Thermal Properties of Copy Paper Sheets

The thermal conductivity and specific heat of paper are important in determining its response to heat pulses encountered in applications such as copying or digital printing. This work reports measurements of the thermal conductivity, contact resistance, and specific heat for a number of commercial copy paper sheets. The experimental setup was designed to measure transient and steady-state temperature distribution in stacks of paper sheets from which the thermal properties were determined. Steady-state measurements of the temperature difference were used to determine the thermal contact resistance and the thermal conductivity of the sheets. The specific heat was determined from the transient temperatures recorded during heat-up and cool-down periods. The thermal conductivity depends upon the sheet density, filler content, and nature of the fibers. It also showed a small increase with temperature of approximately 10(-4) W/(mK)/K. Models of thermal conductivity based on the resistance of the fibers and the fillers were developed. The thermal contact resistance increased with the surface roughness as measured by the Gurley permeability (referring to surface roughness). The specific heat of paper was dependent on its ash content.