Registration Control (Color Shift Correction) System - Konica Minolta bizhub C250 Service Manual

Theory of operation ver. 3.0 Aug. 2006
8.2.6

Registration control (color shift correction) system

• In a tandem engine, in which an independent image reproduction process is provided for
each of the four different colors of toner. Incorrect color registration, or color shift, is
therefore more likely to occur due to each of the PH assemblies being out of correct posi-
tion. The color shift correction system automatically detects any misalignment among the
different colors, correcting it both in the main scanning and sub scanning directions.
• The color shift detection sequence proceeds as follows. A detection pattern each in the
main scanning direction is produced at the front and rear on the transfer belt. Each of
IDC/registration sensor/1 and /2 at the front and rear reads the corresponding pattern.
The amount of color shift in the sub scanning direction is then calculated and stored in
memory. A detection pattern each in the sub scanning direction is next produced at the
front and rear on the transfer belt. Each of IDC/registration sensor/1 and /2 at the front
and rear reads the corresponding pattern. The amount of color shift in the main scanning
direction is then calculated and stored in memory. Based on the data representing the
amounts of color shift, the machine calculates how much each of the different colors
should be corrected. The correction data is further stored in memory. Based on the data
stored in memory, the machine controls each dot during production of image outputs,
thereby correcting the color shift (varying the timing at which the LD is turned ON).
• The color shift correction is made when the right door is opened and closed, the transfer
2
Belt is removed and reinstalled, the IU is removed and reinstalled, the main power switch
is turned OFF and ON, or an image stabilization sequence is carried out from the control
panel.
Detection pattern for sub
scanning direction
Transfer belt
8. Write section (PH section)
Detection pattern for main
scanning direction
IDC/registration Sensor/1
and /2 (SE1, SE2)
4038T2C007AA
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