Moisture transport in paper passing through the fuser nip of a laser printer

Paper curls in printers should be prevented since they cause paper jams and degradation of printing quality. Moisture transport due to high temperature in the fuser nip of a printer is one of main reasons for paper curls. In order to predict and control the paper curls, it is therefore essential to understand the mechanisms of heat and moisture transport in paper. In this paper, we derived a coupled heat and moisture transport model and applied it to the situation where a paper sheet moves between two rollers having different temperatures in a fuser nip. A series of simulations were carried out with varying parameters related to the characteristics of printer paper, the environment, and paper/environment interfaces. The simulation results provided a deep understanding of the moisture transport mechanisms and identified several key variables affecting changes of moisture profiles as a function of time. The time-dependent moisture contents data will be fed into a mechanical model to obtain the quantitative amount of the nip curl.