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(11) | EP 2 143 568 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | A process for cold-painting laser engravings applied on a slab cladding element |
| (57) A process for cold-painting laser engravings applied on a slab cladding element (1),
comprising following stages: depositing an insulating substance (2) on the in-view
surface (1a); engraving a decoration (3) on the in-view surface (1a) by means of a
laser (4); laying a colouring substance (5) on the in-view surface (1a); spreading
a colouring substance (5) on the in-view surface (1a); and removing the colouring
substance (5).
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[0001] The invention relates to a process for cold-painting laser engravings applied on a slab cladding element.
[0002] By the term cladding element, tiles and ceramic manufactures in general are intended, including cotto, marble, granite, glass, wood and other materials of any nature for cladding walls or floors.
[0003] The process is therefore applicable to the ceramic industry, the wood industry, mills and other industries working on cladding materials.
[0004] In the ceramics sector, producing tiles or any other cladding element with decorations on the in-view surface is a common and consolidated activity.
[0005] Present techniques for producing decorated tiles include, in one case, realisation of the decoration during the graphic designing of the in-view surface of the tile, and in another case, realising the decoration downstream of the production process.
[0006] In the first case the tile production is serial, and consequently cannot include further modifications, or customisations requested by the consumer.
[0007] In the second case the production of tiles can be either in series, a situation that occurs when the preselected decoration is for example the trade mark of the producer, or can be specialised, which is when the consumer requests, for example, a batch of tiles with customised decorations; but it can also be a single piece exhibiting an original decoration.
[0008] From among the various production processes in the second case, for economic reasons realisation of a decoration on a tile by removal of material is preferred.
[0009] The most widely-used processes used in the ceramic field for removal of material for decorative purposes include use of a laser for engraving the decoration on the in-view surface of the tile.
[0011] One laser decorating process includes a stage of realisation a computerised graphic of the decoration, with a computer reading graphic data and transforming it during a work cycle, and realisation of the decoration via laser incision.
[0012] For series-produced laser-engraved tiles with coloured decorations, production is normally performed by intermediary second- or third-firing producers.
[0013] The expression "second- or third-firing producers" refers to the fact that the tiles are subjected to further heating in special kilns.
[0014] During the production process the decorative painting is done before, using a localised depositing on the in-view surface of a colouring substance, and then by subsequently heating the tile in special kilns in order to fix the paint on the decoration.
[0015] The in-view surface can exhibit decorations or reliefs or rough engraving done using sanding techniques.
[0017] The heating of the in-view surface of the tile causes a change in the original colour of the tile coming from the producer and the final colour of the tile coming from the second- or third-firing companies.
[0018] The above situation leads to the impossibility of laying, for aesthetic reasons, decorated tiles close to original non-decorated tiles and therefore leads to the necessity for the producers to outsource tile ranges which might include decorations to third parties.
[0019] An economical compromise for the producers is to engrave the laser decoration without colouring it, exploiting special chromatic tones on the in-view surfaces which generally exhibit a dark background.
[0020] This decoration is visible thanks to contrast effects between the in-view surface and the engraving which is generally discoloured, substantially tending to grey.
[0021] With other types of slab elements, such as for example cotto or wood, the contrast between the in-view surface and the engraving exists in relation to the fact that the decoration exhibits a chromatic tone which is different with respect to the original colour of the slab element.
[0022] These phenomena are caused by the high temperatures reached by the laser. In the case of slab elements such as tiles, the working temperatures of a laser fuse the in-view surface of the tile and by penetrating into the tile reach the internal ceramic mixture which, as well as reacting differently to the laser treatment with respect to the external surface and therefore having a different colour, might also exhibit traces of ferrous materials which enhance the above-mentioned phenomena of contrast.
[0023] In the case of cotto or wooden slab elements, the operating temperatures of a laser are such as to fuse the in-view surface and the recesses of the decoration are substantially burned and thus are of a darker colour which is in contrast with respect to the original colour of the in-view surface.
[0024] The contrast between the bottom of the engraved part and the external surface of the tile is however less evident when the tile exhibits a light-coloured bottom or background surface.
[0025] The aim of the present process is to realise a process for cold-painting laser engraving applied on slab cladding elements.
[0026] A further aim of the present process is to obtain a colouring of the decoration without changing the chromatic tones of the in-view surface.
[0027] A further aim of the present process is to realise decorative colouring having monochromatic or multi-chromatic tones.
[0028] These aims and advantages and more besides are attained by the process of the invention as it is characterised in the appended claims.
[0029] Further characteristics and advantages of the present process will better appear from the detailed description that follows of a preferred but not exclusive embodiment of the invention, provided by way of non-limiting example in the accompanying figures of the drawings, in which:
figure 1 is a first stage of the process for cold-painting laser engraving applied on a slab cladding element of the present invention;
figure 2 is a second stage of the process relating to the laser engraving;
figure 3 is a third stage of the process relating to the cold-painting of the laser incision;
figure 4 is a fourth stage of the process relating to the cleaning of the slab element.
[0030] With reference to the figures of the drawings, 1 denotes a slab cladding element for walls or floors.
[0031] The cladding element can be of any polygonal or curved shaped, can be regular or irregular and can be constituted by any material such as for example ceramics, cotto, marble, granite, glass and wood.
