Image formation apparatus compensating the thickness variation of photosensitive body and method of compensating development mass per area

摘要

PURPOSE: An image forming apparatus for compensating a variation in a film thickness of a photosensitive drum and a method of compensating developing quantity are provided to inform a user of the time of replacing the photosensitive drum and control a developing device to prevent deterioration of picture quality. CONSTITUTION: An image forming apparatus includes a photosensitive drum(71) for forming an electrostatic latent image, a charging roller(72) for charging the photosensitive drum, and a developing roller(74) for developing the electrostatic latent image. The image forming apparatus further includes a measurer(79) for measuring charge current flowing from the charging roller into the photosensitive drum, a comparator(61) for comparing the charge current with reference current, and a controller(67) for controlling a developing roller control parameter to compensate a variation in a film thickness of the photosensitive drum according to the output of the comparator.