Planetary Arm; Bevel Gear; Tube Pump; Head Caps - Brother MFC640CW Service Manual

- Planetary arm

This switches power to the tube pump and pump switching unit depending on the direction of
paper feed motor rotation.

- Bevel gear

This transmits the power from the clutch gear to the planetary arm.

- Tube pump

A roller squeezes the ink drain tubes looped inside, forcing their contents toward the ink absorber
box and creating negative pressure.

- Head caps

When the power is off or there is no printing, these fit tightly over the print head to prevent the
head nozzles from drying up and to seal the head nozzles for purge operations to suck up old ink.
- Air vent rods
Pushing these up opens the shut-off valves inside the air vent unit, expelling air trapped in the
manifolds.
- Head wiper
As the head/carriage unit moves, this wipes off any ink remaining on the head nozzle surface.
- Head cap holder
This moves to the right together with the head/carriage unit as the latter returns to its home
position. Rightward motion of the head cap holder turns the lift arms, fitting the head caps tightly
over the print head to seal the head nozzles.
Head cap unit
Head wiper
Viewed from the top
Pump switching unit
Air vent unit
Switching arm
Head cap
assembly
holder
Head lock
3-25
Purge cam
Purge bevel gear
Viewed from the bottom
Tube pump
Confidential