Patent ID: 7747179

Claim:
An image forming apparatus comprising: a plurality of photosensitive units, each of the photosensitive units comprising a photosensitive medium; a plurality of developing devices, each of the developing devices comprising a developing roller and developer, the developing roller applying the developer to a corresponding photosensitive medium; a plurality of developing units each comprising one of the photosensitive units and one of the developing devices, wherein the developing device is removable from the developing unit; an integrated developing unit comprising a storage and at least two of the developing units, the integrated developing unit being individually replaceable; wherein the storage stores information regarding at least one of the photosensitive unit and the developing device of the integrated developing unit; a controller controlling the information stored in the storage; and a plurality of integrated developing units; wherein the controller reads and updates redefined information in the storage when a printing job is terminated, calculates and updates the amount of developer remaining in the developing device, counts the number of developing device replacements, and reports the necessity of replacing an integrated developing unit when the counted number of replacements reaches a predetermined threshold value.