Service manual
Principles of Operation
Home position sensor
The home position sensor switch is on when the carriage is at the home position.
This sensor determines the reference position for the carriage drive. Figure 2-4
illustrates the home position sensor.
Home position
+
on
+
LOW level
Other position
+
off
+
HIGH level
Figure 2-4. Home Position Sensor
Thermal sensor
The thermal sensor in the printhead monitors the printhead’s temperature. If the
temperature exceeds a predetermined upper limit, the printer stops printing until
the temperature drops to a predetermined value. ‘Then printing resumes. Figure
2-5 illustrates the thermal sensor circuit.
Figure 2-5. Thermal Sensor
LQ-200/AP3000
2-5