JP2007248945A - Conductive roller and image forming apparatus having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive roller in which adhesion between an elastic layer and a coating film layer is improved. <P>SOLUTION: The conductive roller 1 includes: a shaft member 2; one or more elastic layers 3 disposed radially outside of the shaft member 2; and one or more coating film layers 4 disposed radially outside of the elastic layer 3. In the conductive roller 1, at least the outermost layer of the elastic layer 3 and the innermost layer of the coating film layer 4 are each formed from an ultraviolet curing resin obtained by curing an ultraviolet curing material mixture by the emission of ultraviolet rays. Then, adhesive (meta)acrylate monomer (A) that is the same type of the material mixture used for the outermost layer of the elastic layer 3 is added to the material mixture used for the innermost layer of the coating film layer 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a conductive roller having an elastic layer and a coating layer, and an image forming apparatus including the conductive roller, and more particularly to a conductive roller having high adhesion between the elastic layer and the coating layer.

  In general, in an electrophotographic image forming apparatus such as a copying machine, a facsimile, or a laser beam printer (LBP), a developing roller, a charging roller, a toner supply roller, a transfer roller, a paper feeding roller, a cleaning roller, and a pressure for fixing. As a roller or the like, a roll-shaped conductive elastic member, that is, a conductive roller is frequently used, and the conductive roller is usually mounted with a shaft member supported by both ends in the length direction, and the shaft member. And one or more elastic layers disposed on the outside in the radial direction. In some cases, the conductive roller further includes a coating layer on the surface of the elastic layer for the purpose of controlling chargeability and adhesion to toner, preventing contamination of the photosensitive drum by the elastic layer, and the like.

  For the shaft member of the conductive roller, various resins such as engineering plastics are used in addition to metals such as iron and stainless steel. The elastic layer of the conductive roller uses an elastomer such as silicone rubber, acrylonitrile-butadiene rubber (NBR), ethylene-propylene-diene rubber (EPDM), epichlorohydrin rubber (ECO), polyurethane, It is manufactured by injecting an elastomer raw material into a mold having a desired cavity shape and heating it to heat cure the elastomer raw material. Further, the coating layer is formed by dipping the roller body composed of the shaft member and the elastic layer into a solvent-based or aqueous coating liquid containing resin or spraying the coating liquid on the roller body, It is formed by drying and curing with hot air. Here, since long time drying is required for the formation of the coating layer, a long drying line is necessary for mass production, and the coating layer requires delicate conductivity and surface condition from its application. However, there is a problem in quality because variations in temperature distribution and air volume in the drying line greatly affect the performance of the coating layer.

  On the other hand, as a method of forming a stable quality coating layer without requiring a long drying line, an ultraviolet curable resin material is applied to the surface of the elastic layer of the roller, and the resin material is cured, A technique for forming a coating layer made of an ultraviolet curable resin on the surface of an elastic layer has been proposed (see Patent Document 1).

JP 2002-310136 A

  Under such circumstances, the present inventors examined a conductive roller using an ultraviolet curable resin for the coating layer and further using an ultraviolet curable resin for the elastic layer. It was found that the elastic layer made of and the coating layer made of an ultraviolet curable resin have poor adhesion. For this reason, when an image forming apparatus provided with such a conductive roller is continuously used, there is a problem that the coating layer is peeled off from the elastic layer, the surface of the roller is scraped, and image defects are likely to occur.

  Therefore, an object of the present invention is to provide a conductive roller which does not require a long drying line for production, has a stable quality coating layer, and has improved adhesion between the elastic layer and the coating layer. is there. Another object of the present invention is to provide an image forming apparatus that can stably form a good image using such a conductive roller.

  As a result of intensive investigations to achieve the above object, the present inventors have determined that an ultraviolet curable raw material mixture used for the elastic layer is added to an ultraviolet curable raw material mixture used for the coating layer disposed on the surface of the elastic layer. By including the same kind of adhesive (meth) acrylate monomer (A), a long drying line is unnecessary for production, and it has a stable quality coating layer, and the adhesion between the elastic layer and the coating layer is It has been found that a conductive roller having high durability and excellent durability can be obtained, and the present invention has been completed.

