Patent Application
20100218693
The invention relates generally to instant lottery tickets and specifically to a method of manufacturing instant lottery tickets having graphic overprints applied by offset lithography.
Instant lottery tickets are typically comprised of a substrate having a secure area and a graphic area, with variable game data printed in the secure area and hidden by one or more opaque scratch-off layers printed there over. The colour graphical images that are printed over the scratch-off layers are commonly referred to as graphic overprints. The scratch-off layers and any other layers provided between the variable game data and the graphic overprints are commonly referred to as non-graphic overprints.
The graphic overprints of instant lottery tickets have, heretofore, typically been the least appealing visual element of the tickets because the coatings used to create opacity and scratchability in the scratch-off layers covering the variable game data have been incompatible with lithographic printing processes that produce high quality visual images. This disadvantage presents a significant problem to the instant lottery ticket industry as instant lottery tickets are impulse purchase items and the overall aesthetic appeal of an instant lottery ticket affects its marketability.
Since the inception of instant lottery tickets in the early 1970's, manufacturers have used gravure and flexographic printing processes for the application of graphic overprints because these processes use low viscosity liquid inks that can be readily applied over a wide range of surfaces including typical scratch-off layers. Although the gravure process generates a higher quality visual image than flexography, the cost of a gravure printing cylinder is comparatively high and the print quality tends to degrade unless the printing surface is smooth. Although flexography generates a comparatively poorer quality image (the flexographic printing plate being essentially a rubber stamp), flexographic plates take less time and cost to produce and are suitable for printing on irregular surfaces. Accordingly, instant lottery ticket manufacturers have almost universally adopted flexography for the overprinting of instant lottery tickets.
Innovation by manufacturers of instant lottery tickets in the United States to improve the security and performance of lottery ticket overprints has generally focussed on the formulation of the flexographic overprint coatings and inks. For example, U.S. Pat. No. 4,726,608 issued 23 Feb., 1988 concerns a tamper resistant scratch-off opaque coating, while U.S. Pat. No. 5,569,512 issued 29 Oct., 1996 concerns integrated flexographic overprinting. Although some experimentation with gravure, flexography, letterpress and silkscreen printing methodologies has been proposed (see e.g. U.S. Pat. No. 5,569,512 issued 29 Oct., 1996), no attempt has been made to seek the advantages provided by offset lithographic overprints due to the incompatibility of scratch-off print layers with the lithographic printing process.
Offset lithography provides at least the following advantages relative to other print technologies including gravure and flexography:
Therefore, a method of manufacturing an instant lottery ticket having a graphic overprint applied by offset lithography represents a significant advance in the art of instant lottery ticket manufacturing.
An understanding of the invention will be obtained from the following description of a preferred embodiment thereof, with reference to the following drawings in which:
Where appropriate, identical reference numerals have been used to designate like elements in the figures.
The invention claimed herein provides a method of manufacturing an instant lottery ticket with a graphic overprint applied by offset lithography and the instant lottery ticket made accordingly. Although the relative advantages of offset lithography are many, its use for graphic overprinting of instant lottery tickets has heretofore not been successfully used. The inventor has identified a number of obstacles which must be overcome in order to do so, including a requirement of a smoother printing surface relative to flexography, the high tack of the offset inks which tend to pick the non-graphic overprint and the pH control requirements of the offset dampening solution. Moreover, the inventor has overcome these obstacles by providing a ticket surface, including the surface over the scratch-off layers, which is compatible with offset lithographic printing, thus enabling the printing of an integrated graphic overprint over the entire surface of the ticket.
In accordance with one aspect of the invention, there is provided herein a method of manufacturing an improved instant lottery ticket having a graphic overprint applied by offset lithography. The method comprises applying variable game data in a secure area of a substrate, applying a non-graphic overprint over the variable game data and applying a graphic overprint over a print surface of the non-graphic overprint by offset lithography. The non-graphic overprint has an opaque scratch-off layer and is composed of non-graphic overprint materials. The non-graphic overprint materials render the print surface compatible with offset lithography and resistant to the removal of pH-altering elements therefrom by the application of the graphic overprint. The non-graphic overprint has a thinness and a smoothness, and is sufficiently thin and smooth to resist tacking caused by the application of the graphic overprint.
