Brother HL-4000CN, Service Manual, Page: 126 / 345

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7.6 Transfer Roll Cartridge Unit ASSY Control
7.6.1 Detecting the installation of transfer roll cartridge unit ASSY
Whether the transfer roll cartridge unit ASSY is installed is detected when the power is
turned on, or the front cover is opened and closed. The sensor for detecting the
installation is not provided, but judgment is made from the output of the holder ASSY
CTD.
The light is emitted from the LED of holder ASSY CTD with the specified light quantity,
and if the output of the holder ASSY CTD is larger than the specified value, the controller
judges as installation. If the operation stops by a jam, the toner image could be put on
the transfer roll cartridge and in such a case, the sensor output is reduced, causing the
controller to judge as uninstallation. To prevent this wrong detection, the transfer roll
cartridge is rotated by a half turn if the output is less than the specified value. Then,
when the output of the holder ASSY CTD is larger than the specified value, the controller
judges as installation, or if less than the specified value, the controller judges as
uninstallation.
7.6.2 Detecting the life of transfer roll cartridge unit ASSY
The transfer roll cartridge unit ASSY consists of a transfer roll cartridge and a waste toner
recovery system. The life of the transfer roll cartridge unit ASSY is detected when the
toner recovery space has become full.
The full toner recovery space is detected by the sensor TNR full.
1) Check timing of full waste toner recovery space
•
When the power is turned on, or the front cover is opened and closed
•
When paper is outputted
2) Output of " Transfer Roll Cartridge Life Warning"
The " Transfer Roll Cartridge Life Warning" is outputted when the sensor TNR full
detects the full toner recovery space.
3) Output of " Transfer Roll Cartridge Life Error"
After the output of " Transfer Roll Cartridge Life Warning", the print count and the
toner dispense time are counted up, and if total counts exceed the specified value,
the " Transfer Roll Cartridge Life Error" is outputted.
4) Reset of " Transfer Roll Cartridge Life Warning"/" Transfer Roll Cartridge Life Error"
The " Transfer Roll Cartridge Life Warning" and " Transfer Roll Cartridge Life Error"
are reset, if the sensor TNR full does not detect the full toner recovery space when
the power is turned on, or the front cover is opened and closed.