Supress Printing Message while printing

I assume the message is coming from the printer device driver. If so then there is probably not an easy way to supress it. Try finding the priner device driver documentation, but I have no idea where to look. An alternative would be to send the data to another computer such as the network server and print from there. Sure, that would be more work than you want to do, but it might be the only way. You are trying to hide something from the user of the computer. If the user is not the owner and the owner wants you to hide something from the user then you should be able to do that but it is likely not easy to figure out.
 
Windows has something called Policies; there might be a policy for that. Except a policy would probably apply to all printing so I assume that would not help.