Measurements and dimensional scaling of spontaneous imbibition of inkjet droplets on paper

Dimensional Scaling of Aqueous Ink Imbibition and Inkjet Printability on Porous Pigment Coated Paper–A Revisit

“…For the present case using microliter size droplets, unlike previous , cases using picoliter size droplets, it may be so that neither inertia or gravity terms can be neglected. We therefore need to estimate the dimensionless prefactors but realize the complication that we do not know p c and k separately but only the product from eq .…”

“…The aim of this investigation is to employ recent dimensional scaling of liquid and inkjet ink imbibition into porous substrates , onto earlier published data , that relate ink penetration to inkjet printability. Despite the tremendous importance of liquid imbibition in inkjet printing, based on the fact that up to 80–90% of the ink is liquid, the literature directly relating imbibition data to printability under the same experimental conditions is lacking.…”

“…The characteristic time t c , length l c , and velocity w c are defined and discussed elsewhere . In order to calculate the respective prefactors we need to measure or estimate the permeability and pressure terms k and p c , which we do not know separately but the product kp c can be calculated from the maximum penetrated depth h and corresponding time t ⊥ according to To allow relevant evaluation of penetrated depth, we assume that flow inside the coating is unidirectional transversal and not radial.…”

“…We developed a dimensional scaling starting from fluid motion equations that when applied to inkjet flow conditions could neglect inertia and gravity for imbibing picoliter-size droplets and thus arrive at Darcian flow. This was used first on homogeneous isotropic porous media with simple fluids , and second on paper substrates with inkjet ink fluids . The product of permeability k and capillary pressure p c was suggested as primary parameter governing ink imbibition and to be a predictor of printability but no relation to printability was given so far.…”

“…This was used first on homogeneous isotropic porous media with simple fluids 15,16 and second on paper substrates with inkjet ink fluids. 17 The product of permeability k and capillary pressure p c was suggested as primary parameter governing ink imbibition and to be a predictor of printability but no relation to printability was given so far. We revisit an earlier investigation, 18,19 in which laboratory prepared inkjet receptive mineral pigmented paper coatings were evaluated for their inkjet printability (color gamut area), however no physically correct treatment of flow and materials properties in relation to inkjet printability was offered.…”