Theory of Operation 2-11Transfer Roller Assembly ControlDetecting the Installation of the Transfer Roller AssemblyAlthough there is no seperate sensor for this, the output of the CTD Sensor is used todetect installation or absence of the Transfer Roller when power to the printer isturned on, or the front cover is opened and closed.Light emits from the LED of the CTD sensor with the specified intensity and if theoutput of the CTD Sensor is greater than the specified value the controller signals thatthe Transfer Roller is present (installed).If printing is stopped by a jam, the toner image will be placed on the Transfer Roller.In this case the sensor output result is low, causing the controller to report the TransferRoller as missing. To prevent this, the Transfer Roller is rotated a half turn if output islower than the specified value. If the output of the CTD sensor is than greater than thespecified value, the controller reports installation of the Transfer Roller. If the outputremains less than the specified value, the controller reports that the Transfer Roller isnot installed.Detecting the Life of the Transfer Roller AssemblyThe Transfer Roller Assembly consists of a bias transfer roller and a waste tonerrecovery space. End of life of the Transfer Roller is detected when the waste tonerrecovery space becomes full.The full waste toner recovery space is detected by the Toner Full Sensor.1. Status of the waste toner recovery space is checked:■ 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 generated when the toner fullsensor detects the waste toner recovery space is full.3. “Replace Transfer Roller ” warning message is generated if the print count andthe toner dispense time are counted and the total count exceeds 15,000 prints.4. “Transfer Roller is at End of Life” error/ “Replace Transfer Roller ” warningmessages are reset if the toner full sensor does not detect a full waste tonerrecovery space when power is turned on, or the front cover is opened and closed.
