Sensors And Actuators - Brother MFC5490CN Service Manual

3.2.3 Sensors and Actuators

This machine uses the following sensors and thermistors.
Sensor Name
Document front sensor
Document rear sensor
Scanner cover sensor
Ink cartridge cover sensor
Registration sensor
Paper width sensor (media sensor)
Head thermistor
CR encoder sensor
PF encoder sensor
ASF encoder sensor
Purge cam switch
Cap lift cam switch
Casing internal temperature thermistor
Ink empty sensors (four)
Ink cartridge detection sensors (four)
• 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 Type
On the document front sensor PCB in
Photosensor
the ADF unit
On the document rear sensor PCB in
Photosensor
the ADF unit
Carbon switch
On the control panel PCB
Carbon switch
Photosensor On the registration sensor PCB
Photosensor
Thermistor On the carriage PCB
Photosensor
Photosensor On the PF encoder PCB
Photosensor In the ASF motor unit
Mechanical switch
On the maintenance unit
Mechanical switch
Thermistor
On the ink empty sensor PCB inside
the ink refill assembly
Photosensor
On the ink cartridge detection sensor
Photosensor
PCB on the ink refill assembly
3-47
Location
Confidential