20 minutes under a pressure of 3.2 × 10 ⁶ Pa. The pressure of the split mold was released to obtain a rubber roller, and further vulcanized in an oven at 180 ° C. for 4 hours. The obtained roller was plunge-type polished to a diameter of 16 mm with a rotating grindstone to obtain a rubber roller. A developing roller was produced in the same manner as in Example 1 except that the resin coating layer was formed on the outer peripheral surface of the roller body using the coating liquid having the composition shown in Table 1. Table 1 shows the physical properties and performance of the obtained developing roller.

(Example 3)
50 parts by mass of carbon black TB # 5500 (manufactured by Tokai Carbon) with respect to 100 parts by mass of EPDM having an iodine value of 36 and a Mooney viscosity ML _{1 + 4} (100 ° C.) of 39, Nobelite A (manufactured by Nippon Flour Industries) 36 parts by weight, 60 parts by weight of Diana Process Oil PW90 (made by Idemitsu Kosan), 3 parts by weight of zinc white, 2 parts by weight of stearic acid, 1 part by weight of vulcanization accelerator 2-mercaptothiazole, 1.5 parts by weight of sulfur, foaming agent Neo Cerbon N 6 parts by mass of # 1000M (manufactured by Eiwa Kasei Kogyo) were kneaded using a 55 L kneader to prepare a foamed rubber composition. The foamed rubber composition was extruded into a cylindrical shape using a cross-head type extruder from Mitsuba Manufacturing Co., Ltd. to a cored bar having an outer diameter of φ8 mm to which an adhesive had been attached, to obtain an unvulcanized rubber / cored bar integrally molded product. This was set in a cylindrical mold, vulcanized and foamed at 175 ° C. for 20 minutes under a pressure of 3.2 × 10 ⁶ Pa. The pressure of the split mold was released to obtain a foamed rubber roller with a skin layer, and further vulcanized in an oven at 180 ° C. for 4 hours. The obtained roller was plunge-type polished to a diameter of 16 mm with a rotating grindstone to obtain a foamed rubber roller. A developing roller was produced in the same manner as in Example 1 except that the resin coating layer was formed on the outer peripheral surface of the roller body using the coating liquid having the composition shown in Table 1. Table 1 shows the physical properties and performance of the obtained developing roller.

Example 4
After adding 1.6 parts by weight of conductive carbon and 0.15 parts by weight of dibutyltin dilaurate to 100 parts by weight of a trifunctional and 9,000 molecular weight polyether polyol obtained by adding propylene oxide to glycerin, sufficiently stirring and mixing, and then stirring for 20 minutes under reduced pressure This was defoamed and used as a polyol component. The hydroxyl value of the polyol component was 19 mgKOH / g. On the other hand, polypropylene glycol-modified polymeric MDI having an NCO content of 11% was degassed as an isocyanate component for 20 minutes while stirring under reduced pressure to obtain an isocyanate component. The polyol component and isocyanate component are mixed at a high speed of 3000 rpm with a two-component casting machine so that the ratio of the polyol component to the isocyanate component is 101.75 / 13.70 (isocyanate index: 103). Was poured into a cylindrical mold set with a core metal of φ8 mm, and heated and cured in a hot air circulating oven at 90 ° C. for 60 minutes. A urethane roller with a cored bar was taken out from the cylindrical mold to obtain a roller. A developing roller was produced in the same manner as in Example 1 except that the resin coating layer was formed on the outer peripheral surface of the roller body using the coating liquid having the composition shown in Table 1. Table 1 shows the physical properties and performance of the obtained developing roller.

( Reference Example 1 )
Liquid silicone LIM liquid # 2090 (made by Toray Dow Corning Silicone) is stirred and degassed, then poured into a cylindrical mold set with a core metal with an outer diameter of φ8 mm, and heated with air at 120 ° C for 30 minutes It was heated and cured in a circulation oven. A roller with a cored bar was taken out from the cylindrical mold and cured by heating in a hot air circulation oven at 200 ° C. for 4 hours to obtain a roller. A developing roller was produced in the same manner as in Example 1 except that the resin coating layer was formed on the outer peripheral surface of the roller body using the coating liquid having the composition shown in Table 1. Table 1 shows the physical properties and performance of the obtained developing roller.

