A PRINTED SECURITY FEATURE

Abstract

A printed security feature for a security document including a substrate, the security feature comprising: a first functional effect ink printed on a first surface of the substrate, and a second functional effect ink printed on the first and/or a second surface of the substrate, at least partially overlapping the first functional effect ink, wherein the first and the second functional effect inks in combination create an imagery feature which resembles an appearance of a security thread.

Claims

1. A printed security feature for a security document including a substrate, the security feature comprising: a first functional effect ink printed on a first surface of the substrate, and a second functional effect ink printed on the first and/or a second surface of the substrate, at least partially overlapping the first functional effect ink, wherein the first and the second functional effect inks in combination create an imagery appearance which resembles an appearance of a security thread.

2. The security feature according to claim 1, wherein the first functional effect ink is printed as a solid strip, and the second functional effect ink is printed as recognisable patterns.

3. The security feature according to claim 2, wherein the second functional effect ink is printed within boundaries of the solid strip formed by the first functional effect ink, that is, the recognisable patterns are printed such that they substantially overlap with the strip formed by the first functional effect ink, or wherein the second functional effect ink is printed such that it extends beyond boundaries of the solid strip formed by the first functional effect ink, wherein portions of the second functional effect ink which extend beyond the boundaries of the solid strip are configured as a shadow image visible in transmission.

4. (canceled)

5. The security feature according to claim 1, wherein at least one of the first functional effect ink and the second functional effect ink includes a colour switching ink, which displays a variable colour appearance when a viewing condition and/or a viewing angle changes, or wherein at least one of the first functional effect ink and the second functional effect ink includes an ink comprising metallic ink particles, which create a metallic appearance.

6. (canceled)

7. The security feature according to claim 1, further comprising a non-functional effect ink printed on the substrate in one or more ink layers, and on one or both surfaces of the substrate, wherein non-functional effect ink is printed to coat a major area of the first and second surfaces of the substrate, to produce a suitable printing surface for subsequent security features applied to the substrate, and further wherein the non-functional effect ink is optionally omitted in one or more regions where the first and the second functional effect ink have already been applied, wherein within the one or more regions, the security feature displays a glossy surface appearance, and effects of the first and second functional effect inks are perceivable to an observer through the one or more regions where the non-functional effect ink is omitted, wherein outside the one or more regions, the security feature displays a matt appearance, and effects of the first and second functional effect inks are partially concealed by the non-functional effect ink, and wherein the glossy appearance and the matt appearance of the security feature are more easily distinguishable from each other at oblique viewings, and when the security feature is viewed in reflection; wherein the glossy appearance and the matt appearance of the security feature are less distinguishable from each other at non-oblique viewing angles, or when the security feature is viewed in transmission.

8. (canceled)

9. (canceled)

10. (canceled)

11. The security feature according to claim 7, wherein the first and the functional effect inks are both printed on the first surface of the substrate, and the non-functional effect ink is also applied on the first surface of the substrate.

12. The security feature according to claim 7, wherein the non-functional effect ink is applied in one or more ink coating layers, to form a shadow image visible from the second surface of the substrate, wherein the shadow image is observable in reflection, but becomes less observable in transmission, and further wherein the shadow image is formed as a negative shadow image, that is, the non-functional effect ink is omitted in accordance with a design of the shadow image, or the shadow image is formed as a positive shadow image, that is, the non-functional effect ink is printed such that more ink is deposited in areas where the positive shadow image is formed, either by printing additional layers of the non-functional effect ink, or by depositing a higher amount of the non-functional effect ink by adjusting parameters of a printing apparatus.

13. (canceled)

14. The security feature according to claim 7, wherein the substrate is a transparent or translucent substrate made from a polymeric material, or wherein the security document is a polymeric banknote substrate.

15. The security feature according to claim 7, wherein the first and second functional effect ink, and the non-functional effect ink are all applied in an in-line printing process on the same printing apparatus, preferably a gravure printing apparatus including a plurality of printing units, each printing unit arranged to apply a layer of ink before the next layer of ink is applied.

16. The security feature according to claim 1, wherein the security feature is of an elongate configuration which extends a substantial distance, or the entire distance between a first and a second edge of the security document, wherein the first and the second edges are parallel, or wherein the security feature is of an elongate configuration which has a length which is much greater than its width.

17. (canceled)

18. A security feature for a security document including a substrate, the security feature comprising: a first functional effect ink printed on a first surface of the substrate; a second functional effect ink printed on the first and/or a second surface of the substrate, at least partially overlapping the first functional effect ink, and a non-functional effect ink printed in one or more ink layers to create a shadow image which is observable in reflection.

