Patent ID: 8019258

Claim:
A developing apparatus comprising: a developer bearing member configured to bear a developer for developing an electrostatic image formed on an image bearing member; and a developer amount regulating device configured to regulate an amount of the developer carried by the developer bearing member, wherein the developer amount regulating device includes: a flexible developer amount regulating member including a pressing portion configured to contact and press the developer bearing member; a holding member configured to hold the developer amount regulating member in a curvature shape in which the developer amount regulating member forms a convex shape toward the developer bearing member in a state that the developer amount regulating member is not in contact with the developer bearing member; a portion, disposed in the holding member, which an end face of each end of the developer amount regulating member in a shorter direction comes into contact with when the developer amount regulating member is pressed against the developer bearing member; and a supporting portion disposed in the holding member and configured to prevent the each end from spreading by contacting a surface where the pressing portion in the developer amount regulating member is provided, wherein the developer amount regulating member is held by the holding member by contact pressure of the surface where the pressing portion is provided against the when the developer amount regulating member is pressed against the developer bearing member; and a supporting portion disposed in the holding member and configured to prevent the each end from spreading by contacting a surface where the pressing portion in the developer amount regulating member is provided, wherein the developer amount regulating member is held by the holding member by contact pressure of the surface where the pressing portion is provided against the supporting portion due to a restoration force generated by the developer amount regulating member trying to revert from a bended shape, wherein the developer amount regulating device deforms the developer amount regulating member by pressing the developer amount regulating member against the developer bearing member so that pressure distribution includes two maximum values in a rotation direction of the developer bearing member in the pressing portion, and wherein the holding member includes a concave portion, the portion where the end face contacts is a bottom face of the concave portion, and the supporting portion is a side face of the concave portion.