Tatiana Sretentseva, Julia Timchenko

Abstract
This paper is devoted to the investigation of the influence of the composition, functionality, nature and rheological characteristics of the model vehicles on rheological properties (anomaly of viscosity, the yield stress Pk) of model UV curing inks for screen printing. Also we have studied the dependence of the rheological characteristics of model inks (viscosity, yield stress, structuring degree, structure strength, rate of destruction and reconstruction of the structure, rate of thixotropy) on concentration and functional features of a number of pigments added to the ink compositions.

Keywords: rheology, yield stress, anomaly of viscosity, thixotropy, screen printing inks.
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Juha Saari, Roger Bollström, Ken Mueller, Martti Toivakka

Abstract
The multi phase ink setting mechanism gives new insight into lithographic sheet fed offset ink modifi cations. The ink setting in sheet fed offset is by absorption and oxidation and the inks have a relatively high tack. Because of the wide variations in sheet-fed offset ink formulations the ink to paper interactions are extreme. The problems related to ink setting is mainly set-off (slow setting), mottling (ink setting variations), ink tack build up and surface strength problems (fast setting) and other print quality defects that can be caused by paper variations, print variations, slow/fast ink setting, dusting, base paper and coating structure, etc. The trend for more porous coatings with better whiteness, printed colour gamut, and light scattering properties will require ink modifi cation to control the ink setting phenomena. It is assumed that by changing the resins, solvents etc. of the printing ink, it is possible to adjust the ink setting in such way that the printing result is good for papers with different coating porosity volumes and porosity size distributions.

Keywords: Ink setting, Sheet-fed offset, Multiple-phase mechanism, Coated paper, Porosity
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Verónica Marchante, Francisco Martínez-Verdú, Elena Marchante, Juan Antonio Maciá, Elisabeth Chorro, Esther Perales, Vicente de Garcia, Jesus Inarejos, Susana Otero

Abstract
Nanopigments are a new type of pigment. They are hybrid materials consisting of organic dyes and layered silicate nanoparticles. Nanopigments are already applied to make polymeric coatings and they had shown improvement in mechanical, thermal and stability properties of the substrate and dyes (Batenburg and Fischer, 2001).

In this work, nanopigments had been synthesized to be applied in the manufacture of offset printing inks. Therefore, four different nanopigments are pursuit: cyan (C), magenta (M), yellow (Y), and black (K), in order to obtain primary colour for a four-colour-process system.

Keywords: Colorimetry, Nanopigments, Offset printing inks.
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