Exposure - Mita DP-2800 Service Manual

5A2

Exposure

The charged surface of the drum B is then scanned by the laser beam from the scanner
unit A.
A
B
The laser beam is switched on for a black dot and off for a white (blank) dot according to
the print data. Whenever it is illuminated by the laser beam, the electrical resistance of the
photoconductor is reduced, the potential on the photoconductor is also lowered from
approximately 250 V to 20 V, effectively driving the charge through the a-Si layer down to
the aluminum base.
LASER BEAM
LASER BEAM
+ + + + + + + + +
250 V
a-Si LAYER
20 V
+ + + +
– – – –
0 V
ALUMINUM
4-5