| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical scanner performing scanning by forming an image with a plurality of light beams on a surface to be scanned as a beam spot, capable of adjusting an interval between the beam spots in a subscanning direction to a desired value, maintaining the stable diameter of the beam spot because the fluctuation of the diameter of the beam spot by such adjustment is small, and applied to an image forming apparatus, whereby the high-quality image is obtained, and to provide the image forming apparatus using the optical scanner. SOLUTION: The optical scanner is equipped with a beam spot interval varying means to vary the subscanning direction component of the interval of the beam spot on the surface to be scanned, and the beam spot interval varying means is equipped with a diffraction grating 20. The diffraction power of the grating 20 is different according to places, and the beam spot interval varying means moves the grating 20. In the beam spot interval varying means, the grating 20 is inclined centering an axis nearly parallel with a main scanning direction or an axis nearly parallel with a light beam incident direction. COPYRIGHT: (C)2004,JPO
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