DE69608827T2 - Printable document containing means for detecting counterfeits - Google Patents

Abstract

A document for receiving printing comprises (a) a support layer of (semi)rigid material, e.g. paper, and (b) a colour layer on the support contg. (i) a first substance producing a colour reaction when contacted with (ii) a second substance, under exterior pressure. The second layer is incorporated in the body of the support layer.

Description

The present invention relates to a document suitable for receiving an imprint and comprising means enabling any forgery or any attempt at forgery to be detected.

The invention particularly relates to all black and white and/or coloured documents (such as a sheet, leaf, label, check) which are suitable for receiving a mechanical (printer) or manual (pen) imprint and where it is desirably/necessarily ensured with regard to forgery that the imprint has not been defaced or altered.

In particular, the invention can be applied to documents such as checks, (money, travel) tickets, labels of special products, official documents, etc.

The means used by counterfeiters are numerous and include chemical agents such as solvents, scratching and erasing agents designed to eliminate or delete certain data printed on the document in order to replace it with others, such as the amount and/or the recipient in the case of a check.

In the state of the art, known means have been proposed that should detect any attempt at forgery on the document itself.

Special inks such as magnetic inks were used to enter, for example, the CMC7 code of the check number or other data.

If the forger has this ink, which turns out to be not impossible, there are no obstacles to him scratching or erasing the data and replacing it with other data using this ink.

In addition, a complex and dense basic pattern is printed on the entire document in a known manner. Although this measure makes it possible to partially prevent the deletion or copying of this basic pattern and/or to make it difficult and cumbersome, it is nevertheless not completely reliable given the persistence and patience of some forgers.

Other methods involve enclosing chemical substances in the document paper that are insoluble in water but soluble in solvents, and can thus produce a detectable trace of visible color when using erasing chemical substances (basic reducing agents of the "ink erasers"). However, these methods do not allow a forgery to be detected by mechanical removal (scratching or erasing). In addition, it is also possible to remove the detectable trace using appropriate solvents.

Furthermore, another known means is to use a colored paper and on the side of the paper that to apply a layer of opaque, printable material (for example whitish wax) to the surface to which the print is to be applied. Any scratching or unauthorized printing will penetrate the opaque layer and reveal the colored paper underneath.

This well-known type of paper is very delicate, which proves to be annoying during use, and also has a particular aesthetic appearance, which limits its possible uses.

It is also known from patent WO 95/02512 to coat the supporting layer of a paper with a colouring layer containing microcapsules which, during printing or writing, open under the effect of pressure to release a colouring substance which can react with a reactant also added to this colouring layer. Such types of paper, which are also called self-copying, are used in batches which contain a first sheet of ordinary paper as the original and one or more additional, associated sheets which serve as duplicates.

This paper is relatively delicate due to the extremely sensitive ink layer, which requires great care in handling to avoid friction that causes unforeseen copying. Furthermore, the inking layer tends to to contaminate printing devices and especially ballpoint pens.

In this context, the present invention has the object of proposing a document that:

- can be printed on without damaging the printing equipment;

- can be handled without special care;

- can detect and report any attempt at counterfeiting by a chemical or mechanical process;

- allows the assurance of its authenticity

- can be used in numerous applications without restrictions on color, carrier layer, etc.

To this end, the document suitable for receiving a print according to the invention as defined in claim 1 is of the type comprising a support layer made of rigid or semi-rigid material.

According to a preferred embodiment, the second substance is distributed substantially uniformly throughout the entire thickness of the carrier layer.

The first substance is housed in microcapsules which are suitable to be destroyed under the effect of the pressure force and thus release this first substance.

A protective layer may be provided containing 100 parts natural calcium carbonate, 0.5 parts of a dispersant and 15 parts styrene-butadiene latex.

The carrier layer can be, for example, friction-coated paper, and the coloring layer can be arranged on its rough side.

The second substance has a surface density between 1.5 and 15 g/m_, preferably between 3 and 7 g/m_.

The reactant preferably consists of aluminium silicate based on montmorillonite or phenolic resins or modified silicon oxides.