That is, the conductive roller of the present invention includes a shaft member, one or more elastic layers disposed on the outer side in the radial direction of the shaft member, and one or more coating films disposed on the outer side in the radial direction of the elastic layer. With layers,
At least the outermost layer of the elastic layer and the innermost layer of the coating layer are made of an ultraviolet curable resin obtained by curing an ultraviolet curable raw material mixture by ultraviolet irradiation,
The raw material mixture used for the innermost layer of the coating layer contains the same kind of adhesive (meth) acrylate monomer (A) as the raw material mixture used for the outermost layer of the elastic layer.

  In a preferred example of the conductive roller of the present invention, the raw material mixture used for the innermost layer of the coating layer and the raw material mixture used for the outermost layer of the elastic layer are (meth) acrylate oligomer (B) and / or the adhesiveness ( A (meth) acrylate monomer (C) other than the (meth) acrylate monomer (A) is optionally included, and the adhesive (meth) acrylate monomer (A), the (meth) acrylate oligomer (B), and the adhesive ( The content of the adhesive (meth) acrylate monomer (A) in the total with the (meth) acrylate monomer (C) other than the (meth) acrylate monomer (A) is in the range of 2 to 100% by mass.

  In another preferred embodiment of the conductive roller of the present invention, the adhesive (meth) acrylate monomer (A) is a (meth) acrylate monomer having a heterocyclic group, a (meth) acrylate monomer having a hydroxyl group, and a carboxyl group. At least one polar group-containing (meth) acrylate monomer selected from the group consisting of (meth) acrylate monomers having Here, the (meth) acrylate monomer having a heterocyclic group preferably has a morpholino group.

  The image forming apparatus of the present invention is characterized by using the conductive roller.

  According to the present invention, an adhesive (meth) acrylate monomer (A) of the same type as the ultraviolet curable raw material mixture used for the elastic layer is added to the ultraviolet curable raw material mixture used for the coating layer disposed on the surface of the elastic layer. ), It is possible to provide a conductive roller which does not require a long drying line for production, has a stable coating layer, and has high adhesion between the elastic layer and the coating layer. Further, it is possible to provide an image forming apparatus that includes such a conductive roller and can stably form a good image.

<Conductive roller>
Below, the conductive roller of this invention is demonstrated in detail, referring a figure. FIG. 1 is a cross-sectional view of one embodiment of the conductive roller of the present invention. The conductive roller 1 in the illustrated example includes a shaft member 2, an elastic layer 3 disposed on the outer side in the radial direction of the shaft member 2, and a coating layer 4 disposed on the outer side in the radial direction of the elastic layer 3. Is provided. The conductive roller 1 shown in FIG. 1 has only one elastic layer 3, but the conductive roller of the present invention may have two or more elastic layers. Further, the conductive roller 1 shown in FIG. 1 has only one coating layer 4, but the conductive roller of the present invention can also have two or more coating layers as shown in FIG.

  FIG. 2 is a cross-sectional view of another embodiment of the conductive roller of the present invention. The conductive roller 5 in the illustrated example includes two coating film layers 6 a and 6 b disposed on the radially outer side of the elastic layer 3 instead of the coating film layer 4 shown in FIG. 1. Moreover, the same code | symbol as FIG. 1 shows that it is the same member.

