Date of Award

5-2001

Level of Access

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Chemical Engineering

Advisor

Douglas W. Bousfield

Second Committee Member

Adriaan R.P. van Heiningen

Third Committee Member

Yang Xiang

Abstract

Inkjet printing is a popular non-impact technology with widespread use in home and office applications. The basic principle involves propelling ink drops of different colors on a substrate. High quality images, near photographic quality, are now possible. The gloss of the printed substrate is an important quality attribute. Printed gloss depends on a number of characteristics of the media and the ink, but a good fundamental understanding is not available in the literature. The dependence of the gloss on the media and ink characteristics is reported in this work. The experimental results are compared with values predicted by a mathematical model. The dynamic post-printing gloss was studied with a specially constructed apparatus, which measured the laser reflectance of the printed surface within 40 ms after drop impact. Both pigmented and dye-based inks are used with rapidly absorbing porous media and swelling polymer-coated media. Various properties of the media such as surface roughness, ink absorption rates, pore size distribution, oil absorption capacity, wettability, and gloss were characterized along with ink properties like surface tension, viscosity, and filtercake resistance or the "filtercake" forming ability of the pigmented inks. The model and experimental results show that the gloss of dye-based inks on porous media depends on the media roughness. Gloss on swellable media depends on the roughness of the wet swollen polymer coating. The gloss of pigmented inks on porous media is determined by the ink pigment size and the dry media gloss. The gloss on swellable media is determined by ink pigment size and the wet roughness. The model predictions compare well to experiments for a wide range of parameters.

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