Color Registration Detection - Xerox 7300B - Phaser Color Laser Printer Service Manual

Color Registration Detection

Reflection-type optical sensors, for detecting color registration, are mounted under
the transfer unit, one on the right and one on the left in front of the cleaning blade. A
solenoid-activated shutter opens up so the sensors can "see" the transfer unit. On the
right and left edges of the belt, an alignment pattern (a series of primary color toner
patches) is printed, which the reflection-type optical sensors read to measure the
amount of misalignment base on the position of the black toner patch. According to
this measurement, the printer determines the correct value and automatically adjusts
color registration in the main scanning, sub-scanning and diagonal directions. This
operation is implemented when the printer is turned on and when 400 sheets have
been printed.
Imaging Unit
Transfer
Unit
Color Registration Sensor
(Figure seen from below)
Theory of Operation
C M
C M
Belt running direction
Transfer
Unit
Color Registration
Sensor
Belt running direction
Color Registration
Ssensor
LED Head
Y K
Y K
Cleaning
blade
Cleaning blade
S7300-145
8-241