WO1997010958A1

WO1997010958A1 - Security document and method for its manufacture

Info

Publication number: WO1997010958A1
Application number: PCT/GB1996/002325
Authority: WO
Inventors: Charles Edward Chatwin
Original assignee: De La Rue International Limited
Priority date: 1995-09-20
Filing date: 1996-09-20
Publication date: 1997-03-27
Also published as: AU6995696A; GB9519185D0

Abstract

A security document has a core (1) carrying graphical biometric indicia (24) related to the bearer of the document. The indicia (24) has been printed on the core (1) using one or more inks which are not detectable under visible wavelength illumination.

Description

SECURITY DOCUMENT AND METHOD FOR ITS MANUFACTURE

The invention relates to security documents and methods for their manufacture. Security documents are found in a wide variety of fields and include for example identification cards, credit cards, passports, cheques and the like. There is a continuing need to increase the protection of such documents against counterfeiting and fraud. A method which has been used, particularly in the field of identification cards and passports, is to include biometric data related to the bearer of the document. Such data can include the bearer's signature or fingerprint but often includes a photo-image of the bearer. Typically, the photo-image has been supplied in a conventional manner separate from the remainder of the document and is inserted between a core and cover layer of the document by the document issuer who is usually separated from the manufacturer of the remainder of the document itself. The issuer then secures the photo- image to the core, secures the cover layer over the photo- image, and then issues the document.

It has been found that in some cases, it is possible for the cover layer to be separated from the core thus enabling the photo-image to be removed and replaced by a different photo-image.

An attempt to deal with this in the past has been by making use of a laser printing technique in which the photo-image is written by laser onto the under surface of a cover layer which is then secured to the core. However, this is a complex and an expensive procedure and is also not necessarily as secure since the photo-image is provided on the cover with the remainder of the information printed on the core.

It is also known to provide indicia on the core of the document which is not detectable in the visible wavelength range. Typically, this indicia will be revealed under ultraviolet or infrared radiation and is usually constituted by some image which is common to all security documents in a particular group to enable the image readily to be recognised by someone confirming the authenticity of the document. Although this adds some security to the document, it can be reasonably easily duplicated by counterfeiters. It is also known to allow the bearer to impress his signature onto a security document in such a way that the signature cannot be seen under visible radiation but can be revealed under ultraviolet radiation. The problem with this, however, is that there is little control over who provides the signature which is normally applied after the document has been issued.

In accordance with one aspect of the present invention, a security document having a core carrying graphical biometric indicia related to the bearer of the document is characterised in that the indicia has been printed on the core using one or more inks which are not detectable under visible wavelength illumination.

In accordance with a second aspect of the invention, a method of providing graphical biometric indicia on a core of a security document comprises printing the graphical biometric indicia on the core using one or more inks which are not detectable under visible wavelength illumination.

We have found that for the first time it is now possible to print graphical biometric indicia relating to the bearer of the document directly onto the core of the document. This has not previously been possible due to the difficulties of offset printing onto document cores and in particular the difficulties of offset printing graphical biometric indicia which need to be unique for each document. Furthermore, by printing the graphical biometric indicia using one or more inks which are not detectable under visible wavelength illumination, additional security is achieved since the presence of the indicia is not readily apparent.

A further advantage of the invention is that it enables the cc olete security document to be manufactured centrally, including the biometric indicia, once this biometric data has been supplied to the manufacturer and without the problems associated with adhering individual photo-images and the like to the core. Thus, the manufacturer can be supplied for example with digitised data defining the biometric indicia which can then be processed electronically and at mass production rates. Many of these advantages can also be achieved with non- central manufacture, for example at the point of issue. Preferably, the graphical biometric indicia are printed onto the core using digital offset printing. In this method, the graphical biometric indicia are stored digitally and then used to control operation of an offset printer. However, other printing techniques could be used such as ink jet, laser, electrostatic and dye diffusion transfer providing these can respond to digitally stored graphical biometric indicia and suitable invisible inks, dyes and toners are available.

Thus, in accordance with a third aspect of the present invention, a method of producing a series of security documents, each intended for a different bearer, comprises feeding the core of each document in sequence to a printing machine having a store for storing digital data defining graphical biometric indicia related to the bearer of each document; and causing the printing machine to print the graphical biometric indicia related to each bearer on a respective core using one or more inks which are not detectable under visible wavelength illumination and in response to the respective stored data. It has been found that with digital printing machines currently available, a rate of printing can be achieved equivalent to 18,000 single-side iso-sized plastic cards or 4,000 4 page machine readable passport sections.

