Abstract: Disclosed is a method for cleaning the contact charger of an electrophotographic apparatus including a photosensitive (photoconductive) drum, developing means, transfer means and main motor, which comprises the steps of applying a charging voltage of a specified level to the contact charger to make the surface of the photosensitive drum keep a surface potential of a given level during rotation of the main motor, cutting off the charging voltage applied to the contact charger and developing voltage applied to the developing means after a specified time so as to transfer the toner of opposite polarity attached to the contact charger to the photosensitive drum, and applying a negative transfer voltage to the transfer means so as to transfer the toner of opposite polarity transferred to the photosensitive drum to a sheet of paper.

Abstract: An image forming apparatus includes detachable expendables such as a photosensitive drum, a toner cartridge, an ozone filter, etc. The image forming apparatus counts a number of papers being printed after replacing the expendable and stores a counting value as an amount of use in a nonvolatile memory, and prints out a status message including the amount of use, periodically or whenever the image forming apparatus is turned on. Further, the status message includes a predetermined test pattern for testing the printing status of the printer. In the light of the status message, the user may predict in advance the proper replacing time and cope with degradation of the images by checking the printing status from the test pattern at any time.