Canon BJC 6000 - Color Inkjet Printer Service Manual

Part 4: Technical Reference BJC-60004-425. DETECTION FUNCTIONS5.1 Detection with SensorsThis printer has the following sensors detect the printer's status.5.1.1 Home position sensorThis photointerruptor-type sensor detects the chassis' home position edge andcapping position edge to find the carriage's position. When the carriage finds thecapping position edge, the printer confirms capping and locks the carriage. Thecarriage uses the position detected by the home position edge as the reference todetermine its home position.5.1.2 Paper end sensorThis photointerruptor-type sensor uses its flag to check for the end of the paperpassed through the paper feed unit to determine if there is paper. If there is no paper,the paper sensor arm closes the sensor; if there is paper, it opens indicating thatthere is paper.5.1.3 Print position sensorConsists of a red LED and photosensor, and sees the reflection density of the printingpatterns, each printed slightly displaced from one another vertically and horizontallyfor each printing mode. The voltage varying with the reflection density is fed into theMPU as an analog input which is converted into a digital value by the built-in A/Dconverter. Based on the calculated compensation value, the printer performs optimumprinting position correction for both heads and for bi-directional printing. Be carefulnot to open the front cover during measurement, as external light may make accuratemeasurement impossible. For more on automatic printing position compensation,refer toPart 4: 2.3 Automatic Printing Position Alignment Function (page 4-15).Internal TemperatureSensorInk SensorCover Sensor Paper End SensorPump SensorHome Position SensorPrint Position SensorFigure 4-35 Sensor Positions