MFC-8440/8840D/8840DN, DCP-8040/8045D/8045DN
SERVICE MANUAL
3-23
2.7.2 Exposure
stage
After the drum is positively charged, it is exposed to the light emitted from the laser unit.
Fig. 3-36
The area exposed to the laser beam is the image to be printed. The surface potential of the
exposed area is reduced, forming the electrostatic image to be printed.
Fig. 3-37
Drum
Lens
Laser beam
Polygon mirror
Paper
Laser detector
Laser diode
Motor
Laser beam
f
θ
lens
3
Primary charging
Laser beam exposure and developing
(a) Unexposed area
(Non image area)
(b) Exposed area
(Image area)
Transfer the image to paper
Time
Drum
sleeve
0
2
1
1
2
3
(a)
(b)
+150
+400
+870
Surface
potential (V)
1 Cycle of drum
Summary of Contents for DCP 8040 - B/W Laser - All-in-One
Page 272: ...CHAPTER 7 MAINTENANCE MODE 7 6 Fig 7 3 l m a b c d e f g h i j k ...
Page 343: ...APPENDIX 4 CIRCUIT DIAGRAMS A 50 Appendix 4 1 Main PCB Circuit Diagram 1 7 ...
Page 345: ...APPENDIX 4 CIRCUIT DIAGRAMS A 52 Appendix 4 3 Main PCB Circuit Diagram 3 7 ...
Page 347: ...APPENDIX 4 CIRCUIT DIAGRAMS A 54 Appendix 4 5 Main PCB Circuit Diagram 5 7 ...
Page 349: ...APPENDIX 4 CIRCUIT DIAGRAMS A 56 Appendix 4 7 Main PCB Circuit Diagram 7 7 ...
Page 351: ...APPENDIX 4 CIRCUIT DIAGRAMS A 58 Appendix 4 9 Engine PCB Circuit Diagram 1 2 ...
Page 353: ...APPENDIX 4 CIRCUIT DIAGRAMS A 60 Appendix 4 11 NCU PCB Circuit Diagram U S A ...
Page 355: ...APPENDIX 4 CIRCUIT DIAGRAMS A 62 Appendix 4 13 NCU PCB Circuit Diagram Asia ...
Page 357: ...APPENDIX 4 CIRCUIT DIAGRAMS A 64 Appendix 4 15 Control Panel PCB Circuit Diagram ...
Page 362: ...April 04 SM FAX027 1 8C5903 Printed in Japan ...
