| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce total size of an optical scanning device having common deflection means for deflecting a plurality of light beams for a plurality of scanning surfaces.SOLUTION: An optical scanning device includes; first and second imaging optical systems for focusing first and second light beams, respectively, coming via common deflection means on first and second scanning surfaces, respectively; and a plurality of reflective optical elements for bending first and second light paths such that each light path crosses itself in a sub-scanning cross-section. An effective image region W (mm) in a main scanning direction on each of the first and second scanning surfaces and a distance Dp (mm) between the first and second scanning surfaces in the sub-scanning cross-section satisfy a predetermined relationship. In a main scanning cross-section, a convergence degree m of each of the first and second light beams, which is expressed in terms of distance Sk (mm) from a rear principal plane of each of the first and second imaging optical systems to respective one of the first and second scanning surfaces and a synthetic focal length f (mm) of each of the first and second optical systems, shall be within a predetermined range.</p> |
