WO2002038450A1

WO2002038450A1 - System for decorating ceramic goods

Info

Publication number: WO2002038450A1
Application number: PCT/EP2000/011110
Authority: WO
Inventors: Zeno Meglioli; Giorgio Brighenti
Original assignee: Dedra S.P.A.
Priority date: 2000-11-09
Filing date: 2000-11-09
Publication date: 2002-05-16
Also published as: AU2001221570A1; BR0016933A

Abstract

A machine for decorating supports (4) that comprises applying means (2, 4, 38, 38a, 38b, 102, 134, 136, 137, 144, 155, 158) arranged in order to apply decorating sheet means (18) to said supports (16) that are carried by a conveying line (14, 56), wherein said applying means (2, 4, 38, 38a, 38b, 102, 134, 136, 137, 144, 155, 158) cooperates with reference means (34) on said line suitable to maintain each support (16) in an applying station (102a, 103, 103a) while said applying means (102) press on it one said decorating sheet means (18) in order to cause it to adhere thereto. A method for decorating already formed ceramic supports (16), that comprises associating decorating sheet means (18) to an already formed ceramic support (16), said associating being carried out before sending to firing said support (16) associated to said decorating sheet means (18). A method for decorating supports (16) applying thereto decorating sheet means (18) that comprises advancing said supports (16) along a direction (F, Y) and applying on each one of said supports (16) one said decorating sheet means (18) through motorized applying means (2, 4, 38, 38a, 38b, 102, 134, 136, 137, 144, 155, 158).

Description

SYSTEM FOR DECORATING CERAMIC GOODS

The invention relates to the decoration of ceramic supports, particularly the decoration of type resulting from the use of decalcomanias suitable to be applied on ceramic supports in order to give them specific features of aesthetic and/or functional order.

A manual system for the application of decalcomanias on ceramic tiles already formed and fired is already known, wherein it is provided that the decalcomanias are singularly applied on a face of a ceramic support; subsequently the combination of support and decalcomania is fired in kiln in order to fix permanently the decoration to the support itself. Such process,^' commonly named "twice firing", shows the drawback of being very onerous because it requires that the supports are introduced in kiln according to two subsequent steps, the first one in order to fire the support, the second one in order to fix the decoration.

Before the application to the ceramic support, the decalcomanias are immersed into water in order to disengage them from the respective sheets. The decalcomania without the supporting sheet is quite delicate and must be handled with utmost care.

Therefore, this manual system for applying decalcomanias to supports involves a remarkable waste of time and use of manpower .

In order to get over the disadvantages connected to the necessity of firing the supports and the decoration in two subsequent steps, decorating methods were set up wherein the decalcomanias are comprised into the moulds of the presses where the ceramic supports are formed.

The state of art comprises the Italian patent IT 1236417 wherein a method is described for inserting decorations in the body of pressed ceramic products in which it is provided silk- screening, on a supporting sheet of polystyrene coupled with a paper sheet, ceramic powders previously selected, fired, blent into vehicle suitable for silk-screening, refined and homogenized, in order to obtain thereon a decoration, subsequently removing the paper sheet leaving the polystyrene sheet connected to the decoration, then introducing the supporting polystyrene sheet into the cavity of a ceramic mould, filling the cavity with ceramic powders, extracting from the cavity the ceramic manufacture, including pressed powders and decoration still fixed to the supporting sheet of polystyrene, and sending such manufacture to drying and firing.

Alternatively, the decoration connected to the supporting polystyrene sheet is introduced into a cavity of ceramic mould after powders of the tile to be formed were reversed in that cavity and said powders were partially pressed. In both cases, the pressed manufacture, comprising the above mentioned decoration, moves towards the drying and firing, having the supporting polystyrene sheet still connected with it.

Therefore it happens that, because the decoration strongly adheres to the supporting polystyrene sheet, during pressing it does not suitably integrate with the powders of the tile to be formed, or rather in prevalent manner the tendency occurs to detach from them, that originates production scraps. Furthermore, from the drying and firing of the formed manufacture with the supporting sheet connected thereto, further finishing defects of the product originate, because the combustion of the supporting sheet can leave residues that trend to mix with the decoration, damaging it. The state of art further comprises the Italian patent IT 1262643 wherein a method is described to insert glass-based decorations into the body of ceramic products. This method provides silk-screening on a supporting paper sheet, on subsequent stages, powders, or vitreous granular materials in order to obtain a decoration having pre- established shape and thickness. Subsequently, it is provided detaching the decoration from the supporting sheet and inserting it into a ceramic mould in order to press it with the powders so as to obtain a formed tile.

With this method, any dysfunction due to the presence of the supporting sheet during the pressing, drying or firing, is prevented but it is not possible to produce decorations constituted by decorating elements separated from each other, because, being missing the supporting sheet, it would result practically impossible to accurately arrange the decorating elements into the moulding cavities in a repetitive manner. In WO94/06728 the application of decalcomanias to supports without the need to dampen them in advance is described, instead inserting them into the pressing mould. Such decalcomanias are made of a mixture of ceramic glaze and cellulose mixed together and therefore, during the firing of the tiles in kiln, when the cellulose burns, gaseous residues or ashes are released, damaging the decorating glaze. For this reason, such decalcomanias were not particularly appreciated.

The state of art further comprises the Italian patent application O96A000166 that shows a machine for introducing decalcomanias into a mould for pressing powders so as to obtain ceramic tiles in order to form ceramic supports incorporating such decalcomanias. In that machine a pair of manipulators is provided placed in the front side of the press and each comprising a catching member that extracts by vacuum the decalcomanias, singularly, from a respective store, where they are stacked, in order to transfer them to a corresponding cavity of the press. Because each decalcomania is coupled to a supporting sheet, for each manipulator is provided a pincer catching member that grasps the supporting sheet, separates the supporting sheet from the decalcomania and delivers the supporting sheet to a collecting container. After the decalcomania has been separated from the sheet, the manipulator transfers it into the cavity of the mould. An object of the present invention is to improve the systems and/or the decorations known in order to decorate ceramic manufactures.

A further object of the present invention is to improve the known systems for application of the decalcomanias to already formed ceramic supports.

