Brother MFC-J3520 Service Manual page 239

(3) Release the four Hooks on the Platen and remove the Paper ejection roller from
the Platen.
(4) Remove the three Platen springs from the Platen.
Assembling Note:
Hooks
Paper ejection roller
The two Platen springs at the both ends may be mounted more inside
from the ones indicated in the illustration below depending on the model
and production year.
Mount them to the original positions.
Fig. 3-143
3-119
Platen spring
Platen Platen spring
Hooks
Confidential