Abstract: Provided are a developing unit alleviating fogging occurrence and an electrophotographic image forming apparatus providing images over long periods. The developing unit includes at least a toner of (1) and a developing roller of (2). (1) When a displacement amount when a load is applied at Y° C. and 9.8×10?5 N/sec to 2.94×10?4 N is X2(Y), a displacement amount when the toner is left to stand for 0.1 second is X3(Y), a displacement amount when the load is reduced at 9.8×10?5 N/sec to 0N is X4(Y), and percentage of (X3(Y)?X4(Y)) to X3(Y) is Z(Y), 40?Z(25)?80 and 10?Z(50)?55 are satisfied; when a gradient from the origin to the maximum load in the load-displacement curve at 25° C. is R(25), 0.49×10?3?R(25)?1.70×10?3 is satisfied; the toner has glass transition temperature TgA (40° C.-60° C.) and maximum endothermic peak temperature P1 (70° C.-110° C.), 15° C.?(P1?TgA)?70° C. is satisfied.

Abstract: A high-quality developing member which excels in filming resistance and excels in leak resistance despite high electroconductivity is provided. The developing member includes an electroconductive substrate, an elastic layer formed on the substrate, and a surface layer which covers a surface of the elastic layer. The surface layer includes a first resin which has, between two adjacent urethane linkages, a structure represented by the structural formula (1) and one or both of structures selected from the group consisting of a structure represented by the structural formula (2) and a structure represented by the structural formula (3), a second resin which has a structure represented by the structural formula (4) and one or both of structures selected from the group consisting of a structure represented by the structural formula (5) and a structure represented by the structural formula (6), and an electronically conductive filler.

Abstract: A developing roller includes: a mandrel; an elastic layer provided for an outer periphery of the mandrel, the elastic layer including an addition-curing silicone rubber; and a surface layer provided for an outer periphery of the elastic layer, in which: the elastic layer includes a compound represented by the following formula (1); when the content of such a compound that n in the formula (1) represents an integer of 3 to 12 in the elastic layer is represented by P1, and the content of such a compound that n in the formula (1) represents an integer of 13 to 20 in the elastic layer is represented by P2, P1+P2 is 5,000 ppm by mass to 12,000 ppm by mass; and P1 is 1,500 ppm by mass to 6,000 ppm by mass (In the formula (1), n represents an integer of 3 to 20):

Abstract: A developing roller includes: a mandrel; an elastic layer provided for an outer periphery of the mandrel, the elastic layer including an addition-curing silicone rubber; and a surface layer provided for an outer periphery of the elastic layer, in which: the elastic layer includes a compound represented by the following formula (1); when the content of such a compound that n in the formula (1) represents an integer of 3 to 12 in the elastic layer is represented by P1, and the content of such a compound that n in the formula (1) represents an integer of 13 to 20 in the elastic layer is represented by P2, P1+P2 is 5,000 ppm by mass to 12,000 ppm by mass; and P1 is 1,500 ppm by mass to 6,000 ppm by mass (In the formula (1), n represents an integer of 3 to 20):

Abstract: Provided are a developing unit alleviating fogging occurrence and an electrophotographic image forming apparatus providing images over long periods. The developing unit comprises at least toner (1), developing roller (2). (1) when a displacement amount when a load is applied at Y° C. and 9.8×10?5 N/sec to 2.94×10?4 N is X2(Y), a displacement amount when the toner is left to stand for 0.1 second is X3(Y), a displacement amount when the load is reduced at 9.8×10?5 N/sec to ON is X4(Y), and percentage of (X3(Y)?X4(Y)) to X3(Y) is Z(Y), 40?Z(25)?80 and 10?Z(50)?55 are satisfied; when a gradient from the origin to the maximum load in the load-displacement curve at 25° C. is R(25), 0.49×10?3?R(25)?1.70×10?3 is satisfied; the toner has glass transition temperature TgA (40° C.-60° C.) and maximum endothermic peak temperature P1 (70° C.-110° C.), 15° C.?(P1?TgA)?70° C. is satisfied. (2) developing roller comprises a surface layer containing a urethane resin having structure (a), and one or both structures (b)-(c).

Abstract: A high-quality developing member which excels in filming resistance and excels in leak resistance despite high electroconductivity is provided. The developing member includes an electroconductive substrate, an elastic layer formed on the substrate, and a surface layer which covers a surface of the elastic layer. The surface layer includes a first resin which has, between two adjacent urethane linkages, a structure represented by the structural formula (1) and one or both of structures selected from the group consisting of a structure represented by the structural formula (2) and a structure represented by the structural formula (3), a second resin which has a structure represented by the structural formula (4) and one or both of structures selected from the group consisting of a structure represented by the structural formula (5) and a structure represented by the structural formula (6), and an electronically conductive filler.

