PURPOSE:To constantly insure a stable print quality by automatically controlling an electrophotographic process based on information read by an information reading means which reads the information concerning service life of a photosensitive body recorded on an information recording medium. CONSTITUTION:A conditional value concerning the control of the electrophotographic process to compensate deterioration of the print quality arising with deterioration of sensitivity of the photosensitive drum is set beforehand to a process conditional value table of ROM32 according to the printed number of pages as the information concerning the service life of the photosensitive drum. The number of printed pages is counted and stored by a memory card 51, and the conditional value responding to present printed number of pages is read out from the table at the start of printing, and the electrophotographic process is automatically controlled based on this conditional value. Therefore, the processing in the electrophotographic process is always automatically controlled to compensate the deterioration of the printed quality arising with the deterioration of the sensitivity of the photosensitive drum. Thus, the stable printed quality can be always secured.