Canon MG6400 SERIES Online Manual page 106

Important
When you unplug the power cord after turning off the machine, be sure to confirm
that the POWER lamp is off.
Notice for Unplugging the Power Cord
Note
Auto power off feature
You can set the machine to automatically turn off when no operations are performed
or no print jobs are sent to the machine for a certain interval. This is the default
setting.
From the machine
About ECO settings
From the computer
Managing the Machine Power
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