CUPS, by default, disables printout to a printer if the printer stops responding. In order to re-enable printing, you must go into YaST | Hardware | Printers and for the disabled printer, select the "Printout Enabled" checkbox.
To prevent a printer from becoming disabled in the first place, as root, open /etc/cups/printers.conf. For each printer, change the ErrorPolicy line from "stop-printer" to "retry-job". CUPS will now retry the job every 30 seconds.
If you want to change the time it takes before it retries, open /etc/cups/cupsd.conf and add a line (or edit, if it already exists) that says "JobRetryInterval 120", where 120 is the time in seconds.