JP2008058622A - Conductive roller and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive roller that even if use environment, installation environment or the like changes, can prevent a body brought into contact from being soiled and enables a high quality image to be formed as required, and to provide an image forming apparatus that has this conductive roller and is not affected by use environment, installation environment or the like. <P>SOLUTION: The conductive roller 1 includes a conductive elastic layer 3 formed on the outer circumferential face of a shaft body 2, and a coat layer 4 formed on the outer circumferential face of the conductive elastic layer 3. The coat layer is formed by hardening a composition containing 100 mass parts of polyurethane adjustment constituent, 1 to 10 mass parts of silicone graft acrylic resin, and 1 to 10 mass parts of silane coupling agent having an amino group. The image forming apparatus has this conductive roller 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a conductive roller and an image forming apparatus. More specifically, even if the use environment or the installation environment changes, contamination of a contacted body can be suppressed and a high-quality image can be formed. The present invention relates to a conductive roller that can be used, and an image forming apparatus including the conductive roller.

  Various types of image forming apparatuses using an electrophotographic system are employed in laser printers, copiers, video printers, facsimiles, and complex machines of these. An image forming apparatus using an electrophotographic system includes a conductive elastic layer (hereinafter sometimes referred to as a conductive elastic layer) formed on an outer peripheral surface of a shaft body. Conductive rollers such as a roller, a developing roller, a transfer roller, and a conveying roller are provided. These conductive rollers contribute to the image forming apparatus forming a high-quality image by carrying the developer as desired or by conveying a recording medium such as recording paper as desired. .

  In general, such a conductive roller has a conductive elastic layer formed of a silicone rubber or a silicone resin that is excellent in chemical stability, heat resistance, cold resistance, weather resistance, oil resistance, and the like. When the conductive elastic layer is formed of silicone rubber or the like, an image is formed by a phenomenon that the developer adheres to the surface of the contacted member that contacts or presses the conductive roller (referred to as filming phenomenon). It is possible to effectively prevent the quality of the product from deteriorating. However, since silicone rubber is usually inferior in abrasion resistance, a high-quality image cannot be formed over a long period of time, and silicone rubber components and / or additives are gradually deposited on the surface of the conductive elastic layer. As a result, the contacted body that contacts or presses against the conductive roller may be contaminated. Therefore, a coating layer containing a rubber component or a resin component other than silicone rubber such as polyurethane or silicone resin may be provided on the outer peripheral surface of the conductive elastic layer in the conductive roller.

  As a conductive roller in which a coating layer is provided on the surface of a conductive elastic layer, for example, Patent Document 1 discloses a shaft body, a base layer formed on the outer peripheral surface of the shaft body, and an outer periphery of the base layer. And a base layer formed using a silicone rubber, the surface layer comprising (A) a urethane raw material, (B) a low molecular weight silicone graft acrylic resin, and (C) “Development roll characterized in that it is formed using a conductive composition containing a conductive agent” is described.

  However, this developing roll can prevent the contacted body from being contaminated to some extent. However, recent image forming apparatuses have a long life, and further improvement in the anti-contamination property for the contacted body is desired. ing.

  Further, a conductive roller disposed in a recent image forming apparatus is required not to deteriorate image quality even if the use environment or installation environment of the image forming apparatus changes.

JP 2004-295095 A

  The present invention provides a conductive roller that can prevent contamination of an abutted object and can form a high-quality image in a desired manner even when the use environment or installation environment changes. Another object of the present invention is to provide an image forming apparatus provided with the conductive roller, which is not affected by the use environment or the installation environment.

As means for solving the problems,
Claim 1 comprises a conductive elastic layer formed on the outer peripheral surface of the shaft body and a coat layer formed on the outer peripheral surface of the conductive elastic layer, and the coat layer comprises 100 parts by mass of a polyurethane preparation component And 1-10 parts by mass of a silicone-grafted acrylic resin, and 1-10 parts by mass of a composition containing a silane coupling agent having an amino group.
The conductive roller according to claim 1, wherein the coating layer has a total concentration of extracted components of 100 ppm or less when xylene is used as a solvent and extracted using a Soxhlet extractor for 6 hours. Yes,
The conductive layer according to claim 1 or 2, wherein the coating layer has a compression set of 1 to 10% under the conditions of a temperature of 125 ° C, a compression rate of 25%, and a compression time of 22 hours. Sex roller
A fourth aspect of the present invention is an image forming apparatus including the conductive roller according to any one of the first to third aspects.

  The conductive roller according to the present invention includes a coating layer formed by curing a composition containing a specific component on the outer peripheral surface of the conductive elastic layer. Or, even if the installation environment changes, it is possible to prevent contamination of the contacted body with which the conductive roller comes into contact or pressure contact, charging characteristics with respect to the developer or the recording medium, and the conductive elastic layer and Since the restoration characteristics of the coat layer can be maintained at a high level, a high-quality image can be formed.

  Therefore, according to the present invention, even when the use environment or the installation environment changes, it is possible to prevent the contacted body from being contaminated and to be able to form a high-quality image as desired. A roller can be provided, and an image forming apparatus that is not affected by the use environment or the installation environment can be provided.

  As shown in FIG. 1, a conductive roller according to an embodiment of the present invention includes a shaft body 2, a conductive elastic layer (hereinafter sometimes simply referred to as an elastic layer) 3, and a coat layer. 4 and disposed in the image forming apparatus shown in FIGS. 2 and 3, for example.

  The shaft body 2 only needs to have good conductive properties, and is usually a so-called “core” made of iron, aluminum, stainless steel, brass, or the like. Further, the shaft body 2 may be a shaft body that is made conductive by plating an insulating core body such as a thermoplastic resin or a thermosetting resin. Furthermore, the shaft body 2 may be a thermoplastic resin or a thermosetting resin. The shaft body may be formed of a conductive resin in which carbon black or metal powder is blended as a conductivity imparting agent. When the shaft body 2 is disposed in the image forming apparatus or the like shown in FIGS. 2 and 3, one end of the shaft body 2 is grounded or a bias voltage is applied. Functions such as injection of electric charge into the agent and development of the latent image by conveying the developer from the image carrier are exhibited.

The elastic layer 3 is formed by curing a conductive composition described later on the outer peripheral surface of the shaft body 2. The elastic layer 3 preferably has a volume resistivity of 10 ¹ to 10 ⁷ Ω · cm. When the elastic layer 3 has a volume resistivity of 10 ¹ to 10 ⁷ Ω · cm, even if the non-conductive coating layer 4 is formed on the outer peripheral surface of the elastic layer 3, the charging characteristics of the conductive roller 1. For example, when the conductive roller 1 is used as the developing roller of the image forming apparatus, the developer can be charged as desired, so that the developer can be carried as desired. The supported developer can be supplied to the image carrier as desired. The volume resistivity of the elastic layer 3 is more preferably 10 ² to 10 ⁶ Ω · cm, and more preferably 10 ³ to 10 ⁵ Ω · cm, in that the charging property of the conductive roller 1 is further improved. Particularly preferred. The volume resistivity of the elastic layer 3 can be adjusted within the above range by adjusting the content of the conductivity imparting agent contained in the elastic layer 3. The volume resistivity of the elastic layer 3 can be measured by setting the applied voltage to 100 V according to the method specified in JIS K6911.

  The elastic layer 3 preferably has a JIS A hardness of 20 to 70. When the elastic layer 3 has a JIS A hardness of 20 to 70, the contact area between the conductive roller 1 and the contacted body can be increased, and the rebound resilience and compression set of the elastic layer 3 can be increased. Is excellent. The JIS A hardness is 30 to 60 in that the contact area between the conductive roller 1 and the contacted body is improved, and the rebound resilience and compression set of the elastic layer 3 can be improved as desired. Is more preferable, and it is especially preferable that it is 35-50. The JIS A hardness can be measured according to JIS K6301.

  The elastic layer 3 preferably has a compression set of 0.1 to 9%. When the elastic layer 3 has a compression set of 0.1 to 9%, the elastic layer 3 is excellent in restoring characteristics, so that the concave portions of the elastic layer 3 and the coat layer 4 that are generated by being pressed against the contacted body or the like are quickly formed. It can be restored and fully perform its initial functions. For example, when the conductive roller 1 is disposed as a developing roller in the image forming apparatus, the concave portions generated by the image carrier and / or the developer amount adjusting means are quickly restored, so that the developer is as desired. Since the developer can be supplied to the image carrier as desired, it can contribute to the formation of a high-quality image. The compression set is more preferably 1 to 8%, and particularly preferably 2 to 7%, in that the restoring characteristics of the elastic layer 3 and the coat layer 4 can be further improved. The compression set of the elastic layer 3 is obtained by using a disk-shaped test piece (large test piece) having a diameter of 29 mm and a thickness of 12.5 mm, which is formed of the same conductive composition as that of the elastic layer 3. Compression set value of a disk-shaped test piece measured in accordance with “5. Compression set test” described in JIS K6262 under the conditions that the compression ratio is 25%, the test temperature is 125 ° C. and the test time is 22 hours. And

  The elastic layer 3 has a thickness of 1 mm or more in that a uniform nip width between the contacted body and the elastic layer 3 can be secured in a contact state with the contacted body. Preferably, it is 5 mm or more. On the other hand, the upper limit of the thickness of the elastic layer 3 is not particularly limited as long as the accuracy of the outer diameter of the elastic layer 3 is not impaired. In general, if the thickness of the elastic layer 3 is excessively increased, the production cost of the elastic layer 3 increases. Therefore, in consideration of practical production costs, the thickness of the elastic layer 3 is preferably 30 mm or less, and more preferably 20 mm or less. The thickness of the elastic layer 3 is appropriately selected according to the hardness of the elastic layer 3, such as JIS A hardness, in order to achieve a desired nip width.

