| 摘要 |
PROBLEM TO BE SOLVED: To obtain stable spot size by realizing the focus adjustment of a scanning beam independently in a main scanning direction and a subscanning direction without causing the change of magnification, etc. SOLUTION: This scanner is equipped with a light source 1, a shaping optical system changing a light beam from the light source 1 into a shaped light beam having specified characteristic, a deflector 4 deflecting the shaped light beam, and scanning optical systems 31 and 32 performing scanning by forming the beam spot of the light beam deflected by the deflector 4 on a surface to be scanned 17. In such a case, the shaping optical system is equipped with a condensing lens 2' changing the light beam from the light source 1 into a focused beam and a cylindrical lens 3' changing the focused beam emitted from the lens 2' into parallel beams only in the main scanning direction. The lens 3' has negative refractive power in the main scanning direction and is attached so that its movement can be adjusted in the optical axis direction of the shaping optical system.
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