Patent ID: 7619785

Claim:
An image reading apparatus comprising: a light source that irradiates a document; a sensor that receives reflection light reflected from the document; a reference member that is read by the sensor; and an abnormal site detection unit that detects, using first reading data acquired by reading at a position of the reference member according to a first intensity of irradiation light irradiated by the light source and second reading data acquired by reading at the same said position of the reference member according to a second intensity of irradiation light, which is smaller than the first intensity of irradiation light irradiated by the light source, abnormal sites in the first reading data or the second reading data; wherein the abnormal site detection unit detects, as the abnormal sites, sites where a difference between the first reading data of the position of the reference member read by the first intensity of irradiation light and the second reading data of the same position of the reference member read by the second intensity of irradiation light is smaller than a threshold value.