HP Deskjet 6940 - Manual (Page 127)

5. Remove any paper from inside the duplexer.
6. Close the duplexer, and then re-attach the duplexer to the printer.
Option for two-sided printing cannot be selected
The printer driver cannot sense the duplexer until a print job is sent to the printer. Print
a single-sided document, and then print the two-sided document. The option for using
the duplexer will appear in the printer software.
If the option for the duplexer still does not appear, verify that the following conditions
exist:
●
The duplexer is attached to the printer.
● The duplexer is enabled in the printer software.
● The media type and size selected on the Paper/Quality tab are supported by the
duplexer.
For a list of supported media types and sizes, see the specifications for the duplexer:
–
Automatic Two-Sided Printing Accessory
– Auto Two-Sided Print Accessory with Small Paper Tray
Only one side of the page prints when the two-sided printing option is enabled
Verify that the following conditions exist:
●
The correct print options are set in both the printer software and the software
program that you are using.
● The photo paper is not curled, if you are printing on two-sided photo paper. Photo
paper should be flat before printing. See
storing and handling photo paper for more
information.
● If the media type or size is not supported by the duplexer, you can print the document
by using the
manual two-sided printing instructions .
The media type and size that is selected on the Paper/Quality tab are supported
by the
duplexer .
Note Do not try to print a two-sided document on single-sided paper, such
as single-sided photo paper.
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