Patent ID: 7847985

Claim:
An image-reading apparatus, comprising: a sheet transfer unit that transfers a sheet; a first light-receiving device that receives light reflected from the sheet; a second light-receiving device disposed a predetermined distance from the first light-receiving device along a transfer direction in which the sheet transfer unit transfers the sheet; a first lighting unit that illuminates a readout position to be read by the first light-receiving device at a first ratio between an intensity of illumination from one side along the transfer direction and an intensity of illumination from the other side along the transfer direction; a second lighting unit that illuminates a readout position to be read by the second light-receiving device at a ratio, which differs from the first ratio, between an intensity of illumination from one side along the transfer direction and an intensity of illumination from the other side along the transfer direction; a delay unit that delays one of a first signal which is output from the first light-receiving device and a second signal which is output from the second light-receiving device to correct a delay caused by a displacement between the readout position associated with the first signal and the readout position associated with the second signal; a correction signal generation unit that generates a correction signal based on a difference between the first signal and the second signal, one of which has been delayed by the delay unit; and a correcting unit that corrects at least one of the first signal and the second signal using the correction signal generated by the correction signal generation unit.