Canon BJC-55 Service Manual

5. DETECTION FUNCTIONThe 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 theEEPROM. When the absorber is about to become full a warning is given and when full anerror will occur. The printer detects the level of the ink remaining in the ink cartridge bycounting the number of dots ejected, and indicates when the ink runs out. The inkremaining detection function operates only when the setting for the BJ controller is ON.5.1 HP SensorThe photointerrupter type HP sensor detects the edge of the carriage in order to detectthe carriage position.After the carriage senses the edge, it moves to the right, and the print head is capped atits home position.5.2 Paper End SensorThe switch type paper end sensor detects the presence of paper.5.3 Delivery SensorThe switch-type sensor detects whether paper has been delivered.5.4 Temperature SensorThe temperature sensor on the control board detects the temperature inside theprinter. The ASIC detects a change in the thermistor resistance that changes alongwith 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 theinternal A/D converter. This value is used to control the pulse width of the head drivecontrol signal and temperature adjustment signal.5.5 Head Temperature SensorThe head temperature sensor in the print head detects the head temperature. TheASIC detects the diode sensor that changes as a change in voltage along with changesin the head temperature. The ASIC converts the input analog value to a digital valuewith the internal A/D converter. When the head temperature rises excessively, thedigital value becomes large, which can stop ejecting the ink from the head.Part 4: Technical Reference BJC-504-44HP SensorTH1Delivery SensorPaper End SensorFigure 4-31 Sensor Location