Brother MFC 685CW - Color Inkjet - All-in-One, Service Manual

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3-21
Confidential
Ink refill assembly components and their main roles
- Ink refill case
- Cartridge lock levers
- Ink refill base
- Ink tube joints
- Ink cartridge sensors (on the ink cartridge PCB)
- Ink absorber felts
Inserting the ink cartridges into the ink refill case and securing them with the cartridge lock levers
forces the cartridges' ink supply ports into close contact with the ink refill base to prevent ink
leakage.
The ink from the ink cartridges flows through the ink refill base into the ink supply tubes connected
to the ink tube joints. As the ink level in an ink cartridge drops, the pressure inside falls, drawing air
in the ink cartridge.
An ink cartridge sensor actuator blocking light to an ink cartridge sensor indicates that there is ink
in the ink cartridge. When ink runs low, the actuator moves out of the beam, activating the sensor
("Ink near-empty"). (Note that the firmware also interprets a missing ink cartridge as running low on
ink.)
At the back of and beneath the ink refill case are ink absorber felts that absorb any ink that leaks
from the ink cartridges, limiting its spread and thus reducing the risk of damage to other components.
[ 6 ] Ink supply tubes
These are made of an elastomer providing a highly impermeable barrier against air ingress and
drying out of the ink during extended periods of nonuse. This material is also soft and highly
flexible to better withstand the sharp and frequent bending associated with high-speed head
operation repeatedly over extended periods.