Brother HL-1040, HL-820, HL-1020 manual Exposure Stage

2.5.2Exposure Stage

After the drum is positively charged, it is exposed to the light emitted from the laser unit.

	Laser Beam
	Drum
	Paper
	Laser beam
	f ￿lens
Laser detector	Polygon mirror

Laser diode

Motor

Lens

Fig. 2-38

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.

(V)
Potential	+1150
Surface	+700

+400 Drum +300 Sleeve

	1 Cycle of drum			1
1	2	3	4	2

(a)
	3
(b)	4

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

Time

Fig. 2-39

II-31