JP2007206442A - Conductive elastic roller and image forming apparatus equipped with same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive elastic roller equipped with an elastic layer having small dependence of dimensions on the environment without increasing production cost. <P>SOLUTION: The conductive elastic roller comprises a shaft member and one or more elastic layers disposed on the radial outside of the shaft member, wherein at least one layer of the elastic layers is made of an ultraviolet curing resin obtained by curing raw material for an elastic layer containing a urethane acrylate oligomer (A), a photopolymerization initiator (B), a conductive agent (C) and an acrylate monomer (D) by ultraviolet irradiation. At least part of the acrylate monomer (D) is an acrylate monomer (E) represented by formula (I), where R is alkyl, cycloalkyl, aryl or aralkyl. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a conductive elastic roller and an image forming apparatus including the conductive elastic roller, and more particularly to a conductive elastic roller having an elastic layer that is suitable as a developing roller, a charging roller, and the like and has a small dimensional environmental dependency. It is.

  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, i.e., a conductive elastic roller, is often used, and the conductive elastic roller is usually provided with a shaft member that is attached by being supported at both ends in the length direction, And one or more elastic layers disposed on the radially outer side of the shaft member.

  For the shaft member of the conductive elastic roller, various resins such as engineering plastics are used in addition to metals such as iron and stainless steel. On the other hand, various thermosetting resins such as a thermosetting urethane resin are used for the elastic layer of the conductive elastic roller, and a resin raw material is injected into a mold having a desired cavity shape and heated. It is manufactured by heat-curing a resin raw material (see Patent Document 1 below).

JP 2004-150610 A

  However, when producing a conductive elastic roller using a thermosetting urethane resin or the like for the elastic layer, it is necessary to heat and cure the resin raw material, which requires a large amount of heat energy, and is also suitable for curing. It took time. In addition, there is a problem that a large amount of equipment costs such as a curing furnace are required for heat curing.

  In contrast, the present inventors examined a conductive elastic roller using an ultraviolet curable resin instead of a thermosetting resin for the elastic layer, but an ultraviolet curable resin using a general acrylate monomer is It has been found that the environmental dependency of dimensions is large. Here, when a roller whose dimension of the elastic layer greatly depends on the environment is used as a developing roller or the like of the image forming apparatus, the outer diameter of the roller greatly changes depending on the use environment, and image defects are likely to occur. Therefore, the elastic layer of the conductive elastic roller needs to have sufficiently small environmental dependency of dimensions.

  Therefore, the object of the present invention is to solve the above-mentioned problems of the prior art, can be manufactured in a short time without requiring a large amount of heat energy, and does not require a large amount of equipment cost. It is an object of the present invention to provide a conductive elastic roller having an elastic layer that is less dependent on the environment. Another object of the present invention is to provide an image forming apparatus that can stably form a good image using such a conductive elastic roller.

  As a result of intensive studies to achieve the above object, the present inventor has cured a raw material composition containing a hydrophobic acrylate monomer having a specific structure together with a urethane acrylate oligomer, a photopolymerization initiator, and a conductive agent, by irradiating it with ultraviolet rays, and is elastic. By forming a layer, conductive elasticity with an elastic layer that can be manufactured in a short time without requiring a large amount of heat energy, does not require a large amount of equipment costs, and has a small dimensional environmental dependency The present inventors have found that a roller can be obtained and have completed the present invention.

［式中、Ｒは、アルキル基、シクロアルキル基、アリール基又はアラルキル基である］で表されるアクリレートモノマー（Ｅ）であることを特徴とする。 That is, the conductive elastic roller of the present invention comprises a shaft member and one or more elastic layers disposed on the outer side in the radial direction of the shaft member,
At least one layer of the elastic layer is an ultraviolet curable type in which a raw material for an elastic layer containing a urethane acrylate oligomer (A), a photopolymerization initiator (B), a conductive agent (C) and an acrylate monomer (D) is cured by ultraviolet irradiation. Made of resin,
At least a part of the acrylate monomer (D) is represented by the following general formula (I):

[Wherein, R is an alkyl group, a cycloalkyl group, an aryl group, or an aralkyl group].

  In the electroconductive elastic roller of the present invention, R in the general formula (I) preferably has 12 to 18 carbon atoms. Moreover, it is particularly preferable that at least a part of the acrylate monomer (D) is at least one selected from the group consisting of isomyristyl acrylate, lauryl acrylate and stearyl acrylate.

  In a preferred example of the conductive elastic roller of the present invention, the conductive agent (C) is an ionic conductive agent.

  In the conductive elastic roller of the present invention, the elastic layer material used for the ultraviolet curable resin is generally selected when the total mass of the urethane acrylate oligomer (A) and the acrylate monomer (D) is 100 parts by mass. The mass of the acrylate monomer (E) represented by the formula (I) is preferably 1 to 90 parts by mass.

  In the conductive elastic roller of the present invention, the raw material for the elastic layer used in the ultraviolet curable resin is the photopolymerization with respect to a total of 100 parts by mass of the urethane acrylate oligomer (A) and the acrylate monomer (D). It is preferable to contain 0.2 to 5.0 parts by mass of the initiator (B) and 0.1 to 5.0 parts by mass of the conductive agent (C).

In another preferred embodiment of the conductive elastic roller of the present invention, the shaft member is a metal shaft or a shaft in which a highly rigid resin base material is disposed outside the metal shaft,
The outer diameter of the metal shaft is 4.0 to 8.0 mm, and the outer diameter of the resin base material is 10 to 25 mm.

  In the conductive elastic roller of the present invention, the elastic layer preferably has an Asker C hardness of 30 to 70 degrees and a thickness of 1 to 3000 μm.

  The conductive elastic roller of the present invention is suitable as a developing roller and a charging roller.

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

  According to the present invention, the elastic layer material containing the urethane acrylate oligomer (A), the photopolymerization initiator (B), and the conductive agent (C), and further containing the hydrophobic acrylate monomer (D) having a specific structure is used as an ultraviolet ray. By curing by irradiation to form at least one elastic layer, it can be manufactured in a short time without requiring a large amount of heat energy, and does not require a large amount of equipment cost, and the environment dependence of dimensions It is possible to provide a conductive elastic roller having an elastic layer having a small diameter. Further, it is possible to provide an image forming apparatus that includes such a conductive elastic roller and can stably form a good image.