A further object of the invention is to produce a decalcomania type decoration, that can be applied to the supports without being dampened in advance, but does not present the drawback shown by the known decalcomanias with cellulose-based support, In a first aspect of the invention, a machine is provided for decorating supports, comprising applicator means arranged in order to apply decorating sheet means to said supports that are delivered by a transfer line, wherein said applicator means cooperates with reference means on said line suitable to maintain each support in a decorating station while said applicator means presses on it one of said decorating sheet means in order to cause it to adhere thereto. Said applicator means preferably has a profile of the working surface that is conjugated with respect to the support on which said decorating means must be applied.

When said applicator means is put in touch with said support, the working surface of said application means and the profiled surface of said support fit each on the other causing a satisfying adhesion of the decorating sheet means, comprised between them, to said support.

In further preferred versions, it is provided that said applicator means is associated to rotating or linear actuating means. The linear^' actuating means can operate, with respect to the ceramic supports, along a oblique direction, or along a direction parallel or orthogonal to the ceramic supports. Furthermore, the applying means can operate in only one side of the supports, or on parallel opposite sides in the case of manufactures having a substantially plane development. Preferably, said applying means is made of a material chosen from a group comprising foam rubber, sponge, silicone. In a second aspect of the invention, a method is provided for decorating already formed ceramic supports, comprising applying decorating sheet means to an already formed ceramic support, characterized in that, said associating is carried out before sending to firing said support associated to said decorating sheet means..

That allows to dramatically reduce the production costs of ceramic supports decorated with decorating sheet means. In fact, the pressing of the powders can be carried out in a traditional way and the final products are obtained with only one firing. Consequently, the decorations of said supports are much more resistant than the decorations applied with "twice fired" decalcomania.

In a third aspect of the invention, a method is provided for decorating supports applying decorating sheet means on them, comprising advancing the supports along a direction and applying onto each support one said decorating sheet means through motorized applying means.

In a preferred version of said method, it is provided that said applying comprises pressing on each support at least a portion of said decorating sheet means.

In this way, the application of decorating sheet means can be carried out very quickly and without the use of manpower. In a fourth aspect of the invention, it is provided a ceramic frit for the use in decorating sheet means, characterized in that, said frit comprises at least one oxide selected in a group comprising BaO and PbO and said at least one oxide is contained in a substantial proportion in said frit. Due to this aspect of the invention, it is possible to produce decorating sheet means that can be applied to an already formed, but not yet fired, ceramic support, that does not result possible with the decalcomanias according to the state of art.

Preferably, the frit comprises a percentage of BaO greater than 3%.

Advantageously, said percentage of BaO is within 15% and 20%, and in particular is very close to 18%. Preferably, furthermore, the frit comprises a percentage of PbO greater than 1%.

Advantageously, said percentage of PbO is within 19% and 22%,_. and in particular is very close to 20%.

In an advantageous version, the frit has the following composition:

A1203 9 - 12

B203 2 - 4

Siθ2 36 - 45

CaO + MgO 2 - 4

PbO 19 - 22

ZnO 4 - 6

BaO 15 - 20

Alkali 2 - 4

Li2θ 0 - 3

In another advantageous version, the frit has the following composition:

A1203 10

B203 4

Siθ2 38

CaO + MgO 3

PbO 20

ZnO 5

BaO 18

Alkali 1.5

L12O 0.5

The frit according to the invention can be used in combination with the usual ceramic glaze employed for the production of the traditional decalcomanias.

For the preparation of the decorating sheet means according to the invention, it is possible to proceed according to the steps here indicated: la) silk-screen printing on a sheet of glossy paper of glazes of one or more colours in order to form images;

2a) subsequently applying a layer of frit, in solution with a silk-screen vehicle, or in powder; 3a) finally applying a layer of collodion, or glue in general, in order to mutually fix the colours to the frit; In order to apply the decorating sheet means on a ceramic support formed but not yet fired, it is possible to work manually, or using the machine according to one of the aspects of the invention.

For the manual application, it is possible to proceed according to the steps here indicated: lb) dry- or damp-separating the decorating sheet means from the sheet of glossy paper;

2b) humidifying the ceramic support in order to prepare it to the application of the decorating sheet means thereon; 3b) spatulating the decorating sheet means on the ceramic support in order to remove air bubbles and cause the decorating sheet means to completely adhere to it; 4b) possibly drying and firing of the support, preferably in a single step;

Various kinds of ceramic supports can be decorated with the decorating sheet means forming the object of the present invention, they can comprise, indicatively, ceramic tiles, ceramic plates, ceramic steps in only one piece or assembled. In a fifth aspect of the invention, decorating sheet means is provided, comprising particles of colouring material, fixing means in order to mutually aggregate said particles and supporting means for said particles, characterized in that said fixing means has dimensions and consistency such as to form also said supporting means.

In a particularly advantageous version, said fixing means and said supporting means comprise a collodion-based plastic substance. .

In this way, causing the fixing means of the colouring particles to perform also the function of supporting means for the particles, no paper support has to be used. In this way, single sheet decorating means of ceramic manufactures is obtained. That produces the advantage that it is possible to apply the single sheet decorating means without it must be previously separated from a protection and supporting sheet, for example by immersion in water, with remarkable simplification of the application cycle of the decalcomanias to the supports to be decorated.

In a particularly advantageous version, said particles of colouring material are distributed in regions isolate from each other. A portion of said fixing means and said supporting means extends between said isolate regions. A further portion of said fixing means and said supporting means extends externally to said isolate regions.

In a further advantageous version, a layer of glass grit is arranged above said colouring particles.

In a sixth aspect of the invention, a method is provided comprising:

- applying at least a layer of colouring particles onto a working plane;

- further applying, on said at least one layer, fixing means in order to mutually fix said colouring particles, characterized in that:

- said working plane is made of a material on which said particles and said fixing means adhere in a peelable manner; and

- after said further applying it is provided removing in peelable manner from said working plane the combination of said fixing means and said colouring particles. Therefore, the decorating sheet means no more must be supplied in association with a paper support and, mainly, it is no more necessary to detach the decorating sheet means from the support in order to apply them to the object to be decorated. On the other end, the risks connected to the use of the cellulose as supporting means are prevented.

In fact, when decorating ceramic tiles, the use of the collodion for said fixing means is well borne during firing, even when it is used in amounts much greater than normally used in the conventional decalcomanias. In a particularly advantageous version, before said further advancing, it is provided dispensing, onto said colouring particles, particles of glass grit.