  The conductive composition forming the elastic layer 3 contains rubber, a conductivity imparting agent, and various additives as desired.

  The rubber is not particularly limited. For example, silicone or silicone-modified rubber, nitrile rubber, ethylene propylene rubber (including ethylene propylene diene rubber), styrene butadiene rubber, butadiene rubber, isoprene rubber, natural rubber, acrylic rubber, chloroprene. Examples thereof include rubbers such as rubber, butyl rubber, epichlorohydrin rubber, urethane rubber, and fluororubber. Silicone or silicone-modified rubber is preferable from the viewpoint of excellent heat resistance and charging characteristics. These rubbers may be a liquid type or a millable type, and can be appropriately selected according to the molding method of the elastic layer 3, characteristics required for the elastic layer 3, and the like.

  The conductivity-imparting agent is not particularly limited as long as it has conductivity, and examples thereof include conductive powder and ion conductive material. More specifically, examples of the conductive powder include carbons for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT in addition to conductive carbon such as ketjen black and acetylene black. In addition, metals such as titanium oxide, zinc oxide, nickel, copper, silver, germanium, and conductive polymers such as metal oxides, polyaniline, polypyrrole, polyacetylene, etc. can be mentioned. Specific examples include inorganic ionic conductive materials such as sodium perchlorate, lithium perchlorate, calcium perchlorate, and lithium chloride. The conductivity imparting agent is added in an appropriate content so that a desired volume resistivity can be obtained when the elastic layer 3 is used singly or in combination of two or more. For example, the content of the conductivity-imparting agent in the conductive composition can be 2 to 80 parts by mass with respect to 100 parts by mass of the rubber.

  The conductive composition may contain various additives usually contained in various compositions in addition to the rubber and the conductivity imparting agent. Examples of the various additives include a chain extender and a crosslinking agent. Auxiliaries such as additives, catalysts, dispersants, foaming agents, antioxidants, antioxidants, fillers, pigments, colorants, processing aids, softeners, plasticizers, emulsifiers, heat resistance improvers, flame retardancy An improver, an acid acceptor, a thermal conductivity improver, a release agent, a solvent and the like can be mentioned. These various additives may be commonly used additives or may be specially used additives depending on applications.

  The conductive composition is made of a rubber kneader such as a two-roller, a three-roller, a roll mill, a Banbury mixer, a dough mixer (kneader), etc. Until mixing, for example, it is obtained by kneading at normal temperature or under heating for several minutes to several hours, preferably 5 minutes to 1 hour.

  The conductive composition should have a viscosity of 5 to 500 Pa · s at 25 ° C., for example, in that it can be easily and uniformly injected into a molding die. It is particularly good to have a viscosity of The viscosity of the conductive composition can be usually adjusted by the type and / or blending amount of each component contained therein. If necessary, the viscosity can be adjusted with a solvent or the like.

  Examples of the conductive composition that is preferably used include an addition curable millable conductive silicone rubber composition and an addition curable liquid conductive silicone rubber composition.

  The addition-curable millable conductive silicone rubber composition is (A) an organopolysiloxane represented by the following average composition formula (1), (B) a filler, and (C) other than those belonging to the component (B). Containing the conductive material.

R _n SiO _{(4-n) / 2} (1)
Here, R is a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different, preferably a monovalent hydrocarbon group having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms. Yes, n is a positive number from 1.95 to 2.05.

  R is, for example, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group and a dodecyl group, a cycloalkyl group such as a cyclohexyl group, an alkenyl such as a vinyl group, an allyl group, a butenyl group and a hexenyl group. Group, aryl groups such as phenyl and tolyl groups, aralkyl groups such as β-phenylpropyl group, and part or all of hydrogen atoms bonded to carbon atoms of these groups are substituted with halogen atoms or cyano groups A chloromethyl group, a trifluoropropyl group, a cyanoethyl group, etc. are mentioned.

  In the (A) organopolysiloxane, the molecular chain end is preferably blocked with a trimethylsilyl group, a dimethylvinyl group, a dimethylhydroxysilyl group, a trivinylsilyl group or the like. This organopolysiloxane preferably has at least two alkenyl groups in the molecule, and specifically, 0.001 to 5 mol%, particularly 0.01 to 0.5 mol% of alkenyl groups in R. It is preferable to have a vinyl group. In particular, when a platinum catalyst and an organohydrogenpolysiloxane are used in combination as a curing agent described later, an organopolysiloxane having such an alkenyl group is usually used.

  In addition, this organopolysiloxane can be obtained by cohydrolyzing and condensing one or more selected organohalosilanes, or by converting cyclic polysiloxanes such as siloxane trimers or tetramers into alkaline or It can be obtained by ring-opening polymerization using an acidic catalyst. This organopolysiloxane is basically a linear diorganopolysiloxane, but may be partially branched. Further, it may be a mixture of two or more different molecular structures. This organopolysiloxane usually has a viscosity of 100 cSt or more at 25 ° C., preferably 100,000 to 10,000,000 cSt. The organopolysiloxane usually has a degree of polymerization of 100 or more, preferably 3,000 or more, and an upper limit of preferably 100,000, and more preferably 10,000.

The (B) filler is not particularly limited, but a silica-based filler can be used. Examples of the silica-based filler include fumed silica, precipitated silica, etc., and surface-treated silica having a high reinforcing effect, which is surface-treated with a silane coupling agent represented by a general formula RSi (OR ′) _3. System fillers are preferred. Here, R in the general formula is a glycidyl group, vinyl group, aminopropyl group, methacryloxy group, N-phenylaminopropyl group, mercapto group or the like, and R ′ in the general formula is a methyl group or an ethyl group. . The silane coupling agent represented by the general formula can be easily obtained, for example, as trade names “KBM1003” and “KBE402” manufactured by Shin-Etsu Chemical Co., Ltd. Such a silica-based filler surface-treated with a silane coupling agent can be obtained by treating the surface of the silica-based filler according to a conventional method. In addition, a commercial item may be used for the silica type filler surface-treated with the silane coupling agent. M.M. A trade name “Zeothix 95” manufactured by HUBER Co., Ltd. is available. The compounding amount of the silica-based filler is preferably 11 to 39 parts by mass, particularly preferably 15 to 35 parts by mass with respect to 100 parts by mass of the (A) organopolysiloxane. The average particle size of the silica-based filler is preferably 1 to 80 μm, and particularly preferably 2 to 40 μm. The average particle diameter of the silica-based filler can be measured as a weight average value (or median diameter) or the like using, for example, a particle size distribution measuring apparatus such as a laser light diffraction method.

  The conductive material (C) is a conductive material that does not belong to the filler (B), and even if it is made of the same material physically and chemically, it is defined as the filler (B) and filled with silica. The conductive material having a different form and state from the material belongs to (C) the conductive material. Such an electroconductive material is an electroconductivity imparting component, for example, the said electroconductivity imparting agent is mentioned, Among these, carbon black is preferable. A conductive material may be used independently or may use 2 or more types together.

  The addition curable type millable conductive silicone rubber composition can contain various compounds as long as the object of the present invention is not impaired, and if necessary. For example, examples of various compounds or additives include a curing agent and fine silica powder.

  Examples of the curing agent include a curing agent obtained by combining a known platinum-based catalyst and an organohydrogenpolysiloxane, and an organic peroxide. As the platinum-based catalyst, a known catalyst can be used, specifically, platinum element simple substance, platinum compound, platinum complex, chloroplatinic acid, chloroplatinic acid alcohol compound, aldehyde compound, ether compound, Examples include complexes with various olefins. The content of the platinum-based catalyst may be an effective amount, that is, a so-called catalytic amount. For example, it is preferably 1 to 2,000 ppm in terms of platinum group metal with respect to (A) the organopolysiloxane.

The organohydrogenpolysiloxane may be linear, branched or cyclic, and the degree of polymerization is preferably 300 or less, and a diorganopolysiloxane having a dimethylhydrosilylsilyl group blocked at the end. , A copolymer having a terminal trimethylsiloxy group and comprising a dimethylsiloxane unit and a methylhydrodienesiloxane unit, a low viscosity fluid comprising a dimethylhydrodienesiloxane unit (H (CH ₃ ) ₂ SiO _1/2 and SiO ₂ unit, 1 , 3,5,7-tetrahydrodiene-1,3,5,7-tetramethylcyclotetrasiloxane, 1-propyl-3,5,7-trihydrodiene-1,3,5,7-tetramethylcyclo Examples include tetrasiloxane and 1,5-dihydrodiene-3,7-dihexyl-1,3,5,7-tetramethylcyclotetrasiloxane. The content of the hydrodiene polysiloxane is preferably used in such a ratio that the hydrogen atom directly bonded to the silicon atom is 50 to 500 mol% with respect to the alkenyl group of the (A) organopolysiloxane.

