A process cartridge usable with an image forming apparatus includes a developing member, a photosensitive medium to face the developing member, a pair of supporting plates to rotatably support the developing member and the photosensitive medium; a center moving member rotatably disposed on the supporting plate, the center moving member having a first position in which the photosensitive medium contacts the developing member and a second position in which the photosensitive medium is spaced apart from the developing member; and a separation restraining member formed so that when the center moving member locates at the second position, the separation restraining member restrains the center moving member from moving from the second position.