Accepting Only Encrypted Secure Printing
You can set the machine to only receive encrypted secure print jobs from computers.
This setting can be specified when the Encrypted Secure Printing function is available for use. For information on the optional products required to use the Encrypted Secure Printing function, see "Optional Products Required for Each Function."
1.
Press 
(Settings/Registration).
(Settings/Registration). 2.
Press [Function Settings] → [Secure Print] → [Only Allow Encrypted Print Jobs].
3.
Press [On] → [OK].
If you do not want to restrict print jobs, press [Off].