In accordance with another aspect of the present invention, there is provided herein an improved instant lottery ticket having a graphic overprint applied by offset lithography. The ticket comprises variable game data in a secure area of a substrate, a non-graphic overprint over the variable game data and a graphic overprint applied by offset lithography over a print surface of the non-graphic overprint. The non-graphic overprint has an opaque scratch-off layer and is composed of non-graphic overprint materials. The non-graphic overprint materials and the non-graphic overprint are compatible with offset lithographic printing thereover.
In accordance with a further aspect of the invention, there is provided herein a method of manufacturing an improved instant lottery white ticket suitable for the application thereon of a graphic overprint by offset lithography. The method comprises applying variable game data in a secure area of a substrate and applying a non-graphic overprint over the variable game data. The non-graphic overprint has an opaque scratch-off layer and a print surface, and is composed of non-graphic overprint materials. The non-graphic overprint materials render the print surface compatible with offset lithography and resistant to the removal of pH-altering elements therefrom by the application of the graphic overprint. The non-graphic overprint has a thinness and a smoothness, and is sufficiently thin and smooth to resist tacking caused by the application of the graphic overprint.
In accordance with a further aspect of the invention, there is provided herein an improved instant lottery white ticket suitable for the application thereon of a graphic overprint by offset lithography. The white ticket comprises variable game data in a secure area of a substrate and a non-graphic overprint over the variable game data. The non-graphic overprint has a print surface and an opaque scratch-off layer, and is composed of non-graphic overprint materials. The print surface is configured to receive the graphic overprint. The non-graphic overprint materials render the print surface compatible with offset lithography and resistant to the removal of pH-altering elements therefrom by the application of the graphic overprint. The non-graphic overprint has a thinness and a smoothness, and is sufficiently thin and smooth to resist tacking caused by the application of the graphic overprint.
An exemplary instant lottery ticket 10 with a graphic overprint applied by offset lithography manufactured is shown in
A description of the offset lithographic printing process and of the above-mentioned obstacles follows with reference to
The obstacles to using offset lithography for graphic overprinting of a surface comprising scratch-off print layers are three-fold. Firstly, while the rubber blanket cylinder 70 is typically more flexible than a gravure cylinder, they are typically less flexible than flexographic plates. Consequently, to obtain a high-quality image, offset lithography requires a print surface that is smoother than that tolerated by flexography. Prior art non-graphic overprints are used in combination with flexographically printed graphic overprints and are not configured for a high-quality offset lithographic overprint. Furthermore, it is desirable to be able to print both the secure area (over the non-graphic overprint) and the graphic area with a graphic overprint in one step using offset lithography. For example, U.S. Pat. No. 5,569,512 describes such a process employing flexography. However, typical non-graphic overprints (i.e. printed over scratch-off layers) are relatively thick whereby the print surface is excessively elevated above the substrate frustrating the application of a graphic overprint across the entire surface of the ticket by offset lithography.
Secondly, offset lithography employs inks that are highly viscous, with high tack and with a high shear characteristic as compared to the relatively thinner, liquid inks employed in gravure or flexography. Accordingly, offset lithography has a greater tendency than gravure or flexography to “pull” on the print surface during the printing process causing picking and damage to the layers of prior art non-graphic overprints. This occurs most readily where the surface is not smooth or where it presents an edge, a bump or a sharp change in elevation relative to the substrate. Accordingly, a relatively smooth print surface, having a relatively low elevation over the substrate, is required in order to minimize such steps or edge.
Thirdly, as described above, the offset lithographic process relies upon the fact that the dampening solution and the inks properly adhere to respective areas of the plate cylinder 60 and do not mix. However, this requires that the pH of the dampening solution be maintained within certain limits. Although it is not ideal, it is typical that a very small amount of the dampening solution is transferred during the printing process to the rubber blanket cylinder 70 and thence to the substrate 150. Likewise, although it is not ideal, it is typical that a very small amount of the surface components of the substrate 150 are carried away by the rubber blanket cylinder 70, then passed on to the plate cylinder 60, and thereafter further passed to the dampening solution source 110. If this back-transfer of substrate components excessively alters the pH of the dampening solution, the performance of the printing process suffers.
