Canon LBP6780x Manual page 569

[Default Paper
[Plain], [Plain L], [Heavy 1], [Heavy 2],
Type]
[Transparency], [Envelope], [Labels]
[2-Sided Printing]
[Off], [On]
If you cannot specify the paper type or if
you print from DOS, UNIX, or other
operating system, specify the paper type
in this item.
"Usable Paper"
Specifies whether the printer should print
on one side or both sides of the paper.