By default, Windows 7 will inform you when you have successfully printed to a network printer. If you also think this information has no value, here’s the procedure to disable it.
To disable it, go to Start – Devices and Printers. Next, select a network printer so the menu bar will show you Print server properties - click on it.
Inside the appearing window, go to the Advanced tab and deselect Show information notifications for network printers.
In case you’re an administrator and would like to disable this message for all of your users, set the registry value HKEY_CURRENT_USER\Printers\Settings\EnableBalloonNotificationsRemote to 0 (REG_DWORD).