I just have added a Lexmark Optra S 1250 printer as a network printer; this being the first and only printer installed on a recently updated Ubuntu 12.04.1.
Installation of the drivers went very smooth after I entered the IP address. But when I print something, anything, a test page or a document from Libre Office, the printer makes 10 copies of each page. I checked that it truly says 1 copy in the printer options, as well at printing options within the application.
At driver installation I chose the default options at any point, which all seemed to be correct. It installed as "Lexmark Optra S 1250 Foomatic/Postscript (recommended)".
