Thermal Printing on Composite Media

W.T. Vetterling
ZINK Imaging, Bedford, MA, USA

In direct thermal printing, media is exposed to heat pulses from a print head carrying a linear array of resistive heaters. In this study we investigate the degree to which a thin substrate can be combined with a more compressible sub-layer to provide a composite structure that will hug the heaters.
A 3D view of the model using COMSOL Multiphysics shows a section of the glass bump compressing a layered media. The colors represent the strain-field in a typical solution. We have modeled 3D slices of the print head with lateral dimensions up to 400 um, and observed the dependence of the heater-to-media contact length on the slice width. Results will be presented for the variation in heater contact with pressure for both uniform and patterned compressive sublayers.

The variation of compression with width for a very thin slice can be interpreted as an \"end-effect\", representing a real change in compression as we approach the end of a print head.