US774535A - Safety commercial paper. - Google Patents

Description

UNITED STATES Patented November 8, 1904.

JAMES ROIVAN, OF OTTAWA, CANADA.

SAFETY COMMERCIAL PAPER.

SPECIFICATION forming part of Letters Patent No. 774,535, dated November 8, 1904.

I Application filed December 29. 1903. Serial 186,938. (No model.)

To all whom it may concern.-

Be it known that I, J AMES ROWAN, a subject of the King of Great Britain, and a resident of Ottawa, in the Province of Ontario and Dominion of Canada, have invented a new and Improved Safety Commercial Paper, of which the following is a full, clear, and exact description.

My invention relates to commercial paper, such as is used by bankers, merchants, and other business men, my object being more particularly to so prepare a paper that alterations in the condition of the papersuch, for instance, as the erasure of intelligible characters or the addition of said characters thereuponmay be readily detected.

A further object of my invention is to produce a paper and ink therefor such as will not deteriorate with age and in which the fabric of the paper is not injuriously aifected by ink used thereupon.

In carrying out my invention I take any commercial paper, either in the web, ream, or sheet, and pass it through a bath composed of the following substances: three ounces of prussiate of potash, one ounce of ammonia, and ten pounds of water. The prussiate of potash may be either of the yellow or red variety; but I prefer the yellow variety. When the paper is passed through the bath, as above described, the ammonia in the solution neutralizes any acids contained in the paper and prevents discoloration of the paper, while, on the other hand, the prussiate of potash renders the paper sensitive to the subsequent action of an acid. The paper is then dried and is next treated or tinted to an overprint, the ink of which is composed as follows: four parts of perchlorate of iron, four parts of potassium iodid, and one part of caustic soda or potash. This ink is of a peculiar kind. While containing both acid and alkaline substances and while these substances are admixed as stated, they do not combine with each other, because of the action of the mulling in oil or varnish. The oil or varnish, in

other words, keeps the substances apart by separately enveloping their very small particles, yet when an acid or an alkali is applied to a paper upon which the ink is printed or otherwise applied the acid or the alkali, as the case may be, unites with the perchlorate of iron or with the potassium iodid, forming a discoloration. The prussiate of potash in the paper is also affected by acids, the discoloration being thereby increased. These chemicals are mulled in linseed-oil or other suitable varnish. A little magnesia may be added,'if desired. The resulting admixture is an ink and may be applied to the paper prepared as it isdescribed in any manner, but preferably from relief-type made of wood, stone, or metal. The magnesia is not an essential element and is merely used to temper the inkthat is, it facilitates its flow upon the finished paper.

The ammonia used in the bath is for the purpose of neutralizing any acid inherent in the paper which would otherwise tend to neutralize the prussiate of potash. When paper has been subjected to a bath in which the latter chemical is dissolved, the iron oxid or pyrogallic acid of the writing fluid used in writing a document permeates the paper better and is harder to remove, and hence paper subjected to the bath as described is more effective than paper treated to an overprint even when composed of all the chemicals compounded as an ink.

In order to make the ink applicable to various tints of paper, suitable proportions of fuchsin or manganese may be added. For instance, when blue paper is treated to the bath above described and then overprinted in the manner stated its blue color becomes deeper when any attempt is made to tamper with it by the aid of an acid. This deeper blue, however, does not contrast sufficiently with the original color to render detection inevitable. After a small percentage of fuchsin has been added during the process of mulling the subsequent application of an acid to the finished paper causes a purple discoloration which renders detection certain. In like manner a small percentage of manganese may be used instead of the fuchsin when the preparation is to be used with paper having white or very light tints.

The mulling or grinding together of the chemicals mentioned, preferably with a suitable substance for tempering the ink, this substance being preferably in the form of a varnish, serves a twofold purpose, to wit: First, it reduces the admixture or composition to a certain. uniform consistancy, which is about the same as that of printing-ink, and, second, it envelops the separate particles of the active chemicals in a covering of the tempering material or varnish. This eveloping of the particles of the active materials in the varnish is very important, for the reason that it acts as a preservative for the chemicals by avoiding exposure thereof to the air and preventing volatilization of the substances used. It also prevents direct contact between the small particles of the chemicals used and the fiber of the paper, thus overcoming defects which have existed in all papers of the kind heretofore produced so far as I am aware.

In printing different designs may be employed, such as may be desired by the differentfirms for which the paper is manufactured. The design becomes conspicuous upon any attempt to tamper with the paper.

I do not limit myself to the proportions of the chemicals named nor to the order in which the chemicals are added. Various changes may be made in these two respects without departing from the spirit of my in vention. For instance, potassium iodid may be used in the bath and the prussiate of potash may be mulled in the varnish with the iron perchlorate, or the iron perchlorate may be used in the bath, the only difference being that when prepared in the several manners stated there may be a slight difference in the shade of the papers produced. Neither do I limit myself to the use of the particular sul stances stated, for the reason that chemical equivalents of any one or more of such substances may be used, if desired. The paper may be prepared by treating the paper-pulp before its conversion into paper, the pulp being subjected directly to the bath, or one or more of the ingredients may be incorporated in the pulp, the other ingredients being applied to the finished paper.

I find that ordinarily unprepared paper to which has been applied an overprint composed of the chemicals above described will give fairly good results; but my preferred method is that first described above.

Having thus described my invention, I claim as new and. desire to secure by Letters Patent 1. The process herein described of preparing a commercial safety-paper, which consists in subjecting ordinary paper to a bath consist ing of potassium prussiate, ammonia and water, and afterward treating said paper to an overprint of ink consisting of iron perchlorate, potassium iodid and a caustic alkali.

' 2. A safety commercial paper, comprising a paper substance sensitive to acids and having an overprint of iron. perchlorate, potassium iodid and an alkali.

3. A safety-paper consisting of ordinary paper overprinted with an ink composed of four parts of salt of iron, four parts of potassium iodid, four parts of prussiate of potash, and one part of caustic soda or potash, by weight.

4i. A safetypaper overprinted with substances for rendering it sensitive to acids and with other substances for rendering it sensitive to alkalies.

5. A safety-paper treated with potassium prussiate and ammonia and overprinted with potassium iodid.

6. A safety-paper treated with potassium prussiate, ammonia, potassium iodid, and a small proportion of manganese.

7. A safety-paper treated with potassium prussiate, ammonia, potassium iodid, and a small proportion of anilin coloring-matter.

8. A safety commercial paper consisting of a paper substance overprinted with an ink consisting of chemical substances having an afiinity for each other, said chemical substances being admixed in a normally inert medium separately enveloping individual particles thereof so as to temporarily prevent said chemicals from afiecting each other.

9. A commercial safetypaper consisting of ordinary paper treated with potassium prussiate, ammonia and water and provided with an overprint of ink consisting of iron perchlorate, potassium iodid and acaustic alkali.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

J AMES ROWAN.

WVitnesses:

J. ODoNAHoE, JNo. KILZALLIN.