Patent ID: 7005631

Claim:
A beam position adjusting method for an optical scanning device using a galvano-mirror capable of altering an angle of a mirror surface by a drive control, and using a sensor that detects passage positions of a stationary light beam whose scanning position is fixed and a movable light beam whose scanning position is varied by adjusting the angle of the mirror surface of the galvano-mirror, the method comprising: detecting a passage position of the stationary light beam on a light-receiving surface of the sensor; determining a passage position of the movable light beam on the light-receiving surface of the sensor, relative to the detected passage position of the stationary light beam; effecting a control to move the movable light beam to the determined passage position by adjusting the angle of the mirror surface of the galvano-mirror; checking, upon completion of the control to move the movable light beam to the determined passage position, whether the movable light beam has moved to the determined passage position; and detecting once again the passage position of the stationary light beam, when the movable light beam has failed to move to the determined passage position.