| 摘要 |
PROBLEM TO BE SOLVED: To provide a laser scanner capable of excellently correcting the field curvature in subscanning, the uniformity of optical magnification in a subscaning direction and groove-shaped aberration, outputting an excellent image all over the scanning area and further realizing high-sped plotting by using plural beams. SOLUTION: A laser beam 2 emitted from a laser beam source 1 is deflected by a polygon mirror 5 so as to scan the image plane 7a of a photoreceptor 7, and also formed into an image on the surface 7a by a scanning optical system 6 arranged on an optical path. In such a case, the system 6 is composed of a 1st scanning lens 6a, a 2nd scanning lens 6b and a 3rd scanning lens 6c in laser beam passing order. The 1st scanning lens 6a nearest to the mirror 5 and the 3rd scanning lens 6c nearest to the image plane 7a out of the scanning lenses 6a to 6c are constituted to have a plane where curvature on a subscanning cross section is changed independently of the shape in a main scanning direction. |
