US2150718A - Revenue stamp - Google Patents

Description

Patented Mar. 14, 1939 PATENT OFFlQE 2,150,718 REVENUE STAMP Jay .3. Lawrence, Glen Ellyn, IIL, assignor to American Decalcomania Company, a corporation of Illinois No Drawing.

Application October 8, 1936,

Serial N0. 104,715

5 Claims. (01. 4133) V This invention relates to a revenue stamp and the like.

A primary object of the invention is to provide a revenue stamp which is designed to prevent 5 counterfeiting. A further object is to provide a revenue stamp in the form of a decalcomania transfer which is equipped with a reactive material serving to readily identify the origin of the stamp when simple tests are made. Further specific objects and advantages will appear as the specification proceeds.

In my prior patent, No. 1,906,909, I provided an identifying print interposed between certain ink layers in a transfer body. One difiiculty with this form of product is that it is difficult to readily detect the print and its location in the body. The present invention is designed to employ a layer of material or material mixed with other parts of the transfer body which, while effectively concealed by the transfer body, will react to certain simple tests so as to distinguish the transfer from counterfeit stamps.

As an example, I substitute a layer of powdered metal for the identifying print illustrated in my earlier patent identified above. The powdered metal, mixed with oil or other suitable carrier, is printed directly over one of the ink layers and is then covered by succeeding ink layers. The final print is then placed on the topmost ink layer. With this construction, the intermediate layer of powdered metal is not visible to the counterfeiter and escapes his notice. However, when the transfer is removed and dropped into a solution containing a suitable re-agent for liberating hydrogen, such as, for example, HCl, there are formed hydrogen bubbles which tend to cling to the surface and soon reverse its downward direction and carry it to the top of the container. This offers a quick visual test which may be carried on by any ordinary person.

As a specific example, I print on an ink layer a metal layer consisting of powdered aluminum and oil and then conceal the metal by successive ink layers. To test the transfer, I drop it into a beaker containing a weak solution of hydrochloric acid. The aluminum combines with the chloride to form aluminum chloride. The freed hydrogen attaches in the form of bubbles to the transfer body and causes it to rise to the top.

Another Very satisfactory test is to drop the transfer into a solution of potassium hydroxide. In a well known reaction with amphoteric metal aluminum, hydrogen is liberated and. lifts the transfer slowly to the top of the beaker where it is maintained for a substantial period of time.

The above reactions are also found effective when the metal layer is formed of powdered zinc or the powder of any other metal above hydrogen in the electromotive series. In other words, in making an acid test, any metal above hydrogen is 5 found satisfactory and in making an alkali test any metal which is amphoteric and which is above hydrogen in the electromotive series is satv isfactory. v

A test which is substantially the reverse of the 10 above may also be made by employing a solvent for the white ink. Any suitable solvent, such as amyl acetate, ethyl acetate, acetone, ether, etc., may be employed. When the white ink body of the transfer goes in the solvent, the metal layer drops to the bottom. This test, however, is not as satisfactory as the above tests because it lacks the degree of visibility of the first test which makes it useful for an ordinary person unskilled in chemistry. 20

Another example of my method is as follows:

barium carbonate is formed either in a layer or otherwise dispersed in the body of the transfer. When the transfer body is removed and dropped into a solution of hydrochloric acid, carbon di- 25 oxide gas is released which forms bubbles around the transfer and tends to lift it in the liquid. Calcium carbonate is also satisfactory, operating in the same way as barium carbonate. Also any metallic carbonate is found to operate successfully.

The metal powder may, if desired, be dispersed in the layers ofwhite ink and need not be confined in a single layer. It is important that the metal powder be entirely contained within the transfer body so that it may be concealed from the counterfeiter. However, it is not so important as to its dispersion or location within the body as long as it is effectively concealed.

While in the foregoing description I have given specific examples, it will be understood that those skilled in the art can readily apply the invention to other materials without departing from the spirit of my invention. In the practice of my 45 invention it is only necessary to introduce into the body of the transfer some material which will react with some solution re-agent to free a gas, the gas forming bubbles and tending to lift the transfer body. Many examples of such re-agents 50 will readily occur to those skilled in the art.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, but the appended claims should be 55 transfer body formed by a plurality of ink impressions, and a layer of powdered amphoteric metal above hydrogen in the eleotromotive series disposed between two of said ink impressions.

4. A revenue stamp comprising a decalcomania transfer body formed by a plurality of ink impressions, and a layer of powdered aluminum disposed between two of said ink impressions.

5. A revenue stamp comprising a decalcomania transfer body formed by a plurality of ink impressions, and a layer of powdered zinc disposed between two of said ink impressions.

JAY B. LAWRENCE.