Canon iR4570 Series, Service Manual

Page: 246 / 876

Chapter 7
7-10
7.4 Image Stabilization Control
7.4.1 Overview
0006-5986
iR2270 / iR2870 / iR3570 / iR4570
At times, changes in the environment or wear on the machine can cause its image output to become unstable. To
make sure that its output will remain stable at all times, the machine uses the following control mechanisms:
T-7-7
F-7-12
7.4.2 APVC Control
0006-5987
iR2270 / iR2870 / iR3570 / iR4570
The term APVC stands for "auto primary voltage control," and it is a mechanism used to control the primary charging
application voltage (DC component) to suit the film thickness of the machine's photosensitive drum. APVC is
performed every 500 sheets while the machine is in operation. It is forcibly performed when the drum unit is
replaced.
[1] Drum film thickness detection
control corrects the development contrast.
[2] Developing contrast control determines the appropriate primary
charging DC bias and developing DC bias.
[3] ATVC control corrects the transfer bias.
BK
[2]
[1] [3]