HP P2050 manual Image-formation system, Primary charging

Image-formation system

Laser printing requires the interaction of several different technologies, including electronics, optics, and electrophotographics, to provide a printed page. Each process functions independently and must be coordinated with the other product processes. Image formation consists of the following five processes:

●electrostatic latent-image formation

●developing

●transfer

●fusing

●drum cleaning

The five processes contain seven steps.

Figure 5-8Image-formation system

Media path

Direction of the drum rotation	Latent image formation
Block	2. Laser-beam exposure
Step

1. Primary charging

Developing

3. Developing

Drum cleaning

7. Drum cleaning

Delivery

6. Fusing 5. Separation 4. Transfer Pickup

FusingTransfer

Step 1: Primary charging

DC and AC biases are applied to the primary charging roller, which transfers a uniform negative potential to the photosensitive drum.

Figure 5-9Primary charging

Primary charging roller

Primary charging bias

Photosensitive drum

90 Chapter 5 Theory of operation ENWW