In this machine, the mechanism that makes the laser unit operational is a 24V line interrupted using a 5V relay, and then 24V is dropped to +5V using a regulator. To ensure the safety of the machine operators and service technicians, six switches prevent the laser beams from switching on accidentally. When either the right door, left door, or front upper cover is opened, the +5V line connecting the LD driver on the LD control board is disconnected to disable the laser unit.