ITRM950717A1 - SCREEN PRINTING ON CRYSTAL / GLASS AND TRANSPARENT OF ANY NATURE IN FOUR COLOR THAT MAKES THE IMAGE PRINTED TRANSLUCENT OR TRANSPARENT - Google Patents

Description

SCREEN PRINTING ON CRYSTAL / GLASS AND TRANSPARENT OF ANY KIND IN FOUR COLOR THAT

THE TRANSLUCENT OR TRANSPARENT PRINTED IMAGE ».

TEXT

This technique derives substantially from the printing method called "Screen Printing System" with specifically studied features and devices, described in detail below, which allow four-color reproduction on a material notoriously refractory to this printing system, crystal / glass.

FOUR-COLOR SCREEN PRINTING ON SILICEOUS SUPPORTS

The reason why a four-color translucent screen printing has never been performed on a support of siliceous origin, or rather it has been performed in non-translucent monochrome, can be deduced precisely from the chemical-physical constitution of the substrate to be printed. The two main reasons of difficulty for four-color screen printing on such substrates have been reported below:

1) The use and type of inks for the four-color reproduction of paintings and photographs. For this kind of reproductions it is essential to use screen printing frames or matrices made with natural fabrics (natural silk tumbler gauze), synthetic (nylon and polyester) or metal (stainless steel cloths) with very dense wefts, therefore by virtue of what said, the choice of inks and their drying method turns out to be fundamental for the achievement of the objective

2) D. electrostatic phenomenon during the printing phase on siliceous substrates, turns out to be a serious problem for obtaining an optimal print quality.

In fact the crystal / glass being a highly electrostatic material captures the dust present in the air compromising the complete adhesion of the printing paints and consequently also the quality of the latter.

Without going into the details of the screen printing technique, already abundantly known and bibliographically documented, we would like to focus instead on the techniques adopted for solving the problems listed in points 1 and 2 of this document:

1) Introducing the subject of inks, there is no doubt that the latter in the field of screen printing must possess, in addition to the general characteristics of density and fine grinding of the pigment that ensures its passage through the mesh of the cliché fabric, also specific characteristics that vary according to of the material on which they are to be printed.

It is interesting to point out that in screen printing a different ink must be used for each type of material on which to print, therefore the one used to decorate the polystyrene cannot be used to print on metal.

Screen printing inks can be divided into four groups according to their type of drying and the way of anchoring to the background material: IA) Drying inks by evaporation of solvents

IB) Oxidation drying inks ^

IC) Curing-drying inks

ID) UV drying inks

A) Drying inks by evaporation of solvents

To this group belong all those inks that have the property of attacking the material on which they are printed so that, once the solvent contained in them has evaporated, the pigment remains incorporated into the material itself. They cannot be used for printing on silicon-based materials

IB) Oxidation drying inks

Called greasy inks they are considered enamels, with excellent scratch resistance, excellent printability characteristics (i.e. they do not dry in the thinnest sections of the matrix even if a very dense mesh fabric has been used) and high ability to maintain the shades of the colors underneath unaltered. the action of atmospheric agents. They cannot be used for translucent prints

IC) Curing-drying inks

These inks are used on all those printing repellent materials such as glass, ferrous and non-ferrous metals, where there is an absolute need for adherence.

They are two-component inks (inchistro catalyst) which require relatively long waiting times to polymerize and have a tendency to change color tones and to discolour when exposed to sunlight. Furthermore, due to the presence of the catalyst, they are not suitable for printing with tightly woven fabrics such as those used in four-color printing.

1D) Drying inks by means of U.V.

In these inks, drying takes place by passing the printed support into an oven equipped with an ultraviolet light source. The great advantage of these inks, unlike those described above, is that they are solvent-free, thus allowing to print through matrices of very dense weft fabrics without drying in the thin sections. their use on non-transparent and screen print substrates generally allows to obtain results that are difficult to reach with normal inks.

