Patent ID: 7512351

Claim:
An image forming apparatus, comprising: an image carrying body; a latent image forming unit to form an electrostatic latent image on the image carrying body; a developing unit to form a toner image by developing the electrostatic latent image on the image carrying body, the developing unit including a developing agent carrying body to carry a developing agent in a development region, and a direct-current power supply and an alternating-current power supply which apply a developing bias voltage to the developing agent carrying body, the developing bias voltage being generated by superimposing a direct-current voltage on an alternating voltage; a printing rate detecting unit to detect a printing rate; and a control unit to control the alternating-current power supply, wherein the control unit performs control to change an output from the alternating current power supply during a development process in an image forming process, based on a detection result of the printing rate detecting unit.