Exposure Stage - Brother mfc8440 Service Manual
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Also See for mfc8440:
- User manual (426 pages) ,
- Software user's manual (183 pages) ,
- Quick setup manual (52 pages)
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2.7.2
Exposure stage
After the drum is positively charged, it is exposed to the light emitted from the laser unit.
Laser detector
Laser diode
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.
Surface
potential (V)
+870
+400
+150
Drum
sleeve
0
Drum
Paper
Laser beam
f θ lens
Lens
1 Cycle of drum
1
2
3
(a)
(b)
Time
MFC-8440/8840D/8840DN, DCP-8040/8045D/8045DN
Polygon mirror
Motor
Fig. 3-36
Primary charging
1
2
Laser beam exposure and developing
(a) Unexposed area
(Non image area)
(b) Exposed area
(Image area)
Transfer the image to paper
3
Fig. 3-37
3-23
SERVICE MANUAL
Laser beam
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