Oki B 4100 Maintenance Manual page 527

3) Exposure
Light emitted from the LED head irradiates the EP (image) drum surface with negative charges.
The surface potential of the irradiated part of the EP drum drops, thereby forming an electrostatic
latent image associated with the image signal.
PWU
EP drum
The EP (image) drum is coated with an underlayer (UL), a carrier generation layer (CGL), and
carrier transfer layer (CTL) on the aluminum base. The organic photo conductor layer (OPC),
comprising a CTL and a CGL, is about 20 m thick.
40055101TH Rev.4
Charge roller
LED head
Paper
20 m
30 mm
LED head
EP drum
EP drum
CTL
CGL
UL
Base
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