Konica Minolta bizhub C451 - Manual (Page 306)

Function detail description 9
C451 9-9
When “Confidential Document Access Method” is set to “Mode 1”
1
Press the [User Box] key in the control panel of this machine, and then
touch [Use Document].
– If the Application Menu appears, press the [User Box] key.
2
Select [System User Box], touch [Secure Print User Box], and then
touch [OK].