HP Deskjet 6127 Color Inkjet Printer - Manual (Page 46)

printing instructions
Follow these instructions to print a two-sided document:
1. Open the Printer Properties dialog box, then select the Features tab.
2. Check Two-Sided Printing .
The Two-Sided Printing Margin dialog box appears.
3. Select the appropriate page content option, then click OK to return to the Features tab.