Opensuse 12.3 - Which printer driver(s)/module(s)/xxxx is used by the system

Hello.
I am using two network laser printers on my local network.
Printing is done through CUPS.
I have install each drivers with zypper.
I would like to know how to find what software/driver/module is used by the system so I can verify if something is missing.
lsmod seems not helping.