Theory of Operation 2-13
Transfer Roller Control
Detecting the Transfer Roller
The CTD (ADC) Sensor is used to detect the presence of the Transfer Roller. This 
determination is made whenever power is turned on, or a door is opened and closed. 
If the output of the CTD (ADC) Sensor is greater than the reference value the 
controller signals that the Transfer Roller is present. If the sensor output is lower than 
the reference, a Fatal Error indicates that the Transfer Roller is not installed.
If printing is stopped by a jam, a latent image remains on the Transfer Roller. To 
prevent a false error, the controller rotates the Transfer Roller a half turn. If the sensor 
output remains below the reference, a Transfer Roller missing error is generated. 
Otherwise, the sensor output indicates that the Transfer Roller is present and no 
additional error is reported.
Detecting Transfer Roller Life
The Transfer Roller consists of a bias transfer roller and a waste toner recovery space. 
Transfer Roller end of life occurs when the Toner Full Sensor detects that the waste 
toner recovery space is full.
1. Status of the waste toner reservoir is checked:
■ When the power is turned on.
■ When a door is opened and closed.
■ When paper exits the print engine.
2. Transfer Roller is at End of Life warning message is generated when the Toner 
Full Sensor detects the waste toner reservoir is full.
3. Replace Transfer Roller error message is generated if the print count and the 
toner dispense time are counted and the total count exceeds 15,000 prints.
4. Transfer Roller is at End of Life warning and Replace Transfer Roller error 
messages are reset if the Toner Full Sensor does not detect a full waste toner 
reservoir when power is turned on, or a door is opened and closed.