i am using Xerox workcenter 7120 but there in no option to change the prefrences black and white as default printing in MAC OS X.
Plaese suggest how to set as default printing for black and white in mac
You need to enable CUPS on a Mac if you want to set preferences. Once you do that it is pretty simple
Just go into cups with a webbrowser ala 127.0.0.1:631
Select Printers(1) then the 7120 queue(2) at the left
Choose Set default options in the dropdown
Then select Image Options(1) and set Xerox Black and white to On (2)