19. The security feature of claim 18, wherein the first and second functional effect inks in combination create an imagery appearance which resembles an appearance of a security thread.

20. The security feature of claim 19, wherein the security feature is of an elongate configuration which extends a substantial distance, or the entire distance between a first and a second edge of the security document, wherein the first and the second edges are parallel, or wherein the elongate configuration has a length which is much greater than its width.

21. (canceled)

22. The security feature of claim 18, wherein the security feature is configured such that it displays a glossy, or a brighter visual appearance in some regions, and a less glossy, or a duller visual appearance in other regions, to resemble the appearance of a security thread which is at least partially embedded in the substate.

23. The security feature of claim 18, wherein the first functional effect ink is printed as a solid strip, and the second functional effect ink is printed as recognisable patterns.

24. The security feature of claim 23, wherein second functional effect ink is printed such that it appears as a second shadow image visible in transmission and visible from both sides of the security document.

25. The security feature of claim 18, wherein at least one of the first functional effect ink and the second functional effect ink includes a colour switching ink, which displays a variable colour appearance when a viewing condition and/or a viewing angle changes, or wherein at least one of the first functional effect ink and the second functional effect ink includes an ink comprising metallic ink particles, which create a metallic appearance; or wherein the first and second functional effect inks may include fluorescent, luminescent, phosphorescent inks, photochromic, thermochromic, hydrochromic, or peizochromic inks.

26. (canceled)

27. (canceled)

28. The security feature of claim 18, wherein the non-functional effect ink is also printed on the substrate in one or more ink layers, and on one or both surfaces of the substrate, and the non-functional effect ink is optionally omitted in one or more regions where the first and the second functional effect ink have already been applied.

29. (canceled)

30. The security feature of claim 28, wherein within the one or more regions, the security feature displays a glossy surface appearance, and effects of the first and second functional effect inks are perceivable to an observer through the one or more regions where the non-functional effect ink is omitted; wherein outside the one or more regions, the security feature displays a matt appearance, and effects of the first and second functional effect inks are partially concealed by the non-functional effect ink, and wherein the glossy appearance and the matt appearance of the security feature are more easily distinguishable from each other at oblique viewings, and when the security feature is viewed in reflection; wherein the glossy appearance and the matt appearance of the security feature are less distinguishable from each other at other viewing angles, such as from non-oblique viewings, or when the security feature is viewed in transmission.

31. (canceled)

32. The security feature of claim 18, wherein the shadow image is formed as a negative shadow image, that is, the non-functional effect ink is omitted in accordance with a design of the shadow image; or the shadow image is formed as a positive shadow image, that is, the non-functional effect ink is printed such that more ink is deposited in areas where the positive shadow image is formed, either by printing additional layers of the non-functional effect ink, or by depositing a higher amount of the non-functional effect ink by adjusting parameters of a printing apparatus.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0105] Preferred embodiments of the invention will now described by way of example with reference to the accompanying drawings in which:

[0106] FIG. 1a is a front view of a printed security feature applied as a security device on a security document, in accordance with a first embodiment of the present disclosure;

[0107] FIG. 1b is shows a transmitted view of the security feature of FIG. 1a;

[0108] FIG. 2 depicts a transmitted view of a security feature applied as a security device on a security document, in accordance with another embodiment of the present disclosure;

[0109] FIG. 3 shows a reflected view of a printed security feature, in accordance with another embodiment of the present disclosure;

[0110] FIG. 4 shows a schematic diagram of a security document comprising a printed security feature in accordance with one embodiment of the present disclosure;

[0111] FIG. 5 shows a schematic diagram of a security document with a printed security feature in accordance with another embodiment of the present disclosure;

[0112] FIG. 6 shows a schematic diagram of a security document with a printed security feature in accordance with yet another embodiment of the present disclosure.

DETAILED DESCRIPTION

[0113] Examples of various visual effects provided by different embodiments of a printed security feature 200 of the present disclosure will now be described with reference to FIGS. 1a, 1b, 2 and 3. Constructions of a printed security feature 200 which are able to generate such visual effects are illustrated in FIGS. 4 to 6.

