Canon i-SENSYS MF729Cx Important Safety Instructions And Installation Manual page 521

Paper Sources
Select the paper source that you want to change the setting for.
<Speed Priority>
When using paper that has been preprinted with a logo, you need to change how it is facing when you perform 1-
sided and 2-sided printing.
We recommend selecting <Speed Priority> if you do not need to consider which side to print on.
<Print Side Priority>
To print on a specific side of paper, you do not need to flip over paper in the paper source whether 1- or 2-sided
printing is selected.
If <Print Side Priority> is set for a paper source that is loaded with paper you cannot use for 2-sided printing
( Paper), <Speed Priority> is applied to the paper source instead. In this case, you need to load the paper in
the same way as when <Speed Priority> is selected (
1-sided printing speed may be slower when <Print Side Priority> is selected.
Loading Preprinted Paper).