The present invention will be understood from the following description, which refers to illustrative but non-limiting examples with reference to the accompanying drawings, in which:

- Fig. 1 shows a sectional diagram of an embodiment of the document according to the invention;

- Figure 2 the document of Fig. I being written on with a pen;

- Fig. 3 a variant with frictioned paper;

- Fig. 4 shows a further embodiment; and

- Fig. 5 shows yet another embodiment.

To better understand the drawing, the scale and dimensions of the figures have been enlarged.

The term document used is a generic term for sheet, check, paper, card, label, etc.

With reference to Fig. 1, the document according to the invention comprises a carrier layer 1 made of paper, on one of whose sides (in this case the lower side) a layer containing microcapsules 3 is applied. On the layer 2 a protective layer 4 is provided.

The reactants 5 are evenly distributed inside the paper carrier layer 1.

The support layer may consist, without limitation, of any type of paper and of any fibrous nature based on raw or recycled, natural or synthetic fibres and may contain additives commonly used in the paper sector, such as neutral, acidic or basic adhesive products, aluminium sulphates for acidic or pH-neutral bonding, resins, dyes or any other agent or additional compound required for the use and intended use of the paper.

The paper (support layer 1) can be subjected to any pre- and finishing process, such as pre-treatment on the conveyor belt and application of an aqueous composition (binder for coating, e.g. starch, polyvinyl alcohol, cellulose derivatives) by means of a gluing press.

The pretreatment of the paper carrier layer 1 comprises, according to the invention, the inclusion of reactants in the paper pulp, for example a mineral component such as, in particular, aluminum silicate (known under the trade name COPISTL N 210) which has been chemically modified on the basis of montmorillonite. The role of the reactants will be explained later.

A layer with a density of between 1 and 12 g/m_, preferably between 2 and 8 g/m_, containing microparticles 3 is applied to at least one side of the carrier layer 1. These have the shape of microcontainers with a wall made of natural or synthetic material (e.g. polyurethane) and describe an internal volume filled with a liquid phase containing the coloring substances, which may be dissolved in a solvent such as oil. The coloring substance, which is colorless in the state in the microcapsules, can cause a color reaction with the reactants 5 enclosed in the paper pulp 1, these agents consisting of acidic clay particles that can absorb electrons. The course of the color reaction will be explained later.

The coloring substance in the microcapsules contains one of the following components:

* Lactone violet crystal (blue color), * 3-diethylamino-methyl-anilinofluoran (black color),

* 3-Diethylamino-methyl-chlorofluoran (red colour),

* 3-Diethylamino-methyl-dibenzylaminofluoran (green colour).

The layer 2 consists of a binder added to the microcapsules 3, whereby the binder ensures the adhesion and hold of the microcapsules on the carrier layer 1. The binder can consist, for example, of latex, starch, polyvinyl alcohols. The amount of the layer applied is preferably between 1 and 12 g/m_ and in particular between 2 and 8 g/m_.

Then, microcapsules 3 are applied to the surface of layer 2, a protective layer 4 consisting of a mixture of mineral substances such as calcium carbonate, kaolin, talcum, etc., and binding agents such as latex, starch, proteins, polyvinyl alcohols, etc., in order to bind the mineral particles together and ensure the strength of this protective layer.

The protective layer 4 fulfils several tasks and in particular:

- it ensures the protection of the microcapsules against friction and accidental or accidental pressures;

- it enables the document to be printed on both sides by offset, typography or another process;

- it allows this surface to be written on without dirtying the ballpoint pen;

- using an appropriate formula, it enables the separation of superimposed documents by preventing subsequent documents from being printed while the first document is being written or printed on.

The following describes the use of Document 1 with reference to Fig. 2 with regard to the possible detection of fraud and counterfeiting.

In Fig. 2, the document of Fig. 1 is shown by way of example. On this document moves a printing device, which is represented by the end portion of a ballpoint pen 6 provided with a ball 7, the pen being known as such and connected to a supply of ink (not shown) which flows around the ball 7 to the lower portion and thus to the upper side 8 of the paper layer 1. The relative size of the ballpoint pen 6 has been deliberately reduced in relation to the dimensions of the document for the sake of better intelligibility.

