Title of Invention

"A SAFET OF SAFETY PAPER "

Abstract The invention relates to a sheet of safety paper comprising transparent or translucent zones of substantially zero opacity. According to the invention, the sheet (1) is constituted by at least one layer of paper comprising at least one zone (3, 3a_, 3b) of zero thickness and at least one band (4) of transparent or translucent matter coated in the layer of paper so that the band of transparent matter is opposite the zone of zero thi.ckness. The invention is more particularly applicable to papers for bank notes and papers for cheques.
Full Text The present invention relates to a sheet of safety paper comprising at least one transparent zone of substantially zero
opacity having an area of at least 0.2 cm2.and a process for the
preparation of Such Safety paper.
In " the present specification, the term ."paper" is
understood to mean any sheet obtained by the wet method employing a suspension of fibers of natural cellulose and/or of synthetic fibers able to contain various fillers and various additives currently used in paper-making.
Papers which have been rendered transparent are already known in the prior art. Such papers are for exam-ple rendered transparent by chemical compositions (cf. in particular French Patent No. 82 05124, filed on 15th March 1982 by ARJOMARI-PRIOUX). Such papers are rendered transparent over the whole of their surface and are intended for applications in industrial drawings, reproduction of plans, etc...
Chemical processes for partial "transparentization", i.e. at determined places, are also known- Such processes use compositions based on inorganic or vegetable grease or oil which are deposited by printing. However, it is difficult to print on these zones rendered transparent with the aid of present conventional printing techniques (offset, line-engraving, heliography, etc...).
Furthermore, it is known to produce differences in thickness and in density in the paper, particularly by the watermark technique used for rendering safe, paper for bank notes, identity documents or official and va-luable documents. Such watermarks are obtained during manufacture of the sheet of paper by round forms compri-sing intaglio and/or relief impressions or with the aid of water-marking rollers comprising intaglio and/or relief designs associated with a flat table (Fourdrinier mac-
hine). An image is then obtained which, when the sheet of paper is observed by transmitted light, appears either light, if the water-marking roller comprises a design in relief, or dark if the watermarking roller comprises a recessed design. The light zones are due to the fact that the thickness of the sheet and the density of the fibers are less than the thickness of the sheet and the density of the fibers in the zones where there has not been an impression by the water-marking roller. On the contrary, the dark zones are due to the fact that the thickness of the sheet and the density of the fibers are greater.
Such water-marks comprise light parts which generally have areas of some mm2 and the variation in opacity bet-ween the light part of the water-mark and the paper having no water-mark is small. If it is desired to make a print on the light zones of these water-marks, it is very diffi-cult to make the light zones and the print correspond and, even with a very precise locating of the water-marks, it is difficult to obtain a good correspondence.
European Patent Application No. 388 090, filed on 9th March 1990 by DE LA RUE COMPANY pic, describes a safety paper comprising zones of reduced opacity, at determined and well-localized places, the zones making it possible to see by transmitted light, with the naked eye, prints made on the face opposite the face on which the paper is observed. The zones may for example be made in water-mark form by employing processes employing round form or by water-marking rollers.
European Patent Application No. EP-A-549 384 filed by Applicants and published on 30th June 1993, describes a process for manufacturing a sheet of papec comprising at least one zone having a reduced thickness with respect to the thickness of the rest of the sheet, and having an area of at least 0.4 cm2, by disposing on a cloth,
embossed or not, possibly disposed on a round form, an aqueous dispersion containing at least cellulosic fibers, draining the water to form the sheet, in the presence, or not, of a water-marking roller, and drying. Flexible pieces are used which are associated with the watermarking cloth, the water-marking roller or the round form, so that draining of the water during formation of the sheet in the zones of the flexible pieces is reduced with respect to the draining of the water in the zones not comprising a flexible piece.
The sheet of paper obtained in accordance with this process is such that the zone having a reduced thickness has a thickness less by up to 40% than the thickness of the rest of the sheet. The sheet may also be such that said zone has a mean opacity less by up to 40% than the opacity of the rest of the sheet.
French Patent Application No. 93 02373 filed by Applicants on 2nd March 1993 describes another process for manufacturing a sheet of paper comprising at least one region having a reduced thickness with respect to the thickness of the rest of the sheet, characterized in that:
a first layer of paper is formed on a cloth of a first wet part of a paper-making machine,
- a second layer of paper is formed on a cloth of
a second wet part of a paper-making machine,
- one of the two layers of paper presenting at least
local regions of reduced thickness, so that the thickness
of the two layers of paper in said regions is up to 80%
with respect to the thickness of the rest of the sheet,
- the two layers are joined and are dried.
One or even two layers of paper may be produced without problem so as to be locally very thin, at least one of the layers of paper in one region being locally reduced so that the overall thickness of the two layers
is sufficiently reduced to obtain a good transparency.
The sheets of paper obtained by the processes des-cribed in the prior-art documents are used either so as to see in transparency prints made on the face opposite the face on which the paper is observed, this latter face likewise comprising prints which are complementary to the first prints. The sheets of papec may also be used to avoid the scratching of inscriptions made on the region of reduced thickness.
Furthermore, bank notes are known which are constitu-ted by sheets of transparent synthetic material on which a print is made on both sides, the print being such that it leaves a completely transparent zone. A hologram is transferred onto this transparent zone. However, such synthetic notes present drawbacks. They are little resis-tant to manipulation and circulation as the print may be fragile on the plastic. This is why paper notes are preferred, but, at the same time, it is desired to produce a zone which is as transparent as possible. Now, accor-ding to the process described in document EP-A-549 384, the zone obtained is of reduced thickness and of reduced opacity, but a zone of even more reduced opacity is de-sired. According to document FR 93 02373, a sheet of paper with a zone of even more reduced opacity is ob-tained. However, this opacity is still very far from a substantially zero opacity. It has therefore been thought to reduce the thickness of the. zones of reduced opacity further. However, in that case, holes are made in the paper. Consequently, one problem which is raised is that of producing in the paper a virtually transparent zone without piercing the paper in this zone.
