WO2008056241A2

WO2008056241A2 - Plant and method for decoration by means of ink-jet technology

Info

Publication number: WO2008056241A2
Application number: PCT/IB2007/003414
Authority: WO
Inventors: Antonio Maccari
Original assignee: Antonio Maccari
Priority date: 2006-11-08
Filing date: 2007-11-07
Publication date: 2008-05-15
Also published as: EP2079591A2; WO2008056241A3; ITPI20060122A1

Abstract

It is a plant (10; 10A) for decorating tiles (13) that works in parallel so as to be able to decorate simultaneously several tiles that move on distinct lines. The plant provides a series of decorating stations (11; 11A), each of which comprising an ink- jet head (17) associated with movement means (19, 20) that moves the ink- jet head (17) on the underlying, preferably stationary, tile.

Description

PLANT AND METHOD FOR DECORATION BY MEANS OF INK-JET

TECHNOLOGY

The object of the present invention is a decorating plant for decorating by ink-jet technology.

In particular, the invention relates to the technical field of the industrial decoration of ceramic tiles, but the adopted solution can be used to print any serially produced item requiring a decorating or printing operation.

Ink-jet printing technology is now a mature and widely used technology used for printing and/or decorating various materials, including paper, plastics, textiles, wood and also ceramic tiles .

With particular reference to the latter applicationa.1 field, for decorating ceramic tiles special ceramic inks have to be used that are '"compatible" with the high temperatures necessary for bestowing the physical features on the ceramic tiles.

In the production of ceramic tiles, in order to optimise production costs, it is necessary for the firing kiln for firing the tiles to work always at maximum production capacity.

In a tile decorating plant, the number of tiles to be decorated in the unit of time is thus determined by kiln capacity.

For example, in the case of productive capacity of a kiln of approximately 320 m²/hour and with tiles measuring 30 x 30 cm, about one tile per second has to be decorated, a combination that is perfectly compatible with the decorating capacity of silk-screen printing machines but is not compatible with the typical speed of an ink-jet printing machine, which is generally slower.

A type of decorating plant for decorating ceramic tiles by ink-jet printing is known on the market, which plant provides performance that is compatible with the supplying needs of modern ceramic kilns. A plant of this type is also known from European patent EP

1038689.

Such plant, in order to reach the desired speed, uses a considerable number of heads aligned on and transverse to the tile-conveying line.

In this way the tiles are decorated whilst they move along the conveying line at a speed of approximately 20-30 metres per minute (the printing heads are fixed whilst the tiles move) .

Such plant nevertheless has some drawbacks due to: the constructional complexity of controlling the hundreds of printing heads used in such configuration; the need to clean periodically the heads by means of complex mechanisms to be positioned underneath the heads to collect the purging ink; waste of expensive ceramic ink at each purging step; production downtime due to most trivial drawback, also due to a single printing head of the tile-decorating plant .

In general, it can be said that the current plants for decorating ceramic tiles by ink-jet printing are complex, costly and carry high risks of stopping production. The basis of the problem of complexity is the fact that the plant has to produce a quantity per minute of square metres of decorated tiles so as to maintain the kiln fully loaded. As the number of tiles per square metre varies according to the dimension of the single tile, the plant, in particular the components linked to printing, has to be dimensioned to the maximum conveying speed and the maximum dimension of the tiles .

This inevitably leads to an evident waste of expensive components, in particular to using a large number of printing heads .

The main object of the present invention is to solve the problems disclosed here in relation to plant for decorating ceramic tiles by ink-jet technology. In the context of the main object disclosed above, an important object of the present invention is to provide a decorating plant for decorating by ink-jet technology, particularly for ceramic tiles, that has low structural complexity and at the same time enables great productivity. A further important object of the present invention is to provide a decorating plant for decorating by ink-jet technology, particularly for ceramic tiles, that has a high degree of operating flexibility.

Still an important object of the present invention is to provide a decorating plant for decorating by ink-jet technology, particularly for ceramic tiles, that enables an undesired production stop to be avoided.

These and still other objects, which will be become clearer below, are achieved by a decorating plant for decorating by ink-jet technology, particularly for decorating tiles, characterised in that it comprises: a plurality of independent stations for decorating tiles, but arranged for working together in parallel, each said decorating station being crossed by a respective movement line for the product being decorated, a common supply line of the product to be decorated for said movement lines, a common removing line of the decorated product exiting from said movement lines, each said decorating station further providing a stopping zone for a single product to be decorated, above said stopping zone there being arranged at least one ink-jet printing head associated with movement means suitable for moving the at least one head on the product, stationary in said zone, to perform the decoration.

