Brother HL 2270DW - Manual (Page 53)

Driver and Software
49
2
 For Mac OS X 10.5.x and 10.6.x
a Select Layout.
b Choose Long-edge binding or Short-edge binding in Two-Sided. Automatically the Two-Sided
check box is checked.
c
Select Paper Handling.
d
Choose All pages in Pages To Print and click Print. You can print pages on both sides of the paper.