Abstract
In drop-on-demand inkjet systems, nozzle clogging due to evaporation is our great concern. To study the drying process at the inkjet nozzle, we have developed a novel method for measuring the change of ink viscosity at the nozzle. In this method, ink viscosity is estimated by measuring the vibration of meniscus using a laser Doppler vibrometer and by verifying the measured results with calculations using an equivalent circuit model of inkjet head.
In order to understand the drying process, the changes of viscosity by the evaporation about a glycerol aqueous solution were simulated by a one-dimensional convective diffusion model and compared with the experimental results of viscosity measurements. The results of simulation show good agreement with experimental results. Thus, the drying process of simple liquid can be expressed well by the model. From the experimental and simulation results, it was revealed that the drying process shows two-step process;the drying process of the surface at the nozzle and the drying process of the pressure chamber.
