If you are using hp-toolbox from Hewlett-Packard and the HP print 
drivers, somewhere during the SL7x upgrade/maintenance chain (including 
subsidiary application), the print driver appears to "break".  I used 
the hp-toolbox GUI and had to install new plugins from HP for this 
application.  After that, the HP printer (connected via USB to a SL 7x 
Linux workstation) again printed.

Yasha Karant