CA2053229A1

CA2053229A1 - Secure image production

Info

Publication number: CA2053229A1
Application number: CA002053229A
Authority: CA
Inventors: Edward Stanley Radclyffe
Original assignee: Individual
Current assignee: 3M Co
Priority date: 1989-04-27
Filing date: 1990-04-27
Publication date: 1990-10-28
Also published as: ATE175629T1; EP0737595A3; DE69032896T2; DE69032896D1; EP0470131A1; KR920700932A; LV10596B; DK0470131T3; EP0470131B1; WO1990012694A1; EP0737595A2; KR0134670B1; HK1009949A1; LV10596A; EP0470131A4; AU611340B2; AU5395890A; ES2127185T3; PH26483A

Abstract

Abstract A laminate containing an image is produced by printing the image on a layer of a high temperature glue which has been applied to a layer of a transparent medium. The image is printed on the glue layer using carbon or a carbon-containing compound that does not flow when applied to the glue surface. The combination of transparent medium high temperature glue and image is then bonded to a substrate using a thermal bonding process to produce a laminate of the transparent medium and the substrate. The image is not distorted by the thermal bonding process, but remains clearly visible through the transparent medium. Typically the transparent medium will be a polyester film or a sheet of glass beads dispersed in glue. One or more additional layers may be bonded to the substrate to increase the stiffness of the product laminate.

Description

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.

WO ~/12694 PCT/AU90/00l67 2~322~

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 - 3 _ 2~322~

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.

4 PCr/AU90~OOt6, 2~322~

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, 2~32~

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 ~32?.9 (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 ' W O 90/12694 PCIr/AU90~00167 2~322~

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.

2~322~

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.

. . ` , ~ .

2 ~

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 i32~

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.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:-

1. A method of producing an image within a laminate, characterised by the steps of (a) coating one side of a sheet of transparent medium (10, 20) with a layer (11) of a high temperature glue;
(b) producing an image (12) on the glue layer using carbon or 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 (13) to the high temperature glue layer on which the image has been produced; and (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.

2. A method of producing an image within a laminate, characterised by the steps of (a) producing an image (12) on the glue layer of a first laminate comprising a sheet of a transparent medium (10, 20) to which is bonded a layer (11) of a high temperature glue, 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 carbon-containing compound to set; then (b) applying a substrate (13) 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.

3. A method as defined in claim 1 or claim 2, in which the transparent medium is a sheet (10) of polyester material.

4. A method as defined in claim 1 or claim 2, in which the transparent medium (20) comprises glass beads dispersed in glue.

5. A method as defined in any preceding claim, in which the image is applied to the glue layer by a xerographic process, the carbon or carbon-containing or other radiation absorbent compound being the toner used in the xerographic process.

6. A method as defined in any one of claims 1 to 4, in which the image applied to the glue layer is produced using a programmable printer which prints using a ribbon impregnated with, or carrying a layer of, carbon or a carbon-containing compound.

7. A method as defined in any one of claims 1 to 4, in which the image is applied to the glue layer by a jet printer, the ink of which is the carbon-containing compound.

8. A method as defined in any preceding claim, including the additional step of bonding at least one further layer (27) to the product laminate to increase the stiffness thereof.

9. An image-containing laminate produced by the method of any preceding claim.