Powder transport, fusing and imaging apparatus

Abstract

A transport member moves in a cyclic path to carry material from a first location to a second location at a different temperature, and a thermal shunt connects portions of the transport member. Counter-moving portions of the member are positioned to exchange heat with each other along an intermediate portion of the path, so that minimum energy is lost to the environment. In one embodiment as a printing apparatus, a belt transports a heat-fusible toner to a heater location where it is transferred and fused, i.e., transfused, as a print image to a sheet. Effective powder pick up and release is obtained in the printing apparatus with a transport member having an elastomeric layer of a softness which conforms to a receiving member of characteristic surface roughness, and a non-tacky outer coating which is harder than the elastomeric layer. The outer coating is thin enough to conform to the surface roughness, but hard enough to prevent entrainment of toner particles. A powdered filler allows a single thin belt to serve as the imaging element, i.e., as the latent and developed image carrier, as well as the element which transfers and fuses toner to a print. A duplex system employs two belt-imaging members which each travel over one of a pair of opposed pressure rollers having identical elastic characteristics.