<Conductive elastic roller>
Hereinafter, the conductive elastic roller of the present invention will be described in detail with reference to FIG. FIG. 1 is a cross-sectional view of an example of the conductive elastic roller of the present invention. The conductive elastic roller 1 in the illustrated example includes a shaft member 2 that is attached with both ends in the length direction being pivotally supported, and an elastic layer 3 that is disposed on the outer side in the radial direction of the shaft member 2. Although the conductive elastic roller 1 shown in FIG. 1 has only one elastic layer 3, the conductive elastic roller of the present invention may have two or more elastic layers. Although not shown, the conductive elastic roller of the present invention may include a coating layer on the radially outer side of the elastic layer 3.

  In FIG. 1, the shaft member 2 is composed of a metal shaft 2A and a highly rigid resin base material 2B disposed on the outer side in the radial direction of the metal shaft 2A. The shaft member of the conductive elastic roller of the present invention is As long as it has good electrical conductivity, there is no particular limitation, and it may be composed only of the metal shaft 2A, may be composed only of a highly rigid resin base material, or is made of a metal whose interior is hollowed Alternatively, it may be a cylindrical body made of a highly rigid resin. In addition, when using highly rigid resin for the shaft member 2, it is preferable to ensure sufficient electroconductivity by adding and dispersing a conductive agent in the 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.

  Examples of the material of the metal shaft 2A and the metal cylinder include iron, stainless steel, and aluminum. The material of the high-rigidity resin base material 2B includes polyacetal, polyamide 6, polyamide 6 · 6, polyamide 12, polyamide 4 · 6, polyamide 6 · 10, polyamide 6 · 12, polyamide 11, polyamide MXD6, poly Butylene terephthalate, polyphenylene oxide, polyphenylene sulfide, polyethersulfone, polycarbonate, polyimide, polyamideimide, polyetherimide, polysulfone, polyetheretherketone, polyethylene terephthalate, polyarylate, liquid crystal polymer, polytetrafluoroethylene, polypropylene, ABS resin, Examples include polystyrene, polyethylene, melamine resin, phenol resin, and silicone resin. Among these, polyacetal, polyamide 6/6, polyamide MXD6, polyamide 6/12, polybutylene terephthalate, polyphenylene ether, polyphenylene sulfide, and polycarbonate are preferable. These highly rigid resins may be used alone or in combination of two or more.

  When the shaft member is a metal shaft or a shaft having a highly rigid resin base disposed on the outside of the metal shaft, the outer diameter of the metal shaft is preferably in the range of 4.0 to 8.0 mm. Further, when the shaft member is a shaft in which a highly rigid resin base material is disposed outside the metal shaft, the outer diameter of the resin base material is preferably in the range of 10 to 25 mm. In addition, even if the outer diameter of a shaft member is enlarged by using high rigidity resin for the said shaft member, the increase in the mass of a shaft member can be suppressed.

  In the conductive elastic roller of the present invention, at least one layer of the elastic layer is made of an elastic layer raw material containing a urethane acrylate oligomer (A), a photopolymerization initiator (B), a conductive agent (C), and an acrylate monomer (D). It consists of an ultraviolet curable resin obtained by curing by irradiation. In addition, various additives can be mix | blended with this raw material for elastic layers, unless the objective of this invention is impaired.

The urethane acrylate oligomer (A) used for the elastic layer material is a compound having one or more acryloyloxy groups (CH ₂ ═CHCOO—) and a plurality of urethane bonds (—NHCOO—). The number of functional groups and the molecular weight of the urethane acrylate oligomer (A) are not particularly limited. The urethane acrylate oligomer (A) can be produced, for example, by synthesizing a urethane prepolymer from a polyol and a polyisocyanate, and adding an acrylate having a hydroxyl group to the urethane prepolymer.

  The polyol used for the synthesis of the urethane prepolymer is a compound having a plurality of hydroxyl groups (OH groups). Specific examples of the polyol include polyether polyol, polyester polyol, polytetramethylene glycol, polybutadiene polyol, and alkylene oxide modification. Examples include polybutadiene polyol and polyisoprene polyol. The polyether polyol is obtained, for example, by adding an alkylene oxide such as ethylene oxide or propylene oxide to a polyhydric alcohol such as ethylene glycol, propylene glycol, or glycerin. The polyester polyol is, for example, ethylene glycol. , Diethylene glycol, 1,4-butanediol, 1,6-hexanediol, propylene glycol, trimethylolethane, trimethylolpropane and other polyhydric alcohols and adipic acid, glutaric acid, succinic acid, sebacic acid, pimelic acid, suberin It is obtained from a polyvalent carboxylic acid such as an acid. These polyols may be used alone or in a blend of two or more.

  The polyisocyanate is a compound having a plurality of isocyanate groups (NCO groups). Specifically, the polyisocyanate includes tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate (crude MDI), Examples include isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, hexamethylene diisocyanate (HDI), these isocyanurate-modified products, carbodiimide-modified products, and glycol-modified products. These polyisocyanates may be used alone or in a blend of two or more.

