Bad printing quality - samsung printer

Hi,
I have quite freshly installed Lubuntu 12.10 and have problem with quality of printing. My printer is Samsung CLX-3180 series, and it looks that it uses too much ink for printing.
When I print same document on computer with windows and my computer with lubuntu, the difference is really huge. On doc by Lubuntu normal text looks like bold.
Every options is on default and normal (I checked with win and it seems that the settings are set on the same values).
I have installed driver using this repository http://www.bchemnet.com/suldr/
My installed files are: samsungmfp-scanner, -network, -libmfp, -driver-4.00.39, -driver, -data, -common (all version 4.00.39-1) and also some default printer-driver-splix (I don't know which driver is currently used)
I used ubuntu before and printer worked fine, but I can't remember what driver I used. Scanner is working fine.
Do you have please any idea what should I try? I am quite new user, so terminal commands write in exact form. Thank you very much.

PS: Can you also please tell me where to set numlock to be automatically set ON after login? It's quite annoying to do it every time manually.