Liquid droplet imbibition into a paper coating layer: direct pore-scale modeling and experimental observations

Abstract:

In this presentation, we provide results of a combined numerical/experimental study of the penetration of an ink droplet into the paper during inkjet printing. We present results of an advanced visualization technique and pore-scale two-phase simulations. As visualization technique, confocal laser microscopy imaging was integrated into a FIB-SEM chamber. This is the first time that this combined technique is developed and used. This technique allows us to obtain high resolution images of the liquid movement inside a paper coating layer. This process was also simulated using OpenFoam simulator. This simulator sovles Navier-Stokes equation for incompressible liquids based on Volume of Fluid method. For the simulation domain, the high-resolution three-dimensional structure of the paper was obtained via focused ion beam scanning electron microscopy (FIB-SEM). We could simulate the movement of water or an ink-like liquid into the pore space satisfactorily. We found good agreement between imaging and simulation results regarding the ink penetration and spreading extent. Therefore, we used the simulation model to study effects of liquid contact angle, real ink properties, and droplet arrival velocity on paper surface on the final print quality.