Another problem which is raised is that of producing in the paper a virtually transparent zone, which zone may be printed and/or which may receive a hologram or another distinctive or safety mark.
This zone must therefore be sufficiently resistant to support the transfer of a safety mark.
Patent Application WO 94/00225 filed by Applicants on 1st March 1994 describes a sheet of safety paper com-prising at least one zone of reduced opacity, i.e. a zone having a uniform mean opacity less by at least about 40% with respect to the opacity of the rest of the sheet, the zone having an area of at least 0.4 cm2 and the zone having a reduced opacity due to the reduction of its thickness with respect to the thickness of the rest of the sheet and due to the fact that it has undergone an additional "transparentization".
The sheet according to that Application may comprise in a part of the zone of reduced opacity a hologram, an iridescent coating, a print using conventional inks or inks containing coloured pigments, fluorescent , lumi-nescent pigments, photochromic, piezo-optical, piezo-chromic compounds.
The sheet of paper may be a mono-jet sheet, i.e. a sheet comprising a zone whose thickness is not zero, the residual thickness being rendered transparent by chemical means.
The sheet oil paper may be a bi-jet sheet, i.e. it is constituted by a first jet comprising a zone whose thickness is zero and by a second jet rendered partially or totally transparent. In the case of the second jet being rendered totally transparent, this jet may be ob-tained by the tracing paper technique, namely from a suspension of very refined cellulose fibers, in order to obtain the transparency. In the case of the second jet being rendered partially transparent, it is rendered transparent by chemical means in a zone which comes into register with the zone of zero thickness of the first jet.
Such a sheet of paper comprises a zone transparent
in transmitted light, this zone being of large surface. If a, for example, iridescent layer is deposited on the transparent zone, this layer covering the transparent zone only partially, an additional visual effect will be had. Moreover, such a sheet will be very difficult to reproduce by colour photocopier as the iridescent zone will not be reproduced by copying and the transparent zone will be opaque after copying.
However, it is desired to improve the transparency of the zones further. Now, as the transparency is ob-tained, on the one hand, by reduction of the thickness of the sheet and/or by decrease in the density of the cellulose fibers, and, on the other hand, by rendering transparent by chemical means, a transparency sufficient to avoid counterfeiting will not be attained. In fact, if another safety element such as an iridescent layer or a hologram is not deposited on the transparent zone obtained according to this document, a counterfeiter may attempt, after having reproduced the note by colour photocopier, to render transparent the zone rendered opaque by copying.
Document G8-A-1 604 453 describes a safety paper which comprises a fine safety element, namely a narrow band or a thread coated in a sheet of paper. Such a thread has a maximum width of 1 to 1.5 mm. The paper is a paper formed by one layer and it may comprise holes on one face or on the two faces- As the thread has a small width, the holes have a small area. In this way, if a metal or plastic thread is used, due to the small width of the thread and the small area of the holes, it will be difficult to print the thread by prints visible to the naked eye.
Now, one object of the invention is to provide a sheet of safety paper comprising printable transparent zones of which the area is greater than 0.2 cm2. However,
such a sheet raises technical problems. In fact, a ribbon or a band must be introduced, whose width is greater than 5 mm and preferably 20 mm. Now, during manufacture of the sheet of paper, a sheet is formed from an aqueous suspension of cellulose fibers, is drained and dried. Between the wet part and the dry part, the sheet of paper undergoes an elongation. Such elongation may be effected in the machine direction and/or in the cross direction. It may be of about 3%.
Consequently, one problem is to introduce the wide band without it turning or twisting or without it breaking.
Document EP-A-0 059 056 (Indian patent application no. 95/Del/82, granted as 157644) describes the introduction of a thread in a sheet of paper so that the thread is visible on one or both faces of the sheet.
There again, it is question of a paper made from one layer, or mono-jet paper, and the thread is of, small width.
The purpose of the present invention is therefore to provide a sheet of safety paper comprising at least one printable, transparent or translucid zone, this zone having a substantially zero opacity and having an area of at least 0.2 cm2. The sheet is constituted by two layers of paper, the first layer comprising at least one zone of zero thickness and the second layer comprising at least one zone of zero thickness, each zone of the first layer being exactly opposite each zone of the second layer, at least one band of printable, transparent or translucid matter being coated in the layer of paper so that the band of transparent matter is opposite the zone or zones of zero thickness, the width L of the trans-parent band being greater than the largest width 1 of the zones in order to avoid a discontinuity of the sheet.
An essential feature of the invention is that the band of transparent matter is such that its elongation
in the longitudinal and transverse di rection is compa-tible with the elongation of the sheet of paper, machine direction and cross direction, during manufacture thereof.
According to one embodiment of the invention, the band of transparent matter is a band of synthetic matter, for example polyester. According to another embodiment, the band of synthetic matter is completely coated in the sheet of paper in those places which are- not opposite the zones of zero thickness.
The band of transparent matter has a width of at least 5 mm and preferably 20 mm.
However, the sheet of paper may also be made so that the band is alternately coated in the sheet of paper in those places which are not opposite the zones of zero thickness and appears on the surface thereof. Finally, the band of synthetic matter may comprise metallic prints, magnetic prints, holograms and any other safety element.
The invention also relates to a process for manufac-turing the sheet according to the invention.
The process according to the invention consists in making a first layer of paper on a round form from an aqueous suspension of cellulose fibers; making a second layer of paper on a second round form, zones of zero thickness being respectively made on the first and second layer, by means of embossings of the cloths of round forms, said round forms being perfectly synchronized so that the zones of zero thickness of the first layer come perfectly opposite the zones of zero thickness of the second layer; introducing between the layers a band of transparent matter; joining the two layers, and drying them.
