Developing apparatus featuring a developer carrying member with an elastic surface layer

摘要

A developing device includes 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 the developer carrying member, for magnetically attracting the developer on the developer carrying member; a regulating member for regulating an amount of the developer carried on the developer carrying member, wherein the developer carrying member is provided with a surface elastic layer, and the developer carrying member is press-contacted to the image bearing member, and wherein, the developer is a 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 the regulating member is 5-14 g/m², and an amount of electric charge thereof is 10-50 muC/g.