Canon CLC5151 Reference Manual page 109

The surface of the original that you want to copy must be placed face down. Align the top edge
of your original with the back edge of the platen glass (by the arrow in the top left corner).
Place books and other bound originals on the platen glass in the same way.
NOTE
When you are enlarging an A4 or A5 original onto A3 paper, place the original horizontally on the
platen glass, and align it with the A4R or A5R marks.
3
Gently close the feeder/platen cover.
2-41
Placing Originals
2