| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact scanning optical device reducing the magnification of a scanning optical means in a subscanning direction further than in the conventional manner, made good at high-definition printing and immune to environmental fluctuation (temperature change) and coping with scanning with plural beams. SOLUTION: This device is provided with a scanning optical means 6 constituted of fθlens systems 6a and 6b having fθcharacteristic. The 1st optical device 6a is an anamorphic lens having different convex power both in a main scanning direction and the subscanning direction, and both 1st and 2nd surfaces thereof are constituted of toric surfaces. In the main scanning direction, the 2nd surface is formed to be aspherical. As for the 2nd optical device 6b, its 1st surface is a cylindrical surface having convex power in the subscanning direction, and a diffraction optical device is formed on a place C so as to have convex power both in the main scanning direction and the subscanning direction on its 2nd surface. The fθlens systems 6a and 6b are molded of plastic material.
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