Patent ID: 7525693

Claim:
An image reading apparatus comprising: an optical reading system adapted to move in a predetermined direction to read an image of a stationary document placed on a document glass and to remain at a predetermined position to read an image of a moving document; an optical system control part that operates to: when the optical reading system reads a stationary document, make the optical reading system obtain first shading compensation data by reading a white reference plate through the document glass in a first predetermined range along the direction of movement of said optical reading system, and when the optical reading system reads a moving document, make said optical reading system obtain second shading compensation data by reading said white reference plate through said document glass in a second predetermined range different from the first predetermined range along the direction of movement of said optical reading system; and a compensation part that performs shading compensation based on the first shading compensation data when the optical reading system reads a stationary document and performs shading compensation based on the second shading compensation data when the optical reading system reads a moving document.