An instant lottery ticket 10 is manufactured by application of the variable game data 170, the non-graphic overprint 180 and the graphic overprint 190 to the substrate 150, wherein the graphic overprint 190 is applied by offset lithography. In the illustrated embodiment, the layers depicted in
With reference to
The variable game data 170 comprises the game indicia common to all instant lottery tickets. The most widely accepted method for printing the variable game data is water-based inkjet, however solvent-based inkjets, toner-based imagers or any other suitable printing technology may also be used for this purpose.
A seal layer 210 provides a barrier to seal and protect the variable game data 170. A release layer 220 provides a layer from which a scratch-off layer 230, which covers the release layer 220, may be easily removed by scratching. While the seal layer 210 and the release layer 220 typically comprise more than one layer, they may comprise a single or multiple layers that may be tinted, transparent, translucent or clear. These layers guard against physical, thermal, or chemical tampering and are well known in the lottery ticket printing art. They may be solvent based or water based, which are dried using combinations of heat energy and air turbulence, or designed so as to be cured using various forms of radiation such as electron beam or ultraviolet radiation. As such, the well known chemical formulations of the materials vary widely and may include vinyl chloride resins, polyamide resins, silicone, monomers, oligomers, waxes, benzophenone, anti-foaming agents, photo-initiators and colourants.
The scratch-off layer 230, the characteristics and composition of which are also well known in the art, is typically an elastomeric layer comprising a dark-coloured latex that provides the necessary opacity and elastic properties to cover and hide the variable data yet be sufficiently removable through the process of scratching. This layer may contain several pigments dispersed in solvent based, water based or energy curable bases, and typically contains synthetic rubbers, and metals such as aluminum, copper, bronze, carbon black, graphite, or any other materials that create the necessary opaque elastomeric characteristic of a scratch-off coating. This layer may be used to absorb solvents and resist many known forms of decoding including electrostatic, X-ray, chemical, thermal, adhesive, vapour and a wide range of physical forms of attack such as lifting, pinpricking and the like.
A preparatory surface layer 240, applied over the scratch-off layer 230, comprises layers designed to shift the dark colour of the scratch-off layer 230 to one more suitable for graphic application, typically a white or off-white surface. These layers may also add opacity and/or some of security characteristics of the previous layers, including solvent sensitivity and chemical barriers. Advantageously, the materials of the preparatory surface layer 240 are selected in such a manner as to provide a print surface 250 suitable for offset lithographic overprinting.
All of the foregoing layers of the non-graphic overprint 180 may be applied to the substrate 150 by any suitable printing technology including offset lithography, flexography and gravure or a combination thereof, and preferably by flexography.
The graphic overprint 190 comprises at least one layer, but preferably a multiplicity of layers 190A-190D of ink providing any chosen images on the secure area of the ticket, and in particular on the print surface 250 of the preparatory surface layer 240. The technology of offset lithography, including the composition of offset lithographic inks and their sources of supply, are well known in the art. A graphic overprint 190 may be applied to only the secure area 30 or, alternatively, to both the secure area 30 and the graphic area 40 in a single offset lithographic printing process.
The obstacles to offset lithography described earlier are overcome by making the non-graphic overprint 180 sufficiently smooth and thin, and sufficiently strong to resist picking from the high tack of the offset inks, so as to provide a print surface 250 which is compatible with offset lithography, and without altering the dampening solution pH to such a degree that this compatibility becomes nullified during the course of the ticket printing process. Persons skilled in the art are able to realize each of these criteria successfully based on the description herein and appropriate selection of materials determined in part by whatever is chosen for the particular implementation of the offset lithographic printing process. A general description of flexographic printing is provided hereinafter, to provide the context in which the described criteria are to be realized, in this example, when applying the above-described layers of the non-graphic overprint 180.
