Abstract:
Cards and methods of securing hidden symbols on cards are disclosed. The cards, such as instant-win lottery tickets, utilize continuous overprint inks that mask the boundaries between their &#34;secure&#34; and &#34;unsecure&#34; portions to inhibit unscrupulous players from successfully tampering with them. By reformulating the overprint inks to permit a single set to be applied to both portions of a card, more vibrant and aesthetically-pleasing graphics may be displayed as well while utilizing fewer printing stations during the printing process. 
     Alternatively or additionally, the cards may be embossed for added security. Raising portions of the secure area of a card above the remainder of its surface produces irregular features, thereby inhibiting both improper removal of the upper latex or other coating and photo reproduction of the card. The varying card height caused by embossing further inhibits heat-based tampering, as heat transfer to the irregular surface is no longer uniform.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 08/407,185, filed Mar. 21, 1995, entitled &#34;Card With Integrated Overprinting,&#34; which is a continuation-in-part of U.S. patent application Ser. No. 08/195,759, filed Feb. 14, 1994, entitled &#34;Card,&#34; now abandoned, and of U.S. patent application Ser. No. 08/260,699, filed Jun. 16, 1994, entitled &#34;Simulated Foil Card,&#34; U.S. Pat. No. 5,532,046, all of which applications are incorporated herein in their entireties by this reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a card (such as a lottery ticket or game piece) in which inks are applied continuously over both its &#34;secure&#34; and &#34;unsecure&#34; portions or which is embossed for added security (or both). 
     BACKGROUND OF THE INVENTION 
     Many existing instant-win lottery cards or tickets comprise a paper substrate to which foil is laminated. The foil is then coated both to minimize oxidation and to provide an ink-retaining surface onto which symbols may be printed in a selected area. At least one additional sealant may be applied to the inked surface to protect the printed symbols, and a single opaque metallic latex covering used to obscure them from view. Post purchase or distribution, the ticket bearer, or player, typically removes (&#34;scratches off&#34;) the latex covering to reveal the hidden symbols. Existing tickets often further include at least one &#34;release&#34; coat interposed between the latex covering and protective coating to facilitate the removal of the latex covering in use. 
     The area of the ticket in which the symbols are printed and the latex covering is applied is often called the &#34;secure&#34; region of the ticket. Because it contains the symbols that ultimately determine whether a player has won a prize, this region is typically protected from certain types of tampering, both pre- and post-purchase. U.S. patent application Ser. No. 08/195,759, for example, discusses various methods of improving the security of the hidden symbols on the card against physical, electrical, magnetic, chemical, and artistic tampering. Using an opaque latex covering itself helps protect the secure region of the ticket from certain optical tampering such as candling. To ensure appropriate adherence to the latex covering, specially-formulated &#34;overprint&#34; inks, typically requiring separate print stations, are used. 
     By contrast, the remainder of the ticket is known as the &#34;unsecure&#34; portion or area. It often includes aesthetic graphics or vibrant pictures, printed with inks different than those used in the secure region, designed to enhance the overall appeal of the ticket to potential purchasers. The unsecure region need not include an opaque latex covering, as candling or otherwise tampering with it will not reveal the nature or the content of the hidden symbols. Moreover, because the latex covering increases the manufacturing cost of the ticket, applying this covering to the unsecure region is not economical, 
     Notwithstanding the security devices employed in connection with these tickets, some possibility remains that unscrupulous players may attempt to alter the characteristics of the tickets. Results sought to be achieved in these instances include changing a &#34;losing&#34; ticket to a &#34;winning&#34; one, increasing the value of the prize awarded on a &#34;winning&#34; ticket, or determining, in advance of purchase, whether a ticket is a &#34;winning&#34; one and the nature of the award. Persons to whom tickets are accessible, for example, may attempt to locate the boundaries of the latex coverings and remove those coverings intact so they may observe the (then visible) symbols and, if necessary, reattach the coverings without raising suspicions that tampering has occurred. The structures of existing tickets do not necessarily fully deter these attempts, as the differing inks used in the secure and unsecure regions often demarcate (rather then camouflage) the boundaries of the latex covering. 
     SUMMARY OF THE INVENTION 
     The present invention addresses this and other issues respecting existing tickets by applying inks continuously over both their secure and unsecure portions. Unlike current techniques, which use different ink formulations for corresponding portions of the tickets, the present invention utilizes a single formulation adapted to print suitably in both areas. Providing graphical continuity over both regions of a ticket inhibits the improper removal of the latex covering, as the boundaries of the covering are &#34;masked&#34; and thus substantially more difficult to locate. Doing so also improves registration of the components of the overall design, usually resulting in enhanced aesthetic appeal, and eliminates the need for some of the differing inks and print stations now required to produce existing tickets. 
