Color Registration Control - Xerox Phaser 6130 Service Manual

Theory of Operation

Color Registration Control

2-40
The printer uses a tandem electro-photographic system with Organic Photo
Conductor (OPC) Drums and direct transfer by the Transfer Belt. Because the
images are formed on the individual Drums of the respective colors and then
overlapped to form one image, a color shift may occur. The color registration
control calculates how much the registration is shifted, and adjusts the Laser
Unit write timing.
The scan control adjusts all four colors in the process direction.
The color registration control is made from a change in inside temperature
and the print count at the execution of the process control. This control is
outlined as follows:
1. With no toner on the Transfer Belt, the output value of the 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 10 mm lines of K, C, K, M, K, and Y in
this order by the amount of four dispense counts, led by a black trigger.
10 mm
About One Half
Turn Of Belt
3. The ADC Sensor reads the patch density.
4. The amount of registration shift is calculated from the threshold value
determined in step 1 and the patch density measured in step 3.
5. The Laser Unit write timing is changed according to the amount of
registration shift.
K
K
C
K
M
K
Y
s6180-290
Phaser 6130 Color Laser Printer Service Manual