Accordingly, the present provides for a sheet of safety paper comprising at least one transparent or translucid zone of substantially zero opacity, having an area of at least 0.2 cm2, characterized in that the sheet (1) is constituted by two layers of paper (2, 5), the first layer (2) comprising at least one zone (3, 3a, 3b) of zero thickness and the second layer (5) comprising at least one zone (6, 6a, 6b) of zero thickness, each zone (3, 3a, 3b) of the first layer being exactly opposite each zone (6, 6a, 6b) of the second layer, by at least one band (4) of printable, transparent or translucid matter coated in the layer (2, 5) of paper so that the band (4) of transparent matter is opposite the zone or zones (3, 3a, 3b) of zero thickness, the width L of the transparent band (4) being greater than the largest width I of the zones in order to avoid a discontinuity of the sheet (1).
The present invention also provides for a process for manufacturing a sheet as described hereinbefore, characterized in that, it comprises:
making a first layer of paper (2) on a round form (16) from an aqueous suspension of cellulose fibers; making a second layer of paper (5) on a second round form (17), zones of zero thickness being made respectively on the first and second layer (2, 5) by means of embossings of the cloths of round forms, said round forms (16, 17) being perfectly synchronized for the zones of zero thickness of the first layer to come perfectly opposite the zones of zero thickness of the second layer; introducing between the layers (2, 5) a band (4) of transparent matter; joining the two layers (2, 5); and drying them.
The sheet of safety paper is not a product of chemical reaction. The product prepared by the process in question is the result of physical phenomena based on refractive indexes of products.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS The following description with references to the accompanying drawings, given by way of non-limiting examples, will enable the invention to be better understood.
Figure 1 is a view in section of a sheet of safety
Paper according to the invention.
Figure 2 is another embodiment of the sheet according to the invention.
Figure 3 is a plan view of a sheet according to the invention.
Figure 4 is a schematic view of a device for making the sheet according to the invention.
Referring now to the drawings, the sheet 1 shown in Figure 1 is constituted by a layer of paper 2 which comprises zones 3, 3a_, 3b of zero thickness and a band 4 of transparent or translucid matter partially coated in the layer of paper 2.
The band 4 is opposite the zones of zero thickness 3, 3a, 3b, as may be seen in Figure 3. The sheet of paper 1 further comprises a second layer of paper 5 which pre-sents zones 6, 6a_, 6b of zero thickness.
Zones 3, 3a, 3b are respectively opposite zones 6, 6a_, 6b.
Thus, if the sheet is observed in transparency in the direction of arrow F (Figure 1) a completely trans-parent zone will be seen, this zone being formed by the zones of zero thickness and by the transparent band. The transparent band 4 may for example be a band of poly-ester. This band is 20 mm wide and the zones have a maxi-mum width of 17 mm. In fact, the band may zigzag by more or less 3 mm with respect to the zones of zero thickness. If the zone is a circle, its radius will therefore be .580 mm and its area about 2.26 cm2. It will therefore be understood that a problem which is particularly diffi-cult to solve is that of making a zone 3 of layer 2 and a zone 6 of layer 5 come exactly into register.
Figure 2 shows another e mbodiment of the sheet accor-ding to the invention. The layer of paper 7 comprises zones 9, 9a of zero thickness, the layer of paper 8 com-prises zones 10, lOa, 10b of zero thickness, only zones
9, 9a being opposite zones 10, lOb. Thus, part of the zones of zero thickness of the first layer 7 is located opposite zones of zero thickness of the second layer of paper 8. By transparency, where zones 9, 10 and 9a, lOb are opposite one another, the observer will see transparent zones 11, 12 (cf. Figure 3), the band 4 of synthetic matter being invisible outside the transparent zones 11, 12, a.3 it is completely coated in the sheet of paper.
It may also be provided that the band be located at certain places on the surface of at least one layer, as shown at 13 in Figures 2 and 3. The band will in that case be visible by reflection.
Tf safety elements are placed on the band 4 at the places provided to be located on the surface of the thread, these safety elements will then be seen with the naked eye.
Safety elements may also be placed on the band 4 at the places where the zones of zero thickness will not be in register.
Figures 2 and 3 show a band 4, layers 7 and 8 and safety elements 14, 15 such that the sheet comprises both transparent zonas 11, 12, safety elements 14, 15 visible either on one face of the sheet of paper or on the other face. The transparent zones, the surface parts with or without safety element, may be alternated, depen-ding on the desired criteria.
The transparent zone (11, 12) may also comprise transferred safety elements.
Of course, the width L of the transparent band 4 must be greater than the largest width 1 of the transpa-rent zones in order to avoid a discontinuity of the sheet 1.
Finally, the safety elements may be of any type, for example prints employing conventional inks or inks containing coloured pigments, fluorescent, luminescent
pigments, photochromic, piezo-optical, piezo-chromic compounds.
The sheet 1 may be manufactured with a device which essentially corresponds to conventional paper-making machines available on the market, which comprise at least two separate wet parts. The device shown in Figure 4 is constituted by a combination of two wet parts with round form 16 and 17 of a so-called double round form paper-making machine. In the wet part of form 16 is made a first layer of paper 2 which is directed towards the wet part of the form 17, being suspended below the pick-up felt. In the second wet part of form 17 is made a second layer of paper 5. A band of transparent matter is Intro-duced between the layers 2 and 5. The two layers of paper are joined at the level of roller 18 and are then dried.
The zones of zero thickness are made by embossings of the cloths of the round forms (16, 17), such embossings being sufficiently thick in order to totally prevent the deposit of the fibers at certain places.
According to the invention, two exactly identical round forms are used and they are synchronized by mechani-cal coupling of their shaft in rotation. Such synchronism is effected by a mechanical coupling well known in the art.
For making the two layers of paper, two installations with round form are preferably used. However, it is also possible to produce the two layers of paper in installa-tions with a flat table, or, for making the two layers of paper, a combination of a flat-table installation and of a round-form installation may be used. In that case, the installations must be synchronized so that the zones of zero thickness of one layer come opposite the zones of zero thickness of the other layer.



