| 摘要 |
PROBLEM TO BE SOLVED: To provide an image scanner that can suppress the occurrence of lateral stripes on an image and deterioration in the S/N. SOLUTION: A timing generating circuit is provided with an oscillator, a frequency spread device that spreads a frequency of a pulse outputted from the oscillator, a timing generating circuit that generates a timing signal for a CCD for reading an image and a signal processing circuit at the post-stager of the CCD from the pulse whose frequency is spread, and a spread rate changeover circuit that switches the frequency spread rate of the frequency spread device. A caption LSYNC denotes a main scanning synchronizing signal that is used to take synchronization in the main scanning direction when an image of an original is read and a caption LGATE depicts a main scanning gate signal that validates reading of the image by the CCD when the LGATE signal is at an L level. A microcomputer that controls the entire image scanner switches two signals Q1, Q2 to be outputted to the frequency spread device when the image is not valid, that is, the LGATE signal is at an H level. The timing of this switching is synchronously performed with the signal LSYNC.
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