| 摘要 |
PROBLEM TO BE SOLVED: To provide a means which assures a sufficient light quantity with a simple structure with a synchronization detection sensor used in a scanning and focusing optical system. SOLUTION: The optical scanner has a scanning optical system including at least: a light source 107 which is modulated and driven; a deflector 106 to scan a luminous flux from the light source 107; and a scanning and focusing element 124 to focus the scanned luminous flux onto a face to be scanned; a focusing lens 114 to guide the luminous flux from the light source 107 to the deflector 106; and at least one synchronization detection sensor 140 to synchronize the lighting timing on the face to be scanned provided outside of an image region, wherein the scanning optical system is provided with at least one or more turning back mirrors 132, and the number of the scanning optical system mirrors 132 is larger than that of the synchronization optical system mirrors, thus the light utility efficiency of the scanning optical system is made smaller than that of the synchronization optical system. COPYRIGHT: (C)2008,JPO&INPIT
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