Brother MFC990CW Service Manual page 259

Note: When storing the head/carriage unit for a long period, be sure to put a head joint
rubber and an air buffer cap on the head/carriage unit and store the unit in the head casing,
as shown below. Leaving the head/carriage unit out of the casing will cause the head
nozzles and ink supply ports to dry up, resulting in a damaged head.
Latch
Head casing (upper)
Air buffer cap
Head joint rubber
Head/carriage unit
Head casing (lower)
(6_64)
Assembling Note: After replacement of the head/carriage unit, make adjustments specified
in Chapter 7, Section 7.2. (For the head/carriage unit having a round, blue seal, perform the
head replacement purge; for the unit having no seal, perform the initial purge. See Section
7.2, [ 2 ].)
Blue seal
(head_blue_seal_BHM9)
6-75
Confidential