Abstract Modern digital copy machines are being designed to run at increasingly higher speeds. In this article, the authors analyzed the thermal and moisture content profiles and their evolution in paper sheets during the fusing process. The thermal parameters for the paper sheets necessary for the model were obtained by independent measurements. Model predictions for the evolution of sheet temperatures were compared with experimental measurements in a commercial large print run copier in order to establish the validity of the model. Sheet temperatures on the image and reverse sides were measured at different points in a continuous run Xerox photocopier. Sheet surface temperatures depend on basis weight, caliper, coating level and filler levels. Coated or highly filled sheets showed higher temperatures, which persisted for longer times, whereas those of lower densities were cooler. Moisture redistribution effects within the short time scale of fusing were insignificant.