Dell Colour Laser Printer 3110cn, Service Manual

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Chapter 6 Principles of Operation
Version 2 2006.04.05
5.5 Color Registration Control
The printer uses a tandem system where the drums and developers are arranged respectively for each
of yellow, magenta, cyan, and black colors. Since the images are formed on the drum of each color to
be overlayed one another, a color shift may occur. The color registration control calculates how much
the registration is shifted, and adjusts the PRINTHEAD 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 on the Belt, the output value of ADC Sensor is measured to determine the
threshold value.
2) The patches for color registration control are generated on the Belt. These patches are
composed of 10mm lines of K, C, K, M, K, and Y in this order.
3) The density of patches generated by the ADC Sensor is read.
4) The shift correction amount is calculated from the threshold value determined in 1) and the patch
density measured in 3).
5) The PRINTHEAD write timing is changed according to the shift correction amount.