JP2009145798A - Conductive roller and image forming apparatus equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive roller which does not need a long drying line for its manufacture, which has a coating film layer of stabilized quality and improved durability. <P>SOLUTION: The conductive roller 1 is equipped with a shaft member 2, an elastic layer 3 disposed on the outside in the radial direction of the shaft member 2, and one or more coating film layers 4 disposed on the outside in a radial direction of the elastic layer 3. At least the coating film layer 4, adjacent to the elastic layer 3, is constituted of ultraviolet-curing type resin obtained, by curing material for a coating film layer that contains (meth)acrylate oligomer (A), (meth)acrylate monomer (B) and photoinitiator (C) by the irradiation of ultraviolet and having an elastic modulus of 100 MPa or smaller. <P>COPYRIGHT: (C)2009,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 improved durability and the conductive roller, and providing a good image. The present invention relates to an image forming apparatus that can be formed.

  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. The conductive roller has a coating layer on the surface of the elastic layer for the purpose of improving the hardness of the roller, controlling chargeability and adhesion to toner, preventing contamination of the photosensitive drum by the elastic layer, and the like. There is a case to prepare.

  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, The elastic layer is manufactured by injecting an elastomer raw material into a mold having a desired cavity shape and heat curing. 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 has subtle electrical conductivity and surface condition from its use. However, there is a problem in quality because variations in temperature distribution and air flow 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 JP 2002-310136 A).

JP 2002-310136 A

  However, since a coating layer formed by UV curing a UV curable resin material is usually harder than an elastic layer, a conductive roller having such a coating layer is used in an image forming apparatus. There was a problem that the coating layer was cracked or scraped during use, and the durability of the roller was lowered. In addition, when the hardness of the coating layer is too high, there is a problem that adjacent members such as a photoreceptor are scraped.

  Accordingly, an object of the present invention is to provide a conductive roller which does not require a long drying line in the production process, has a stable quality coating layer, and has improved durability. Another object of the present invention is to provide an image forming apparatus capable of stably forming a good image using such a conductive roller.

  As a result of earnest studies to achieve the above object, the present inventor, as a result, in a conductive roller having a coating layer disposed on the surface of the elastic layer, a (meth) acrylate oligomer and a (meth) acrylate on the coating layer. Uses an ultraviolet curable resin obtained by curing a raw material composition containing a monomer and a photopolymerization initiator by ultraviolet irradiation, and has excellent durability by controlling the elastic modulus of the coating layer to a certain value or less. The inventors have found that a conductive roller can be obtained and have completed the present invention.

That is, the conductive roller of the present invention includes a shaft member, an elastic layer disposed on the outer side in the radial direction of the shaft member, and one or more coating layers disposed on the outer side in the radial direction of the elastic layer. Prepared,
At least the coating layer adjacent to the elastic layer is cured by irradiating the coating layer material containing (meth) acrylate oligomer (A), (meth) acrylate monomer (B) and photopolymerization initiator (C) with ultraviolet irradiation. Further, it is characterized by comprising an ultraviolet curable resin having an elastic modulus of 100 MPa or less.

  In the conductive roller of the present invention, it suffices that at least the coating layer adjacent to the elastic layer is formed from this ultraviolet curable resin, and when the conductive roller has two or more coating layers, The other coating layer is not limited to this.

  In the conductive roller of the present invention, the total thickness of the coating layers is preferably 5 μm or more.

  In a preferred example of the conductive roller of the present invention, the (meth) acrylate oligomer (A) has 2 to 4 functional groups.

  In the conductive roller of the present invention, the (meth) acrylate monomer (B) includes (meth) acrylate containing acryloylmorpholine, N, N-diethylaminoethyl methacrylate, isobornyl acrylate, phenoxyethyl acrylate, and silicon or fluorine. Monomers are preferred.

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

  According to the present invention, in the conductive roller in which one or more coating layers are disposed on the surface of the elastic layer, at least the coating layer adjacent to the elastic layer includes (meth) acrylate oligomer (A), (meth) By using an ultraviolet curable resin with an elastic modulus of 100 MPa or less, which is obtained by curing a raw material mixture containing an acrylate monomer (B) and a photopolymerization initiator (C) by ultraviolet irradiation, durability against scraping and cracking is improved. An electrically conductive roller can be provided. 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 an example of a 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. In addition, although the conductive roller 1 shown in FIG. 1 has only one coating layer 4, the conductive roller of the present invention may have two or more coating layers.

