Note: Descriptions are shown in the official language in which they were submitted.
W090/t2694 PCT/AU90/0016~
2~3229
TITLE: "SECURE IMAGE PRODUCTION"
Technical Field
This invention concerns the production of security
documents, such as passports, identity cards,
5 identification badges and labels, driving licences
and the like. More particularly, it concerns a
technique for providing, wi~hin a laminated
structure, a printed image that is significantly more
secure than images obtained by conventional
10 procedures.
Back~round
The mo~t common method of producing identity cards,
identification badges and the like involves the steps
of (i) mounting a photograph on a backing sheet of
15 li.ght card, tii) sandwiching the card (with the
photograph attached) between two sheets of a
tran~parent plastics material, then (iii) bonding
(using heat) the transparent sheets together at their
edges. Such cards and badges, however, do not
20 possess the degree of ~ecurity that is required for
passports and for passes to regions containing secret
and classified information, for it is possible to cut
the cards and badges near the edges of the
transparent ~heets, remove the card, substitute a new
25 photograph, and then ~eal the modified card between
two new sheets of transparent plastics material.
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-- 2
Passports are still produced by a technique which
involves bonding a photograph to a page of the
passport, using a conventional paper glue, then
covering at least part of that page (with the
S photograph affixed) with either a tran~parent strip
of a polyester material having adhesive on one side
or a glass bead laminate. In this way the photograph
is covered by the transparent strip or the glass
beads and its security is improved. ~owever, it is
10 possible for a determined person to separate the
components of the passport page, then substitute a
fresh photograph for the photograph that has been
mounted in the passport using this technique.
To improve the security of passports and identity
15 cards, it has been proposed to print photographic
information (including an image of the holder of the
passport or identity card) on the end sheet of a
passport or on a sheet of card, rather than simply
mount photographs on the sheets, and to cover the
20 printed image to prevent the deliberate (or
inadvertent) removal of that information. ~owe~er,
no reasonably economic and technically viable
technique for implementing ~his approach has been put
forward.
25 Disclosure of the Present Invention
It is an object of the present invention to provide a
technique for producing an image within a laminate
formed by a layer of a transparent medium and a sheet
of paper, card or the like, which satisfies the
WO90/12694 PCT/AU90/0016/
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requirements for the production of more secure
passports, identity cards, security badges,
identification labels and the like.
This objective is achievable using the surprising
S discovery that an image can be produced on (or in) a
layer of a high temperature glue (that is, a glue
having a mel~ing point of about 95C) at low
temperature, and that image is not destroyed, if the
toner or other carbon-containing material used to
lO create the image has set, when the glue layer is
heated to create a bond. Thus, if a sheet of a
transparent medium (for example, a polyester material
or a layer of glass beads) has one side coated with a
high temperature glue, and an image is printed on the
15 glue layer using (for example) a laser xerography
technique or printing ink, and that transparent
material is sub~equently bonded to a sheet of paper
or other sub~trate by a thermal process, the image is
presented without deterioration within the laminate
20 thus produced, provided the toner or ink used for the
printing of the image has set on the glue before the
thermal bonding is effected. When the image includes
printing, that printing is machine readable.
~ t has also been found that compounds other than
25 carbon or carbon-containing compounds can be used to
produce machine-readable characters, pr~vided those
other compounds are highly absorbent of radiation
having a wavelength in the visible spectrum or the
near infra-red region.
WO90/12694 PCr/AU90~OOt6,
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Accordingly, the present invention provides a method
of producing an image within a laminate which
comprises the steps of
(a) coating one side of a sheet of transparent
medium with a layer of a high temperature glue;
~b) producing an image on the glue layer using
carbon or a carbon-containing or other radiation
absorbent compound which does not flow when
applied to the glue layer and, if necessary,
allowing or causing the image-producing compound
to set;
(c) applying a substrate to the high temperature
glue layer on which the image has been produced;
and
15 (d) bonding the transparent medium to the substrate
using a known high temperature thermal bonding
process, thus producing a laminate of the
transparent material and the substrate.
