A SECURITY STRIP AND SECURITY PAPER INCORPORATING SAID STRIP

BANDE DE SECURITE ET PAPIER DE SECURITE INTEGRANT LADITE BANDE

English Abstract

A security strip (1) consisting of sectors in which the background is non-
continuous so that it is more difficult to duplicate by optical means than a
continuous background, thereby making the strip harder to counterfeit. The non-
continuous background consists of a dot pattern (2) printed using conventional
printing techniques on an area (3) in which the repeated absence of dots
defines a symbol (4), wherein the dots (2) of the pattern are geometrically
and dimensionally distributed in such a way that they cannot be seen by the
naked eye because the gap (3) between the dots cannot be discerned and the
background appears to be continuous.

French Abstract

La bande de sécurité (1) est constituée de secteurs comportant un fond discontinu plus difficile à reproduire par des supports optiques, qu'un fond continu, de manière à rendre difficile sa falsification. Le fond discontinu se compose d'une trame de points (2) imprimables sur un espace (3) au moyen de techniques d'impression classiques, et dans laquelle l'absence répétée de points définit un symbole (4), dès lors que les points (2) de la trame sont répartis géométriquement et dimensionnellement de sorte qu'ils ne soient pas visibles à simple vue, c'est à dire dès lors que l'espace (3) entre les points simulant un fond continu ne peut pas être évalué.

Claims

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CLAIMS
1.- A security strip (1) that can be inserted in a paper forming a security
document characterised in that it is formed by sectors in which a
discontinuous background consisting in a pattern of points (2) defined upon a
space (3) is observed, wherein the repeated absence of points defines a
symbol (4), it being foreseen that:
- ~the points (2) of the pattern are distributed in lines according to a
concentration comprised between 30 and 200 lines per centimetre,
within the usual screen angles.
- ~the minimum distance between the centres of the points (2) that are
distributed on a same diagonal is comprised between 10 and 270
microns,
such that the points (2) cannot be distinguished and the space (3) between
the points is barely noticeable to the naked eye.
2.- A security strip according to claim 1, characterised in that the points
(2)
forming the pattern are made in a material chosen from fluorescent,
phosphorescent, luminescent and magnetic.
3.- A security strip according to claim 1, characterised in that the space (3)
is
formed in a material chosen from fluorescent, phosphorescent, luminescent
and magnetic.
4.- A security strip according to claim 1, characterised in that the points
(2)
forming the pattern and the space (3) are formed in a material chosen from
fluorescent, phosphorescent, luminescent and magnetic.
5.- A security paper incorporating a security band that can be obtained
according to the characteristics described in claims 1 to 4.

Description

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A SECURITY STRIP AND SECURITY PAPER INCORPORATING SAID
STRIP
DESCRIPTION
OBJECT OF THE INVENTION
The present invention refers to a security strip obtained by
conventional printing means at a reduced cost, as well as to the security
paper, such as legal tender banknotes, a bank cheque, or another type of
document incorporating said security strip.
It is the object of the invention to obtain a security strip the
background of which is formed by a discontinuous pattern of points that is
difficult to reproduce by optical means in order to make it difficult to
forge.
It is also the object of the invention that the pattern of points is
obtained in a simple manner according to a specific geometrical and
dimensional distribution and such that the background seems to be
continuous to the naked eye.
BACKGROUND OF THE INVENTION
A common technique in security paper manufacture is the
insertion of a fine strip of material, such as polyester, that is used as a
security strip those embedded in the paper in order to make forging of the
security document difficult.
Patent of invention US 4 652 015 proposes a procedure to
incorporate a security strip in the security paper used for banknotes and
bank cheques, a strip that is formed such that the characters on the strip can

