Security substrate with reduced amount of ink

Abstract

A security substrate having ink printed thereon is disclosed, wherein the security substrate comprises: a print region and a waste region, wherein the print region has print areas which contain a higher volume of ink per unit area measured in gram per square meter (gsm) than waste areas in the waste region.

Description

SECURITY SUBSTRATE WITH REDUCED AMOUNT OF INKFIELD

[0001] This invention generally relates to a security substrate and a process for manufacturing a security substrate with a reduced amount of ink.

[0002] The invention is particularly, but not exclusively, applicable to security substrates for use in security documents or tokens such as bank notes or identification documents such as identity cards or passports, and the like, and it will be convenient to describe the invention in relation to that exemplary, non-limiting application.BACKGROUND

[0003] Security documents, such as banknotes, are, typically, produced using a number of different printing processes, each one being completed before the next step is applied. Security documents, and particularly banknotes, are formed from a substrate to which one or more layers of printing are applied and are commonly printed using sheet fed systems, in which the banknote substrate is cut into sheets of a specified size and each sheet is printed in sequence.

[0004] Polymer security substrates, again particularly in the banknote industry, are produced by printing onto a polymer film web. After printing, the web is cut into sheets suitable for use in the sheet-fed systems described above. The sheets are typically provided in 500 sheet reams to a banknote printer but are often stacked prior to printing in a pile of many reams.

[0005] The security substrate sheets, once processed by the sheet fed systems, are cut into banknotes, which includes discarding a border around the sheet. The border is, typically, required to be able to print appropriate registration marks and also to avoid spoilage of the actual banknotes when the sheets are being gripped for movement through the sheet fed system.

[0006] As such, there is an expectation of some waste from these printing and cutting steps, where some of the initial materials are not able to be retained in the final product. Reducing wastage of the various materials used in manufacture is desirable.

[0007] Reference to background art herein is not to be construed as an admission that such art constitutes common general knowledge in Australia or elsewhere.SUMMARY

[0008] In a first aspect of the invention, a security substrate having ink printed thereon is disclosed, wherein the security substrate comprises: a print region and a waste region, wherein the print region has print areas which contain a higher volume of ink per unit area measured in gram per square meter (gsm) than waste areas in the waste region.

[0009] In an embodiment, the security substrate is a polymer substrate.

[0010] In an embodiment, the print areas comprise plain areas.

[0011] In an embodiment, one or more layers of ink are printed onto the security substrate, each of the one or more layers having a thickness.

[0012] In an embodiment, the waste region abuts at least one edge of the print region. In an embodiment, the waste region surrounds the print region.

[0013] In an embodiment, the print areas, in plain areas, contain a higher volume of ink per unit area than the waste areas as a result of a reduced amount of ink being printed in the waste region.

[0014] In an embodiment, at least one of the one or more layers of ink are printed in a reduced design.

[0015] In an embodiment, a reduced design is printed as a layer with areas of the layer reversed out, forming one or more reversed out areas.

[0016] In an embodiment, at least one of the one or more layers of ink are printed as a thinner layer.

[0017] In an embodiment, the reversed out areas form a regular pattern.

[0018] In an embodiment, the reversed out areas form an irregular pattern.

[0019] In one embodiment, the reversed out areas comprise more than 10% of the total area of a layer. In a further embodiment, the reversed out areas comprise more than 50% of the total area of a layer. In a preferred embodiment, the reversed out areas comprise more than 80% of the total area of a layer.

[0020] In an embodiment, a reduced design printed as a layer with more than 80% of the total area reversed out is referred to as a minimal design.

[0021] In an embodiment, more than one of the layers of the substrate have a reduced design in the waste region.

[0022] In an embodiment, the reversed out areas have areas of maximum ink height and areas of reduced ink height.

[0023] In an embodiment, the reduced design over the more than one layer are provided in coordinated layers, such that the total maximum height of the ink in the reduced design in the waste region differs by less than or equal to 2 microns to the total height of the ink in plain areas in the print region.

[0024] In an embodiment, the reduced design is a series of lines. In a further embodiment, the reduced design is a series of dots. In a further embodiment, the reduced design is a series of circles or other geometrical figures. In a further embodiment, the reduced design is a random design. In a further embodiment, the reduced design is one or more lines that forms a frame. In this embodiment, the frame is formed around the print region. In this embodiment, the frame does not touch the edge of the print region.

[0025] In an embodiment, there are one or more reduced designs in a layer.

[0026] In an embodiment, the one or more reduced designs are oriented in the same direction. In a further embodiment, the one or more reduced designs are oriented in the same direction over more than one layer. In a further embodiment, the one or more reduced designs are created by printing one or more layers on top of each other.

[0027] In an embodiment, the one or more reduced designs are oriented in different directions. In an embodiment, the one or more reduced designs are oriented in different directions so that maximum height of ink is achieved in areas where the reduced designs are printed on top of each other.

[0028] In an embodiment, the series of lines, dots, circles or other designs of the reduced design are oriented perpendicular to the print direction of the substrate. In an embodiment, the series of lines, dots, circles or other designs of the reduced design are oriented in parallel to the print direction of the substrate. In a preferred embodiment, the series of lines, dots, circles or other designs of the reduced design are oriented at an angle to the print direction of the substrate.

[0029] In an embodiment, there is a distance (d) in orthogonal direction between areas found within the print region or waste region with a maximum height of the ink.

[0030] In an embodiment, the distance (d) is greater than 0.5 mm. In a preferred embodiment the distance (d) is greater than 1 mm. In a more preferred embodiment, the distance (d) is greater than 2 mm. In a further preferred embodiment, the distance (d) is greater than 4 mm.