Graphical biometric indicia include features such as the bearer's signature, fingerprint and photo-image. The invention is particularly concerned with printing the bearer's photo-image on the core. Typically, the core will also be provided with conventional security printing, and/or a security thread, and/or a watermark. Security printing may include one or more of rainbow printing, guilloches, line patterns and the like. In addition, or alternatively, the core could carry one or more optical variable effect generating structures such as holograms and diffraction gratings. Furthermore, other known security features could be included such as latent images, see-through features and liquid crystal watermark features.

Preferably, the core is not responsive to the radiation at which the or each ink is responsive although in some cases, the core could be coated with a suitable material in the region in which the indicia are printed, the coating not being responsive to the radiation at which the or each ink is detectable. This then enables the indicia to be detected.

The core could be manufactured as a single layer or as a multi-layer laminate and can be made of any conventional core material such as, plastics (e.g. PVC or polycarbonate) , paper or polymeric material such as Teslin (Trade Mark) .

The ink(s) used to print the invisible indicia can be of any known type provided the indicia are not detectable under visible wavelength illumination. Examples include fluorescent inks revealed by the use of ultraviolet light, phosphorescent inks, photochromic inks temporarily revealed by high energy light exposure, thermochromic inks revealed by heating, anti-stokes inks, infrared responsive inks, magnetic inks and coatings.

The inks themselves can respond in the visible or invisible wavelength range and could include taggants.

In some cases, the invisible graphical biometric indicia may be printed using a single ink but in other cases two or more inks could be used to achieve a coloured effect. In these cases, the ink dots would need to be spaced apart and should not overprint any other ink dot in the graphical image.

In simple examples, a single representation of the indicia is printed on the core. However, one or more additional representations of the indicia may be printed, at least one of which is detectable in the visible wavelength range. This may be monochrome or multi¬ coloured. This enables the document readily to be authenticated at a relatively low confidence level if a machine for revealing the normally invisible indicia is not available.

In more complex examples, the invisible graphical biometric indicia could be associated with visible indicia. Furthermore, the invisible graphical biometric indicia could be wholly or partly overprinted on the visible indicia.

In the case of normally visible indicia, these could be printed using any conventional and suitable ink including, for example, metameric inks revealed by the use of a suitable viewing filter such as an infrared filter for a pair of red metameric inks, and chemically responsive inks.

In some cases, a document can consist simply of the core but in most cases the core will be covered with one or more cover layers in the form of self-supporting transparent layers, or lacquer coatings. Such coatings can be applied using silk screen techniques and the like.

Typically, the document will be one of a series of such documents, each document carrying indicia which is identical except for indicia relating to the bearer of the document.

Examples of security documents include passports, visas, vehicle licence certificates, vehicle tax certificates, identity cards, financial transaction cards, access cards, cheques, bonds, tickets, passes, brand protection items, authentication certificates, vouchers, bank notes, credit notes, financial instruments, legal documents, stamps, permits, licences such as driving licences, vehicle tax discs, tickets including lottery tickets and gaming cards, seals such as brand authentication labels and seals, tamper indicating seals and the like.

An example of security documents and a method for their manufacture will now be described with reference to the accompanying drawings, in which:-

Figure 1 is a schematic diagram of an offset printing press; and,

Figure 2 illustrates the indicia printed by the printing press shown in Figure 1.

The invention will be described in connection with the manufacture of pages for identity documents such as passports, the pages being printed in groups of four and then being separated into individual pages for stitching into respective booklets.

The apparatus shown in Figure 1 is provided for offset printing indicia onto individual sheets 1 initially stored in a supply store 2. The sheets 1 are typically of A3 size and are already provided with security indicia such as by intaglio printing, rainbow printing, holograms and the like. The sheets are typically made of paper or polymers such as Teslin (Trade Mark) . The sheets are fed individually via a conveyer system 3 to the nip between an impression roller 4 and a rubber surfaced blanket roller 5 of an offset printing machine 6. The machine 6 also includes an electrostatic imaging drum 7.

Circumferentially spaced around the circumference of the imaging drum 7 are an ink cleaning head 8, a charging head 9, an imaging discharge head 10, and a set of six printing ink sources 11-16.