After said further applying and before said removing, it is advantageous providing that said fixing means take such a consistency that they can act as supporting means. It is furthermore advantageous applying the combination of said fixing means and said at least one layer of colouring particles onto a ceramic tile, with said fixing means turned towards said ceramic tile.

In a seventh aspect of the invention, it is provided a method for manufacturing decorated ceramic tiles, comprising pressing together in a ceramic mould decorating means and ceramic powders and extracting from said mould formed tiles, comprising said decorating means, said decorating means being initially coupled to sheet supporting means, characterized in that said sheet supporting means is such to detach itself from said decorating means when said formed tiles are ejected from said mould.

In this manner, the sheet supporting means does not advance together with the formed tiles towards the next steps of drying and firing, but is removed from the tiles downstream the pressing station.

The sheet supporting means is removed from the top of said tiles through catching and transferring means. The catching and transferring means comprises sucking means suitable to pick up said sheet supporting means from said tiles and to release it in a storing position. Said sucking means can comprise a sucking hose mounted on a respective arm, moving between a catching position on the formed tiles and an unloading position, in a recovering and storing region, of the sheet means.

That allows, furthermore, to reduce the consumption of sheet supporting means as it can successively be reused. In order to assure that the sheet supporting means detaches itself at the ejection of the formed tiles from the mould cavities, it is chosen such to result flexible but also dimensionally stable, i.e. trending to maintain constant its geometric development and its surface extension during and after the pressing of the powders in the mould. On the contrary, the pressed tiles - as known - laterally expands once released from the mould wherein they were pressed, until they take dimensions remarkable greater than the dimensions of the generating cavity. In this way, as an effect of the different behaviour of the decorating means, that follows the deformations of the ceramic support to which it has been associated during pressing, and of the sheet supporting means, that instead tendentially maintain the same shape and dimensions than before the pressing, at the interface between the sheet supporting means and the decorating means there is a shear stress that causes the detachment of the sheet supporting means from the decorating means.

In practice it happens that, while the decorating means follows the expansion of the formed tile, being on integral part thereof, the sheet supporting means tends instead to maintain its initial extension, so leaving the respective formed tiles.

After the removal of said sheet supporting means, the tiles incorporating the decorating means are advanced alone towards the drying and the firing, without said sheet supporting means .

In a eighth aspect of the invention, a machine is provided in order to manufacture decorated ceramic tiles, comprising pressing means in order to press together in a ceramic mould decorating means and ceramic powders and to extract from said mould formed tiles incorporating said decorating means, characterized in that it further comprise evacuating means in order to move, downstream said pressing means, from said formed tiles, sheet supporting means initially associated to said decorating means.

The evacuating means can comprise catching and transferring means. The catching and transferring means can comprise sucking means suitable to pick up said sheet supporting means from said tiles and to release it in a storing position. The sucking means can comprise a sucking hose supported to a moving arm.

In a ninth aspect of the invention, decorating sheet means is provided, comprising sheet supporting means to which decorating means is associated, characterized in that said sheet supporting means is chosen so that it can detach itself from said decorating means when formed tiles, to which this last is associated, are extracted from a forming mould. The decorating means is adhesively coupled to said sheet supporting means in a substantially less strong manner than the same decorating means can be coupled to ceramic powders on which it is pressed.

In a particularly advantageous version, the decorating means can be coated, in its portion arranged for the contact with the powders of the tile to be formed, with gripping material to said powders, consistent with the above mentioned powders. Said gripping material being selectable from a group comprising: said powders, ceramic glazes, clay, dyes. That allows to improve the gripping of the decorating means to the powders, still leaving unchanged the multiplicity of possible obtainable decorations.

The invention can be better understood with reference to the enclosed drawings, that illustrate some not restrictive embodiment examples thereof, wherein:

Figure 1 is an elevation view of a machine for applying decorating sheet means to ceramic supports; Figure 2 is a side view from left of Figure 1; Figure 3 shows, in a top view, reference means for a ceramic support;

Figure 4 is a cross section of the machine of Figure 1 wherein the decorating sheet means is applied to the edge of steps of ceramic material by .means of applying rollers; Figure 5 is an enlarged view of the applying rollers of Figure 4; Figure 6 is a view as Figure 5, but relative to a variation of the arrangement of the applying rollers;

Figure 7 is a side view of a portion of the machine of Figure 1, but relative to a variation wherein the decorating sheet means is applied to a edge of step of ceramic material, arranged longitudinally with respect to an advancing direction;

Figure 8 is a top view of Figure 7;

Figure 9 is the sketched section IX-IX of Figure 8; Figure 10 is a vertical section of a variation of applying means of decorating sheet means;

Figure 11 is a side enlarged view of separating means in order to separate decorating sheet means from relative supporting means, at a starting working position;

Figure 12 is a view as Figure 11, but showing the separating means in an end position wherein the supporting means is completely separated from the decorating sheet means; Figure 13 is a top view of a machine for applying decorating sheet means to ceramic supports in a further version; Figure 14 is a section along the plane XIV-XIV of Figure 13; Figure 15 is the section XV-XV of Figure 13, showing a cabin for the application of glue in water solution to the ceramic supports;

Figure 16 is the section XVI-XV of Figure 13, showing applying means of decorating sheet means provided with an applying head,;

Figure 17 is a partial and enlarged view of the applying head of Figure 16, wherein the applying head is shown in combination with a ceramic support lifted from the advancing line of the ceramic supports by lifting means; Figure 18 is a section as Figure 17, wherein the applying head of decorating sheet means is shown in contact with a ceramic support in the act of applying a decorating sheet means; Figure 19 is a section along the plane XIX-XIX of Figure 13, showing rotating applying -means of decorating sheet means; Figure 20 is a section along the plane XX-XX of Figure 13; Figure 21 is a section along the plane XXI-XXI of Figure 20; Figure 22 and Figure 23 are side view of applying linear means, respectively oblique and horizontal, of decorating sheet means;

Figure 24 is a top view of a station of the machine according to the invention, comprising horizontal bilateral applying means of decorating sheet means;

Figure 25 is the section along the plane XXV-XXV of Figure 24; Figure 26 is an elevation view of a station of the machine - according to the invention, comprising linear vertical applying means of decorating sheet means;

Figure 27 is a section along the plane XXVII-XXVII of Figure 24;

Figure 28 is an enlarged view of a variation of the linear vertical applying means of Figure 26;

Figure 29 is a section of a decorating sheet means according to the invention, during the step in which collodion is applied on regions of ceramic glaze already silk-screen printed on a working plane;

