Patent ID: 7499662

Claim:
A developing apparatus comprising: a case having a slit-shaped opening; a developer retainer which has a cylindrical shape, is supported by the case so as to be rotatable, and is arranged such that an axial direction thereof is along a longitudinal direction of the opening; a rectangular leaf spring, which has a sheet-like shape, is arranged in a longitudinal direction of the developer retainer and has one side end portion in a direction of a shorter side thereof that is fastened to the case; a pressing member which is arranged at the other side end portion in the direction of the shorter side of the leaf spring, for pressing the developer retainer by the leaf spring; a blade back seal which is interposed between the case and the leaf spring; a sponge sealing member which is interposed between the case and the developer retainer, and between the case and the leaf spring, wherein the blade back seal is in contact with the sponge sealing member between the one side end portion and the other side end portion of the leaf spring, and wherein the blade back seal and the sponge sealing member which are interposed between the case and the leaf spring, have the same thickness.