Patent ID: 8509651

Claim:
An image forming apparatus comprising: an image forming portion including a plurality of image bearing members for carrying images and a plurality of developing devices for developing latent images formed on respective said image bearing members; a plurality of cartridges, detachably mountable to a main assembly of said apparatus, for supplying developers to respective said developing devices; a maintenance door for allowing access to said image forming portion for a maintenance operation; a plurality of first doors capable of opening and closing respective openings for insertion of said cartridges into the main assembly independently from each other, without access via said maintenance door; remainder detecting means for detecting information relating to amounts of the developers in respective said cartridges; locking means for locking said first doors; a controller capable of controlling said locking means to release a locking of a first door out of said first doors that corresponds to a cartridge out of said cartridges which requires exchange, on the basis of a detection result of said remainder detecting means; a moving mechanism for moving said released first door from a closed position to an opened position; and a second door capable of opening and closing to cover said first doors, wherein an image forming operation is capable of continuing irrespective of an opening and closing operation of said first doors and said second door, and said controller controls said locking means so that when an operator opens said second door, only selected ones of said first doors, that are required to be open for an exchange of the respective cartridges, are opened.