| 摘要 |
PROBLEM TO BE SOLVED: To make the absolute minimum black correction be sufficient even for successive document reading, and to shorten a document reading cycle. SOLUTION: The black correction is a function of correcting the fluctuation in temperature/output under dark condition characteristics of a CCD line sensor 26D, and when the abscissa axis (x-axis) indicates the peripheral temperature of the CCD line sensor and the ordinate axis (y-axis) indicates the output under dark condition of the CCD line sensor 26D, the output under dark condition increases logarithmically and proportionally with a rise in the peripheral temperature. By predicting or measuring the density change of the CCD line sensor 26D and determining the propriety of the execution of the black correction, the black correction in a read interval is suppressed to the absolute minimum, and thus the successive reading time of a light source 110 is shortened. COPYRIGHT: (C)2010,JPO&INPIT |
