In this step, the surface of the photosensitive drum is charged to an even negative potential to prepare for the formation of an image. The machine uses a roller

charging method, in which charges are directly applied to the surface of the photosensitive drum.

The machine's primary charging roller is made from conducting rubber, and is given both AC and DC biases to keep the surface potential of the photosensitive drum

even.

Step 2: laser beam exposure

In this step, a static image is formed on the surface of the photosensitive drum.

The negatively charged surface of the photosensitive drum is exposed by a laser beam. As a result, those areas hit by the beam are neutralized (light area), thus

eliminating negative charges and consequently forming a static image on the surface.

Primary charging roller

F-7-4

Laser beam

Dark area

Light area

F-7-5

Photosensitive drum

AC bias

DC bias

Chapter 7

7-5