Brother MFC-4820C, Руководство по обслуживанию

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4-16
Role as an air damper
The air in the upper section of the manifold also functions as an air damper that dampens the
dynamic pressure of ink in the needle tubes produced by the moment of inertia when the carriage
travels.
Without the air damper, the dynamic pressure of ink will directly affect the volume of ink output
from the ink jet head, resulting in lowered print quality.
(3) Air vent unit
When ink is supplied to the print head unit, air bubbles may be produced or air that was in the
tubes during an initial purge may have become bubbles in the ink. Such air bubbles may be
expelled through the air vent unit together with the surplus ink when positive pressure is applied.
The structure of the air vent unit is shown below. When the carriage reaches the purge position,
the four vent rods in the purge unit will pop up to push up the corresponding release rods in the air
vent unit which in turn will release the four shutoff valves.
The air vent is located slightly lower than the top of the manifold so that the correct amount of
damper air will be left. (For details on driving the vent rods in the purge unit, refer to Section
4.2.3.3, "Purge mechanism.")
The vented air and ink will be expelled into the drained ink reservoir by the pump in the purge
unit.
Drained ink reservoir
Manifold
Apply positive
pressure.
Ink jet head
Head cap unit
Pump
Air vent
Pushing up the
release rods releases
the shutoff valves.
Air vent rods
Release rods
Vent conduits
Shutoff valves
Air vent unit
Vent rod unit