Further features and advantages of the invention will become clearer from the description of a preferred but not exclusive embodiment thereof, in the attached tables of drawings, in which: Figure 1 is an axonometric , schematic view of a single decorating station of a decorating plant for decorating ceramic tiles according to the invention, shown during the tile decorating step;

Figures from 2 to S show various decorating steps of decorating a single tile in the station in Figure 1;

Figure 6 is an axonometric overall view of a decorating plant according to the invention, using the decorating station illustrated in the preceding figures;

Figure 7 is a plan and side view of a different solution for implementing a decorating plant according to the invention, using the decorating station illustrated in the preceding figures.

With reference to the previously quoted figures, a ceramic tile decorating plant, according to the invention, is indicated overall by the number 10.

With particular reference to Figure 6, the plant 10 comprises a plurality of decorating stations 11 arranged for working together in parallel.

This means that the decorating stations 11 decorate simultaneously tiles 13 that are different from one another.

To this end, each decorating station 11 can apply a complete decorative pattern to a tile 13. A single tile 13 is thus decorated in a corresponding decorating station 11, without interacting with the other decorating stations Ii that work in parallel.

Each decorating station 11 is traversed by a respective movement line 12 for the product being decorated, which, in this example, consists of ceramic tiles indicated by the number 13.

With the number 14 there is indicated a common tile supply line 13 supplying tiles to the movement lines 12, whilst with number 15 there is indicated a common line for removing the decorated tiles 13 exiting from the movement lines 12.

In particular, in this embodiment, the supply line 14 and the removing line 15 are parallel to one another, whilst the single movement lines 12 are transverse thereto; not shown in the Figures, at the head of the movement lines 12 there is removal means for removing the tiles from the supply line 14.

It is clear how other arrangement configurations of the various lines are possible, however with the proviso of making the decorating stations 11 work parallel.

As visible in Figure 6, the decorating stations 11 are positioned substantially at the same height as a respective movement line 12.

In particular, each decorating station Ii provides a stopping zone and/or passage zone 16 for at least one tile to be decorated.

Above the stopping zone and/or passage zone 16 of the station

11 there is arranged at least one ink-jet printing head 17 associated with movement means 18 suitable for moving the at least one head 17 on the stationary and/or passing tile 13 in the zone for performing the decoration.

The decorating station 11 is stationary, whilst the movement line 12 passes through decorating station 11.

When a tile 13 arrives at the decorating station 11, at the stopping zone 16, the movement line 12 stops or anyway slows.

At this point the movement means 18 moves the printing head

17 on the preferably stationary tile, decorating the tile.

In particular, in this embodiment, the movement means 18 of the at least one printing head 17 becomes concrete in two guides 19, arranged on opposite sides of the stopping zone 16 parallel to the advance direction of the tile 13. The guides

19 act as sliding guides for a bridge element 20 on which there is slidingly arranged the at least one ink-jet printing head 17; naturally, with the bridge element 20 and with the at least one printing head 17 there is arranged translating means that is in itself known.

With particular reference to Figure 7, in an alternative embodiment, the plant 1OA comprises a plurality of decorating stations 11A arranged for working together in parallel. A movement line 12A, suitable for moving the product to be decorated, passes through the decorating stations HA. In this embodiment, the product to be decorated consists of ceramic tiles indicated by the number 13.

By the number 14A a common supply line is indicated that supplies tiles 13 to the movement line 12A, whilst with the number 15A a common removing line is indicated that removes the decorated tiles 13 exiting from the movement line 12A.

In particular, in this embodiment, the supply line 14A, the supply line 12A and the removing line 15A are continuous in relation to one another and extend in the same advance direction.

It is evident that other arrangement configurations of the various lines are possible, but with the proviso that they enable the decorating stations HA to work in parallel.

In practice, when the tiles 13 arrive on the supply line 14A, preferably becoming deposited first in a store 21, they are conveyed toward the decorating stations HA, so that the first tile stops in the decorating station HA that is further from the supply line 14A, the second tile stops at the decorating station adjacent to the one further from the supply line 14A, and so on until the last tile is deposited in the decorating station HA nearer the supply line 14A.

As soon as a tile is positioned in the corresponding decorating station, decorating thereof may begin.

