| 摘要 |
PROBLEM TO BE SOLVED: To reduce image deviation in the sub-scanning direction by making to coincide a surface phase between respective polygon mirrors with each other even when positional relations of the mirror surfaces of respective polygon mirrors with Hall elements, etc., are different between respective polygon mirrors. SOLUTION: In a light beam scanner provided with plural sets of plural light beam scanning units, plural Hall elements 11 are provided in the rotational direction of the polygon mirror corresponding to respective remaining polygon mirrors 9 excepting a reference polygon mirror, and time differences between output signals of respective laser beam detectors 13 related to respective remaining polygon mirrors 9 and the output signal of the laser beam detector 13 corresponding to the reference polygon mirror 9 are calculated. Then, a controller 14 selecting one Hall element 11 used for equal speed control of a polygon motor 10 from plural Hall elements 11 for the remaining polygon mirrors 9 based on the calculation values of the time differences is provided. |
