Patent ID: 8786917

Claim:
A method comprising: a first step of passing a document through a reading unit and returning the document to an upstream of the reading unit; a second step of passing the document returned in the first step through the reading unit and returning the document to the upstream of the reading unit; and a third step of passing the document returned in the second step through the reading unit, and then discharging the document, wherein, in one of the first and third steps, the reading unit reads an image formed on a first surface of the document and, in the other of the first and third steps, the reading unit does not read the image formed on the first surface of the document, wherein, in the second step, the reading unit reads an image formed on a second surface of the document, wherein the second surface is a back surface of the first surface of the document, and wherein a speed of passage through the reading unit without reading the image in one of the first and third steps is higher than a speed of passage through the reading unit in the other of the first and third steps.