Brother DCP-J552DW Service Manual page 153

(24) The head/carriage unit is assigned a property code which indicates the unit's properties. This
code is encoded in the QR code label affixed to the head/carriage unit and the bar code label
affixed to the lower cover.
When you remove the head/carriage unit and store it separately from the machine, remove the
property label (bar code label) from the upper cover and store it together with the head/carriage
unit.
Assembling Note If you replace the head/carriage unit, attach the property label (bar code
label) that comes with the new head/carriage unit to the upper cover as shown below.
Property code (13 digits)
Head property label
(QR code)
Head/carriage unit
3-36
(3_044)
Confidential