| 摘要 |
PURPOSE:To condense light on the surface of a photosensitive body without passing a light-semitransmissive means by providing a toroidal lens between a deflector and a spherical mirror and inclining and arranging the toroidal lens and the spherical mirror in a plane perpendicular to a deflecting face. CONSTITUTION:In a light beam scanning optical system, a spherical mirror 20 is used instead of an ftheta lens and the scanning speed in the main scanning direction is so corrected that it is uniform throughout from the center to both end parts of the scanning area. A toroidal lens 13 is provided between a polygonal mirror 10 and the spherical mirror 20, and the toroidal lens 13 and the spherical mirror 20 are inclined and arranged in a plane perpendicular to the deflecting face. Consequently, the luminous flux is reflected in a direction different from the incidence direction by the spherical mirror 20 and is condensed on the surface of a photosensitive body 30 without using a light-semitransmissive means like a beam splitter. Curvature of a scanning line on the surface of the photosensitive body 30 due to inclination of the spherical mirror 20 is corrected because the toroidal lens 13 is inclined similarly. |
