FR2782470A1 - Method of printing on a document to provide control of its authenticity - Google Patents

Abstract

The document (1) has over part of its surface a film (3) which is marked with a colored ink. The film is coated with an iridescent or reflective ink (4), which allows the markings to be seen by the naked eye, but prevents copying of the document by photographic techniques by reflecting or diffusing incident light from copiers.

Description

The subject of the present invention is a method of printing a support.

  allowing to check its authenticity as well as a printed medium which can be authenticated without particular instrumentation, and

  may include non-photocopiable information.

  In order to avoid the issue of false documents or printed media, we used different printing methods and we provided the security design media consisting of very fine lines of different colors forming complex figures of so that reproduction by photographic means such as photocopying is difficult. However, the development of reproduction techniques has made it possible, at least in certain cases, to overcome this difficulty. Another solution consists in the manufacture of supports, at least part of the surface of which comprises relief lines produced by intaglio. In particular, it has been proposed to produce a transient image formed by parallel raised lines. Alternatively, the transient image is only detectable through an appropriate transparent screen, or by illuminating the support with a lamp

special light.

  These solutions have contributed to making it difficult, if not impossible, to manufacture false supports because no photographic device can produce a three-dimensional reproduction. However, these solutions have the disadvantage of requiring special instrumentations such as a screen, lens or special light lamp to carry out the authenticity check and therefore to render it

  difficult during everyday use of said supports.

  The object of the invention is to remedy these drawbacks mentioned above by proposing on the one hand, a printed support which can be authenticated by a non-specialized person and without having recourse to any particular instrumentation such as a special light lamp, screen, lens and on the other hand, a method of printing said support. The first object of the invention is a method of printing a support making it possible to control its authenticity, characterized in that it comprises the following steps:

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  - a film comprising at least one color ink is produced on at least one area of the support, and - an iridescent reflectance ink is deposited by superimposition on said film, said color ink forming the film being such that the film is perceptible in transmittance under the printing of said ink

iridescent in reflectance.

  According to a first variant, the support consists of a paper substrate on which, successively, the film is produced and

deposits the iridescent ink.

  According to a second variant, the support consists of a first paper substrate on which said film is produced and by a second translucent substrate on which the iridescent ink is deposited and

  in that said translucent substrate is fixed on the paper substrate.

  According to another characteristic, the iridescent ink is deposited in such a way that it partially covers the film, allowing it to remain

  a portion of said film in the form of patterns.

  According to yet another characteristic, figurative patterns and / or text are also produced on said at least zone of the substrate in

  paper before depositing the iridescent ink.

  According to another characteristic, the thickness of the ink deposit

  iridescent in reflectance is greater than four microns.

  According to another characteristic, the grammage of the substrate in

paper is less than 90 g / m2.

  According to another advantageous characteristic, said print is printed

  film using a printer or offset technique.

  According to yet another characteristic, the printing of the ink

  iridescent is produced by screen printing, rotogravure or by size-

  sweet. The subject of the invention is also a printed medium which can be authenticated without any particular instrumentation, characterized in that it comprises, on the same zone, an iridescent ink in reflectance under which is placed a film made up of at least one color ink capable of to be observed in transmittance under the printing of ink

iridescent in reflectance.

  According to yet another characteristic, the support consists

by a paper substrate.

  According to yet another characteristic, the support consists of a first paper substrate on which the film is placed and by a second translucent substrate on which the iridescent ink is placed and in that the second translucent substrate is fixed on the first substrate in paper. According to another characteristic, the iridescent ink partially covers the film, leaving a portion of said film to remain under

shape patterns.

  According to another advantageous characteristic, figurative patterns

  and / or text are placed under the iridescent ink.

  Thus, the authentication of the printed support can be done by any user by illuminating the support with natural light or an electric lamp, the observation of the different colors in transmitance or in reflectance being done respectively by interposing the support printed between the eye and the light source or by placing the printed support next to the light source. Furthermore, the figurative patterns and / or text printed under the iridescent ink are not detectable by the user when observing the support in reflectance, and are therefore not either

photocopiable.

