Developing unit having developing roller with restraining blade

摘要

A developing unit of the present invention includes a case which accommodates toner containing pigment, a developing roller, and a supply roller formed of an elastic material arranged to be pressed against a surface of the developing roller in such a manner as to supply toner to the surface of the developing roller. A sealing member is disposed on the side ends of the developing roller and supply roller so as to prevent leakage to the outside portion of the case. A blade at least longer than the developing roller restrains the quantity of toner on the developing roller. The blade has a radius of curvature between 30 mu m and 150 mu m.