Figure 30 is a section as Figure 29, but showing the collodion that, after the application, passes through the particles of ceramic glaze until it settles onto the working plane; Figure 31 is a section of a decorating sheet means according to the invention ready^' for the use on a ceramic support; Figure 32 is a strongly enlarged view of a cavity of ceramic mould during the pressing; ^•

Figure 33 is a section as Figure '32, but relative to a edge region of the cavity at the expulsion step of the formed tile. As shown in Figures 1 and 2, a machine 1 comprises applying means 2 having an applying head 4 mounted at one end of a supporting shaft 6 coupled, so as to be arrangeable in height through a sleeve 8, to a trolley 10 sliding on a drive beam 12. The drive beam 12 is fixed to a frame constituted by two consecutive portal structures 13 arranged around a conveying line 14, whereon a storage device 3 (compenser) for ceramic supports is inserted. The drive beam 12 is arranged parallel to, and above, the conveying line 14 onto which ceramic supports 16 are caused to advance along an advancing direction denoted by F.

The ceramic supports 16 can comprise a ceramic tile, a ceramic plate, a listel or "fillet" or a step of ceramic material integral or modular.

The steps of ceramic material can be divided into a tread edge, substantially constituted by a common tile, associable to a riser comprising a profiled edge, usually called "little torus".

Along the conveying line 14 an application station 20 is arranged in which through the applying head 4 a decalcomania 18 is applied on every ceramic support 16. The application station 20 is provided with reference and control means 19 that allows to stop the ceramic support 16 in the application station 20 and to prearrange it to the action of the applying head 4.

The application of a decalcomania 18 is carried out iaying onto the ceramic support 16, standing in the application station 20, the applying head 4 to which the decalcomania was adherent as a result of the vacuum produced at the surface 21 of interface with the decalcomania 18 by depressurizing means 72. For this purpose the interface surface 21 must be gas- permeable, e.g. provided with micro-holes 49 (see Figure 10). Preferably, at the ' moment of the application of the decalcomania 18 in the application station 20, a slight overpressure can be applied through the interface surface 21. In fact the decalcomania 18 would trend to stay adherent to the applying head 4, because - in a possible version - at the moment of the application it is still dampened as it has been subjected to a humidification treatment in a humidification tunnel 22.

The humidification tunnel 22 is arranged between a store 24 of decalcomanias 18 each anchored to a support sheet 17 and stacked on each other, and the application station 20, so as to result overhanging the conveying line 14. The humidification tunnel 22 is crossed by the applying head 4, that carries a decalcomania 18 still provided with the supporting sheet 17 associated thereto. In a first portion 26 of the humidification tunnel 22 a plurality of nozzles 28 is provided that spray from the bottom the supporting sheet 17 with hot water so as to prepare it to detach from the decalcomania 18. In a second portion 27 of the humidification tunnel 22 blowing means 29 is provided in order to blow hot air, or steam, towards the supporting sheet 17 and activate its separation from the decalcomania 18. The water and the possible steam (condensed) are collected into an underlying tank 25, in order to be possibly recovered. In the second portion 27 roller sucking means 30 is provided that licks from the bottom the sheet 17 and separates it definitively from the decalcomania 18. The roller sucking means 30 can also operate in the absence of the blowing means 29. Besides the roller sucking means 30 a diverting roller 31 is arranged in order to divert downward the sheet 17, already detached from the decalcomania 18, and direct it towards clearing means 32, for example tape means .

In a further version, it is possible to use decalcomanias deprived of the sheet 17, so that they do not need humidification. In such version the humidification tunnel 22 results unnecessary and therefore it is removed. Besides the application station 20, astride the conveying line 14 a pressing roller 30 is provided that, as the tile resume to move along the conveying line 14, carries out a slight pressure on the decalcomania 18 so as to make more secure its application to the ceramic support 16.

During the working, while the conveying line 14 "transfers a support 16 from the compensation device 3 to the application station 20, the applying head 4 draws from the store 24 a decalcomania 18 with the supporting sheet 17 associated thereto, transfers it through the humidification tunnel 22 where this loses the supporting sheet 17 and at last transfers the decalcomania 18 alone on the ceramic support 16 waiting in the application station 20.

In order to avoid that the decalcomanias 18 in the store 24 can adhere to each other and to make easier the detaching of the decalcomanias from the supporting sheet 17, advantageously the supporting sheet 17 is siliconed or polythened on both sides.

As shown in Figure 3, the application station 20 has reference and locking means for the ceramic support 16 constituted by angle bars 34 arranged at opposites corners of the ceramic support 16.

As shown in Figures 4 and 5, the machine 1 can be provided with auxiliary applying means 38 in order to apply the decalcomania 18 onto a profiled edge region 40 of the ceramic support 16, as in the case of steps.

The auxiliary applying means 38 comprises a set of rollers 42a, 42b, 42c arranged angularly spaced from each other so as to angularly cover the whole profile of the edge region 40. The rollers 42a, 42b, 42c are fixed to a support 44 so as to result free to rotate around the respective longitudinal axes, that lay on transversal planes with respect to the profile of the edge region 40. Furthermore the rollers 42a, 42b, 42c are at a certain distance apart from each other, so as to apply a progressive action onto the edge region 40 to be coated. The support 44 is slidably coupled to a transversal guide 46, fixed to side walls 48, that results transversally arranged with respect to the line 14 and above it.

When the support 44 is caused to slide along the transversal guide 46, the ceramic support 16 is already provided with the decalcomania 18 in its plane portion and is kept in position by auxiliary reference means 50, that can be also incorporated in the reference means 34; during the advancing of the support 44 the roller 42a, the nearest one to the edge region 40, i.e. the first one of the rollers 42 that engages the ceramic support, that operates close the section 40 nearer to the plane region of the ceramic support 16, i.e. the region where the decalcomania 18 is already applied. Subsequently, also the roller 42b begins to engage the ceramic support 16 and operates on the region 40b immediately adjacent to the region 40a where the decalcomania 18 has been just applied by the previous roller 42a. At last also the roller 42c intervenes providing to complete the application of the decalcomania 18 in a subsequent region 40c of the ceramic support 16. .

Practically, the rollers 42a, 42b, 42c operates gradually applying the decalcomania to the consecutive sections 40a, 40b, 40c of the edge region 40. The rollers 42a, 42b, 42c are constituted by soft yielding material so as to conform to the profile of the edge region 40, whatever it may be, without damaging the decalcomania 18.

