| 摘要 |
PROBLEM TO BE SOLVED: To provide an image reader that can optimally decide a phase of a sample hold signal and obtain a stable image digital signal not affected by an environmental change or the like. SOLUTION: A phase control means 6 applies phase control to a sample hold signal pulse to sample and hold an output signal of a CCD 4 at a large step and a small step to form sets of pulse LP1, LP2, LP3 whose phases are changed at a large stepΔT having a couple of sample hold signal pulses SP1, SP2 whose phases are changed at a small stepΔt. Level differences of the output signal respectively subjected to sampling and holding by the two pulses by each set of the pulses are obtained and compared and output signal sample hold timing of the sample and hold signal pulse of a set with the least level difference is decided as output signal sample hold timing of a regular sample hold signal.
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