WO1991006353A1 - A method of providing protected printed information and a paper substrate using the method - Google Patents

Abstract

A method of providing protected printed information is disclosed which consists of printing the information to be protected (3, 4) on a substrate (1) using a colourless ink which can change the color of a colored ink later applied to the substrate (1) to reveal the protected information (3, 4) and a paper substrate for information, wherein plural information items (3, 4) are printed at predetermined locations on the substrate using the method.

Description

A method of providing protected printed information and a paper substrate using the method.

A method of providing prθtecteά printed information.

This invention relates to a method of providing protected printed information on a paper information-carrying substrate such as a ticket, card, or the like, printed in -accordance with this method.

The term "information" encompasses herein alphanumerical characters and various symbols to be- protected against unauthorized inspection.

Known from Belgian Patent Nc. 569587 is to provide tickets and cards or> which information to be protected is entered on a paper substrate in sympathetic ink so as to be normally invisible and only become visible following a development step whereby the ink will react chemically on exposure to a wetting medium or to heat.

Another method of providing protected printed information, primarily intended for making fiscal tickets whose back could be used as a game support, is described in Swiss Patent No. CH3572/88 by this same Applicant. This method provides for information printed in sympathetic ink to be made visible by treating the ticket back with a colourless reactant.

Both of these prior printing methods have some drawbacks. Firstly, the inks currently available commercially may undergo color changes naturally, such that the protected information, while invisible at the time of its printing, may become visible or at least perceivable absent ary treatment after a time lapse which εy not be long. This makes these methods potentially unsuitable for printing game cards where it is contemplated that the card may be nullified if more than a predetermined number of symbols or a predetermined arrangement of the same becomes visible on a wagered card.

A further drawback is that information or symbols so applied can be breached, at least in part, with relative ease.

In fact, where a specific symbol, e.g. a circle, is expected to occupy a specific position on the print substrate, such as a block thereon, by developing with a colourless reactant punctiform areas of the block, a user mεy infer whether the symbol is actually there, thus avoiding development of the whole block as prescribed by the wager organizer if the spot development gives no clue of the presence of the symbol sought. It should be noted that the illicit thus enacted vis-a-vis the game organizer would net be immediately apparent and that, although apt to be brought out by more exhaustive investigation, still represents a possible source of disputes.

Another problem connected with the use of csrds imprinted as described above is that by treating tiny blocks set close together on one card with colourless reactants, adjacent blocks may be also affected, at least in pert, which would result in nullification of the wagered card.

In addition, if the wager organizer, in order to ascertain the integrity of seemingly untreated blocks on a card, processes the whole card with a developer reactant, the information entered by the wagerer would unavoidably become confused with the checking information entered later.

Furthermore, if in sc checking a wsgered card, the absence of symbols from one or more blocks is revealed, then it would be impossible to find out with relative ease whether the missing symbols are due to errors in printing the card or a breaching attempt by the wagerer followed by an attempt to restore the blocks defaced.

The problem that underlies this invention is to provide a method of providing protected printed information whereby all the drawbacks with which the cited prior art is beset can be overcome.

This problem is solved according to the invention by a method of providing protected printed information which consists of printing said information on a substrate using a colourless ink effective to change the color of a colored ink subsequently applied to said substrate to reveal said information.

The invention features and advantages will be more clearly appreciated from the following detailed description of a preferred embodiment thereof, given by way of illustration and not of limitation with refrence to the accompanying drawings, in which:

Figure 1 is a plan view of a card printed with the method of this invention, prior to handling by a wagerer; and

Figure 2 shows the card of Figure 1 after it has been handled by the wagerer, as made apparent by the inspection check.

In the drawing figures, generally shown at 1 is a paper material substrate for protected information embodying this invention and consisting here in a card for participating in a collective wager.

The card is divided into blocks, all indicated at 2, arranged in three columns, each made up of thirteen blocks. EachiColumn has a symbol associated therewith, in this case the symbols ".;1 X 2 ", and a distribution of such symbols is settled by the wager organizer which would be winning on a specific date for the drawing. Of course, said winning distribution will vary with the drawing date. In the example shown, assuming that the card is a winning one, the distribution is as follows (from top to bottom): 1 X X 21 1 X 221 21 X.

A graphic symbol 3, a circle in this case, is shown in the blocks of the winning distribution, whereas the remaining blocks are marked with a different symbol 4, a dash in the example illustrated.

The circle and dash constitute, in the example under consideration, the information to be protected and which should only be identified by the user after completing the wager card.

The aforesaid information is printed on the card using as the printing ink an alkaline solution of sodium disulphite, e. g. a product sold by PELICAN with the trade mark SUPER PIRAT. Mention should be made, as a further example of a suitable colourless ink for this print, of stannous chloride solution.

