Patent ID: 7764408

Claim:
A document reading apparatus comprising: a document feed device configured to separate documents and to feed the documents one by one from a paper feed tray; an image reading device configured to read an image of each the documents at a reading position provided on a reading glass plate; a document feeding path formed between the paper feed tray and a paper discharge tray, in which each of the documents is fed in a feeding direction from the paper feed tray to the paper discharge tray via the reading position; a document holding member arranged on a front surface side of the reading glass plate at a position opposing the image reading device; a first reading pattern mark provided on the document holding member at a first position opposing the surface of the reading glass plate; a second reading pattern mark provided on the document holding member at a second position opposing the surface of the reading glass plate, wherein the second position is different than the first position, and the first reading pattern mark comprises a first form and the second reading pattern mark comprises a second form which is different than the first form, wherein the first reading pattern mark has a first length and the second reading pattern mark has a second length, and each of the first length and the second length is greater than a width of each of the documents; and a control device configured to determine the width of each of the documents by sensing a first boundary of a left side edge of each of the documents and a second boundary of a right side edge of each of the documents with respect to the first reading pattern mark and the second reading pattern mark in the primary scanning direction when each of the documents passes over the first position and the second position, wherein the first reading pattern mark and the second reading pattern mark are arranged in an alternating pattern along the primary scanning direction.