Epson Stylus Pro 4400 Reference Manual page 148

Standard double-sided printing
To print odd and even numbered pages on the opposite sides of
a sheet, follow the steps below.
1. Select the Double-Sided Printing.
2. Click Margins. The following dialog appears.
3. Specify the edge of the paper where binding will be placed.
You can choose Left, Top, or Right.
4. Specify the width of the binding margin, using the Binding
Margin text box. You can specify any width from 3 to 30 mm.
148
Printing with Mac OS 9.x