Patent ID: 6992800
Filing Date: 2006-01-31
Classification: H04N

Abstract:
1. An image reading apparatus for moving a document reading unit to a point below a document feeder that feeds documents, and emitting light from a light source of the document reading unit toward a feed roller of the document feeder, whereby light reflected from a document that travels between the feed roller and the light source is sensed by the document reading unit to thereby read an image on the document, said apparatus comprising: a photoelectronic converter for outputting an electric signal that conforms to amount of incident light; and a reading position setting unit adapted to move the document reading unit, irradiate the feed roller with light from the light source at each position to which the document reading unit is moved, cause said photoelectronic converter to output an electric signal that conforms to amount of light reflected from the feed roller at each position, detect a range in a sub-scan direction over which this electric signal exceeds a predetermined threshold value, and set a position at the center of this range as a reading position.