[0114] In one embodiment, the printed security feature 200 is configured such that it generates an imagery appearance which is similar to that of a conventional foil thread, at least when viewed from one side of a supporting substrate. However, in preferred embodiments, a more complex, dynamic visual appearance and authentication feature is provided by the present security feature 200, as detailed further below. The security feature 200 as disclosed herein is able to be manufactured entirely on a printing apparatus, through sequential printing steps, which eliminates the requirement of additional embedding steps which are generally required when incorporating conventional foil threads in paper based security documents.

[0115] FIG. 1a is a front view of a security feature 200 applied on a substrate of a security document 100, in accordance with one embodiment of the present disclosure. The security feature 200 is configured in the shape of an elongate strip which extends transversely across a width of the security document 100. Preferably, the security feature 200 is arranged to extend a substantial, or the entire width of the security document 100. The width of the security feature is around 3 mm to 12 mm, or more preferably around 5 mm to 10 mm. Although in FIGS. 1a and 1b the security feature 200 is substantially linear and extends straight from a top edge to a bottom edge of the security document 100, it should be appreciated that in other embodiments, the security feature 200 can have elements which extend outwardly from the security feature 200, and the security feature 200 is not restricted to a linear shape.

[0116] With reference to FIG. 1a, when viewed from a first side of the security document in reflection, the security feature 200 displays a dynamic, optically variable visual appearance. For example, the colour appearance of the security feature 200 changes as the viewing angle changes.

[0117] In another embodiment, the security feature 200 may be configured to additionally provide a visible change of a perceived surface texture of the security document. By perceived surface texture it is meant that the security feature 200 displays a change from a glossy surface appearance to a more matt appearance, or vice versa, as the viewing angle changes. For example, in FIG. 1a, portions 211 of the security feature display a more glossy appearance, whereas portions 212 of the security feature 200 display a more matt appearance. As the viewing angle changes, the difference between the matt and glossy appearances of the security feature 200 may become less apparent. FIG. 1b depicts a transmitted view of the security feature 200 of FIG. 1a. When the security feature 200 is viewed in transmission, from the first surface of the security document 100, the matt and glossy appearances of the security feature 200 are less visible, and the security feature 200 generates a more uniform imagery appearance 213 as indicated in FIG. 1b.

[0118] In another embodiment, in addition to the visual effects mentioned above, the security feature 200 is configured to provide a shadow image 220 when the security feature 200 is viewed in transmission, such as that shown in FIG. 2. Depending on the construction of the security feature 200, this shadow image 220 can be configured to be visible in transmission from both sides of the security document 100, or it may be only visible from one side of the security document 100. As seen, the shadow image 220 may be configured to extend beyond boundaries 210 of the security feature 200, thus not being limited by the narrow width of the security feature 200, and allowing more information content or more complex imagery to be embedded in the feature.

[0119] In an alternative embodiment, and in addition to or as an alternative to the visual effects mentioned above, the security feature 200 is configured to provide a shadow image 230 which is visible when the security feature 200 is viewed in reflection, from a second side of the security document 100, such as that shown in FIG. 3. Preferably, the shadow image 230 is only visible, or more visually perceivable, when viewed in reflection, and becomes less apparent, or disappears completely when the thread 200 is viewed in transmission, from either side of the security document 100. Although not illustrated in FIGS. 2 and 3, it will be appreciated that the shadow images 220 and 230 can be formed as multi-tonal shadow images, displaying a tonal variation across its imagery appearance.

[0120] This embodiment, in which the security feature 200 includes a shadow image 230 which is visible in reflection and is less apparent, or disappears completely in transmission, is particularly unusual. Shadow images or watermarks are security features which are known to be more visible in transmission than reflection, whereas this shadow image provides the opposite effect being more visible in reflection. To that end, a security feature according to this embodiment may be employed with greater design freedom than other embodiments described herein and, in particular, does not require to resemble or simulate a security thread or be elongate in nature. This particular embodiment could, for example, be applied as a security feature patch.

[0121] Although a limited number of visual effects are shown as exemplary embodiments in FIGS. 1a to 3, it should be appreciated that various combinations of the colour switching effect, perceived surface texture change effect, and different types of shadow images as described above can be used in different combinations, to produce a desirable security feature that provides a suitable level of authentication.

[0122] Details of how various embodiments of the printed security feature 200 are manufactured will now be described with references to FIGS. 4 to 6.

