HP Deskjet 6620 Color Inkjet Printer - Manual (Page 79)

3. In the Copies box, type the number of copies that you want to print.
4. Select the Collated check box.
5. Select any other print settings that you want, and then click Print.
9.4 Automatic two-sided printing
To print a two-sided document automatically, one of the following accessories must
be attached to the printer:
Automatic Two-Sided Printing Accessory
Auto Two-Sided Print Accessory with Small Paper Tray
The two-sided printing accessories only support certain paper types. For a list of
supported paper types, see the documentation that came with the accessory.
If a two-sided printing accessory is not attached to the printer or you are printing on
an unsupported paper type, use manual two-sided printing .
HP Deskjet 6600 series printer User's Guide
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