     Inks of four colors (yellow, magenta, cyan, and black) are often used as part of the present invention. Typical formulations of the inks include, by weight: 
     
         ______________________________________ethyl acetate     19-58%colored nitrocellulose              1-25%chipsacrylic resin     15-25%propyl acetate     20-60%,______________________________________ 
    
     with a preferred embodiment having, by weight, 30% ethyl acetate, 11% colored nitrocellulose chips, 19% acrylic resin, and 40% propyl acetate. Reformulating the inks in this manner produces acceptable results--including vibrant graphics--over paper, foil, and latex, permitting continuous printing in both the secure and unsecure areas of a ticket. These formulations also reduce &#34;blocking,&#34; an industry term describing the transfer of ink from the front of one ticket to the back of another ticket when the tickets are wound in a roll. Polyamide resins (in quantities typically ranging between 1-35% by weight) and spirit-soluble nitrocellulose (in quantities typically ranging between 5-30% by weight and having viscosity of approximately 18-25 cps) may also be added (or substituted for the acrylic resin) if desired, and among the colored nitrocellulose chips suitable for use are 
     Diarylide MX Yellow (color index 13); 
     Diarylide Yellow (color index 14); 
     Lithol Rubine Red (color index 54:1); 
     Phthalocyanine Blue (color index 15:3); 
     Carbon Black (color index 7); 
     Red, Scarlet (color index 22); and 
     Phthalocyanine Green (color index 7). 
     Alternatively or additionally, tickets of the present invention may be embossed. Embossing the secure area of a ticket further inhibits improper removal of the latex covering by raising portions of the area above the remainder of the surface of the ticket. The resulting irregular features of the surface are prone to gouging or nicking when an attempt to remove the latex covering is made (as by use of a razor blade, for example), producing visible evidence of this type of tampering. Copying (particularly color photocopying) also is deterred, as the shadows and other irregularities created by the embossed features are not easily reproducible. The varying ticket height caused by embossing further inhibits heat-based tampering, as heat transfer to the irregular ticket surface is no longer uniform. 
     It is therefore an object of the present invention to provide a card in which inks are applied continuously over both its secure and unsecure portions. 
     It is another object of the present invention to provide ink formulations suitable for applying over both the paper or foil used in the unsecure area of a ticket and the latex or other synthetic rubber applied in the secure portion of a ticket. 
     It is also an object of the present invention to provide techniques that eliminate the need for multiple sets of print stations corresponding to multiple formulations of inks. 
     It is a further object of the present invention to provide a card that masks the boundaries between its secure and unsecure portions. 
     It is yet another object of the present invention to provide inks including (but not limited to), by weight, 19-58% ethyl acetate, 1-25% colored nitrocellulose chips, and 20-60% propyl acetate, for use in connection with a card such as a lottery ticket or game piece. 
     It is an additional object of the present invention to provide inks consisting essentially of, by weight, 30% ethyl acetate, 11% colored nitrocellulose chips, 19% acrylic resin, and 40% propyl acetate. 
     It is furthermore an object of the present invention to provide a card that is embossed for enhanced security. 
     It is also an object of the present invention to provide a card whose secure area has an irregular surface. 
     It is an additional object of the present invention to provide a card having a varying height, thereby inhibiting, among other things, mechanical removal of an upper layer of the card. 
     Other objects, features, and advantages of the present invention will become apparent with reference to the remainder of the text and the drawings of this application. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of a card of the present invention having a paper base. 
     FIG. 2 is an exploded perspective view of an alternative card having a foil, rather than paper, base. 
     FIG. 3 is an exploded perspective view of an embossed card of the present invention having a paper base. 
     FIG. 4 is an exploded perspective view of an alternative embossed card having a foil base. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 illustrates an embodiment of card 10 of the present invention. If desired, card 10 may be divided into &#34;secure&#34; and &#34;unsecure&#34; areas 14 and 18, respectively, with symbols 22 printed in secure area 14. Such symbols 22, initially covered by opaque material (and therefore hidden from view), provide the information sought by the player or purchaser of card 10. 