When placing the pen 6 on the paper carrier layer 1, the user exerts a pressure that has a main vertical component from top to bottom, which is determined by the layer 1 is transferred to the layer 2 containing the microcapsules. The shell of these microcapsules is destroyed under the influence of pressure and releases the coloring substance enclosed therein. This substance now penetrates into the carrier layer 1. It should be noted that the coloring substance cannot flow to the lower section due to the presence of the protective layer 4.

Thus, the movement of the ballpoint pen 6 causes a colour reaction 9 in the mass of the carrier layer 1 and also on the back of the document.

Any attempt to erase a print on one of the sides (in this case the top side 8) of the carrier layer will reveal the colored marking 9. This cannot be erased.

Fig. 3 shows a section of a document made from a supporting layer 10 made of friction paper, i.e., it has a rough surface 11 on the side of the coloring layer 2 and the protective layer 4, and a smooth surface 12 on the opposite side. The rough surface 11 comprises surface irregularities in the form of depressions 13 and elevations 14, which are shown schematically in the figure. The microcapsules 3 take their place in the depressions 13. This type of paper can also comprise plant components with a grain size determined, whereby the compressibility of the supporting layer 10 can be increased ad hoc.

The irregularities (depressions 13 and elevations 14) and the compressibility of the carrier layer 10 dampen the pressure exerted by the printing devices on the upper side 12 of the carrier layer 10. This prevents, or at least limits, the transfer of the pressure to the document located below the one being printed. This has the advantage that no intermediate cardboard has to be placed under the document currently being printed.

As a modification, a layer 2 coloured with microcapsules 3 can be applied to each side of the carrier layer 1, and on top of this a protective layer can be applied.

In the embodiment of Fig. 4, the mass of the carrier layer 1 contains, in addition to the reactants 5, solid color pigments 15 with a fine grain size distributed throughout the mass. The pigments are water-insoluble but organically soluble, i.e. soluble as soon as they come into contact with organic solvents, whereby their color appears through this dissolution.

In another embodiment, not shown, the reactants are housed in the protective layer 4. This allows the color reaction on the back of the document to be increased in quantity.

In Fig. 5, another variant is shown in the form of a carrier layer 16, at least one side of which is covered with a layer 2' containing microcapsules 3, which in turn is coated with a protective layer 4.

This variant is similar to the embodiments described with reference to the other figures.

Color pigments 15' are distributed throughout the mass of the carrier layer 16, which are water-insoluble but organically soluble in solvents such as those used to dissolve/erase printer ink. The microcapsules 3' contain such a solvent. During the printing process, the microcapsules 3' open and release the solvent, which then reacts with the pigments 15' to color the carrier and the back of the document in their mass.

Specific examples of the practical implementation of the invention are described below.

example 1

On a paper support layer containing 5 to 6 g/m_ of chemically modified aluminum silicate based on montmorillonite (COPISIL N 210), a coating bath containing starch and a starch dissolution-inhibiting product such as melamine formaldehyde is applied to the paper side using a suitable known means (such as a glue press, roller system). The paper is then calendered. On the support thus prepared, a layer of 5 g/m_ of the following mixture, expressed as dry matter, is applied:

- 100 parts of microcapsules containing a colouring substance such as that described under known under the trade name BAYMICRON SLURRY RED;

- 5 parts of carboxyl styrene butadiene rubber (SB 230).

This preparation has a concentration of 30%. It is then further treated using an air brush coating device. 6 g/m of a mineral layer with the following formula (expressed in dry mass) is applied to the microcapsule layer:

- 100 parts of calcium carbonate (trade name HYDROCARB 90);

- 15 parts of acrylic latex styrene (SD 215);

- 2 parts of calcium stearate (NOPCOTE C 104).

This preparation is then applied at a concentration of 35% using an air brush coating device.

The document thus obtained can be printed on the front and/or back using any printing process, such as offset, without affecting the paper quality. All data or messages can be entered using a (blue or black) ballpoint pen or an impact printer.

This means that you get a black (or blue) print on the front and the same message in red on the back. Other colours can be used depending on requirements and selection of appropriate substances.

