Brother DCP-4020C - Manual (Page 39)

4 - 4 INITIAL SETUP
Power Save
Setting Power Save Mode reduces power consumption by turning off
the CPU etc. inside the machine. If Power Save Mode is switched
ON , when the machine is idle for approximately 10 minutes, it drops
into power save mode automatically.
The machine will display SLEEP instead of the date and time.
1
Press Menu/Set , 1 , 5 .
2
Press to select ON (or OFF ).
Press Menu/Set .
3
Press Stop/Exit .
GENERAL SETUP
5.POWER SAVE