2-30 Phaser 6180 Color Laser Printer Service Manual
Theory of Operation
Transfer Unit
The Transfer Unit consists of the Belt, ADC Sensor, ADC Solenoid, ADC Pad, 
and ESA Roller.
■ Belt
The Belt feeds the paper toward the direction of the Fuser.
■ ADC Sensor
The ADC Sensor detects the toner patches on the Belt and converts them 
to voltage value. The voltage value is used to control the density of toner.
■ ADC Solenoid
To activate the ADC Pad, turn On the ADC Solenoid for a fixed time 
before the ADC Sensor starts reading the toner patches. When turned 
On, the ADC Solenoid activates the ADC Pad, which cleans 
contamination on the ADC Sensor surface.
■ ESA Roller
The ESA Roller discharges a positive voltage to the paper. Toner transfer 
efficiency is raised by applying a positive charge to the paper.
s6180-273
Normal Position
Spring
ADC Solenoid
ADC Solenoid On
Position of ADC Sensor 
(Window = Open)
ADC Pad
ADC Pad
Shutter
Position of ADC Sensor
ADC Sensor