JPS6311160B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention [Industrial Field of Application] The present invention relates to an improvement in a method for revealing hidden printing, and also includes a printed matter having a hidden printing portion used for carrying out the method.

[Prior Art] There have long been many attempts to prevent counterfeiting of printed materials such as securities, and some of them have been put into practice. For example, there are methods such as Sammel relief printing, mechanical engraving, hand engraving, and methods using printing ink that changes color when erased. However, the more effective these methods are in preventing counterfeiting, the higher the cost required to produce the printed matter, the larger the equipment used to determine authenticity, and the more time it takes to determine authenticity. I had a problem with it getting wet.

Therefore, we can instantly determine the authenticity of securities.
A technique has been developed that allows this process to be carried out easily. The securities are printed with characters, symbols, patterns, or a combination of these using a color developer that causes a color reaction and develops color when it comes into contact with the paper surface as a colorless printing ink. It is what it is.

However, when using this technology, the degree of light reflection differs between the film of colorless printing ink containing a color developer and the underlying paper surface, so it is difficult for the human eye to recognize hidden printing and its contents. easy to be
Moreover, the fact that the securities have been exercised cannot be clearly indicated on the certificate.

[Problem that the invention seeks to solve]

It is an object of the present invention to improve the above-mentioned points, to make it difficult for the existence and contents of hidden printing to be known, to easily determine the authenticity of securities in an instant, and to provide information on whether hidden printing has been exercised. The purpose is to provide a hidden printing technology that can clearly display the information on the face of the card.

Therefore, the present invention includes the above-described method for revealing hidden printing, as well as an object of providing a printed matter having a hidden printing portion that cannot be recognized by the human eye.

Structure of the Invention [Means for Solving the Problems] The method for revealing hidden printing of the present invention is to use a color developer that causes a color reaction when it comes into contact with a color former to develop a color, into a colorless printing ink. Use it as a cover to perform hidden printing. For a printing material on which at least a part of the printing material has been printed using colored printing ink,
It consists of applying an ink containing a coloring agent and a pigment having a hue different from that of the coloring agent, for example, by applying it by means such as coating.

The printed matter 1 having a hidden printing part of the present invention is produced by printing characters, symbols, or patterns on a paper surface using a color developer that causes a color reaction and develops color when it comes into contact with a color former as a colorless printing ink. The combination is hidden and printed, and at least a portion of the hidden printing is overlaid with letters or background patterns using colored ink, which can be revealed using a coloring agent.

In addition to the commonly used acid clay or activated clay, substances that cause a color reaction as a color developer include the commonly used acid clay or activated clay.
Examples include novolac resins and n-alkylpyridinium metal salts, and it is easy to prepare printing inks containing these.

The main coloring agent for the revealing ink is one that is used as a pressure-sensitive dye, and phthalide compounds such as the well-known crystal violet lactone are typical, but benzoylleucomethylene blue and other phthalide compounds are suitable. There are also acylleucomethylene blue, fluoran compounds, and spiropyran compounds.

The dye to be added can be arbitrarily selected from colored dyes or pigments, but it is of course required that it does not have an adverse effect on the color development of the color former. In addition, the concentration should be kept at a level that achieves the purpose of coloring the face of the card, but allows the color development by the coloring agent to be sufficiently recognized.

The coloring agent and the pigment are dissolved in a suitable solvent common to both to form an ink for revealing hidden printing. Solvents with adequate penetration and volatility are preferred, and alcohol/water mixtures and the like may generally be convenient.

The revealing ink may be used in the form of a felt tip pen, or alternatively it may be impregnated into a stamp pad and applied onto the face of the note with the "PAID" or "PAID" rubber stamp.

[Effect]

Now, if we take a gift certificate as an example and explain it with reference to drawings, Figure 1 shows the entire surface, and Figure 2 shows Figure 1A.
- As the enlarged cross section in the A direction is schematically shown,
The gift certificate 1 is printed on a paper surface 11 which is a printing material.
The color developer is colorless printing ink, and the word "Genuine" is hidden and printed on the entire ticket surface like a background pattern.1
2, and characters and background patterns 13 are printed using general colored ink. Here, colored refers to hues other than colorless and transparent. If a colorless printing ink containing a color developer is simply printed on a paper surface, the degree of light reflection between the ink film and the underlying paper surface will be different, so it will be easily recognized by the human eye.
If at least a part of it is printed with colored ink, hidden printed characters and figures will become less noticeable, and the effect of hidden printing will be ensured. Printing with colorless printing ink cannot be photographed or copied using a copier, thus preventing counterfeiting.

If the above-mentioned ink that reveals hidden printing is applied to this gift certificate, the words ``Genuine'' will appear. That is, as shown in FIG. 3 and FIG. 4, which correspond to FIG. 1 and FIG. 12A.

One feature of the present invention is that the ink that reveals hidden printing contains not only a coloring agent but also a pigment having a hue different from that of the coloring agent. This makes it possible to instantly determine the authenticity of a security by revealing hidden printing, and at the same time coloring the face of the security with the above pigment to clearly record the fact that the security has been exercised. can.

Therefore, it is possible to eliminate all the troublesome methods used in the past, such as writing with magic ink, stamping, or punching. If you want to ensure prevention of reuse, you can create a revealing ink by selecting a pigment that will not disappear when erased, or if you want to further enhance the effect, you can specify the areas where hidden printing will be done. If it is determined that the authenticity must be determined at that part, it is possible to check that once the color has developed and is erased by some means, the color will not develop again.

Effects of the Invention According to the method of revealing hidden printing of the present invention, it is possible to easily determine the authenticity of securities in an instant, and to clearly indicate on the face of the securities that the securities have been exercised.

The printed matter with the hidden printing part used to carry out the above method cannot be recognized by the human eye, so that the effect of the hidden printing is ensured.

In addition to securities, the present invention can widely respond to the desire to apply hidden printing and reveal it at a desired time.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a gift certificate, which is an example of a printed matter having a visible hidden printing portion according to the present invention, and FIG. 2 is a diagram schematically showing an enlarged cross section taken along the direction A-A in FIG. It is. FIG. 3 is a diagram showing a state in which ink for revealing hidden printing according to the present invention is also applied to the A-A portion of the gift certificate in FIG.
The figure is a diagram corresponding to FIG. 2 of the portion AA in FIG. 3. 1...Printed material (gift certificate) with hidden printing part, 1
1... Paper surface, 12... Hidden printing (unrevealed), 12A...
Hidden printing (after revealing), 13...Printing of characters and background patterns using colored ink, 2...Ink for revealing.

Claims (1)

[Scope of Claims] 1 Hidden printing is performed using a color developer that causes a color reaction when it comes into contact with the color former to develop color, as a colorless printing ink, and at least a portion of the color developer is coated with colored printing ink. A method for revealing hidden printing, which comprises applying an ink containing a coloring agent and a pigment having a hue different from that of the coloring agent to a printed material that has been repeatedly printed. 2. The method for revealing hidden printing according to claim 1, wherein the color developer is acid clay or activated clay, and the color former is crystal violet lactone. 3 Hiding characters, symbols, patterns, or combinations thereof are printed on paper using a color developer that causes a color reaction and develops color when it comes into contact with the color developer as a colorless printing ink, and this hidden printing A printed matter that has a hidden printed part that can be revealed by a coloring agent, which is made by overlapping printing of characters or background patterns using colored ink on at least a part of the printed matter. 4. Printed matter having a hidden printed part as set forth in claim 3, which is securities.