DEVELOPING UNIT AND IMAGE FORMING APPARATUS USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a developing unit that prevents, in a magnetic two- component developing system, the occurrence of base fog at both ends of an image area even in a low humidity environment and to provide an image forming apparatus. SOLUTION: A developing sleeve surface corresponding to the paper passage area of a photoreceptor drum is subjected to a blast process so that the relation ofα>βis established between the valueα(μm) of the Rz of the developing sleeve surface which corresponds to each of ranges extending specific distance inward from the corresponding ends of the maximum paper passage size and the valueβ(μm) of the Rz of the middle range extending between both the ranges.