  In the conductive roller of the present invention, at least the coating layer 4 adjacent to the elastic layer 3 includes a (meth) acrylate oligomer (A), a (meth) acrylate monomer (B), and a photopolymerization initiator (C). It is made of an ultraviolet curable resin obtained by curing the layer raw material by ultraviolet irradiation, and the ultraviolet curable resin has an elastic modulus of 100 MPa or less. Here, when the elastic modulus of the ultraviolet curable resin forming the coating layer is 100 MPa or less, the hardness of the coating layer can be reduced. For this reason, the durability of the conductive roller is improved, and the occurrence of cracking or scraping of the coating layer can be prevented. In general, the conductive roller is in direct contact with an adjacent member such as a photoconductor during printing and rotates while appropriately niping. Therefore, if the elastic modulus of the coating layer is too high, the adjacent member such as the photoconductor is You can cut it. However, in the conductive roller of the present invention, since the elastic modulus of the ultraviolet curable resin that forms at least the coating layer adjacent to the elastic layer is 100 MPa or less, it is possible to suppress scraping of adjacent members such as a photoconductor. . In the case where the conductive roller of the present invention has a plurality of coating layers, the elastic modulus of the ultraviolet curable resin for forming the outermost coating layer is set to 100 MPa or less, so that The scraping of the adjacent member can be further suppressed.

  Further, as described above, the conductive roller of the present invention may have only one coating layer, or may have two or more coating layers. The total thickness is preferably 5 μm or more, more preferably 5 to 50 μm. If the total thickness of the coating layer is 5 μm or more, deformation of the coating layer at the time of the nip can be sufficiently secured, so that the coating layer is prevented from being scraped. In addition, when the total thickness of the coating layer is less than 5 μm, the effect of disposing the coating layer is small.

The (meth) acrylate oligomer (A) used as the raw material for the coating layer is an oligomer having one or more acryloyloxy groups (CH ₂ ═CHCOO—) or methacryloyloxy groups (CH ₂ ═C (CH ₃ ) COO—). It is. (Meth) acrylate oligomer (A) includes urethane (meth) acrylate oligomer, epoxy (meth) acrylate oligomer, ether (meth) acrylate oligomer, ester (meth) acrylate oligomer, polycarbonate (meth) acrylate oligomer , Fluorine-based (meth) acrylate oligomers, silicone-based (meth) acrylate oligomers, and the like. Among these, urethane-based (meth) acrylate oligomers are preferable. (Meth) acrylate oligomer (A) 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. In addition, a (meth) acrylate oligomer (A) may be used individually by 1 type, and may be used in combination of 2 or more type.

  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 having 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 (meth) acrylate oligomer (A) is not particularly limited, but the weight average molecular weight is preferably 4500 or more, more preferably 6000 or more, and the weight average molecular weight is 40000 or less. preferable. Here, if the weight average molecular weight is 4500 or more, elongation characteristics can be imparted to the coating layer, and the durability of the roller is improved. On the other hand, when the weight average molecular weight exceeds 40,000, the adhesiveness of the coating layer is lowered, and workability may be lowered.

  The (meth) acrylate oligomer (A) is not particularly limited, but the number of functional groups is preferably 2 to 4, and more preferably 2 to 3. Here, the functional group refers to an acryloyloxy group and a methacryloyloxy group, and the number of functional groups refers to the average number of functional groups. If the number of functional groups of the (meth) acrylate oligomer (A) is in the specific range, the crosslinking density of the ultraviolet curable resin is lowered, and the elastic modulus can be reduced. In addition, when the number of functional groups of the (meth) acrylate oligomer (A) is less than 2, not only the reaction rate is lowered, but also the reactive sites are decreased, so that unreacted substances are increased, and the adjoining member such as the photoconductor is increased. Contamination may occur. On the other hand, when the number of functional groups of the (meth) acrylate oligomer (A) exceeds 4, not only the hardness becomes too high but also the brittleness may occur and the coating layer may be scraped off.

The (meth) acrylate monomer (B) used for the coating layer material is a monomer having one or more acryloyloxy groups (CH ₂ ═CHCOO—) or methacryloyloxy groups (CH ₂ ═C (CH ₃ ) COO—). It acts as a reactive diluent, that is, it can be cured with ultraviolet rays, and the viscosity of the raw material for the coating layer can be reduced. The molecular weight of the (meth) acrylate monomer (B) is not particularly limited, but is preferably 70 to 2000. The (meth) acrylate monomer (B) may be used alone or in combination of two or more.

  The (meth) acrylate monomer (B) preferably has 1 to 4 functional groups. Here, the functional group refers to an acryloyloxy group and a methacryloyloxy group, and the number of functional groups refers to the average number of functional groups. If the number of functional groups of the (meth) acrylate monomer (B) exceeds 4, the crosslink density in the ultraviolet curable resin increases, which may increase the elastic modulus.

  The (meth) acrylate monomer (B) preferably has a bulky substituent or polar group in addition to the acryloyloxy group or methacryloyloxy group. Since the (meth) acrylate monomer has a bulky substituent or polar group, the polymer chain after polymerization becomes three-dimensionally bulky, or the polar group interaction in the polymer chain becomes stronger. Crystallinity decreases. In general, amorphous polymers tend to have better elongation characteristics than crystalline polymers, so (meth) acrylate monomers with bulky substituents or polar groups have a lower elastic modulus of UV curable resins. It is considered effective. Specific examples of the (meth) acrylate monomer (B) preferably include acryloylmorpholine, N, N-diethylaminoethyl methacrylate, isobornyl acrylate, and phenoxyethyl acrylate. In addition, a (meth) acrylate monomer may be used individually by 1 type, and may be used in combination of 2 or more type.

