Brother HL-4000CN Service Manual page 107

5.4 Front ASSY In
5.4.1 Major functions
Holder ASSY CTD
Reads the density of the toner image prepared on the surface of transfer roll cartridge
in the transfer roll cartridge unit ASSY (refer to "5.7 Transfer Roll Cartridge ASSY &
Fuser") and feeds it back to the process control (refer to "7.4 Process Control").
Sensor TNR full
Detects that the toner collect space in the transfer roll cartridge unit ASSY (refer to "5.7
Transfer Roll Cartridge ASSY & Fuser") has become full of waste toner to be collected.
Fuser drive ASSY
Supplies the drive to the fuser ASSY (refer to "5.7 Transfer Roll Cartridge ASSY &
Fuser").
5.4.2 Reference diagram
HOLDER ASSY CTD
III-29
FUSER ASSY
SENSOR TNR FULL
FUSER DRIVE ASSY
Fig.3-37