PURPOSE OF THE INVENTION
The present invention refers to a new process for the ornamentation
of wall and floor tiles by making it possible to reproduce any type of design,
especially photographic motifs or images, on them.
The procedure permits the reproduction of such images in black-and-white
as well as colour.
ANTECEDENTS OF THE INVENTION
At the present time for the ornamentation of ceramic surfaces the
following processes are employed:
Single firing: The entire product is heated in the kiln once so that the unfired
base element or bisque receives the enamel using a sprayer and later the decoration,
via a serigraphic screen with a type of fixative being used between screens.
Double firing: First the base or bisque is fired, and then the coats cited
above are applied. It is then returned to the kiln.
Third firing: With this option first the bisque is heated, as in the previous
case, and then next, after applying the engobe as in the two previous methods,
we proceed to the enamelling and a new firing phase, with the final decoration
being applied with screens or by hand (by brush), proceeding finally to the "third
firing" which gives the process its name. The decoration in this "third firing"
system also tends to be done by applying pre-decorated treadles over the enamelled
There has recently appeared a system by which the entire process
of glazing, enamelling, and decoration using rubber rollers or something similar
without employing enamel sprayers or serigraphic screens.
At any rate, these approaches have their own disadvantages which
consist mainly in the following:
The surface area of serigraphic screens is very limited since, physically,
the holes where the paste must pass (coloured ceramic + liquid carrier) need to
be of large enough diameter for the paste to flow through with the ensuing danger
of that the orifices become quickly clogged. To mitigate this problem weaves of
very few threads should be used, causing a final image definition that is notably
The angling of each serigraphic screen is critical when working with liquid
paste, which tends to expand to some degree after passing through the orifice of
the screen, depending on the diameter of the points of the weave, the density
of the paste, and pressure and speed of the spatula. Other besides inconveniences
or defects are also suffered.
Defects registering the crosses of each screen over the former, due to the
very manufacture process, i.e., inherent in the process itself.
Thus, the present technological state in the area of application
of the invention shows an area of difficulty associated mainly with a lack of exact
registry and the consequent impossibility of working with elevated weaves in order
to obtain high-quality photographic images in the generation of weave points and
unequal point density and in the use of larger points in the process, the serigraphic
screen, with which still more point definition is lost, since it is probable that
a point of photolyte is found in the intersection between two threads of the screen
making it impossible to obtain a motif in the serigraphic panel identical to the
DESCRIPTION OF THE INVENTION
The procedure for the ornamentation of wall and floor tiles that
the invention proposes more than satisfactorily resolves the problem mentioned
above, insuring the perfect engraving of the images selected, in black-and-white
as well as colour; in glossy or flat finishes, with maximum durability and resistance.
For it, and more precisely, in a primary operative phase we proceed,
after selecting the image, to the digitalisation and processing of the same for
its photography in photolyte.
Next the transfer paper is laminated and insolated through photolyte
four-colour printing. This operation of lamination and insolation should be repeated
as many times as the number of colours to be used in the printing make necessary,
according to intention whether said printing is monochrome or polychrome, as previously
Next, in a third operative stage, a commonly used transport solution
is applied and allowed to dry. The enamelled ceramic support is cleaned, after
which it is fired at a maximum temperature of 1,050° C, a firing phase performed
at the same time as that of the tile so that the image becomes integrated in its
In agreement with the other characteristics of the invention, the
firing curve is to evolve in the following manner:
During the first hour the kiln temperature is raised from room temperature
to 325° C. At 2h.45min. a temperature of 700° C is reached. After 30 minutes more,
the temperature reaches 1,050° C, which is maintained for 10 minutes, only to
be lowered afterwards to room temperature for a period of 2h.30min.
A glossy or flat finish is achieved by incorporating more or less
flux into the ceramic colours so that they melt with more or less facility in order
to obtain more or less brilliance.
PREFERABLE EMPLOYMENT OF THE INVENTION
According to a preferred example of the practical use of the invention
and when dealing with the ornamentation of wall and floor tiles and with images
in colour, the image to be applied onto the ceramic piece in question is digitised
and processed. More exactly, filming in photolyte at 200 lines per inch, which
equals 78.74 points per cm2 is done.
The transfer paper is laminated and insolated by magenta four-print
photolyte. The protective plastic is removed from the treadle sheet to apply the
powdered magenta ceramic colour and the probe or treadle is instantly cleaned
with anti-static gauze.
Next this operation is repeated, i.e., a second lamination and insolation
is performed, following the same process, with cyan photolyte colour, a third with
yellow and a final one with black.
Afterwards, a commonly used transport solution is applied, either
by brush or serigraphic screen. After drying, the enamelled ceramic support is
cleaned. Then the probe or treadle is submerged in water to loosen the image from
the cardboard support. Once loosened, it is applied onto the ceramic piece, eliminating
the water and the air with a rubber spatula.
Once again, it is allowed to dry and then fired at high temperature,
concretely at 1,050° C in order to fire the colour of the image together with the
tile and integrate the image with the enamel of the latter. More or less flux
is incorporated into the ceramic colours according to the desired gloss.
When dealing with black-and-white images or sepia, the procedure
is exactly the same as described for obtaining those of colour except that only
one phase of lamination and insolation is carried out, i.e., in black or sepia.
In obtaining black-and-white images as well as those in colour the
firing curve is the following:
a) 350° C increase in one hour.
b) 700° C increase in 4'45''.
c) 1,050° C for 30 minutes more.
d) Maintenance at 1,050° C for 10 minutes.
e) Reduction to room temperature in 2h.45min.
As may be deduced from the above, the use of colours capable of supporting
the high temperatures mentioned is necessary in order to achieve greater durability
and resistance in the finish.
It is not considered necessary to elaborate this description any
further for any expert in the field to understand the achievement of this invention
and its advantages.
The terms in which this memorandum is made should always be taken
in the most ample and least limited sense.