As visible in Figure 7, the decorating stations HA are positioned substantially in series, one after the other.

Nevertheless, the tiles 13 are conveyed to successive decorating stations HA so that the stations can decorate in parallel different tiles 13.

In particular, each decorating station HA provides a stopping zone and/or passage zone for a single tile to be decorated.

Above the stopping zone and/or passage zone there is arranged an ink-jet printing head 17 associated with movement means 18 suitable for moving the head 17 on the tile 13 that is stationary and/or moving in the zone 16 for making the decoration.

The decorating station HA is stationary, whilst the movement line 12A passes through the decorating station HA.

When a tile 13 arrives at the decorating station HA, at the

Stopping zone and/or passage zone 16, the movement line 12A stops or slows.

At this point the movement means 18 moves the printing head

17 on the preferably stationary tile, decorating the tile.

Once the decoration has been completed, the tiles positioned on the various decorating stations HA are pushed onto the removing line 15A, preferably being first deposited in an outlet store 22.

In Figures 2-3-4-5 the various steps for printing a single tile 13 are illustrated: in Figure 2 the at least one printing head 17 is positioned at a corner of a tile 13 and starts a translation movement along the bridge element 20, decorating a transverse strip of the tile (Figure 3) ; then the bridge element 20 is translated forwards on the guides 19 by a distance substantially equal to the width of the strip that has just been decorated (Figure 4) ; at this point the at least one printing head 17 translates again, but in an opposite direction, along the bridge element 20, decorating a new strip (Figure 5) ; this is followed by a new forward translation of the bridge element 20, and so on until the entire surface of the tile 13 has been completed.

Once the decoration has terminated, the movement line 12 is restarted, making the tiles advance.

The supply line 14 of the tiles to be decorated and the removing line 15 of the decorated tiles are of the continuous movement type, whilst, as now disclosed, the movement lines

12 have a discontinuous movement dictated by the stopping of the tiles in the decorating stations 11.

Suitably, the plant 10 comprises a minimum number of decorating stations 11 substantially directly proportional to the stop time of the tiles 13 to be decorated in the respective decorating stations 11.

In this manner the number of decorated tiles produced in the unit of time is suitable for supplying modern tile kilns. In order to ensure maximum flexibility for the plant, at the inlet to the movement lines 12 on which there are the decorating stations 11, there are the respective stores for accumulating the tiles 13 to be decorated coming from the supply line 14; similarly, at the outlet from the movement lines 12, there are the respective stores for accumulating the tiles 13 intended for the removing line 15; in the Figures these stores are not shown but can be made using the usual technologies adopted for moving tiles on industrial processing lines.

It is evident that the components of the plant are managed in an automated manner by control means of electronic type that enables all the work steps to be supervised and the resources to be reallocated in the event of unexpected jams in any decorating station, thus ensuring constant production and minimising total plant jams.

It has been ascertained in practice that the invention thus described achieves the objectives and purposes for which it is intended.

Actually, with the present invention a plant is provided consisting of a parallel system of decorating stations, so that they can decorate in parallel the tiles necessary for supplying a ceramic kiln at maximum productive capacity. This work in parallel of the decorating stations enables to provide a decorating system the dimensions of which are configurable, but above all enables the redundancy to be obtained that is necessary for overcoming a possible jamming of one or more decorating stations.

This plant has at the inlet to the movement lines of the tiles a mechanism that accepts the tiles at the rate that is typical of the presses, which, also by means of a possible store, is capable of returning the tiles at a different rate, even with the same quantity in terms of tiles per unit of time.

In practice the continuous process with which the tiles arrive is connected with the discontinuous decorating process_/ simultaneously maintaining a number of decorated tiles over time that is equal to a typical process that operates continuously.

Making the decorating step discontinuous enables a very simple decorating station to be used, based on a printing system consisting of an ink jet head for each ink, moved by a system with Cartesian axes on the tile, which remains substantially stationary during decoration.

With this configuration it is simple to reach the operating speeds required by the ceramics industry; for example if a tile measuring 30 cm x 30 cm is required each second and the simplified decorating station produces one every 5 seconds, it is sufficient for 5 decorating stations to operate in parallel to produce the quantity required by the plant.

The qualifying features of the new plant can thus be summarised as: optimising the resources necessary (number of heads and relative piloting circuitry) , to reduce total number of heads required; scalability of the number of decorating stations,- redundancy of the decorating stations,- connection between continuous arrival of the tiles and discontinuous decorating.

