Operation Manual

Purge sensor
The purge sensor uses a transmission-type photointerrupter to detect the capping
position of the purge unit. When the flag on the cam gear in the purge unit interrupts
the purge sensor, the module phase is deemed to be in the capping position.
Paper end sensor
The paper end sensor uses a transmission-type photointerrupter to detect the presence
of paper in the paper feed system. When the paper presses against the paper end
sensor arm, the paper end sensor is interrupted, indicating that paper has been picked
up by the paper feed system.
Pickup roller sensor
The pickup roller sensor uses a transmission-type photointerrupter to detect the initial
position of the pickup roller of the sheet feeder. When the flag in the pickup roller
interrupts the pickup roller sensor, the pickup roller is deemed to be in the initial
position.
Home position sensor
The home position sensor uses a transmission-type photointerrupter to detect the
home position of the carriage. When the home position edge of the chassis interrupts
the home position sensor on the carriage board, the carriage is deemed to be in the
home position.
Printer temperature sensor
The thermistor on the carriage board detects the temperature inside the printer.
The printer fetches the voltage output by the printer temperature sensor. This voltage,
which varies according to the temperature, is converted from analog to digital to
determine the printer temperature. The temperatures detected by the printer
temperature sensor and the head temperature sensor are used to control the printer to
achieve optimum printing, and to prevent overheating.
The head temperature sensors are built into the heater boards of the
respective print heads. See Part 4, section 3.2.2, "Structure of BJ head unit"
(page 4-19) for details.
The printer decides if an error has occurred from the readings from the
various sensors. For details, see Part 3, section 3.1.2, "Service calls" (page 3-
15) .
The states of the purge sensor, paper end sensor, pickup roller sensor,
and home position sensor are detected by the MPU's input ports. The
detection signal is inverted according to whether the sensor is interrupted
or open.
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BJC-7100
Part 4: Technical Reference