Lexmark 7462 series, Service Manual, Page: 669 / 729

This discharge/no discharge process creates an invisible, electrostatic image on the surface of the drum. This
image is called a latent image.
Modulated
Laser Beam
0V
DRUM
Drum Surface
Image Drum Surface
Voltage
Laser Beam
Discharge
Level
Invisible Latent Image
Laser Beam
Printhead
Development
The toner contained within the PC cartridge has an electrical property that causes it to adhere to the
development roll. The metering blade spreads the toner into a very thin layer on the development roll. Friction
between the development roll and the CM blade development roll generates a small electrical charge that is
transferred to the toner.
The surface of the developer roll is made up of a thin sheet of conductive material. The HVPS supplies the
development roll with two voltages: a DC voltage and an AC voltage. The DC voltage is used to transfer toner
from the development roll to the surface of the drum. The AC voltage agitates the toner on the development
roll, making toner transfer easier.
The development roll maintains a negative DC electrical potential. Negative charged areas of the drum have
a lower electrical potential, or higher relative negative value than the development roll. Discharged areas of
the drum have a higher electrical potential, or lower relative negative value, than the development roll. A
discharged point on the surface of the drum now appears less negative in relation to the negative charge on
the development roll.
7462
Appendix C: Theory of operation
669