Brother HL-1260 service manual Primary charge, Scanning exposure, + + +

Step 1 Primary charge

Primary charging roller

AC bias

Photosensitive drum

DC bias

Figure 2.9

As preparation for latent image formation, a uniform negative potential is applied to the photosensitive drum surface. The printer uses the charging method that directly charges the drum for the primary charge.

The primary charging roller consists of conductive rubber. In addition to DC bias, AC bias is applied to the primary charging roller to keep the potential on the drum surface uniform. This DC bias is changed with the developing DC bias.

This charging method has advantages such as lower applied voltage, less ozone generation, etc., compared with the corona charge system.

Step 2 Scanning exposure

Laser beam

_ _ _

+ + +

Unexposed area

Exposed area

Figure 2.10

When the laser beam scans the drum surface, it causes the charge to be neutralized in the areas struck by the beam. Areas on the drum with no charge form the electrostatic latent image.

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