[0031] In an embodiment, the waste region comprises one layer of ink which covers more than 80% of the waste areas of the waste region.

[0032] In an embodiment, the waste region comprises two layers of ink which cover more than 80% of the waste areas of the waste region.

[0033] In an embodiment, one of the two layers of ink which cover more than 80% of the waste area of the waste region is applied to the front of the substrate and one of the two layers of ink which cover more than 80% of the waste area of the waste region is applied to the reverse of the substrate.

[0034] In an embodiment, the print region has an edge with one of shaped edges, tonal ranges, or a combination of shaped edges and tonal edges.

[0035] In an embodiment, the security substrate has functional elements applied in the waste region.

[0036] In an embodiment, the functional elements have one of the following features: shaped edges, tonal ranges, or a combination of shaped edges and tonal edges in the waste region.

[0037] In an embodiment, the substrate has a first planar surface opposite a second planar surface. In an embodiment, the reduced design printed on the first surface of the substrate is different from the reduced design printed on the second surface of the substrate.

[0038] In an embodiment, the substrate comprises one or more printed security features. In an embodiment, the one or more printed security features are only present in the print region. In an alternative embodiment, the one or more printed security features are present in the waste region having one or more of the following design features: half-tone print; reduced weight of ink as distance from the print region increases; and / or reduced area of print as distance from the print region increases.

[0039] In an embodiment, the print areas contains in plain areas a higher volume of ink per unit area than the waste region due to the reduction in thickness of the total ink printed in the waste areas when one or more layers are printed in the print region but, due to the print design, are not printed in the waste region.

[0040] In an embodiment, the security substrate includes a polymer substrate.

[0041] In an embodiment, the one or more layers are printed onto the security substrate using Gravure printing.

[0042] In an embodiment, the security substrate includes a plurality of security documents formed thereon. In a preferred embodiment, the security substrate is a banknote substrate. In a preferred embodiment, the security document is a banknote.

[0043] In a second aspect of the invention, a pile of security substrates is disclosed, the pile comprising: a plurality of security substrates according to the first aspect of the invention, creating a pile profile with any two points in the pile profile differing by no more than 10 mm in a pile of 10 reams, i.e. 5000 sheets, of substrate.

[0044] In a third aspect of the invention, a method of producing a security substrate is disclosed, the method comprising the steps of: providing a security substrate to a printing process, the substrate having a first surface and a second surface; printing ink onto the security substrate to form a print region and a waste region, wherein the print region has print areas which contain a higher volume of ink per unit area than waste areas in the waste region.

[0045] In an embodiment, the security substrate is initially in the form of a security substrate web and, after the step of printing ink, is cut into sheets.

[0046] In a fourth aspect of the invention, a method of producing a security document is disclosed, the method comprising the steps of: forming a security substrate according to the third aspect of the present invention; cutting the print region of the security substrate into security documents; and discarding the waste region.

[0047] Further features and advantages of the present disclosure will become apparent from the following detailed description.DEFINITIONSBanknote

[0048] As used herein the term banknote is a reference to all documents of value used in transactions. Banknotes are a special case of security documents, as they are numerous in quantity, are highly transacted and are subjected to high wear. Due to the high wear, solutions appropriate for other security documents are often not appropriate forbanknotes, particularly where adhesion of an element, such as printed ink or a security features, to the banknote substrate is concerned.Security Device or Feature

[0049] As used herein the term security device or feature includes any one of a large number of security devices, elements or features intended to protect the banknote from counterfeiting, copying, alteration or tampering. Security devices or features may be provided in or on the substrate of the banknote or in or on one or more layers applied to the base substrate, and may take a wide variety of forms, such as security threads embedded in layers of the banknote; security inks such as fluorescent, luminescent and phosphorescent inks, metallic inks, iridescent inks, photochromic, thermochromic, hydrochromic or piezochromic inks; printed and embossed features, including relief structures; interference layers; liquid crystal devices; lenses and lenticular structures; optically variable devices (OVDs) such as diffractive devices including diffraction gratings, holograms and diffractive optical elements (DOEs). Printed security features are a subclass of security features which are applied by printing, particularly the security inks mentioned above, but also include particular designs in inks, which otherwise would not be classed as security inks.Substrate

[0050] As used herein, the term substrate, and particularly, security substrate refers to the base material from which a security document or banknote is formed. The base material, unless otherwise specified, is a plastic or polymeric (the two terms being interchangeable) material including but not limited to polypropylene (PP), polyethylene (PE), polycarbonate (PC), polyvinyl chloride (PVC), polyethylene terephthalate (PET) or biaxially-oriented polypropylene (BOPP). The base material may be a polymeric film opacified during manufacture, such as by the addition of titanium dioxide or the creation or air bubbles.Opacifying Lavers

[0051] One or more opacifying layers may be applied to a transparent or translucent substrate to increase the opacity of the security document. An opacifying layer is such that LT<L0, where L0 is the amount of light incident on the document, and LT is the amount of light transmitted through the document. An opacifying layer may comprise any one or more of a variety of opacifying coatings. For example, the opacifying coatings may comprise a pigment, such as titanium dioxide, dispersed within a binder or carrier of heat- activated cross-linkable polymeric material. Alternatively, a substrate of transparentplastic material could be sandwiched between opacifying layers of paper or other partially or substantially opaque material to which indicia may be subsequently printed or otherwise applied.Region

[0052] A region, as used herein, corresponds to an area of a surface of a security document or a substrate. For example, a first region located on a first side of a substrate is a different region to a second region located on a second side of the same substrate, even when the two regions are opposite one another. Two regions can be: opposite, wherein each region is located in the same area of the security document or substrate but on opposite surfaces; partially opposite, wherein one region includes a portion opposite all or a portion of the other region; and non-opposite, wherein the regions are entirely not opposite each other.Print Region

[0053] A print region is an area of a substrate that is meant to be part of the final security document.

