Brother MFC-8460N Service Manual page 64

CHAPTER 3 THEORY OF OPERATION
This chapter gives an overview of the scanning and printing mechanisms as well as the sensors,
actuators, and control electronics. It aids in understanding the basic principles of operation as
well as locating defects for troubleshooting.
3.1 OVERVIEW ......................................................................................................................3-1
3.2 MECHANICAL COMPONENTS.......................................................................................3-2
3.2.1 Scanner Mechanism ............................................................................................3-3
3.2.2 Overview of Gear .................................................................................................3-9
3.2.3 Paper Transfer ...................................................................................................3-10
3.2.3.1 Paper supply ..............................................................................................3-10
3.2.3.2 Paper registration.......................................................................................3-12
3.2.3.3 Drum unit....................................................................................................3-12
3.2.3.4 Developing .................................................................................................3-13
3.2.3.5 Fixing stage................................................................................................3-14
3.2.3.6 Paper eject .................................................................................................3-15
3.2.3.7 Duplex printing (For the models with the DX only).....................................3-16
3.2.3.8 Paper feeding from the MP tray .................................................................3-17
3.2.3.9 LT tray ........................................................................................................3-17
3.2.4 Toner Cartridge ..................................................................................................3-18
3.2.4.1 Toner life end mode ...................................................................................3-18
3.2.4.2 New toner detection mechanism................................................................3-20
3.2.4.3 Counter reset during indication of "Toner Life End" ...................................3-21
3.2.5 Print Process ......................................................................................................3-22
3.2.5.1 Charging.....................................................................................................3-22
3.2.5.2 Exposure stage ..........................................................................................3-22
3.2.5.3 Transfer......................................................................................................3-23
3.2.6 Sensors ..............................................................................................................3-24
3.3 CONTROL ELECTRONICS...........................................................................................3-25
3.3.1 Components .......................................................................................................3-25
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