Color Registration Control - Xerox Phaser 7500 Service Manual

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Table of Contents

Theory of Operation

Color Registration Control

Types of Color Registration Control

The Phaser 7500 is a Full Color Printer that uses the tandem system, where each

color - Yellow, Magenta, Cyan, and Black has its own Drum and Developer Housing

Assembly. Because each color forms an image on their own Drum, which are then

overlayed to create one image, color shift may occur due to Drum misalignments,

skewed installation positions, and etc. The function to correct this problem is the

Color Registration Control or Regi Con.

The Phaser 7500 provides the following types of control according to the

operation timings.

Closed Loop Regi Con

When the power is turned On or if the printer internal temperature has changed

since the last operation when the IOT is operating (when the Drums and belts are

rotating), a patch for the Color Registration Control is created on the belt for the

detection/correction of color shift.

The color shift is detected by the MOB Sensors (x2). A combination of rough

adjustments and fine adjustments are performed according to the conditions.

Open Loop Regi Con

The color shift for each color is calculated and corrected based on the changes in

the printer internal temperature at the heading of a page during the print job. This

correction is performed in both lateral direction (fast scan direction) and process

direction (slow scan direction).

LPH Controller

Phaser 7500 Printer Service Manual