Atvc (Auto Transfer Voltage Control) - Develop QC 2235 Plus Service Manual

QC 2235plus Theory of Operation Ver.1.0 Mar. 2004
10.3.5

ATVC (Auto Transfer Voltage Control)

• To optimize image transfer output, the machine is provided with ATVC control, or Auto
Transfer Voltage Control. The control lets a constant current flow through each of the
Image Transfer Rollers. Then, from the voltage detected, the resistances of the 1st
Image Transfer Roller, 2nd Image Transfer Roller, and Transfer Belt are measured. The
optimum image transfer output voltages applied to the 1st and 2nd Image Transfer Roll-
ers during printing are thereby automatically adjusted.
A. Overview of ATVC operation
Constant current is output to the 1st or
2nd Image Transfer Roller.
The resistance of the 1st or 2nd Image
Transfer Roller is measured.
The voltage to be applied the 1st or 2nd
Image Transfer Roller is determined.
2nd Image Transfer Current Feedback Terminal
B. 1st image transfer ATVC operation
1. The 1st image transfer constant current for each color of toner output from the DC
power Supply/1 is fed back to the DC power Supply/1 via the 1st Image Transfer Roller,
Transfer Belt, and PC Drum ground. This allows the resistance of the Transfer Belt to be
measured.
2. The measured resistance is used as the basis for determining the optimum 1st image
transfer voltage for each color of toner.
C. 2nd image transfer ATVC operation
1. The 2nd image transfer constant current output from the DC power Supply/1 is fed back
to the DC power Supply/1 via the 2nd Image Transfer Roller, Transfer Belt, and Transfer
Belt Drive Roller. This allows the resistance of the Transfer Belt to be measured.
2. The measured resistance, together with the type of paper, temperature and humidity,
and the color or monochrome mode, is used as the basis for determining the optimum
2nd image transfer voltage.
D. 1st and 2nd image transfer ATVC operation timing
• The 1st and 2nd image transfer ATVC operations are carried out immediately before the
execution of image stabilization control.
• The control operation is not, however, performed in Image Stabilizer Mode 3.
Constant Voltage
Constant
Measured
Resistance
Current
Value
2nd Image Transfer Roller
Transfer Belt
Transfer Belt Drive Roller
4036ma2520c0
2-41
Transfer Corona section
HV1
Constant
Current
1st Image Transfer Roller
Transfer Belt
PC Drum Ground