  Here, the conductive roller of the present invention has an ultraviolet curing in which at least the outermost layer of the elastic layer 3 and the innermost layer of the coating layer (coating layers 4 and 6a) are cured by irradiating an ultraviolet curable raw material mixture with ultraviolet irradiation. The raw material mixture made of a mold resin and used for the innermost layer of the coating layer (coating layer 4, 6a) contains the same kind of adhesive (meth) acrylate monomer (A) as the raw material mixture used for the outermost layer of the elastic layer 3 It is characterized by that. In the conductive roller of the present invention, the raw material mixture used for the innermost layer of the coating layer and the raw material mixture used for the outermost layer of the elastic layer contain the same kind of adhesive (meth) acrylate monomer (A), The affinity between the elastic layer and the coating layer is improved, and the adhesiveness between the elastic layer and the coating layer is greatly improved. Therefore, an image forming apparatus provided with such a conductive roller can solve problems related to the durability of the roller such as peeling of a coating film layer observed during continuous use, and can stably form a good image.

  As the adhesive (meth) acrylate monomer (A) used in the raw material mixture for the outermost layer of the elastic layer and the raw material mixture for the innermost layer of the coating layer, a (meth) acrylate monomer having a heterocyclic group, a hydroxyl group Preferred examples include polar group-containing (meth) acrylate monomers such as (meth) acrylate monomers having a carboxyl group and (meth) acrylate monomers having a carboxyl group. These polar group-containing (meth) acrylate monomers are not particularly limited as long as the same kind of (meth) acrylate monomer is used in the outermost layer of the elastic layer and the innermost layer of the coating layer, and may be used alone or in combination. You may use combining more than a seed.

  In the (meth) acrylate monomer having a heterocyclic group, examples of the heterocyclic group include a morpholino group, an isocyanurate group, a furyl group, and a phthaloyl group. Among these, a morpholino group is preferable. Specific examples of the (meth) acrylate monomer having a heterocyclic group include morpholine (meth) acrylate, tris (2-hydroxylethyl) isocyanurate tri (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2 -Acryloyloxyethyl hexahydrophthalic acid and the like, and among these, morpholine (meth) acrylate is preferred. These (meth) acrylate monomers having a heterocyclic group may be used alone or in combination of two or more.

  Specific examples of the hydroxyl group-containing (meth) acrylate monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and pentaerythritol tri (meth). Acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-acryloyloxyethyl acid phosphate, and the like. These (meth) acrylate monomers having a hydroxyl group may be used alone or in combination of two or more.

  Specific examples of the (meth) acrylate monomer having a carboxyl group include β- (meth) acryloyloxyethyl hydrogen succinate, β- (meth) acryloyloxypropyl hydrogen succinate, β- (meth) acryloyloxy Ethyl hydrogen phthalate, β- (meth) acryloyloxypropyl hydrogen phthalate, β- (meth) acryloyloxy ethyl hydrogen tetrahydrophthalate, β- (meth) acryloyloxypropyl hydrogen tetrahydrophthalate, β- (meth) acryloyloxy Examples include ethyl hydrogen hexahydrophthalate, β- (meth) acryloyloxypropyl hydrogen hexahydrophthalate, β-tris ((meth) acryloyloxymethyl) ethyl hydrogen phthalate, etc. It is done. These (meth) acrylate monomers having a carboxyl group may be used alone or in combination of two or more.

  The ultraviolet curable raw material mixture used for the formation of the outermost layer of the elastic layer is a (meth) acrylate oligomer (B), a (meth) acrylate monomer (C) other than the adhesive (meth) acrylate monomer (A), It is preferable to contain a photopolymerization initiator, a photosensitizer, a conductive agent, and the like, and the ultraviolet curable raw material mixture used for forming the innermost layer of the coating layer is further a (meth) acrylate oligomer (B). It is preferable to contain a (meth) acrylate monomer (C) other than the adhesive (meth) acrylate monomer (A), a photopolymerization initiator, a photosensitizer, a diluting solvent, a conductive agent, fine particles, and the like. In the conductive roller of the present invention, the elastic layer other than the outermost layer is not particularly limited, and may be the same as or different from the outermost layer. In the conductive roller of the present invention, other than the innermost layer. The coating layer is not particularly limited and may be the same as or different from the innermost layer.

