| 摘要 |
PROBLEM TO BE SOLVED: To easily and surely correct the out-of-focus amount of a scanning beam caused by an environmental change, etc. SOLUTION: This optical scanner is provided with a coupling lens 2 which transforms a luminous flux emitted from a light source 1 into a parallel, convergent flux, or divergent flux, a scanning optical system 5 and 6 which deflects the luminous flux transformed by means of the lens 2 and condenses the deflected scanning beam onto a surface 7 to be scanned, and a correcting and adjusting means which corrects and adjusts the out-of-focus amount of the scanning beam on the surface 7 caused by an environmental change, etc. The correcting and adjusting means is provided with a correction optical system 3 and 4 which is positioned between the coupling lens 2 and the deflecting surface of the scanning optical system 5 and 6. The correcting optical system 3 and 4 has at least one anamorphic surface having different power in the main scanning direction and subscanning direction.
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