EP1165323B1 - Method for making scratchable blocks and support comprising same - Google Patents

Abstract

A method for producing blocks on a support that are designed to be removed by scratching. An ink jet printing technique is used to produce the blocks. The ink used is of the type with phase change. The method can be used to form a support containing an information or a graphic design on its surface and a scratchable block masking the information or graphic design. The scratchable block consists of juxtaposed and/or superposed dots of material. The method is particularly applicable to smart cards.

Description

The invention relates to a method for producing scratchable pavers on a support as well as a support comprising such a block.

Scratchable paving stones means any printed pattern on a support in order to be removed by simple scraping with a fingernail or any object of hardness sufficient, the objective generally being to discover an inscription or a design printed under said paving stone.

So far we have used technologies printing by screen printing or thermal transfer to make scrapable pavers.

In both cases, the material used for printing, has good covering power and sufficient adhesion to the support so as not to go away on its own but insufficient grip to be able to resist scratching.

However, such technologies are not particularly suitable for mass production of due to their low filing rate and / or complexity of implementation.

We are moving more and more towards the use en masse of such scrapable pavers, of course in the already known field which is the field of games such as lotteries, disposable tickets.

The depositor is also moving towards other uses, for example all portable media applications such as cards smart (bank smart card and / or wallet electronic and / or telephone chip card).

In such applications, the scratchable pad could be used to cover for example a useful number for the user.

Existing printing technologies for deposit scrapeable layers or scrapable pavers materials on paper pulp supports such as paper or cardboard existing today, that is to say thermal transfer or screen printing processes are not at all suited to the problem of productivity, as has been said, because of their low filing rate and / or their complexity of Implementation.

In addition, the realization of more scrapable pavers elaborate, that is to say for example multicolor, is also an element restrictive of currently used technologies.

US-A-4,540,628 describes an aluminum composite sheet with a hydrophilic coating for receiving base composition ink aqueous. This sheet can in particular serve as a lottery ticket support and include a number printed by an inkjet system and a removable opaque coating to hide the number.

US-A-4,312,268 relates to a method and apparatus for coating ink applied at high speed. He describes a moving strip which first receives a liquid by ink jet to produce an image, for example, then excess particles which adhere to the liquid to mask the image. The particles are brought in by contact with the passage of the strip in a hopper.
The image can be revealed later by scraping.

The subject of the invention is a method for resolve cadence and change issues dynamic size, shape and color of the scratchable paver in the context of industrial or other use.

The subject of the invention is therefore more particularly a process for producing scrapable pavers on a support mainly characterized in that it comprises the use of a jet printing technique ink.

According to another characteristic of the invention, the ink used is a change type ink phase (Hot Melt, in English terminology).

According to another characteristic, the inks used include oligomers and polyamides.

According to another characteristic of the invention, the support on which deposits can be made scrapable pavers can be a plastic support such than an integrated circuit card (chip card) whatever either the standard of the card and whatever the application.

The ink used contains the ester of an acid hydrogenated abietic (tackifier) and an agent plasticizer. In the case of printing on a support plastic, the abietic acid ester level hydrogenated enters the composition of the ink to height from 16.5% to 27% and that of the plasticizing agent will be 15% to 4.5% respectively.

According to another characteristic of the invention, the support can be rigid paper pulp (cardboard) or flexible (paper).

According to another characteristic of the invention, inkjet printing is achieved by one or more several print heads ordered according to the shape, size, and / or color of the paver achieve.

According to another characteristic, the heads printing devices used are of piezoelectric type.

The invention also relates to a support with information or graphics on one side and a scratch-off pad masking said information or graphics. It is characterized in that said block scratchable consists of justaposed material points and / or superimposed.

• les figures 1a et 1b illustrent un équipement permettant de mettre en oeuvre le procédé selon l'invention et
• la figure 2 illustre le résultat obtenu sur un support telle qu'une carte à puce au format ISO.

Other features and advantages of the invention will appear on reading the description which is given below and which is given by way of illustrative and nonlimiting example and with reference to the drawings in which:

• FIGS. 1a and 1b illustrate an equipment making it possible to implement the method according to the invention and
• FIG. 2 illustrates the result obtained on a support such as a smart card in ISO format.

