HP LaserJet Pro P1102 HP LaserJet Professional P1100 Series Printer - Service - Page 42

Latent-image formation stage, Primary charging, Laser beam exposure, Step 1

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Latent-image formation stage During the latent-image formation stage, the laser/scanner forms an invisible image on the photosensitive drum in the print cartridge. Primary charging Step 1: dc and ac biases are applied to the primary charging roller, which transfers a uniform negative potential to the photosensitive drum. Figure 1-16 Primary charging Primary charging roller Photosensitive drum DC bias Laser beam exposure Step 2: The laser beam scans the photosensitive drum to neutralize negative charges on parts of the drum surface. An electrostatic latent image is formed on the drum where negative charges were neutralized. Figure 1-17 Laser beam exposure Laser beam Unexposed area Exposed area 24 Chapter 1 Theory of operation ENWW

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Latent-image formation stage
During the latent-image formation stage, the laser/scanner forms an invisible image on the
photosensitive drum in the print cartridge.
Primary charging
Step 1
: dc and ac biases are applied to the primary charging roller, which transfers a uniform negative
potential to the photosensitive drum.
Figure 1-16
Primary charging
DC bias
Photosensitive drum
Primary charging roller
Laser beam exposure
Step 2
: The laser beam scans the photosensitive drum to neutralize negative charges on parts of the
drum surface. An electrostatic latent image is formed on the drum where negative charges were
neutralized.
Figure 1-17
Laser beam exposure
Laser beam
Unexposed area
Exposed area
24
Chapter 1
Theory of operation
ENWW