Canon LBP 2900I User Manual page 256

IMPORTANT
If you try to close the multi-purpose tray while the rear paper guide is sticking out of
the tray, you may damage the printer. Always check to make sure that rear paper
guide is pushed all the way back into the multi-purpose tray before you close the
multi-purpose tray.
4
Close the multi-purpose tray.
5
If the paper output tray is open, close it.
Moving the Printer 5-23
5