To align the illuminance peaks of an illuminance distribution to the center of a reading region without changing the illuminance distribution state when an original is illuminated with an image scanner.
An illumination device is constituted by mounting and fixing an exposure lamp 9 for illuminating the original G on an original platen 7 and a reflection plate 10 for irradiating the original by reflecting the light of part of the exposure lamp 9 to the same holder substrate 40 in order to maintain a specified positional relation. This illumination device is disposed movably to a reading and scanning direction (A) with respect to a first scanning section 12 constituting a scanning optical system. As a result, the holder substrate 40 is moved at a distance C in a right direction in order to align the peak light quantity position Cc of the illuminance distribution 54 by the illumination device to the center Bc of the reading region, thereby, the peak positions can be aligned to the center and the moving regulation can be executed without collapsing the illuminance distribution state of this time.
MASUDA MAKOTO
ONO YASUHIRO
ITO TETSUTSUGU
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