| 摘要 |
PROBLEM TO BE SOLVED: To obtain a multi-beam optical scanning device which suppresses the curvature of main scanning lines and increases the picture quality of a print image by providing an image forming means or the like which image-forms plural light beams scanned by a scanning means at specified positions on an object to be scanned, etc. SOLUTION: An after-deflection optical system 21 gives specified aberrational characteristics to four laser beams L deflected by respective surfaces of an optical deflection device 5 over the entire area of the length direction of the horizontal scanning direction of a laser beam L (Y, M, C, and B) deflected by the optical deflection device 5 to a photoreceptor drum 58. Further, this device has 1st-3rd image forming lenses 27, 29, and 31 as optical means for suppressing variation of the image of formation plane of the laser beam L within a certain range. Further, dustproof glass parts 39Y, 39M, 39C, and 39B are arranged where the four laser beams L are emitted from the multi-beam optical scanning device 1. Consequently, the horizontal scanning line curvature of the laser beam L is suppressed and the laser beam is guided to the photoreceptor drum 58. |
