HPLIP was upgraded a day or two ago to version hplip-3.13.5; it cures some ills.
You can download the source from http://prdownloads.sourceforge.net/h...-3.13.5.tar.gz
(or start at http://hplipopensource.com/hplip-web/gethplip.html
and click on the link to the above at the bottom of the page, "Advanced users may wish to download the HPLIP tar package
. (Download Tarball Digital Certificate) What's this?" or, maybe, get it from current
(not sure about that one).
Once you've got the source, use the HPLIP SlackBuild from the distribution source CD/DVD to build the package then upgradepkg hplip-3.13.5-x86_64-1.txz
Might go a long way toward fixing glitches.
Hope this helps some.