[0123] FIG. 4 shows a cross-sectional schematic diagram of a security document 100 including a security feature 200, in accordance with a first embodiment of the present disclosure. The security document 100 includes a substrate 203, onto which the printed security feature 200 is applied. It will be appreciated that the substrate 203 can be made from any material appropriate for use as security substrates, such as plastic or polymeric material including but not limited to polypropylene (PP), polyethylene (PE), polycarbonate (PC), polyvinyl chloride (PVC), polyethylene terephthalate (PET), or a composite material of two or more materials, such as a laminate of paper and at least one plastic material, or of two or more polymeric materials. In this embodiment, the substrate 203 is made from biaxially-oriented polypropylene, also known as BOPP.

[0124] In the embodiment shown in FIG. 4, the printed security feature 200 includes a first functional effect ink 201 applied to a lower surface 203b of the substrate 203, and a second functional effect ink 202 which at least partially overlaps with the first functional effect ink 201. The first functional effect ink 201 and the second functional effect ink 202 may be both applied to the same surface of the substrate 203 as shown in FIG. 4, or alternatively, they may be applied to opposite surfaces of the substrate 203, and take advantage of the transparent or translucent nature of the substrate 203, to allow additive colour mixing of the first and second functional effect inks.

[0125] In this embodiment, the first functional effect ink 201 is printed to form recognisable patterns, whereas the second functional effect ink 202 is printed in a more uniform manner and forms a solid strip which determines boundaries 210 of the security feature 210. Preferably, the solid strip serves as a background for the recognisable patterns formed by the first functional effect ink 201. The first and second functional effect inks 201 and 202 can be of different types, or they can be the same type of ink but depicts a different colour appearance. The first functional effect ink 201 may be a colour shifting ink, which displays a colour change when viewed at different angles. The second functional effect ink could be a metallic colour ink, to better simulate the appearance of a foil thread. Preferably, the security feature 200 generates a glossy surface appearance when viewed from the position of viewer 300.

[0126] FIG. 5 shows anther embodiment of a printed security feature 200, which is configured to additionally display a change in a perceived surface texture of the security document 100 as discussed above. Similar to the embodiment show in FIG. 4, a first and a second functional effect ink 201 and 202 are again applied to a lower surface 203b of a substantially transparent substrate 203. However, the security feature 200 also comprises additional ink layers 204a, b, c, d, e of a non-functional effect ink, in order to create a more complex security feature 200.

[0127] On a top surface 203a of the substrate 203, two ink coating layers 204a, 204b of the non-functional effect ink are printed. These two layers are each omitted in selected regions which are indicated by different sized gaps 205, which effectively form one or more half windows for the security substrate 100. Layers 204a and 204b at least partially overlap with the first and second functional effect inks 201 and 202, in order to create the change in perceived surface texture of the security feature 200. On the bottom surface 203b of the substrate 203, three layers 204c, 204d, 204e of non-functional effect ink are applied. Preferably, the non-functional effect ink layers are printed to cover a major area of substrate 203, in order to create a suitable printing surface for subsequent security features which are applied to the security document 100.

[0128] When the security feature 200 of FIG. 5 is viewed in reflection, from the top surface 203a of the substrate 203 and from viewer position 300, an imagery appearance such as the one illustrated in FIG. 1 will be observed. As the non-functional effect ink is printed to overlap partially with first and second functional effect ink 201 and 202 within the boundaries 210, some portions of the first and second functional effect inks 201 and 202 are viewed directly through the substrate 203, whereas other portions of the first and second functional effect inks 201 and 202 are viewed through the non-functional effect ink layers 204a and 204b. When the functional effect inks are viewed through the non-functional effect ink layers, a dull, matt appearance will be observed, whereas when the functional effect ink layers are viewed directly through the transparent substrate 203, via gaps 205, the security feature 200 displays a more glossy surface appearance, and any special effects contributed by the functional effect inks 201 and 202 will be clearly visible. In this way, the same security feature 200 can be configured such that it appears to have different surface texture at different viewing angles.

[0129] In one embodiment, the non-functional effect ink is an opacifying ink, which is typically of a light colour, for example, white, grey, or a tinted blue colour appearance, and is semi-transparent after applied to a printing surface. When the embodiment of FIG. 5 is viewed in transmission, as the non-functional effect ink is semi-transparent, recognisable patterns formed by the first functional effect ink 201 will still be visible, and the difference between matt and glossy appearance of different portions of the thread will become less apparent, such as that shown in FIG. 1b.

