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

detection