A numerical, finite-difference model has been developed to simulate the dye-transfer thermal printing process. This model was used previously for calculating the amount and depth of the dye diffusion going into a receiver and for estimating the printing line times required for the dye transfer processes. The simulation incorporates the multiple layers of the head/media interface and uses finite-difference techniques to calculate temperature and mass distributions. Surface-boundary conditions have been determined from experimental printhead temperature data. The concentration dependence of the diffusivity is taken into account, and this leads to a nonlinear governing equation.As one increases the amount of power delivered by the thermal head, larger quantities of dye will be transferred into the receiver. In a similar fashion, any changes to the dimensionality and/or thermal properties of the materials comprising the donor and receiver will affect the temperature distribution. This, in turn, will cause the amount of dye transfer to change. These changes have been investigated, and the predicted amounts have been calculated for dye transfer. Comparing the amount of calculated dye transfer from known operating conditions, one is able to predict the amount of time required for an equivalent transfer to occur. The efficiency of heat transfer for a typical thermal resistive head is low (∼15%). Producing a more efficient printhead will enable equivalent quantities of heat to be transferred at lower applied voltage levels. At the same voltage levels, larger amounts of heat transfer will result in faster printing speeds. Situations are analyzed for current thermal printer materials, and predictions are made for reduced printing time requirements.
Edward J. Ozimek, "Use of Thermal Dye Diffusion Model to Predict the Effects of Increased Thermal Printhead Efficiency" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP20), 2004, pp 984 - 987, https://doi.org/10.2352/ISSN.2169-4451.2004.20.1.art00099_2