( Reference Example 2 )
A developing roller was produced in the same manner as in Example 1 except that the resin coating layer was formed using the coating liquid having the formulation shown in Table 2. Table 2 shows the physical properties and performance of the obtained developing roller.

(Example 7)
A developing roller was produced in the same manner as in Example 1 except that the resin coating layer was formed using the coating liquid having the formulation shown in Table 2. Table 2 shows the physical properties and performance of the obtained developing roller.

(Example 8)
100 parts by mass of UR8401 (manufactured by Toyobo), 5 parts by mass of coronate HX (manufactured by Nippon Polyurethane), 25 parts by mass of carbon black Printex 35 (manufactured by Degussa) on the roller body provided with the elastic layer made of the urethane foam produced in Example 1. A coating consisting of 100 parts by mass of MEK (methyl ethyl ketone) was applied to a thickness of 50 μm and then cured by heating at 100 ° C. for 1 hour. A developing roller was manufactured by forming a resin coating layer on the obtained roller using a coating liquid having the formulation shown in Table 2. Table 2 shows the physical properties and performance of the obtained developing roller.

(Comparative Example 1)
A developing roller was produced in the same manner as in Example 1 except that the resin coating layer was formed using the coating liquid having the formulation shown in Table 2. Table 2 shows the physical properties and performance of the obtained developing roller.

(Comparative Example 2)
A developing roller was produced in the same manner as in Example 2 except that the resin coating layer was formed using the coating liquid having the formulation shown in Table 2. Table 2 shows the physical properties and performance of the obtained developing roller.

Evaluation methods:
(1) Image evaluation Image forming device: Commercially available laser printer Cartridge color: Cyan (2) Surface roughness Surfcom 590A (manufactured by Tokyo Seimitsu)
(3) Resistance value
R8340A ULTRA HIGH RESISTANCE METER (manufactured by ADVANTEST)
Measurement conditions: 100V applied voltage between shaft and roller surface
Measured in a static state with a load of 500g on both ends of the roller

  As is apparent from Tables 1 and 2, since the toner of the resin coating layer is small in the developing roller of the example, the toner remains on the surface of the developing roller even when the image forming apparatus incorporating the developing roller is used for a long time. It was difficult to adhere and a good image was obtained over a long period of time. Further, in the developing roller of the example, the remaining amount of the unreacted compound in the resin coating layer was sufficiently suppressed, so that the photosensitive drum was not contaminated.

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 coating layer 5 Toner 6 Toner supply roller 7 Photosensitive drum 8 Layering blade 9 Charging roller 10 Transfer roller 11 Cleaning part 12 Cleaning blade

Claims (5)

In a developing roller comprising a shaft, an elastic layer formed on the outer periphery of the shaft, and at least one resin coating layer formed on the outer peripheral surface of the elastic layer,
Made from the resin coating layer, per molecular weight of 1,000 and (meth) electron beam curing resin which is cured by a fluorine-containing copolymer resin and an electron beam non-electron beam-curable containing less than 0 to 0.01 acryloyl group, the A coating liquid containing a non-electron beam curable fluorine-containing copolymer resin and a resin and / or compound having a double bond between carbon atoms that can be polymerized by an electron beam and not containing fluorine. After being applied to the surface, the resin and / or compound having a carbon-carbon double bond polymerizable by the electron beam by electron beam irradiation and not containing fluorine is cured,
The developing roller, wherein the resin and / or compound having a carbon-carbon double bond polymerizable by electron beam and containing no fluorine is a (meth) acrylate monomer and / or oligomer. The non-electron beam curable fluorine-containing copolymer resin is at least one selected from the group consisting of fluorine-containing (meth) acrylate copolymer resins and fluorine-containing olefin copolymer resins. The developing roller according to claim 1.   The developing roller according to claim 1, wherein the resin coating layer contains a carbon-based electronic conductive agent.   The developing roller according to claim 1, wherein the resin coating layer has a thickness of 1 to 500 μm.   An image forming apparatus comprising the developing roller according to claim 1.

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