Patent ID: 8126377

Claim:
A developer cartridge comprising: a housing configured to accommodate developer; a rotation shaft that is rotatably supported by the housing and passes across an inside of the housing; a supply opening that is formed in a wall of the housing opposite the rotation shaft in a diameter direction and is configured to supply the developer to an outside of the housing; a return opening that is formed in a wall of the housing at a position displaced from the supply opening in an axial direction of the rotation shaft and is configured to return the developer to the inside of the housing; a first agitation blade that is supported by the rotation shaft and is configured to pass through a position opposite the return opening along an inner surface of the housing by rotation of the rotation shaft; and a second agitation blade that is supported by the rotation shaft and is configured to pass through a position opposite the supply opening along an inner surface of the housing by the rotation of the rotation shaft, wherein the first agitation blade is configured to pass through the position opposite the return opening from above to below the position opposite the return opening, the position opposite the return opening being between the return opening and the rotation shaft.