| 摘要 |
PROBLEM TO BE SOLVED: To realize a new scanning image-formation optical system capable of effectively correcting the curve of a scanning line and the deterioration of wave front aberration in an obliquely incident type optical scanner. SOLUTION: The scanning image-formation optical systems L1 and L2 are used in the optical scanner where one or more coupled beams from a light source side are deflected toward the deflecting and reflecting surface 4A of the light deflector 4 of a system where the surface 4A is rotated around a rotary shaft Ax parallel with the surface 4A by being obliquely made incident on a surface orthogonal to the rotary shaft Ax, and the deflected beams are condensed toward a surface to be scanned 5 by the scanning image-formation optical system so as to form a light spot on the surface 5, whereby the scanning of one or more scanning lines of the surface 5 is performed. The optical system includes two or more special tilt surfaces where the tilt amount of cross-sectional shape in a subscanning direction is changed in a main scanning direction. |
