OPTICAL SCANNER AND IMAGE FORMING APPARATUS PROVIDED WITH OPTICAL SCANNER

摘要

PROBLEM TO BE SOLVED: To provide an optical scanner capable of suitably correcting wavefront aberration on a photoreceptor drum and obtaining a suitable beam diameter and a suitable beam profile on the photoreceptor drum. SOLUTION: The image forming apparatus provided with the optical scanner 21 comprises: a semiconductor laser element 41; a pre-deflection optical system 40; a polygon mirror 50 which scans luminous flux imaged by the pre-deflection optical system 40 with respect to a photoreceptor drum 23 as a scanning object; and a post-deflection optical system 60 which images the scanned luminous flux onto the photoreceptor drum 23. The optical scanner has an over-illumination scanning optical system where the width of luminous flux made incident to a polygon mirror from a pre-deflection optical system 40 is larger than the width of one reflection surface of forming the polygon mirror 50, wherein at least two flat plates which transmit the luminous flux scanned by the polygon mirror 50 are disposed. COPYRIGHT: (C)2009,JPO&INPIT