  Examples of the organic peroxide include di-t-butyl peroxide, alkyl peroxides such as 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, and dicumyl peroxide. Organic peroxides such as aralkyl peroxide can be mentioned. The content of the organic peroxide may be an effective amount, and for example, it is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of (A) organopolysiloxane.

The silica fine powder is suitable for obtaining a good elastic layer 3 of the mechanical strength, the BET specific surface area for the purpose ^{10 m} 2 / g or more, preferably fine silica 50 to 400 m ² / g It is preferable to use a powder. Examples of such silica fine powder include fumed silica (dry silica) and precipitated silica (wet silica), and fumed silica is preferred. When silica fine powder is added to the addition-curable millable conductive silicone rubber composition, the content of the silica fine powder is 5 to 100 parts by mass with respect to 100 parts by mass of (A) organopolysiloxane. Is preferable, it is more preferable that it is 5-90 mass parts, and it is especially preferable that it is 10-50 mass parts. If the content is less than 5 parts by mass, the desired reinforcing effect may not be obtained, and if it exceeds 100 parts by mass, the workability may be deteriorated. The average particle diameter of the silica fine powder is preferably 1 to 80 nm, and particularly preferably 5 to 50 nm. The average particle diameter of the silica fine powder can be measured as a weight average value (or median diameter) or the like using, for example, a particle size distribution measuring apparatus such as a laser light diffraction method.

  The addition-curable millable conductive silicone rubber composition may also contain other additives. Other additives include, for example, colorants, heat resistance improvers such as iron octylate, iron oxide, and cerium oxide, acid acceptors, heat conductivity improvers, mold release agents, alkoxysilanes, and the degree of polymerization of organopolysiloxane ( A) Lower dimethylsiloxane oil and silanol, for example, diphenylsilanediol, α, ω-dimethylsiloxanediol, etc. Examples thereof include various carbon functional silanes, and various cured or uncured olefin elastomers that do not inhibit the crosslinking reaction.

The addition-curable liquid conductive silicone rubber composition comprises (D) an organopolysiloxane containing at least two alkenyl groups bonded to silicon atoms in one molecule, and (E) bonded to silicon atoms in one molecule. An organohydrogenpolysiloxane containing at least two hydrogen atoms; (F) an inorganic filler having an average particle size of 1 to 30 μm and a bulk density of 0.1 to 0.5 g / cm ³ ; and (G). An addition-curable liquid conductive silicone rubber composition containing a conductivity imparting agent and (H) an addition reaction catalyst can be mentioned.

  As said (D) organopolysiloxane, the compound shown by the following average compositional formula (2) is suitable.

R ¹ _a SiO _{(4-a) / 2} (2)
Here, R ¹ in the average composition formula (2) is the same or different monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, and a is It is a positive number in the range of 1.5 to 2.8, preferably 1.8 to 2.5, more preferably 1.95 to 2.02.

R ¹ represents an alkyl group, an aryl group, an aralkyl group, an alkenyl group, and one of these hydrogen atoms, as exemplified by R of the organopolysiloxane (A) contained in the addition-curable millable conductive silicone rubber composition. Examples include hydrocarbon groups in which part or all are substituted with halogen atoms or cyano groups. At least two of R ¹ are alkenyl groups, particularly vinyl groups, and preferably 90% or more are methyl groups. Specifically, the alkenyl group content in the organopolysiloxane is 1.0 × 10 ^{−6 to} 5.0 × 10 ⁻³ mol / g, particularly 5.0 × 10 ^{−6 to} 1.0 × 10 ^−. It is preferably ³ mol / g.

  The degree of polymerization of the organopolysiloxane may be liquid at room temperature (25 ° C.) (for example, the viscosity at 25 ° C. is 100 to 1,000,000 mPa · s, preferably about 200 to 100,000 mPa · s). The average degree of polymerization is preferably from 100 to 800, particularly preferably from 150 to 600.

  The (E) organohydrogenpolysiloxane is represented by the following average composition formula (3), and is at least 2, preferably 3 or more (usually 3 to 200), more preferably 3 to 100 in one molecule. Those having hydrogen atoms bonded to silicon atoms are preferably used.

R ² _b H _c SiO _{(4-b-c) / 2} (3)
Here, R ² in the average composition formula (3) is the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms. Further, b is 0.7 to 2.1, c is 0.001 to 1.0, and b + c is a positive number satisfying 0.8 to 3.0.

  The content of hydrogen atoms (Si—H) bonded to the silicon atoms is preferably 0.001 to 0.017 mol / g, particularly 0.002 to 0.015 mol / g in the organohydrogenpolysiloxane.

Examples of the organohydrogenpolysiloxane (E) include trimethylsiloxy group-capped methylhydrogen polysiloxane at both ends, trimethylsiloxy group-capped dimethylsiloxane / methylhydrogensiloxane copolymer at both ends, and dimethylhydrogensiloxy group-capped dimethyl at both ends. Polysiloxane, both ends dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, both ends trimethylsiloxy group-blocked methylhydrogensiloxane / diphenylsiloxane copolymer, both ends trimethylsiloxy group-blocked methylhydrogensiloxane diphenylsiloxane-dimethylsiloxane _copolymers, copolymers consisting of _(CH 3) 2 _{HSiO 1/2} units and _{SiO 4/2} units, and, (C _{3) 2} HSiO _1/2 units and _{SiO 4/2} units and _{(C 6} H ₅₎ copolymers composed of _{SiO 3/2} units and the like.

  The compounding amount of the organohydrogenpolysiloxane (E) is preferably 0.1 to 30 parts by mass, particularly 0.3 to 20 parts by mass with respect to 100 parts by mass of the (D) organopolysiloxane. preferable. (D) The molar ratio of hydrogen atoms bonded to silicon atoms relative to the alkenyl groups of the organopolysiloxane is preferably 0.3 to 5.0, particularly preferably 0.5 to 2.5. .

The (F) inorganic filler is an important component for obtaining low roller permanent set, volume resistivity being stable over time, and sufficient roller durability. The inorganic filler has an average particle size of 1 to 30 μm, preferably 2 to 20 μm, and a bulk density of 0.1 to 0.5 g / cm ³ , preferably 0.15 to 0.45 g / cm ³ . If the average particle size is less than 1 μm, the electrical resistivity may change over time, and if it is greater than 30 μm, the durability of the elastic layer 3 may be reduced. If the bulk density is less than 0.1 g / cm ³ , the compression set may deteriorate and the electrical resistivity may change over time. If it exceeds 0.5 μm, the elastic layer 3 has insufficient strength and is durable. May decrease. The average particle diameter can be determined as a weight average value (or median diameter), for example, using a particle size distribution measuring device such as a laser diffraction method, and the bulk density is a measurement of the apparent specific gravity according to JIS K 6223. It can be determined based on the method.

  Examples of such inorganic fillers include diatomaceous earth, pearlite, mica, calcium carbonate, glass flakes, and hollow fillers, among which diatomaceous earth, pearlite, and foamed pearlite are preferable.

  The blending amount of the inorganic filler is preferably 5 to 100 parts by mass, particularly preferably 10 to 80 parts by mass with respect to 100 parts by mass of (D) organopolysiloxane.

  The said (G) electroconductivity imparting agent is the same as that of the said electroconductivity imparting agent, The compounding quantity can be 2-80 mass parts with respect to 100 mass parts of (D) organopolysiloxane.

  Examples of the (H) addition reaction catalyst include platinum black, platinous chloride, chloroplatinic acid, a reaction product of chloroplatinic acid and a monohydric alcohol, a complex of chloroplatinic acid and an olefin, platinum bisacetoacetate, palladium And catalyst based on rhodium and rhodium. The addition amount of the addition reaction catalyst can be a catalytic amount. For example, the amount of platinum group metal is 0.000 relative to the total mass of (D) organopolysiloxane and (E) organohydrogenpolysiloxane. It is preferably 5 to 1,000 ppm, particularly preferably about 1 to 500 ppm.

  This addition curable liquid conductive silicone rubber composition is a low molecular siloxane ester, a silanol, for example, a dispersant such as diphenylsilanediol, an improved heat resistance such as iron oxide, cerium oxide, iron octylate, etc. Agents, various carbon functional silanes that improve adhesion and moldability, halogen compounds that impart flame retardancy, and the like may be included within a range that does not impair the object of the present invention.

  The addition-curable liquid conductive silicone rubber composition preferably has a viscosity of 5 to 500 Pa · s, particularly preferably 10 to 200 Pa · s, at 25 ° C.

  The coat layer 4 is formed by curing a composition described later on the outer peripheral surface of the elastic layer 3. The coat layer 4 preferably has a compression set of 1 to 10%. When the coating layer 4 has a compression set of 1 to 10%, the restoration characteristics of the coating layer 4 are excellent, so that the concave portions of the coating layer 4 that are generated by being pressed by the contacted body etc. are quickly restored, The initial function can be fully exhibited. For example, when the conductive roller 1 is disposed as a developing roller in the image forming apparatus, the concave portions generated by the image carrier and / or the developer amount adjusting means are quickly restored, so that the developer is as desired. Since the developer can be supplied to the image carrier as desired, it can contribute to the formation of a high-quality image. The compression set is more preferably from 2 to 9%, particularly preferably from 3 to 8%, in that the restoring characteristics of the coat layer 4 can be further improved. The compression set of the coat layer 4 is obtained by using a disc-shaped test piece (large test piece) having a diameter of 29 mm and a thickness of 12.5 mm formed of the same composition as that of the coat layer 4. The compression set value of the disk-shaped test piece measured in accordance with “5. Compression set test” described in JIS K6262 under the conditions that the compression ratio is 25%, the test temperature is 125 ° C., and the test time is 22 hours. .

