Patent ID: 7787157

Claim:
An image reading apparatus, comprising: a plurality of sensors that execute photoelectric conversion of a plurality of hues; and a correction unit that corrects displacement of image data caused by intervals between the plural sensors and includes a first draft reading mode whose scanning direction by the sensors is the same at the time of scanning a sheet and at the time of shading correction, and a second draft reading mode whose scanning direction by the sensors is different at the time of scanning the sheet and at the time of shading correction, wherein: the correction unit comprises a plurality of paths including a different number of delay units disposed in each path, and changing over units that change over a connection between the sensors and the paths; the changing over units operate such that the connection between the sensors and the paths are different at the time of reading image data and the shading correction in the first draft reading mode and at the time of reading image data in the second draft reading mode to compensate for different scan directions relative to the plural sensors; and the changing over units are disposed in front of and at the back of the plural paths, and when a block executing the shading correction exists between the front changing over unit and the back changing over unit, correction data for the shading correction are set again before reading the image data in the second draft reading mode.