Back End; Back End Components And Their Main Roles; Damper Assembly; Air Vent Unit - Brother MFC640CW Service Manual

Back end

Back end components and their main roles

- Damper assembly

This has two roles: dampening the ink pressure fluctuations** in the tubes as the carriage moves
and collecting air bubbles that result from pressure changes on the ink.
** Ink pressure fluctuations: As the head/carriage unit travels, inertia means that the ink remains in the same
place, temporarily raising the pressure in the tubes.

- Air vent unit

At regular scheduled intervals, this vents any air bubbles that have accumulated in the damper
assembly.
- Air vent cap
This fits tightly over the air vent unit to allow the negative pressure from the pump to suck air
bubbles out of the unit.
- Air vent rods
These open air vent flow paths by pushing up the normally closed shut-off valves inside the air
vent unit.
Shutoff valve
Damper ASSY (Color)
Air vent rods
Damper ASSY (Black)
3-15
Air vent unit
(A part of head/carriage unit)
Air vent cap
(A part of maintenance unit)
Confidential