Selective Evaporation at the Nozzle Exit in Piezoacoustic Inkjet Printing

``Ugh, not again! Something's wrong with this printer\dots{}'' In inkjet printing the nozzles in the printhead have intermittent idle periods, during which the ink can evaporate from the nozzle exit. Inks are usually multicomponent, and each component has its own characteristic evaporation rate, resulting in concentration gradients within the ink that can alter the jetting process. Through experiments, analytical modeling, and numerical simulations, the authors unravel the complex physicochemical hydrodynamics associated with the drying of ink at a printhead nozzle.