Lexmark MS312 Service Manual page 276

Step 2: Expose
The laser fires a focused beam of light at the surface of the photoconductor and writes an invisible image, called a latent
image. The laser beam only discharges the surface where the beam hits the photoconductor. This creates a difference
in charge potential between the exposed area and the rest of the photoconductor surface.
DRUM
Step 3: Develop
Once the laser exposes the photoconductor, the HVPS sends charge to the developer roll. Because of the charge
difference between the toner on the developer roller and the electrostatic image created by the laser, the toner is
attracted to areas of the photoconductor surface exposed by the laser.
Modulated
Laser Beam
Printhead
Drum Surface
Image
Laser Beam
Invisible Latent Image
Appendix C: Theory of operation
276
Drum Surface
Voltage
Laser Beam
Discharge
Level
0V
4514