  As the (meth) acrylate oligomer (B) suitable for use in the ultraviolet curable raw material mixture, urethane (meth) acrylate oligomer, epoxy (meth) acrylate oligomer, ether (meth) acrylate oligomer, ester Examples include (meth) acrylate oligomers, polycarbonate-based (meth) acrylate oligomers, fluorine-based (meth) acrylate oligomers, and silicone-based (meth) acrylate oligomers. The (meth) acrylate oligomer (B) 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. It can be synthesized by reaction with (meth) 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.

  The ultraviolet curable raw material mixture may contain a (meth) acrylate monomer (C) other than the adhesive (meth) acrylate monomer (A) as a reactive diluent, and the (meth) acrylate monomer (C ) As ethyl (meth) acrylate, isobutyl (meth) acrylate, n-butyl (meth) acrylate, isoamyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, lauryl (meth) acrylate, isomyristyl (meth) Examples include acrylate, stearyl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, and the like. These (meth) acrylate monomers (C) may be used individually by 1 type, and may be used in combination of 2 or more type.

  In the conductive roller of the present invention, in the raw material mixture for the outermost layer of the elastic layer and the innermost layer of the coating layer, the adhesive (meth) acrylate monomer (A), the (meth) acrylate oligomer (B) and the above adhesive property ( The ratio of the adhesive (meth) acrylate monomer (A) to the total of (meth) acrylate monomers (C) other than the (meth) acrylate monomer (A) is the adhesion between the outermost layer of the elastic layer and the innermost layer of the coating layer. From the viewpoint of enhancing the properties, a range of 2 to 100% by mass is preferable and a range of 5 to 50% by mass is more preferable. When the content of the adhesive (meth) acrylate monomer (A) is less than 2% by mass, it is difficult to ensure the adhesion between the outermost layer of the elastic layer and the innermost layer of the coating layer.

  The ultraviolet curable raw material mixture preferably contains a photopolymerization initiator, and the photopolymerization initiator is irradiated with ultraviolet rays so that the (meth) acrylate monomers (A), (C) and ( It has an action of initiating polymerization of the (meth) acrylate oligomer (B). Examples of the photopolymerization initiator include 4-dimethylaminobenzoic acid, 4-dimethylaminobenzoic acid ester, 2,2-dimethoxy-2-phenylacetophenone, acetophenone diethyl ketal, alkoxyacetophenone, benzyldimethyl ketal, benzophenone and 3,3. -Dimethyl-4-methoxybenzophenone, benzophenone derivatives such as 4,4-dimethoxybenzophenone, 4,4-diaminobenzophenone, benzoylalkyl benzoate, bis (4-dialkylaminophenyl) ketone, 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-hydroxycyclohexyl 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, etc. It is done. These photoinitiators may be used individually by 1 type, and may use 2 or more types together. The blending amount of the photopolymerization initiator in the ultraviolet curable raw material mixture is 0.2 with respect to a total of 100 parts by mass of the (meth) acrylate monomers (A), (C) and the (meth) acrylate oligomer (B). A range of ˜5.0 parts by mass is preferred. When the blending amount of the photopolymerization initiator is 0.2 parts by mass or less, the effect of initiating UV curing of the raw material mixture is small, while when it exceeds 5.0 parts by mass, the effect of initiating UV curing is saturated, The cost of the raw material mixture increases.

  Further, when the ultraviolet curable raw material mixture contains a photopolymerization initiator, it may contain a photosensitizer, and the photosensitizer absorbs energy by being irradiated with ultraviolet rays. The energy or electrons move to the polymerization initiator and have an action of initiating polymerization. Examples of the photosensitizer include p-dimethylaminobenzoic acid isoamyl ester.