It becomes clear that with the help of the invention any fraud or forgery can be uncovered. Any attempt to erase, be it by scratching or erasing the original entry, leaves a trace not only on the mass but also on the back, since the original entry is on both the front and back of the document, making the fraud visible.

Furthermore, this document can also be used in the form of a bundle of two sheets. The first sheet represents the original in the example described below and the second sheet consists of a chemical self-copier coated with a CF (Coated Front) type recording layer or an autonomous self-copier.

When printing the original document and the corresponding second sheet, you get an original that has a trace of the information in red in its mass and on the back. On the second sheet (which is a duplicate) you also get an entry in red.

Two sheets can also be processed together in the manner described in Example 1, one underneath the other, with the same result.

When the invention is applied to documents such as cheques, the magnetic ink codes (known as CMC7) printed on a cheque made according to Example 1 appear on the back of the cheque in red (in the example described). This provides additional security, allowing any removal of or alteration to the CMC7 code to be detected.

The invention can equally be applied to all documents intended to be punched, stamped, sealed or, in general, imprinted with information or data intended to certify the authenticity of the document in question.

Finally, the printing of the original information on the back according to the invention offers the additional advantage of being able to detect any attempt to make a duplicate of a document by photocopying. It is known that photocopies, especially coloured ones, can be faithful reproductions and that a duplicate or copies with a high similarity to the original can thus be obtained. Photocopies of the front and back, on the other hand, always have a shift between the copy of the back and the copy of the front due to technological limitations in terms of mechanics. In this way, the document according to the invention makes it possible to detect this shift and thus any fraudulent attempt to make a photocopy.

Example 2

The dimensions and compositions are the same as in Example 1, with the exception that it is friction paper, i.e. with a smooth front and a rough back, and the coating process takes place on the rough side.

The peculiarity of the document thus obtained, especially in comparison with that of Example 1, is the compressibility and damping properties of the rough side, which prevents the transfer of the inscription from one sheet to the next when two sheets are superimposed.

This feature can be used to advantage in the market segment of security cheques, notes, cards and labelling. In certain cases, and in particular for certain types of product, it may be of interest to produce labels that certify the origin of the product and to prevent them from being altered or false labels from being produced.

Example 3

Starting from the conditions, formulation and composition of Example 1, 10% of vegetable matter with a fine grain size between 15 and 100 u is included in the mass of the paper support.

These plant-based substances increase the compressibility of the paper carrier layer, thereby protecting the microcapsules that can alter the subsequent sheet from friction.

By adapting the formulation of the protective layer accordingly, in particular by increasing the proportion of binder and/or by selecting binders with a higher viscosity, such a paper carrier can prevent copying onto the following sheet.

Example 4

Starting from Example 1, at least one side of the support layer is coated with a layer of microcapsules containing one or more colorless dyes and developing a blue color with the chemically modified aluminum silicate based on montmorillonite, which represents the second reactant enclosed in the mass of the support layer.

Example 5

Based on the formulation and composition of Example 1, the microcapsules contain a colorless dye that can produce a green color reaction with the reactants distributed in the carrier layer.

Example 6

Based on Example 1, the microcapsules contain a substance that can produce a black color reaction with the reactants.

Example 7

During production, 0.2 kg of red dye (Sudan Red 7B from Bayer) is added to 1,000 kg of dry paper mass. This dye is insoluble in water but soluble in other solvents. The paper is then calendered and then coated with microcapsules containing a solvent that can dissolve this dye. A protective layer (mineral particles) is then applied.

When writing with a ballpoint pen or printing with an impact printer, an indelible mark is created where the inscription is located. This example corresponds to Fig. 5.

Example 8

This example corresponds to the embodiment shown in Fig. 4.

For a paper support prepared in accordance with Example 1, dyes are added to the paper pulp in accordance with Example 7 and applied by means of a Glue press applies a coating bath of the following composition to the surface:

- 100 kg of oxygenated dry starch;

- 6 kg dye for checks AS (and BASF);

- 3 kg Chlorostain ......... (BAYER);

- 3 kg Reaction Yellow PS (BAYER).

The surface density is 5 g/m_.

