Patent ID: 7408682

Claim:
An image reading apparatus which reads an image of a document placed on a document table, using light irradiation means moved along the document table, comprising: generation means for generating shading correction data used in units of lines, on the basis of reflection light obtained by scanning, with the light irradiation means, a white reference plate provided near the document table outside a document reading area; correction means for correcting, using the shading correction data generated by the generation means, a to-be-read image corresponding to each of the lines and obtained by scanning the document table with the light irradiation means; and supply means for applying a power supply voltage of a frequency to the generation means and the correction means, the frequency being equal to integral multiples of a reading frequency corresponding to each line, wherein uneven image density caused by a ripple in the supply means is controlled to occur at a specific part of pixels for each line, and is corrected by the correction means.