Patent ID: 8452208

Claim:
An electrophotographic image forming apparatus for forming an image on a recording material, said electrophotographic image forming apparatus comprising: an electrophotographic photosensitive drum; a developing cartridge including: a developing roller for developing an electrostatic latent image formed on said electrophotographic photosensitive drum, a developer accommodating portion for accommodating a developer to be used by said developing roller to develop the electrostatic latent image, and a developing roller shutter movable between a protecting position for covering a part of a peripheral surface of said developing roller and a retracted position, retracted from the protecting position, for exposing the part of the peripheral surface of said developing roller, wherein said developing cartridge is detachably mountable to a main assembly of the apparatus; a cartridge supporting member movable, while detachably mounting said developing cartridge and fixedly supporting said electrophotographic photosensitive drum, between an inside position that is inside of said main assembly of the apparatus to mount said developing cartridge to said main assembly of the apparatus, and an outside position that is outside of said main assembly of the apparatus to remove said developing cartridge from said main assembly of the apparatus; a force receiving portion, provided on said developing cartridge, for receiving a force for moving said developing roller shutter from the protecting position to the retracted position; and a force applying portion provided in said main assembly of the apparatus, wherein, when said cartridge supporting member is moved from the outside position to the inside position, said force receiving portion contacts to said force applying portion to move said cartridge supporting member from the outside position to the inside position, in interrelation with which said force receiving portion contacted to said force applying portion receives the force from said force applying portion, thus moving said developing roller shutter from the protecting position to the retracted position, and wherein said cartridge supporting member detachably supports a plurality of such developing cartridges, and when said cartridge supporting member is moved from the outside position to the inside position, said force receiving portions of said developing cartridges are contacted to said force applying portions at different points of time.