     As shown in FIG. 1, card 10 comprises a paper base 26, which may (but need not) be conventional eight or ten point board stock. Unlike the card 10A of FIG. 2, foil is not laminated to base 26 or otherwise used as base 26A. As a result, card 10 is easily recyclable, and base 26 itself may be formed from recycled fibers. Card 10 nevertheless provides many of the advantages of foil-based card 10A, including resistance to known optical, magnetic, chemical, physical, artistic, and electrical compromise techniques and, when subjected to certain chemical tampering, evidence that such tampering has occurred. Alternatively, a synthetic substrate may be used as base 26 or 26A instead of either paper or foil. 
     FIGS. 1-2 show various ink layers and coatings that may be applied to bases 26 and 26A to enhance the security of cards 10 and 10A. As detailed FIG. 1, foundation coating 30 covers the portion of base 26 in secure area 14. Foundation coating 30 increases the opacity of card 10, reducing the possibility of successful optical compromise through candling. Cards 10 and 10A may also include contrast coating 34 if desired, typically a white or light-colored material onto which darker symbols are printed. Both foundation coating 30 and contrast coating 34 (when present) are adapted to receive the ink used to print symbols 22 and, for card 10, provide a durable surface to substitute for that furnished by the foil of card 10A. 
     Foundation coating 30 comprises a dark-colored, solvent-soluble ink (e.g. blue) with a high metal content (typically aluminum, bronze, or copper) and a vinyl chloride base resin. Foundation coating 30 additionally may, but need not, include carbon black to inhibit electrostatic tampering from the underside 36 of card 10. Like the foil of card 10A, the colored ink and other contents of foundation coating 30 further prevent unscrupulous players from viewing symbols 22 by removing the fibers from base 26. The fugitive dye of foundation coating 30 (if present) also is designed to bleed through underside 36 of card 10 when immersed in chemicals, evidencing an attempt to wick the ink of symbols 22 to underside 36 for viewing by an unscrupulous player. A suitable contrast coating 34 for card 10 is a vinyl chloride resin (dissolved in acetate solvent) with titanium dioxide pigment. 
     Seal coating 38 covers symbols 22 and functions as a barrier to seal symbols 22 from other coatings applied to cards 10 and 10A and guard against chemical tampering by unscrupulous players. Cards 10 and 10A may additionally include a second sealant (not shown) for similar purposes and to reduce reliance on automatic equipment fully covering symbols 22 with seal coating 38. In these embodiments, either or both of seal coating 38 and the second sealant may be a water-white solution of vinyl chloride resin. Although transparent, either seal coating 38 or the second sealant may be tinted if desired to inhibit or deter photocopying of symbols 22. 
     At least one release coating 46, applied over seal coating 38, permits first and second latex coverings 54 and 58, when present, to be removed by the player to reveal symbols 22. Release coating 46 typically contains alcohol-soluble polyamide resin and zinc stearate, and may contain silicone as well. This structure permits card 10 to withstand greater temperatures without degradation than other typical non-foil pieces, reducing the possibility of successful heat-based tampering by unscrupulous players. Utilizing more than one release coating 46 allows each to be thinner than a single coat, furthermore, thereby drying more quickly and allowing more rapid processing through automatic equipment. Multiple release coatings 46 also promote complete coverage of secure area 14 and facilitate more rapid and easier removal of respective first and second (latex) coverings 54 and 58 by the player. 
     Alternatively, release coating 46 may be a varnish cured by ultraviolet radiation to enhance the gloss of card 10 and further seal the layers of the card 10 from contaminants or abrasion. Because this coating 46 is not air-dried, it remains unfixed until exposed to ultraviolet radiation. Non-uniformities in the thickness of applied coating 46, therefore, remain amenable longer to correction, providing a smoother, glossier result than many air-dried coatings. Exemplary compositions for such release coating 46 include (by weight) approximately 55-65% monomer, 15-25% epoxy oligomer, 8-10% benzophenon and, if appropriate, various anti-foamants, flow/levelling agents, photo-initiators, and synergists. Because these components cross-link when exposed to ultraviolet radiation, this alternative release coating 46 typically cures to a hard and durable finish. The alternative release coating 46 may additionally substitute for either or both of seal coating 38 or the second sealant (and may therefore also include a colorant). 
     Applied atop release coating 46 is first covering 54. First covering 54 is an opaque, typically (although not necessarily) black latex comprised of solvent-soluble synthetic rubber with predispersed pigment and is available from KVK USA, 19A Home News Road, New Brunswick, N.J. 08901. Second covering 58, applied atop first covering 54 of FIG. 1, is also an opaque, solvent-soluble synthetic rubber containing predominantly metal particles (such as aluminum, copper, or bronze) and black pigment. First and second coverings 54 and 58 combine to inhibit candling of card 10, with the metallic composition and black pigment present additionally deterring certain chemical tampering of both cards 10 and 10A. Because the synthetic rubber of first and second coverings 54 and 58 is an electrical insulator and does not react with acids or bases, cards 10 and 10A are less likely to be electrically or chemically compromised by an unscrupulous player as well. In some embodiments of cards 10 and 10A, first covering 54 may also include metal particles to enhance opacity, or be otherwise appropriately formulated to provide a removable means for obscuring symbols 22 from view. 
