The invention relates to a procedure to differentiate between the
images printed on any material, in particular ceramic tiles, and a device to carry
out the said procedure.
One of the elements which used to confer a particular beauty to images
reproduced using craft techniques, even on the most varied types of materials,
was undoubtedly the fact that although the said images depicted the same subject,
they were never identical.
This particularity was due to the fact that the printing process
carried out were comprised mainly of manual operations and also that the mechanical
means available to the craftsmen left a lot of freedom for approximation and deviations
from what could be called an average value.
While, on the one hand, industrial procedures have made mass production
of printed materials of various types possible, on the other hand they have also
marked the end of the imprecision and the inequality of the crafted prints. Consequently,
they have also marked the end of the beauty of the images obtained using the craft
techniques, which were always unique.
All of this becomes of maximum importance when considering the particular
field of images, especially patterns, printed on ceramic tiles to be used for decorative
purposes in the building industry.
In this field, in fact, the production has reached quantity levels
of enormous proportions.
For some time now, even in this field, there has been a need to realise
new production methods capable of printing images with aesthetic features similar
to those produced using the craft techniques. In particular, there has been a need
to realise tiles which, although bearing the same design, do not repeat it in the
same position, while still safeguarding the principle of industrial, mass production,
which obviously cannot be abandoned in today's production system.
For some time, then, we have experienced the conception and introduction
of machines capable of differentiating between the images, in particular the patterns,
printed on tiles, indicating, with the said specific term, the printing of identical
images but positioned differently on each support body, or the images which are
similar but not identical.
Until now, the differentiation of the printed images was carried out
by the procedure of moving the material before it arrived in the printing area.
This movement was made perpendicular to the direction in which the said material
was being fed.
It is clear that the images on the printed element are larger widthways
than the material and therefore, by moving the said printing element, a part of
the total image is printed on the material itself. By varying the movements made,
then, the pieces of material are printed with different designs.
A particular case of this type of differentiation between the images
is the application, on the same support body, of several colours, each one applied
by a specific station and in sequence. This particular case of differentiation
is called "shade varying process".
This procedure has some drawbacks, the first of which is the complexity,
and consequent cost, of the devices designed to carry out the aforementioned movement
of the bodies since, in some cases, including the case of tiles, the masses to
be moved are enormous.
Another drawback of the commonly known technique is the need to place
two devices along the same production line which will move the bodies, the second
of which is necessary to bring the said bodies of material, just after they have
been printed, onto the original production line. Consequently, the technical problems
and costs are doubled.
The commonly known technique has a further drawback which is that
the aforementioned movement to effect the differentiation does not involve individual
bodies but a rather considerable number of these pieces of material, with the consequent
division into lots of the differentiated units and, in this way, devaluing what
it was intended to create, i.e. bodies which are all printed differently.
A further drawback of the known differentiation techniques, in particular
in the ceramic tiles field, is due to the fact that the tiles themselves, because
of the materials they are made of, are decidedly fragile, especially the single-fired
tiles. It is clear that when moving particularly fragile objects there is a high
risk of damaging them and, therefore, of production waste.
A first aim of this invention is to present a new differentiation
procedure which is conceptually different from the one which has been used until
A further aim of the present invention is to make available a device
capable of differentiation using the aforementioned new procedure in order to
simplify the technical side of the production of the bodies, in particular body
ceramic tiles, with differentiated images, and to obtain considerable savings in
the production, in terms of both the reduction of waste from the finished product
and the savings on equipment costs.
In particular, the procedure object of the present invention is characterised
by the fact that a commonly known printing element can be moved randomly and orthogonally
to the feeder axis of the bodies to be printed, the said movement being designed
to result in the random positioning of the printing on the said bodies.
This and other characteristics will better emerge from the detailed
description that follows of a preferred embodiment, provided in the form of a
non-limiting example, with reference to the accompanying drawings, in which:
- Figure 1 shows a side view of the only elements that characterise the present
- Figure 2 shows a plan of the same elements as in figure 1;
- Figure 3 shows the same elements as in figure 1 but connected to a printing
unit of a commonly-known type;
- Figure 4 shows the same elements as figure 2 but these are also connected to
a commonly known printing unit;
- Figure 5 shows a frontal view of the elements shown in figures 3 and 4;
With reference to all the figures, the left/right arrow A indicates that a printing
element of a commonly known type has been moved; in figures 3 and 4, this printing
element is screen-like.
According to the procedure object of the present invention, the movement
indicated by the left/right arrow A only concerns the printing element 1 and is
only orthogonal to the feeding direction of the tiles 2 on the production line
indicated by arrow B.
With regards to the procedure and with reference to all the figures,
3 indicates a framework, substantially U-shaped, fitted with two sliding guides
4; the said guides are both flat and are positioned between the framework and a
fixed frame 5.
Integral to the two parallel arms of the aforementioned framework
there are two uprights 6 which, by means of some clamps 7, are also attached integrally
to two rods 8; the said rods connect the plates 9 which enclose the printing element
The rods 8 and the plates 9 are also of a commonly known type.
A hydro-pneumatic motor element 10 has its own output shaft attached
to the framework 3; the said motor element is positioned with the longitudinal
axis parallel to the sliding guides 4.
The tiles 2, as shown in the figures 3, 4, and 5, are supported by
some belts 11 of a commonly known conveyor and one of the said plates is in contact
with the lower side of the external surface of the printing element 1.
The functioning modes of the invention will now be described with
reference to numbers indicated in the figures.
When the tile conveyor has been started up, the tiles will reach the
area beneath the printing element 1.
At the same time, the motor element 10, following a electronic program
set previously by the operator, will determine a random movement of the framework
3 along the sliding guides 4 on which the framework itself is mounted.
The aforementioned random movements of the said framework are transmitted,
in identical form, to the printing element 1 since this is attached integrally
to the framework 3.
The impulses which determine the individual movements of the framework
3 are supplied by the motor element 10 in synchronism with the feeding of the tiles
2; the aforementioned framework only moves, therefore, when the there are no tiles
2 underneath the said printing element.
In this way, then, every tile 2 will be printed with a part of the
image in a different position to the previous tile.
The rotation of the printing element around its own axis, on the
other hand, is driven by a second motor element 12 illustrated in figure 1 and
which is a commonly known type.
If the image to be printed is composed of several colours, each tile
2 will be taken up by other printing differentiation devices, without ever leaving
the normal production line, the said devices being identical to those described
herein and being positioned along the tile production line and equal in number
to the colours the image to be printed is composed of.
In the description, specific reference has been made to tiles as the
bodies 2 on which the printing differentiation will be carried out, but it is
clear that the procedure and the relative device which is the object of the present
invention can be applied easily to bodies of a different kind and consistency.
Again, in the description, specific reference to a screen-like printing
element 1 has been made, but obviously, the device in question in this invention
can also be applied easily to any kind of printing element.
An initial advantage of the procedure described in this invention
lies in the fact that a part of the total image printed on the printing element
1 is transferred on each ceramic tile, or any other kind of support body, in such
a way that, by moving the said printing element transversally, the image printed
on each support body will be different from the previous one.
A further advantage lies in the fact that with the procedure illustrated
herein, damage to the tiles is prevented and so therefore is waste, since the tiles
themselves are never moved away from the normal production line.
A still further advantage of the device in question in this invention
is that the tiles can also be printed normally, without a differentiation of the
images since, this can be achieved by simply disengaging the motor element 10.