Does printer support scanning?

Is the printer in an error state? Run hp-check and verify in the installed printer queues section that the communication is "Good".

Run hp-check and verify that there are no errors.

Check hp-check -t that "scanner-build=yes

Verify that sane is configured with hpaio--run:

    export SANE_DEBUG_DLL=128

    scanimage -L

The printer should be detected.

View /var/log/syslogwhile scanning for any errors.  Depending on your distro you can run either; su -c "tail -f /var/log/syslog" or sudo tail -f /var/log/syslog, then try scanning and view the syslog for errors.

Is the user part of the scanner group? Run groups and verifiy. If not consult your Linux distro documentation on how to add the user to the scanner group.   In most distros you can run (as root): usermod -g scanner yourusername