  In order to impart conductivity to the coating layer and the elastic layer, a conductive agent may be added to the ultraviolet curable raw material mixture, and examples of the conductive agent include an ionic conductive agent and an electronic conductive agent. It is done. Examples of ionic conducting agents include tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium, hexadecyltrimethylammonium, benzyltrimethylammonium, and modified fatty acid dimethylethylammonium perchlorate, chlorate, hydrochloride, bromate, iodine Ammonium salts such as acid salts, borofluoride salts, sulfate salts, ethyl sulfate salts, carboxylate salts, sulfonate salts; alkali metals such as lithium, sodium, potassium, calcium, magnesium, and perchloric acids of alkaline earth metals Salt, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, trifluoromethyl sulfate, sulfonate, and the like. Conductive carbon such as acetylene black, SAF, I Carbon black for rubber such as AF, HAF, FEF, GPF, SRF, FT, MT, carbon black for color with oxidation treatment, pyrolytic carbon black, natural graphite, artificial graphite, antimony-doped tin oxide, ITO, oxidation Metal oxides such as tin, titanium oxide and zinc oxide, metals such as nickel, copper, silver and germanium, conductive polymers such as polyaniline, polypyrrole and polyacetylene, carbon whiskers, graphite whiskers, titanium carbide whiskers, conductive potassium titanate Examples include whiskers, conductive barium titanate whiskers, conductive titanium oxide whiskers, and conductive zinc oxide whiskers. The usage-amount of these electrically conductive agents can be suitably adjusted so that a coating-film layer and an elastic layer may have desired electroconductivity.

  Further, the ultraviolet curable raw material mixture used for forming the coating layer may contain an organic solvent such as ether, ketone or ester as a diluent solvent, and the organic solvent may be propylene glycol monomethyl ether acetate (PMA). ), Methyl ethyl ketone (MEK), acetone, butyl lactate and the like. These diluent solvents may be used alone or in combination of two or more.

  The ultraviolet curable raw material mixture used for forming the coating layer may further contain fine particles. By including fine particles in the raw material mixture of the coating layer, appropriate minute irregularities can be formed on the surface of the conductive roller. As the fine particles, inorganic fine particles such as fine particles made of rubber, urethane or synthetic resin, fine particles made of carbon and silica fine particles are preferable. Silicone rubber, silicone resin, fluororesin, urethane resin, polyolefin resin, epoxy resin, polystyrene resin Epoxy resin, polystyrene resin, urethane acrylate, melamine resin, phenol resin, (meth) acrylic resin, glassy carbon fine particles and silica fine particles are particularly preferable. These fine particles may be used alone or in combination of two or more. Moreover, the compounding quantity of this microparticles | fine-particles has the range of 0.1-100 mass parts with respect to a total of 100 mass parts of the said (meth) acrylate monomer (A), (C) and (meth) acrylate oligomer (B). preferable.

  The total thickness of the elastic layer is preferably 800 μm or more, and the thickness per elastic layer is preferably 1 mm or less. Since the elastic layer can be laminated, there is no limit on the upper limit of the thickness of the entire elastic layer. Here, if the thickness of the entire elastic layer is 800 μm or more, the conductive roller has sufficient elasticity and the damage to the toner is sufficiently small, while the thickness per elastic layer is 1 mm or less. In this case, the elastic layer can be sufficiently cured.

  On the other hand, the thickness of the coating layer is preferably in the range of 1 μm to 50 μm. If the thickness of the coating layer is less than 1 μm, the effect of disposing the coating layer is small, and if it exceeds 50 μm, the surface of the conductive roller becomes hard and the flexibility is impaired.

  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. If the Asker C hardness of the elastic layer exceeds 80 degrees, the contact area between the conductive roller and the photosensitive drum may be reduced, and good development may not be performed. Also, the toner may be damaged and the photosensitive drum or the stratified blade may be damaged. The toner sticks and 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.

