Xerox Phaser 6200B, Service Manual

Page: 329 / 386

Theory of Operation 311
Transfer Roller Assembly Control
Detecting the Installation of the Transfer Roller Assembly
The CTD Sensor detects the installation of the Transfer Roller when power to the
printer is turned on, or the front cover is opened and closed.
Light emits from the LED of the CTD sensor with the specified intensity and if the
output of the CTD Sensor is greater than the specified value the controller signals
installation of the Transfer Roller.
If printing is stopped by a jam, the toner image will be placed on the Transfer Roller.
The this case the sensor output result is low, causing the controller to report the
transfer roller as missing. To prevent this, the Transfer Roller is rotated a half turn if
output is lower than the specified value. If the output of the CTD sensor is greater
than the specified value, then the controller senses installation. If the output is less
than the specified value, the controller senses the transfer roller is not installed.
Detecting the Life of the Transfer Roller Assembly
The Transfer Roller Assembly consists of a bias transfer roller and a waste toner
recovery system. End of life of the Transfer Roller is detected when the toner
recovery space becomes full.
The full toner recovery space is detected by the Toner Full Sensor.
1. Timing check for a full waste toner recovery space is:
■
When the power is turned on.
■
When the front cover is opened and closed.
■
When paper exits the print engine.
2. “Transfer Roller is at End of Life” error message is received when the toner full
sensor detects the toner recovery space is full.
3. “Replace Transfer Roller ” warning message is received if the print count and the
toner dispense time are counted and the total count exceeds 15,000 prints.