DEVELOPER AND IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To maintain a preferable state of a photoreceptor surface even in long-term use without increasing the scale of an apparatus and to stably obtain a color image with high picture quality. SOLUTION: The developer is used in an image forming apparatus having steps of forming a color image by using a single photoreceptor and of removing a residual toner on the photoreceptor after a transferring step with a cleaning blade, wherein the developer comprises a black toner having a circularity of 0.96 or less and a color toner having a circularity of 0.96 or more, both of the black toner and the color toner contain externally added inorganic fine particles containing Si and inorganic fine particles containing Ti. The amounts of the inorganic fine particles externally added to the black toner and the color toner satisfy formulae (1) and (2), wherein Si(C), Ti(C), Si(Bk) and Ti(Bk) are explained in the specification. COPYRIGHT: (C)2008,JPO&INPIT