TABLEOF CONTENTS
iv
2.2.3 Paper eject .................................................................................................................. 3-24
2.3 Sensors.....................................................................................................................3-24
2.3.1 Coversensors A and B ................................................................................................ 3-24
2.3.2 Toner sensor ............................................................................................................... 3-25
2.4 DrumUnit...................................................................................................................3-25
2.4.1 Photosensitivedrum .................................................................................................... 3-25
2.4.2 Primarycharger ........................................................................................................... 3-25
2.4.3 Transferroller ..............................................................................................................3-25
2.4.5 Cleaner........................................................................................................................3-25
2.5 Toner Cartridge..........................................................................................................3-25
2.6 PrintProcess .............................................................................................................3-26
2.6.1 Charging......................................................................................................................3-26
2.6.2 Exposurestage............................................................................................................ 3-26
2.6.3 Developing...................................................................................................................3-27
2.6.4 Transfer.......................................................................................................................3-28
2.6.5 Fixingstage .................................................................................................................3-28
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 ACCord .......................................................................................................................4-3
3.2 DrumUnit.....................................................................................................................4-3
3.3 Paper Cassette ............................................................................................................4-4
3.4 Network Board (for HL-1270N only)............................................................................4-10
3.5 FrontCover................................................................................................................ 4-11
3.6 TopCover ..................................................................................................................4-12
3.7 MainCover ................................................................................................................4-13
3.8 LaserUnit ..................................................................................................................4-15
3.9 DriveUnit ...................................................................................................................4-16
3.10 Fixing Unit..................................................................................................................4-18
3.11 Base Plate ................................................................................................................. 4-27
3.12 Main PCB ASSY ........................................................................................................ 4-29
3.13 LowerTray Relay PCB ASSY (for HL-1250/1270N only) ............................................4-29
3.14 Low-voltagePower Supply PCB ASSY....................................................................... 4-30
3.15 EnginePCB ASSY / High-voltage Power Supply PCB ASSY...................................... 4-31
3.16 PanelPCB ASSY .......................................................................................................4-33
3.17 SolenoidASSY ..........................................................................................................4-33
3.18 Fan Motor ASSY ........................................................................................................4-36
3.19 TonerSensor PCB ASSY (Light Emission) .................................................................4-37
3.20 TonerSensor PCB ASSY (Light Reception) ...............................................................4-37
3.21 PaperPick-up Roller ASSY ........................................................................................4-38
3.22 PaperFeed Roller ASSY............................................................................................ 4-39
3.23 Outer Chute 1 ......................................................................................................... 4-39A

4. PACKING.............................................................................................................. 4-40