Page 185 - Graphic Design and Print Production Fundamentals

Graphic Design 173

Figure 6.9 Cleaning

Erasing

In this stage, an LED array exposes the length of the drum, bringing this area of the drum to near zero
volts. This prepares the drum surface for the charging stage of the next print cycle.

Fusing

This is the final stage in the electophotographic process. The fusing mechanism, or fuser, consists of a
heat roller, a pressure roller, and cleaning mechanism (see Figure 6.10). Toner is composed mostly of
resin. When the toner is heated by the heat roller and pressure applied by the complement pressure roller,
it melts and is pressed into the fibres of the sheet. The toner is never absorbed by the paper or substrate
but rather is bonded to the surface. A negative charge is applied to the heat roller or belt to prevent the
toner from being attracted to it and the cleaning section removes any toner or other contaminates that
may have remained on the heat roller. Heat may also be applied to the pressure roller (at a much lower
temperature) to prevent the sheet from curling.