Such solutions yield,a completely colourless ink, which is stable over time and has the property of applying a reducing action to dyestuffs normally employed for making felt pens filled with aqueous base inks, as widely available on the market (e.g. STABILO PEN (TM) 68/58). The same property is also exhibited with different colored inks, such as the ink sold by Messrs. PELICAN under reference 4001.

The aforesaid colourless inks, by reacting with an aqueous base colored ink of the type specified above, cause a change in their color, discoloring them at least in part, and this property is retained even after repeated treatment with colored ink.

In addition, that colourless ink would react in a similar manner with aqueous base colored inks having different colors, affording therefore additional advantages to become apparent in the following.

The card 1, once printed and made ready for use, has the configuration shown in Figure 1, and may be wagered on different dates, each having a specified key or distribution of the opening symbols appointed by the wager organizer. The user, on purchasing the card, will decide about the date on which it should be entered by coloring thirteen blocks, one for each line of blocks on the cardj. according to the distribution of symbols which is valid for the specific drawing date selected. The blocks are colored with an aqueous base ink of the type specified above. The blocks colored by the user carry in Figure 2 the numeral 2a. By reacting with the colourless ink used to print on the card 1 both the winning symbols (circles 3) and the losing ones (dashes 4), the color of the colored ink will undergo a change at the location of the printed symbols in an invisible way in each block, to bring out the hidden symbols in a paler color.

Where the winning symbols for the distribution valid on the selected wager date are brought out, the card will be regarded as a winning one. Of course, other wager rules may be contemplated, which are not a subject-matter of this invention.

The body in charge of checking the cards can then ascertain the integrity of the winning card by coloring the remaining blocks in a different color from that used by the wagerer. The blocks colored on inspection are denoted by the reference numeral 2b in Figure 2. In the same way, the rest of the symbols printed on the card are revealed, to bring out any attempts at coloring and subsequent masking the seemingly intact blocks. Actually, traces of discoloring solutions (substantially the equivalent of the colourless inks employed for printing the original symbols) used by the w&gerer to improperly disguise previous breaching attempts or. blocks other than those actually wagered would be brought out by a change in the color of the colored ink used by the inspector in a similar way to the color change brought abcut at the symbols originally printed o the card. As an example, Figure 2 shows breaching and later disguising attempts or. the blocks of the first line corresponding with the columns "X" and "2", and a similar disguise attempt is shown on the first block (ccrresponding with column "1"), second line.

The disguise attempts are made evident by that the symbol originally printed in invisible ink (dash 4), shows fringes not contemplated in the original print, a sign that a portion of the block has been previously cclored to ascertain the likelihood of a win according to a different distribution of symbols and that, due to the absence of winning symbols from that specific card in connection with that distribution, the card has been wagered again for a different distribution or wager date.

This later ascertainment coloring of the card, if carried out using a different color from that employed originally by the wagerer, would not alter the original wager, thus eliminating possible later disputes with the wager organizer, but directly bring out any fraudolent attempt. Such an advantage could not be achieved as easily using conventional sympathetic inks, which are usually revealed in the same color at all times.

A further advantage of the invention is that attempts at breaching on the blocks can be brought out more easily than with prior approaches because, to inspect the contents of a block, the user is to process a broader area thereof, in order to make the outline of the protected symbol visible. Also facilitated is the development of blocks which may be small in size and set close together, because the user has an immediate perception of the surface treated with the colored ink.

This same method well suits applications other than the printing of paper substrates for collective wagers; as an example, it lends itself for ensuring discretion on confidential messages, where the addressee wishes to ascertain that the contents of the message addressed to him/her has not been previously inspected by unauthorized third parties.

Claims

1. A method of providing protected printed information consisting of printing said information (3,4) on a substrate (1) using a colourless ink which can change the color of a colored ink later applied to said substrate (1) to reveal said information (3,4).

2. A method according to Claim 1, characterized in that said color change takes place by discoloration at least in part of the colored ink.

3. A method according to Claim 1 or 2, characterized in that said colourless ink is adapted to react with colored inks having different colors tc produce said color change.

4. A method according to Claim 1, characterized in that said cclourless ink comprises an alkaline solution of sodium bisulphite.

5. A e-thcd according to Claim 1, characterized in that said colourless ink comprises a solution of stannous chloride.

6. A method according to Claim 1, characterized in that said colored ink comprise,s an aqueous base ink whereon said colourless ink has a reducing action.

7. A paper substrate for information, wherein plural information items (3,4) are printed at predetermined locations on the substrate (1) using the method claimed in any of Claims 1 to 6.