| 摘要 |
PROBLEM TO BE SOLVED: To provide an image scanning device which suppresses worsening of banding regardless of magnitude of dynamic range of a light source and prevents reduction in life of the light source.SOLUTION: An optical scanning device has an optical deflector 202b that deflects light emitted from a light source 101-1 comprising a VCSEL to scan a surface of a photosensitive drum 504. A shutter device 700, which functions as a light volume adjuster, is located between a prism beam splitter 203 and a 1/4 wavelength plate 204. The shutter device 700 is provided with an ND filter 700-7, or neutral density filter, which is inserted into a light path when a low line speed mode is used, which is the case when thick paper sheets or the like are used. Light volume is reduced when the light passes through the ND filter 700-7. Exposure energy can be thus adjusted to an appropriate level without having to alter intensity of the light source, which allows scanning using all mirror faces without having to skip faces even in the low line speed mode. |