In consideration of what has been said about the characteristics of the inks used for the screen printing system, it is clear how difficult it is to obtain a print on the crystal / glass that is:

1) Four-color

2) Translucent (transparent)

3) Faithful in shades of colors to the original to be reproduced

4) Unalterable to attack by atmospheric agents and over time. CONCLUSIONS

The result we obtained (see registered model table 1 was obtained empirically using, in the percentages described by us, three of the four groups of inks mentioned above:

TABLE 1 - Composition of the Inks Compound - Oxidation drying ink from 10% to 17% Polymerization drying ink from 5% to 9% UV drying ink from 70% to 90% DRYING PROCESS

The printing thus carried out, using the compound of table 1, on the support of siliceous origin, is directly or indirectly exposed to natural or artificial electromagnetic radiations ranging from 1 to 750 nm, at a controlled temperature and for a period of exposure of the duration from 1 to 10 seconds.

2) For the attenuation of the electrostatic phenomenon, due to the presence of dust on the printing surface, various solutions have been adopted: 2A) Use of a system of conductors that electrified with suitable direct voltages allow to attenuate the electrostatic phenomenon with the consequent elimination dust on the crystal / glass. 2B) Use of sterile environments ("clean room")

2C) Wiping of elect & izable materials placed in contact with the printing surface

2D) Use of a controlled suction system placed at a predefined distance on the printing surface

2E) Systems obtained from incubator machines

1) SCREEN PRINTING ON CRYSTAL / GLASS AND TRANSPARENT OF ANY KIND IN FOUR COLOR THAT MAKES THE PRINTED IMAGE TRANSLUCENT OR TRANSPARENT, characterized by the use of three groups of inks and by the use of a system for the attenuation of the electrostatic phenomenon and consequent partial elimination of dust on the crystal / glass.

2) SCREEN PRINTING ON CRYSTAL / GLASS AND TRANSPARENT OF ANY KIND IN FOUR COLOR THAT

Claims (3)

The printing thus carried out, using the compound of table 1, on the support of siliceous origin, is directly or indirectly exposed to natural or artificial electromagnetic radiations ranging from 1 to 750 nm, at a controlled temperature and for a period of exposure of the duration from 1 to 10 seconds. 2) For the attenuation of the electrostatic phenomenon, due to the presence of dust on the printing surface, various solutions have been adopted: 2A) Use of a system of conductors that electrified with suitable direct voltages allow to attenuate the electrostatic phenomenon with the consequent elimination dust on the crystal / glass. 2B) Use of sterile environments ("clean room") 2C) Wiping of elect & izable materials placed in contact with the printing surface 2D) Use of a controlled suction system placed at a predefined distance on the printing surface 2E) Systems obtained from incubator machines CLAIMS 1) SCREEN PRINTING ON CRYSTAL / GLASS AND TRANSPARENT OF ANY KIND IN FOUR COLOR THAT MAKES THE PRINTED IMAGE TRANSLUCENT OR TRANSPARENT, characterized by the use of three groups of inks and by the use of a system for the attenuation of the electrostatic phenomenon and consequent partial elimination of dust on the crystal / glass. 2) SCREEN PRINTING ON CRYSTAL / GLASS AND TRANSPARENT OF ANY NATURE IN FOUR-COLOR PROCESS THAT MAKES THE PRINTED IMAGE TRANSLUCENT OR TRANSPARENT, as in claim 1 characterized by the use, in the percentages reported below, of the following groups of inks: TABLE 1 - Composition of the Inks Compound - Oxidation drying ink from 10% to 17% Polymerization drying ink from 5% to 9% UV drying ink from 70% to 90% DRYING PROCEDURE The printing thus carried out, using the compound of table 1, on the support of siliceous origin, is directly or indirectly exposed to natural or artificial electromagnetic radiations included in the frequencies from 1 to 750 nm, at a controlled temperature and for a period of exposure of the duration from 1 to 10 seconds. 3) SCREEN PRINTING ON CRYSTAL / GLASS AND TRANSPARENT OF ANY NATURE IN FOUR-COLOR PROCESS THAT MAKES THE PRINTED IMAGE TRANSLUCENT OR TRANSPARENT, as in the previous claims characterized by the use of a system of conductors which electrified with suitable continuous voltages allow to attenuate the electrostatic phenomenon with the consequent elimination of dust on the crystal / glass. Alternative systems for the elimination of dust are: 3 A) Use of environment and / or sterile areas ("clean room") 3B) Rubbing of electrified materials placed in contact with the printing surface 3C) Use of a controlled suction system placed at a predefined distance on the printing surface E) Systems obtained from incubator machines