Abstract: Provided is a developing member capable of suppressing a variation in resistance even when exposed to a high-temperature, high-humidity environment for a long time period. The developing member comprises: a mandrel; an electro-conductive elastic layer provided on a periphery of the mandrel; and a surface layer provided on a surface of the elastic layer, wherein: the elastic layer contains a dimethyl silicone rubber and carbon black; and an amount ? of a hydrogen atom bound to a silicon atom of the dimethyl silicone rubber, and an amount ? of a hydrogen atom of methyl groups bound to a silicon atom of the dimethyl silicone rubber, satisfy a relationship of 2.5×10?5??/??1.0×10?4.

Abstract: Provided is a developing roller including elastic layer and resin layer adhered to each other and having an appropriately resistance, thereby suppressing fogging. The developing member comprises a mandrel; an elastic layer; and a resin layer, wherein: the resin layer comprises polyurethane resin obtained by isocyanate and polyol; and the elastic layer includes cured silicone rubber composition comprising (a)-(d): (a) organopolysiloxane having two or more alkenyl groups bonded to silicon atom and having methyl group as a group other than the alkenyl bonded to the silicon; (b) organopolysiloxane having three or more hydrogen atoms bonded to silicon atom and having methyl group as a group bonded to the silicon; (c) carbon black; (d) organopolysiloxane represented by formula (1) and having Mw of 18,000-110,000 and Mw/Mn of 1.0-2.0 (R1 represents alkenyl group, R2 represents functional group reacting with isocyanate, and n represents an integer of 1 or more).

Abstract: Provided is a developing member capable of suppressing a variation in resistance even when exposed to a high-temperature, high-humidity environment for a long time period. The developing member comprises: a mandrel; an electro-conductive elastic layer provided on a periphery of the mandrel; and a surface layer provided on a surface of the elastic layer, wherein: the elastic layer contains a dimethyl silicone rubber and carbon black; and an amount ? of a hydrogen atom bound to a silicon atom of the dimethyl silicone rubber, and an amount ? of a hydrogen atom of methyl groups bound to a silicon atom of the dimethyl silicone rubber, satisfy a relationship of 2.5×10?5??/??1.0×10?4.

Abstract: Provided is an electro-conductive member showing small unevenness of the residual state of charge. The electro-conductive member is an electro-conductive member, comprising: a substrate whose surface is electro-conductive; and an electro-conductive elastic layer provided on the substrate, wherein the elastic layer is obtained by curing a mixture containing the following (A) to (D): (A) an organopolysiloxane having at least two vinyl groups bonded to a silicon atom; (B) an organopolysiloxane represented by the following chemical structural formula (1); (C) a hydrogen polysiloxane having at least two hydrosilyl groups; and (D) carbon black (l, m, and n in the chemical structural formula (1) each independently represent a positive integer).

Abstract: There is provided a process for producing a regenerated elastic roller which can be again used for the formation of high-quality electrophotographic images by sufficiently relaxing a compression set of the elastic roller having the compression set caused in an elastic layer in usage. The process for producing a regenerated elastic roller includes a step of heating an elastic roller having a conductive mandrel and an elastic layer and having a compression set caused in the elastic layer, in a cylindrical mold to thermally expand the elastic layer and to cause a surface of the elastic roller to contact an inner wall of the cylindrical mold.

Abstract: An object of the present invention is to provide a production process of a roller for an electrophotography, having a surface layer the electric resistance of which has been controlled by corona discharge treatment while keeping any pinholes from coming about on the surface. A production process of a roller for an electrophotography, said roller comprising a conductive mandrel and a conductive surface layer comprising a resin and carbon black dispersed in the resin, the process having the following steps (1) to (3): (1) forming a resin layer comprising a resin and carbon black dispersed therein on the circumference of the conductive mandel; (2) attaching silica particles on the surface of the resin layer; and (3) subjecting corona discharge treatment to the surface of the resin layer on which the silica particles are attached.

Abstract: There is provided a process for producing a regenerated elastic roller which can be again used for the formation of high-quality electrophotographic images by sufficiently relaxing a compression set of the elastic roller having the compression set caused in an elastic layer in usage. The process for producing a regenerated elastic roller includes a step of heating an elastic roller having a conductive mandrel and an elastic layer and having a compression set caused in the elastic layer, in a cylindrical mold to thermally expand the elastic layer and to cause a surface of the elastic roller to contact an inner wall of the cylindrical mold.

Abstract: An object of the present invention is to provide a production process of a roller for an electrophotography, having a surface layer the electric resistance of which has been controlled by corona discharge treatment while keeping any pinholes from coming about on the surface. A production process of a roller for an electrophotography, said roller comprising a conductive mandrel and a conductive surface layer comprising a resin and carbon black dispersed in the resin, the process having the following steps (1) to (3): (1) forming a resin layer comprising a resin and carbon black dispersed therein on the circumference of the conductive mandel; (2) attaching silica particles on the surface of the resin layer; and (3) subjecting corona discharge treatment to the surface of the resin layer on which the silica particles are attached.