An electroconductive elastic body includes: a cross-linked product of a first ionic electro-conductive rubber, a cross-linked product of a second ionic electro-conductive rubber, and at least one of a fatty acid and a fatty acid metal salt; wherein the electroconductive elastic body has a matrix that includes the cross-linked product of the first ionic electro-conductive rubber, and a domain that includes the cross-linked product of the second ionic electro-conductive rubber; the cross-linked product of the second ionic electro-conductive rubber includes a polyether skeleton; an electrical resistance of the domain is lower than an electrical resistance of the matrix; in a waveform separation profile of the elastic body as obtained by a small-angle X-ray scattering method, A2 and A1 satisfy a relationship expressed by the following expression (1):
0.005≤(A2×C2/A1×C1)≤0.030  (1).

To provide a conductive roll for an electrophotographic apparatus that includes a conductive rubber elastic body layer having a lower hardness and lower settling properties than a conventional conductive rubber elastic body layer.

A conductive roll 10 for an electrophotographic apparatus includes a shaft body 12, and a conductive rubber elastic body layer 14 provided on the outer periphery of the shaft body 12, the conductive rubber elastic body layer 14 containing polar rubber, non-polar rubber, and a dispersing agent, wherein the polar rubber is at least one of nitrile rubber, hydrin rubber, and chloroprene rubber, wherein the non-polar rubber is at least one of isoprene rubber, hydrogenated isoprene rubber, and natural rubber, and wherein the dispersing agent is at least one of a polymer containing a block made of a nitrile rubber component and a block made of an isoprene rubber component, modified natural rubber, and modified isoprene rubber.

Provided is an electrophotographic member including an electro-conductive substrate and a surface layer on the substrate. The surface layer contains a urethane resin and a first polymer having a specific nitrogen-containing structure. The urethane resin has a structure derived from a second polymer containing a fluorine atom or a structure derived from a third polymer containing a fluorine atom and a silicon atom. The surface layer contains nitrogen atoms derived from the nitrogen-containing structure at a specific ratio in a region from the outer surface of the surface layer to a depth of 300 nm, and the atomic ratios of nitrogen atoms, fluorine atoms, and silicon atoms in a region from a depth of 100 nm from the outer surface of the surface layer to a depth of 300 nm and a region from the outer surface to a depth of 10 nm have specific relationships.

A conductive roller includes a support member, an elastic layer disposed on an outer peripheral surface of the support member, and a surface layer disposed on an outer peripheral surface of the elastic layer. The elastic layer includes a cylindrical elastic foam and a conductive covering layer covering an exposed surface of the elastic foam and has a volume resistance value of 10.sup.5Ω or less at an applied voltage of 10 V. The elastic foam has a conductive particle content of 1% by mass or less based on the total mass of the elastic foam.

A developing roll has a metal core, an elastic layer, and a surface layer, A value X is 65.6 N/mm.sup.3 or more and a value Y is 229 μm or more. The value X is P.sub.1/(D.sub.2×A) P.sub.2/(D.sub.2× A). P.sub.1 is the load to displace the roll by 100 μm when a metal probe is pressed against the roll. D.sub.1 is the displacement of the roll caused by the probe under the load P.sub.1. A is the area of the probe. P.sub.2 is the load to displace a material roll by 100 μm when the probe is pressed against the material roll with the core and the elastic layer and without the surface layer. D.sub.2 is the displacement of the material roll caused by the probe under the load P.sub.2. The value Y is the displacement of the developing roll when the probe pierces the surface layer.

An electrophotographic roller includes: a mandrel and an elastic layer on the mandrel, and having a crown shape in which a diameter decreases from a central position O in a longitudinal direction of the mandrel toward an end portion. When a position of the end portion in the longitudinal direction of the elastic layer is defined as X2, a position between the O and the X2 is defined as Xl, a distance between the O and the X1 is defined as L1, and a distance between the X1 and the X2 is defined as L2, L1=0.6×(L1+L2). When outer diameters of the electrophotographic roller at O, X1 and X2 are defined as Do, DX1 and DX2, respectively, and Z1=(Do−DX1)/2 and Z2=(DX1−DX2)/2 are defined, Z1, Z2, L1 and L2 satisfy (Z2/L2)<1.931×(Z1/L1).

An electrophotographic roller includes: a mandrel and an elastic layer on the mandrel, and having a crown shape in which a diameter decreases from a central position O in a longitudinal direction of the mandrel toward an end portion. When a position of the end portion in the longitudinal direction of the elastic layer is defined as X2, a position between the ) and the X2 is defined as X1, a distance between the O and the X1 is defined as L1, and a distance between the X1 and the X2 is defined as L2, L1=0.6×(L1+L2). When outer diameters of the electrophotographic roller at O, X1 and X2 are defined as Do, DX1 and DX2, respectively, and Z1=(Do−DX1)/2 and Z2=(DX1−DX2)/2 are defined, Z1, Z2, L1 and L2 satisfy (Z2/L2)<1.931×(Z1/L1).

A conductive roll includes a support member, an elastic layer disposed on an outer peripheral surface of the support member, a surface layer disposed on an outer peripheral surface of the elastic layer, and an intermediate layer disposed between the elastic layer and the surface layer, the intermediate layer having a Poisson ratio of 0.40 or less.

A developing device capable of stably collecting untransferred toner collected from the photoconductor drum to the developing roller to the feed roller and suppressing occurrence of development ghosts, and an image forming apparatus including the same are provided. A developing device has a developing roller facing a photoconductor drum, a feed roller, and a restriction blade. The feed roller forms a feed nip part with the developing roller by contacting with the circumferential surface of the developing roller, and collects toner from the developing roller while feeding the toner to the developing roller. The Asker-C hardness of the developing roller is in the range of 50 to 80, both inclusive, the width of the feed nip part is in the range of 0.2 to 1.5 mm, both inclusive, and a compressive load to be applied to the feed roller is in the range of 0.2 to 1.5N, both inclusive.

Provided is an electrophotographic electro-conductive member including a support having an electro-conductive outer surface, and an electro-conductive layer. The electro-conductive layer has a matrix containing a crosslinked product of a first rubber and domains containing a crosslinked product of a second rubber and an electron conductive agent. When measuring an impedance by applying alternating voltage between the outer surface of the support and a platinum electrode on an outer surface of the electro-conductive layer while changing a frequency, a slope at specific frequencies is −0.8 to −0.3 in a double logarithmic plot, and an impedance at specific frequency range is 1.0×10.sup.4Ω to 1.0×10.sup.11Ω. When measuring an impedance by applying alternating voltage between the outer surface of the support and a platinum electrode on an outer surface of the electrophotographic electro-conductive member while changing a frequency, an impedance at specific frequency range is 1.0×10.sup.5Ω to 1.0×10.sup.11Ω.