| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical scanner which can excellently correct curvatures of field of scanning optical systems on both sides of a deflector and facilitate the machining and fitting of scanning optical elements. SOLUTION: The optical scanner has the scanning optical elements arranged on both sides across a deflector, and at least one scanning optical element 10B arranged on one side of the deflector has at least one surface which does not have an axis of symmetry in a horizontal scanning direction and also has a reference plane 20 for restricting the position in a vertical scanning direction. The surface of the scanning optical element arranged on the opposite side across the deflector has an area nearly conforming with a shape obtained by rotating the surface having no axis of symmetry in the horizontal scanning direction by 180 deg. about the reference plane 20 on an axis 30 of rotation. |