  The shaft member of the conductive roller of the present invention is not particularly limited as long as it has good conductivity. For example, a metal core made of a metal solid body, a metal cylindrical body hollowed inside, or a high rigidity Examples thereof include a cylindrical body made of resin, and a composite body in which a high-rigidity resin is arranged on the outer periphery of a core metal. In addition, when using highly rigid resin for a shaft member, it is preferable to ensure sufficient electroconductivity by adding and disperse | distributing a electrically conductive agent to highly rigid resin. Here, as the conductive agent dispersed in the high-rigidity resin, carbon black powder, graphite powder, carbon fiber, metal powder such as aluminum, copper and nickel, metal oxide powder such as tin oxide, titanium oxide and zinc oxide, conductive A powdery conductive agent such as conductive glass powder is preferred. These electrically conductive agents may be used individually by 1 type, and may be used in combination of 2 or more type. Although the compounding quantity of this electrically conductive agent is not restrict | limited in particular, The range of 5-40 mass% is preferable with respect to the whole highly rigid resin, and the range of 5-20 mass% is still more preferable.

  Examples of the material for the metal core bar and the metal cylinder include iron, stainless steel, and aluminum. The material of the high-rigidity resin base material is polyacetal, polyamide 6, polyamide 6 · 6, polyamide 12, polyamide 4 · 6, polyamide 6 · 10, polyamide 6 · 12, polyamide 11, polyamide MXD6, polybutylene. Terephthalate, polyphenylene oxide, polyphenylene sulfide, polyethersulfone, polycarbonate, polyimide, polyamideimide, polyetherimide, polysulfone, polyetheretherketone, polyethylene terephthalate, polyarylate, liquid crystal polymer, polytetrafluoroethylene, polypropylene, ABS resin, polystyrene , Polyethylene, melamine resin, phenol resin, silicone resin and the like. Among these, polyacetal, polyamide 6/6, polyamide MXD6, polyamide 6/12, polybutylene terephthalate, polyphenylene ether, polyphenylene sulfide, and polycarbonate are preferable. These high-rigidity resins may be used alone or in combination of two or more.

  The conductive roller 1 of the present invention is formed by, for example, applying the elastic layer raw material mixture to the outer surface of the shaft member 2 and then irradiating with ultraviolet rays to form the elastic layer 3, and then the outer surface of the elastic layer 3. After the coating film layer raw material mixture is applied, the coating film layer 4 is formed by irradiating with ultraviolet rays. The conductive roller 5 of the present invention can also be produced in the same manner as the conductive roller 1 except that the coating layer is repeatedly formed. Therefore, the conductive roller of the present invention does not require a long drying line for production, and has a coating layer having a stable quality. In addition, as a method of applying the elastic layer raw material mixture to the outer surface of the shaft member and a method of applying the coating layer raw material mixture to the outer surface of the elastic layer, spray method, roll coater method, dipping method, die coating method Etc. Examples of the light source used for ultraviolet irradiation include a mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, and a xenon lamp. The conditions for ultraviolet irradiation are appropriately selected according to the components, composition, coating amount, and the like contained in the elastic layer raw material mixture and the coating layer raw material mixture, and the irradiation intensity and the integrated light amount may be adjusted as appropriate.

  The conductive roller of the present invention described above can be used as a developing roller, a charging roller, a toner supply roller, a transfer roller, a paper feed roller, a cleaning roller, a fixing pressure roller, and the like of an image forming apparatus.

<Image forming apparatus>
The image forming apparatus of the present invention includes the conductive roller described above. The image forming apparatus of the present invention is not particularly limited except that the conductive 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. 3 is a partial cross-sectional view of one embodiment of the image forming apparatus of the present invention. The image forming apparatus of the illustrated example supplies a photosensitive drum 7 that holds an electrostatic latent image, a charging roller 8 that is positioned in the vicinity of the photosensitive drum 7 (upward in the drawing) and charges the photosensitive drum 7, and toner 9. A toner supply roller 10, a developing roller 11 disposed between the toner supply roller 10 and the photosensitive drum 7, a developing blade 12 provided in the vicinity of the developing roller 11 (upward in the drawing), and a photosensitive drum. 7 is provided with a transfer roller 13 positioned in the vicinity (lower in the drawing) 7 and a cleaning roller 14 disposed adjacent to the photosensitive drum 7. The image forming apparatus of the present invention can further include known components (not shown) that are normally used in the image forming apparatus.

