Brother MFC-3820CN - Manual (Page 115)

10 - 3 MAKING COPIES
Using the Copy keys
(Temporary settings)
When you want to change the settings only for the next copy, use the
Temporary Copy keys. You can use different combinations.
These settings are temporary, and the MFC returns to its default
settings 60 seconds after it finishes copying. If you want to use these
temporary settings again, place the next original in the ADF within
that time. However, if you have set the Mode Timer for copy and
Scan modes to 0 or 30 seconds, the MFC returns to the default
settings after the number of seconds that has been set for mode
timer. (See Setting the Mode Timer on page 4-5.)
Temporary Copy keys