  The (meth) acrylate monomer (B) may contain silicon or fluorine in the molecule. When the (meth) acrylate monomer has silicon or fluorine in the molecule, the flexibility of the resin can be increased without increasing the friction coefficient of the surface of the ultraviolet curable resin. This is considered due to the water repellency and oil repellency of silicon or fluorine. Thereby, the elastic modulus of the ultraviolet curable resin can be reduced.

  As the (meth) acrylate monomer containing silicon, both-end-reactive silicone oils, one-end-reactive silicone oils, and (meth) acryloxyalkylsilanes are preferable. Here, both terminal reactive silicone oils and one terminal reactive silicone oils refer to those having an acryloyloxy group or a methacryloyloxy group introduced as a reactive terminal.

（式中、ｍは繰り返し単位数である）で表されるシリコーンオイルが挙げられる。該両末端反応性シリコーンオイル類としては、市販品を利用することができ、例えば、信越化学工業(株)製の品名「Ｘ-２２-１６４Ａ」（粘度25mm²/s、官能基当量860g/mol）、品名「Ｘ-２２-１６４Ｂ」（粘度55mm²/s、官能基当量1630g/mol）、品名「Ｘ-２２-１６４Ｃ」（粘度90mm²/s、官能基当量2370g/mol）、東レ・ダウコーニング・シリコーン(株)製の品番「ＢＸ１６-１５２Ｂ」（粘度40cs/25℃、メタクリル基当量1300g/mol、25℃での比重0.97）、品番「ＢＹ１６-１５２」（粘度85cs/25℃、メタクリル基当量2800g/mol、25℃での比重0.97）、品番「ＢＸ２-１５２Ｃ」（粘度330cs/25℃、メタクリル基当量5100g/mol、25℃での比重0.97）等を用いることができる。 Examples of the both-end reactive silicone oils include the following formula (I):

(Wherein, m is the number of repeating units). Commercially available products can be used as the both-end-reactive silicone oils, for example, “X-22-164A” (viscosity 25 mm ² / s, functional group equivalent 860 g / s) manufactured by Shin-Etsu Chemical Co., Ltd. mol), product name “X-22-164B” (viscosity 55 mm ² / s, functional group equivalent 1630 g / mol), product name “X-22-164C” (viscosity 90 mm ² / s, functional group equivalent 2370 g / mol), Toray・ Product number “BX16-152B” manufactured by Dow Corning Silicone Co., Ltd. (viscosity 40cs / 25 ° C., methacryl group equivalent 1300 g / mol, specific gravity 0.97 at 25 ° C.), product number “BY16-152” (viscosity 85cs / 25 ° C. Methacryl group equivalent 2800 g / mol, specific gravity 0.97 at 25 ° C.), product number “BX2-152C” (viscosity 330 cs / 25 ° C., methacryl group equivalent 5100 g / mol, specific gravity 0.97 at 25 ° C.), etc. can be used.

（式中、Ｒ¹は、メチル基又はブチル基であり、ｎは繰り返し単位数である）で表されるシリコーンオイル及び下記式(III)：

で表されるシリコーンオイルが挙げられる。該片末端反応性シリコーンオイル類としては、市販品を利用することができ、例えば、信越化学工業(株)製の品名「Ｘ-２４-８２０１」（粘度25mm²/s、官能基当量2100g/mol）、品名「Ｘ-２２-１７４ＤＸ」（粘度60mm²/s、官能基当量4600g/mol）、品名「Ｘ-２２-２４２６」（粘度180mm²/s、官能基当量12000g/mol）、東レ・ダウコーニング・シリコーン(株)製の品番「ＢＸ１６-１２２Ａ」（粘度5cs/25℃、屈折率1.417、25℃での比重0.92）等を用いることができる。 Examples of the one-end reactive silicone oils include the following formula (II):

(Wherein R ¹ is a methyl group or a butyl group, and n is the number of repeating units) and the following formula (III):

The silicone oil represented by these is mentioned. Commercially available products can be used as the one-terminal reactive silicone oils, for example, “X-24-8201” (viscosity 25 mm ² / s, functional group equivalent 2100 g / s) manufactured by Shin-Etsu Chemical Co., Ltd. mol), product name “X-22-174DX” (viscosity 60 mm ² / s, functional group equivalent 4600 g / mol), product name “X-22-2426” (viscosity 180 mm ² / s, functional group equivalent 12000 g / mol), Toray A product number “BX16-122A” manufactured by Dow Corning Silicone Co., Ltd. (viscosity 5cs / 25 ° C., refractive index 1.417, specific gravity 0.92 at 25 ° C.) or the like can be used.

