HEAT-TRANSFER AND TONER MELTING IN AN ELECTROPHOTOGRAPHIC FUSER SYSTEM

An optimizing method for temperature and pressure in a heatroll comprising a fluoride surface layer and an aluminum core is examined. A thinner surface layer obviously makes the fusion more effective. This mechanism was numerically analyzed in detail for thermal conduction. A sharp rise in heat flux to the toner is observed within a certain thickness of the surface layer. The sharp rise is caused by a significant heat flux from the aluminum core to the surface layer during the nip period. Shear rate in the toner particle induced by nip pressure was analyzed theoretically. Shear rate has a peak in the nip period. The peak becomes higher and appears later for higher pressure. The toner temperature increases as the nip time passes. The lowest toner melt viscosity can be obtained when both shear rate and temperature are high. Therefore, the shear rate peak should be set late to achieve a good fit between temperatures and shear rate.