Printer initialisation clears the printer's DRAM and restores its factory settings.
To activate printer initialisation, do the following:

1. Turn off the printer.


2. Press and hold the Feed/Pause Button and then turn on the printer.


3. Release the button when the LED is lit in green (5 times) after the amber LED flashes five times.
   The LED colour will change in the following order:
   Amber > Red (5 times) > Amber (5 times) > Green (5 times) (Release the button here) > Green/Amber (blinks 5 times alternately) > Red/Amber (blinks 5 times alternately) > Green (lit)
   
   After the initialisation, the printer will be reverted to its factory settings:

   Parameter	Default setting
   Speed	(TD-4420TN) 76 mm/sec (3 ips) (203 dpi)
   	(TD-4520TN) 76 mm/sec (3 ips) (300 dpi)
   Density	8
   Label Width	101.5 mm (4")
   Label Height	101.5 mm (4")
   Sensor Type	Gap sensor
   Gap Setting	3 mm (0.12")
   Print Direction	0
   Reference Point	0,0 (upper left corner)
   Offset	0
   Tear Mode	On
   Label Peeler off Mode	Off
   Cutter Mode	Off
   Code Page	850
   Country Code	1
   Clear Flash Memory	No

    

   You can also calibrate by using the BPM (Brother Printer Management Tool).