Further, the (meth) acryloxyalkylsilanes include 3-methacryloxypropyldichloromethylsilane [CH ₂ ═C (CH ₃ ) COO (CH ₂ ) ₃ SiCl ₂ CH ₃ ], 3-acryloxypropyl dimethoxymethyl. silane _{[CH 2 = CHCOO (CH 2} ) 3 Si (OCH 3) 2 CH 3], 3- acryloxypropyltrimethoxysilane _{[CH 2 = CHCOO (CH 2} ) 3 Si (OCH 3) 3], 3- methacryl b propyl dimethoxy methyl silane _{[CH 2 = C (CH 3} ) COO (CH 2) 3 Si (OCH 3) 2 CH 3], 3- methacryloxypropyl trimethoxysilane _{[CH 2 = C (CH 3} ) COO (CH _{2) 3 Si (OCH 3)} 3], 3- methacryloxypropyl diethoxymethyl silane _{[CH 2 = C (CH 3} ) COO (CH 2) 3 Si (OC 2 H 5) 2 CH 3], 3- methacrylonitrile Shi propyltriethoxysilane _{[CH 2 = C (CH 3} ) COO (CH 2) 3 Si (OC 2 H 5) 3] , and the like. As the (meth) acryloxyalkylsilanes, commercially available products can be used. For example, product numbers “LS-2080”, “LS-2826”, “LS-2827” manufactured by Shin-Etsu Chemical Co., Ltd., “LS-3375”, “LS-3380”, “LS-4548”, “LS-5118”, and the like can be used.

On the other hand, the (meth) acrylate monomer containing fluorine is preferably an alkyl (meth) acrylate having 5 to 16 carbon atoms in which one or more hydrogen atoms are substituted with fluorine. Specifically, 2,2,2 -Trifluoroethyl acrylate [CF ₃ CH ₂ OCOCH═CH ₂ , fluorine content 37% by mass] 2,2,3,3,3-pentafluoropropyl acrylate [CF ₃ CF ₂ CH ₂ OCOCH═CH ₂ , fluorine Content 47 mass%], 2- (perfluorobutyl) ethyl acrylate [CF ₃ (CF ₂ ) ₃ CH ₂ CH ₂ OCOCH═CH ₂ , fluorine content 54 mass%], 3- (perfluorobutyl) -2 -Hydroxypropyl acrylate [CF ₃ (CF ₂ ) ₃ CH ₂ CH (OH) CH ₂ OCOCH═CH ₂ , fluorine content 49% by mass], 2- (perfluorohexyl) ethyl acrylate [CF ₃ (CF ₂ ) ₅ CH ₂ CH ₂ OCOCH═CH ₂ , fluorine content 59 mass%], 3- (perfluorohexyl) -2-hydroxypropyl acrylate [CF ₃ (CF ₂ ) ₅ CH ₂ CH (OH) CH ₂ OCOCH = CH ₂ , fluorine content 55% by mass], 2- (perfluorooctyl) ethyl acrylate [CF ₃ (CF ₂ ) ₇ CH ₂ CH ₂ OCOCH = CH ₂ , fluorine content 62% by mass], 3- (Perfluorooctyl) -2-hydroxypropyl acrylate [CF ₃ (CF ₂ ) ₇ CH ₂ CH (OH) CH ₂ OCOCH═CH ₂ , fluorine content 59 mass%], 2- (perfluorodecyl) ethyl acrylate [ CF ₃ (CF ₂ ) ₉ CH ₂ CH ₂ OCOCH═CH ₂ , fluorine content 65 mass%], 2- (perfluoro-3-methylbutyl) ethyl acrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₂ CH ₂ CH ₂ OCOCH = CH ₂ , fluorine content 57 mass%], 3- (perfluoro-3-methylbutyl) -2-hydroxypropyl acrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₂ CH ₂ CH (OH) CH ₂ OCOCH = CH ₂ , fluorine content 52 mass%], 2- (perfluoro-5-methylhexyl) ethyl acrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₄ CH ₂ CH ₂ OCOCH═CH ₂ , fluorine content 61 mass %], 3- (perfluoro-5-methylhexyl) -2-hydroxypropyl acrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₄ CH ₂ CH (OH) CH ₂ OCOCH = CH ₂ , fluorine content 57 mass %], 2- (perfluoro-7-methyloctyl) ethyl acrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₆ CH ₂ CH ₂ OCOCH═CH ₂ , fluorine content 64 mass], 3- (perfluoro- 7-methyloctyl) -2-hydroxypropyl acrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₆ CH ₂ CH (OH) CH ₂ OCOCH═CH ₂ , fluorine content 60 mass%], 1H, 1H, 3H-tetrafluoropropyl acrylate [CHF ₂ CF ₂ CH ₂ OCOCH = CH ₂ , fluorine content 41% by mass], 1H, 1H, 5H-octafluoropentyl acrylate [CHF ₂ (CF ₂ ) ₃ CH ₂ OCOCH═CH ₂ , fluorine content 53% by mass], 1H, 1H, 7H-dodecafluoroheptyl acrylate [CHF ₂ (CF ₂ ) ₅ CH ₂ OCOCH═CH ₂ , fluorine content 59 mass%], 1H, 1H, 9H-hexadecafluorononyl acrylate [CHF ₂ (CF ₂ ) ₇ CH ₂ OCOCH = CH _2, fluorine content 63 wt%], 1H-1- (trifluoromethyl) trifluoroethyl acrylate _{[(CF 3) 2 CHOCOCH =} CH 2, fluorine content 51 quality %], IH, IH, 3H-hexafluorobutyl acrylate _{[CF 3 CHFCF 2 CH 2 OCOCH} = CH 2, fluorine content 48 wt%, 2,2,2-trifluoroethyl methacrylate [CF ₃ CH ₂ OCOC ( CH ₃ ) = CH ₂ , fluorine content 34 mass%] 2,2,3,3,3-pentafluoropropyl methacrylate [CF ₃ CF ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 44 mass %], 2- (perfluorobutyl) ethyl methacrylate [CF ₃ (CF ₂ ) ₃ CH ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 51 mass%], 3- (perfluorobutyl) -2 -Hydroxypropyl methacrylate [CF ₃ (CF ₂ ) ₃ CH ₂ CH (OH) CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 47 mass%], 2- (perfluorohexyl) ethyl methacrylate [CF ₃ ( CF ₂ ) ₅ CH ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 57 mass%], 3- (perfluorohexyl) -2-hydroxypropyl methacrylate [CF ₃ (CF ₂ ) ₅ CH ₂ CH (OH) CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 53 mass%], 2- (perfluorooctyl) ethyl methacrylate [CF ₃ (CF ₂ ) ₇ CH ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine Content 61 mass%], 3-perfluorooctyl-2-hydroxypropyl methacrylate [CF ₃ (CF ₂ ) ₇ CH ₂ CH (OH) CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 57 mass%] 2- (perfluorodecyl) ethyl methacrylate [CF ₃ (CF ₂ ) ₉ CH ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 63 mass%], 2- (perfluoro-3-methylbutyl) ethyl Methacrylate [(CF ₃ ) ₂ CF (C F ₂ ) ₂ CH ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 55 mass%], 3- (perfluoro-3-methylbutyl) -2-hydroxypropyl methacrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₂ CH ₂ CH (OH) CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 51 mass%], 2- (perfluoro-5-methylhexyl) ethyl methacrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₄ CH ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 59 mass%], 3- (perfluoro-5-methylhexyl) -2-hydroxypropyl methacrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₄ CH ₂ CH (OH) CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 56 mass%], 2- (perfluoro-7-methyloctyl) ethyl methacrylate [(CF ₃ ) ₂ CF (CF _{2) 6 CH 2 CH 2 OCOC} (CH 3) = CH 2, fluorine content 62 wt% 3- (perfluoro-7-methyl-octyl) -2-hydroxypropyl methacrylate _{[(CF 3) 2 CF (} CF 2) 6 CH 2 CH (OH) CH 2 OCOC (CH 3) = CH 2, the fluorine content 59 mass%], 1H, 1H, 3H-tetrafluoropropyl methacrylate [CHF ₂ CF ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 51 mass%], 1H, 1H, 5H-octafluoropentyl methacrylate [ CHF ₂ (CF ₂ ) ₃ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 51 mass%], 1H, 1H, 7H-dodecafluoroheptyl methacrylate [CHF ₂ (CF ₂ ) ₅ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 57 mass%], 1H, 1H, 9H-hexadecafluorononyl methacrylate [CHF ₂ (CF ₂ ) ₇ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 61 mass%] 1H- - (trifluoromethyl) trifluoroethyl methacrylate _{[(CF 3) 2 CHOCOC (} CH 3) = CH 2, fluorine content 48 wt%], 1H, 1H, 3H- hexafluoro-butyl methacrylate [CF ₃ CHFCF ₂ CH ₂ OCOC (CH ₃ ) ═CH ₂ , fluorine content 46% by mass].

