Patent ID: 7233758

Claim:
A developing device comprising: a rotatable developer carrying member for carrying a developer to develop an electrostatic image formed on an image bearing member with the developer; non-rotatable magnetic field generating means, disposed inside said developer carrying member, for magnetically attracting the developer on said developer carrying member; and a regulating member for regulating an amount of the developer carried on said developer carrying member, wherein said developer carrying member is provided with an elastic surface layer, and said developer carrying member is provided so that said elastic surface layer presses the developer carried on said developer carrying member against said image bearing member, and wherein the developer is an one component magnetic toner having an average circularity not less than 0.965, and an amount of the developer per unit area of the developer regulated by said regulating member is 5-14 g/m 2 , and an amount of electric charge thereof is 10-50 μC/g.