  In the synthesis of the urethane prepolymer, it is preferable to use a catalyst for urethanization reaction. Examples of the catalyst for urethanization reaction include dibutyltin dilaurate, dibutyltin diacetate, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin thiocarboxylate, tin octenoate, monobutyltin oxide, etc .; stannous chloride, etc. Inorganic lead compounds; organic lead compounds such as lead octenoate; monoamines such as triethylamine and dimethylcyclohexylamine; diamines such as tetramethylethylenediamine, tetramethylpropanediamine, and tetramethylhexanediamine; pentamethyldiethylenetriamine, pentamethyldipropylene Triamines such as triamine and tetramethylguanidine; triethylenediamine, dimethylpiperazine, methylethylpiperazine, methylmorpholine, dimethyl Cyclic amines such as ruaminoethylmorpholine, dimethylimidazole, pyridine; alcohol amines such as dimethylaminoethanol, dimethylaminoethoxyethanol, trimethylaminoethylethanolamine, methylhydroxyethylpiperazine, hydroxyethylmorpholine; bis (dimethylaminoethyl) Ethers, ether amines such as ethylene glycol bis (dimethyl) aminopropyl ether; organic sulfonic acids such as p-toluenesulfonic acid, methanesulfonic acid and fluorosulfuric acid; inorganic acids such as sulfuric acid, phosphoric acid and perchloric acid; sodium alcoholate Bases such as lithium hydroxide, aluminum alcoholate and sodium hydroxide; titanium compounds such as tetrabutyl titanate, tetraethyl titanate and tetraisopropyl titanate; Smus compounds; quaternary ammonium salts and the like. Of these catalysts, organotin compounds are preferred. These catalysts may be used individually by 1 type, and may be used in combination of 2 or more type. The amount of the catalyst used is preferably in the range of 0.001 to 2.0 parts by mass with respect to 100 parts by mass of the polyol.

The acrylate having a hydroxyl group to be added to the urethane prepolymer is a compound having one or more hydroxyl groups and one or more acryloyloxy groups (CH ₂ ═CHCOO—). The acrylate having a hydroxyl group can be added to the isocyanate group of the urethane prepolymer. Examples of the acrylate having a hydroxyl group include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and pentaerythritol triacrylate. These acrylates having a hydroxyl group may be used alone or in combination of two or more.

  The photopolymerization initiator (B) used for the elastic layer raw material has an action of initiating polymerization of the above-described urethane acrylate oligomer (A) and further an acrylate monomer (D) described later by being irradiated with ultraviolet rays. . Examples of the photopolymerization initiator (B) 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 conductive agent (C) used as the elastic layer material has a function of imparting conductivity to the elastic layer. As this electrically conductive agent (C), what can permeate | transmit an ultraviolet-ray is preferable, It is preferable to use an ionic conductive agent and a transparent electronic conductive agent, and it is especially preferable to use an ionic conductive agent. Since the ionic conductive agent dissolves in the urethane acrylate oligomer (A) and has transparency, when the ionic conductive agent is used as the conductive agent (C), the elastic layer material is applied thickly on the shaft member. However, the ultraviolet rays sufficiently reach the inside of the coating film, and the elastic layer material can be sufficiently cured. Here, as the ionic conductive agent, tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium, hexadecyltrimethylammonium, benzyltrimethylammonium, modified fatty acid dimethylethylammonium and the like perchlorate, chlorate, hydrochloride, bromate 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. In addition, transparent electronic conductive agents include fine particles of metal oxides such as ITO, tin oxide, titanium oxide, and zinc oxide; fine particles of metals such as nickel, copper, silver, and germanium: conductive titanium oxide whiskers, conductive titanium Examples include conductive whiskers such as barium acid whiskers. These electrically conductive agents may be used individually by 1 type, and may use 2 or more types together.

  The acrylate monomer (D) used for the elastic layer material is at least partly the acrylate monomer (E) represented by the general formula (I), and may contain other acrylate monomers (F) as necessary. Good. The acrylate monomer (E) has higher hydrophobicity than a general acrylate monomer and is difficult to absorb moisture. Therefore, the environmental dependence of the dimension of an elastic layer can be reduced by mix | blending the acrylate monomer (E) represented by Formula (I) with the raw material for elastic layers. Further, the acrylate monomer (E) acts as a reactive diluent, that is, it can be cured with ultraviolet rays and can reduce the viscosity of the elastic layer material. This acrylate monomer (E) may be used individually by 1 type, and may be used in combination of 2 or more type.

  R in the general formula (I) is an alkyl group, a cycloalkyl group, an aryl group, or an aralkyl group, and preferably has 12 to 18 carbon atoms. Here, examples of the alkyl group include a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, and the like, which may be linear or branched. Examples of the cycloalkyl group include an octylcyclopentyl group, an octylcyclohexyl group, a decylcyclopentyl group, a decylcyclohexyl group, a dodecylcyclopentyl group, a dodecylcyclohexyl group, and the aryl group includes a hexylphenyl group, an ethylnaphthyl group, and a nonyl group. Examples thereof include a phenyl group, a pentylnaphthyl group, a dodecylphenyl group, and an octylnaphthyl group. Examples of the aralkyl group include a phenylhexyl group, a phenylnonyl group, and a phenyldodecyl group.

  Specific examples of the acrylate monomer (E) of the above formula (I) include lauryl acrylate, isomyristyl acrylate, stearyl acrylate, myristyl acrylate, palmityl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, isoamyl acrylate, Examples thereof include bornyl acrylate and isooctyl acrylate, and among these, isomyristyl acrylate, lauryl acrylate and stearyl acrylate are preferable.

Other acrylate monomers (F) that can be used in combination with the acrylate monomer (E) of the above formula (I) include methoxytriethylene glycol acrylate, glycidyl acrylate, butoxyethyl acrylate, ethoxydiethylene glycol acrylate, methoxydipropylene glycol acrylate, phenoxy Examples include ethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and pentaerythritol triacrylate. These acrylate monomers (F) are also monomers having one or more acryloyloxy groups (CH ₂ ═CHCOO—) and act as reactive diluents, that is, are cured with ultraviolet rays, and the viscosity of the elastic layer raw material is reduced. It can be reduced.

  In the elastic layer raw material, when the total mass of the urethane acrylate oligomer (A) and the acrylate monomer (D) is 100 parts by mass, the mass of the acrylate monomer (E) of the formula (I) is in the range of 1 to 90 parts by mass. It is preferable that it exists in. By setting the ratio of the acrylate monomer (E) in the total amount of the urethane acrylate oligomer (A) and the acrylate monomer (D) to 1% by mass or more (that is, the urethane acrylate oligomer (A) and other acrylate monomers (F) By making the ratio of 99% by mass or less), the environmental dependency of the dimensions of the elastic layer can be reduced, while by making the ratio of the acrylate monomer (E) 90% by mass or less (ie, urethane) By setting the ratio of the acrylate oligomer (A) and the other acrylate monomer (F) to 10% by mass or more, an elastic layer suitable for a conductive elastic roller having low hardness and small compressive residual strain can be obtained.

