Brother MFC4820C Service Manual page 55

[ 2 ] Structure of the print head unit
The print head unit consists of an ink jet head, manifold and air vent unit.
From the
needle tube
Print head units also have their own individual properties. When a unit is installed in the machine,
its property data is stored in the EEPROM on the driver PCB.
A property label, on which a property code is printed, is attached to the print head unit itself as
well as on the rear left side of the machine. If you replace the print head unit with a new one, you
need to enter a property code (14-digit) into the EEPROM in the maintenance mode (Function
code 68) and replace the property label with the one that comes with the new unit.
(1) Print head unit
This machine uses drop-on-demand ink jet printing. The print head has two ink-jet units for the
four colors of ink. Each of these units consists of 75 nozzles, 75 channels coated with piezoelectric
ceramic (PZT), a manifold and a filter. As illustrated below, each pair of nozzle columns is
staggered.
Manifold
Ink jet head
Carriage travel direction
13.039 (154/300")
0.1693 (1/150")
#1
2
3
4
71
72
73
74
#75
Black Cyan Yellow Magenta
Ink-jet units
Nozzle Layout (as viewed from the bottom)
Print Head Unit
Property code
(14-digit)
0.3387 (1/75")
Paper feed direction
4 -1 4
Air vent unit