| 摘要 |
PURPOSE:To make it unnecessary to place a detecting sensor, and to improve the efficiency of a copying operation by providing an illuminating system for radiating a light beam to an original, an image sensor, a circuit for amplifying an analog signal, and an A/D converting circuit, detecting a size of an original by using them in common, and also, reading the original image density information. CONSTITUTION:A line image sensor 9 is driven by a sensor driver 12, and an output signal of the line image sensor 9 is amplified by an amplifier 13, and converted to a digital signal of 6 bits by an A/D converting part 14. Thereafter, shading correction 15 for correcting an uneven illuminance of a light source and a sensitivity variance, etc., of an element of the line image sensor 9 is executed, and an out-of-focus by an optical system is corrected by an MTF correcting part 16. As for the main scanning direction, a variable power method by a processing of an electric signal is used, and as for the sub-scanning direction, the correction is executed by changing a moving speed of running bodies 10, 11, in a state that a read timing of the image sensor 9 remains as it is. A data which is brought to variable power is binarized by a prescribed threshold value by a binary processing part 18, and outputted to a printer part by an outputting circuit 19.
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