  Moreover, the compounding quantity of the photoinitiator (B) in the said raw material for elastic layers is 0.2-5.0 mass parts with respect to a total of 100 mass parts of the said urethane acrylate oligomer (A) and the said acrylate monomer (D). The range of is preferable. When the blending amount of the photopolymerization initiator (B) is 0.2 parts by mass or less, the effect of initiating UV curing of the elastic layer raw material is small, whereas when it exceeds 5.0 parts by mass, the effect of initiating UV curing is saturated. Further, physical properties such as compression residual strain are lowered, and the cost of the elastic layer raw material is increased.

  Furthermore, the compounding quantity of the electrically conductive agent (C) in the said raw material for elastic layers is the range of 0.1-5.0 mass parts with respect to a total of 100 mass parts of the said urethane acrylate oligomer (A) and the said acrylate monomer (D). Is preferred. If the blending amount of the conductive agent (C) is less than 0.1 parts by mass, the conductivity of the elastic layer may be low and desired conductivity may not be imparted to the conductive elastic roller. On the other hand, if it exceeds 5.0 parts by mass, the elastic layer In some cases, the electrical conductivity of the film does not increase, and physical properties such as compressive residual strain decrease and a good image cannot be obtained.

  Moreover, you may add 0.001-0.2 mass part of polymerization inhibitors with respect to the said raw material for elastic layers further with respect to a total of 100 mass parts of the said urethane acrylate oligomer (A) and the said acrylate monomer (D). 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.

  The elastic layer preferably has an Asker C hardness of 30 to 70 degrees. Here, the Asker C hardness is a value when a flat portion of a cylindrical sample having a height of 12.7 mm and a diameter of 29 mm is measured. If the Asker C hardness is 30 degrees or more, sufficient hardness can be secured as a conductive elastic roller such as a developing roller. On the other hand, if the Asker C hardness is 70 degrees or less, the low melting point toner is sufficiently aggregated and fused. Can be prevented.

  The elastic layer preferably has a thickness of 1 to 3000 μm. If the thickness of the elastic layer is 1 μm or more, the conductive elastic roller has sufficient elasticity and the damage to the toner is sufficiently small. Is sufficiently reached, the raw material for the elastic layer can be surely UV-cured, and the amount of the expensive UV-curing resin raw material can be reduced.

The elastic layer is not particularly limited, but preferably has a compression residual strain (compression set) of 5% or less. Here, the compressive residual strain can be measured in accordance with JIS K 6262 (1997). Specifically, a cylindrical sample having a height of 12.7 mm and a diameter of 29 mm is subjected to a prescribed heat treatment condition (22 at 70 ° C.). Time), the sample can be determined by compressing it in the height direction by 25%. The elastic layer preferably has a volume resistivity of 10 ⁴ to 10 ¹⁰ Ωcm. Furthermore, the conductive elastic roller of the present invention preferably has a roller resistance of 10 ⁴ to 10 ¹⁰ Ω at an applied voltage of 100V. Here, the resistance value is obtained from a current value at that time by applying a voltage of 100 V between the shaft and the counter electrode by pressing the outer peripheral surface of the conductive elastic roller to a flat plate or a cylindrical counter electrode with a predetermined pressure. be able to.

  The conductive elastic roller of the present invention can be produced by applying the elastic layer raw material to the outer surface of the shaft member and then irradiating it with ultraviolet rays. Therefore, the conductive elastic roller of the present invention does not require a large amount of heat energy for the production of the elastic layer, and can produce the elastic layer in a short time. Moreover, since a curing furnace or the like is not required for forming the elastic layer, a large amount of equipment costs are not required. Examples of the method for applying the elastic layer raw material to the outer surface of the shaft member include a spray method, a roll coater method, a dipping method, and a die coating method. 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, and the irradiation intensity and the integrated light amount may be adjusted as appropriate.

  The conductive elastic 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. Particularly suitable as a developing roller and a charging roller.

<Image forming apparatus>
The image forming apparatus of the present invention includes the above-described conductive elastic roller, and preferably includes at least one of a developing roller and a charging roller. The image forming apparatus of the present invention is not particularly limited except that the conductive elastic 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 FIG. 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 4 holding an electrostatic latent image, a charging roller 5 that is positioned near (upward in the drawing) of the photosensitive drum 4 and charges the photosensitive drum 4, and toner 6. A toner supply roller 7, a developing roller 8 disposed between the toner supply roller 7 and the photosensitive drum 4, a developing blade 9 provided in the vicinity of the developing roller 8 (upward in the drawing), and a photosensitive drum. 4 is provided with a transfer roller 10 located in the vicinity (downward in the drawing) 4 and a cleaning roller 11 disposed adjacent to the photosensitive drum 4. 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 illustrated image forming apparatus, the charging roller 5 is brought into contact with the photosensitive drum 4 and a voltage is applied between the photosensitive drum 4 and the charging roller 5 to charge the photosensitive drum 4 to a constant potential. Then, an electrostatic latent image is formed on the photosensitive drum 4 by an exposure machine (not shown). Next, the photosensitive drum 4, the toner supply roller 7, and the developing roller 8 rotate in the direction of the arrow in the drawing, so that the toner 6 on the toner supply roller 7 is sent to the photosensitive drum 4 through the developing roller 8. It is done. The toner 6 on the developing roller 8 is adjusted to a uniform thin layer by the developing blade 9 and rotates while the developing roller 8 and the photosensitive drum 4 are in contact with each other, so that the toner 6 is transferred from the developing roller 8 to the photosensitive drum 4. It adheres to the electrostatic latent image and the latent image becomes visible. The toner 6 adhered to the latent image is transferred to a recording medium such as paper by the transfer roller 10, and the toner 6 remaining on the photosensitive drum 4 after the transfer is removed by the cleaning roller 11. Here, in the image forming apparatus of the present invention, at least one of the charging roller 5, the toner supply roller 7, the developing roller 8, the transfer roller 10 and the cleaning roller 11, preferably at least the charging roller 5 and the developing roller 8. On the other hand, it is possible to stably form an excellent image by using the above-described conductive elastic roller of the present invention.