  In the illustrated image forming apparatus, the charging roller 8 is brought into contact with the photosensitive drum 7 and a voltage is applied between the photosensitive drum 7 and the charging roller 8 to charge the photosensitive drum 7 to a constant potential. Then, an electrostatic latent image is formed on the photosensitive drum 7 by an exposure machine (not shown). Next, the photosensitive drum 7, the toner supply roller 10, and the developing roller 11 rotate in the direction of the arrow in the drawing, so that the toner 9 on the toner supply roller 10 is sent to the photosensitive drum 7 through the developing roller 11. It is done. The toner 9 on the developing roller 11 is adjusted to a uniform thin layer by the developing blade 12 and rotates while the developing roller 11 and the photosensitive drum 7 are in contact with each other, so that the toner 9 is transferred from the developing roller 11 to the photosensitive drum 7. It adheres to the electrostatic latent image and the latent image becomes visible. The toner 9 adhered to the latent image is transferred to a recording medium such as paper by the transfer roller 13, and the toner 9 remaining on the photosensitive drum 7 after the transfer is removed by the cleaning roller 14. Here, in the image forming apparatus of the present invention, for example, at least one of the charging roller 8, the toner supply roller 10, the developing roller 11, the transfer roller 13, and the cleaning roller 14, for example, the elastic layer 3 and the coating layer described above. By using the conductive roller 5 having high adhesiveness with 6a and having excellent durability, an excellent image can be stably formed.

  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.

(Examples 1-6 and Comparative Examples 3-5)
A raw material mixture for the elastic layer A having the composition shown in Table 1 is applied to a polybutylene terephthalate (PBT) resin roller base material (shaft member) having an outer diameter of 17.0 mm with a metal shaft having an outer diameter of 6.0 mm inserted by a die coater. The coating was applied at a thickness of 750 μm, and UV irradiation was performed for 5 seconds at a UV irradiation intensity of 700 mW / cm ² while rotating in a nitrogen atmosphere. By performing this operation twice, a roller body provided with an elastic layer A having a thickness of 1500 μm was obtained. On the surface of the obtained roller main body, the raw material mixture for coating layer A having the composition shown in Table 1 was applied by a roll coater, and irradiated with UV at a UV irradiation intensity of 700 mW / cm ² for 5 seconds while rotating in a nitrogen atmosphere. Then, the conductive roller for coating layer B having the composition shown in Table 1 is disposed in the same manner as coating layer A, and the thickness of the coating layer consisting of two layers is in the range of 10 to 30 μm. Got.

(Example 7 and Comparative Examples 1-2)
Using the raw material mixture for elastic layer A and the raw material mixture for coating layer B having the composition shown in Table 1, the conductive layer having the structure shown in FIG. 1 and having an elastic layer having a thickness of 1500 μm and a coating layer having a thickness of 10 μm A neutral roller was produced in the same manner as in Example 1.

  Next, in order to evaluate the adhesion between the elastic layer and the coating film layer of the obtained conductive roller, the conductive roller is incorporated into an image forming apparatus, and the surface scraping and coating film layer after printing 5000 sheets The state of peeling was tested. The results are shown in Table 1.

