Patent ID: 8547606

Claim:
An optical scanning apparatus comprising: an optical scanning unit including a swing mirror deflecting an optical beam and driving unit, the swing mirror being supported by a torsional vibration system having a first natural frequency and a second natural frequency that is a double of the first natural frequency, and the driving unit being configured to apply a swing torque having the first natural frequency and the second natural frequency to the torsional vibration system; an optical beam detection unit configured to detect passage of an optical beam deflected by the swing mirror at two locations in a non-image region, and output track information indicating a track of the swing mirror; a track control unit configured to, based on a difference between the track indicated by the track information detected by the optical beam detection unit and a predetermined target track, adjust the swing torque such that the track of the swing mirror approaches the target track, thereby performing feedback control; a calculation unit configured to sequentially switch target tracks of scanning in a forward direction and a backward direction, the phases of the second natural frequency of the target tracks being mutually reversed, perform the feedback control by the track control unit for each scanning in the forward direction and the backward direction, and calculate an amount of offset compensation based on the difference between the predetermined target track and the track detected by the optical beam detection unit for each scanning in the forward direction and the backward direction; and an offset compensation unit configured to reflect the amount of offset compensation in the feedback control.