  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
Urethane acrylate oligomer “UA-334PZ [made by Shin-Nakamura Chemical Co., Ltd.]” 70.0 parts by mass, acrylate monomer “Light acrylate IM-A [Isomyristyl acrylate (CH ₂ ═CHCOOC ₁₄ H ₂₉ ), manufactured by Kyoeisha Chemical Co., Ltd. ] "30.0 parts by mass, photopolymerization initiator" Irgacure 184D [Ciba Specialty Chemicals Co., Ltd.] "0.5 parts by mass, ionic conductive agent" MP-100 [Akishima Chemical Industry Co., Ltd.] "2.0 parts by mass Was stirred and mixed for 1 hour at a liquid temperature of 70 ° C. and 60 rpm, and the liquid mixture was filtered to obtain a UV curable resin raw material.

The above UV curable resin raw material is poured into a mold having a cavity with a depth of 12.7 mm and an inner diameter of 29 mm, covered with a quartz glass plate, and then irradiated with UV at a UV irradiation intensity of 700 mW / cm ² for 10 seconds to measure cylindrical physical properties. A UV curable resin sample was obtained. This sample had an Asker C hardness (manufactured by Kobunshi Keiki Co., Ltd.) of 45 degrees in the plane portion.

  Further, a sheet sample of 2.0 mm was prepared by sandwiching the UV curable resin raw material between two quartz glass plates provided with a 2.0 mm spacer. If necessary, the sheet sample can be easily peeled by sandwiching the PTFE sheet between the quartz glass on the side opposite to the UV irradiation surface and the UV curable resin. The dimensional change due to the environmental conditions of the sample thus obtained was measured. The thickness (A) after standing for 2 days under the environmental conditions (LL conditions) of 12 ° C. and 10% RH and 32.5 ° C., 85% RH The dimensional change (BA) with respect to the thickness (B) after being left for 2 days under the environmental conditions (HH conditions) was 30 μm.

Next, the above UV curable resin raw material is applied to a conductive roller base material made of polybutylene terephthalate (PBT) resin having an outer diameter of 17.0 mm into which a metal shaft having an outer diameter of 6.0 mm is inserted, with a thickness of 1500 μm using a die coater. The UV curable resin raw material was cured by spot UV irradiation. The UV-cured resin elastic layer-formed roller thus formed was further irradiated with UV at a UV irradiation intensity of 700 mW / cm ² for 5 seconds while rotating in a nitrogen atmosphere.

  On the surface of the roller with an elastic layer made of UV curable resin thus obtained, a UV curable resin material containing fine particles having hardness higher than that of the elastic layer is applied with a roll coater, and irradiated with UV to form a UV coating on the surface. A low hardness UV resin roller having an outer diameter of 20.0 mm was obtained. When the dimensional change due to the environmental conditions of this roller was measured, the outer diameter (C) after standing for 2 days under the environmental conditions (LL conditions) of 12 ° C. and 10% RH and the environmental conditions of 32.5 ° C. and 85% RH (HH The dimensional change (DC) with respect to the outer diameter (D) after being allowed to stand for 2 days was 57 μm.

  Further, another roller produced as described above is incorporated in the electrophotographic apparatus as a developing roller, and is 20 ° C., 50% RH (NN condition), 12 ° C., 10% RH (LL condition), 32.5 ° C., 85% RH (HH condition). ) And left for 2 days, and after printing a gray image, a good image could be obtained under all conditions.

(Example 2)
Urethane acrylate oligomer “UA-334PZ [manufactured by Shin-Nakamura Chemical Co., Ltd.]” 60.0 parts by mass, acrylate monomer “light acrylate IM-A [manufactured by Kyoeisha Chemical Co., Ltd.]” 40.0 parts by mass, photopolymerization initiator “Irgacure 184D [manufactured by Ciba Specialty Chemicals Co., Ltd.] “0.5 parts by mass and ionic conductive agent“ MP-100 [manufactured by Akishima Chemical Co., Ltd.] ”2.0 parts by mass with a stirrer at a liquid temperature of 70 ° C. and 60 rotations The mixture was stirred and mixed at 1 min for 1 hour, and the mixture was filtered to obtain a UV curable resin raw material.

The above UV curable resin raw material is poured into a mold having a cavity with a depth of 12.7 mm and an inner diameter of 29 mm, covered with a quartz glass plate, and then irradiated with UV at a UV irradiation intensity of 700 mW / cm ² for 10 seconds to measure cylindrical physical properties. A UV curable resin sample was obtained. This sample had an Asker C hardness (manufactured by Kobunshi Keiki Co., Ltd.) of the flat portion of 40 degrees.

  Further, a sheet sample of 2.0 mm was prepared by sandwiching the UV curable resin raw material between two quartz glass plates provided with a 2.0 mm spacer. If necessary, the sheet sample can be easily peeled by sandwiching the PTFE sheet between the quartz glass on the side opposite to the UV irradiation surface and the UV curable resin. The dimensional change due to the environmental conditions of the sample thus obtained was measured. The thickness (A) after standing for 2 days under the environmental conditions (LL conditions) of 12 ° C. and 10% RH and 32.5 ° C., 85% RH The dimensional change (B-A) with respect to the thickness (B) after being allowed to stand for 2 days under the environmental conditions (HH conditions) was 26 μm.

Next, the above UV curable resin raw material is applied to a PBT resin conductive roller base material having an outer diameter of 17.0 mm inserted with a metal shaft having an outer diameter of 6.0 mm with a die coater at a thickness of 1500 μm, and is applied by spot UV irradiation while being applied. The UV curable resin raw material was cured. The UV-cured resin elastic layer-formed roller thus formed was further irradiated with UV at a UV irradiation intensity of 700 mW / cm ² for 5 seconds while rotating in a nitrogen atmosphere.

