Brother MFC-4820C, Руководство по обслуживанию

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4.2.4 Sensors and Actuators
This machine has the following sensors and thermistors.
Sensor name Type Location
Scanner/ink slot cover open
sensor
Photosensor Control panel PCB
Registration sensor Photosensor
ASF switch Mechanical switch
ASF
Paper width sensor (Media
sensor)
Photosensor
Head flat cable of the
needle tube ASSY (set in
the print head unit)
Purge cam HP switch Mechanical switch Purge unit
Ink cartridge sensors (x 4) Photosensor Ink cartridge sensor PCB
Hook switch (on the MFC4820C) Mechanical switch
Hook switch PCB in the
handset
Air pump motor encoder sensor Photosensor Air pump & motor module
Carriage motor (CR) encoder
sensor
Photosensor
Head flat cable of the
needle tube ASSY (set in
the carriage)
Paper feed motor (PF) encoder
sensor
Photosensor
Casing internal temperature
thermistor
Thermistor
PF encoder PCB on the left
side of the engine unit
Head thermistor Thermistor Print head unit
• The scanner/ink slot cover open sensor detects whether the scanner unit and/or the ink slot
cover are closed.
• The registration sensor detects the leading and trailing edges of the paper, which allows the
controller to determine the registration timing and to check for paper jams.
• The ASF switch detects the switching timing of the forward/reverse direction of the ASF motor
rotation. If the ASF motor rotates in the forward direction, the paper stoppers lower to guide the
paper to the paper slot. If it rotates in the reverse direction, the ASF roller rotates to pull in
paper.
• The paper width sensor detects whether the paper width is "A4-size or wider" or "narrower than
A4-size."
• The purge cam HP switch detects whether the purge cam is in the home position or not.
• There are four ink cartridge sensors for four colors, each of which detects whether the
corresponding ink cartridge is ink-empty. When the optical path of the sensor is interrupted by
the sensor actuator built in the ink cartridge, the controller interprets it as ink present. As ink
remaining in the cartridge decreases, the sensor actuator comes out of the optical path and the
controller interprets it as ink empty. These sensors detect also whether ink cartridges are
loaded.
• The hook switch detects whether the handset is on the hook.
• The air pump motor encoder sensor monitors the rpm of the air pump motor (DC motor),
allowing the controller to accelerate or decelerate the motor using PWM control to produce
optimal positive pressure.