OPTICAL SCANNING OPTICAL DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an optical scanning optical device used for an image forming device realizing high resolution, which can be miniaturized by reducing the number of components of a lens or the like. SOLUTION: The deflection surface of a polygon mirror 45 is irradiated with a laser beam emitted from an LD 42 and deflection and scanning is performed. Image forming on the surface of a photoreceptor drum 4 is performed with one or plural f-θlenses. An LSU 6a detects the image-formation timing on the surface of the photoreceptor drum 4 of the laser beam by a photosensor 48. An optical path which arrives from the LD 42 to the polygon mirror 45 and an optical path which arrives from the polygon mirror 45 to the photosensor 48 are crossed. A laser beam having the light-harvesting characteristics of two axial directions and irradiated from the LD 42 by one condensing shaft is made to condense at the position in the subscanning direction through the deflection surface of the polygon mirror 45. A combined lens 55a which makes the laser beam deflected by the polygon mirror 45 condense on the photosensor 48 with the other condensing shaft is arranged.