DEVELOPING CARTRIDGE, IMAGE FORMING APPARATUS, AND METHOD OF MOUNTING/SEPARATING DEVELOPING CARTRIDGE ON/FROM IMAGE FORMING APPARATUS

An image forming apparatus having a developing cartridge includes a lower main body, and a developing cartridge installed in the lower main body and including a photosensitive medium. An upper main body may be separably installed on an upper side of the lower main body and includes an upper pressing member to press the developing cartridge downward. A lower pressing member, installed in the lower main body, is positioned to press the developing cartridge upward. In the case where a rotation axis of the photosensitive medium of the developing cartridge is set as a rotation center, a moment of force is applied to the developing cartridge by the upper pressing member and an opposing moment of force being is applied to the developing cartridge by the lower pressing member in the opposite direction.