Patent ID: 6958471
Filing Date: 2005-10-25
Classification: H04N

Abstract:
1. 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: effecting a control to position the movable light beam within the tolerable range of a first passage target position by adjusting the angle of the mirror surface of the galvano-mirror, and measuring a first circuit offset in a detection circuit for an output of the sensor at a time when emission of the movable light beam is stopped; emitting the movable light beam once again, effecting a control to position the movable light beam at the first passage target position with the first circuit offset being subtracted, and storing a first output value from the sensor at a time when the movable light beam is controlled and set at the first passage target position; effecting a control to position the movable light beam within the tolerable range of a second passage target position by adjusting the angle of the mirror surface of the galvano-mirror, and measuring a second circuit offset in the detection circuit for the output of the sensor at a time when emission of the movable light beam is stopped; emitting the movable light beam once again, effecting a control to position the movable light beam at the second passage target position with the second circuit offset being subtracted, and storing a second output value from the sensor at a time when the movable light beam is controlled and set at the second passage target position; and controlling the angle of the mirror surface of the galvano-mirror such that a difference between a third output value from the sensor at a time when the stationary light beam passes through the light-receiving surface of the sensor and a fourth output value from the sensor at a time when the movable light beam passes through the light-receiving surface of the sensor coincides with a difference between the first output value and the second output value.