Recently in the printing production market, there is high demand for printers to support various paper types having wide-ranging basis weight, while at the same time realizing high productivity. The fusing device heats and melts toner electrostatically adhered to paper, and then applies pressure on the toner to fix it on paper. However, fusing failure occurs more readily on paper having a high basis weight, that is, the image on paper is lost. As such paper has a large heat capacity, adequate heat is not applied to the toner, which consequently does not melt sufficiently.
Belt-roll fusing technology uses two heat rolls-one laid out on the inner side and one along the outer side of the fusing belt. By creating a sufficient contact area between the fusing belt and heat rolls, the fusing belt will be heated evenly and sufficiently, thereby enabling a stable supply of heat for melting toner. This technology is also capable of successfully fusing toner onto thick paper and thus achieving high image quality, even when the machine is running at a high speed.
As shown in Fig. 1, the nip where the fusing belt firmly contacts paper is extended. This contact is realized by the pad being laid out on the backside of the belt, along with the conventional roll nip (Fig. 1-a), being ensured. By extending the nip (Fig. 1-b), the fusing belt contacts the toner for a longer time, and allows the fusing belt's heat to be used effectively for melting toner.
Fig. 1: Enlarged diagram of where the fusing belt firmly contacts paper