Patent ID: 7953346

Claim:
An image forming apparatus comprising: a lower main body of the image forming apparatus; a developing cartridge installed in the lower main body, and comprising a photosensitive medium; an upper main body of the image forming apparatus installed on an upper side of the lower main body, and comprising an upper pressing member to press the developing cartridge downward; and a lower pressing member, installed in the lower main body, to press the developing cartridge upward; wherein a moment of force being applied'to the developing cartridge by the upper pressing member about a rotation axis of the photosensitive medium and a moment of force being applied to the developing cartridge by the lower pressing member about a rotation axis of the photosensitive medium act in opposite directions to each other, wherein the developing cartridge is rotatably installed with respect to the lower main body and wherein when the photosensitive medium starts its rotation, the developing cartridge is rotated with respect to the lower main body, thereby shaking the toner and preventing the toner from becoming hardened.