[0054] The print region contains one or more print areas and one or more security features. However, this is not an exhaustive list and the print region may contain other elements or even areas with no ink or other features.Waste Region

[0055] A waste region is an area of a substrate that is trimmed and spoiled as part of the production process of the final security document.

[0056] The waste region contains one or more waste areas and one or more functional elements, such as registration marks, identification marks or codes and other print or identification assistance features. However, this is not an exhaustive list and the waste region may contain other elements.Print Areas

[0057] Print areas are areas of the print region that contain ink. Print areas can comprise plain areas.Plain Areas

[0058] Plain areas are areas of a substrate with full coverage of at least one opacification ink(s) on one or both side(s) of the substrate.

[0059] Plain areas typically make up the majority of a polymer security substrate. Plain areas do not include areas with substrate security features, such as shadow images, half windows or vignettes.Waste Areas

[0060] Waste areas are areas of the waste region that do not compromise functional elements. That is, they are areas in the waste region that do not have features which assist during printing or with identification.Functional Elements

[0061] Functional elements are areas in the waste region with reduced or increased coverage of opacification inks for a particular purpose in the production process outside this invention, assist in identification in some way (tracking code, production dates, quality codes, etc.) or are security features from the print region which continue into the waste region (to ensure registration of those features or for other reasons). Functional elements for production processes comprise registration marks, and the like, which assist in orientating and registering a print web or print sheets between print units.Print processes

[0062] There are many different print process types used to print on substrates. As outlined above, for the traditional banknote industry, the typical print process types which are followed are sheet-fed offset and sheet-fed intaglio. That is, substrate is supplied in sheets to an offset print press and then, separately, to an intaglio print press. Other print process types which are commonly found both inside and outside the security industry are letterpress, gravure, flexographic and ink jet. All of these print processes require particular types of substrate supply, print equipment and inks. In general, whilst all print process types can be configured to be fed by a web of substrate, the print process types which can run at the highest speeds, and therefore lowest costs, are flexographic and gravure. As is discussed in greater detail below, intaglio printing can be used generically to cover printing techniques in which an image is incised into a surface and the incised line or sunken area holds the ink for printing. However, in printing, and particularly security printing, a distinction is made between gravure (also known as rotogravure) and intaglio (also known as line intaglio) print process types. The skilled person in the art of security printing would immediately understand that an intaglio print process involves high viscosity ink applied to lines incised into a intaglio print plate which is applied at great pressure to the substrate. Likewise, the skilled person in the art of security printing would immediately understand that a gravure print process refers to lower viscosity inkscaptured from a bath of ink by a cylinder with “cells” engraved in the cylinder and applied to a substrate web. Accordingly, any reference to print units of the same print process type in this specification refers to print units being one of a particular print process, as in the examples given above, as would be readily recognised by a person skilled in the art of security printing.BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Embodiments of the invention will now be described with reference to the accompanying drawings. It is to be understood that the embodiments are given by way of illustration only and the invention is not limited by this illustration. In the drawings:

[0064] Figure 1 is a plan view of a security substrate illustrating a print region and a waste region according to an embodiment of the invention.

[0065] Figure 2 is a cross-sectional side view of a security substrate according to an embodiment of the invention.

[0066] Figure 3 is a front view of a pile illustrating reams of a plurality of security substrate sheets according to an embodiment of the invention.

[0067] Figure 4 is a front view of a profile of a pile of security substrates.

[0068] Figures 5(a) to (c) show cross-sectional views of a security substrate according to various embodiments of the invention.

[0069] Figure 6(a) shows a cut-out view of the security substrate of Figure 1 , illustrating the grip edge according to an embodiment of the invention.

[0070] Figure 6(b) shows a cut-out view of the security substrate of Figure 1 , illustrating different patterns on opposing surfaces of the grip edge according to one embodiment of the invention.

[0071] Figures 7 (a) to (h) show various patterns for the grip edge of the security substrate shown in Figure 1 , according to various embodiments of the invention.

[0072] Figure 8 is a cross-sectional side view of a security substrate according to an embodiment of the invention.

[0073] Figure 9(a) is a top view of the obverses of a security substrate according to an embodiment of the invention.

[0074] Figure 9(b) is a top view of the reverse of a security substrate according to an embodiment of the invention.

[0075] Figure 9(c) is a top view of a security substrate according to an embodiment of the invention.

[0076] Figure 9(d) is a top view of a security substrate according to an embodiment of the invention.

[0077] Figure 10(a) and 10(c) are top views of a security substrate according to an embodiment of the invention with a random area of maximum ink height highlighted.

[0078] Figure 10(b) and 10(d) are top views of a security substrate according to an embodiment of the invention illustrating the four quadrants around a random area of maximum ink height with the four neighbouring areas of maximum ink height highlighted.

[0079] Figure 11 is a plan view of a security substrate according to an embodiment of the invention with an additional security device applied.

[0080] Figure 12(a) to (d) show various patterns for the additional security device in the grip edge of the security substrate shown in Figure 11 , according to various embodiments of the invention. Figure 12(a) shows continuous lines to the grip edge; Figure 12(b) shows a cut off with a hard edge on the security substrate; Figure 12(c) shows a cut off with a shaped edge on the security substrate; and Figure 12(d) shows a cut off with a tonal edge on the security substrate.DETAILED DESCRIPTION

[0081] The invention is particularly, but not exclusively, applicable to security substrates for use in security documents or tokens such as bank notes or identification documents such as Identity cards or passports, which are formed from a substrate to which one or more layers of printing are applied.

