Brother HL-3040CN Service Manual page 34

THEORY OF OPERATION
This chapter gives an overview of the 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.
1. GENERAL BLOCK DIAGRAM ..................................................................2-1
2. ELECTRONICS GENERAL BLOCK DIAGRAM........................................2-2
3. MECHANICS ..............................................................................................2-3
3.1 Cross-section Drawing ............................................................................................... 2-3
3.2 Paper Feeding ............................................................................................................ 2-4
3.2.1 Plate-up function of the paper tray .................................................................... 2-5
3.2.2 Paper supply...................................................................................................... 2-6
3.2.3 Paper registration .............................................................................................. 2-7
3.2.4 Paper eject ........................................................................................................ 2-8
3.2.5 Paper supply from manual feed slot and paper eject from back........................ 2-9
3.3 Toner Cartridge ......................................................................................................... 2-10
3.3.1 Type of toner cartridge..................................................................................... 2-10
3.3.2 Life of toner cartridge....................................................................................... 2-10
3.3.3 Method of detecting toner life .......................................................................... 2-11
3.3.4 Relationship between toner amount and life of toner cartridge in number of
rotations of develop roller ................................................................................ 2-11
3.3.5 New toner detection......................................................................................... 2-13
3.3.6 Method of counting the number of toner replacements ................................... 2-15
3.4 Principle of Color Overlapping .................................................................................. 2-16
3.5 Basic Printing Principle ............................................................................................. 2-17
3.5.1 Charging .......................................................................................................... 2-18
3.5.2 Exposure ......................................................................................................... 2-19
3.5.3 Development ................................................................................................... 2-20
3.5.4 Transfer ........................................................................................................... 2-21
3.5.5 Fusing.............................................................................................................. 2-22
3.5.6 Toner cleaning ................................................................................................. 2-23
3.6 Location of Sensors .................................................................................................. 2-24
3.7 Adjustment of Color Registration .............................................................................. 2-28
3.7.1 Color registration error in sub/main scanning direction ................................... 2-28
3.8 Adjustment of Color Density ..................................................................................... 2-28
CHAPTER 2
CONTENTS
Confidential