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only be read by means of transmitted light and are not visible under reflected
light.
This security strip consists of polyester sheet coated by an
aluminium sheet on which the characters are printed by means of a caustic
soda resistant ink, such that the surface on which the characters have not
been reflected gives off when in contact with caustic soda, the characters
then remaining slightly in relief.
In the event of these characters being large they may be visible
under reflected light and could therefore be imitated by a forger using
printing techniques with certain links, which although not perfect could
deceive the general public. The optical effect caused by the metallic
characters is not easy to reproduce; however, since the characters occupied
a small space within the strip a defect in the imitation can go unnoticed.
Known as an evolution in the techniques used to make forgery
more difficult is the security paper proposed in patent of invention EP 0 319
157, comprising a waterproof security strip consisting of a metal sheet on at
least one of its two sides with metal-free portions consisting in repeating
marks, words or designs. In contrast to the patent described above, the
metal surface constitutes the background and there is therefore a greater
continuous metal surface, which makes its reproduction noticeably more
difficult, even more due to the fact that there are no printing means that may
imitate the contrast provided by a continuous metallic strip when the
document is examined with reflected or transmitted light.
One of the problems associated to printing techniques in order to
achieve continuous metallisation of the strip consists in the fact that they
are
not easily accessible to manufacturers and the printing is very slow, on the
other hand another problem relates to the incorporation of fluorescent

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elements being extraordinarily complicated if the metal part of the security
strip is continuous and dark.
DESCRIPTION OF THE INVENTION
The invention proposed consists in the security strip or band
obtained at low cost by means of conventional printing techniques that
produce a discontinuous background configured by a pattern of points that is
hardly noticeable to the naked eye but that observed with suitable magnifying
means allows distinguishing the characteristics thereof, as well as the object
of the invention being the security paper incorporating said strip.
The pattern of points on the security strip will usually constitute the
background of the letters or signs incorporated on the strip, letters or signs
that will be formed thereon by the absence of points.
One of the advantages derived from the present invention refers to
the configuration of the background being by means of a discontinuous
pattern instead of a continuous background, which makes it more difficult to
reproduce by optical means, thus obtaining greater security.
Similarly, the configuration of the background by means of a
pattern allows incorporating fluorescent, phosphorescent, luminescent,
magnetic and other elements either in the points and/or in the space
between the points, or the area of the points can be distinguished from the
space by the use of fluorescent materials in different colours.
Using simple printing techniques it is possible to achieve the
discontinuous pattern of points with the features described regarding the
difficulty of forging, at the same time as simulating a background that seems
continuous to the naked eye.

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For this reason the pattern of points will have a distribution of the
points forming it according to a series of geometric characteristics detailed
below:
The points will be distributed in lines determining a screen ruling
comprised between 30 and 200 lines per centimetre, within the usual screen
angles.
The minimum space between the centres of the points that are
distributed on a same diagonal is comprised between 10 and 270 microns.
DESCRIPTION OF THE DRAWINGS
In order to complement the description being made and to aid
towards a better comprehension of the features of the invention, according to
our preferred practical embodiment, we incorporate as an integral part of
said description a set of drawings that are illustrative and not limiting in
nature, and represent the following:
Figure 1.- Shows an enlarged view of the section of the security
strip for a banknote showing the background formed by a discontinuous
pattern of points where the absence of points forms a symbol.
PREFERRED EMBODIMENT OF THE INVENTION
The security strip (1) object of this invention, as observed in Figure
1, is made up of sectors with a discontinuous background consisting in a
pattern of points (2) defined upon a space (3) where the repeated absence
of points defines a symbol (4), it being foreseen that the points (2) of the
pattern are distributed geometrically and dimensionally so that they are not

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visible to the naked eye, that is, that the space (3) between the points is
barely noticeable.
In this sense, according to that mentioned above, it is considered
that the points (2) are distributed in lines with a concentration comprised
between 30 and 200 lines per centimetre.
Similarly, the distance a, represented in the Figure, corresponding
to the distance between the centres of the points (2) that are distributed on
a
same diagonal is comprised between 10 and 270 microns.
According to this distribution of the points (2) forming the pattern, it
is contemplated that the material of the points (2) can have features of
fluorescence, phosphorescence or magnetism and that the material of the
space (3) does not have that feature, or the other way around, or similarly
there is the possibility that the material of the points (2) is fluorescent
and the
material of the space (3) is also fluorescent, but in different colours. On
the
other hand, the combination of materials with phosphorescence or
magnetism features for the points (2) and for the space (3) is also
contemplated.
The security strip thus formed with the features described can be
incorporated on a paper, such as a banknote, a bank check all others, in
order to thus provide it with security properties that make it difficult to
forge.

Representative Drawing