Patent ID: 8805248

Claim:
A developer unit for an image forming apparatus to form an image on a recording sheet, comprising: a developer device comprising: a developer agent carrier configured to carry a developer agent on a surface thereof; and a developer agent supplier configured to supply the developer agent to the developer agent carrier; and a developer agent container configured to contain the developer agent to be supplied to the developer device and arranged in a lower position with respect to the developer device, the developer agent container comprising: a developer agent cartridge containing the developer; and an accommodating portion configured to detachably accommodate the developer agent cartridge at a position below the developer device, wherein the developer agent cartridge has a supply opening, through which the developer agent is to be supplied to the developer device, at a position opposite to the developer agent carrier relative to the developer agent supplier, and wherein the developer agent cartridge, which is detachable from the developer device, comprises an agitator arranged in a lower position with respect to the developer device and configured to rotate to sweep an inner surface of the developer agent container and to supply the developer agent upward through the supply opening.