[0082] Higher quantities of ink used in the manufacture of security substrates can lead to increased emissions and carbon footprint of the printing operation, as well as unnecessary costs of production due to a lower conversion of the initial materials into the final product. By reducing the amount of ink applied to a substrate while printing, both the costs of production and impact to the environment could be minimised.

[0083] The production of a security substrate for the creation of security documents, such as banknotes, will now be described with reference to the Figures. In other embodiments, a different production process, or a combination of different production processes may be used.Reduction in Ink

[0084] Referring to Figure 1 and Figure 2, a printed sheet 10, in the form of a security substrate, is illustrated according to an embodiment of the present disclosure. The security substrate 10 has straight edges. It has a length (L) of approximately 620 mm and a width (W) of approximately 740 mm (as depicted in Figure 1 ). This provides an sheet area of 0.4588 m2. Depending on the application, the length (L) might vary between 500 and 1500 mm and the width (W) might vary between 600 and 1500 mm. Typical dimensions for security substrates are between 500 and 700 mm in length (L) and between 600 and 820 mm in width (W).

[0085] The security substrate 10 comprises a substrate film 15, a print region 12 and a waste region 14. The print region 12 is formed by printing layers of ink onto a substrate. The print region 12 has straight edges. For a sheet with a length of approximately 620 mm and a width (W) of approximately 740 mm, the print region has a length (!_') of approximately 590 mm and a width (W1) of approximately 720 mm. This provides a security substrate area of 0.4248 m2. The length (L1) of the print region might typically vary between 20 and 50 mm shorter than the length (L) of the sheets and the width (W1) of the print region might typically vary between 10 and 30 mm shorter than the width (W) of the sheet. Measurements outside these typical values might occur on occasions.

[0086] The waste region 14 is formed on at least one edge of the print region 12. In the example of Figure 1 , the waste region 14 surrounds the print region. The waste region 14 is cut from the security substrate 10 during a downstream processing step. Cut tolerances have to be considered when considering the area of the print region 12 and waste region 14. Cut tolerances typically amount to approximately + / - 2 mm and the cut requires to be in the print region 12, to avoid having areas with no print in final security documents.

[0087] Figure 1 shows a grip edge 30 and a tail end 35 of the security substrate 10. The grip edge is where the substrate 10 will be gripped and pulled from a pile of security substrates 20 during downstream processing steps. The tail end 35 is found at the other end of the security substrate 10. The grip edge will be discussed in further detail below.

[0088] The waste region can have a first and a second waste depths (Y1 , Y2) formed at opposing ends of the print region. The embodiment is not limited to this, however, and the waste region may have a first waste depth found at only one end of the print region. The first and second waste depths (Y1 , Y2) may vary in size. However, the first and second waste depths (Y1 , Y2) can be identical.

[0089] In some embodiments, the first waste depth (Y1 ) is found at the grip edge 30 of the security substrate 10 and the second waste depth (Y2) is found at the tail end 35 of the security substrate 10. In the embodiment shown in Figure 1 , the first waste depth (Y1 ) found at the grip edge has a depth of 25 mm. The second waste depth (Y2) found at the tail end 35 has a depth of 15 mm. The first and second waste depths (Y1 , Y2) may vary from 0 to typically 50 mm but waste depths outside this region may occur on occasions. Similarly, the waste region can have a first and a second waste depth (X) formed at least one side of the print region and typically have depths similar to the waste depths Y1 and Y2.

[0090] The waste region 14 also includes functional elements 13 and waste areas 19. In this example, functional elements 13 include registration marks used to align print layers between print units, and a numeric code for tracking the sheet. The waste area 19 includes all of the waste region 14 which is not encompassed by functional elements.

[0091] The print region 12 includes a print area 21 , which can include security features, design features or other features in which at least one of the opacification layers 16 (see Figure 2) are not printed. Plain areas 22 are where all of the opacification layers are printed. In this example, security features 23, in the form of windows or half-windows, are present on the security substrate 10 and are formed by not printing one or more of the opacification layers 16 in the area of the security feature 23.

[0092] Figure 2 is a cross-sectional side view of a printed substrate in the form of a security substrate 10, according to an embodiment of the present disclosure. Figure 2 shows a base substrate 15. The base substrate 15 has a first surface 17, and a second surface 18 opposing the first surface, wherein each surface includes a print region 12 and a waste region 14. The base substrate 15 has a height (SH) of approximately 75pm. The substrate height (SH) might vary between 25pm and 150pm. The substrate may be a polymer substrate sheet, however the invention is not limited to this material.

[0093] During a printing stage, one or more opacification layers 16 are printed onto the base substrate 15. The one or more opacification layers 16 may comprise any one or more of a variety of opacifying coatings. For example, the opacification coatings may comprise a pigment, such as titanium dioxide, dispersed within a binder or carrier of heat- activated cross-linkable polymeric material. An appropriate height range is determined for the coloured ink to be used for printing the opacification layers 16. In the embodiment shown in Figure 2, the opacification layers are of an equal height, however the invention is not limited to that embodiment and the one or more opacification layers 16 may vary inheight. In this example, each opacification layer 16 has a height (Z) of 3pm. Typically, the height of the opacification layers (Z) may vary between 1 pm and 6pm.

