How do I add a user to Print Administrator group but not full administrator?
Run this Terminal command (as an administrator), replacing "usersaccountname" with the user's actual account name:

sudo dseditgroup -o edit -n /Local/Default -a usersaccountname -t user _lpadmin


When it prompts you, enter your password (it won't echo).  That user should now be able to administer printers.