US Patent 7911661 Image reading device

There is provided an image reading device, which comprises an illumination unit configured to diffuse light from light sources in a predetermined scanning direction to illuminate an object with diffused light, a reading unit having photoreceptors aligned in the predetermined scanning direction to receive light reflected from the object, a detection unit configured to detect lighting status of the light sources; and a controller that obtains an image of the object by using a normal one of the light sources as a main light source if at least one of the light sources is in an abnormal state.