Patent ID: 7945196

Claim:
A developing device comprising: a developer supporting member having an elastic layer and a surface layer covering the elastic layer; and a supply member contacting with the developer supporting member for supplying developer to the developer supporting member, said surface layer being formed of a mixture containing at least an acrylic resin and a polyether type urethane resin, said developer supporting member and said supply member being configured so that the following equations are satisfied: 20≦A1≦80 0.6≦D≦2.0 45+0.1 ×A 1× D≦F×N≦ 65 where A 1 is a weight ratio (%) of the acrylic resin relative to a total weight of the acrylic resin and the polyether type urethane resin, D is a thickness of the surface layer, F is an Asker F hardness (degree) of a surface of the supply member, and N is an overlap amount (mm) representing a biting amount of the supply member relative to the developer supporting member.