2-56 Phaser 6280 Color Laser Printer Service ManualTheory of OperationColor Registration ControlThe printer uses a tandem electro-photographic system with Organic PhotoConductor (OPC) Drums and direct transfer by the Transfer Belt. The imagesare formed on the Drums of respective colors and they are overlapped to formone image, and in this case, a color shift may occur. The color registrationcontrol calculates how much the registration is shifted, and adjusts the LaserUnit write timing.The scan control adjusts all four colors in the process direction.The color registration control is made from a change in inside temperatureand the print count at the execution of the process control. This control isoutlined as follows:1. With no toner on the Transfer Belt, the output value of the ADC Sensor ismeasured to determine the threshold value.2. The patches for color registration control are generated on the Belt.These patches are composed of 10 mm lines of K, C, K, M, K, and Y inthis order by the amount of four dispense counts, led by a black trigger.3. The ADC Sensor reads the patch density.4. The adjusting amount of registration shift is calculated from the thresholdvalue determined in step 1 and the patch density measured in step 3.5. The Laser Unit write timing is changed from the adjusting amount ofregistration shift.10 mmAbout One HalfTurn Of BeltColor Registration ControlKKCKMKY
