Patent ID: 7446921
Filing Date: 2008-11-04
Classification: G02B,G06K,H04N

Abstract:
1. An image forming apparatus having an exposure unit and a light source, the exposure unit including an oscillation system and a drive unit, the oscillation system including a first oscillating member having a reflective element, and a second oscillating member connected to the first oscillating member by a torsion member, the second oscillating member having a permanent magnet, and the drive unit arranged to apply a torque to the permanent magnet, thereby transmitting a drive force to the first and second oscillating members so that the first and second oscillating members oscillate about an axis of the torsion member, and the light source arranged to emit a light beam, wherein the exposure unit scans the light beam emitted to the reflective element of the first oscillating member when activated, the image forming apparatus comprising: an oscillation detecting unit arranged to detect a oscillation state of the oscillation system; a drive control unit configured to control oscillation of the oscillation system such that the oscillation system oscillates in a balanced steady state by adjusting the drive force caused by the drive unit with one or more drive control parameter values, said drive control parameter values being determined on the basis of the detection result obtained by the oscillation detecting unit; a parameter storing unit arranged to store the drive control parameter values when the balanced steady state is detected by the oscillation detecting unit; and a parameter resetting unit configured to set the drive control parameter values stored in the parameter storing unit to the drive control unit when the exposure unit is next activated.