Patent ID: 8032058

Claim:
An electrophotographic image forming apparatus in which a developing cartridge for developing an electrostatic latent image formed on an electrophotographic photosensitive member is detachably mounted to a mounting portion, the electrophotographic image forming apparatus comprising: an opening portion through which the developing cartridge is passed when mounting the developing cartridge to the mounting portion and when detaching the developing cartridge from the mounting portion; an openable and closable member movable between an opening position at which the opening portion is opened and a closed position at which the opening portion is closed; a lock member which releasably locks the developing cartridge to the mounting portion to which the developing cartridge has been mounted; and a releasing member acting on the lock member to release the lock of the developing cartridge portion by the lock member, wherein, in releasing the lock by the releasing member, the openable and closable member is moved from the closed position to the opening position by a user, whereby the releasing member pushes the lock member so that the lock member rotates about a fulcrum and is separated from a locked portion of the developing cartridge, wherein the developing cartridge has a developing roller for supplying developer to the electrophotographic photosensitive member to develop an electrostatic latent image formed on the electrophotographic photosensitive member, a positioned portion provided coaxially with the developing roller to position the developing cartridge with respect to the mounting portion, and the locked portion engaged with the lock member when the developing cartridge is mounted to the mounting portion, wherein the locked portion is provided on a lower surface of the developing cartridge, when the developing cartridge is mounted to the mounting portion, and wherein the locked portion is provided on a downstream side of the developing roller in a mounting direction in which the developing cartridge is mounted to the mounting portion.