WE CLAIM:
1. A sheet of safety paper comprising at least one transparent or
translucid zone of substantially zero opacity, having an area of at
least 0.2 cm2, characterized in that the sheet (1) is constituted by two
layers of paper (2, 5), the first layer (2) comprising at least one zone (3,
3a, 3b) of zero thickness and the second layer (5) comprising at least
one zone (6, 6a, 6b) of zero thickness, each zone (3, 3a, 3b) of the first
layer being exactly opposite each zone (6, 6a, 6b) of the second layer,
by at least one band (4) of printable, transparent or translucid matter
coated in the layer (2, 5) of paper so that the band (4) of transparent
matter is opposite the zone or zones (3, 3a, 3b) of zero thickness, the
width L of the transparent band (4) being greater than the largest
width 1 of the zones in order to avoid a discontinuity of the sheet (1).
2. A sheet as claimed in claim 1, wherein the said band (4) of
transparent matter is a band at least 5 mm wide, preferably 20 mm
wide.
3. A sheet as claimed in claims 1 and 2, wherein the said band of
transparent matter is such that its elongation is compatible with the
elongation of the sheet of paper during formation thereof.
4. A sheet as claimed in any one of the preceding claims, wherein the
said band (4) of synthetic matter is completely coated in the sheet of

paper in those places which are not opposite the zones of said zero thickness.
5. A sheet as claimed in any one of the preceding claims, wherein the
said band (4) is alternately coated in the sheet of paper (1) in those
places which are not opposite the zones of zero thickness and appears
(13) on the surface thereof.
6. A sheet as claimed in any one of the preceding claims, wherein the
said band of transparent matter may comprise metallic prints,
magnetic prints, holograms, iridescent pigments and any other safety
element.
7. A process for manufacturing a sheet as claimed in any one of the
preceding claims, characterized in that, it comprises:
making a first layer of paper (2) on a round form (16) from an aqueous
suspension of cellulose fibers;
making a second layer of paper (5) on a second round form (17), zones
of zero thickness being made respectively on the first and second layer
(2, 5) by means of embossings of the cloths of round forms, said
round forms (16, 17) being perfectly synchronized for the zones of zero
thickness of the first layer to come perfectly opposite the zones of zero
thickness of the second layer;
introducing between the layers (2, 5) a band (4) of transparent matter;
joining the two layers (2, 5); and

