Detection Function; Hp Sensor; Paper End Sensor; Delivery Sensor - Canon BJC-55 Service Manual

Part 4: Technical Reference

5. DETECTION FUNCTION

The printer uses HP sensor, paper end sensor, delivery sensor, inside temperature sensor,
and head temperature sensor. Also, the capacity of the waste ink absorber is stored in the
EEPROM. When the absorber is about to become full a warning is given and when full an
error will occur. The printer detects the level of the ink remaining in the ink cartridge by
counting the number of dots ejected, and indicates when the ink runs out. The ink
remaining detection function operates only when the setting for the BJ controller is ON.

5.1 HP Sensor

The photointerrupter type HP sensor detects the edge of the carriage in order to detect
the carriage position.
After the carriage senses the edge, it moves to the right, and the print head is capped at
its home position.

5.2 Paper End Sensor

The switch type paper end sensor detects the presence of paper.

5.3 Delivery Sensor

The switch-type sensor detects whether paper has been delivered.

5.4 Temperature Sensor

The temperature sensor on the control board detects the temperature inside the
printer. The ASIC detects a change in the thermistor resistance that changes along
with changes of the inside temperature. The ASIC converts the input analog value,
which is a voltage converted from the thermistor resister to a digital value with the
internal A/D converter. This value is used to control the pulse width of the head drive
control signal and temperature adjustment signal.

5.5 Head Temperature Sensor

The head temperature sensor in the print head detects the head temperature. The
ASIC detects the diode sensor that changes as a change in voltage along with changes
in the head temperature. The ASIC converts the input analog value to a digital value
with the internal A/D converter. When the head temperature rises excessively, the
digital value becomes large, which can stop ejecting the ink from the head.
Paper End Sensor
HP Sensor
Figure 4-31 Sensor Location
4-44
TH1
Delivery Sensor
BJC-50