Brother GTX-4 Instruction Manual page 28

No. Name
12 Carriage fixing pin
To prevent drying of print heads in an emergency such as a blackout, it
fixes the carriage to the cap position of the maintenance unit.
Refer to "4-2-3. When there is no prospect of electric power recovery for a
while due to power outage >>P.43".
28
Name and function of each component
Function