Exposure Stage - Brother HL-1070 Service Manual

2.5.2
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
Drum
Sleeve
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Exposure Stage

Drum
Paper
Laser beam
f
lens
Lens
reduced forming the electrostatic image to be printed.
1 Cycle of drum
1 2
(a)
+1000
+700
(b)
+400
+300
Polygon mirror
Motor
Fig. 2.28
1
3 4
2
3
4
Time
Fig. 2.29
II-22
Laser Beam
Primary charging
Laser beam exposure and developing
(a) Unexposed area
( Non image area )
(b) Exposed area
( Image area )
Transfer the image to paper
Erase the residual potential