Some manufacturers produce a laminate in the form of
20 a sheet of a transparent medium to which a layer of a
high temperature glue has been applied. Such a
product can be used in the present invention, which
then comprises the ~teps of
(a) producing an image on the glue layer of a first
laminate comprising a sheet of a transparent
medium to which is bonded a layer of a high
temperature glue, using carbon or a
carbon-containing or o~her radiation absorbent
oompound which does not flow when applied to the
W O 90/12694 PCT/AU90/0016,
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glue layer and, if necessary, allowing or
causinq the carbon-containing compound to set;
then
~b) applying a substrate to the high temperature
glue layer on which the image has been printed;
and
(c) bonding the transparent medium to the substrate
using a known high temperature thermal bonding
process, thus producing a second laminate within
which the image has been included.
The thermal bonding technique for high temperature
glues - that is, the bonding technique of step (d) of
the first recitation above of the method of the
present invention and step (c) of the second
15 recitation of the present invention in the last
preceding paragraph - is well known, so that detailed
discussion of that technique in this specification is
not necessary.
Since, in almost all uses of the present invention,
20 the image (which may consist of or include printing)
will be viewed through the transparent ~edium, the
image will normally be printed on the glue as a
reverse image.
~ithout limiting the generality of the
25 carbon-containing or radiation absorbing compounds
that may be used in the present invention, the image
may be created by laser xerography or other
photo-copying technique, by an in~-jet printer
WO 90tl2694 PCT/hU90/00167
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-- 6
(provided the ink used is chosen - or thickened - so
that it does not flow on contact with the glue
layer), by a dot matrix printer using a typewriter
ribbon (preferably a carbon typewriter ribbon), or by
5 a typewriter adapted to print mirror images of the
normal characters of the typewriter. Ink jet
printers and dot matrix printers can be used to
create the equivalent of photographic images by an
appropriate printing of dots. The printing of the
10 image is effected by programming the printer after
scanning the image to determine the density of dots
in the pixels which make up the image. Clearly, if a
typewriter ribbon is the medium through which the
carbon or carbon-containing compound is applied to
15 the glue layer, there is no requirement to allow or
cause the material of the image to set before
proceeding to the thermal bonding step of the present
invention.
If a pro~rammable printer is used for the
20 image-producing step of the present invention, an
entire page of a passport, or an entire
identification card or badge, comprising both a
photographic image and lettering, may be printed by
the printer.
25 If the printer used to produce the lettering cannot
also produce a photographic image, then the passport
page or identification card or badge may be produced
with two printing steps. ~he first printing step
will produce an image of the required lettering and
'
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the second printing step will provide the
photographic image of the bearer of the passport or
the holder of the identification card or badge~ ~Of
course, the image may be printed hefore the
5 lettering.) The glue layer containing the two
printed images will then be brought into contact with
the substrate, and the high temperature thermal
process will be used to produce the completed
passport page or identification card or badge.
10 The transparent sheet material is typically either a
flexible, transparent polyester material, such as the
material marketed under the trade mark "Mylar", or it
may be a layer of qlass beads in glue. Both such
materials are available commercially with a layer of
lS high temperature glue applied to one face of the
transparent sheet.
If greater stiffness of the final product laminate is
required, one or more additional layers of any
suitable material may be bonded to the substrate of
20 the product laminate of the pre~ent invention,
preferably ~but not necessarily) using the high
temperature glue bonding technique.
Embodiments of the present invention will now be
described, by way of example only, with reference to
25 the accompanying drawings.
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-- 8 --
srief Description of t ~ s
Figure l is a sectional view ~partly schematic)
through a sheet of transparent polyester material
that is to be bonded to a backing sheet, using glue
5 on which an image has been printed.
Pigure 2 is a similar sectional view (partly
schematic) through a sheet of a glass bead laminate
with a high temperature glue layer, that is being
bonded to a substrate.
lO Detailed Description of the Illustrated Embodiment
Figure l shows a sheet lO of a transparent polyester
material, such as "Mylar" (trade mark), or another
known flexible, tran-cparent polyester material that
i9 available in sheet form, to one side of which a
lS thin layer ll of a known high temperature glue has
been applied by the manufacturer. Thin layers of the
high temperature glue are also transparent.
