METHOD AND DEVICE FOR FLEXOGRAPHIC PRINTING USING ENERGY-HARDENED LIQUID PAINTS Russian patent published in 2008 - IPC B41F5/24 B41F33/00 B41M5/00 

FIELD: method and device for colored flexography.

SUBSTANCE: method for applying multiple paint layers onto a substrate includes following stages: application onto a substrate of at least one painting layer of energy-hardened liquid paint with viscosity less than approximately 4000 centipoises, and including reaction-incapable paint thinner, where applied layer of energy-hardened paint has first viscosity; evaporation of at least a part of reaction-incapable paint thinner from applied paint layer for increasing viscosity of applied layer of energy-hardened paint; application onto substrate and applied layer of energy-hardened paint with increased viscosity of at least one layer of non energy-hardened liquid paint, viscosity of which is less than increased viscosity of previously applied layer of energy-hardened paint; and drying of both paint layers on the substrate. Another variant of method for applying multiple paint layers onto a substrate is differentiated by applied layer of energy-hardened paint having to be of increased viscosity compared to following layer of energy-hardened liquid paint with viscosity less than approximately 4000 centipoises, and containing reaction-incapable paint thinner, where viscosity of following layer is less than increased viscosity of energy-hardened paint layer applied beforehand. Also a method is suggested for printing multiple paint layers on a substrate, which includes stage of selection of first and second energy-hardened liquid flexography paint, where each paint contains viscosity controlling reaction-incapable paint thinner, consisting of water in amount of from 5% to 50% of thinner weight, where each paint has viscosity approximately ranging from 30 to 70 centipoises, and stage of serial application of first and second energy-hardened liquid flexography paint onto a substrate to create first and second paint layers, having overlapping parts, where second paint is applied only after at least a part of paint thinner is evaporated in first paint layer. Device for serial application of multiple overlapping paint layers onto a substrate contains substrate route and substrate drive for moving the substrate along a route, where paint application sections are adapted for applying paint onto substrate, which paint includes reaction-incapable paint thinner and has viscosity less than 4000 centipoises, and also management system, which manages transportation of substrate along a route. Viscosity of first layer of liquid paint, applied onto a substrate in one of paint sections, is increased due to evaporation of at least a part of paint thinner from first paint layer to higher viscosity compared to viscosity of second paint, applied on top of first paint layer in next paint section, located at a certain distance from first paint section, up to viscosity, sufficient for "crude" application of second liquid paint layer during transportation of substrate between paint sections.

EFFECT: in suggested methods, relief printing is achieved without insignificant modifications of printing equipment.

4 cl, 2 dwg