Dell 5110cn Color Laser Printer Service Manual - Page 569

Chapter 6 Principles of Operation 5.5 Color Registration Control The printer uses a tandem system where the drums and developers exclusively for yellow, magenta, cyan, and black are arranged respectively. The images are formed on the drums of respective colors and they are overlapped to form one image, and in this case a color shift may occur. The color registration control calculates how much the registration is shifted, and adjusts the PRIINT HEAD write timing. The lateral registration control adjusts all of four colors in lateral directions. The color registration control is made from a change in inside temperature and the print count at the execution of the process control. The control is outlined below: 1) With no toner put on the BTR, the output value of AUTOMATIC DENSITY CONTROL SENSOR is measured to determine the threshold value. 2) The patches for color registration control are generated on the BTR. These patches are composed of 10mm lines of K, C, K, M, K, and Y in this order by the amount of four dispense counts, led by a black trigger. 10mm K K C K M K Y About one turn of BTR engine principle0045FA 3) The density of patches generated by the AUTOMATIC DENSITY CONTROL SENSOR is read. 4) The adjusting amount of registration shift is calculated from the threshold value determined in 1) and the patch density measured in 3). 5) The PRINT HEAD write timing is changed from the adjusting amount of registration shift. 6 - 50