Alternatively, as represented .in Figure 6, the decalcomania 18 can be applied to the edge region 40 with other auxiliary applying means 38a comprising a profiled roller 52, supported free to rotate to a support 44a, in which roller a groove 54 is obtained having shape corresponding ^■ to the shape of the profile of the edge region- 40.

Obviously, also the auxiliary applying means 38 can be constituted by profiled rollers, analogous to the profiled roller 52, 54.

With reference to Figures 7, 8, 9 a further variation of auxiliary applying means 38b is shown, for example provided with profiled roller 52, 54, pivotally coupled around a vertical axis V to fixed supporting means 55, arranged next to a section of a belt conveying line 56 that advances the ceramic supports 16 along a direction FI that can coincide with the direction F.

In combination with the auxiliary applying means 38b a conveyor belt 58 is provided that is interposed between the belts 56 of the line and is suitable to receive the ceramic supports 16 that it advance through protruding elements 59, that it is provided with, acting as pushing elements for the supports 16 through the auxiliary applying means 38b. At the opposite side of the line 56 with respect to the side occupied by the auxiliary applying means 38b control means 60 is provided suitable to prevent lateral movement of the support 16 engaged on the auxiliary applying means 38b but such as not to avoid, on the contrary to facilitate, the advancing of the ceramic support 16 along the conveying line 56. The control means 60 comprises a tape, or a belt, 62 wound around rollers 64 but can be also constituted by a set of rollers, or idle wheels supported to the side of the conveying line 56.

With reference to Figure 10, a variation of the applying head 4 is shown wherein the interface surface with the decalcomania 18 is constituted by a set of cavities 65, or protrusions 66 corresponding to protrusions 65a, or relative cavities 66a with which the ceramic support 16 is provided. That allows to apply the decalcomania 18 also to ceramic supports wherein the surface to be decorated is not flat, such as, for example, the so called "structured" tiles.

As shown by the dotted line, the interface surface of the applying head 4 extends towards a rounded edge 61 of the ceramic support 16 extending beyond it so as to show a strip 68 ready for the subsequent action of the auxiliary applying means 38, 38a, 38b according to circumstances. With reference to Figures 11 and 12, dry separating means 90 is shown suitable to separate a decalcomania 18 from the relative supporting sheet 17, without the decalcomania 18 must to be subjected to humidification treatments. The dry separating means 90 comprises suction cup means 91 suitable to remove a strip of the supporting sheet 17 from the decalcomania 18 and blade means 92 suitable to be moved between the supporting sheet 17 and the decalcomania 18 causing its complete detachment from the supporting sheet 17. A decalcomania 18 is drawn by the applying head 4 and stays fixed thereto by means of the vacuum pressure created by a plurality of suction cups 124. The sucking means 91, acting at one end of the decalcomania 18 separates from this a first section of the supporting sheet 17, creating an insertion point A for the blade means 92. The blade means 92 is caused to slide passing in contact with the surfaces of mutual adhesion of the decalcomania 18 and the supporting sheet 17 so as to cause their complete detachment. After the detachment operated by the blade means 92, the decalcomania 18 remains fixed to the applying head 4 ready to be placed on a ceramic support 16, . while the supporting sheet 17 is led by the sucking means 91 over a collecting container, not represented, into which it is left to fall.

In Figures 13, 14, 15 a cabin 100 is shown, inside which a ceramic support 16 is caused to pass, lying on belts 105 of a conveying line 14 having motorized pulleys 100. The decalcomanias 18, that are applied with the machine according to the present invention, result directly applicable to the ceramic support 16, a previous separation from a further support, usually a paper support, being not necessary; it is necessary, nevertheless, to treat the surface of the ceramic support 16 with gluing material. A glue in water solution 109 is contained in a tank 111 and is withdrawn from the tank 111 by a pump 108 that sends it to a nozzle 106 that provides to spray the upper surface 16b of the ceramic support 16; in case the ceramic support 16 is a special piece, having a particular shape, or a profiled portion of the edge 40, one or more further nozzles 107 are provided, that provide to spray with glue the points inaccessible to the nozzle 106. As shown in Figures 16, 17 and 18, a first working station 102a of the machine according to the invention comprises downstream the cabin 100 applying means 102 having an applying head 4 mounted at one end of a supporting shaft 6 coupled, so as- to be arrangeable in height, through a sleeve 8 to a trolley 10 sliding on a guide beam 12a. The guide beam 12a is arranged perpendicular to, and above, the conveying line 14 on which ceramic supports 16 are caused to advance along a direction denoted with the arrow Y.

A container 119 is provided, wherein the decalcomanias 18 are stacked, placed to the side of the conveying line 14 and below the guide beam 12, so as the applying head 4 can withdraw from it the decalcomanias 18 one at a time and the apply them to the ceramic support 16. On one of the sides of the container 119 there is placed a photocell 122 that, by emitting a signal that control a rod 122, slidably coupled to a motor reducer 121, the rod 122 being disposed on the lower moving face 142 of the container 119, keeps constant the height of the withdrawal plane of the decalcomanias 18 by the applying head 4.

In the first applying station 102a, a decalcomania 18 is applied on each ceramic support 16 through the applying head 4. The first applying station 102a is provided with plate lifting means 123 that raises the ceramic support 16 preparing it to the action of the applying head 4.

The trolley 10 carries the applying head 4 over the container 119 from which the applying head 4 withdraws a decalcomania 18. The decalcomania 18 at the top of the stack of decalcomanias is caused to adhere to the applying head 4 under the effect of a vacuum pressure created by suction cups 124. Once the decalcomania 18 has been withdrawn, the trolley 10 carries the applying head over the ceramic support 16, previously lifted by the plate lifting means 123, that moved upwards along the direction of the arrow Y' .

The plane containing the decalcomania 18 and the plane containing the upper surface 16b of the ceramic support 16 are not perfectly parallel to each other, that in order to allow a complete and optimal discharge of air during the application of the decalcomania 18 onto the ceramic support 16; that is obtained connecting the decorating head 4 and a plate 126, to which the suction cups 124 are attached, through a hinge 127, placed at one of the ends of the plate 126, and through a spring 128, placed at the other end of the plate 126, the spring 128 having elastic properties and geometry such to maintain, in an equilibrium condition, the plane comprising the decalcomania 18 and the plane comprising the upper face 16b of the ceramic support 16 not parallel to each other. When the applying head 4 reached the application position in combination with the waiting ceramic support 16, the supporting shaft 6 slides inside the sleeve 8 moving vertically downwards, along the direction of the arrow Y''; the decalcomania 18 is then in contact with the ceramic support 16, previously prepared with adhesive, to which it remain attached.