  In the coating layer raw material, the ratio of the (meth) acrylate monomer (B) to the total of the (meth) acrylate oligomer (A) and the (meth) acrylate monomer (B) is preferably in the range of 10 to 60% by mass. . If the content of the (meth) acrylate monomer (B) is less than 10% by mass, the UV-cured film may have a tackiness, which may cause abrasion due to friction. Unreacted monomer tends to remain in the film, and bleeding of uncured components becomes a problem.

  The photopolymerization initiator (C) used as the raw material for the coating layer is an action for initiating polymerization of the (meth) acrylate oligomer (A) and the (meth) acrylate monomer (B) described above by being irradiated with ultraviolet rays. Have Examples of the photopolymerization initiator (C) 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, alkyl benzoylbenzoate, bis (4-dialkylaminophenyl) ketone, benzyl, benzylmethyl ketal, etc. Benzyl derivatives of benzoin, benzoin derivatives such as benzoin and benzoin isobutyl ether, benzoin isopropyl ether, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, 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. Is mentioned. These photoinitiators may be used individually by 1 type, and may use 2 or more types together. The blending amount of the photopolymerization initiator (C) in the coating layer raw material is preferably in the range of 0.2 to 5.0 parts by mass with respect to 100 parts by mass in total of the oligomer and monomer.

  In the raw material for the coating layer, a tertiary amine photopolymerization accelerator such as triethylamine or triethanolamine, or a phosphine light such as triphenylphosphine is used to promote the polymerization reaction by the photopolymerization initiator (C). A polymerization accelerator, a thioether photopolymerization accelerator such as thiodiglycol, and the like may be further added to the paint. The addition amount of these photopolymerization accelerators is preferably in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass in total of the oligomer and the monomer.