[0094] The security substrate 10 has a height (H) of approximately 90pm. The security substrate height (H) is dependent on the one or more of the number of opacification layers 16, and the height and thickness of those opacification layers 16. The security substrate height might vary between 30pm and 180pm.

[0095] The waste region 14 is formed at the edges of the print region 12. Opacification layers 16 are printed in the print region 12. One or more opacification layers 16 are not printed in the waste region 14, or at least are printed at a reduced density in the waste region or area of the waste region, such that a reduced amount of ink is printed in the waste region 14.

[0096] Embodiments of this invention are shown in Figure 1 , 2 and 5(a) to (c), and described below. In the embodiments described, the one or more opacification layers 16 are each printed at an individual print stations. The extent that any single opacification layer 16 extends into the waste region is controlled by pre-defined printing parameters. For example, in a Gravure printing press, the Gravure roller will be provided with a printing pattern which covers a pre-determined area of the sheet 10. If desired, all of the opacification layers 16 could be printed such that they have no or only minimal overlap with the waste region 14 and, therefore, the amount of ink printed in the waste region 14 is minimised. In practice, it is helpful to have at least one opacification layer 16 printed in the waste region 14 to assist with downstream processing.

[0097] The print region 12 includes at least one opacification layer 16 printed onto the first surface of the base substrate 15. Preferably, the print region 12 would include at least one opacification layer 16 printed onto the first surface 17 and second surface 18 of the base substrate 15. The waste region 14 may also include at least one opacification layer 16 printed onto the first surface 17 of the base substrate 15. Optionally, the waste region 14 includes at least one opacification layer 16 printed onto the first surface 17 and second surface 18 of the base substrate 15.

[0098] As a result, the print region 12 contains, on average over the area of the print region, a higher volume of ink per unit area than the waste region 14. In the simplest embodiment, this reduction in ink is achieved by the print region 12 including a higher number of opacification layers 16 than the waste region 14. More specifically, the plain areas of the print region contain on average, over the area of the plain areas, a higher volume of ink per unit area than the waste area.

[0099] The print region 12 may transition to the waste region 14 with an edge that has one of shaped edges, tonal ranges, or a combination of shaped edges and tonal edges.

[0100] An example of a security substrate that uses a polymer base substrate would typically include two to four opacification layers on each surface of the base substrate.

[0101] In an embodiment of the invention, the print region 12 includes at least three opacification layers 16 printed onto the first surface 17 of the base substrate 15 and at least two opacification layers 16 printed onto the second surface 18 of the base substrate 15. In this example, one opacification layer 16 is printed onto the first surface 17 and second surface 18 of the base substrate within the waste region 14.

[0102] In an embodiment of the invention, a reduced volume of ink per unit area in the waste region 14 is achieved by reducing the thickness of the one or more opacification layers 16 printed onto the base substrate 15 in the waste region 14, particularly in waste areas. In this embodiment, there is a first opacification layer 16 printed onto the base substrate 15. One or more subsequent opacification layers 16 are printed onto the base substrate 15 which have a height greater than the first opacification layer. These subsequent opacification layers 16 are printed substantially within the print region 12.

[0103] A reduction in ink within the waste region 14, and particularly the waste areas, can be achieved through any one of the described embodiments or examples. A reduction of ink within the waste region 14, and particularly the waste areas, can also be achieved through any combination of the described embodiments and examples of this disclosure. The above embodiments may result in an estimated 2% to 5% reduction in the opacification ink used, however this is dependent on the design and sheet size used.Pile Profile

[0104] Following the printing stage, sheets of printed security substrates are stacked together in one or more piles. The sheets being stacked in an even and uniform arrangement improves efficiencies during downstream processing.

[0105] Figure 3 illustrates a front view of a pile 20 including a plurality of reams 25, each consisting of 500 sheets. The example depicted in Figure 3 shows a pile 20 containing ten reams 25. In this example, the pile 20 has a height (PH) of approximately 450 mm. The pile height (PH) for a pile of ten reams might vary between 350 mm and 550 mm depending on the thickness of the substrate. Each of the plurality of reams has a height (RH) of approximately 45 mm. The ream height (RH) might vary between 35 mm and 55 mm.

[0106] During a standard printing process, it would be expected that the height of each opacification layer would be substantially planar across the length and width of the security substrate immediately after application (i.e. when the ink is still wet), as well as after the inks have complete dried.

[0107] However, embodiments of this invention can lead to a variation in height across the length or width of the security substrate 10, if not all opacification layers 16 are printed across the whole length and / or width of the security substrate. There may also be the inclusion of other elements, such as a security device, which would affect the height of the security substrate. The security substrate may also have other functional elements applied in the waste region. The functional elements may have one of shaped edges, tonal ranges, or a combination of shaped edges and tonal edges in the waste region.

[0108] In an embodiment, the reduction of opacification layers 16 will reduce the sheet thickness in the waste region by approximately 3pm per layer. If the number of opacification layers is reduced from five to two, there would be a reduction of approximately 9pm. This reduction in thickness of the waste region 14 leads to a pile profile of approximately 45 mm for 10 reams.

[0109] As shown in Figure 4, this leads to a difference in the height of a pile 20 of sheets between the print region 12 and the waste region 14. The example depicted in Figure 4 shows five opacification layers in the print region 12 and two layers in the waste region 14. In this example, the pile height in the print region (PH) is approximately 450 mm while the pile height in the waste region (PH1) is approximately 405 mm.

