Patent ID: 7969622

Claim:
An image reading apparatus comprising: a platen on which an original is to be placed; an openable and closeable cover for covering the platen; an original illuminating light source; a plurality of photoelectric conversion elements mounted on a sensor board; and an image formation element array including a plurality of image formation elements arranged in an array, and performing a reading operation to read an image with the original placed on the platen, the image being formed on the plurality of photoelectric conversion elements through the image formation element array; a white reference generator for generating a white reference value by reading reflected light from a white reference member by using the plurality of photoelectric conversion elements, the reflected light being generated by turning on the original illuminating light source to illuminate the white reference member; a detector for detecting an output signal from the photoelectric conversion elements when the reading operation is performed with the cover open and the original illuminating light source turned on; a comparator for comparing the output signal with the white reference value on a scan-line-by-scan-line basis; and a controller for, if the comparison by the comparator shows that a value greater than or equal to the white reference value exists in the output signal, turning off the original illuminating light source to perform the reading operation on a scan-line-by-scan-line basis.