Brother MFC5490CN - Sensors and Actuators

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3.2.3 Sensors and Actuators
This machine uses the following sensors and thermistors.
• The document front sensor detects whether there is a document in the ADF.
• The document rear sensor detects the leading and trailing edges of document pages, indicating
to the control circuitry the point at which to start reading and when page scanning is complete.
• The scanner cover sensor detects whether the scanner cover (scanner unit) is properly closed.
• The ink cartridge cover sensor detects whether the ink cartridge cover is properly closed.
• The registration sensor detects the leading and trailing edges of paper for use in determining
print start and end timings and detecting paper jams.
• The paper width (media) sensor checks whether recording paper is A4 or greater in width at
the start of recording of FAX data received. With this sensor signal, the controller prevents the
print head from printing on the outside of paper in borderless printing. It also protects the
platen from no-paper printing when a paper jam occurs, preventing stains on the platen and
the back side of paper.
• The head thermistor detects the temperature inside the head/carriage unit. According to the
sensor information, the controller adjusts the head driver to compensate for changes in ink
viscosity.
Sensor Name
Sensor Type
Location
Document front sensor Photosensor
On the document front sensor PCB in
the ADF unit
Document rear sensor Photosensor
On the document rear sensor PCB in
the ADF unit
Scanner cover sensor Carbon switch
On the control panel PCB
Ink cartridge cover sensor Carbon switch
Registration sensor Photosensor On the registration sensor PCB
Paper width sensor (media sensor) Photosensor
On the carriage PCBHead thermistor Thermistor
CR encoder sensor Photosensor
PF encoder sensor Photosensor On the PF encoder PCB
ASF encoder sensor Photosensor In the ASF motor unit
Purge cam switch Mechanical switch
On the maintenance unit
Cap lift cam switch Mechanical switch
Casing internal temperature thermistor Thermistor
On the ink empty sensor PCB inside
the ink refill assembly
Ink empty sensors (four) Photosensor
Ink cartridge detection sensors (four) Photosensor
On the ink cartridge detection sensor
PCB on the ink refill assembly