Preferably, during the application of the decalcomania 18 a slight pressure can be carried out through the interface surface; such operation is simplified placing, at the interface surface, a cushion 125 of soft and easy compressible material, suitable to produce a delicate, but uniform pressure on the surface of the decalcomania 18, promoting its adhesion to the ceramic support 16.

Advantageously, the cushion 125 of soft and easy compressible material can be made of foam-rubber, sponge o smooth silicone, Advantageously, the suction cups 124 can be connected to a Venturi tube capable to create in a first time a vacuum pressure that maintain the decalcomania 18 in contact with the suction cups 124, subsequently, when the decalcomanias were positioned onto the ceramic support 16, the Venturi tube gives off a jet of air that, hitting the decalcomanias 18, improves their adhesion to the ceramic support 16.

Advantageously, downstream the applying means 102 of the first station 102a, compressing means 160 can be arranged, suitable to assure the adhesion of the decalcomanias 18 to the ceramic support 4. Particularly, the compressing means 160 must result flexible in order not to obstruct the advance of the ceramic support 16 and can result constituted by rubber spatules 162, of the type used in order to silk-screen ceramic tiles, or by brushes, o by rollers of smooth silicone or, eventually, by a combination of these.

In Figures 19, 20, 21, in a second applying station 103, a ceramic support 16 is shown, provided with an upper smooth surface 16b and a profiled portion 40, laying on belts 105, belonging to the conveying line 14; said ceramic support 16 is caused to pass through a casing 129 containing applying means provided with rotating actuation means 134 of decalcomanias 18, said rotating actuation means comprising pressing means 132, fixed to connecting rod means 131, and a cylinder 130 slidably coupled to a piston 133.

The ceramic support 16, onto which a decalcomania 18 has been previously placed, perfectly adhering to the upper surface 16b of the ceramic support, but with exclusion of the profiled portion 40, is caused to advance on the conveying line 14; when it arrives in the casing 129 a photocell 135 control the stop of the belts 105 and the lifting of the ceramic support 16, according to the direction of the arrow P, with respect to the conveying line 14.

The piston 133, to whose free end the connecting rod means 131 is pivotally coupled, constituted by a rod 166 and a bridge 164 suitable to support the pad 132, is caused to advance inside the cylinder 130; because the bridge 164 belonging to the connecting rod means 131 is connected through a pin 135, passing through two holes 136 therein obtained, to the casing 129, a rotation of the connecting rod means 121 and the pad means 132, to it fixed, around the point G, according to the direction of the arrow R corresponds to the advance of the piston along the direction of the arrow N; such rotation causes the adhesion of the decalcomania 18 to the profiled portion 40 of the ceramic support 16, obtained by padding. The presence of the bridge 164 on the connecting rod means 131 allows the substitution of the pad 132 and therefore the possibility to work lots of supports having shapes different from each other, only substituting the pad 132. In Figure 22 there are shown a ceramic support 16, whereon a decalcomania 18 has been previously settled, that perfectly adheres to the upper surface 16b of the ceramic support with exclusion of the profiled portion 40, and applying means of decalcomanias 18 provided with linear actuating means 136, said linear actuating means 136 being moving along an oblique direction with respect to the surface 16b of the ceramic support 16.

The linear actuating means 136 comprises further pad means 138, fixed to a stem 139 slidably coupled to a seat 140, having the same shape of the cavity of the profiled portion 40 of the ceramic support 16 to which the decalcomania 18 has to be caused to adhere. The stem 139 is advanced inside the seat 140 along the direction of the arrow S, so making the decalcomania 18 to perfectly adhere to the support 16. In Figure 23 applying means is shown provided with linear actuating means 137, said linear actuating means 137 being movable along a horizontal direction with respect to the surface 16b of the ceramic support 16.

The linear actuating means 137 is substantially analogous to those of Figure 20 with the difference that, instead of the further pad means 138 there are other pad means 141 obtained from a brush, whose bristles 143, made of very compression- resistant material, were cut so as to exactly take the shape of the profiled portion 40 of the ceramic support 16. In Figure 24, 25 and 27 a working station 103a is shown wherein applying means of decalcomanias 18 is operating, provided with linear actuating means 144, that operates by moving along a horizontal direction and involving two opposite sides of a same ceramic support 16; for this reason ceramic supports 16 of type of special pieces are preferably treated inside the working station 103a, and more in particular, special pieces having a symmetrical plane perpendicular to the upper surface 16b of the ceramic support and parallel to the advancing direction of the ceramic supports 16 onto the conveying line 14; therefore the special pieces just described have two profiled portions 40 at opposite parallel sides. The bilateral linear applying means 144 is accommodated inside a supporting frame 145 and comprises a piston 133 slidably coupled to a cylinder 130 and a pair of rods 146 to each of which a pad means 141 is fixed. Each rod 146 has an end firmly fixed to one of the pads 141 and the other end free to slide inside a hole 149 obtained in the supporting frame 150 of the other pad 141, furthermore a rack element 147 is fixed in the central portion of each rod 146 suitable to engage with a pinion 148.

When a ceramic support 16, on which a decalcomania 18 has been applied, adhering to the surface portion 16b, with exception of the profiled portion of the support 16, arrives into the working station 103, the sliding of the piston 133, fixed to one of the rods 146, inside the^' cylinder 130, causes the pad means 141 thereto fixed to carry the decalcomania 18 to adhere to the profiled portion 40 of the ceramic support 16. Due to the presence of the pinion 148 the movement of the first rod 146 is inverted and transmitted to the second of the • rods 146 producing an analogous pressure on the other profiled end 40 of the ceramic support 16.

In this case the adhesion by pressure of a ceramic support 16 takes place, while the support 16 is laying on the belts 105 of the conveying line 14; then the presence of lifting means is not necessary that moves and firmly holds the piece, because the stresses that are transmitted to the piece, have the same strength, the same action line B and opposite directions .

