| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a document reading apparatus in which a white reference plate for shading correction of a reading sensor is prevented from getting dirty, a document is brought into close contact with a document platen and provided with a white reference unit for making a distance from the document platen to the white reference plate to be constant. <P>SOLUTION: At both ends of a white reference plate, rollers are provided, and the rollers are supported by the white reference plate so as to be movable vertically. When there is no document and the white reference plate is read, the white reference plate is at the lowest position. When there is a document, the hight varies by the roller according to the thickness of the document. In order to prevent floating of the document at the position corresponding to an overlapping portion of a reading sensor, the roller used at the portion is slightly larger than that of the other positions so as to increase a load imposed on the overlapping portion of the document. Thus, variation in reading sensors with respect to reading data in the overlapping portion is able to be reduced. <P>COPYRIGHT: (C)2012,JPO&INPIT |