  The invention will be better understood on reading the description which

  will follow accompanied by the drawings in which: - Figures 1 and 2 represent the steps of manufacturing a printed support according to the invention, - Figure 3 shows one of the observation modes of the printed support to control its authentication , - Figures 4 to 6 show the different stages of manufacturing a printed support according to an improved embodiment, - Figure 7 shows another variant of manufacturing the printed support according to the invention, - Figure 8 shows the one of the modes of observation of the printed medium. The manufacture of a printed support according to the present invention

  is carried out as follows.

  First of all, as shown in FIG. 1, a film 3 is made, made up of colored ink, for example black, on an area of the

  support 1 consisting of a sheet of plain paper.

  The production of this film 3 on the sheet of paper 1 can be done using the offset technique or else using a printer or a photocopier, the black ink being one ink

  traditional without any particular property.

  Then, as can be seen in FIG. 2, an iridescent reflectance ink 4 composed of pearlescent pigments having the particularity of reflecting the

  light received like what a mirror would do.

  This ink 4 can optionally be deposited in such a way that it partially covers the film 3, leaving a portion of said film 3 to remain in the form of patterns. These patterns are shown in Figure 2 in a rectangular form but of course they can be

  replaced for all figures such as logos or by text.

  Thus, the first printing of the film 3 can be carried out according to the offset process, while the underlying printing of the iridescent ink 4 in reflectance is necessarily carried out by screen printing, by gravure or by intaglio because of the need depositing a layer of ink 4 whose thickness exceeds five microns so

  to hide the presence of film 3 during the reflectance observation.

  Thus, the reflection color is obtained when the support 1 is placed in such a way that the ink 4 faces a light source. In this case, unlike printing a so-called traditional color ink where the color is obtained by subtractive synthesis, here the user will observe a color by direct reflection on the pearlescent pigments without penetration of light to the support 1 According to another observation mode represented in FIG. 3, the printed support is interposed between a light source and the user in such a way that the iridescent ink 4 in reflectance is placed facing the user. In this observation mode, the transmission color is rendered for the superimposition of the black ink forming the film 3 under the printing of the pearlescent pigments of the ink

4 iridescent in reflectance.

  Therefore, only the black ink forming the film 3 interferes with the light source while the printing of pigments

  pearlescent forming ink 4 remains neutral.

  Thus, by printing by superimposition in the same area of the sheet of paper 1 a black ink deposited by any printing process and then an ink 4 containing pearlescent pigments deposited by screen printing, rotogravure or intaglio, then obtain a means of authentication by observing a diclroic effect in reflected light and another color in light

transmitted.

  It is understood that the film 3 produced during the first printing can be formed by an ink of color different from black, the transmission color observed by interposing the printed medium between the eye of the user and the light source being rendered by the superimposition of the color of traditional ink under the impression of pearlescent pigments

  remaining neutral in this observation mode.

  Likewise, the film 3 may be composed of several colored inks, each colored ink being deposited in a well-defined area of said film 3. In this alternative embodiment, obtaining several underlying color inks combined with a pearly printing gives combinations of colors in reflection and transmission of great complexity, very difficult to reproduce by traditional techniques, resulting in increased security. Several successive underlying prints are also possible in order to strengthen the protection of the printed medium against the risk of counterfeiting. In addition, the inks used must have the quality of not degrading with heat in order to be able to use the printed medium in xerographic or magnetographic printing, if necessary.

  for customizing the printed support according to the present invention.

  According to an improved embodiment, represented in FIGS. 4 to 6, of the method according to the invention, a text 2 is printed on the sheet of paper 1 before depositing the film 3. This text 2 can, well

  understood, to be replaced by all figurative motifs.

  The film 3 is then produced by superimposing it on the text 2 and then depositing the iridescent ink 4 in reflectance also by superposition on the film 3. The ink 4 iridescent in reflectance can also be deposited leaving a portion of the film 3 under

shape patterns.

  In this improved embodiment, it is preferable to use the same color ink to make the text 2 and the film 3. In this case, the text 2 shown in dotted lines in FIG. 5 cannot be visible to the eye naked when the printed support is placed opposite

of a light source.

  Indeed, in this observation mode, the user will only see the reflection color given by the impression of pearlescent pigments as well as the patterns produced by omitting said

  pearlescent pigments on a portion of the film 3.

