| 摘要 |
PROBLEM TO BE SOLVED: To read a black-and-white original at high speed without raising cost by equalizing the ratio between the turn-on time of a plurality of kinds of respective light emitting elements and time for reading a color original for one line and reproducing the black-and-white images of the original by successively turning on these elements while reading the black-and-white original for one line. SOLUTION: A color image sensor unit 200 is provided with an optical system 29, with which emitted light 12 from a light guide source 3 is reflected on an original plane in contact with the upper face of a transparent glass board 21 and the reflected light 13 is passed through, and a sensor array 1 or the like installed on a substrate 19. In a black-and-white original read mode, the timing to turn on/off respective LED in R, G and B, for example, is set to 1/3 of turn-on time respectively without changing any turn-on duty. Therefore, the black-and-white original can be read for one line within the same time as the time for reading one color of one line in a color original reading mode. Besides, since a start pulse or the like can be outputted at the same timing, a signal processing circuit can be constituted similarly. |
