HP Color LaserJet 4600 Printer series - Manual (Page 95)

ENWW 81
Options for binding 2-sided printing jobs
Before printing a 2-sided document, in the printer driver choose the
edge on which you will bind your finished document. Long-edge or
book binding is the conventional layout used in book binding. Short-
edge or tablet binding is the typical calendar binding.
Note The default binding setting is to bind on the long edge when the page
is set up for portrait orientation. To change to short edge binding, click
the Flip Pages Up check box.