Patent ID: 8310690

Claim:
An image reading apparatus comprising: an original placement table on which an original is to be placed; a light source which irradiates the original placed on the original placement table with light; an image reader which reads an image of the original based on light reflected from the original when the original is irradiated by the light source; a reference member used as a lightness reference of the image reader; an adjusted value acquiring unit which acquires a light source adjusted value for adjusting the light source based on a read result at the time when the image reader reads light reflected from the reference member irradiated by the light source; a white correction data acquiring unit which acquires, as white correction data, a read result at the time when the image reader reads the light reflected from the reference member irradiated by the light source which is adjusted by the light source adjusted value; a black correction data acquiring unit which acquires, as black correction data, a read result at the time when the image reader reads the light reflected from the reference member at the time of turning off the light source; a first outside light deciding unit which decides whether outside light entering the original table is present or absent based on the light source adjusted value; an adjusted value modifying unit which modifies the light source adjusted value from the light source adjusted value acquired by the adjusted value acquiring unit to a predetermined light source adjusted value when the first outside light deciding unit decides that the outside light is present; a second outside light deciding unit which decides whether outside light entering the original table is present or absent based on the white correction data and the black correction data; a black correction data modifying unit which modifies the black correction data from black correction data acquired by the black correction data acquiring unit to predetermined black correction data when the second outside light deciding unit decides that the outside light is present, and does not modify the black correction data when the second outside light deciding unit decides that the outside light is absent; and a read result correcting unit which corrects a read result in which the image reader reads the light reflected by the original based on the white correction data and the black correction data output from the black correction data modifying unit.