Abstract: A developing apparatus of a toner delivery system by contacting a developer roller with an electrostatic latent image-carrying member eliminates a protective layer in the conventional concept from a surface of the developing roller, and provides a covering layer which is formed by adhering particles of toner or a material having electrical characteristics and mechanical characteristics equal to those of the toner on the surface of the developing roller. Those particles are adhered utilizing a surface tackiness of an elastomer layer itself which is a structural element of the developing roller.