Automatic Bias Control - Canon imageRUNNERC1022 Service Manual

Chapter 8

8.4.2 Automatic Bias Control

0019-8977
imageRUNNER C1022 / imageRUNNER C1022i / Color imageRUNNER C1030 / Color imageRUNNER C1030iF
Depending on the individual difference or deterioration condition of the transfer roller, attraction roller, and ETB, differences and changes occur in the resistance
value of each unit. In this condition, a transfer failure may occur when an expected level of bias is not applied to each roller.
This control is executed to apply the optimum level of bias to each roller based on the measured voltage of each roller.
The DC controller sends a constant current to the transfer roller (Bk) and attraction roller when starting print operation and measures the voltage at that point. Based
on the measured voltage, it extracts the optimum transfer and attraction biases.
In the subsequent print operation, the optimum transfer and attraction biases are applied to stabilize the image quality.
ETB
Current
Transfer roller (Bk)
ETB engaged roller
ETB
Current
Attraction roller
Constant current V Voltage
V Voltage
detection
Constant current
detection
Photosensitive drum (Bk)
b. Attraction roller voltage detection
a. Transfer roller voltage detection
F-8-25
8-19