Document reading apparatus

A document reading apparatus for reading an original document moving thorough a reading position, comprising:

• a paper feed tray to mount an original document;
• a paper discharge tray to store the original document;
• transport means for transporting the original document to the paper discharge tray from the paper feed tray;
• a U-shaped transport path extending from the paper feed tray to the paper discharge tray;
• contact glass having a predetermined reading position to read the original document;
• reading means, disposed on the inner side of the U-shaped transport path, for reading the original document fed through the contact glass;
• a backup unit, disposed opposite to the contact glass, having a transparent member forming a path between the transparent member and the contact glass to pass the original document and a white member disposed on the rear side, different from the contact glass side, of the transparent member;
• a guide member having a guide portion for guiding the original document to be transported to the contact glass and a concave portion into which the backup unit is removably inserted;
• and
• support means for exposing the contact glass, while supporting the guide member to be able to rotate to a position enabling the backup unit to be removable with respect to the concave portion of the guide member.