Brother MFC8440D Service Manual page 6

7/13/2019
TABLE OF CONTENTS
2.4.9 Rear cover sensor ............................................................................................................. 3-21
2.4.10 HP sensor ......................................................................................................................... 3-21
2.5 Drum Unit .......................................................................................................................3-22
2.5.1 Photosensitive drum.......................................................................................................... 3-22
2.5.2 Primary charger................................................................................................................. 3-22
2.5.3 Transfer roller .................................................................................................................... 3-22
2.5.4 Cleaner..............................................................................................................................3-22
2.6 Toner Cartridge ..............................................................................................................3-22
2.7 Print Process ..................................................................................................................3-22
2.7.1 Charging............................................................................................................................3-22
2.7.2 Exposure stage ................................................................................................................. 3-23
2.7.3 Developing ........................................................................................................................ 3-24
2.7.4 Transfer.............................................................................................................................3-24
2.7.5 Fixing stage ....................................................................................................................... 3-25
CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY .............................. 4-1
1. SAFETY PRECAUTIONS ....................................................................................... 4-1
2. DISASSEMBLY FLOW ........................................................................................... 4-2
3. DISASSEMBLY PROCEDURE ............................................................................... 4-3
3.1 AC Cord............................................................................................................................4-3
3.2 Drum Unit .........................................................................................................................4-3
3.3 Paper Tray........................................................................................................................4-4
3.4 DX Feed ASSY (MFC-8840D/8840DN, DCP-8045D/8045DN only) ..............................4-14
3.5 Access Cover / Battery ................................................................................................... 4-17
3.6 Driver PCB Access Cover .............................................................................................. 4-18
3.7 ADF Unit .........................................................................................................................4-19
3.8 Document Scanner.........................................................................................................4-28
3.9 Panel Unit .......................................................................................................................4-33
3.10 Rear Cover C (MFC-8440, DCP-8040 only)................................................................... 4-36
3.11 Outer Chute (MFC-8440, DCP-8040 only) ..................................................................... 4-37
3.12 Rear Cover MP ASSY / Outer Chute MP ASSY
(MFC-8840D/8840DN, DCP-8045D/8045DN only) ........................................................4-38
3.13 Rear Cover L/R............................................................................................................... 4-39
3.14 Side Cover L/R ...............................................................................................................4-40
3.15 Joint Cover .....................................................................................................................4-41
3.16 Front Cover ASSY (MFC-8440, DCP-8040 only) ........................................................... 4-45
3.17 MP Unit (MFC-8840D/8840DN, DCP-8045D/8045DN only) ..........................................4-46
3.18 Rear Cover Sensor.........................................................................................................4-51
3.19 NCU (MFC-8440/8840D/8840DN only) ..........................................................................4-52
3.20 Fixing Unit.......................................................................................................................4-53
3.21 Laser Unit .......................................................................................................................4-62
3.22 Main PCB .......................................................................................................................4-64
3.23 Base Plate / LV Insulation Sheet ....................................................................................4-66
3.24 DX-Sensor PCB ASSY (MFC-8840D/8840DN, DCP-8045D/8045DN only)...................4-67
3.25 Engine PCB ....................................................................................................................4-68
3.26 High-voltage PS PCB ASSY...........................................................................................4-69
3.27 Low-voltage PS PCB ASSY............................................................................................ 4-70
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