HP Pro 4300 C9H70UT C9H70UT#ABA manual Electrostatic latent-image formation, Primary charging

Electrostatic latent-image formation

Forming the electrostatic latent image on the photosensitive drum requires applying a uniform negative charge (bias) to the surface of the drum and then the exposing it to the laser beam. The laser beam naturalizes the section of the drum so that it attracts toner during the developing operation.

Primary charging

The conditioning process consists the primary charging roller applying a uniform negative charge on the surface of the drum. The primary charging roller is coated with conductive rubber that has an ac bias applied. This erases any residual charges and maintains a constant drum surface charge. The print density setting modifies the amount of dc voltage.

Primary charging roller

ac bias

Photosensitive drum

dc bias

Figure 51. Primary charging of the photosensitive drum

120 Theory of operation Q2431-90912