  The coat layer 4 preferably has a JIS A hardness of 30 to 80. When the coat layer 4 has a JIS A hardness of 30 to 80, the contact area between the conductive roller 1 and the contacted body can be increased, and the rebound resilience and compression set of the coat layer 4 can be increased. Is excellent. The JIS A hardness is 40 to 70 in that the contact area between the conductive roller 1 and the contacted body is improved and the impact resilience and compression set of the coat layer 4 can be improved as desired. Is more preferable, and it is especially preferable that it is 45-60. The JIS A hardness can be measured according to JIS K6301.

  The coat layer 4 preferably has a total concentration of extracted components of 100 ppm or less when extracted (refluxed) for 6 hours using a Soxhlet extractor with xylene as a solvent. When the total concentration of the extracted components extracted from the coat layer 4 is 100 ppm or less, even when the use environment or the installation environment changes when the conductive roller 1 is disposed in the image forming apparatus, Contamination to the body can be effectively prevented. The total concentration of the extracted components extracted from the coat layer 4 is more preferably 80 ppm or less in that the contamination to the contacted body can be effectively prevented over a long period of time, and it is 70 ppm or less. Is particularly preferred. The lower limit of the total concentration of the extracted components is preferably 0 ppm, but may be, for example, 10 ppm for preventing contamination of the contacted body. The total concentration of the extracted components was determined by putting a test piece cut out of a part of the coat layer 4 or a test piece separately prepared from the composition forming the coat layer 4 into xylene and refluxing xylene for 6 hours. The total concentration of various components extracted into xylene is calculated as a ratio to the total mass of the test piece.

  The coat layer 4 preferably has a surface roughness Rz of 1 to 15 μm. When the coating layer 4 has a surface roughness Rz of 1 to 15 μm, for example, when the conductive roller 1 is used as a developing roller, the developer is supported in a desired manner, and the image bearing member has a desired surface roughness Rz. Can be supplied as The surface roughness Rz is more preferably 2 to 14 μm, and particularly preferably 2 to 13 μm. The surface roughness Rz of the coat layer 4 is in accordance with JIS B 0601-1984 (10-point average roughness), and is a surface roughness meter (trade name “590A”, manufactured by Tokyo Seimitsu Co., Ltd.) equipped with a measurement probe having a tip radius of 2 μm. ), The conductive roller 1 provided with the coating layer 4 is set, and the surface roughness is measured at least at three points by a measurement length of 2.4 mm, a cutoff wavelength of 0.8 mm, and a cutoff type of Gaussian, and the average value thereof is measured. Is the surface roughness Rz.

  In general, the coat layer 4 preferably has a layer thickness of 0.1 to 50 μm, and more preferably has a layer thickness of 10 to 20 μm.

The coat layer 4 may or may not have conductivity, and the conductive roller 1 according to the present invention has a temperature of 20 due to the conductivity of the coat layer 4 or the conductivity of the elastic layer 3. The volume resistivity at 10 ° C. and a relative humidity of 50% is preferably 10 ¹² Ω · cm or less. When the conductive roller 1 has a volume resistivity of 10 ¹² Ω · cm or less, the charging characteristics are excellent. For example, when the conductive roller 1 is used as a developing roller of an image forming apparatus, a developer is used. Since it can be charged as desired, the developer can be carried as desired, and the carried developer can be supplied to the image carrier as desired. In view of further excellent charging characteristics, the volume resistivity of the conductive roller 1 is more preferably 10 ¹⁰ Ω · cm or less, and particularly preferably 10 ³ to 10 ⁹ Ω · cm. The volume resistivity of the conductive roller 1 can be adjusted within the above range by adjusting the content of the conductivity imparting agent contained in the coat layer 4 and / or the volume resistivity of the elastic layer 3. The measurement method can be the same as the volume resistivity of the elastic layer 3.

  The composition forming the coat layer 4 is a urethane containing 100 parts by mass of a polyurethane preparation component, 1 to 10 parts by mass of a silicone graft acrylic resin, and 1 to 10 parts by mass of a silane coupling agent having an amino group. It is a composition.

  The polyurethane preparation component may be any component that can form polyurethane. For example, a mixture of a polyol and a polyisocyanate, a prepolymer obtained by reacting a polyol and a polyisocyanate, and a polyol and a polyisocyanate And at least one component selected from the group consisting of polyurethanes obtained by reacting.

  The polyol in the mixture of polyol and polyisocyanate may be any of various polyols usually used in the preparation of polyurethane, but at least one polyol selected from polyether polyols and polyester polyols is used as a coating. The layer 4 is preferable in that it is excellent in wear resistance, electrical stability, water resistance and the like. Examples of the polyether polyol include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polypropylene glycol-ethylene glycol, polytetramethylene ether glycol, copolymer polyols of tetrahydrofuran and alkylene oxide, and various modified products thereof. These mixtures etc. are mentioned. Examples of the polyester polyol include condensed polyester polyols, lactone polyester polyols, polycarbonate polyols, and mixtures thereof obtained by condensation of dicarboxylic acids such as adipic acid and polyols such as ethylene glycol. The polyether polyol and polyester polyol may be used singly or in combination of two or more, or a polyether polyol and a polyester polyol may be used in combination. The polyol is preferably a polyester polyol because it is excellent in thermal stability. The polyol preferably has a number average molecular weight of 1000 to 8000, more preferably 1000 to 5000, in view of excellent compatibility with polyisocyanate and the like described later. The number average molecular weight is a molecular weight when converted to standard polystyrene by gel permeation chromatography (GPC).

  The polyisocyanate in the mixture of polyol and polyisocyanate may be any of various polyisocyanates usually used in the preparation of polyurethane, and examples thereof include aliphatic polyisocyanates and aromatic polyisocyanates. The polyisocyanate is preferably an aromatic polyisocyanate in terms of excellent storage stability and easy control of the reaction rate. Examples of the aromatic polyisocyanate include xylylene diisocyanate (XDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), naphthalene diisocyanate (NDI), paraphenylene diisocyanate (PDI), and tolidine diisocyanate (TODI). It is done. Examples of the aliphatic polyisocyanate include hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), norbornane diisocyanate methyl, transcyclohexane-1,4-diisocyanate, and hydrogenated MDI.

  In addition to these polyisocyanates, block polyisocyanates in which isocyanate groups are blocked with a blocking agent are preferably used as the polyisocyanate. Block polyisocyanate has high stability at room temperature and has advantages such as easy handling because the blocking agent is released by heating and the isocyanate group is regenerated. In particular, it has an advantage that it reacts stably even in summer when the humidity is high, and can be used in combination with a reagent having an active group having a high reactivity such as an amino group. Examples of the blocking agent include ε-caprolactams, methyl ethyl ketoximes, 3,5-dimethylpyrazoles, alcohols and phenols. Examples of the blocking agent include isocyanates. In this case, the blocked polyisocyanate is a polyisocyanate dimer (polyuretdione). As the blocking agent, any of the above can be used, but ε-caprolactams and methyl ethyl ketoximes are preferred from the viewpoint of excellent compatibility with the solvent.

  The polyisocyanate preferably has a molecular weight of 500 to 2000, more preferably 700 to 1500.

  The mixing ratio in the mixture of polyol and polyisocyanate is not particularly limited. Usually, hydroxyl group (OH) contained in polyol and isocyanate group contained in polyisocyanate (NCO, isocyanate group that can be liberated in the case of block polyisocyanate) ) Is preferably 0.7 to 1.15 in that the desired degree of crosslinking in the resulting polyurethane can be achieved. This molar ratio (NCO / OH) is more preferably 0.85 to 1.10. From the viewpoint that hydrolysis of polyurethane can be prevented.

  In a mixture of a polyol and a polyisocyanate, the composition contains, in addition to the polyol and the polyisocyanate, auxiliary agents usually used for the reaction between the polyol and the polyisocyanate, such as a chain extender and a crosslinking agent. May be. Examples of chain extenders and crosslinking agents include glycols, hexanetriol, trimethylolpropane, and amines.

  The prepolymer and the polyurethane may be any prepolymer and polyurethane obtained by reacting the polyol and the polyisocyanate, and the molecular weight thereof is not particularly limited. The prepolymer and the polyurethane can be obtained by reacting a polyol and a polyisocyanate by the one-shot method or the prepolymer method in the presence of the auxiliary agent, if desired.

  The polyurethane preparation component is preferably a mixture of polyol and polyisocyanate, particularly preferably a mixture of at least one polyol selected from polyether polyol and polyester polyol and polyisocyanate. That is, the composition particularly preferably contains a mixture of at least one polyol selected from polyether polyol and polyester polyol and polyisocyanate.