[0110] A pile with a variable profile can adversely affect the downstream printing processes. Typically, a profile of approximately 5 to 15 mm (highest to lowest position on the pile) is acceptable for a ten ream pile, which equates to a profile difference of around 1 to 3 microns on an individual sheet. Therefore, design changes are desirable to stabilise the profile of a pile of security substrate sheets 20.[0011 1] This can be achieved through stabilising the waste region 14 of each security substrate 10.

[0112] The waste region 14 may be stabilised by a reduced design. A reduced design is printed as a layer with areas of the layer reversed out (or not printed). The reversed out areas may form more than 10% of the total area of a layer, or alternatively, more than 50% of the total area of a layer. Preferably, the reversed out areas form more than 80% of the total area of a layer. A reduced design printed as a layer with more than 80% of the total area reversed out is referred to as a minimal design.

[0113] This minimal design provides a minor amount of ink, potentially in more than one layer, such that the waste region 14 has the necessary height to substantially align with the print region. The reduced or minimal designs over the more than one layer are provided in coordinated layers, such that the total maximum height of the ink in the reduced or minimal design in the waste region differs by less than or equal to 2 microns to the total height of the ink in plain areas in the print region. This is in line with typical substrate specifications for polymer substrate, with the maximum difference between any 2 points of a substrate stack of 10 reams (5,000 sheets) being no more than 10 mm.

[0114] Embodiments showing a variety of minimal designs are depicted in Figures 5(c), 6 (a)-(b) and 7(a) to (h).

[0115] For example, thin lines of ink may be applied across a predetermined distance in the waste region 14. These lines can differ in a variety of parameters, such as the thickness of the lines or the shape they create. In some embodiments, they are straight or angled and placed at a distance (D) apart. The lines may also be placed at various angles relative to the edge in the print direction of the security substrate 10. The invention is not limited to these parameters and any other reduced or minimal design that stabilises the edge of the security substrate will be suitable. For example, dots may be used instead of lines, as shown in Figure 7(e).

[0116] As shown in Figure 6(b), there can be variations between the line patterns and properties between those that are applied on the first surface 17 and the second surface 18. The lines on the first surface 17 are depicted as solid lines and the lines on the second surface 18 are depicted as dashed lines. The design may be symmetrical along the width of the grip edge or on each opposing surface. However, the invention is not limited to this and the design does not need to be symmetrical along either the width of the grip edge nor on each opposing surface. Alternative designs may include a series of dots, circles or a random combination of designs. The design may include one or more lines that forms a frame. The frame is formed around the print region 12. The frame may be printed so the frame does not touch the edge of the print region 12.

[0117] Effective reduced design patterns coordinated over several layers provide sufficient support to avoid a pile profile outside standard specifications and at the same time significantly reduce the amount of ink applied in the waste region.

[0118] Figure 8 shows a cross section through an area with a minimal design in the waste region 14. The minimal design has one or more areas with the maximum height (MHO) of opacification ink applied on the obverse side 40 and one or more areas with a reduced heightof opacification ink applied on the obverse side 41 . There is an average distance (DMO) between areas with maximum height of opacification on the obverse 40. The minimal design also has areas with the maximum height (MHR) of opacification applied on the reverse side 43 and areas with a reduced height of opacification ink applied on the reverse side 42. There is an average distance (DMR) between the areas with maximum height of opacification on the reverse 43.

[0119] Figure 9(a) is a top view of an area with a minimal design in the waste region 14 coordinated over two layers. The first layer with a minimal design is a line pattern shown in dark grey, the second layer with a minimal design a line pattern shown in black. There are a number of areas with a maximum height of opacification ink 40 applied are shown as being the areas where the two line patterns cross. The distance (DMO) is the distance between these crossing points.

[0120] Figure 9(b) is a top view of an area with a minimal design in the waste region 14 over one layer. The minimal design is depicted as a series of line patterns. There are a number of areas with maximum height of opacification ink 43 applied which create the pattern. Areas with a reduced height of opacification ink 42 applied are shown as being the areas between the lines. The distance (DMR) is the distance between the lines.

[0121] Figure 9(c) is a top view of an area with an alternative minimal design in the waste region 14 over one layer. The minimal design is depicted as a dot pattern. The areas with maximum height of opacification ink 43 applied are created by the series of dots that create the pattern. The areas with a reduced height of opacification ink 42 applied are shown as the areas between the dots. The distance (DMR) is the distance between a dot and its closest neighbour.

[0122] Figure 9(d) is a top view of an area with an alternative minimal design in the waste region 14 over one layer. The minimal design is depicted as a dot pattern. The areas with maximum height of opacification ink 43 applied are shown as the dots of the pattern. The areas with a reduced height of opacification ink 42 applied are shown as the areas between the dots. The pattern is strictly aligned in the machine direction (MD) and the cross direction (CD). The distance to the nearest neighbour in cross direction (DMR’) is higher than the distance to the nearest neighbour in machine direction (DMR”).

[0123] Figure 10(a) is a top view of an area with a minimal design in the waste region 14 showing only areas of maximum ink height 40. All the other areas (for example, item 41 ) have a somewhat reduced ink height. One randomly chosen area of maximum ink height 44 is highlighted by a triangle.

[0124] Figure 10(b) is a top view of the same area as Figure 10(a) still with one randomly chosen area of maximum ink height 44 highlighted by a triangle. In addition, the four quadrants in cross direction and machine direction are illustrated to assist with identifying the four closest neighbours with maximum ink height 45 in the four quadrants. The corresponding neighbours 45 are highlighted by a square.

[0125] Figure 10(c) is a top view of an area with an alternative minimal design in the waste region 14 showing only areas of maximum ink height 40. All other areas 41 have a somewhat reduced ink height. A randomly chosen area 44 of maximum ink height is highlighted by a triangle.

