Print From Your Computer : Macintosh Printing (Mac OS X 10.5 and 10.6)

Print Double-Sided
Using the auto duplexer, you can print on both sides of the page automatically.
1.
Select 2-sided Printing Settings from the pop-up menu.
2.
Select 2-sided Printing.
Note:
If the 2-sided Printing checkbox is grayed out in the application you are printing from, select A4 in the Paper Size box, then click the 2-sided Printing checkbox and select the double-sided printing options you want. Then change the Paper Size setting back to Letter.
3.
4.
5.
Click Adjustments to adjust the print density and drying time to prevent ink from bleeding through the page when you print on plain paper.
When you’re finished, you’re ready to print.