Color Shift Correction System - Develop QC 2235 Plus Service Manual

QC 2235plus Theory of Operation Ver.1.0 Mar. 2004
4.2.2

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 LED assemblies being out of correct
position. 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
sub scanning direction is produced at the front and rear on the Transfer Belt. Each of
AIDC/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 main scanning direction is next produced at the
front and rear on the Transfer Belt. Each of AIDC/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 repre-
senting 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 LED is turned
ON).
• The color shift correction is made when the Left Door is opened and closed, the IU is
removed and reinstalled, or an image stabilization sequence is carried out from the con-
trol panel.
Detection Pattern for Sub
Scanning Direction
Transfer Belt
AIDC/Registration Sensor/1
and /2 (PC8 and PC9)
2-11
Write section (PH section)
Detection Pattern for Main
Scanning Direction
4036ma2227c0
4036ma2226c0