| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical scanner, multi-beam scanner and image forming apparatus, compensating for fluctuation due to a temperature change by disposing a diffraction optical element having no power in a first optical system. SOLUTION: This optical scanner has a first scanning lens 107 and a second scanning lens 108, which convert a light beam emitted from a light source 101 to a desired condensing state, image the same in the sub-scanning direction to be imaged into a line image elongated in the main scanning direction in the vicinity of a deflector, and scan and image the deflected light beam on the surface to be scanned. The first optical system includes a plurality of lenses provided corresponding to a light source and held on a single member, and the first optical system includes a diffraction optical element 104 having no power at least at an ordinary temperature. COPYRIGHT: (C)2010,JPO&INPIT
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