Red-dyeing microcapsules and, as in Example 1, a protective layer are applied to the calendered paper.

The product thus obtained has the advantage that due to the color reaction between the dyes and the following solvents:

- organic solvents (ethyl acetate, petrol, etc.);

- chlorinated solvents (eau de javel);

- antioxidants (potassium permanganate, sodium hydrogen sulfite);

- acids;

- Bases,

any adulteration using chemical products can be detected.

Example 9

A layer of microcapsules containing an oil-soluble optical brightener is applied to a paper support which is free of optical brighteners, the microcapsule layer being covered with a protective layer as in Example 1.

An optical brightener is a product that reacts with light and in particular increases the proportion of ultraviolet radiation.

This document can be used to detect any forgery by contrast, comparing the writing on the front and back with a special light, such as the ultraviolet Wood lamp.

Example 10

A layer of microcapsules (source: BAYMICRON WJR from BAYER) is applied to a paper carrier. These contain a colorless, oil-soluble, coloring substance which, when in contact with chemically modified aluminum silicate based on montmorillonite, develops a gray color or a slight green or blue color, which makes it possible to read it with all infrared methods such as bar code readers, e.g. an infrared laser pen.

Claims (13)

1. Document suitable for receiving an imprint with - a carrier layer made of rigid or semi-rigid material such as paper, - a colouring layer applied to the support layer and containing a first substance capable of causing a colour reaction when brought into contact with a second substance contained in the mass of the support layer, - a protective layer applied to the colouring layer, - the carrier layer contains only the second substance, to the exclusion of the first substance, the latter being incorporated in the colouring layer in microcapsules which are capable of being destroyed under the effect of an external force exerted on the side of the carrier layer opposite the colouring layer or the protective layer, thus releasing the first substance. 2. Document according to claim 1, characterized in that the coloring layer contains a binder. 3. Document according to claim 1 or 2, characterized in that the microcapsules form a layer with a surface density of between 1 and 12 g/m², preferably between 2 and 8 g/m². 4. Document according to one of the preceding claims, characterized in that the protective layer comprises 100 parts of natural calcium carbonate, 0.5 part of a dispersant and 15 parts of styrene-butadiene latex. 5. Document according to one of the preceding claims, characterized in that the carrier layer is smooth or friction-coated paper on one side and that the coloring layer is arranged on its rough side. 6. Document according to one of the preceding claims, characterized in that the second substance has a density between 1.5 and 15 g/m², preferably between 3 and 7 g/m². 7. Document according to one of the preceding claims, characterized in that the second substance contains aluminium silicate based on montmorillonite or phenolic resins or modified silicon oxides. 8. Document according to one of the preceding claims, characterized in that the first substance is one of the components from Lactone violet crystal (blue color), 3-Diethylaminev-methyl-anilinoflourane (black colour), 3-diethylamino-methyl-anilinoflouran (red color), 3-Diethylamino-methyl-anilinoflourane (green color) contains. 9. Document according to one of the preceding claims, characterized in that the carrier layer comprises a Contains dispersion of synthetic products such as latex. 10. Document according to one of the preceding claims, characterized in that the protective layer contains the second substance. 11. Document according to one of the preceding claims, characterized in that the first coloring substance contains reactive dyes visible under ultraviolet and/or infrared irradiation. 12. Document suitable for receiving an imprint with - a carrier layer of rigid or semi-rigid material such as paper, comprising a second substance, - a colouring layer which contains a first substance excluding the second substance and is applied to the carrier layer, the first substance being suitable for causing a colour reaction when it is brought into contact with a second substance contained in the mass of the carrier layer, a protective layer, wherein the protective layer is applied to the colouring layer, the carrier layer contains only the second substance to the exclusion of the first substance, the latter being incorporated in the colouring layer in microcapsules which are capable of being destroyed under the effect of an external force exerted on the side of the carrier layer opposite the colouring layer or the protective layer, thus releasing the first substance, wherein the carrier layer has compressibility properties in its mass or on the surface of the coloring layer. 13. Document according to claim 12, characterized in that the carrier layer is smooth or friction-coated on one side and/or has vegetable additives with a suitable grain size distribution in its mass.