HP LASERJET ENTERPRISE M855 - Page 71

Step 1: Pre-exposure
Light from the pre-exposure LED strikes the surface of the photosensitive drum to remove any
residual electrical charges from the drum surface.
Figure 1-11 Pre-exposure
Photosensitive drum
LED
Step 2: Primary charging
The primary-charging roller contacts the photosensitive drum and charges the drum with negative
potential.
Figure 1-12 Primary charging
DC bias
Photosensitive drum
Primary charging roller
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