Brother MFC260C Service Manual page 70

Ink cartridge components and their main roles
- Disc valve S
A plastic needle in the refill base opens this valve to supply air to the ink cartridge. Removing
the ink cartridge closes this valve to prevent leakage due to ink backflow.
- Disc valve D
A plastic needle in the refill base opens this valve to allow ink to flow out of the ink cartridge.
Removing the ink cartridge closes this valve to prevent leakage.
- Sensor actuator
This actuator indicates the amount of ink remaining. Certain positions cut the light beam to the
ink cartridge sensor on the ink cartridge PCB inside the ink refill assembly.
Filled with ink
Sensor actuator
Ink cartridge sensor
These ink cartridges are single-use affairs. There is no provision for refilling them. The design
reduces environment load by using no metals and only burnable materials yielding no toxic
substances.
Ink near-empty detection
The ink refill assembly has four ink cartridge sensors (photosensors of transparent type) that
monitor the ink levels with sensor actuators inside the ink cartridges.
Attached to one end of the sensor actuator is a float. When there is ink in the cartridge, buoyancy
lifts the float, rotating the sensor actuator about a pivot near the center of the actuator to block the
light beam to the sensor, indicating that there is ink. As the ink level in the ink cartridge drops,
however, the float falls, eventually moving the sensor actuator out of the beam.
Light hitting the sensor is the signal that ink is running low ("Ink near-empty"), activating a firmware
counter tracking ink usage during ink-jet printing, purges, and other operations. When this counter
reaches a predetermined limit, the firmware considers the "ink empty" and prompts the user to
replace it.
Ink near empty
No ink cartridge loaded
3-19
(InkCartridgeSensor)
Confidential