IMAGE READING APPARATUS AND METHOD USING LIGHT SHUTTER FOR BLOCKING LIGHT FROM A LIGHT SOURCE

An image reading apparatus includes a light source for illuminating a document, and a line image CCD for performing photoelectric conversion on the light reflected from the document. Particularly, the image reading apparatus further includes a light shutting device for selectively shutting off the light directed toward the line image CCD, and a processing section for obtaining, as reference black data, the output data of the line image CCD produced in a state where the light directed toward the line image CCD is shut off, for obtaining, as image data of the document, the output data of the line image CCD produced in a state where the light directed toward the line image CCD is not shut off, and for performing shading correction on the image data according to the reference black data.