Patent ID: 8182405

Claim:
A developing roller for supplying a toner to a photosensitive member and developing an electrostatic latent image formed on the photosensitive member, the developing roller provided with a surface layer comprising carbon black and a polyurethane resin, wherein the polyurethane resin has at least one selected from the group consisting of the structures represented by the following chemical formulae (a) and (b): and at least one skeleton selected from the group consisting of a polybutadiene skeleton and a polyisoprene skeleton, wherein the surface layer comprises 18 parts by mass or more and 30 parts by mass or less of carbon black based on 100 parts by mass of the polyurethane resin, wherein a thickness of the surface layer is t, a surface of the surface layer is X, a depth at a position of t/4 from the surface of the surface layer is Y, and a depth at a position of t/2 from the surface of the surface layer is Z, wherein the following expressions (1) to (4) are simultaneously satisfied: 7.5≦EcX≦10.0 (1) 11.0≦EcZ≦14.0 (2) EcX≦EcY≦EcZ (3) 0.5≦UrcX≦2.0 (4), and wherein in expressions (1) to (3), EcX, EcY, and EcZ are ester group concentrations at positions X, Y, and Z, respectively, and in expression (4), UrcX is a urethane group concentration at position X.