Brother MFC-9420CN Service Manual page 185

(3) To release the fusing unit from the machine, release the lock levers that are on both sides of
the fusing unit.
Lock lever
(4) Hold the handles on both sides as you take the fusing unit out of the machine.
Fig. 6-10
Fig. 6-11
6 -1 0
Lock lever
Fusing unit
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