In Figure 26 a ceramic support 16 of special piece type is shown, whereon a decalcomania 18 has been applied, that adheres to the ceramic support only in a transversal section 151, enough to hold the decalcomania 18 well adherent and in its correct position for the following application steps. The ceramic support 16 moves on the conveying line 14 until it reaches applying means of decalcomanias 18 provided with vertical actuating means 155 comprising mechanical catch 152, a supporting means 153 and a pad means 141; when the ceramic support 16 reaches the mechanical catch 152 that can be operated along a vertical direction by an operating cylinder 169 between a lower position and a raised operating position, it is lifted by a supporting means 153 and brought, through the action of driving means 168, up to a pad means 141, having the same shape of the ceramic support 16, whereon the decalcomania 18 is caused to adhere in every portion thereof to the ceramic support 16.

In Figure 28 vertical operating means 158 is shown analogous to those shown in Figure 26 wherein the pad means 141 is made of silicone and is provided with a duct 157, through which, by means of an adaptor 156, compressed air is caused to pass into the pad means 141 and spreads onto the surface of the ceramic support 16, producing a substantially uniform air pressure. In this way a mechanical padding produced by the pad means and a pneumatic padding caused by the compressed air are combined together.

Therefore, a complete adhesion of the decalcomania 18 is carried out also on ceramic supports 16 that have a complex profile and in presence of possible deformations of the ceramic support 16 with respect to the shape of the pad means 141 of silicone material. Furthermore the extraction of the ceramic support 16 from the pad means 141 becomes possible also when the ceramic support 16 has profiles with slight undercuts .

Furthermore the permanence of the decalcomania 18 in its correct position is assured, preventing its sliding inside the pad means 141, during the descent of the ceramic support 16, in the extraction step.

In Figure 29 decorating sheet means is shown wherein a set of regions of ceramic glaze 202 are distributed on a working plane 204, for example by means of silk-screen process, and a collodion layer 206 is applied on them.

The collodion layer 206 is initially arranged so as to coat, as shown with the marker 206a, the glaze regions 202 and, as shown with the marker 206b, regions 204a of the working plane 204 comprised between glaze regions 202 adjacent and- further portions 204b external to the glaze regions .202a. On the regions of ceramic glaze 202 a layer of particles 208 of glass grit can be distributed.

As shown in Figure 30, as the collodion 206 is applied in liquid form, it penetrates through the gaps kept between the grit particles 208 and the glaze particles 202 of each region and falls by gravity through them and fixes them until it settles on the working plane 204.

In this manner, the collodion 206 has carried out two functions simultaneously, i.e. to mutually fix the particles of each glaze layer 202 and grit 208, binding them, and to act as supporting means for the decorating means, without using an external paper support which has to be removed when the decorating means has to be used. However, in order to prevent that, during the stacking of a plurality of decorating sheet means, one on the other, undesired adhesions of regions of decorating sheet means with corresponding regions of another overhanging, or underlying, decorating sheet means can take place, it is advantageous to insert between adjacent decorating means a separating sheet, that has been siliconed or polythened on both the faces, or in any way treated on both the faces with an anti-adhesive substance.

In Figure 31 is shown the decalcomania constituted by the layers of glaze particles 202, of glass grit 208 and collodion 206, after it has been removed in a peelable manner from the working plane 204, to which the collodion and the layers 202 do not permanently adhere.

The working plane 204 can be made of silicone paper, or silicone cardboard or any other material with no adhesive- affinity with the collodion 206, so that, as the collodion has been stabilized and dried, it is possible to easy detach the collodion from the working plane 204 with the glaze layers 202 and possible grit 208 to it associated.

Experimentally, it has been realized that, with an overall thickness near to some tenths of millimetre, e.g. 0.4 mm, the decalcomania has an acceptable consistency and can be easy applied on a ceramic support.

In order to proceed to the application of the decalcomania on a ceramic support, it is advisable to spread an adhesive layer on this before to put on it the decalcomania. Nevertheless, it has been observed that the application of the decalcomania is possible also without the adhesive layer, preferably when the application is performed on a ceramic support at a temperature slightly higher than the room temperature, that happens - for example - when the supports get out of the dryer.

The application on a ceramic support is carried out leaning the collodion 206 in contact with the ceramic surface to be decorated and keeping the glass grit particles 208 separated from the ceramic surface by the interposition of the layer of glaze particles 202.

An important advantage of the sheet decorating element lies in the possibility of removing in the ceramic plants the glazing lines that involve the onerous treatment of the ceramic glazes and the consequent sludge.

That implies the possibility of obtaining the decorations for ceramic supports in a more controllable way and with less risks for the environment pollution.

With reference to Figure 32, in a ceramic mould 301 comprising a base 32 and a punch 303, powders 305 of a ceramic tile to be produced are contained inside a cavity 304. The punch 303 is pressed again the base 302 along a direction W until a compaction of the powders 305 to the desired degree is obtained. A decalcomania 18 is interposed between the punch 303 and the powders 305 and is constituted by inserts 307, 308 coupled in adhesive way to a sheet 318, e.g. of silicone paper.

The inserts 307, 308 can be produced through silk-screening of glazes, or colouring materials, or clay, or their mixtures preferably containing in any way a low amount of glass, and directly placed on the sheet 318.

As shown in Figure 33, when the powders 305 have been pressed to a sufficient degree in order to produce a formed tile 16 comprising the inserts 307, 308, the base 302 and a peripheral mould frame 311 initially bounding the cavity 304 are brought to the same level, so that the base 302 can eject from the cavity 304 the tile 16 just formed and define with the frame 311 a sliding plane 312 whereon the tiles are discharged along the direction W' .

It is noted that, after the ejection from the cavity 304, the tile 16 is wider than the dimensions of the cavity 304 that generated it, and its external edge passes from the initial position in which it was aligned with the edge 318' of the sheet 318 to a position 16' more external. During the execution of such movement, because the dimension of the sheet 318 remains substantially constant, being the sheet 318 made of material dimensionally stable, the sheet 318 breaks away from the inserts 307, 308 and remain substantially floating on the formed tile 16, available to the action of a suction means, non represented, that withdraw the sheet 318 and store it into a suitable container.

The inserts 307, 308 can be externally provided, at their region turned again the powders 305 during pressing, with a layer 314 of gripping material, advantageously constituted by the same powder 305 that fills the cavity 304 in order to constitute the body of the tile 16, or anyway by powdery material having the same chemical and physical properties of the material constituting the tile.

