Image forming apparatus

摘要

An image forming apparatus includes a microcomputer. The number of image forming operation of a photosensitive drum is counted by a counter as a copy quantity, and data of the copy quantity is applied to the microcomputer. By referring to a copy quantity-voltage table, voltage setting data according to the copy quantity is applied by the microcomputer to a bias voltage source so that the bias voltage source applies a required bias voltage according to the voltage setting data to a conductive substrate of the photosensitive drum.