Patent ID: 7432492

Claim:
An image reading apparatus comprising: a light source having a first luminescent portion that outputs a light with a first wavelength range and a second luminescent portion that outputs a light with a second wavelength range, the second wavelength range being different from the first wavelength range; a light-receiving portion that receives a reflection light reflected from an original irradiated by the light source; a scanning portion that shifts a reading position of the original read by the light-receiving portion in a vertical scanning direction, by changing a relative position between the original and the light-receiving portion; and a switching portion that alternately turns on the first and second luminescent portions when the scanning portion shifts the reading position, a vertical scanning resolution for a first data obtained from the light-receiving portion when the switching portion turns on the first luminescent portion being independently set from a vertical scanning resolution for a second data obtained from the light-receiving portion when the switching portion turns on the second luminescent portion.