The layer 314 can be, in particular, constituted by inert material, neutral or coloured and can be applied by gravity or by silk-screen process.

The decorations constituted by the supporting sheet 318, the inserts 307, 308 and the possible gripping layer 314 can be used according to the specifications contained in the international patent application PCT/IT97/00247 and possibly in the Italian patent application n. MO96A000166.

Claims

1. Machine for decorating supports (4), comprising applying means (2, 4, 38, 38a, 38b, 102, 134, 136, 137, 144, 155, 158) arranged in order to apply decorating sheet means (18) to said supports (16) that are carried by a conveying line (14, 56), wherein said applying means (2, 4, 38, 38a, 38b, 102, 134, 136, 137, 144, 155, 158) cooperates with reference means (34) on said line suitable to maintain each, support (16) in an applying station (102a, 103, 103a) while said applying means (102) presses on said support one of said decorating sheet means (18) in order to cause it to adhere thereto.

2. Machine according to claim 1, wherein said catching means comprises depressurizing means (72) arranged so as to vary the pressure at the interface between said applying means (2, 4) and said decalcomania (18) .

3. Machine according to any of the preceding^' claims, wherein said applying means (2, 4) comprises a plate-shaped body (4) vertically movable.

4. Machine according to claim 1, or 2, wherein said applying means comprises roller means (42a, 42b, 42c, 52) .

5. Machine according to any of the preceding claims, wherein said applying means (2, 4, 42a, 42b, 42c) is made of resilient material.

6. Machine according to any of the claims from 2 to 5, wherein said depressurizing means (2) communicates with micro- holes (49) in said applying means.

7. Machine according to any of the claims from 2 to 6, wherein said interface has a conjugated profile (54, 65, 66) with respect to the region (40a, 40b, 40c, 61, 65a, 66a) of said support (16) that must be decorated.

8. Machine according to claim 7, wherein said conjugated profile has variations (65, 66, 54) of the profile suitable to engage in corresponding discontinuities (65a, 66a, 61) of the surface of said support (16) that must be decorated.

9. Machine according to any of the preceding claims, and further comprising separating means (30, 31) arranged in order to separate a protective sheet (17) from said decorating sheet means .

10. Machine according to claim 9, wherein said separating means comprises detaching blade means that can be interposed between said decorating sheet means and said protective sheet,

11. Machine. according to any of the preceding claims wherein said applying means (2, 4, 102) are supported to sliding means (8, 10, 12) and are movable between an applying station (20, 102a) of said decalcomanias (18) and store means (24, 119).

12. Machine according to claim 11, wherein between said store means (24) and said applying station (20) humidifying means

(22, 26, 27, 28, 29) is interposed along the path of said applying means (2, 4) .

13. Machine according to claim 12, wherein said humidifying means comprises supplying means (28, 29) in order to humidify a decalcomania (18) aboard said applying means (2, 4) .

14. Machine according to any of the claims from 4 to 13, wherein said applying means (42a, 42b, 42c, 52) is supported to a moving equipment (44) sliding on guide means (46) transversally supported to said conveying line (14) .

15. Machine according to any of claims from 4 to 13, wherein said applying roller means (52) is laterally supported to said conveying^' line (56) .

16. Machine according to claim 15, wherein, in a section of said conveying line (56) , conveyor means (58) is inserted provided with pushing means (59) in order to advance said support (16) .

17. Machine according to any of the preceding claims, wherein said applying means (2, 4, 38, 38a, 38b) cooperates with control means (19, 60 ) .

18. Machine according to any of the preceding claims and further comprising stabilizing means (33) arranged in order to stabilize said decorating sheet means (18) after said decorating sheet means adhered to said support (14, 61)

19. Machine according to any of the preceding claims and further comprising container means (119) of said decorating sheet means.

20. Machine according to any of the preceding claims, wherein said applying means comprises suction cup means (124) .

21. Machine according to any of the preceding claims, wherein said applying means is selected from a group comprising spatules (162), brushes, rollers of soft silicone, mix of brushes and rollers.

22. Machine according to any of the preceding claims, wherein said applying means is coupled with rotating actuating means (134, 136, 137, 144, 155, 158) .

23. Machine according to any of the preceding claims, wherein said applying means is associated to linear actuating means (134, 136, 137, 144, 155, 158).

24. Machine according to claim 23, wherein said linear actuating means operates along an oblique direction with respect to said supports.

25. Machine according to any of the preceding claims, wherein said applying means (137) comprises a body (141) provided with bristles (143) that were cut so as to conjugate with the contour of the profiled edge portion (40) of said support (16).

26. Machine according to claim 25, wherein said control means (153) comprises actuating means (168), that lifts each support (16) carrying it to an interaction position with said pad means (141) .

27. Method for decorating already formed ceramic supports (16), comprising associating decorating sheet means (18) to an already formed ceramic support (16), characterized in that, said associating is carried out before sending to firing said support (16) associated to said decorating sheet means (18) .

28. Method for decorating supports (16) applying decorating sheet means (18) .thereto, comprising advancing said supports (16) along a direction (F, Y) and applying onto each said supports (16) one of said decorating sheet means (18) through motorized applying means (2, 4, 38, 38a, 38b, 102, 134, 136, 137, 144, 155, 158) .

29. Method according to claim 28, wherein said applying comprises applying at least a portion of said applying sheet means (18) to at least a portion of said support (16) .

30. Method according to claim 29, wherein said applying further comprises further applying the remaining portion of said decorating sheet means (18) to at least a further portion (61) of said support (16).

31. Method according to claim 30, wherein said further applying comprises causing to adhere said decorating sheet means (18) to said support (16) starting from the region thereof in which said at least a portion of said decorating sheet means (18) has been already applied.

32. Method according to claim 31, wherein said applying comprises pushing said decorating sheet means (18) onto said support (16) through an operating fluid.

33. Method according to any of the claims from 28 to 32, wherein before said applying it is provided temporarily coupling said decorating sheet means (18) to said applying means (2, 4) .

34. Method according to claim 33, wherein said temporarily coupling comprises sucking said decorating sheet means (18) on said applying means (2, 4) .

35. Method according to any of claims from 28 to 34, wherein said applying and/or said further applying comprises pressing said applying means (18) on said support.

36. Method according to any of claims from 28 to 35, wherein before said applying it is provided humidifying said decorating sheet means (18) so that it is possible to separate therefrom a protective sheet (17) .