Follow the instructions below:

1. Turn off the printer.


2. Press and hold the Pause button, and then turn on the printer.


3. For the Black Mark Sensor
   Release the button when the LED is lit in green/amber (5 times) after the green LED blinks five times alternately.
   
   For the Gap Sensor
   Release the button when the LED is lit in red/amber (5 times) after the green/amber LED blinks five times alternately.