[0126] Figure 10(d) is a top view of the same area as Figure 10(c) still with one randomly chosen area of maximum ink height 44 highlighted by a triangle. In addition, the four quadrants in cross direction and machine direction are illustrated to assist with identifying the four closest neighbours with maximum ink height 45 in the four quadrants. The corresponding neighbours 45 are highlighted by a square.Edge Designs

[0127] Figure 11 is a plan view of a security substrate 10 showing the grip edge 30 and a plurality of continuous printed security features 54. The features 54 run down the length of the security substrate 10. In the embodiment shown in Figure 1 1 , the features 54 run from the tail end 35 to the grip edge 30. However, the invention is not limited to this embodiment, and the features 54 can take a variety of lengths and shapes in the waste region 14. Different edge designs are used to minimise ink applied in the waste region 14 and wear of doctor blades used to wipe excess inks from printing cylinders in a gravure printing process, e.g. shaped edges or edges with a tonal gradient. A shaped edge or an edge with a tonal gradient will cause less strain when the doctor blade hits that edge in the wiping process and reduce blade wear. Figure 12(a) to (d) show various patterns for the grip edge of the security substrate 10 shown in Figure 11 , according to various embodiments of the invention. Figure 12(a) shows continuous features 54 that run through the waste region 14 to the edge of the security substrate 10. Such a continuous design means there is no edge to the feature and therefore minimise blade wear but it does not minimise ink consumption. Figure 12(b) shows features 54 which are printed only, or only just encroaching into the waste region 14, in the print region 12. Such a design with a hard edge will minimise ink consumption but the doctor blade will hit a hard edge with every rotation and show accelerated wear. Figure 12(c) shows a features 54 which are printed with a reducing width profile within the waste region 14; and Figure12(d) shows features 54 with a tonal edge in the waste region 14. These designs are favourable compromises between ink consumption and blade wear.

[0128] The one or more security substrates 10 in the pile 20 are divided into a number of rows of columns to produce, as a final product, a plurality of security documents without the waste region 14. The security documents can be banknotes, however the invention is not limited to this. In this embodiment, these security documents are stacked in one or more piles for further downstream processing such as high-speed banknote sorting.

[0129] In this specification, adjectives such as left and right, top and bottom, hot and cold, first and second, and the like may be used to distinguish one element or action from another element or action without necessarily requiring or implying any actual such relationship or order. Where context permits, reference to a component, an integer or step (or the alike) is not to be construed as being limited to only one of that component, integer, or step, but rather could be one or more of that component, integer or step.

[0130] In this specification, the terms ‘comprises’, ‘comprising’, ‘includes’, ‘including’, or similar terms are intended to mean a non-exclusive inclusion, such that a method, system or apparatus that comprises a list of elements does not include those elements solely, but may well include other elements not listed.

[0131] The above description relating to embodiments of the present disclosure is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the disclosure to a single disclosed embodiment. As mentioned above, numerous alternatives and variations to the present disclosure will be apparent to those skilled in the art from the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. The present disclosure is intended to embrace all modifications, alternatives, and variations that have been discussed herein, and other embodiments that fall within the spirit and scope of the above description.Item List:

Claims

Claims:1 . A security substrate having ink printed thereon, the security substrate comprising: a print region and a waste region, wherein the print region has print areas which contain a higher volume of ink per unit area measured in gram per square meter (gsm) than waste areas in the waste region.

2. The security substrate of claim 1 , wherein the security substrate is a polymer substrate.

3. The security substrate of claim 1 or 2, wherein the print areas comprise plain areas.

4. The security substrate of any one of the preceding claims, wherein one or more layers of ink are printed onto the security substrate, each of the one or more layers having a thickness.

5. The security substrate of any one of the preceding claims, wherein the waste region abuts at least one edge of the print region.

6. The security substrate of claim 5, wherein the waste region surrounds the print region.

7. The security substrate of any one of the preceding claims, wherein the print areas, in plain areas, contain a higher volume of ink per unit area than the waste areas as a result of a reduced amount of ink being printed in the waste region.

8. The security substrate of any one of the preceding claims, wherein at least one of the one or more layers of ink in a waste area are printed in a reduced design.

9. The security substrate of any one of the preceding claims, wherein a reduced design is printed as a layer with areas of the layer reversed out in a waste area, forming one or more reversed out areas.

10. The security substrate of any one of the preceding claims, wherein at least one of the one or more layers of ink are printed as a thinner layer in a waste area.11 . The security substrate of claims 9 or 10, wherein the one or more reversed out areas form a regular pattern.

12. The security substrate of claim 9 or claim 10, wherein the one or more reversed out areas form an irregular pattern.

13. The security substrate of any one of the claims 9 to 12, wherein the one or more reversed out areas comprise more than 10% of the total area of a layer in waste area.

14. The security substrate of any one of the claims 9 to 13, wherein the one or more reversed out areas comprise more than 50% of the total area of a layer in a waste area.

15. The security substrate of any one of the claims 9 to 14, wherein the one or more reversed out areas comprise more than 80% of the total area of a layer in a waste area.

16. The security substrate of claim 15, wherein a reduced design printed as a layer with more than 80% of the total area reversed out in a waste area is referred to as a minimal design.

17. The security substrate of any one of claims 8 to 16, wherein more than one of the layers of the substrate have a reduced design in the waste region.

18. The security substrate of any one of claims 9 to 17, wherein the reversed out areas have areas of maximum ink height and areas of reduced ink height.

