Patent ID: 8115975

Claim:
An image scanning device, comprising: an optically transparent document table; a pressing unit configured to press a document against the document table at a closed position, the pressing unit being movable between the closed position and an open position; an operation detection unit configured to detect an opening operation of the pressing unit from the closed position to the open position and a closing operation of the pressing unit from the open position to the closed position; a movable scanning unit holding a light source and configured to scan a target surface of the document by illuminating the target surface through the document table with light emitted from the light source while moving along the target surface; an image sensor configured to receive the light reflected from the target surface and to convert the light into image data; a control unit configured to move the movable scanning unit from a standby position to a document-size detection start position when the opening operation of the pressing unit is detected by the operation detection unit, to move the movable scanning unit from the document-size detection start position to the standby position to scan the document and thereby obtain the image data of the document when the closing operation of the pressing unit is detected by the operation detection unit, and to determine a size of the document based on the obtained image data; and a detection-start-position arrival detecting unit configured to detect arrival of the movable scanning unit at the document-size detection start position, wherein the control unit is configured to continue moving the movable scanning unit from the standby position to the document-size detection start position until the arrival of the movable scanning unit at the document-size detection start position is detected by the detection-start-position arrival detecting unit even if another operation of the pressing unit is detected after starting to move the movable scanning unit from the standby position to the document-size detection start position based on the detection of the opening operation and to stop the movable scanning unit at the document-size detection start position.