Dell 2130cn Service Manual page 771

Chapter 6 Principles of Operation
- The laser beam is irradiated according to the printing data (image data) output from the printer
controller. The laser beam is output only when printing data is pixels (micro points composing
characters or pictures). (The laser diode lights up for parts to be developed by toner, and not for
parts that are not to be developed.)
The drum surface irradiated by the laser beam becomes a conductor, and the negative charge on
the drum surface flows to the positive side and the charges cancel each other out so that the
potential on the drum surface drops. The part on the surface where potential drops becomes the
electrostatic latent image.
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