HP Deskjet 6540 Color Inkjet Printer - Manual (Page 152)

For the system requirements, see the reference guide that came with the
printer.
2. Make space available on the hard drive by deleting unneeded files.
Printer is in ink-backup mode
The printer might print more slowly if it is in ink-backup mode .
To increase the print speed, use two print cartridges in the printer.
15.12 If you continue to have problems
If you continue to have problems after investigating the troubleshooting topics, turn
off and then restart your computer.
If you still have problems after restarting your computer, go to HP customer support
at www.hp.com/support .
HP Deskjet 6500 series printers User's Guide
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