19. The security substrate of claim 18, wherein the reduced design over the more than one layer are provided in coordinated layers, such that the total maximum height of the ink in the reduced design in the waste region differs by less than or equal to 2 microns to the total height of the ink in plain areas in the print region.

20. The security substrate of any one of claims 8 to 19, wherein the reduced design is a series of lines.21 . The security substrate of any one of claims 8 to 19, the reduced design is a series of dots.

22. The security substrate of any one of claims 8 to 19, wherein the reduced design is a series of circles or other geometrical figures.

23. The security substrate of any one of claims 8 to 19, wherein the reduced design is a random design.

24. The security substrate of any one of claims 8 to 19, wherein the reduced design is one or more lines that forms a frame.

25. The security substrate of claim 24, wherein the frame is formed around the print region.

26. The security substrate of claim 25, wherein the frame does not touch the edge of the print region.

27. The security substrate of any one of claims 8 to 26, wherein there are one or more reduced designs in a layer.

28. The security substrate of claim 27, wherein the one or more reduced designs are oriented in the same direction.

29. The security substrate of claim 27 or 28, wherein the one or more reduced designs are oriented in the same direction over more than one layer.

30. The security substrate of any one of claims 8 to 29, the one or more reduced designs are created by printing one or more layers on top of each other.31 . The security substrate of claim 27, wherein the one or more reduced designs are oriented in different directions.

32. The security substrate of claim 27 or 31 , wherein the one or more reduced designs are oriented in different directions so that maximum height of ink is achieved in areas where the reduced designs are printed on top of each other.

33. The security substrate of claim 27, wherein the series of lines, dots, circles or other designs of the reduced design are oriented perpendicular to the print direction of the substrate.

34. The security substrate of claim 27, wherein the series of lines, dots, circles or other designs of the reduced design are oriented in parallel to the print direction of the substrate.

35. The security substrate of claim 27, wherein the series of lines, dots, circles or other designs of the reduced design are oriented at an angle to the print direction of the substrate.

36. The security substrate of any one of the preceding claims, wherein there is a distance (d) in orthogonal direction between areas found within the print region or waste region with a maximum height of the ink.

37. The security substrate of claim 36, wherein the distance (d) is greater than 0.5 mm.

38. The security substrate of claim 36 or 37, wherein the distance (d) is greater than 1 mm.

39. The security substrate of any one of claims 36 to 38, wherein the distance (d) is greater than 2 mm.

40. The security substrate of any one of claims 36 to 39, wherein the distance (d) is greater than 4 mm.41 . The security substrate of any one of the preceding claims, wherein the waste region comprises one layer of ink which covers more than 80% of the waste areas of the waste region.

42. The security substrate of any one of the preceding claims, wherein the waste region comprises two layers of ink which cover more than 80% of the waste areas of the waste region.

43. The security substrate of claim 42, wherein one of the two layers of ink which cover more than 80% of the waste area of the waste region is applied to the front of the substrate and one of the two layers of ink which cover more than 80% of the waste area of the waste region is applied to the reverse of the substrate.

44. The security substrate of any one of the preceding claims, wherein the print region has an edge with one of shaped edges, tonal ranges, or a combination of shaped edges and tonal edges.

45. The security substrate of any one of the preceding claims, wherein the security substrate has functional elements applied in the waste region.

46. The security substrate of claim 45, wherein the functional elements have one of the following features: shaped edges, tonal ranges, or a combination of shaped edges and tonal edges in the waste region.

47. The security substrate of any one of the preceding claims, wherein the substrate has a first planar surface opposite a second planar surface.

48. The security substrate of any one of the claims 8 to 47, wherein the reduced design printed on the first surface of the substrate is different from the reduced design printed on the second surface of the substrate.

49. The security substrate of any one of the preceding claims, wherein the substrate comprises one or more printed security features.

50. The security substrate of claim 49, wherein the one or more printed security features are only present in the print region.51 . The security substrate of claim 49, wherein the one or more printed security features are present in the waste region having one or more of the following design features: half-tone print; reduced weight of ink as distance from the print region increases; and / or reduced area of print as distance from the print region increases.

52. The security substrate of claim 1 , wherein the print areas contains in plain areas a higher volume of ink per unit area than the waste region due to the reduction in thicknessof the total ink printed in the waste areas when one or more layers are printed in the print region but, due to the print design, are not printed in the waste region.

53. The security substrate of any one of the preceding claims, wherein the security substrate includes a polymer substrate.

54. The security substrate of any one of the preceding claims, wherein the one or more layers are printed onto the security substrate using Gravure printing.

55. The security substrate of any one of the preceding claims, wherein the security substrate includes a plurality of security documents formed thereon.

56. The security substrate of any one of the preceding claims, wherein the security substrate is a banknote substrate.

57. The security substrate of claim 55, wherein the security document is a banknote.

58. A pile of security substates, the pile comprising: a plurality of security substrates, each security substrate in the form of any one of claims 1 to 57, creating a pile profile with any two points in the pile profile differing by no more than 10 mm in a pile of 10 reams, i.e. 5000 sheets, of substrate.

59. A method of producing a security substrate, the method comprising the steps of: providing a security substrate to a printing process, the substrate having a first surface and a second surface; printing ink onto the security substrate to form a print region and a waste region, wherein the print region has print areas which contain a higher volume of ink per unit area than waste areas in the waste region.

60. The method of claim 59, wherein the security substrate is initially in the form of a security substrate web and, after the step of printing ink, is cut into sheets.61 . A method of producing a security document, the method comprising the steps of: forming a security substrate using the method of claims 59 and 60; cutting the print region of the security substrate into security documents; and discarding the waste region.

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