As will be readily understood by one skilled in the art, the configuration of the anilox roll 270 and doctor blade 300 may be appropriately chosen so as to provide a layer of any desired thickness. Furthermore, the material used for any layer may be appropriately chosen so as to provide a layer with any desired characteristics including rheology. The inks used for the various layers included in the scratch-off layer 230 and the preparatory surface layer 240 (each preferably comprising a plurality of layers) are chosen to achieve the required smoothness of the print surface 250. For example, in one embodiment, the inks for each layer are chosen to have a progressively lower viscosity and are applied in progressively thinner layers.
In addition, to allow a non-graphic overprint 180 that is as thin as possible, it is preferable to adapt other parts of the ticket 10 to accomplish one or more of the desired functions of the non-graphic overprint 180. For example, the base layer 160 may be constructed so as to be substantially opaque thereby reducing the need for a thicker non-graphic overprint 180 but still providing sufficient opacity to safeguard against security compromise techniques such as candling. Selecting and constructing the base layer 160 or any other layer below the scratch-off layer 230 to have a greater opacity may, however, result in an increased thickness in those layers. To compensate for any added thickness, a further improvement to the uniformity of the thickness of the non-graphic overprint may be obtained by calendaring (a process of levelling) the construction of the non-graphic overprint prior to the application of the scratch-off layer resulting in a further improvement to the print surface. Furthermore, this process is improved by using lower cost, low density substrates further reducing the overall cost of manufacturing and enhancing the security of the ticket, particularly against abrasion resistance.
The rheology and chemistry of the ink(s) used for the preparatory surface layer 240 is (are) selected to provide a print surface 250 that is compatible with the graphic overprint layer 190 applied there over by offset lithographic printing. More specifically, these inks are selected to satisfy the criteria that any back-transfer of elements of a type to cause alteration of the pH of the offset dampening solution, will be of a limited quantity only, so as to ensure that this compatibility does not become nullified during the course of the ticket printing process.
By way of example, the materials (inks) of the scratch-off layers may be the following:
The above-indicated materials are selected in order to provide a non-graphic overprint layer 180 that is sufficiently smooth and that provides a print surface with the correct rheology and pH characteristic for graphic overprinting by offset lithography without unduly adversely altering the pH of the dampening solution.
To print the individual layers (sub-layers) of the non-graphic overprint layer 180, using flexography, a specially configured anilox roll 270, for appropriate metering of the inks applied by it, is used. This is done to address the objective that these layers be applied so as to result in a thin and smooth print surface 250. Specifically, channelled anilox rolls 270 (available, for example from Harper Graphic Solutions), configured as follows, are used by the flexographic printing stations which print the three scratch-off layers:
As will be understood by persons skilled in the art, the use of such progressively decreasing cell size of the engraved anilox roller provides increasingly uniform coverage so that any discontinuities (i.e. gaps) resulting from the larger cells and the coarser layer(s) are subsequently filled in (i.e. smoothed out) so that the surface 250 is smooth once the final layer has been applied.
A print surface prepared as described above is suitable for graphic overprinting by offset lithography. Furthermore, it is suitable for the application of graphic overprint layers by offset lithography in combination with the application of such layers by any other suitable print technology including flexography, gravure, letterpress, inkjet or digital printing.
Prior to the application of a graphic overprint, a ticket produced according to the methods disclosed herein constitutes a “white ticket” suitable for graphic overprinting by offset lithography. These white tickets could then be supplied to purchasers who themselves apply the graphic overprint. In this way, a purchaser would need only the graphic overprinting equipment and not the equipment required for the production of the white ticket. Accordingly, any number of purchasers of white tickets could apply their own customized graphic overprints while the capital equipment costs of producing the white tickets would be advantageously centralized in a white ticket manufacturer.
With the foregoing exemplary embodiment of the invention having been disclosed, it will be apparent to those skilled in the art that various changes and modifications can be made, to appropriately suit the needs and objectives of another application and still achieve the advantages of the invention, all of which are intended to fall within the scope of the invention as defined by the claims that follow.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11334705 | Jan 2006 | US |
| Child | 12779476 | US |