  The silicone-grafted acrylic resin has a main chain containing a linear structure portion derived from an acrylic monomer and / or a methacrylic monomer, and a side chain containing a polysiloxane structure portion derived from a siloxane unit. It is a grafted resin. Examples of acrylic monomers include acrylic acid alkyl esters and acrylic acid aryl esters. Examples of methacrylic monomers include methacrylic acid alkyl esters and methacrylic acid aryl esters. The alkyl group constituting the ester is preferably an alkyl group having 1 to 10 carbon atoms such as a methyl group or an ethyl group. Examples of the polysiloxane include a dialkylsiloxane unit having an alkyl group having 2 to 18 carbon atoms such as a dimethylsiloxane unit, an alkylarylsiloxane unit such as a methylphenylsiloxane unit, a diarylsiloxane unit such as a diphenylsiloxane unit, and a methyltrisiloxane unit. Examples include polysiloxanes obtained by polymerizing at least one of fluorinated siloxane units such as fluoropropylsiloxane units, and among these, polysiloxanes obtained by polymerizing dialkylsiloxane units having an alkyl group having 2 to 18 carbon atoms. Polysiloxane obtained by polymerizing dimethylsiloxane units is particularly preferable.

The silicone graft acrylic resin preferably has a number average molecular weight of 1.0 × 10 ^{2 to} 1.0 × 10 ⁷ in that the compatibility with the polyurethane preparation component is increased. When the number average molecular weight is less than 1.0 × 10 ² , the silicone graft acrylic resin may leak to the surface of the coat layer 4 and contaminate the contacted body, while the number average molecular weight is 1.0. If it exceeds 10 ⁷ , the compatibility with the polyurethane preparation component is lowered, and the coat layer 4 cannot be formed uniformly, and as a result, a high-quality image cannot be formed as desired. There is. The number average molecular weight of the silicone graft acrylic resin is 1.0 × 10 10 in that contamination of the contacted body can be effectively prevented and a high-quality image can be formed as desired. ^It is more preferably ^{3 to} 1.0 × 10 ⁶ , and particularly preferably 1.0 × 10 ^{4 to} 1.0 × 10 ⁵ . The number average molecular weight of the silicone graft acrylic resin is a molecular weight when converted to standard polystyrene by gel permeation chromatography (GPC).

  The silicone graft acrylic resin can effectively prevent the components constituting the elastic layer 3 and / or the coat layer 4 from leaking to the surface of the coat layer 4, and is excellent in the durability of the coat layer 4. In view of the above, it preferably has an active group that reacts with the urethane preparation component, for example, an active hydrogen-containing group such as a hydroxyl group, a carboxy group, an amide group, and an amino group, and particularly contains a hydroxyl group and / or a carboxy group. It is preferable. The functional group equivalent (g / mol) of the active group in the silicone graft acrylic resin is preferably 500 to 10,000, more preferably 800 to 7000, and particularly preferably 4000 to 6000.

The silicone graft acrylic resin may be appropriately produced by a conventional method, and a commercially available product can be used. For example, a silicone graft acrylic resin is obtained by copolymerizing a polysiloxane having a polymerizable reactive group containing a carbon-carbon double bond such as a vinyl group, an acryloyl group, or a methacryloyl group, and an acrylate ester or a methacrylate ester. Can be manufactured. On the other hand, as a commercially available silicone graft acrylic resin, for example, trade name “X-24-798A (number average molecular weight 1.4 × 10 ⁴ )” (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like can be mentioned. Examples of the silicone graft acrylic resin include a trade name “X-22-8004 (number average molecular weight 1.9 × 10 ⁴ , hydroxyl group equivalent 3250 g / mol)” (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like, and a silicone having a carboxy group As the graft acrylic resin, trade name “X-24-8195 (number average molecular weight 2.1 × 10 ⁴ , carboxy group equivalent 850 g / mol)” (manufactured by Shin-Etsu Chemical Co., Ltd.) and trade name “X-24- 8053 (number average molecular weight 2.2 × 10 ⁴ ) ”(manufactured by Shin-Etsu Chemical Co., Ltd.).

  Content of the silicone graft acrylic resin in the composition is 1 to 10 parts by mass with respect to 100 parts by mass of the polyurethane preparation component. When the content of the silicone graft acrylic resin is less than 1 part by mass, the effect of adding the silicone graft acrylic resin does not appear, filming phenomenon or the like may occur, and the quality of the formed image may be reduced. When the amount exceeds 10 parts by mass, the contacted object may not be effectively prevented from being contaminated. It is preferable that the content of the silicone graft acrylic resin is 2 to 9 parts by mass in that a higher quality image can be formed and contamination of the contacted body can be more effectively prevented. It is particularly preferably ˜8 parts by mass.

The amino group-containing silane coupling agent (hereinafter sometimes referred to as aminosilane coupling agent) may have at least one hydrolyzable silyl group and amino group in the molecule. For example, the formula R ¹ —SiR ² _m R ³ _(3-m) (wherein R ¹ is an amino group-containing group, R ² is an organic group, R ³ is a hydrolyzable group, m Is an integer of 0 to 2).

The amino group-containing group R ¹ may be a group containing an amino group, and examples thereof include an aminoalkyl group and an aminoaryl group. The number of carbon atoms of the amino group-containing group R ¹ is not particularly limited, For example, it is preferably about 1 to 20. The amino group contained in the amino group-containing group R ¹ may be any of a primary amino group, a secondary amino group (including an imino group), a tertiary amino group, and a quaternary amino group, but has excellent charging characteristics. And preferably a primary amino group, a secondary amino group, or a tertiary amino group. The amino group-containing group R ¹ may contain two or more amino groups. Examples of the aminoalkyl group include aminomethyl group, aminoethyl group, aminopropyl group, N-2- (aminoethyl) -3-aminopropyl group, N, N-dimethylaminopropyl group, and alkyl or aryl thereof. Examples of the aminoaryl group include an aminophenyl group, an aminobenzyl group, and alkyl or aryl substituents thereof.

Examples of the organic group R ² include alkyl groups and aryl groups having about 1 to 30 carbon atoms, and specific examples include a methyl group, an ethyl group, and a propyl group.

The hydrolyzable group R ³ may be any group that can easily hydrolyze the Si—R ³ bond in the presence of moisture, such as a halogen atom, an alkoxy group, a (meth) acryloyl group, a mercapto group, and the like. Examples include hydrolyzable substituents. Among these, an alkoxy group is preferable because it is easily available. Examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group.

  M is an integer of 0 to 2, and is preferably 0 or 1 and particularly preferably 0 in that the curing rate of the aminosilane coupling agent is high and desired properties can be exhibited. .

  Examples of the aminosilane coupling agent include 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylethyldiethoxysilane, 3-aminopropyldimethylethoxy. Silane, 3-aminopropylmethyldiethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (Aminoethyl) -3-aminopropyltriethoxysilane, N, N-dimethylaminopropyltrimethoxysilane, N, N-diethylaminopropyltrimethoxysilane, N, N-dipropylaminopropyltrimethoxysilane, N, N- Dibutylamino Propyltrimethoxysilane, N-monobutylaminopropyltrimethoxysilane, N, N-dioctylaminopropyltrimethoxysilane, N, N-dibutylaminopropylmethyldimethoxysilane, N, N-dibutylaminopropyldimethylmonomethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N, N-dimethylaminophenyltrimethoxysilane, trimethoxysilyl-3-propylphenylamine, trimethoxysilyl-3-propylbenzylamine , Trimethoxysilyl-3-propylpiperidine, trimethoxysilyl-3-propylmorpholine, trimethoxysilyl-3-propylimidazole, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylto Methoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane Etc.

  Content of the aminosilane coupling agent in the said composition is 1-10 mass parts with respect to 100 mass parts of said polyurethane preparation components. When the content of the aminosilane coupling agent is less than 1 part by mass, the charging characteristics with respect to the developer or the recording medium greatly change due to a change in the use environment or the installation environment, and the quality of the formed image is deteriorated. On the other hand, when the amount exceeds 10 parts by mass, the unreacted aminosilane coupling agent may leak to the surface of the coat layer 4 and contaminate the contacted body. The content of the aminosilane coupling agent is preferably 2 to 9 parts by mass in terms of being able to form a higher quality image and prevent contamination of the contacted body, and 4 to 7 parts by mass. It is particularly preferred.

  The composition may contain various additives usually contained in the composition in addition to the polyurethane preparation component, the silicone graft acrylic resin, and the aminosilane coupling agent. Examples of the various additives include the chain Auxiliary agents and auxiliary agents such as crosslinking agents, dispersants, foaming agents, anti-aging agents, antioxidants, fillers, pigments, colorants, processing aids, softeners, plasticizers, emulsifiers, heat resistance improvers, Examples include flame retardant improvers, acid acceptors, thermal conductivity improvers, mold release agents, and solvents. These various additives may be commonly used additives or may be specially used additives depending on applications.

  The composition is a polyurethane kneading machine such as a two-roller, three-roller, roll mill, Banbury mixer, dough mixer (kneader), etc., polyurethane preparation ingredients, silicone graft acrylic resin and aminosilane coupling agent, various additions as required It is obtained by kneading, for example, for several minutes to several hours, preferably 5 minutes to 1 hour at room temperature or under heating until the agent and the like are uniformly mixed.

