3 ] Head Capping Mechanism - Brother MFC640CW Service Manual

[ 3 ] Head capping mechanism

When the power is off or the machine is not printing, this mechanism fits the head caps tightly over
the print head to prevent the head nozzles from drying up and to keep dust off the print nozzle
surface.
The pump switching unit connects the spaces inside the caps to the atmosphere to prevent internal
pressure fluctuations due to environmental changes from damaging the meniscuses. The ink
remaining inside these spaces seals them. (See the illustration below.)
This mechanism moves with the head/carriage unit. When the head/carriage unit returns to its home
position, it presses against the head cap holder in the maintenance unit. The lift arms in the
maintenance unit raise the head caps, fitting them tightly over the head nozzle surface to protect
them.
Head/carriage unit
Head cap holder
Head cap unit
Lift arms
Print head
Head cap for black ink
Head cap for color ink
Black drain tube
Pump switching unit
Ink remaining in the tube
Color drain tube
Main drain tube
Ink remaining in the tube
Confidential
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