Patent ID: 8588658

Claim:
An image forming apparatus comprising: an image forming unit including a latent image carrier and a development device to develop a latent image formed on the latent image carrier with developer, the development device comprising: a developer carrier disposed facing the latent image carrier, to carry the developer to the latent image carrier by rotation; a discharge port through which the developer is discharged outside the development device; a discharge port detector to detect whether the discharge port is open; and a controller operatively connected to the development device and the discharge port detector for performing discharge of developer from the development device, wherein, in the discharge of developer, the controller determines whether to permit driving of the development device in a direction reverse to a normal direction in which the development device is driven in image formation or to terminate the discharge of developer based on detection results obtained by the discharge port detector, wherein the discharge port detector comprises a toner concentration detector for detecting a concentration of toner in the developer in the development device, and wherein the discharge port detector determines whether the discharge port is open or closed by comparing an output from the toner concentration detector with a predetermined threshold.