  On the surface of the roller with an elastic layer made of UV curable resin thus obtained, a UV curable resin material containing fine particles having hardness higher than that of the elastic layer is applied with a roll coater, and irradiated with UV to form a UV coating on the surface. A low hardness UV resin roller having an outer diameter of 20.0 mm was obtained. When the dimensional change due to the environmental conditions of this roller was measured, the outer diameter (C) after standing for 2 days under the environmental conditions (LL conditions) of 12 ° C. and 10% RH and the environmental conditions of 32.5 ° C. and 85% RH (HH The dimensional change (DC) with respect to the outer diameter (D) after being allowed to stand for 2 days was 53 μm.

  Further, another roller produced as described above is incorporated in the electrophotographic apparatus as a developing roller, and is 20 ° C., 50% RH (NN condition), 12 ° C., 10% RH (LL condition), 32.5 ° C., 85% RH (HH condition). ) And left for 2 days, and after printing a gray image, a good image could be obtained under all conditions.

(Example 3)
Urethane acrylate oligomer “UA-334PZ [manufactured by Shin-Nakamura Chemical Co., Ltd.]” 70.0 parts by mass, acrylate monomer “light acrylate LA [lauryl acrylate (CH ₂ ═CHCOOC ₁₂ H ₂₅ ), manufactured by Kyoeisha Chemical Co., Ltd.] "30.0 parts by mass, photopolymerization initiator" Irgacure 184D [Ciba Specialty Chemicals Co., Ltd.] "0.5 parts by mass, ionic conductive agent" MP-100 [Akishima Chemical Co., Ltd.] "2.0 parts by mass With a stirrer, the mixture was stirred and mixed for 1 hour at a liquid temperature of 70 ° C. and 60 rpm, and the mixed liquid was filtered to obtain a UV curable resin material.

The above UV curable resin raw material is poured into a mold having a cavity with a depth of 12.7 mm and an inner diameter of 29 mm, covered with a quartz glass plate, and then irradiated with UV at a UV irradiation intensity of 700 mW / cm ² for 10 seconds to measure cylindrical physical properties. A UV curable resin sample was obtained. This sample had an Asker C hardness (manufactured by Kobunshi Keiki Co., Ltd.) of 36 degrees in the plane portion.

  Further, a sheet sample of 2.0 mm was prepared by sandwiching the UV curable resin raw material between two quartz glass plates provided with a 2.0 mm spacer. If necessary, the sheet sample can be easily peeled by sandwiching the PTFE sheet between the quartz glass on the side opposite to the UV irradiation surface and the UV curable resin. The dimensional change due to the environmental conditions of the sample thus obtained was measured. The thickness (A) after standing for 2 days under the environmental conditions (LL conditions) of 12 ° C. and 10% RH and 32.5 ° C., 85% RH The dimensional change (B-A) from the thickness (B) after standing for 2 days under the environmental conditions (HH conditions) was 33 μm.

Next, the above UV curable resin raw material is applied to a PBT resin conductive roller base material having an outer diameter of 17.0 mm inserted with a metal shaft having an outer diameter of 6.0 mm with a die coater at a thickness of 1500 μm, and is applied by spot UV irradiation while being applied. The UV curable resin raw material was cured. The UV-cured resin elastic layer-formed roller thus formed was further irradiated with UV at a UV irradiation intensity of 700 mW / cm ² for 5 seconds while rotating in a nitrogen atmosphere.

  On the surface of the roller with an elastic layer made of UV curable resin thus obtained, a UV curable resin material containing fine particles having hardness higher than that of the elastic layer is applied with a roll coater, and irradiated with UV to form a UV coating on the surface. A low hardness UV resin roller having an outer diameter of 20.0 mm was obtained. When the dimensional change due to the environmental conditions of this roller was measured, the outer diameter (C) after standing for 2 days under the environmental conditions (LL conditions) of 12 ° C. and 10% RH and the environmental conditions of 32.5 ° C. and 85% RH (HH The dimensional change (DC) with respect to the outer diameter (D) after being allowed to stand for 2 days was 59 μm.

  Further, another roller produced as described above is incorporated in the electrophotographic apparatus as a developing roller, and is 20 ° C., 50% RH (NN condition), 12 ° C., 10% RH (LL condition), 32.5 ° C., 85% RH (HH condition). ) And left for 2 days, and after printing a gray image, a good image could be obtained under all conditions.

Example 4
Urethane acrylate oligomer “UA-334PZ [Shin Nakamura Chemical Co., Ltd.]” 70.0 parts by mass, acrylate monomer “Light acrylate IM-A [Kyoeisha Chemical Co., Ltd.]” 15.0 parts by mass, acrylate monomer “Light acrylate S-” A [stearyl acrylate (CH ₂ = CHCOOC ₁₈ H ₃₇ ), manufactured by Kyoeisha Chemical Co., Ltd.] “15.0 parts by mass, photopolymerization initiator“ Irgacure 184D [manufactured by Ciba Specialty Chemicals Co., Ltd.] ”0.5 parts by mass, 2.0 parts by mass of ionic conductive agent “MP-100 [Akishima Chemical Industry Co., Ltd.]” was stirred and mixed with a stirrer at a liquid temperature of 70 ° C. and 60 rpm for 1 hour. A cured resin raw material was obtained.

The above UV curable resin raw material is poured into a mold having a cavity with a depth of 12.7 mm and an inner diameter of 29 mm, covered with a quartz glass plate, and then irradiated with UV at a UV irradiation intensity of 700 mW / cm ² for 10 seconds to measure cylindrical physical properties. A UV curable resin sample was obtained. This sample had an Asker C hardness [manufactured by Kobunshi Keiki Co., Ltd.] of 48 degrees in the plane portion.

  Further, a sheet sample of 2.0 mm was prepared by sandwiching the UV curable resin raw material between two quartz glass plates provided with a 2.0 mm spacer. If necessary, the sheet sample can be easily peeled by sandwiching the PTFE sheet between the quartz glass on the side opposite to the UV irradiation surface and the UV curable resin. The dimensional change due to the environmental conditions of the sample thus obtained was measured. The thickness (A) after standing for 2 days under the environmental conditions (LL conditions) of 12 ° C. and 10% RH and 32.5 ° C., 85% RH The dimensional change (BA) with respect to the thickness (B) after being left for 2 days under the environmental conditions (HH conditions) was 29 μm.

