To permanently affix the toner, the paper passes through a fuser unit, which usually comprises two rolls coated with silicone rubber: the fuser roll and the pressure roll. Silicones are used in various degrees of hardness to ensure a sufficiently large contact area (nip) and a defined period of contact between the toner and the fuser unit.

One of the most important properties required of silicone elastomers used in the production of pressure rollers is low compression set. The reason is that the pressure roll is generally softer than the fuser roll and so is deformed more.

In the fusing process, the fuser roller transfers the thermal energy to the toner and to the paper. It is essential for the silicone elastomer to have high thermal conductivity.

The straightforward transport and processing of electrically charged toner particles on paper requires the presence of electrically conductive silicone rubber in several areas of the copier. WACKER provides several grades for this purpose.