  The composition may have a viscosity of 5 to 500 Pa · s at 25 ° C., for example, and can be easily formed on the outer peripheral surface of the elastic layer 3. It is particularly good to have The viscosity of the composition can usually be adjusted by the type and / or blending amount of each component contained therein. If necessary, the viscosity can be adjusted with a solvent or the like.

  The conductive roller 1 according to the present invention may have another layer between the elastic layer 3 and the coat layer 4. Examples of the other layer include a primer layer that adheres or adheres the elastic layer 3 and the coat layer 4 to each other. Examples of the material for forming the primer layer include alkyd resins, phenol-modified / silicone-modified alkyd resin modified products, oil-free alkyd resins, acrylic resins, silicone resins, epoxy resins, fluororesins, phenol resins, polyamide resins, urethanes. Examples thereof include resins and mixtures thereof. Moreover, as a crosslinking agent which hardens and / or bridge | crosslinks these resin, an isocyanate compound, a melamine compound, an epoxy compound, a peroxide, a phenol compound, a hydrogen siloxane compound etc. are mentioned, for example. The primer layer is formed with a thickness of 0.1 to 10 μm, for example.

  The conductive roller 1 according to the present invention is manufactured by forming the elastic layer 3 on the outer peripheral surface of the shaft body 2 and further forming the coat layer 4 on the outer peripheral surface of the elastic layer 3.

  First, the shaft body 2 is prepared. For example, the shaft body 2 is prepared in a desired shape by a known method. The shaft body 2 may be coated with a primer before the elastic layer 3 is formed. Although there is no restriction | limiting in particular as a primer apply | coated to the shaft body 2, The resin similar to the material which forms the primer layer which adheres or adheres the said elastic layer 3 and the coating layer 4, and a crosslinking agent are mentioned. The primer is dissolved in a solvent or the like as desired, and is applied to the outer peripheral surface of the shaft body according to a conventional method such as a dipping method or a spray method.

  The elastic layer 3 is formed by heat-curing the conductive composition on the outer peripheral surface of the shaft body 2. For example, the elastic layer 3 is formed on the outer peripheral surface of the shaft body 2 by performing heat curing and molding simultaneously or continuously by a known molding method. The method for curing the conductive composition may be any method that can apply heat necessary for curing the conductive composition, and the method for forming the elastic layer 3 may be continuous vulcanization by extrusion, pressing, molding by injection, etc. There is no particular limitation. For example, when the conductive composition is an addition curable millable conductive silicone rubber composition, for example, extrusion molding or the like can be selected, and the conductive composition is an addition curable liquid conductive silicone rubber composition. In this case, for example, a molding method using a mold can be selected. The heating temperature for curing the conductive composition is 100 to 500 ° C., particularly 120 to 300 ° C., in the case of an addition-curable millable conductive silicone rubber composition, and the time is several seconds to 1 hour, particularly 10 seconds or more. It is preferably ~ 35 minutes or less, and in the case of an addition curable liquid conductive silicone rubber composition, it is 100 to 300 ° C, particularly 110 to 200 ° C, and the time is 30 minutes to 5 hours, particularly 1 to 3 hours. Is preferred. In addition, in the case of an addition-curable millable conductive silicone rubber composition, if necessary, the curing conditions are about 100 to 200 ° C. for about 1 to 20 hours, and in the case of an addition-curable liquid conductive silicone rubber composition. Secondary vulcanization may be performed at 120 to 250 ° C. under curing conditions for about 30 to 70 hours. In addition, the conductive composition can be foamed and cured by a known method to easily form a sponge-like elastic layer having bubbles.

  The elastic layer 3 formed in this way has its surface polished and ground as desired to adjust the outer diameter, surface state, and the like. In particular, when the elastic layer 3 is formed of an addition curable type millable conductive silicone rubber composition, the surface should be polished and ground after the addition curable type millable conductive silicone rubber composition is heat cured. .

  In the elastic layer 3 thus formed, the primer layer may be formed before the coat layer 4 is formed. The primer layer, if necessary, dissolves the material in a solvent or the like, applies the material to the outer peripheral surface of the elastic layer 3 according to a conventional method, for example, a dip method, a spray method, etc. The material is heat cured.

  The coat layer 4 is formed by coating the composition on the outer peripheral surface of the elastic layer 3 thus formed or the primer layer formed as desired, and then heat-curing the applied composition. ,It is formed. Coating of the composition includes, for example, a coating method in which a coating liquid of the composition is coated, a dipping method in which the elastic layer 3 and the like are immersed in the coating liquid, and spray coating in which the coating liquid is sprayed on the elastic layer 3 and the like It is carried out by a known coating method such as a method. The composition may be applied as it is or volatile to the composition, for example, alcohols such as methanol and ethanol, aromatic solvents such as xylene and toluene, and ester solvents such as ethyl acetate and butyl acetate. You may apply the coating liquid which added the solvent. This coating liquid is a coating liquid in which the composition is dissolved or suspended, and contains, for example, about 80% by mass of a volatile solvent. The method for heat-curing the composition thus coated may be any method that can apply heat necessary for curing the composition. For example, the elastic layer 3 or the like coated with the composition is heated by a heater. The method of heating with is mentioned. The heating temperature when the composition is heat-cured is, for example, 100 to 200 ° C, particularly 130 to 160 ° C, and the heating time is preferably 10 to 120 minutes, particularly 30 to 60 minutes. In place of the coating, the composition is laminated on the outer peripheral surface of the elastic layer 3 or the primer layer by a known molding method such as extrusion molding, press molding, injection molding or the like, or after the lamination, A method of heating the laminated composition or the like can be employed.

  Since the conductive roller 1 has a coating layer 4 formed by curing the composition on the outer peripheral surface of the conductive elastic layer 3, when the conductive roller 1 is disposed in an image forming apparatus, the use environment or the installation environment, etc. Can be prevented from being contaminated even when the conductive roller 1 is in contact with or pressed against, and the charging characteristics with respect to the developer or the recording body, and the conductive elastic layer 3 and the coating layer can be prevented. 4 can be maintained at a high level, and as a result, a high-quality image can be formed. Accordingly, the conductive roller 1 is in contact with or pressed against an image carrier that is required to be highly prevented from being contaminated, and is a cleaning roller, a charging roller, a developing roller, and a transfer roller for an image forming apparatus. Is preferably used.

  Next, an example of an image forming apparatus provided with the conductive roller 1 according to the present invention (hereinafter sometimes referred to as an image forming apparatus according to the present invention) will be described with reference to FIG.

  As shown in FIG. 2, the image forming apparatus 10 is in contact with a rotatable image carrier 11 on which an electrostatic latent image is formed, for example, a photosensitive member (also referred to as a photosensitive drum), and the image carrier 11. Alternatively, it is provided in pressure contact or at a predetermined interval, and is provided above the image carrier 11 with a charging means 12 for charging the image carrier 11 such as a charging roller, and forms an electrostatic latent image on the image carrier 11. The exposure means 13 and the image carrier 11 are provided in contact with or pressure contact with each other or at a predetermined interval. The developer 22 is supplied to the image carrier 11 with a constant layer thickness to develop the electrostatic latent image. A developing unit 20 that is in pressure contact with the image carrier 11, and a transfer unit 14 such as a transfer roller that transfers the developed electrostatic latent image from the image carrier 11 onto a recording member 16 such as a recording sheet. The recording body 1 is provided downstream of the recording body 16 in the transport direction. Fixing means 15 for fixing the developer 22 transferred onto the image carrier 11, for example, a fixing device and the developer 22 not transferred to the recording medium 16 and remaining on the image carrier 11 and / or dust adhering to the image carrier 11 are removed. And a cleaning means 17. The fixing unit 15 includes a fixing roller 15a and a pressure roller 15b that are opposed to each other so as to sandwich the recording medium 16 that is conveyed.

  The developing unit 20 is disposed in the vicinity of the image carrier 11 and a housing 21 that contains a one-component non-magnetic developer 22, and the developer 22 contained in the housing 21 is placed in the image carrier. The developer carrying member 24 to be supplied to the developer 11, for example, a developing roller, and development made of an elastic material that adjusts the thickness of the developer 22 so that the developer 22 is held at a constant thickness on the surface of the developer carrying member 24 The agent amount adjusting means 25 includes a blade, for example, and a mounting means 26 for attaching the developer amount adjusting means 25 to the housing 21. In FIG. 2, reference numeral 23 indicates a stirring means for stirring the developer 22. In the image forming apparatus 10, the conductive roller 1 is mounted as a developer carrier 24, that is, a developing roller.

  According to the image forming apparatus 10, an image is formed on the recording body 16 as follows. That is, the exposure unit 13 forms an electrostatic latent image on the surface of the rotating image carrier 11. When the developer 22 is supplied from the developing means 20 to the image carrier 11 by the developer carrier 24, the developer 22 is electrostatically attached to the electrostatic latent image formed on the surface of the image carrier 11, and is statically charged. The electrostatic latent image is developed. When the recording medium 16 conveyed by the conveying means (not shown) is sandwiched between the transfer means 14 and the image carrier 11 and passes between them, the developed static image formed on the surface of the image carrier 11 is formed. The electrostatic latent image is transferred to the surface of the recording medium 16. The recording medium 16 to which the developed electrostatic latent image has been transferred is conveyed by the conveying means and reaches the fixing means 15. In the fixing unit 15, the conveyed recording medium 16 passes between the fixing roller 15 a and the pressure roller 15 b. The developer 22 that forms the developed electrostatic latent image existing on the surface of the recording medium 16 is melted by the fixing roller 15 a and fixed to the recording medium 16. Thus, an image by the developer 22 is formed on the surface of the recording medium 16.