[0032] The cladding element 1 includes an in-view surface 1a opposite a laying surface which is in contact with the wall or floor to be clad.
[0033] The process for cold-painting laser engravings applied on slab elements comprises a first stage of depositing an insulating substance 2 on the in-view surface.
[0034] This depositing stage, which is obtained in a chamber using a spray gun with a plurality of nozzles 6 facing the in-view surface 1a and illustrated in figure 1, generates an insulating film 10 on the in-view surface 1a which film 10 has a substantially constant thickness along the whole in-view surface 1a.
[0035] Thereafter, following the graphic designing of a decoration 3 to be made on the in-view surface 1a, the decoration 3 is obtained by a laser pointer 4, as illustrated in figure 2.
[0036] During this stage of the work the laser pointer 4 creates a plurality of engravings forming the decoration 3.
[0037] The operating temperatures of the laser pointer 4 fuse the layer of insulating film 10 previously formed thereon, and at the same time the laser pointer 4 penetrates the in-view surface 1a to a depth established on the basis of design needs or decorative requirements.
[0038] The stage following the realisation of the decoration 3 is that of laying a colouring substance 5 on the in-view surface.
[0039] The colouring substance 5, for obvious economic reasons, will be laid in the strict vicinity of the just-realised decoration 3.
[0040] This colouring substance 5 is preferably defined by a cold resin acting on the in-view surface 1a without any need for application of heat.
[0041] Then the colouring substance 5 will be spread in order to obtain a layer of film 11 and thus a more uniform distribution on the in-view surface 1a will be obtained.
[0042] This work stage is also done in order to guarantee that the colouring substance 5 entirely covers the decoration 3.
[0043] The distribution of the colouring substance 5 can be done manually by use of at least a spatula 7 or industrially by motorised means such as for example brushes or screens.
[0044] In manual distribution lumps of colouring substance can be found which have not been properly spread and which can be manually removed by scrapers, not illustrated in the accompanying figures of the drawings.
[0045] After leaving the colouring substance 5 to dry on the in-view surface 1a for about 48 hours, it is removed.
[0046] The final stage of the process is thus performed, i.e. the removal of the colouring substance 5 from the in-view surface 1a.
[0047] This removal is done with at least a motorised brush 8, illustrated in figure 4, exhibiting a plurality of textile fibres which do not damage the in-view surface 1a.
[0049] The above-described process is to be considered valid in both a case in which the decoration exhibits a single chromatic tone and in a case where the decoration includes more than one chromatic hue.
[0050] Let us take, for example, a case in which the decoration 3 is sub-divided into a first part 3a and a second part 3b.
[0051] The process will include the repetition of the sequence of stages as described above for each part 3a, 3b making up the decoration.
[0052] When first part of the decoration 3a has been coloured, the insulating substance 2 will be deposited, the second part of the decoration 3b engraved and then coloured with a further colouring substance, and finally both colouring substances will be removed by use of at least a motorised brush 8.
1. A process for cold-painting laser engravings applied on a slab cladding element (1),
the slab element (1) exhibiting an in-view surface (1a), which slab element (1) is
characterised in that it comprises following stages:
depositing an insulating substance (2) on the in-view surface (1a);
engraving a decoration (3) on the in-view surface (1a) by means of a laser (4);
laying a colouring substance (5) on the in-view surface (1a);
spreading a colouring substance (5) on the in-view surface (1a);
removing the colouring substance (5) from the in-view surface (1a).
2. The process for cold-painting laser engravings applied on a slab cladding element
(1), characterised in that the process includes, following the stage of removing the colouring substance (5)
from the slab cladding element (1), a stage of insulating obtained by further depositing
an insulating substance (2).
3. The process for cold-painting laser engravings applied on a slab cladding element
(1) of claim 1, characterised in that the stage of depositing the insulating substance (2) is obtained using a plurality
of nozzles (6).
4. The process for cold-painting laser engravings applied on a slab cladding element
(1) of claim 1, characterised in that the insulating substance (2) is preferably a non-stick substance.
5. The process for cold-painting laser engravings applied on a slab cladding element
(1) of claim 1, characterised in that the stage of spreading the colouring substance (5) is obtained using at least a spatula
(7).
6. The process for cold-painting laser engravings applied on a slab cladding element
(1) of claim 5, characterised in that the colouring substance (5) is a resin.
7. The process for cold-painting laser engravings applied on a slab cladding element
(1) of claim 1, characterised in that the stage of removing the colouring substance (5) is obtained using at least a motorised
brush (8).
8. A process for cold-painting laser engravings applied on a slab cladding element (1),
the slab element (1) exhibiting an in-view surface (1a) on which a decoration is to
be made, whch decoration is defined by a first part (3a) and a second part (3b), the
process being characterised in that it comprises following stages:
depositing an insulating substance (2) on the in-view surface (1a);
engraving a first part of a decoration (3a) on the in-view surface (1a) by means of a laser (4);
spreading a first colouring substance (5) on the in-view surface (1a);
depositing an insulating substance (2) on the in-view surface (1a);
removing the colouring substance (5) from the in-view surface (1a);
engraving a second part of a decoration (3b) on the in-view surface (1a) by means of a laser (4);
spreading a second colouring substance (5) on the in-view surface (1a);
removing the colouring substance (5) from the in-view surface (1a).