| 摘要 |
PROBLEM TO BE SOLVED: To provide an image reader, having a simple configuration, without the need for providing current adjustment means by modes of a light-emitting element for each original lighting, in the case of reading a black-and-white original with a color image sensor of a light source changeover type. SOLUTION: LEDs of R(red), G(green) and B(blue) colors are maintained at turn-on duty ratios, equal to those at color image reading, and are turned on simultaneously or in succession, with the turn-on period reduced to 1/3, so that the forward currents of each of the R, G, B LEDs is maintained equal in the color image reading mode and in the black-and-white original reading mode.
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