| 摘要 |
PROBLEM TO BE SOLVED: To facilitate aberration correction in an optical scanning lens.SOLUTION: A tandem type scanning optical system comprises: a polarizer 8 that has a face on which a plurality of light beams emitted from a plurality of light sources are made incident on, the face having a diagonal incident angle in a sub-scanning direction, and the polarizer 8 being rotated around an axis parallel to this sub-scanning direction, thereby scanning the plurality of light beams, made incident on the face, in the sub-scanning direction; splitting means 9,9configured to split the plurality of light beams scanned by the polarizer 8 into individual light beams; and a plurality of scanning lenses 10a to 10d provided so as to correspond to target scan surfaces, at least one for each, and configured to converge light beams split by the splitting means 9,9and emit it toward the corresponding target scan surfaces. One face of each of the scanning lenses 10a to 10d has an asymmetrical shape in the sub-scanning direction, and one face of each of the scanning lenses 10e to 10d has an asymmetrical shape in a sub-scanning direction. The optical axes of the scanning lenses 10a to 10d are eccentric to a face of the polarizer 8, which face is perpendicular to the rotation axis. |
