OPTICAL SCANNER AND IMAGE FORMING APPARATUS

摘要

PROBLEM TO BE SOLVED: To obtain a highly precise image output without causing any color shift and magnification error by calculating the variation in a scanning state with a beam luminous flux due to the temperature variation or the like by arranging a plurality of laser beam detectors having an angle at the end sides of adjacent light receiving parts at outside of the image region of a plane to be scanned. SOLUTION: The optical scanner comprises: a laser beam detector 1 composed of a light receiving part a having an end side parallel to a subscanning direction and a light receiving part b having an end side non-parallel (angleθ) to the subscanning direction; and a laser beam detector 2 composed of a light receiving part a' having an end side parallel to the subscanning direction. The optical scanner is so composed that the magnification error due to a main scanning is derived from the difference in the scanning time between the light receiving part a and the light receiving part a' and at the same time the displacement in the subscanning direction is derived from the variation in the scanning time between the light receiving part a and the light receiving part b. COPYRIGHT: (C)2005,JPO&NCIPI