Oki OKIFAX 5950 Series Maintenance Manual page 499

The EP (image) drum surface is charged to about -800 V by the contact charge of the
charge roller.
When light from the LED head irradiates the EP (image) drum surface, the light energy
generates positive and negative carriers in the CGL. The positive carriers are moved to
the CTL by an electrical field acting on the EP (image) drum. Likewise, the negative
carriers flow into the aluminum layer (ground).
The positive carriers moved to the CTL combine with the negative charges on the EP
(image) drum surface accumulated by the contact charge of the charge roller, lowering
the potential on the EP (image) drum surface. The resultant drop in the potential of the
irradiated part of the EP (image) drum surface forms an electrostatic latent image on it.
The irradiated part of the EP (image) drum surface is kept at about -100 V.
EP drum
surface potential
OF5750/5950 Series January 2001
Light
(V)
from
LED
—800
—100
0
Charged part
Part
irradiated
by
LED
B - 7
PRINT OPERATIONS
Charged
part
DESCRIPTION OF