Patent ID: 7606506

Claim:
An image forming apparatus, comprising: a development unit in which toner is accommodated, the development unit including an agitator for agitating the toner and, a development roller to which a predetermined development bias voltage is applied, the development unit performing development by making the toner adhered to the development roller, to which the predetermined development bias voltage is applied, attach to a latent image formed on a surface of an image carrier; a driver for driving the agitator; a toner supply portion for supplying toner to the development unit; a time counter for counting a drive time of the driver while the development unit is not performing development; a drive-time-storage controller that, each time the time counter counts the drive time, stores the drive time on an accumulative basis in an electrically rewritable nonvolatile memory; a toner discharge portion for discharging out of the development unit the toner accommodated therein; and a toner supply/discharge controller that performs toner supply/discharge control such that, when the drive time stored in the nonvolatile memory reaches or exceeds a predetermined period, the toner supply portion supplies a predetermined amount of toner to the development unit and that the toner discharge portion discharges the predetermined amount of toner out of the development unit, wherein the drive-time-storage controller resets the drive time stored in the nonvolatile memory after the toner supply/discharge controller performs the toner supply/discharge control.