drying them.
8. A sheet of safety paper substantially as herein described with
reference to and as illustrated in the accompanying drawings.
9. A process for manufacturing a sheet of safety paper substantially as
herein described with reference to and as illustrated in the
accompanying drawings.

Documents:

1208-del-1994-abstract.pdf

1208-del-1994-claims.pdf

1208-del-1994-correspondence-others.pdf

1208-del-1994-correspondence-po.pdf

1208-del-1994-description (complete).pdf

1208-del-1994-drawings.pdf

1208-del-1994-form-1.pdf

1208-del-1994-form-13.pdf

1208-del-1994-form-2.pdf

1208-del-1994-form-3.pdf

1208-del-1994-form-4.pdf

1208-del-1994-form-9.pdf

1208-del-1994-form-gpa.pdf

1208-del-1994-petition-other.pdf


Patent Number 190611
Indian Patent Application Number 1208/DEL/1994
PG Journal Number 31/2009
Publication Date 31-Jul-2009
Grant Date 15-Mar-2004
Date of Filing 26-Sep-1994
Name of Patentee ARJO WIGGINS S.A.
Applicant Address 3 RUE DU PONT DE LODI, 75006 PARIS, FRANCE.
Inventors:
# Inventor's Name Inventor's Address
1 JEAN-PAUL MENEZ 18 RUE D'ANTONY, 91370 VERRIERES LE BUISSON, FRANCE.
2 PIERRE DOUBLET 1 RUE DE LA LAITERIE, 77160 SAINT-BRICE, FRANCE.
3 PIERRE DOUBLET 1 RUE DE LA LAITERIE, 77160 SAINT-BRICE, FRANCE.
4 JEAN-PAUL MENEZ 18 RUE D'ANTONY, 91370 VERRIERES LE BUISSON, FRANCE.
5 PIERRE DOUBLET 1 RUE DE LA LAITERIE, 77160 SAINT-BRICE, FRANCE.
6 JEAN-PAUL MENEZ 18 RUE D'ANTONY, 91370 VERRIERES LE BUISSON, FRANCE.
PCT International Classification Number D21H 5/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 93 11486 1993-09-28 France