WO2015036808A1

WO2015036808A1 - Security carrier for thermal printing

Info

Publication number: WO2015036808A1
Application number: PCT/HU2014/000082
Authority: WO
Inventors: Lajos DR. SZÉKELYHIDI; Géza IMRE; László ASZTALOS; Gyula LÁNGOS
Original assignee: Any Biztonsági Nyomda Nyrt
Priority date: 2013-09-16
Filing date: 2014-09-10
Publication date: 2015-03-19
Also published as: DE202014104386U1; AT14547U1; HU4337U

Abstract

This invention relates to a security carrier for thermal printing consisting of a base layer (1), a partition layer (2) arranged on the base layer (1) and a heat sensitive layer (3) fixed on the partition layer (2), wherein a security ink layer (7) containing irised pigment plates is arranged along a surface of the heat sensitive layer (3) opposite the partition layer (2).

Description

SECURITY CARRIER FOR THERMAL PRINTING

This invention relates to a security carrier for thermal printing consisting of a base layer, a partition layer arranged on the base layer and a heat sensitive layer fixed on the partition layer.

In all field of economic life, such as traffic as well, the best tools for individually displaying of variable information content generated by IT devices are the direct thermal printers, which can be used for automatic ticket machines operated either by a cashier or a user. The basis of protection against counterfeiting of the tickets thus produced is protecting the carrier paper. Forgers generally obtain carrier paper material used for most widespread counterfeiting procedures by chemically removing the original content of a ticket already used or having little value, and then the desired false content is applied to the surface of the carrier paper of the ticket by another printing technique (laser printing). Imitations made this way are of very high quality and can be detected only by instrumental analysis. Economic damages caused such a way for the service providers can be significant, so the manufacturers of carrier paper of tickets have developed different security solutions.

For prior art solutions the chemical protection is disposed in the heat-sensitive layer or carrier layer, for example base paper. Flocculent fibers usually paper-based tiny disks, called planchets, fluorescent of different colors by UV illumination, and having a diameter of 2-3 mm, into which a chemical reagent is built in for the purpose of chemical protection. However, the paint content of materials used for chemical protection can be removed without any trace by soaking the paper material in abundant water for a prolonged period of time. This type of protection is suitable for protecting against modification of a portion of the data content only.

In published document WOO 1/05603 a method for protecting information carriers against counterfeiting is disclosed, that involves applying a verification mark that can be visualized by additional external action so as to produce an optical effect. The verification mark comprises at least one layer of a non-transparent thermal identification coating comprising a composition that includes a polymer matrix containing melamine-formaldehyde and acrylic resins, and a thermo-sensitive substance of the cold-set ink type that contains 1-hexadecanol and 4- ethylphenol, butanol, amine resin and ethyl acetate. The external action may be heat or UV radiation, for example thermal printing. The drawback of the solution is that though the authenticity of the carrier paper can be verified, however, it does not provide protection against neither chemically removing of any members produced by thermal printing in the heat sensitive layer nor additionally making a surface print.

Therefore, the object of the present invention is to provide a security carrier for thermal printing, which eliminates disadvantages of prior art solutions, that is any forgery of its data content is clearly apparent to mere eye, and any actions for chemically removing of the original content of e.g. a ticket made by thermal printing and making additional prints become purposeless.

The object of this invention is achieved by providing a security carrier for thermal printing consisting of a base layer, a partition layer arranged on the base layer and a heat sensitive layer fixed on the partition layer, and a security ink layer containing iridescent pigment plates is arranged along a surface of the heat sensitive layer opposite the partition layer. A protective layer is arranged between the heat sensitive layer and the security ink layer comprising iridescent pigment plates, which layer is connected to the security ink layer by a non-releasable chemical bond.

The thickness of iridescent pigment plates is at most 3 [im.

The thickness of the security ink layer containing iridescent pigment plates is at most 5 um.

A protective layer is secured to the surface of the base layer opposite to the partition layer.

The ink layer comprises rare earth pigments emitting in infrared range.

The present invention will be disclosed in details in relation to preferred embodiments referring to the attached drawing. In the drawing

Figure 1 is a cross sectional view of a section of the security carrier for thermal printing according to the invention, Figure 2 a coloration established in the heat sensitive layer of the carrier is shown, and

Figure 3 shows the position of a print additionally printed onto the carrier after thermal printing.

Figure 1 is a cross sectional view of a section of the security carrier for thermal printing according to the invention. Base layer 1 of the carrier is made of paper in this embodiment; however, the base layer 1 may be formed of a different material, e.g. plastic. A partition layer 2 is placed on the base layer 1 that separates and at the same time secures as well the base layer 1 and heat-sensitive layer 3 of the carrier to each other. In the Figure a coloring 6 in the heat sensitive layer 3 is illustrated, which forms a part of the data content formed in the heat-sensitive layer 3 of the carrier after thermal printing. In a preferred embodiment shown in this Figure a protective layer 4 is arranged on the heat-sensitive layer 3, which serves to protect the heat-sensitive layer 3 against environmental effects. The protective layer 4 should be useful in those applications, where durability and protection of heat-sensitive layer 3 of the carrier against environmental effects must be enhanced. Therefore, the carrier according to the present invention can also be achieved without the application of the protective layer 4. The situation is similar in the case of a protective layer 5 arranged on a surface of the carrier opposite the separating layer 2 as it is applied in the embodiment shown in this figure.