  The coating layer of the present invention is a coating layer in which at least the coating layer adjacent to the elastic layer contains (meth) acrylate oligomer (A), (meth) acrylate monomer (B) and photopolymerization initiator (C). It consists of an ultraviolet curable resin obtained by curing the layer material by ultraviolet irradiation, but the coating layer other than the coating layer adjacent to the elastic layer is not particularly limited and is the same as the coating layer adjacent to the elastic layer. Or different. In addition to the above (meth) acrylate oligomer (A), (meth) acrylate monomer (B) and photopolymerization initiator (C), the raw material for the coating layer adjacent to the elastic layer is a conductive agent, fine particles, It is preferable to contain a polymerization inhibitor and the like.

  In the conductive roller of the present invention, the coating layer raw material may contain a conductive agent in order to impart conductivity, and the conductive agent can be used for an elastic layer described later. The same thing is mentioned.

  In the conductive roller of the present invention, the coating layer material may further contain fine particles. By including fine particles in the raw material for the coating layer, appropriate fine 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 Urethane acrylate, melamine resin, phenol resin, (meth) acrylic resin, glassy carbon fine particles and silica fine particles are particularly preferred. These fine particles may be used alone or in combination of two or more. In addition, the content of the fine particles is preferably in the range of 0.1 to 100 parts by mass with respect to 100 parts by mass in total of the oligomer and the monomer.

  In the conductive roller of the present invention, the raw material for the coating layer may further contain a polymerization inhibitor. By adding a polymerization inhibitor, thermal polymerization before ultraviolet irradiation can be prevented. Polymerization inhibitors include hydroquinone, hydroquinone monomethyl ether, p-methoxyphenol, 2,4-dimethyl-6-t-butylphenol, 2,6-di-t-butyl-p-cresol, butylhydroxyanisole, 3 -Hydroxythiophenol, α-nitroso-β-naphthol, p-benzoquinone, 2,5-dihydroxy-p-quinone and the like. In addition, the content of the polymerization inhibitor is preferably in the range of 0.001 to 0.2 parts by mass with respect to 100 parts by mass in total of the oligomer and the monomer.

  In the conductive roller of the present invention, the ultraviolet curable resin that forms at least the coating layer adjacent to the elastic layer preferably has a breaking elongation of 50% or more, more preferably 80 to 800%. If the elongation at break of the ultraviolet curable resin is less than 50%, the elongation of the coating layer is impaired, and the durability of the roller may be reduced.

  In the conductive roller of the present invention, the ultraviolet curable resin that forms at least the coating layer adjacent to the elastic layer preferably has a friction coefficient of 0.5 or less, and more preferably 0.1 to 0.5. When the friction coefficient of the ultraviolet curable resin exceeds 0.5, a strong frictional force acts on a contact portion with the toner or other adjacent member, so that the durability of the roller may be lowered.

  Furthermore, in the conductive roller of the present invention, the ultraviolet curable resin that forms at least the coating layer adjacent to the elastic layer preferably has a glass transition point (Tg) of −30 ° C. or higher, and −10 to 80 ° C. More preferably. As a means for keeping the friction coefficient of the ultraviolet curable resin low, it is effective to increase the glass transition point (Tg) of the ultraviolet curable resin. On the other hand, when the glass transition point (Tg) is less than −30 ° C., the surface friction becomes high and the toner tends to deteriorate.

  The shaft member of the conductive roller of the present invention is not particularly limited as long as it has good conductivity. Examples thereof include a metal cylinder and a cylinder made of high-rigidity resin. In addition, when using highly rigid resin for a shaft, 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. The blending amount of the conductive agent is not particularly limited, but is preferably in the range of 5 to 40% by mass, and more preferably in the range of 5 to 20% by mass with respect to the entire highly rigid resin.

  The elastic layer of the conductive roller of the present invention is formed of an elastomer, and may contain other components such as a conductive agent as necessary. Examples of the elastomer used for the elastic layer include polyurethane, silicone rubber, ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene rubber (NBR), natural rubber (NR), styrene-butadiene rubber (SBR), and butadiene rubber (BR). , Isoprene rubber (IR), polynorbornene rubber, butyl rubber (IIR), chloroprene rubber (CR), acrylic rubber, epichlorohydrin rubber (ECO), ethylene-vinyl acetate copolymer (EVA), and mixtures thereof. Among these, polyurethane is 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. Specifically, an elastomer raw material, preferably a urethane raw material foamed by mechanical agitation, is poured into a cylindrical mold in which the shaft member 2 is arranged in advance, and is reacted and cured, whereby the radial direction of the shaft member 2 is reached. A roller body having the elastic layer 3 on the outside can be obtained. Further, the elastic layer of the conductive roller of the present invention is composed of an ultraviolet curable resin formed by ultraviolet curing a raw material containing the (meth) acrylate oligomer or the (meth) acrylate monomer used for the coating layer described above. May be.

