| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical scanner of compact construction which corrects image plane curvature and distortion aberration in the main scanning direction and the image plane curvature, variation of the magnification in the subscanning direction or the like, and which is suitable for printing with high definition and an image forming device using the same. SOLUTION: In the optical scanner where light flux from a light source means is imaged on the surface to be scanned by a scanning optical means through a deflection means, the scanning optical means has a first and a second fθlenses. The first fθlens is a meniscus-like positive lens whose concave surface is turned to a deflection means side in a main scanning cross section. The second fθlens is a meniscus-like lens whose convex face is turned to the deflection means side in the main scanning cross section, the shape in the main scanning cross section of the incident plane of the second fθlens is reversed from a convex to a concave from on the optical axis of the lens to both ends of the effective part of the lens, and the surface position in the both ends of the effective part of the lens is located at the deflection means side from the position of the surface vertex on the optical axis of the lens.
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