In Figure 1 it is clearly seen that a security ink layer 7 is provided in the surface of the protective layer 4 opposite the heat-sensitive layer 3, which is made of a heat-resistant, iridescent flexographic ink, which is able to change its color or having changeable effect (persoprotect flexo ink), and effectively changes its color after thermal printing. As mentioned above by omitting the protective layer 4 the security ink layer 7 may be arranged directly on the heat-sensitive layer 3 as well, but the security ink layer 7 has to be placed along the surface of the heat sensitive layer 3 opposite to the partition layer 2, and it is applied onto the carrier preferably by printing.

The security ink layer 7 creates a strong and permanent bonding on the surface of the protective layer 4 by means of oxidation polymerization and cohesive forces. The security ink layer 7 is of an aery late-based, heat- resistant versnit containing 25% water-based heat-resistant acrylic emulsion, a total of 5.5% additives (anti-foaming agent, spread enhancer, pH adjuster, antibacterial and fungicide agent, isopropanol) and water 68,5 % to 64,5 %, and further contains 1-5% of iridescent and metalized, e.g. rutile based pigment plates, that reflect the light falling on them in different colors, depending on their structure. This mixture can be obtained by mixing in a mixer at 500 revolutions / min stirring speed for 20 minutes. While the white, for example paper base layer 1 forming a background reflects all colors and these will be added to the colors having given wavelength reflected by the pigment plates, the background color under the security ink layer 7 will be changed by the discoloring 6 created in the heat-sensitive layer 3 during thermal printing. A black discoloring 6 thus formed absorbs the incident colors, so that only colors reflected by the pigment plates become visible. A common feature of the iridescent pigment plates is a metallic and pearlescent luster, for the plates are made from a mixture of specially processed mica and titanium dioxide. The thickness of pigment particles having a lamellar structure in the security ink layer 7 is at least 3 microns, but their other dimensions size-up 200 microns as well. Therefore, the security ink layer 7 should be applied to the protective layer 4 by a thickness of 3-5 microns. As the acrylic emulsion has a very poor thermal conductivity, a layer thicker than 5 microns is not recommended. Unfortunately, the poor property of thermal conductivity is not improved by the iridescent pigment plates mixed with the ink. The security ink layer 7 applied forms a closed security ink layer 7 being resistant to water and other solvents. The security ink layer 7 should not be applied to the entire surface of the carrier, because the iridescent effect is stronger when the security ink layer 7 is veined.

Security ink layer 7 can be applied preferably to the area to be provided by data content of the carrier to be protected, because any data content can be read under protective layer 4 in any required extent. Security ink layer 7 already printed is clearly identifiable as being a security print, because of its color changing effect, and thermal printed data content can be read. Above the black, thermally printed discoloration 6 developed under the printed security ink layer 7 by the effect of thermal printing (e.g.. printing ticket information to the carrier), security ink layer 7 reflects purple or green etc. light from the incident light instead of previously reflected greenish-gray color. If the discoloration 6 (i.e. print images) printed by a thermal printer is removed from the heat-sensitive layer 3, eliminating at once the printability of the heat-sensitive layer 3 as well, any data can only be printed on the surface of the color changing security ink layer 7 by means of a printing process different from thermal printing, e.g. laser printing, but printing below the security ink layer 7 is impossible, as seen in Figure 2. Since the post printed print 10 is applied on the previously printed security ink layer 7, the color changing effect of the security ink layer 7 described above is ceased visibly by naked eye as well, that is the post printed print 10 covers the security ink layer 7 very clearly, and therefore the difference is clear, and so it provides an adequate protection against counterfeiting method mentioned above.

Furthermore, it is preferred to dispose an additional security material in the security ink layer 7, which is intended to protect the authenticity of traffic tickets. It is preferable that this security material cannot be detected by eye or even by simple tools, e.g. a hand glass, UV lamp, etc. Furthermore, it is advantageous that this safety material is suitable for automated security control to be performed inside an automated ticket machine as well. The security material is preferably active in infrared range emitting infrared radiation having specific spectral distribution in the range between 800-1200 nm in response to exciting radiation. Detection of this emission can be achieved by a handheld detector developed for this purpose. The detector preferably provides definite sound and light signals when the existence of security material is detected.

For the infrared emission is intensive and spectrally well separated from any other radiation emitted by any other material of the ticket and its prints, it is perfect for automated control. Security ink layer 7 containing rare earth pigments activated by erbium or ytterbium as well as iridescent, metalized, rutile based pigment plates is suitable for protecting both completing and authentication of a ticket.

Thermally printable security carrier according to the invention eliminates disadvantages of prior art solutions, that is any forgery of its data content is clearly apparent to mere eye, and any actions for chemically removing of the original content of e.g. a ticket made by thermal printing and making additional prints become purposeless.

Claims

1. A security carrier for thermal printing consisting of a base layer (1), a partition layer (2) arranged on the base layer (1) and a heat sensitive layer (3) fixed on the partition layer (2), characterized in that a security ink layer (7) containing iridescent pigment plates is arranged along a surface of the heat sensitive layer (3) opposite the partition layer (2).

2. The carrier according to claim 1, characterized in that there is a protective layer (4) arranged between the heat sensitive layer (3) and the security ink layer (7) comprising iridescent pigment plates, which layer (4) is connected to the security ink layer (7) by a non-releasable chemical bond.

3. The carrier according to any of claims 1 to 2, characterized in that the thickness of iridescent pigment plates is at most 3 um.

4. The carrier according to any of claims 1 to 3, characterized in that the thickness of the security ink layer (7) containing iridescent pigment plates is at most 5 μπι.

5. The carrier according to any of claims 1 to 4, characterized in that a protective layer (5) is secured to the surface of the base layer (1) opposite to the partition layer (2).

6. The carrier according to any of claims 1 to 5, characterized in that the ink layer (7) comprises rare earth pigments emitting in infrared range.