HP LaserJet Enterprise M4555 MFP series - Manual (Page 190)

4. To make a two-sided copy from a one-sided
original, touch the 1-sided original, 2-sided
output button.
To make a two-sided copy from a two-sided
original, touch the 2-sided original, 2-sided
output button.
To make a one-sided copy from a two-sided
original, touch the 2-sided original, 1-sided
output button.
Touch the OK button.
5. Touch the Start button.
170 Chapter 9 Copy ENWW