US1101240A - Stencil. - Google Patents

Description

I UNITED STATES FRANK D. BELKNAIP, OF NEW YORK, N. Y.

PATENT omen.

STENCIL No Drawing Specification of Letters Patent. Patented J l ne 2-3, 1914;. Application filed October 24, 1911. Serial No. 656,851.

Be it known that I, FRANK D. BELKNAP,

- a citizen of the "United States of America,

residing at New York city, county and State of New York, have invented certain new and useful Improvements in Stencils, of which the following is a specification.

My invention" comprises an improved stencil and the sheet from which said stencil may be made by operation of an ordinary typewriting machine, or similar agency.

The underlying novel feature of m invention is the employment of a' colloid of vegetable origin as the base of a film applied to a sheet of thin paper of loose and open texture, so as to saturate and incase the fibers of such paper with and in such material. When a sheet of paper so treated is operated on by an ordinary typewriting machine or with a stylus or other device the film of incasing material'is forced aside by the type blow or stylus point, forming a stencil, across the openings of which the fibers of the .ggtper extend with little or none of the saturating material adhering to them. Through these openings ordinary printing ink will pass, while the remaining portions of the treated paper prevent the passage of such ink at any other point. The characters impressed on the. stencil sheet are then reproduced on a sheet of paper or the like placed under it, and, when a typewriting machine is used in producing the stencil, closely resemble ordinary typev writing. Stencils'of this general type have heretofore been produced by coating paper; of this kind with animal products such as gelatin or wax, and with mineral products like paraflin, but these are subject to more or less disadvantages in use. The gelatincoating when used alone or in the form of a compound the principal base of which is gelatin, is so hard and dense that it must be dampened before forming the stencil and this takes time. The moisture also may rust-the typewriting machine. The waxed paper is sticky. The parafiined paper does not give good results with a typewriting machine. I have discovered that the use of a colloid of vegetable origin produces a coating far superior for this kind of work to those formed by animal or mineral products.

The best method of carrying out. my invention at present known to me is the followin I take Irish moss, which is a typical ce llcid of vegetable origin, sometimes called rock moss, which is an ocean product growing on submerged rocks and dissolve it in hot water. I find it takes about 14 quarts of water to properly dissolve one pound of the moss The water is prefer- 3ounces of glycerin added. Sheetsof J apanese paper called Yoshino paper are saturated and coated with this solution by drawing them across the surface of the solution, or by applying the solution to the paper with a. brush, and they are then dried by hanging up in the open air. The sheets in a solution containing two parts by weight of formaldehyde and one part of glycerin and then given a final dr ing. The coating may also be applied wit a brush instead of by dipping. -The intermediate drying between the two dippings or treatments above described may be omitted in certain cases. 'The sheets so produced will form perfect stencils when written on by an ordinary typewriting machine or stylus when of duplicate copies by placing the stencils on surfaces to be printed andrunningan so formed is so delicate that the coating material can be displaced when dry by a type blow without cutting or breaklng the fibers of the paper. It is yet strong enough and cohesive enough to prevent the ink passing through portions of the paper not struck by the type faces.- It is so responsive; to impressions that the stencils may be formed by the type striking through an ordinary ink ribbon. The advantage of this flatter process is that the stencil so formed is outlined in ink and clearly legible, in fact it looks. like ordinary'typewriting so that the operator can always tell at a glance .what stencil he is using in making the duplicates or in filing or correcting the stencils, while it is difficult to read a stencil formed by blows of the bare type face except by holding it up to the light, and when animal gelatin is used as the principal sheet before the stencil becomes at all legible. The particular function of the formaldehyde apparently is the preservation of the coating from decay so that the sheet remains usable for a long period of time. It also coagulates the, colloid and thus renders the coating more permanent and reaiatant against mechanical disintegration dry, and can be used to produce thousands ably raised to the boiling point and about may be given a second dipping or coating ordinary ink roller over them. The coating .85

base, it is absolutely necessary to wet the and the dissolving action of the oils of the inks used in duplicating machines. If other colloids are used with the Irish moss, the formaldehyde has of course, the same beneficial effect on t em. The formaldehyde can be dispensed with when the stencils are to be used up quickly.