Figure 2 depicts a glass bead laminate comprising a
layer 20 of glass beads in glue, to one side of which
20 a thin layer ll of a high temperature glue has been
applied. An ~ptional ~but usually present) sheet 26
of backing paper is included to improve the stiffness
of the laminate and to protect the glass beads at the
face of layer 21.
25 In each case, images - u~ually reverse images of a
photographic impre~sion and associated lettering to
be viewed, sub~eqently, through the transparent sheet
WO90/l2694 PCT/AU90/00167
2~22~
lO or 20 in the direction of the arrow A - are
printed on the region 12 of the glue 11, using carbon
or a carbon-containing compound. As indicated above,
laser xerography is a convenient way of producing the
5 images. This way of producing the images is
preferred, but it is acknowledged that increased use
of scanners and programmed printers, and developments
in that technology, may result in programmable
printers becoming the preferred equipment for the
10 image production.
If, as in the example shown in the drawings, the
images are in part lettering, the image of the
lettering may be applied to the glue layer before, or
after, the application of an image of a photographic
15 impression.
When the image is produced by a xerographic process
or with printing ink, the toner must be allowed (or
cau~ed) to set, or the ink must be dry, before the
next step in the fabrication of the product laminate
20 is taken. The setting or drying usually takes a very
short time. Indeed, when laser xerography is used
produce the image, the heat required to set the toner
is applied as part of the printinq process.
Surprisingly, although the heat applied to set the
25 toner should be sufficient to melt the high
temperature glue, the glue layer 11 is not softened
during its passage through the printer.
. . ` , ~ .
WO90/12694 PCT/AU90/00167
2 ~
-- 10 --
When the toner of the image has set, or the ink used
for printing the image has dried, the transparent
sheet 10 or 20 is placed on a substrate 13 of paper
or other suitable material with the glue layer 11
5 sandwiched between the transparent sheet 10 or 20 and
the substrate 13. The substrate 13 may have
information printed on it in regions 14 outside the
area of the -~ubstrate which is covered by the image
regions 12 of the glue layer 11.
10 The sandwich of sheet 10 or 20 with the substrate 13
is then heat treated in the conventional manner to
bond the transparent sheet 10 or 20 to the substrate
13 and form a product laminate of the two sheets.
Following this step it is very difficult to separate
lS the sheet 10 (or 20) from the substrate 13. The
surprising aspect of such a thermal treatment (during
which the temperature of the components of the
sandwich reaches at least about 45C to enable the
high temperature glue layer 11 to bond the sheet 10
20 or 20 and the substrate 13 together) is that the
imprinted image on or in the glue is not destroyed or
distorted, but retains its identity and clarity,
despite the melting of the glue during the high
temperature bonding treatment.
25 After the heat treatment step, the substrate 13 of
the product laminate may be bonded to additional
sheets 27 of paper or card or other suita~le material
to form a thicker, and therefore stiffer, laminate.
It has been found that su~h additional bonding does
W090~12694 PCT/A~90/00167
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not destroy or distort the original image on the
region 12 of the basic laminate. Indeed, tests using
images produced by the present invention have shown
that when the images include alpha-numeric
5 characters, those characters remain machine readable
to the extent required by the International Civil
Aviation Organisation'R specification No 93n3. Thus
the present invention incorporates a stable
machine-readability feature into passports and other
10 travel documents.
If the glass bead laminate of Figure 2 is used, the
protective backing sheet 26 is peeled off the product
laminate after its formation, to expose the outer
surface of the transparent layer 20.
15 It will be appreciated that using the technique of
the present invention, it is possible to produce
identity cards, passport pages, security passes,
identification labels and the like, which are both
durable and significantly more secure than those
20 products made using the methods currently in use.
Those skilled in this field will acknowledge that
although ~wo specific realisations of the present
invention have been illustrated and described above,
modifications to the described embodiments can be
25 made without departing from the present inventive
concept.