The advantages that derive from the new plant structure are summarisable in terms of greater decorating quality, flexibility, redundancy, scalability and economy in the creation of the plant.

In terms of quality, the possibility of decorating the tile when the tile is stationary (and not moving, as occurs with known plants) enables the quality of the decorating result to be increased, for example by enabling the definition to be increased by means of a double number of strokes . In terms of flexibility, the greater time required for decorating tiles of greater dimensions is compensated by the fact that a smaller number of pieces have to be decorated in the unit of time.

In terms of redundancy, with the present structure it is possible to configure the plant so that it can continue to operate, with equal or less capacity, even if one of the printers is stationary because broken.

In terms of scalability, the present plant enables printing capacity to be distributed over several stations, thus enabling the system to be sized gradually.

In terms of savings, the parallel system of decorating stations employs approximately a quarter of the number of printing heads required by traditional ink-jet printing systems using fixed heads, with significant constructional saving.

A decorating system for decorating by ink-jet technology, particularly for decorating tiles, comprises:

- a plurality of decorating stations arranged for working together in parallel, each of said decorating stations being traversed by a respective movement line for the product being decorated, each of said stations further providing at least one ink- jet head associated with movement means suitable for moving the head on the product being decorated, underneath the head.

Advantageously, the system further comprises at least one common supply line of the product to be decorated for said movement lines.

Advantageously, the system further comprises at least one common removing line of the decorated product exiting from said movement lines.

Advantageously, each decorating station provides a stopping zone for at least one product to be decorated, above said stopping zone there being arranged at least one ink-jet printing head associated with movement means suitable for moving at least one same head on the product, stationary in said zone, to perform the decoration.

The system is carried out in particular with a plant.

The invention concerns a decorating plant for decorating by ink-jet technology, particularly for decorating tiles, comprising: a plurality of decorating stations arranged for working together in parallel, each of said decorating station being traversed by a respective movement line for the product being decorated, each of said stations further providing at least one ink- jet head associated with movement means suitable for moving the head on the product being decorated, underneath the head.

Advantageously, the plant further comprises at least one common supply line supplying the product to be decorated for said movement lines.

Advantageously, the plant further comprises at least one common removing line of the decorated product exiting from said movement lines.

Advantageously, each decorating station provides a stopping zone for at least one product to be decorated, above said stopping zone there being arranged an ink-jet printing head associated with movement means suitable for moving the head on the product, stationary in said zone, to perform the decoration.

Advantageously, said supply line supplying the product to be decorated and/or said removing line removing the decorated product are of the continuous movement type, whilst said movement lines have a discontinuous movement dictated by the stopping of the products in the decorating stations. Advantageously, the plant comprises a number of decorating stations proportional to the time, in seconds, of the stop of the products to be decorated in the respective decorating stations. Advantageously, the plant comprises, at the inlet to said supply line, at least one store for accumulating the products to be decorated.

Advantageously, the plant comprises, at the inlet to said movement lines on which there are said decorating stations, respective stores accumulating the products to be decorated coining from said supply line.

Advantageously, the plant comprises, at the outlet from said removing line, at least one store for accumulating the decorated products .

Advantageously, the plant comprises, at the outlet from said movement lines on which there are said decorating stations, respective stores accumulating the decorated products intended for said removing line.

The invention that is thus conceived is susceptible of numerous modifications and variations, all being part of the inventive concept; further, all the details can be replaced by other technically equivalent elements .

In practice, the materials used, provided that they are compatible with the specific use, and the dimensions, can be of any type according to needs and the state of the art.

Where the features and techniques mentioned in any claim are followed by reference signs, such reference signs have been added for the sole purpose of increasing the intelligibility of the claims and consequently such reference signs have no limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. Decorating plant for decorating products (13), particularly tiles, by ink-jet technology, characterised in that it comprises : a plurality of decorating stations (11; HA) arranged for working in parallel to one another; at least one movement line (12; 12A) for moving said products (13) through said decorating stations (11; HA) ; each decorating station (11; HA) comprising at least one ink-jet head (17), so that each decorating station (11; HA) decorates a respective product (13) .

2. Plant according to claim 1, wherein each decorating station (11; HA) comprises movement means (19, 20) suitable for moving the corresponding head (17) with respect to the underlying product (13) .

3. Plant according to claim 1 or 2, wherein there is provided a plurality of movement lines (12) , each movement line (12) passing through a corresponding decorating station (li) .