Next, the above UV curable resin raw material is applied to a PBT resin conductive roller base material having an outer diameter of 17.0 mm inserted with a metal shaft having an outer diameter of 6.0 mm with a die coater at a thickness of 1500 μm, and is applied by spot UV irradiation while being applied. The UV curable resin raw material was cured. The UV-cured resin elastic layer-formed roller thus formed was further irradiated with UV at a UV irradiation intensity of 700 mW / cm ² for 5 seconds while rotating in a nitrogen atmosphere.

  On the surface of the roller with an elastic layer made of UV curable resin thus obtained, a UV curable resin material containing fine particles having hardness higher than that of the elastic layer is applied with a roll coater, and irradiated with UV to form a UV coating on the surface. A low hardness UV resin roller having an outer diameter of 20.0 mm was obtained. When the dimensional change due to the environmental conditions of this roller was measured, the outer diameter (C) after standing for 2 days under the environmental conditions (LL conditions) of 12 ° C. and 10% RH and the environmental conditions of 32.5 ° C. and 85% RH (HH The dimensional change (DC) with respect to the outer diameter (D) after being allowed to stand for 2 days was 56 μm.

  Further, another roller produced as described above is incorporated in the electrophotographic apparatus as a developing roller, and is 20 ° C., 50% RH (NN condition), 12 ° C., 10% RH (LL condition), 32.5 ° C., 85% RH (HH condition). ) And left for 2 days, and after printing a gray image, a good image could be obtained under all conditions.

(Comparative Example 1)
Urethane acrylate oligomer “UA-334PZ [manufactured by Shin-Nakamura Chemical Co., Ltd.]” 70.0 parts by mass, acrylate monomer “light acrylate MTG-A [methoxy-triethylene glycol acrylate {CH ₂ ═CHCOO— (CH ₂ CH ₂ O) ₃ -CH ₃ }, manufactured by Kyoeisha Chemical Co., Ltd.] “30.0 parts by mass, photopolymerization initiator“ Irgacure 184D [manufactured by Ciba Specialty Chemicals Co., Ltd.] ”, 0.5 parts by mass, ionic conductive agent“ MP-100 [ Akishima Chemical Co., Ltd.] ”2.0 parts by mass was stirred and mixed with a stirrer at a liquid temperature of 70 ° C. and 60 rpm for 1 hour, and the mixed solution was filtered to obtain a UV curable resin raw material.

The above UV curable resin raw material is poured into a mold having a cavity with a depth of 12.7 mm and an inner diameter of 29 mm, covered with a quartz glass plate, and then irradiated with UV at a UV irradiation intensity of 700 mW / cm ² for 10 seconds to measure cylindrical physical properties. A UV curable resin sample was obtained. This sample had an Asker C hardness (manufactured by Kobunshi Keiki Co., Ltd.) of 45 degrees in the plane portion.

  Further, a sheet sample of 2.0 mm was prepared by sandwiching the UV curable resin raw material between two quartz glass plates provided with a 2.0 mm spacer. If necessary, the sheet sample can be easily peeled by sandwiching the PTFE sheet between the quartz glass on the side opposite to the UV irradiation surface and the UV curable resin. The dimensional change due to the environmental conditions of the sample thus obtained was measured. The thickness (A) after standing for 2 days under the environmental conditions (LL conditions) of 12 ° C. and 10% RH and 32.5 ° C., 85% RH The dimensional change (B-A) with respect to the thickness (B) after standing for 2 days under the environmental conditions (HH conditions) was 41 μm.

Next, the above UV curable resin raw material is applied to a PBT resin conductive roller base material having an outer diameter of 17.0 mm inserted with a metal shaft having an outer diameter of 6.0 mm with a die coater at a thickness of 1500 μm, and is applied by spot UV irradiation while being applied. The UV curable resin raw material was cured. The UV-cured resin elastic layer-formed roller thus formed was further irradiated with UV at a UV irradiation intensity of 700 mW / cm ² for 5 seconds while rotating in a nitrogen atmosphere.

  On the surface of the roller with an elastic layer made of UV curable resin thus obtained, a UV curable resin material containing fine particles having hardness higher than that of the elastic layer is applied with a roll coater, and irradiated with UV to form a UV coating on the surface. A low hardness UV resin roller having an outer diameter of 20.0 mm was obtained. When the dimensional change due to the environmental conditions of this roller was measured, the outer diameter (C) after standing for 2 days under the environmental conditions (LL conditions) of 12 ° C. and 10% RH and the environmental conditions of 32.5 ° C. and 85% RH (HH The dimensional change (DC) with respect to the outer diameter (D) after being allowed to stand for 2 days was 78 μm.

  Further, another roller produced as described above is incorporated into the electrophotographic apparatus as a developing roller, and is 20 ° C., 50% RH (NN condition), 12 ° C., 10% RH (LL condition), 32.5 ° C., 85% RH (HH condition). ), And after printing for 2 days, a gray image was printed. A good image was obtained under the NN and LL conditions, but a streak-like image defect occurred under the HH condition. Further, when the surface of the developing roller was observed, a pressure contact mark by the developing blade was confirmed.

(Comparative Example 2)
Urethane acrylate oligomer “UA-334PZ [manufactured by Shin-Nakamura Chemical Co., Ltd.]” 60.0 parts by mass, acrylate monomer “light acrylate MTG-A [manufactured by Kyoeisha Chemical Co., Ltd.]” 40.0 parts by mass, photopolymerization initiator “Irgacure 184D [Ciba Specialty Chemicals Co., Ltd.] “0.5 parts by mass and ionic conductive agent“ MP-100 [Akishima Chemical Co., Ltd.] ”2.0 parts by mass with a stirrer at a liquid temperature of 70 ° C. and 60 rotations The mixture was stirred and mixed at 1 min for 1 hour, and the mixture was filtered to obtain a UV curable resin raw material.

