PRIMERS FOR INKJET DECORATION: MECHANISMS AND FUNCTIONINGS
Ceramic industry is today inseparably linked to the use of digital printer machines that involve the use of pigmented liquid inks.
These new production systems have therefore required the development of specific mediums able to improve the printing process in terms of definition and colour rendering as well as to reduce possible defects deriving from the printers themselves.
These products affect specific production parameters and they take especially action on the absorption values of the ceramic support: both on raw tiles (porcelain stoneware production) or fired tiles (double-firing production).
In both cases, the use of PRIMER must precede the ink’s application in order to create the ideal precondition for the following decoration process.
The product can be added as it is to the glaze in the stirring system of the glazing line or diluted in water and applied on the glaze’s surfaces with fine spray airbrushes that allow a uniform application.
The mechanism of action – that does not modify the glaze’s rheology – is focused on the ability to create a controlled absorption of the ink on the glazed support.
Speaking of porcelain stoneware, primers are in general able to produce an invisible film that stabilize and correctly manage the ink’s drop in contact with the glaze.
We may somehow say that, thanks to their activity, inks do not expand on the support assuring a high-printing definition: the draining capacity of the raw glazed tile is basically reduced and this reduction ranges according to the applied quantity.
In general, increasing the dosage corresponds to a reduction in the rate of absorption.
The use of these kinds of mediums also reduces defects resulting from inexact adjustment of the printing heads.
In the case of double-fired products, the vitrified surface of which is completely impermeable, the film creation is requested in order to provide the surface with the absorption properties that can guarantee the correct application of the inks, therefore ensuring the pigments to be correctly fixed.
As always happens in the world of additives, also in this case, primers must be formulated based on the different application lines and the involved raw materials so to ensure an optimal result according to the specific customer’s needs.
Check the images at the top of the post.
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