Patent ID: 8130424

Claim:
An image scanner comprising: a first scanning unit arranged to scan a first surface of an original; a second scanning unit arranged to scan a second surface of the original; a conveyance path along which the first and second scanning unit are disposed; an inversion unit operable to invert an original passing through the conveyance path, the inversion unit being operable to guide the inverted original to pass through at least part of the conveyance path again; a storage unit configured to store image data from the first scanning unit and the second scanning unit; a size detection unit configured to detect an original size, and a selection unit configured to alternatively select one of a first mode and a second mode in accordance with the size detected by the size detection unit, wherein when the detected size of the image data is able to be stored in the storage unit, the first mode is selected and the first and second scanning unit respectively scan the first surface and the second surface of an original passing through the conveyance path without inverting the original and when the detected size of the image data is not able to be stored in the storage unit, the second mode is selected and the first scanning unit scans the first surface of the original passing through the conveyance path and the first scanning unit scans the second surface of the original, the first surface of which having been scanned by the first scanning unit, inverted by the inversion unit.