| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a scanning optical apparatus that reduces curvature of an image in main scanning direction, which is caused when the light beams from a plurality of light emitting parts spaced from each other in main scanning direction pass through an incident optical system. <P>SOLUTION: The shape of the optical face in main scanning cross section of optical elements 3, 4 configuring an incident optical system LA is non-circular arc on which positive power decreases from the on-axis toward the off-axis. When W (mm) is the distance between light emitting parts which are most distant from each other in the main scanning direction among a plurality of light emitting parts of a light source means 1, La (mm) is the optical path length from the optical face closest to the light source means among the non-circular arc optical faces of the incident optical system to a diaphragm 5, f (mm) is the focal length of the incident optical system in the main scanning direction, and as D (mm) is the width in the main scanning direction of the luminous flux emitted from the light emitting part which is mostly remote in the main scanning direction on the optical face closest to the light source means among the non-circular arc optical faces of the incident optical system, the following expression (1) is satisfied: 2D≥¾W×La/2f¾≥D/8. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
