| 摘要 |
PROBLEM TO BE SOLVED: To obtain the optical scanning device which can decrease the frequency of the folding of an optical path and maintain high speediness and high resolution. SOLUTION: The optical scanning device is equipped with a light source part 12 which emits light beams and a polygon mirror 28 having more than one reflecting a surface and includes a surface tilt correction optical system which corrects the surface tilt of the reflecting surfaces of the polygon mirror 28 and an overfield optical system which makes luminous flux wider than the width of the reflecting surfaces of the polygon mirror 28 in the horizontal scanning direction incident. A cylindrical lens 18 is provided which has negative refracting power in both the horizontal and vertical scanning directions and also has the refracting power larger in the vertical scanning direction than in the horizontal scanning direction. Consequently, the cylindrical lens 20 can be separated from a plane mirror, so the optical path needs to be folded only once. |
