Canon DR-5010C - Manual (Page 46)

44 Using the Scanner
Setting Up the Document Feed Tray and the Document Eject Tray
1.
Hold the middle of the Document Feed Tray and slowly open it toward you.
CAUTION
Do not place anything other than documents on the Document
Feed Tray. Doing so may damage the scanner, reduce scanning
quality, or cause the feed tray to fall off and injure someone.
2.
Pull out the Document Feed Tray Extension when scanning large documents.