Patent ID: 7623815

Claim:
A developing device comprising: a casing; a developing roller held by the casing and carrying a developing agent; and a layer-thickness regulating blade for regulating a layer thickness of the developing agent carried on the developing roller, wherein the layer-thickness regulating blade includes: a support member that is formed in a rectangular shape extending in an axial direction of the developing roller, and is attached to the casing; a leaf-spring member that is supported by the support member and extends toward the developing roller from the support member; and an abutment portion provided at a tip end portion of the leaf-spring member and abutting against the developing roller, wherein the developing device includes: a blade fixing portion that is provided in the casing, is opposed to each longitudinal end portion of the support member, and fixes the corresponding longitudinal end portion of the support member thus opposed; and an elastic member arranged between the blade fixing portions, interposed between the casing and the support member, and protruding to a side of the disposed position of the developing roller from an opposed surface of the blade fixing portion to the support member in the state where the developing roller is not held by the casing; wherein in a state where the developing roller is held by the casing, the abutment portion abuts against the developing roller at a uniform pressure in the axial direction of the developing roller, and in the state where the developing roller is not held by the casing, the support member is attached in the casing so that the layer-thickness regulating blade is bent toward a disposed position of the developing roller.