4. Plant according to any preceding claim, and further comprising a common supply line (14; 14A) for supplying said products (13) to said at least one movement line (12; 12A) .

5. Plant according to claim 4, as appended to claim 3, wherein the movement lines (12) of said plurality are transverse to said common supply line (14) .

6. Plant according to claim 5, or according to claim 4 as appended to claim 3, and further comprising, at the inlet to said movement lines (12) on which there are said decorating stations (11) , respective stores for accumulating the products (13) to be decorated coming from said common supply line (14) .

7. Plant according to claim 4, wherein said at least one movement line (12A) is continuous with said common supply line (14A) .

8. Plant according to claim 4 or 7 , wherein said at least one movement line (12A) and said common supply line (14A) extend along a common direction.

9. Plant according to any one of claims 4 to 8, and further comprising, at the inlet to said common supply line (14; 14A) , at least one store (21) for the products (13) to be decorated.

10. Plant according to any preceding claim, and further comprising a common removing line (15; 15A) for removing the decorated products (13) exiting said at least one movement line (12; 12A) ,

11. Plant according to claim 10, as appended to claim 3, wherein said common removing line (15) is transverse to the movement lines (12) of said plurality.

12. Plant according to claim 10, wherein said common removing line (15A) is continuous with said at least one movement line (12A) .

13. Plant according to claim 10 or 12, wherein said common removing line (15A) and said at least one movement line (12A) extend along a common direction.

14. Plant according to any one of claims 10 to 13, and further comprising, at the outlet from said common removing line (15; 15A) , at least one store (22) of the decorated products (13) .

15. Plant according to any one of claims 10 to 14, as claim 10 is appended to claim 3, and further comprising, at the outlet from said movement lines (12) on which there are said decorating stations (11) , respective stores accumulating the decorated products (13) intended for being received from said removing line (15) .

16. Plant according to any one of claims 4 to 15, wherein aaid common supply line (14; 14A) of the product (13) to be decorated and/or said common removing line (15; 15A) of the decorated product (13) are of the continuous movement type, whilst said at least one movement line (12; 12A) has a discontinuous movement dictated by the stops of the products (13) in the decorating stations (11; HA) .

17. Plant according to any preceding claim, wherein each decorating station (11; HA) provides a stopping zone (16) for at least one product (13) to be decorated, above said stopping zone (16) there being arranged a corresponding ink-jet head (17) movable with respect to said product (13), so as to decorate said product (13), stationary in said stopping zone (16) .

18. Plant according to any preceding claim, comprising a number of decorating stations (H; HA) proportional to the time, in seconds, of the stop of the products (13) to be decorated in the respective decorating stations

(11; HA) .

19. Method for decorating products (13), particularly ceramic tiles, by ink-jet technology_/ comprising the steps of : supplying said products (13) to a plurality of decorating stations (11; HA) , each decorating station (H; HA) comprising at least one ink-jet head (17) ; decorating each product (13) in a respective decorating station (11; HA) of said plurality, said decorating stations (11; HA) working in parallel; removing said products (13) from said decorating stations (11; HA) .

20. Method according to claim 19, wherein said products (13) are supplied to said decorating stations (11; HA) by means of a common supply line (14; 14A) .

21. Method according to claim 20, wherein said products (13) are moved continuously along said common supply line (14; 14A) .

22. Method according to claim 20 or 21, wherein said products (13) are conveyed from said common supply line

(14) to said decorating stations (11) through a plurality of movement lines (12) , each decorating station (11) being traversed by a corresponding movement line (12) .

23. Method according to claim 20 or 21, wherein said products (13) are conveyed from said common supply line

(14A) to said decorating stations (HA) through a movement line (12A) that traverses in sequence said decorating stations (HA) .

24. Method according to any one of claims 19 to 23, wherein said products (13) are removed from said decorating stations (11; HA) by a common removing line (15; 15A) .

25. Method according to claim 24, wherein said products (13) are moved continuously along said common removing line (15; 15A) .

26. Method according to any one of claims 19 to 25, wherein said products (13) are moved intermittently whilst they pass through said decorating stations (11; HA) .

27. Method according to any one of claims 19 to 26, wherein, in each decorating station (11; HA), the corresponding at" least one head (17) moves to decorate a stationary product (13) .

28. Method according to any one of claims 19 to 26, wherein, in each decorating station (11; HA) , the product (13) to be decorated is slowed.