  Examples of the conductive agent used for the elastic layer include an ionic conductive agent and an electronic conductive agent. 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 conductive roller of the present invention is prepared by, for example, preparing a coating layer raw material (coating material) containing each component constituting the coating layer and applying it to the outer surface of the roller body formed by forming an elastic layer on the outer periphery of the shaft. Then, it can be produced by irradiating with ultraviolet rays to form a coating layer. Moreover, in the electroconductive roller which has two or more coating film layers, it can produce by repeating the same procedure. In this case, 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 apply | coating the raw material for coating-film layers (coating material) to the outer surface of an elastic layer and a coating-film layer, a spray method, a roll coater method, a dipping method, a die-coating method etc. are mentioned. 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 and coating amounts contained in various raw materials, and the irradiation intensity, the integrated light amount, etc. 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. 2 is a partial cross-sectional view of an example of the image forming apparatus of the present invention. The image forming apparatus in the illustrated example supplies a photosensitive drum 5 that holds an electrostatic latent image, a charging roller 6 that is positioned near (upward in the drawing) of the photosensitive drum 5 and charges the photosensitive drum 5, and toner 7. A toner supply roller 8, a developing roller 9 disposed between the toner supply roller 8 and the photosensitive drum 5, a stratification blade 10 provided in the vicinity of the developing roller 9 (upward in the drawing), and a photosensitive drum 5 is provided with a transfer roller 11 located in the vicinity (downward in the drawing) 5 and a cleaning roller 12 disposed adjacent to the photosensitive drum 5. 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 6 is brought into contact with the photosensitive drum 5 and a voltage is applied between the photosensitive drum 5 and the charging roller 6 to charge the photosensitive drum 5 to a constant potential. Then, an electrostatic latent image is formed on the photosensitive drum 5 by an exposure machine (not shown). Next, the photosensitive drum 5, the toner supply roller 8, and the developing roller 9 rotate in the direction of the arrow in the figure, so that the toner 7 on the toner supply roller 8 is sent to the photosensitive drum 5 through the developing roller 9. It is done. The toner 7 on the developing roller 9 is adjusted to a uniform thin layer by the stratifying blade 10 and rotates while the developing roller 9 and the photosensitive drum 5 are in contact with each other, so that the toner 7 is transferred from the developing roller 9 to the photosensitive drum 5. It adheres to the electrostatic latent image and the latent image becomes visible. The toner 7 attached to the latent image is transferred to a recording medium such as paper by the transfer roller 11, and the toner 7 remaining on the photosensitive drum 5 after the transfer is removed by the cleaning roller 12. Here, in the image forming apparatus of the present invention, for example, at least one of the charging roller 6, the toner supply roller 8, the developing roller 9, the transfer roller 11, and the cleaning roller 12, for example, the elastic layer 3 and the coating layer described above. 4 and the conductive roller 1 having excellent durability can be used to stably form an excellent image.

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

  First, the roller main body which has the elastic layer of the specification common to Examples 1-26 and Comparative Examples 1-6 was produced based on the following prescription.

(Production of roller body)
100 parts by mass of an isocyanate component which is a polyol-modified tolylene diisocyanate having a NCO content of 6.7% prepolymerized with a polyether polyol, 2.0 parts by mass of conductive carbon black, a poly having an average functional group number of 3 and a hydroxyl value of 37.0 mgKOH / g 21 parts by mass of ether polyol, 19 parts by mass of polyether polyol having a hydroxyl value of 388 mgKOH / g and an average number of functional groups of 3 and 5 parts by mass of reactive silicone foam stabilizer (polydimethylsiloxane / polyethylene oxide copolymer) having a hydroxyl value of 34 mgKOH / g Then, 0.3 parts by mass of sodium perchlorate and 0.2 parts by mass of dibutyltin dilaurate were mixed to prepare a polyurethane raw material. This polyurethane raw material was foamed by a mechanical floss method. By casting this foamed polyurethane raw material into a mold on which a metal shaft was set, a roller body having an elastic layer of urethane foam around the shaft was produced. The foaming ratio of the obtained urethane foam was 1.6 times.

<Examples 1-26 and Comparative Examples 1-6>
Next, on the surface of the roller body, a coating layer coating liquid having the formulation shown in Tables 1 to 3 was applied with a roll coater, and UV irradiation was performed at a UV irradiation intensity of 1500 mW / cm ² for 5 seconds. A conductive roller having a UV coating film [thickness: 20 μm] was obtained. For the obtained conductive roller, the roller durability test was evaluated by the following method. In addition, the elastic modulus, elongation at break, glass transition point, and friction coefficient of an ultraviolet curable resin obtained by curing the coating layer coating solution by ultraviolet irradiation were also measured by the following methods. The results are shown in Tables 1-3.

(1) Roller Durability Test After incorporating a conductive roller into the image forming apparatus as a developing roller and printing 5,000 sheets, the degree of roller scraping on the conductive roller was visually judged according to the following criteria.
“○” indicates that no line can be seen on the surface of the roller, but no step can be confirmed even if visible, and “×” indicates that the step can be clearly confirmed on the surface of the roller.