  Conversely, if the printed medium 1 is interposed between the user and a light source, the text 2 appears in transvision as shown in FIG. 8. In this embodiment, it will be preferable to use inks of dark colors to print text 2 as well as film 3 and also use a sheet of paper 1

  whose grammage is less than 90g / m2.

  Thus, the information contained in the text 2 and perceptible by transfer as a result of colorimetric differences on the printed medium 1, disappears completely on the black and white photocopies and

  on color photocopies, returned uniformly.

  It is understood that it is also possible to first make the film 3 and then to superimpose the text 2 on the film 3 without

depart from the scope of the invention.

  Likewise, it will be possible to make film 3 with several colored inks, each colored ink being deposited in a well-defined area of said film 3 and to print text 2 with the same colored inks, taking care to print the same inks

colors in the same areas.

  According to a manufacturing variant of the printed support shown in FIG. 7, a film 3 ′ and a text 2 ′ are first produced on a sheet of plain paper 1 ′ whose grammage is less than 90 g / m2 and deposited an iridescent reflectance ink 4 on a support

translucent 5.

  This reflective iridescent ink 4 whose area is equal to that of the film 3 may also include patterns by

  omission of pearlescent pigments on the translucent support 5.

  It then suffices to fix the translucent support 5 on the sheet of paper 1 ′, for example by heat-sealing or heat-bonding, in order to obtain a printed support according to the present invention, said printed support then having the same transmittance and

  reflectance as previously exposed.

  Of course, the invention is in no way limited to printing techniques, these being different depending on the inks and the

pigments contained in inks.

Claims (14)

  1. A method of printing a support making it possible to control its authenticity, characterized in that it comprises the following steps: - a film (3) comprising at least one color ink is produced on at least one area of the support , and an ink (4) iridescent in reflectance is deposited by superimposition on said film (3), said colored ink forming the film being such that the film is perceptible in transmittance under the impression of   said reflective iridescent ink.   2. Method according to claim 1, characterized in that the support consists of a paper substrate (1) on which, successively, the film (3) is produced and the ink (4) is deposited 1 5 iridescent.   3. Method according to claim 1, characterized in that the support consists of a first paper substrate (1 ') on which said film is made and by a second translucent substrate (5) on which the iridescent ink is deposited and in that said translucent substrate is fixed on the paper substrate.   4. Method according to any one of the claims   previous, characterized in that the iridescent ink is deposited in such a way that it partially covers the film, allowing it to remain   a portion of said film in the form of patterns.   5. Method according to any one of claims 2 to 4,   characterized in that figurative patterns and / or text (2) are also produced on said at least zone of the paper substrate before deposition iridescent ink.   6. Method according to any one of the claims   previous, characterized in that the thickness of the ink deposit (4)   iridescent is greater than four microns.   7. Method according to any one of claims 2 to 6,   characterized in that the grammage of the paper substrate is less than g / m2.   8. Method according to any one of claims   previous, characterized in that said film is printed using a   printer or offset technique.   9. Method according to any one of the claims   previous, characterized in that the printing of the iridescent ink is   produced by screen printing, rotogravure or intaglio.   10. Printed medium which can be authenticated without any particular instrumentation, characterized in that it comprises, on the same zone, an ink (4) iridescent in reflectance under which is placed a film (3) consisting of at least one color ink capable of to be observed in transmittance under the printing of ink iridescent in reflectance.   11. Printed support according to claim 10, characterized in that   that it consists of a paper substrate (1).   12. Printed support according to claim 10, characterized in that it is constituted by a first paper substrate (1 ') on which the film is arranged and by a second translucent substrate (5) on which is disposed the iridescent ink and in that the second translucent substrate   is attached to the first paper substrate.   13. Printed support according to any one of claims   to 12, characterized in that the iridescent ink partially covers   the film leaving a portion of said film to remain in the form of patterns.   14. Printed support according to any one of the claims   to 13, characterized in that figurative patterns and / or text (2) are arranged in iridescent ink, said figurative patterns and / or text being only detectable by observation in transmittance and therefore not photocopiable.