Reference :
http://www.eggheadcafe.com/community/aspnet/3/10015411/prevent-printing.aspx
prevent printing
As there are many ways of accessing a web page - through custom browsers & programmatically, preventing user from printing text from a web page is not possible. Moreover, they can also print the screen. Any Javascript code to prevent printing by hiding the toolbar options, context menu and through the keyboard will not
function if Javascript is disabled through browser preferences.
While printing cannot be absolutely prevented it can be made harder. The script to disable any key can be adapted from the article here - http://www.alphafilter.com/?inc=article&aid=69
This CSS trick will prevent user from printing content without disabling any print options & is a very good deterrent:
< style type=""text/css"" media=""print">
BODY {display:none;visibility:hidden;}
< /style >