Developing device for an image forming apparatus

Abstract

A developing device for an image forming apparatus of the present invention includes an image carrier performing endless movement while carrying a developer in the form of a layer thereon, and a regulating member for regulating the thickness of the layer Toner stored in the developing device is covered with an additive whose particle size is less than 2 μm. The regulating member is implemented as a doctor roller having a surface roughness Rz equal to or greater than the above particle size, but smaller than 2 μm. The doctor roller is pressed against a developing roller or developer carrier by a preselected pressure, forming a nip for development The developing device reduces irregular development ascribable to impurities caught at a regulating position assigned to the doctor roller more than a conventional developing device using a doctor blade as a regulating member. In addition, the developing device obviates irregular development in the form of fine stripes ascribable to stripe-like irregularities formed in the developer layer existing on the developing roller.

Dependencies are inferred from the claim text.