(2) Breaking Elongation and Elastic Modulus of Ultraviolet Curing Resin Evaluation was made by a JIS method plastic film and sheet tensile test method (JIS K 7127-1989). Specifically, the resin coating was UV cured in a glass mold to prepare a resin plate, which was cut into strips having a total length of 20 cm and a width of 1 to 2.5 cm to obtain samples. With respect to this sample, the distance between chucks was 10 cm, and the elongation at break was recorded with a tensile tester [STA-1150 manufactured by Orientec Co., Ltd.]. The elastic modulus was calculated from the stress at 5% elongation of the sample.

(3) Glass transition point (Tg) of UV curable resin
A film having a thickness of 0.5 mm was prepared using the coating layer coating solution, and the temperature was calculated using a temperature variable viscometer.

(4) Friction coefficient of ultraviolet curable resin A three-point average static friction coefficient was measured with a tribometer with a conductive roller fixed horizontally and a felt used for toner sealing. As the friction meter, HEIDON Tribogear Muse TYPE: 941 manufactured by Shinto Kagaku Co., Ltd. was used.

* 1 Urethane acrylate oligomer, Nippon Kayaku Co., Ltd., number of functional groups = 2, weight average molecular weight = 11500.
* 2 Urethane acrylate oligomer, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., number of functional groups = 2, weight average molecular weight = 18000.
* 3 Urethane acrylate oligomer, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., number of functional groups = 2, weight average molecular weight = 10000.
* 4 Urethane acrylate oligomer, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., number of functional groups = 2, weight average molecular weight = 5000.
* 5 Urethane acrylate oligomer, manufactured by Kyoeisha Chemical Co., Ltd., number of functional groups = 2, weight average molecular weight = 4500.
* 6 Urethane acrylate oligomer, Daiichi Kogyo Seiyaku Co., Ltd., functional group number = 3, weight average molecular weight = 5000 or more.
* 7 Polar group-containing acrylate monomer, acryloylmorpholine, manufactured by Shin-Nakamura Chemical Co., Ltd.
* 8 Bulky substituent-containing acrylate monomer, isobornyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd.
* 9 Bulky substituent-containing acrylate monomer, phenoxyethyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd.
* 10 Acrylate monomer, lauryl acrylate, manufactured by Kyoeisha Chemical Co., Ltd.
* 11 Acrylate monomer, diisopropylmethoxyacrylate, manufactured by Kyoeisha Chemical Co., Ltd.
* 12 2-Butyl-2-ethyl-1,3-propanediol diacrylate, manufactured by Kyoeisha Chemical Co., Ltd.
* 13 1,6-hexanediol diacrylate, manufactured by Kyoeisha Chemical Co., Ltd.
* 14 Silicone acrylate, one-end reactive silicone oil, manufactured by Shin-Etsu Silicone Co., Ltd.
* 15 Silicone acrylate, one-end reactive silicone oil, manufactured by Shin-Etsu Silicone Co., Ltd.
* 16 Silicone acrylate, side chain reactive silicone oil, manufactured by Shin-Etsu Silicone Co., Ltd.
* 17 Silicone acrylate, both-end reactive silicone oil, manufactured by Shin-Etsu Silicone Co., Ltd.
* 18 Silicone acrylate, one-end reactive silicone oil, manufactured by Shin-Etsu Silicone Co., Ltd.
* 19 Silicone acrylate, one-end reactive silicone oil, manufactured by Shin-Etsu Silicone Co., Ltd.
* 20 1-hydroxycyclohexyl phenyl ketone, manufactured by Ciba Specialty Chemicals Co., Ltd.

  From Tables 1 to 3, the conductive roller of the example has better durability than the conductive roller of the comparative example by using a coating layer made of an ultraviolet curable resin having an elastic modulus of 100 MPa or less. I understood.

It is sectional drawing of an example of the electroconductive 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 Conductive roller 2 Shaft member 3 Elastic layer 4 Coating layer 5 Photosensitive drum 6 Charging roller 7 Toner 8 Toner supply roller 9 Developing roller 10 Layering blade 11 Transfer roller 12 Cleaning roller

Claims (5)

In a conductive roller comprising a shaft member, an elastic layer disposed on the radially outer side of the shaft member, and one or more coating layers disposed on the radially outer side of the elastic layer,
At least the coating layer adjacent to the elastic layer is cured by irradiating the coating layer material containing (meth) acrylate oligomer (A), (meth) acrylate monomer (B) and photopolymerization initiator (C) with ultraviolet irradiation. An electroconductive roller comprising an ultraviolet curable resin having an elastic modulus of 100 MPa or less.   The conductive roller according to claim 1, wherein the total thickness of the coating layer is 5 μm or more.   The conductive roller according to claim 1, wherein the (meth) acrylate oligomer (A) has 2 to 4 functional groups.   The (meth) acrylate monomer (B) is at least selected from the group consisting of acryloylmorpholine, N, N-diethylaminoethyl methacrylate, isobornyl acrylate, phenoxyethyl acrylate, and (meth) acrylate monomer containing silicon or fluorine The conductive roller according to claim 1, wherein the conductive roller is one type.   An image forming apparatus using the conductive roller according to claim 1.

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