Canon PIXMA MX459 Online Manual page 35

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
The machine cannot send or receive faxes when the power is turned off.
The power cannot be turned off while the machine is sending or receiving a fax, or when unsent
faxes are stored in the machine's memory.