IMAGE READING APPARATUS, IMAGE FORMING APPARATUS, AND SIZE DETECTING METHOD

摘要

According to an embodiment, an image reading apparatus includes: a light emitting body configured to emit light at illuminance lower than illuminance in reading an original document; a sensor configured to detect opening and closing of a cover; an image pickup element configured to pick up an image of the original document, on which the light from the light emitting body is irradiated, if the cover is open; and a control and determining section configured to turn on the light emitting body if the cover is opened and specify a pixel having a value exceeding a threshold from the picked-up image to determine the size of the original document.