| 摘要 |
PURPOSE:To obtain sharp color reproducibility by using a pulse lighting type light source for lighting an original, selecting the frequency of the lighting pulse as the same as the subscanning frequency and selecting the data read frequency of a line sensor as the subscanning frequency or above. CONSTITUTION:The light source of pulse emission (e.g., a discharge tube such as a fluorescent lamp or a xenon lamp) is employed as a light source lighting an original and the frequency of light emission and the frequency of one line reading by a CCD are selected to be the same to each other. Thus, the moving distance of the sensor is decreased while the lamp is emitted and the mixture of adjacent picture elements in the subscanning direction is decreased and the MTF in the subscanning direction is improved. Moreover, the lighting pulse frequency of the light source is synchronized with the subscanning frequency so as to apply readout in a short cycle in matching with the lighting time, not the readout from the CCD in one cycle within the moving time of one line in the subscanning direction. Thus, a sharp color reproducibility is obtained.
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