Hitachi IJ UX Service Manual page 204

６ Remove the shutoff valve.(MV9)
(Refer to 5.5 Replacement
of shutoff valve)
７ Remove the 4 fastening screws
of the heating unit.
Remove the rear cover (8 screws)
８ Remove the connector and remove
the heating unit.
９ Prepare a new heating unit and put an O-ring1.7 in the terminal area
of the ink-supply tube(E).
Perform the assembly after dipping the O-ring in makeup, and
confirm that the O-ring does not jump out of the hole.
10 Attach the heating unit.
Heating unit
5-10
ＭＶ9
Heating unit
Connector