The advantages of my invention as at present understood are due to the fact that the Irish moss, being soft, requires a less quantity of glyerin to reduce it to the proper film forming consistency, and to the fact that it also forms a film more impervious to fluids. It is advantageous to reduce the amount of glycerin, because'a large proportion of that ingredient is apt to give the film an undesirable stickiness, an as it is not fixed or set by the coagulating agent, its presence in considerable quantity detracts from the permanence of the coating. The characteristic advantage which permits a stencil in accordance with my invention to be formed without previous wetting is due to the softness of the Irish moss coating while it is still impervious to liquids, and to its spongy quality which permits it to absorb and hold a'large quantity of water. In this regard the Irish moss is vastly superior to animal gelatin when used as the principal base of a coating which on exposure to the atmosphere gives up its moisture and hardens to an extent which requires a sheet coated with it to be thoroughly saturated with water before it can be stencilized on a typewriting machine. Another great advantage in the use of Irish moss is due to the fact that its characteristic constituent, car-- rageenin, is a pectin like a mucilage, and not, a gelatin. Gelatin is a nitrogen containing body, being 17 to 18 per cent. nitrogen, and is a proteid. -.Carrageenin, on the other hand, is a saccharo-colloid and contains no nitrogen. Like gelatin, it forms a elly with water but the jelly produced from Irish moss has difi'erent characteristics from that formed from animal gelatin in that it has a permanent softness and water-holding and retaining power which is highly beneficial in a coating of this character. Irish moss is a natural film or coating-producing material and is much more effective in this way than animal gelatin heretofore used as the principal base for that purpose in making typewritten stencils. That is to say, gelatin dissolved in several times its weight of water will readily pass through a fine sieve, or through a sheet of Yoshino paper, but Irish moss, though dissolved in forty times its weight of water so as to produce a very dilute solution, will notpass through the same sieve, or through the Yoshino paper, but collects thereon in a film or coating. This is probably due to the fact that the Irish moss produces solutions of much greater body or viscosity for given degrees of concentration than does gelatin, which results from the dissolved molecules or aggregates being larger, which retards their penetration of any sieve-like structure. Consequently a given thickness of coating can be produced on a sheet of Yoshino paper with a more completely hydrated solution when Irish moss is used, than when gelatin alone is employed. Such hydrated coating can be displaced by type pressure to form a stencil without the ap lication of external moisture, and as the Irish moss has the spongelike capacity for retaining the water of hydration for a long period, the above described condition persists under ordinary atmospheric conditions and the sheet can be used for stencil making at any time.

Having, therefore, described my invention, I claim:

1. A stencil comprising a sheet of thin paper of loose texture coated with a coagulated colloidal film of vegetable origin, and great moisture retaining capacity.

2. A stencil comprising a sheet of thin paper of loose texture treated with a coagulated solution of Irish moss.

3. A stencil sheet formed of paper of loose texture coated with a film including a coagulated colloid of vegetable origin and great moisture retaining capacity andglycerm.

4. A stencil sheet formed of paper of loose texture coated with a coagula'ted film including Irish moss and glycerin.

5. A stencil sheet composed of paper of loose texture treated with a solution including a colloid of vegetable origin and great moisture. retaining capacity and formaldehyde. 1

'6. A stencil sheet composed of paper of loose texture coated with a film including Irish moss, glycerin and formaldehyde.

7. As an article of manufacture for use in forming stencils, a sheet of Yoshino paper coated with a film including a colloid of vegetable origin and great moisture retaining capacity, glycerin and formaldehyde.

8. A sheet adapted to be stencilized by type pressure comprising a sheet of thin paper of loose texture treated with a coagulated solution of a colloid of vegetable origin, and great moisture retaining capacity.

9. A sheet adapted to be stencilized by type pressure comprising a sheet of thin paper of loose texture treated with a coagulated solution of Irish moss.

FRANK D. BELKNAP.

Witnesses A. PARKER-SMITH, M. G. CRAWFORD.