Patent ID: 8014044

Claim:
An image scanning device, comprising: a platen having a manuscript scanning area, a front side, and a back side, the platen being configured to have a manuscript disposed on the front side thereof; an image scanning part being configured to scan an image on the manuscript disposed on the manuscript scanning area from the back side of the platen; a light source being configured to irradiate light to the manuscript scanning area from the back side of the platen; a platen cover being allowed to be positioned in a closed state or in an opened state, the closed state preventing light from entering the manuscript scanning area from the front side of the platen, the opened state allowing light to enter the manuscript scanning area from the front side of the platen; a light receiving part being configured to receive light from the manuscript scanning area on the back side of the platen; the light receiving part is configured to classify a magnitude of the amount of received light into three or more levels; a range obtaining part being configured to obtain a range between an amount of received light of the light receiving part in the opened state of the platen cover and an amount of received light of the light receiving part in the closed state of the platen cover, wherein the range obtaining part is configured to obtain a difference among the levels as the range; a manuscript detecting part being configured to detect existence of a manuscript in the manuscript scanning area based on the range.