The respective printing ink sources 11-14 supply yellow, magenta, cyan, and black inks respectively. The source 15 is a source of normally invisible ink such as an ink which fluoresces under ultraviolet illumination. The source 16 is spare but could be used either for a visible or normally invisible ink. In other examples one of the sources could hold a single colour, for example black ink, for printing visible indicia and three or four of the sources could hold different fluorescent inks which generate different colours on UV illumination so as to print a multi-colour fluorescent image. In principle, the six sources can be filled with any combinations of inks provided at least one is normally invisible. In some cases one or more of the visible inks could include additional materials such as a fluorescent material or a taggant.

In a further example, not shown, seven ink sources could be provided, four for holding visible inks and three for holding invisible inks which fluoresce in different colours or UV illumination. This would enable an image to be provided in a full visible colour version and a full colour invisible version.

The invisible ink is typically a toner of the following composition

Organic fluorescent compound 1-20 wt% Liquid carrier 30-67 wt%

Resin binder 5-25 wt%

Charge control agent 5-35 wt%

Dispersing agent 2-10 wt%

The organic fluorescent compound may be any of the compounds described in EP-A-0314350 and can be chosen so as to fluoresce in a chosen colour such as orange, yellow/green, red or blue.

The liquid carrier can be a saturated hydrocarbon such as kerosene. The resin binder may be for example ethylene terpolymer, styrene butadiene, styrene acrylonitrile, polycarbonate, or polyester resin.

The charge control agent may be an azo metal complex such as Cr . The dispersing agent can be a fatty acid amine or amide, for example stearamide. As an alternative to the use of an offset printer, laser printer stations could be provided in sequence past which the sheets 1 are fed, each station printing a different visible or invisible ink. The imaging discharge head 10 is connected to a microprocessor 17 which in turn is connected to a digital data store 18.

An example of a printing machine which can be used with this invention is the Indigo machine manufactured and sold by Indigo B.V.

In operation, a sheet 1 is supplied from the store 2 by the conveyor 3 to the nip between the rollers 4,5 where it is grabbed by a retaining device (not shown) which holds the sheet on the drum 4. At the same time, the microprocessor 17 determines the security documents which are to be printed on the sheet supplied from the store 2 and the bearers of those security documents. Typically, four security documents will be printed on a single sheet 1. The store 18 includes digital data for each colour component (CMYB) of a photo-image of the bearer of each security document and during the supply of the sheet l, the microprocessor 17 accesses digital data defining the yellow component of each of the four photo-images corresponding to the four security documents to be defined by the sheet 1. This digital data is supplied to the imaging discharge head 10 which discharges pixels on the drum 7 in the appropriate manner to define the yellow component of the four photo- images. In addition, the micro-processor 17 activates the appropriate source 11-14, in this case the source 11, so that yellow ink is selectively transferred to the charged pixels on the drum 7. The ink is then carried around, upon clockwise rotation of the drum 7, to the rubber blanket on the roller 5 which is also rotating so that ink is transferred onto the blanket and, upon rotation of the roller 5, onto the core substrate 1 as it passes through the nip between the roller 5 and the roller 4. The substrate 1 is maintained on the roller 4 by the retaining device so that it is brought around and back into the nip between the rollers 4,5. During this rotation, the drum 7 continues to rotate so that any yellow ink remaining on the drum is removed by the cleaning head 8 and the drum is recharged by the head 9 and then the discharge head 10 discharges the drum 7 in accordance with the requirements of the next colour component and the process repeats in the sequence magenta, cyan and black. This process is repeated until all the four visible inks have been overprinted to produce a half-tone visible photo-image.

In addition, the substrate 1 undergoes a further rotation and passage through the nip between the rollers 4,5 during which a monochrome photo-image is printed onto the substrate using the invisible ink supplied to the roller 5 via the roller 7 from the source 15, following selective discharge of pixels at the head 10 in response to obtaining suitable information from the store 18 for the invisible image. Conveniently, the digital data used for the invisible image constitutes the data used for one of the colour components of the visible image. This reduces the storage space required in the store 18.

Following all five rotations, the retaining device is activated to release the printed substrate which is then ejected into a store 19. The operation of the various components shown in Figure 1 is under the control of a master controller (not shown) , typically a microprocessor.

