Canon i-SENSYS MF729Cx Important Safety Instructions And Installation Manual page 66

Tap <X>.
Input the length of the <X> side using
3
Specify the length of the <Y> (longer) side.
Tap <Y>.
Input the length of the <Y> side, and tap <Apply>.
4
Tap <Apply>.
5
Select the paper type.
LINKS
Loading Paper in the Manual Feed Slot
Limiting the Paper Sizes Displayed
Paper
/ or the numeric keys, and tap <Apply>.