Brother GT-782 Instruction Manual page 102

7. Troubleshooting
(12) Rotate the tube connector 90 degrees as shown below.
(13) Disconnect the tube and put the tube fitting removed from the new Print Head to prevent the ink from coming out.
(14) Turn the lever to the direction of the arrow to unlock the Print Head.
Lever
(15) Take off your gloves and remove the used Print Head by lifting up the knob.
Knob
93 GT-782