Service manual

III-47
7.5 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 cyan, and black are arranged respectively. The images
are formed on the drums of respective colors registration control calculates how much
the registration is shifted, and adjusts the scanner write timing.
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 transfer roll cartridge, the output value of holder ASSY CTD
is measured to determine the threshold value.
2) The patches for color registration control are generated on the transfer roll cartridge.
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
About one turn of
Transfer roll cartridge
K
K
C
K
M
K
Y
Fig.3-47
3) The density of patches generated by the holder ASSY CTD 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 scanner write timing is changed from the adjusting amount of registration shift.