Canon QY8-1360-000 4-47, BJC-7100, Part 4 Technical Reference, Purge sensor, Paper end sensor

BJC-7100 Part 4: Technical Reference

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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