The method of the invention can be implemented from differently by using one or more inkjet print head depending on the application. So, we will use one or more heads depending on the shape that we're looking at get for the scratchable pavement, possibly from its size relative to head size and also depending on whether you want to get cobblestones with one color or multiple colors.

An advantage of the present invention is that the print heads can be positioned in the existing production lines for paver manufacturing removable to replace current solutions.

We can therefore have one or more heads to inkjet to cover by construction or their mechanical positioning, the width of the surface useful to print. One or more inks of the same or of multiple colors will be ejected from the heads at inkjet when passing the object to be treated, which may therefore be of paper, plastic or other type.

Inks usable for these applications could for example be of phase change type (Hot Melt, in Anglo-Saxon terminology), which presents the advantage of solidifying on contact with the surface printed and which are compatible with a large variety of supports without special treatment. he these are waxes.

The main material that is used the most frequently for inkjet applications to phase change is the wax.

Indeed, the characteristics of this material are lend themselves very well to the cycles of elevation and temperature cooling required for this technology. The main uses of this type are generally oriented for paper or porous media applications that allow good adhesion of the wax-based ink in the support fibers.

However, in the context of this invention, the wax has the main defect of not being sufficiently adherent to plastic materials, which generates insufficient abrasion resistance in part of this app.

For this, the method described in the invention, uses phase change inks that include oligomers and polyamides. This formulation, used by some ink manufacturers, allows improve adhesion on plastic supports as well as facilitate the achievement of colors specific requirements for this application.

Today, products based on this technology are available from companies like Data Product, Brother, Polaroid, Markem and Tektronic. These products are generally intended for printing of paper or cardboard type supports.

• mono-amide   47 %
• Tetra Amide   21.5 %
• Agent tackifiant "Tackifier"   27 %
• Agent plastifiant "Plasticizer"   4,5 %

The ink formulations used by the different manufacturers are very similar and we can for example quote by reference Color Stix inks from Tektronic can be summarized as follows:

• mono-amide 47%
• Tetra Amide 21.5%
• Tackifier 27%
• Plasticizer 4.5%

The tackifier product is an adhesive agent for ink (in English Tackifier which corresponds to a hydrogenated abietic acid ester).

Phase change inks generally have a softening temperature around 90 ° C and physical characteristics compatible with the piezo inkjet technology from 130 ° C.

In the context of the invention, the use of inks generally used for applications paper does not allow sufficient adhesion on plastic support for the application considered. In order to improve the adhesion of the ink, wording changes are required.

In order not to increase too much the tackifiers for inks, the depositor preferred decrease the plasticizing agents which are generally polymers, better suited for applications plastic.

An example of a plasticizer used in the scope of the invention is Di-isonomyl phthalate.

• tackifiant : de 16,5% à 27%
• plastifiant : de 4,5% (avec 27% de tackifiant) à 15% (avec 16,5% de tackifiant).

The percentages of tackifier and plasticizer in the composition of the ink may be:

• tackifier: from 16.5% to 27%
• plasticizer: from 4.5% (with 27% tackifier) to 15% (with 16.5% tackifier).

The thickness of ink deposited varies depending on the print resolution, ink formulation as well as temperature, the nature of the substrate when the drop hits the support.

In the context of the invention, the thickness deposited varies between 8 to 20 µm depending on the parameters mentioned above.

E equipment for jet printing ink of scrapable pavers according to the process of the invention has been represented schematically on Figures 1a and 1b.

This equipment will include for example a head printing 1n controlled by electronic control 2 which will include a PG steering program adapted to the shape and size of the pattern you want to make.

The electronic control 2 is not original in ones existing orders for machines to printing used in paper printers can be used for example to order this printhead. Of course, the parameters concerning the linear speed of displacement of the head, the flow d of the ink flowing in nozzles of the head as well as the pattern program perform in one pass or in several passages of the head on the support, have entered the memory of the print head control program.

The print head is supplied with ink by a heating tank 3, due to the use of ink phase change based on the variation of temperatures, this also in a conventional manner. The tank bears the reference 3 in the figures.