  In such an image forming apparatus 10, the developer carrier 24 must be able to supply the developer 22 to the image carrier 11 at all times. If the developer 22 is uniformly supplied to the surface of the image carrier 11, the electrostatic latent image formed on the image carrier 11 is finely developed by the developer 22 and transferred onto the recording body 16. . The movement of the developer 22 during the development process will be described in more detail with reference to FIG. 2. The developer 22 charged by the developer carrier 24 adheres to the developer carrier 24 by electrostatic force and physical adhesion force. The developer 22 adhering to the surface of the rotating developer carrying member 24 is charged as desired by the developer carrying member 24 and the developer amount adjusting means 25 and has a constant thickness. It becomes a layer of an agent, and reaches the image carrier 11 rotating substantially in contact with the developer carrier 24. The image carrier 11 is charged by the charging means 12, and an electrostatic latent image is drawn thereon. The developer 22 in contact with the electrostatic latent image portion on the charged image carrier 11 adheres to the image carrier 11 side by electrostatic force and develops the electrostatic latent image. The electrostatic latent image developed on the image carrier 11 contacts the recording member 16 as the image carrier 11 rotates, and is transferred onto the recording member 16 by the transfer means 14. At this time, as described above, the developer 22 supplied from the developer carrier 24 is always in contact with the image carrier 11 in a uniform state, and adheres to the image carrier 11 side by controlled electrostatic force. is important. Thus, the developer carrier 24 is an important part for forming a high-quality image.

  When the conductive roller 1 according to the present invention is used as the developer carrier 24, the conductive roller 1 is in contact with or pressed against the conductive roller 1 even if the use environment or the installation environment changes. In addition to preventing the carrier 11 from being contaminated, the carrier 11 is excellent in charging characteristics for the developer or the recording medium, and the restoring characteristics of the conductive elastic layer 3 and the coating layer 4 are also high. Therefore, the image forming apparatus 10 including the conductive roller 1 can prevent the image carrier 11 from being contaminated even if the use environment or the installation environment is changed, and can produce a high-quality image as desired. An image forming apparatus capable of forming, that is, an image forming apparatus capable of forming a high-quality image without being affected by the use environment or the installation environment.

  Next, another example of the image forming apparatus according to the present invention will be described with reference to FIG. As shown in FIG. 3, the image forming apparatus 30 includes a plurality of image carriers 11B, 11C, 11M, and 11Y that are mounted on the developing units B, C, M, and Y of the respective colors in series on a transfer conveyance belt 32. Therefore, the development units B, C, M, and Y are arranged in series on the transfer conveyance belt 32. These developing units B, C, M, and Y are each configured similarly to the developing device in the image forming apparatus 10 shown in FIG. In FIG. 3, the stirring means 23 is omitted.

  The developers 22B, 22C, 22M and 22Y used in the image forming apparatus 30 may be either a dry developer or a wet developer as long as they can be charged by friction and can be fixed to the recording medium 16. A nonmagnetic developer or a magnetic developer may be used. The developing units B, C, M, and Y have a one-component non-magnetic black developer 22B, cyan developer 22C, magenta developer 22M, and yellow developer 22Y in the casings 21B, 21C, 21M, and 21Y, respectively. Is stored. In the image forming apparatus 30, the conductive roller 1 is mounted as a developer carrier 24B, 24C, 24M and 24Y, that is, as a developing roller.

  As shown in FIG. 3, the image carrier 11 and the transfer unit 14 in the developing units B, C, M, and Y are in contact with each other via a transfer conveyance belt 32 stretched between two support rollers 33. ing. The recording body 16 is transported by the transfer transport belt 32 so as to pass through the contact portion between the image carrier 11 and the transfer means 14.

  As shown in FIG. 3, at the bottom of the image forming apparatus 30, a cassette 31 is disposed as a recording body 16 in which a plurality of recording bodies are stacked and accommodated, and the recording body in the cassette 31 is a paper feed roller. Or the like, and is conveyed onto the transfer conveyance belt 32.

  As shown in FIG. 3, a fixing unit 15 that fixes the developer 22 (electrostatic latent image) transferred to the recording body 16 is disposed downstream in the conveyance direction of the recording body 16 in the image forming apparatus 30. . The fixing unit 15 is configured similarly to the transfer unit 15 in the image forming apparatus 10 shown in FIG.

  The image forming apparatus 30 forms a color image on the recording body 16 as follows. First, in the developing unit B, similarly to the image forming apparatus 10, the electrostatic latent image developed in black is visualized on the recording medium 16. Next, in the same manner as in the developing unit B, a cyan image, a magenta image, and a yellow image are superimposed on the recording medium 16 in which the electrostatic latent image is visualized as a black image by the developing units C, M, and Y, respectively. A color image is visualized. Next, the recording body 16 in which the color image is visualized is conveyed to the fixing unit 15, and the color image is fixed on the recording body 16 as a permanent image by the fixing unit 15. In this way, a color image can be formed on the recording medium 16.

  Since the tandem type image forming apparatus 30 includes the conductive roller 1 as the developer carrier 24, similarly to the image forming apparatus 10, the image carrier 11 can be used even if the use environment or the installation environment changes. Image forming apparatus capable of forming a high-quality image as desired, that is, being able to form a high-quality image without being influenced by the use environment or the installation environment. It is an image forming apparatus that can be used.

  The image forming apparatuses 10 and 30 are image forming apparatuses such as copiers, facsimiles, and printers. The image forming apparatuses 10 and 30 have been described with reference to the example in which the conductive roller 1 according to the present invention is used as a developing roller as an example of the developer carrier 24. Even if the conductive roller 1 according to the present invention is used as a roller that is disposed and can come into contact with the developer or the recording medium, for example, a cleaning roller, a charging roller, and a transfer roller, the developer is as desired. In addition, since the recording medium can be conveyed while being held at a predetermined position, a high-quality image can be formed.

  The image forming apparatuses 10 and 30 are electrophotographic image forming apparatuses. However, in the present invention, the image forming apparatus is not limited to the electrophotographic system, and is, for example, an electrostatic image forming apparatus. May be. The image forming apparatus provided with the conductive roller 1 according to the present invention transfers a monochrome image forming apparatus 10 having a single developing unit and a plurality of image carriers having developing units for each color. It is not limited to the tandem type color image forming apparatus 30 arranged in series on the conveyance belt. For example, in a four-cycle type color image forming apparatus that repeats primary transfer of a developer image carried on an image carrier onto an endless belt sequentially. There may be.

  The developer 22 used in the image forming apparatuses 10 and 30 is a one-component nonmagnetic developer. However, in the present invention, a one-component magnetic developer may be used, and a two-component nonmagnetic developer. Or a two-component magnetic developer.

(Examples 1-8 and Comparative Examples 1-9)
Each conductive roller of Examples 1-8 and Comparative Examples 1-9 was produced as follows. That is, a shaft body (made by SUM22, diameter 10 mm, length 275 mm) subjected to electroless nickel plating was washed with toluene, and a silicone primer (trade name “Primer No. 16”, Shin-Etsu Chemical Co., Ltd.) Applied). The shaft body subjected to the primer treatment was fired at a temperature of 150 ° C. for 10 minutes using a gear oven, and then cooled at room temperature for 30 minutes or more to form a primer layer on the surface of the shaft body.

On the other hand, 100 parts by weight of methyl vinyl silicone raw rubber (trade name “KE-78VBS”, manufactured by Shin-Etsu Chemical Co., Ltd.) and 20 parts by weight of dimethyl silicone raw rubber (trade name “KE-76VBS”, manufactured by Shin-Etsu Chemical Co., Ltd.) , 10 parts by mass of carbon black (trade name “Asahi Thermal”, manufactured by Asahi Carbon Co., Ltd.) and fumed silica-based filler (trade name “Zeothix 95”, average primary particle size 6.9 μm, bulk density 0.09 g / cm ³ , 15 parts by mass of JM HUBER Co., Ltd., platinum catalyst (trade name “C-19A”, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.5 part by mass, hydrogen polysiloxane (trade name “ C-19B "(manufactured by Shin-Etsu Chemical Co., Ltd.) 2.0 parts by mass and kneaded with a pressure kneader to give an addition-curable millable conductive silicone rubber composition It was manufactured.

  Next, the shaft body on which the primer layer was formed and the addition-curing type millable conductive silicone rubber composition were integrally extracted with a crosshead type extruder and heated at 250 ° C. for 30 minutes using a gear oven. Thereafter, using a gear oven, secondary heating was performed at 200 ° C. for 4 hours, and the mixture was allowed to stand at room temperature for 24 hours. Next, the surface of the elastic layer was polished by a cylindrical grinder so that the formed elastic layer had a diameter of 18 mm.