* 1 Urethane acrylate, manufactured by Nippon Synthetic Chemical Co., Ltd.
* 2 Isomyristyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd.
* 3 Shin-Nakamura Chemical Co., Ltd., β-acryloyloxyethyl hydrogen succinate, CH ₂ = CHCOOCH ₂ CH ₂ OCOCH ₂ CH ₂ COOH.
* 4 Morphine acrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.
* 5 2-hydroxypropyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd.
* 6 Tris (2-hydroxyethyl) isocyanurate triacrylate, manufactured by Sartomer.
* 7 1-hydroxycyclohexyl phenyl ketone, manufactured by Ciba Specialty Chemicals.
* 8 Sodium perchlorate polyol complex salt, manufactured by Akishima Chemical Co., Ltd.
* 9 Urethane acrylate, manufactured by Nippon Synthetic Chemical Co., Ltd.
* 10 Propylene glycol monomethyl ether acetate.
* 11 Urethane acrylate, manufactured by Kyoeisha Chemical Co., Ltd.
* 12 1,6-hexanediol diacrylate, manufactured by Kyoeisha Chemical Co., Ltd.
* 13 Carbon, manufactured by Mitsubishi Chemical Corporation.
* 14 2,4-Diethylthioxanthone manufactured by Nippon Kayaku Co., Ltd.
* 15 Isoamyl ester of p-dimethylaminobenzoic acid manufactured by Nippon Kayaku Co., Ltd.

  From Comparative Examples 1 to 5, the adhesiveness between the elastic layer and the coating layer is improved only by using the adhesive acrylate monomer only in either the elastic layer or the coating layer (Comparative Examples 2 and 4). In addition, when the adhesive acrylate monomers contained in the elastic layer and the coating layer are different (Comparative Examples 3 and 5), although the adhesiveness is slightly improved, the durability of the conductive roller cannot be sufficiently ensured. I understand that.

  On the other hand, the conductive roller of the present invention uses the same kind of adhesive acrylate monomer for the elastic layer and the coating layer, so that both the surface scraping after continuous printing and the peeling of the coating layer have good results. It turns out that the adhesiveness of a layer and a coating-film layer is high (Examples 1-7).

It is sectional drawing of one embodiment of the electroconductive roller of this invention. It is sectional drawing of the other embodiment of the conductive roller of this invention. 1 is a partial cross-sectional view of an embodiment of an image forming apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive roller 2 Shaft member 3 Elastic layer 4 Paint film layer 5 Conductive roller 6a Paint film layer 6b Paint film layer 7 Photosensitive drum 8 Charging roller 9 Toner 10 Toner supply roller 11 Developing roller 12 Developing blade 13 Transfer roller 14 Cleaning roller

Claims (5)

In a conductive roller comprising a shaft member, one or more elastic layers disposed radially outward of the shaft member, and one or more coating layers disposed radially outward of the elastic layer,
At least the outermost layer of the elastic layer and the innermost layer of the coating layer are made of an ultraviolet curable resin obtained by curing an ultraviolet curable raw material mixture by ultraviolet irradiation,
The conductive roller, wherein the raw material mixture used for the innermost layer of the coating layer contains the same kind of adhesive (meth) acrylate monomer (A) as the raw material mixture used for the outermost layer of the elastic layer.   The raw material mixture used for the innermost layer of the coating layer and the raw material mixture used for the outermost layer of the elastic layer are (meth) acrylate oligomer (B) and / or (meta) other than the adhesive (meth) acrylate monomer (A). ) Acrylate monomer (C) optionally, and other than the adhesive (meth) acrylate monomer (A), the (meth) acrylate oligomer (B) and the adhesive (meth) acrylate monomer (A) The conductive roller according to claim 1, wherein the content of the adhesive (meth) acrylate monomer (A) in the total with the acrylate monomer (C) is in the range of 2 to 100% by mass.   The adhesive (meth) acrylate monomer (A) is selected from the group consisting of a (meth) acrylate monomer having a heterocyclic group, a (meth) acrylate monomer having a hydroxyl group, and a (meth) acrylate monomer having a carboxyl group. The conductive roller according to claim 1, wherein the conductive roller is at least one polar group-containing (meth) acrylate monomer.   The conductive roller according to claim 3, wherein the (meth) acrylate monomer having a heterocyclic group has a morpholino group.   An image forming apparatus comprising the conductive roller according to claim 1.

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