     Overprinting 62, finally, may also be applied to cards 10 and 10A. Overprinting 62 comprises one or more inks 64, each adapted to adhere suitably to each of (paper) base 26, (foil) base 26A, and the latex or other material used as either first covering 54 or second covering 58. Consistent with FIGS. 1-2, use of no more than four inks 64A-D (and only three if black ink 64D is excluded) permits creation of vibrant graphics in virtually all colors for both secure area 14 and unsecure area 18 of cards 10 and 10A. By contrast, existing cards require twice the number of inks--and thus twice the number of print stations--to accomplish this purpose, one set each for secure area 14 and unsecure area 18. Of course, if desired more than four inks 64 may be used in connection with the present invention. 
     
         ______________________________________ethyl acetate     19-58%colored nitrocellulose              1-25%chipsacrylic resin     15-25%propyl acetate     20-60%,______________________________________ 
    
     with the colored nitrocellulose chips determining the color of each ink 64 (e.g., yellow for ink 64A, magenta for ink 64B, cyan for ink 64C, black for ink 64D). These chips are commercially available from numerous manufacturers, including BASF, KVK USA, and PennColor. In a preferred embodiment, each ink 64 has, by weight, 30% ethyl acetate, 11% colored nitrocellulose chips, 19% acrylic resin, and 40% propyl acetate. Polyamide resins (in quantities typically ranging between 1-35% by weight) and spirit-soluble nitrocellulose (in quantities typically ranging between 5-30% by weight and having viscosity of approximately 18-25 cps) may also be added (or substituted for the acrylic resin) if desired. 
     By functioning in both secure area 14 and unsecure area 18, inks 64 permit continuous printing, and thus graphical continuity or integration, in both areas. Doing so also masks the boundaries of first and second coverings 54 and 58, inhibiting their improper removal by making the boundaries substantially more difficult to locate visually. Using inks 64 to provide integrated overprinting 62 further improves registration of the components of the overall design, usually resulting in enhanced aesthetic appeal. As formulated, inks 64 additionally reduce blocking when cards 10 or 10A are wound in a roll. 
     Using inks 64 provides other advantages for gravure, flexo, letter press, and possibly silk screen printing processes as well. By eliminating the need for additional printing stations, for example, inks 64 reduce both the cost of and &#34;make ready&#34; time for a printing effort. The unused printing stations, moreover, are available for other jobs or efforts running concurrently. 
     FIGS. 3-4 illustrate cards 100 and 100A including embossing 104. As shown in FIGS. 3-4, embossing 104 may be present in both secure area 14 and unsecure area 18. Doing so generally enhances the aesthetics of cards 100 and 100A, providing them with a textured appearance. Embossing 104 present in secure area 14 also increases the security of cards 100 and 100A, however, providing an irregular upper surface 106 that inhibits intact removal of first and second coatings 54 and 58. Attempting to remove first and second coatings 54 and 58 using a razor blade, for example, is likely to result in gouging or nicking the coatings themselves. The shadows and varying height of secure area 14 caused by embossing 104 additionally deter conventional two-dimensional photocopying of cards 100 and 100A and heat-based tampering, as heat transfer to upper surface 106 is no longer uniform. 
     Typically added after the remainder of cards 100 and 100A are manufactured, embossing 104 may be accomplished by feeding cards 100 and 100A through a pair of embossing rollers. Such rollers may include a roller having a raised (&#34;male&#34;) surface paired either with a flat (&#34;neutral&#34;) roller or a recessed (&#34;female&#34;) roller. Those skilled in the art will recognize that other mechanisms for creating embossing 104 may be employed, however. 
     The foregoing is thus provided for purposes of illustrating, explaining, and describing embodiments of the present invention. Further modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of the invention. In particular, white ink 64 may also be formulated and applied atop first covering 54 or second covering 58 if desired. Moreover, either of first covering 54 or second covering 58 may be omitted if desired (as shown in FIG. 4). FIGS. 3-4 additionally illustrate use of Benday patterns 108 between seal coating 38 and release coating 46. Patterns 108 provide further security for cards 100 and 100A, as they typically become visibly discontinuous when subjected to certain types of tampering.