Now all you have to do is go to System > Administration > Printing > Select local printer
your lexmark 4200 series should be listed.
Ok select Forward.
Now select the correct driver:
Model: LEXMARK Z42
Driver: High Quality Image (GIMP-Print)
now, turn off your printer. Disconnect the power cable a reconnect it again. turn power on.
You are ready to print.
Now in the ubuntu printing utility your new printer "LEXMARK Z42″ should be listed. right click on it and from the pop up menu select properties.
Now you can change the printer resolution. Default is 300 Dpi which is excellent for quick prints and to save ink. If you want a good resolution but you don't want to waste to much ink i will recommend set it up on 600 dpi high quality.