The above UV curable resin raw material is poured into a mold having a cavity with a depth of 12.7 mm and an inner diameter of 29 mm, covered with a quartz glass plate, and then irradiated with UV at a UV irradiation intensity of 700 mW / cm ² for 10 seconds to measure cylindrical physical properties. A UV curable resin sample was obtained. This sample had an Asker C hardness (manufactured by Kobunshi Keiki Co., Ltd.) of 42 degrees in the plane portion.

  Further, a sheet sample of 2.0 mm was prepared by sandwiching the UV curable resin raw material between two quartz glass plates provided with a 2.0 mm spacer. If necessary, the sheet sample can be easily peeled by sandwiching the PTFE sheet between the quartz glass on the side opposite to the UV irradiation surface and the UV curable resin. The dimensional change due to the environmental conditions of the sample thus obtained was measured. The thickness (A) after standing for 2 days under the environmental conditions (LL conditions) of 12 ° C. and 10% RH and 32.5 ° C., 85% RH The dimensional change (B-A) with the thickness (B) after being allowed to stand for 2 days under the environmental conditions (HH conditions) was 48 μm.

Next, the above UV curable resin raw material is applied to a PBT resin conductive roller base material having an outer diameter of 17.0 mm inserted with a metal shaft having an outer diameter of 6.0 mm with a die coater at a thickness of 1500 μm, and is applied by spot UV irradiation while being applied. The UV curable resin raw material was cured. The UV-cured resin elastic layer-formed roller thus formed was further irradiated with UV at a UV irradiation intensity of 700 mW / cm ² for 5 seconds while rotating in a nitrogen atmosphere.

  On the surface of the roller with an elastic layer made of UV curable resin thus obtained, a UV curable resin material containing fine particles having hardness higher than that of the elastic layer is applied with a roll coater, and irradiated with UV to form a UV coating on the surface. A low hardness UV resin roller having an outer diameter of 20.0 mm was obtained. When the dimensional change due to the environmental conditions of this roller was measured, the outer diameter (C) after standing for 2 days under the environmental conditions (LL conditions) of 12 ° C. and 10% RH and the environmental conditions of 32.5 ° C. and 85% RH (HH The dimensional change (DC) with respect to the outer diameter (D) after being allowed to stand for 2 days was 82 μm.

  Further, another roller produced as described above is incorporated in the electrophotographic apparatus as a developing roller, and is 20 ° C., 50% RH (NN condition), 12 ° C., 10% RH (LL condition), 32.5 ° C., 85% RH (HH condition). ), And after printing for 2 days, a gray image was printed. A good image was obtained under the NN and LL conditions, but a streak-like image defect occurred under the HH condition. Further, when the surface of the developing roller was observed, a pressure contact mark by the developing blade was confirmed.

  From Examples 1 to 4, an elastic material containing a urethane acrylate oligomer (A), a photopolymerization initiator (B), and a conductive agent (C), and further containing an acrylate monomer (D) represented by the above general formula (I) The conductive elastic roller provided with an elastic layer made of an ultraviolet curable resin obtained by curing the layer raw material by ultraviolet irradiation has a small environmental dependency on the dimensions of the elastic layer, and the total of the NN, LL, and HH conditions. It can be seen that a good image can be formed under all conditions.

  On the other hand, from the results of Comparative Examples 1 and 2, when an acrylate monomer other than the acrylate monomer represented by the above general formula (I) is used, the environmental dependency of the dimensions of the elastic layer becomes remarkably high, resulting in an image failure under HH conditions. Can be seen.

It is sectional drawing of an example of the electroconductive elastic 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 elastic roller 2 Shaft member 2A Metal shaft 2B High rigid resin base material 3 Elastic layer 4 Photosensitive drum 5 Charging roller 6 Toner 7 Toner supply roller 8 Developing roller 9 Developing blade 10 Transfer roller 11 Cleaning roller

Claims (11)

In a conductive elastic roller comprising a shaft member and one or more elastic layers disposed radially outside the shaft member,
At least one layer of the elastic layer is an ultraviolet curable type in which a raw material for an elastic layer containing a urethane acrylate oligomer (A), a photopolymerization initiator (B), a conductive agent (C), and an acrylate monomer (D) is cured by ultraviolet irradiation. Made of resin,
At least a part of the acrylate monomer (D) is represented by the following general formula (I):

A conductive elastic roller, wherein the conductive elastic roller is an acrylate monomer (E) represented by the formula: wherein R is an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group.   The conductive elastic roller according to claim 1, wherein R in the general formula (I) has 12 to 18 carbon atoms.   2. The conductive elastic roller according to claim 1, wherein at least a part of the acrylate monomer (D) is at least one selected from the group consisting of isomyristyl acrylate, lauryl acrylate, and stearyl acrylate.   The conductive elastic roller according to claim 1, wherein the conductive agent (C) is an ionic conductive agent.   The elastic layer material used for the ultraviolet curable resin is an acrylate represented by the general formula (I) when the total mass of the urethane acrylate oligomer (A) and the acrylate monomer (D) is 100 parts by mass. 2. The conductive elastic roller according to claim 1, wherein the mass of the monomer (E) is in the range of 1 to 90 parts by mass.   The elastic layer material used for the ultraviolet curable resin is 0.2 to 5.0 of the photopolymerization initiator (B) with respect to a total of 100 parts by mass of the urethane acrylate oligomer (A) and the acrylate monomer (D). 2. The conductive elastic roller according to claim 1, wherein the conductive elastic roller contains 0.1 to 5.0 parts by mass of the conductive agent (C).   The conductive elastic roller according to claim 1, wherein the elastic layer has an Asker C hardness of 30 to 70 degrees. The shaft member is a metal shaft or a shaft in which a highly rigid resin base material is disposed outside the metal shaft;
2. The conductive elastic roller according to claim 1, wherein an outer diameter of the metal shaft is 4.0 to 8.0 mm and an outer diameter of the resin base material is 10 to 25 mm.   The conductive elastic roller according to claim 1, wherein the elastic layer has a thickness of 1 to 3000 μm.   The conductive elastic roller according to claim 1, wherein the conductive elastic roller is a developing roller or a charging roller.   An image forming apparatus using the conductive elastic roller according to claim 1.

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