1n inkjet heads, and more especially technology-based heads piezoelectric, allow to reach linear speeds one to two meters per print second, which greatly exceeds in terms of rate what current technologies are capable of to realise.

Another very important advantage of this invention is that the method allows for custom scratch off prints addressing capabilities of inkjet heads.

Indeed, depending on the application and the resolution several heads can be used inkjet. Each head will have a specific color in order to produce different graphic effects at high speed and which may also be different from support to another by changing the current parameter printing. This change of parameter can be realized by means of an input-output device, connected to the control electronics 2, referenced 4 on the diagram in Figure 1b.

FIG. 2 illustrates a support 1 on which there is printed a scrapable P block according to the the invention. This block P has been placed in a zone Z which is defined, relative to the borders of the card for example, in the program that pilots the print head.

The shape of the paving stone produced and the flow of the ink to obtain the desired thickness e of the ink which is filed, are also defined in this program.

FIG. 2 illustrates an exemplary embodiment on a plastic support S such as a chip card ISO format. As we said before, this support could be a paper or cardboard support produced according to the method of the invention. Of course, the ink can be replaced by a subject and we will then speak of jet of material in the broad sense.

The invention particularly relates to the use of material jet or ink jet techniques in which it is possible to order or control individually each jet of a drop or blocks of n simultaneous jets of one drop each.

More specifically, the support comprises a information or graphics on one side and one block scratch-off masking said information or graphics. The scratchable pad consists of material points juxtaposed and / or superimposed. These points result from the impact of drops of matter, especially drops ink sprayed by material jet in general or jet ink on the support.

The dots have a resolution higher than 100 DPI. Preferably the resolution is understood between 100 and 600 Dpi.

When using the color effect offered by technology of the invention we can get a paver with dots of different colors.

Advantageously, the colored dots can form a decorative pattern or information or a security element such as guilloches to increase jamming or camouflaging hidden information.

The security reason can be regular or random, visible or not from the outside. He can be in the same color as the information or graphics affixed to the support so as to merge with her or him. The pattern can be directly in contact with, the information or the graphics or be about the same level. He can understand at minus one layer of dot of material or ink on top of homogeneous color or not.

Claims (14)

1. A method of producing scratch pads on a medium, characterised in that it comprises the use of an ink-jet printing technique.
2. A method of producing scratch pads according to Claim 1, characterised in that the ink used is an ink of the phase-change type.
3. A method of producing scratch pads according to Claim 1 or 2, characterised in that the inks used comprise oligomers and polyamides.
4. A method of producing scratch pads according to Claim 1, characterised in that the medium is made from plastic.
5. A method of producing scratch pads according to Claims 2 and 4, characterised in that the ink comprises the ester of a hydrogenated abietic acid and a plasticiser and in that the amount of this ester forms part of the composition of the ink to the extent of 16.5% to 27% whilst that of the plasticising agent is respectively from 15% to 4.5%.
6. A method for producing scratch pads according to Claim 1 or 3, characterised in that the medium is made from paper pulp which is either rigid (cardboard) or flexible (paper).
7. A method of producing scratch pads according to any one of the preceding claims, characterised in that the ink-jet printing is obtained by one or more print heads controlled according to the shape, size and/or colour of the pad to be produced.
8. A method of producing scratch pads according to any one of the preceding claims, characterised in that the ink-jet print heads are of the piezoelectric type.
9. A medium comprising a scratch pad produced according to any one of Claims 1 to 8.
10. A medium comprising information or a graphic on one face and a scratch pad masking the said information or graphic, characterised in that the said scratch pad is composed of juxtaposed and/or superimposed dots of material having a resolution greater than 100 dpi.
11. A medium according to one of Claims 9 to 10, characterised in that the dots have different colours.
12. A medium according to Claim 11, characterised in that the dots of different colours form a pattern.
13. A medium according to Claim 12, characterised in that the dots of different colours form a regular or random security pattern, visible or not from the outside.
14. A medium according to Claim 13, characterised in that the security pattern is directly in contact with the said information or the said graphic, or is substantially at the same level.

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