The volume resistivity and JIS A hardness of the elastic layer thus formed were measured by the above method. The volume resistivity was 2 × 10 ⁴ Ω · cm and the JIS A hardness was 40.

  In addition, using the addition-curable type millable conductive silicone rubber composition, three specimens each having a flat plate-shaped test piece having the above dimensions were prepared. Using this large specimen, the compression set of this large specimen was measured in accordance with the method and conditions described above. The arithmetic average value of the three large specimens, that is, the compression set of the elastic layer was 7%.

Here, as a polyurethane preparation component, polyester polyol (trade name “C-1000”, manufactured by Mitsui Takeda Chemical Co., Ltd., number average molecular weight (GPC) 1.2 × 10 ³ ) 48 parts by mass, and as a polyurethane preparation component methyl ethyl ketoxime ( 52 parts by mass (NCO / OH = 1.10) of isophorone diisocyanate (IPDI) (trade name “B-830N”, manufactured by Mitsui Takeda Chemical Co., Ltd.) blocked with a blocking agent) and silicone graft acrylic resin (trade name) “X-24-798A, X-22-8004 or X-24-8053”, all manufactured by Shin-Etsu Chemical Co., Ltd.) and an aminosilane coupling agent (trade name “KBP-40”, manufactured by Shin-Etsu Chemical Co., Ltd.) ) At a mass ratio shown in Table 1 and Table 2 to prepare a composition.

Next, a silicone primer (trade name “Primer No. 19”, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the surface of the elastic layer. The composition was applied to the surface of the elastic layer coated with the primer by spray coating, and heated at 150 ° C. for 60 minutes to form a 150 μm thick coat layer. In this way, each conductive roller was produced. When the volume resistivity (temperature 20 ° C., relative humidity 50%) of each of the produced conductive rollers was measured by the above method, it was 10 ³ to 10 ¹² Ω · cm, and the surface roughness Rz of the coating layer was The results measured by the method are shown in Table 1 and Table. The coat layer had a JIS A hardness substantially equal to the JIS A hardness of the elastic layer.

  In addition, using the composition used to form the coating layers in the conductive rollers of Examples 1 to 8 and Comparative Examples 1 to 9, three specimens each having a flat plate-like shape having the above dimensions were prepared. . Using this large test piece, the compression set of this large test piece was measured according to the method and conditions described above, and the arithmetic average value of the three large test pieces was determined as the compression set of the coating layer of each conductive roller. did. The results are shown in Tables 1 and 2.

  A thin film corresponding to the coating layer of each conductive roller prepared in Examples 1 to 8 and Comparative Examples 1 to 9 was prepared on a metal plate in the same manner as each conductive roller (thickness 2.0 mm), and obtained. The obtained thin film was cut into about 5 mm square, and this was used as a sample for solvent extraction. The total mass of the test piece was 5 g. This test piece was put into 300 mL of xylene, and xylene was refluxed for 6 hours using a Soxhlet extractor. After cooling this xylene to about room temperature, each component extracted into xylene was quantified by liquid chromatography, and the total concentration of the extracted components relative to the total mass of the test piece was calculated. The results are shown in Tables 1 and 2.

  Next, four conductive rollers of each of Examples 1 to 8 and Comparative Examples 1 to 9 were prepared, and the electrophotographic printer shown in FIG. 3 (trade name: “MICROLINE 1032PS” manufactured by Oki Data Corporation, The developing rollers 24B, 24C, 24M, and 24Y are arranged at a resolution of 1200 dpi. Note that the developer and blade attached to the electrophotographic printer were used as the developer and the developer regulating member.

  Using this electrophotographic printer, continuous printing evaluation, photoconductor contamination evaluation, printing density evaluation, and crack evaluation are performed by the following methods. As a comprehensive evaluation, at least one of these evaluations is evaluated as “×”. In some cases, it was determined that the conductive roller could not be used in an image forming apparatus.

(Continuous printing evaluation)
This electrophotographic printer printed 10,000 sheets in an environment of a temperature of 20 ° C. and a relative humidity of 50%. Thereafter, black solid-halftone dot-5% duty-white background printing was repeated twice, and then continuous printing evaluation was performed depending on whether blurring of the image occurred in the black solid print portion. If no image fading has occurred in the black solid print section, “◎” is indicated. If the image has a slight blur in the black solid print section, “◯” is indicated. Although it is faint, the case where the degree of fading is practically acceptable is indicated as “△”, and the case where the image fading is not practically acceptable in the black solid print portion is indicated as “x”. . The results are shown in Tables 1 and 2.

  Subsequently, continuous printing evaluation was performed in the same manner except that the environment at a temperature of 20 ° C. and a relative humidity of 50% was changed to a temperature of 50 ° C. and a relative humidity of 80%. The results are shown in Tables 1 and 2.

(Evaluation of contamination of photoconductor)
The electrophotographic printer printed 10,000 sheets in an environment of a temperature of 20 ° C. and a relative humidity of 50%. Then, after repeating black solid-halftone dot-5% duty-white background printing twice, whether or not horizontal stripes due to the smear of the photoconductor occur in the black solid print portion, and if horizontal stripes occur Evaluated the contamination of the photoconductor depending on whether or not the horizontal streak disappeared during printing. When no horizontal streaks occur in the black solid print section, “◎” indicates that the horizontal streaks occur in the black solid print section, but the horizontal streaks appear while three black solid dots, 5% duty, and white background printing are performed. The case where the horizontal stripe disappears is set as “◯”, and the horizontal stripe is generated in the black solid print portion, but the case where the horizontal stripe disappears while the black solid halftone dot−5% duty−white background printing is performed is set as “△”, A case where a horizontal streak occurred in the black solid print portion and the horizontal streak did not disappear even after 10 or more black solids, halftone dots, 5% duty, and white background printing was indicated as “x”. The results are shown in Tables 1 and 2.

  Subsequently, the contamination of the photoconductor was evaluated in the same manner except that the environment at a temperature of 20 ° C. and a relative humidity of 50% was changed to a temperature of 50 ° C. and a relative humidity of 90%. The results are shown in Tables 1 and 2.

(Print density evaluation)
The electrophotographic printer printed 10,000 sheets in an environment of a temperature of 20 ° C. and a relative humidity of 50%. Thereafter, the black solid-halftone dot-5% duty-white background printing was repeated twice, the Macbeth density of the printed black solid print portion was measured with a Macbeth densitometer, and the print density was evaluated based on the measured Macbeth density. If the Macbeth density of the black solid printing portion is less than 1.3, it can be determined that the printing is defective. The results are shown in Tables 1 and 2.

  Next, the print density was evaluated in the same manner except that the environment at a temperature of 20 ° C. and a relative humidity of 50% was changed to a temperature of 50 ° C. and a relative humidity of 90%. The results are shown in Tables 1 and 2.

(Crack evaluation)
Each conductive roller was printed on 10,000 sheets in the continuous print evaluation, then taken out from the electrophotographic printer, and the surface of the coating layer of each conductive roller was visually observed to crack the coating layer. The occurrence situation of was evaluated. A case where cracks did not occur was indicated as “◯”, and a slight crack was generated, but a case where there was no problem in practical use was indicated as “△”, and a case where cracks occurred so as to be unacceptable in practice. It was set as “x”. The results are shown in Tables 1 and 2.

FIG. 1 is a perspective view showing an example of a conductive roller. FIG. 2 is a schematic view showing an example of an image forming apparatus according to the present invention. FIG. 3 is a schematic view showing another example of the image forming apparatus according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive roller 2 Shaft body 3 Conductive elastic layer 4 Coat layer 10, 30 Image forming apparatus 11, 11B, 11C, 11M, 11Y Image carrier 12, 12B, 12C, 12M, 12Y Charging means 13, 13B, 13C, 13M, 13Y Exposure means 14, 14B, 14C, 14M, 14Y Transfer means 15 Fixing means 15a Fixing roller 15b Pressure roller 16 Recording member 17, 17B, 17C, 17M, 17Y Cleaning means 20, 20B, 20C, 20M, 20Y Development Means 21, 21B, 21C, 21M, 21Y Housing 22, 22B, 22C, 22M, 22Y Developer 23 Stirring means 24, 24B, 24C, 24M, 24Y Developer carrier 25, 25B, 25C, 25M, 25Y Developer Amount adjusting means 26 Attaching means 31 Cassette 32 Transfer conveyance belt 33 Support roller B, , M, Y development units

Claims (4)

A conductive elastic layer formed on the outer peripheral surface of the shaft body, and a coat layer formed on the outer peripheral surface of the conductive elastic layer,
The coat layer is formed by curing a composition containing 100 parts by mass of a polyurethane preparation component, 1 to 10 parts by mass of a silicone graft acrylic resin, and 1 to 10 parts by mass of a silane coupling agent having an amino group. A conductive roller characterized by that.   2. The conductive roller according to claim 1, wherein the coating layer has a total concentration of extracted components of 100 ppm or less when extracted with xylene as a solvent using a Soxhlet extractor for 6 hours.   3. The conductive roller according to claim 1, wherein the coating layer has a compression set of 1 to 10% under the conditions of a temperature of 125 ° C., a compression rate of 25%, and a compression time of 22 hours. An image forming apparatus comprising the conductive roller according to claim 1.

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