Brother GTX600NB Instruction Manual page 202

(10) Unlock the print head, and remove the print head.
<IMPORTANT>

When removing the print head, be careful not to drip the ink on the carriage plate. If the ink is dripping, wipe off the dripping
ink.
(11) Release the lock by pulling part (a) on the case to the left and take out the new print head from its case.
<IMPORTANT>

When removing the print head, be careful not to touch the nozzle surface at the bottom of the head. Otherwise it may cause
poor printing.
<TIPS>

Sometimes, you may find it hard to remove the print head when you try to open the lock of (a) part. If it is hard, use both
hands to remove it.
(a) part
(12) Mount the new print head onto the carriage and push in the lock bar of the print head to lock the print head.
<IMPORTANT>

Be careful not to pinch the flat cable between the metal plate of the print head and the carriage.

Be careful not to let the metal plate of the print head ride on the positioning part.

Be careful not to touch the lock of the other head and release the lock.
Print head
Precautions to keep good printing quality/use printer over the long term
Lock
Remove
Print head
Case
6-34
Print head
Lock bar