Following printing, the substrate may be coated with a protective lacquer or more than one lacquer and then will be divided into individual documents which can then be stitched into respective passports. The lacquer should not include ultraviolet responsive materials, at least in the region of the invisibly printed photo-image so that the photo-image can be revealed under UV illumination and the lacquer should also not block the spectral response of the biometric data. Similarly, the substrate 1 should also not be ultraviolet responsive. Figures 2A and 2B illustrate an example of a printed substrate which has passed through the printing machine 6 but omitting details of the security printing provided on the substrate prior to printing by the machine 6. For reasons of clarity, the substrate is illustrated in two separate Figures 2A and 2B. The images shown in Figures 2A and 2B are combined on a single substrate in a rectangular array. As can be seen in Figures 2A and 2B, four sets of information are provided 20-23 each corresponding to a separate identity document. The outlines of the documents which are produced from the substrate are indicated at 31. Each set of information 20-23 includes a visible photo- image 30 of the bearer of the passport and a normally invisible image 24 which fluoresces under ultraviolet illumination. For convenience, this normally invisible image 24 has been shown in a visible form. In addition, the information printed includes fixed indicia in black type defining headings for various different types of information as indicated for example at 25 together with information unique to the bearer of a passport such as his name 26, the document number 27, the bearer's date of birth 28 etc. Some of this information is also printed in optical character reader form at 29. All the information shown in Figure 2 will be printed by the printer 6. It will be understood that although the invention is described in connection with the printing of cut sheet, it could also be used for printing continuous, web fed sheet.

Claims

1. A security document having a core carrying graphical biometric indicia related to the bearer of the document characterised in that the indicia has been printed on the core using one or more inks which are not detectable under visible wavelength illumination.

2. A document according to claim 1, wherein the biometric indicia includes one or more of the bearer's signature, fingerprint and photo-image.

3. A document according to claim 1 or claim 2, wherein the core is provided with security printing.

4. A document according to claim 3, wherein the security printing includes one or more of rainbow printing, guilloches, and line patterns.

5. A document according to any of the preceding claims, wherein the core carries one or more optical variable effect generating structures.

6. A document according to any of the preceding claims, wherein the core is formed of paper or Teslin.

7. A document according to any of the preceding claims, wherein the or each ink is chosen from the group comprising fluorescent inks, phosphorescent inks, photochro ic inks, thermochromic inks, anti-stokes inks, infrared responsive inks, magnetic inks, and coatings.

8. A document according to any of the preceding claims, wherein the or each ink responds in the visible wavelength range.

9. A document according to any of the preceding claims, further comprising a second, visible representation of the graphical, biometric indicia printed on the core.

10. A document according to any of the preceding claims, wherein the indicia have been printed using digital offset printing.

11. A document according to any of the preceding claims, further comprising at least one cover layer extending over the core.

12. A document according to claim 11, wherein the cover layer comprises a lacquer coating.

13. A document according to any of the preceding claims, the document being one of a series of such documents, each document carrying indicia which is identical except for indicia relating to the bearer of the document.

14. A document according to any of the preceding claims, the document comprising one of a passport, visa, vehicle licence certificate, vehicle tax certificate, identity card, financial transaction card, access card, cheque, bond, ticket, pass, brand protection item, authentication certificate, voucher, bank note, credit note, financial instrument, legal document, stamp, permit, licence such as driving licence, vehicle tax disc, ticket including lottery ticket and gaming card, seal such as brand authentication label and seal and tamper indicating seal.

15. A method of providing graphical biometric indicia on a core of a security document, the method comprising printing the graphical biometric indicia on the core using one or more inks which are not detectable under visible wavelength illumination.

16. A method according to claim 15, wherein the printing comprises digital offset printing.

17. A method according to claim 15 or claim 16, wherein the core has been provided with security printing and/or a security thread prior to the printing step.

18. A method according to any of claims 15 to 17, adapted to produce a security document according to any of claims 1 to 14.

19. A method of producing a series of security documents, each intended for a different bearer, the method comprising feeding the core of each document in sequence to a printing machine having a store for storing digital data defining graphical biometric indicia related to the bearer of each document; and causing the printing machine to print tb graphical biometric indicia related to each bearer or respective core using one or more inks which are not detectable under visible wavelength illumination and in response to the respective stored data.

20. A method according to claim 19, wherein the digital data defines the ink intensity of each pixel of the indicia.

21. A method according to claim 19 or claim 20, for producing a series of security documents according to any of claims 1 to 14.