Carriage System - Canon WS8400 Service Manual

2.5.3 Carriage system

Carriage cover sensor
The photo interrupter-based carriage cover sensor detects opening and closing of the carriage cover.
When the carriage cover is closed, the sensor light is cut off by the sensor arm, and this notifies the sensor that the carriage cover is closed.
Carriage home position sensor
The photo interrupter-based carriage home position sensor detects the carriage home position.
The sensor, located on the right-side plate, detects the sensor flag on the carriage unit by controlling the movement of the carriage.
The carriage home position is defined based on the location where the sensor flag is detected.
Linear encoder
The linear encoder, installed on the rear of the carriage, detects the position of the carriage using the slits on the linear scale while the carriage is moving.
Registration sensor
The photo reflection-based registration sensor detects media skewing, media width, and media misalignment. The sensor detects the edges by monitoring
the change in voltage with respect to changes in the reflection density from the media.
Print head position H sensor (H)/(L)
The print head position H sensor (H)/(L) located on the right-side of carriage unit detects the position of the print head height adjustment lever (3 positions).
Environment temperature sensor
The environment temperature sensor (thermistor) installed on the head relay PCB detects the environment temperature in the vicinity of the carriage.
The resistance measured by the thermistor, which varies as the temperature inside the printer changes, is sent to the engine controller after passing through
the carriage relay PCB.
The environment temperature is used to calibrate the head temperature sensor and to detect abnormal internal printer temperatures.
Head temperature sensor
A set of two diode head temperature sensors are installed at the top and bottom of the nozzle arrays of printhead to detect the temperature of the printhead.
The voltage produced by each diode, which varies as the temperature near the nozzle array changes, is sent to the engine controller after passing through
the carriage relay PCB.
The head temperature information is used to control the operation of the head and to detect abnormal head temperatures.
Printhead contact detection
The status of direct contact between the contact faces of the printhead and the carriage is checked by testing the electrical conductivity.
The contact status between the two faces is detected from the voltage changes of the flexible cable connecting two separate terminals on the contact surface
of the printhead, the power supply terminal, and the GND terminal.
Head relay PCB
Carriage cover sensor
Linear scale
Linear encoder
Print head position
H sensor (H)
Print head position
H sensor (L)
Registration sensor
F-2-43
Carriage home
position sensor
Chapter 2
0008-3883
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