[0130] It will be appreciated that printing the non-functional effect ink layers such that they partially overlap with the functional effect ink layers provides further advantages, in addition to its visual appeal. When printing a plurality of ink layers in an in-line printing process, each printed ink layer is subject to a certain printing tolerance. As more and more ink layers are applied, it becomes more difficult to accurately register all the printed ink layers such that they appear identical from one security substrate to another. For example, with the embodiment shown in FIG. 4, although the first and second functional effect ink layers 201 and 202 are shown as in perfect registration with each other, that is, the edges of these two inks are perfectly aligned, in practice it is often the case that the two ink layers are not in perfect registration, thus causing spoilage or causing an inconsistent imagery appearance. The overlapping non-functional effect ink layers 204a, b, c, d, e can help to alleviate such issues, as they are printed to overlap edges of the first and second functional effect inks 201 and 202, thus any potential misregistration between the functional effect ink layers will be concealed. Secondly, as the non-functional effect ink layers can be the same as opacifying ink layers which are applied as base layers before subsequent security features are formed, the manufacturing of the security feature 200 forms part of the initial printing process for the security document, thereby avoiding the need to increase the number of printing steps, which can then lead to an increase in manufacturing costs of the security substrate 100.

[0131] In a further embodiment, the non-functional effect ink layers are configured such that they include gaps both on the top surface 203a and bottom surface 203b of the substate 203, to make the security feature even more visually appealing and complex. For example, the non-functional effect ink layers can be configured to further create a shadow image which is visible in reflection, and when the security feature is viewed from a lower surface of the security document 100. This embodiment is illustrated in FIG. 6.

[0132] In this embodiment, non-functional effect ink layer 204d is printed in accordance with a negative shadow image, that is, the ink layer 204d is selectively omitted in accordance with a desired shadow image pattern, as indicated by gaps 206. Alternatively, the non-functional effect ink layers provided on the bottom surface 203b of the substrate 203 can be configured to form a positive shadow image, that is, a heavier ink loading, or more layers of non-functional effect ink are printed in accordance with a positive shadow image pattern. Thus, the visual appearance of the security feature 200 is made more complex and different to counterfeit by the inclusion of the shadow image, as well as the colour shifting effects of the functional effect ink layers 201 and 202, and a change in the perceived surface texture of the security document 100. It should be appreciated that non-functional effect layers 204c, or 204e, or any combination of the non-functional effect ink layers 204c-204e can also be configured to form a desired shadow image pattern. In addition, a multi-tonal shadow image can be formed by the combination of layers 204c to 204e, if each of the layers is printed in accordance with a portion of an overall tonal image. For example, different sized gaps can be provided in layers 204c to 204e, such that the combined opacity of the layers 204c to 204e varies across an imagery region, and resulting in a tonal variation in the shadow image.

[0133] The shadow image formed on the lower surface 203b is preferably only visible in reflection, and disappears in transmission. This is a particular striking effect as existing shadow images are often produced such that they are clearly visible in transmission, but generally difficult to see when viewed in reflection. In addition, the functional effect ink layers 201 and 202 can form a coloured, or a patterned background for the shadow image, again increasing the difficulty to counterfeit such features. In addition, as the shadow image disappears in transmission, the recognisable patterns formed by the functional effect ink 201 then becomes visible.

[0134] The security feature 200 of the present disclosure comprises printed layers of functional effect inks and non-functional effect inks, which resembles the appearance of a security thread in some embodiments, but is also able to provide more complex and striking visual effects as described above. These types of visual effects were not achievable or considered very difficult to achieve by conventional foil threads.

[0135] In one embodiment, all of the functional and non-functional effect ink layers are printed onto the substrate by an in-line printing apparatus, for example, a gravure printing apparatus including a plurality of printing units each arranged to print a layer of ink onto a printing medium, such as a web of substrate film, as it moves past the plurality of printing units. This eliminates the embedding process which is typically required when incorporating conventional foil threads into paper bank notes.

[0136] Further, the non-functional effect ink layers not only form part of the security feature, but also form a suitable printing surface for subsequently applied security features in some cases. This means the security feature of the present disclosure is effectively formed as a substrate feature, and can thus be manufactured by substrate manufacturers, instead of requiring banknote printers to apply this security feature after a security substrate has already been made, thereby streamlining the process of manufacturing.

[0137] Where any or all of the terms comprise, comprises, comprised or comprising are used in this specification (including the claims) they are to be interpreted as specifying the presence of the stated features, integers, steps or components, but not precluding the presence of one or more other features, integers, steps or components.

[0138] It would be understood that the invention is not limited to the specific embodiments described herein, which are provided by way of example only. Scope of the invention is as defined by the claims appended hereto.