| 摘要 |
An optical scanning device includes a rotary polygonal mirror, an input optical system for direct a light beam from a light source to a deflecting surface of the rotary polygonal mirror, and an imaging optical system for imaging the deflected light beam on a scan surface, wherein in a main scan section the light beam incident on the deflecting surface has a beam width wider than a width of the deflecting surface, wherein at least one optical surface of at least one imaging optical element of the imaging optical system has a shape in the sub-scan section which shape is a non-arcuate shape including an aspherical coefficient of quartic or higher order, and wherein the aspherical coefficient of quartic or higher order changes in the main-scan direction and from a scan central portion of the imaging optical element to a scan end portion of the imaging optical element.
|
