Patent ID: 8204410

Claim:
A developer cartridge comprising: a housing that is attachable to and detachable from a developing device and is configured to accommodate developer; and an agitator that is configured to agitate the developer accommodated in the housing and supply the developer to the developing device through a supply opening formed in the housing, wherein the agitator comprises: a rotation shaft that is rotatably supported by the housing; a support plate that extends from the rotation shaft to one side in a diameter direction of the rotation shaft; a delivery agitation blade that is supported by the support plate and is configured to pass through a position opposing the supply opening along an inner surface of the housing by rotation of the rotation shaft, the delivery agitation blade comprising a first end portion, and an entire width of the first end portion being supported by a distal end portion of the support plate; and an oblique agitation blade that is erected from a surface of the support plate and is oblique to the rotation shaft in order to move the developer in an axial direction of the rotation shaft toward the supply opening, wherein the delivery agitation blade comprises a concave portion that is configured to be concave to a backward side in a rotation direction of the rotation shaft during agitation of the delivery agitation blade, wherein the delivery agitation blade comprises a flexible sheet that is configured to make sliding contact with an inner surface of the housing in a bent state, wherein the delivery agitation blade further comprises: a second end portion; and a slit for dividing the second end portion into plural parts, and wherein when the second end portion makes sliding contact with the inner surface of the housing, the concave portion is formed by different delay amounts between ends of at least both sides of the divided second end portions in the rotation direction.