Patent ID: 7428080

Claim:
An image reading apparatus comprising: a light source unit containing a first light source that emits light having a wavelength in a visible range and a second light source that emits light having a wavelength in an invisible range; an image reading unit that forms an image of a transparent object illuminated by the light source unit on an image pickup element via an optical system; and image scanning means for selectively obtaining image information of the object illuminated by the first light source or the second light source by moving the light source unit, the image reading unit, and the object relatively in a sub scanning direction such that an image of the object, which is illuminated by the first light source or the second light source, is selectively formed on the image pickup element, wherein the first light source emits light even in obtaining operation of an image of the object illuminated by the second light source, and wherein the first light source and the second light source of the light source unit are positioned at the same side of the object and opposing to said image reading unit and adjacent to each other in the sub scanning direction, and are separated by a light-shielding member so as to prevent the light from the first light source from leaking into the image information of the object illuminated by the second light source.