Patent ID: 8750753

Claim:
A process unit comprising: a photosensitive member having an axis extending in an axial direction and a surface; a developing unit having a developing agent bearing member for bearing a developing agent to be supplied to the surface of the photosensitive member; a developer cartridge including: a casing defining an internal space for accommodating the developing agent, and a pressed portion provided at the casing and configured to be pressed by an external force, the developer cartridge being mountable on or detachable from the developing unit in a first direction, and further configured to be pressed in a second direction different from the first direction upon application of pressure to the pressed portion by the external force, the second direction being coincident with a direction of pressing the developing agent bearing member against the surface of the photosensitive member; a guide portion positioned on one side in the axial direction and shiftable between a first posture for guiding the developer cartridge to move relative to the developing unit in the first direction, and a second posture for guiding the developer cartridge to move relative to the developing unit in the second direction; and an operation portion configured to be operated to selectively shift the guide portion to one of the first posture and the second posture, wherein the casing is formed with an opening for supplying the developing agent accommodated in the internal space to the developing unit, wherein the developer cartridge further comprises a shutter movable between an open position for opening and a closed position for closing the opening, wherein the process unit further comprising a drive mechanism configured to move the shutter to the open position from the closed position when the guide portion is shifted to the second posture from the first posture in association with operation of the operation portion and to move the shutter to the closed position from the open position when the guide portion is shifted to the first posture from the second posture in association with operation of the operation portion.