US2780991A - Cushion sheet for stencil sheet assemblies - Google Patents

Description

Feb. l2, 1957 T. u. MARRON Erm. 2,780,991

CUSHION SHEET FOR sTENcn. SHEET ASSEMBLIES Filed Feb. 2, 1951 l I f I 11V V EN TORS.'

TTBNFYS.

Uiffd Statement i CUSHION SHEET FOR STENCIL SHEET ASSEMBLIES Thomas U. Marron, Chicago, and Keith S. Hoover, Elmburst, Ill., assignors to A. B. Dick Company, Niles, Ill., a corporation of Illinois Application February 2, 1951, Serial No. 209,078

1 Claim. (Cl. lill-128.2)

rlfhis invention relates to stencil sheet assemblies and particularly to cushion sheets used with the stencilizable sheet in the manufacture of a stencil.

Stencilizable sheets of the type generally employed for stencil duplication work are manufactured of a porous base tissue that is coated or impregnated with an impressionable or displaceable composition that is usually based on a waxy, nitrocellulose or resinous material selected or modified to embody the desired ow characteristics. In the manufacture of stencils, as by typing, stylus work or other means, it is the usual practice to operate on a stencilizable sheet backed by a cushion sheet which may be formed of paper, textile fabric, or the like, preferably having a waxy coating composition on one or both faces, the coated surface adapted to be arranged adjacent the stencilizable sheet during stencilizing operations.

Very often the stencilizable sheet andthe cushion sheet are marketed with a backing sheet as a package with the members usually secured one to another along an edge portion with perforations or other means being provided along the edge of the cushion sheet for separation thereof when stencilizing operations have been completed.

lt has been found that the surface characteristics existing between the coated or uncoated cushion sheet lying in surface contact with the coated or impregnated stencilizable sheet are such as to cause adherence of the sheets one to another soV as to impart a tendency towards lamination. Separation thereof is rendered diffrcult and such intimate contact between the cushion sheet and the stencil sheet seems to cause wrinkling which has been found objectionable in stenciling operations and which detracts greatly from the appearance of the assembly.

lt is an object of this invention to produce a cushion sheet which is not subject to the objections described and it is a related object to provide a cushion sheet having little adherence to the under side of the stencil sheet when in the assembled relation.

Another object is to produce a cushion sheet which may be packaged with a stencilizable sheet without causing wrinkling or being subject to wrinkling and which will permit the use of a stencil sheet assembly characterized by improved visibility and appearance.

A further object is to produce a stencil sheet assembly in which the sheets are easily separable and formed of low cost materials.

These and other objects and advantages of this invention will hereinafter appear and for purposes of illustration, but not of limitation, embodiments are shown in the accompanying drawing in which- Figure 1 is a top plan view of a cushion sheet embodying features of this invention;

Figure 2 is a sectional view of a stencil sheet assembly which makes use of a cushion sheet of the type shown in Figure l;

Figure 3 is an enlarged sectional view taken through 2,780,991 Patented Feb. 12, 1957 v2 a portion of the cushion sheet shown in Figure 1, and

Figure 4 is a fragmentary top plan view of a modified form of cushion sheet embodying features of this invention.

It has been found that adhesion or the tendency toward lamination between the stencil or stencilizable sheet and the cushion sheet can be markedly reduced or substantially completely eliminated and Wrinkling of the type which is ordinarily occasioned upon prolonged contact between the smooth surfaces having oil, waxy, or constituents in one which plasticize materials in another, can be greatly reduced when the cushion sheet is provided with an embossed pattern substantially throughout its usable area. It is best to have the embossments in the form to provide protuberances which extend from the face of the sheet in the direction of the stencilizable sheet so as to provide for minimum contact therebetween. When the cushion sheet is in the form of a coated sheet adapted to lie adjacent the under side of the stencilizable sheet, it is preferred to arrange the cushion with the embossments on the side adjacent the stencil sheet. Substantial elimination of the tendency toward wrinkling and marked reduction in adhesion or lamination also results, but to a lesser extent, when the embossments are formed to provide protuberances which extend in a direction away from the coated surface, when employed, and away from the stencil sheet.

The pattern of embossments will take any form which will provide line protuberances closely spaced apart across the sheet. Planar spacing, dimensions, shapes and physical make-up of the protuberances bear some intluence on the contact behavior between the cushion and the stencil sheet and thereby inuence the amount of adhesion, if any, and the area of contact, Excellent results are secured when the line pattern is in the fonn of a criss-cross arrangement, such as the wallie type formed by closely spaced, crossing vertical and horizontal lines 10 and 11, respectively, in the cushion sheet 12, with the line spacings about f to 1/2 inch; apart. Effective use can be made of cushion sheets 13 having a line pattern which extends only in one direction, such as the horizontally spaced lines 14, as shown in Figure 4, or in the alternative the lines may all extend vertically, or in oblique directions, or in diamond shaped patterns, or in circular and curvilinear patterns or combinations thereof.

The described linear patterns may be formed in the cushion sheet by die-pressing or other suitable means before or after the coating is applied thereon. The pattern arrangement of spaced embossments 10, which leaves curvilinear valleys 16 therebetween, seems to eliminate wrinkling not only by reason of the fact that there is less contact between the surface of the stencilizable sheet and the cushion sheet but so subdivides the sheet that continuity across the sheet is obviated and the'inuence of one portion on another is greatly minimized. It is believed also that the pattern arrangement substantially conceals and overcomes the tendency for wrinkling and markedly reduces the tendency toward lamination.

Whatever the reason, the stencil or the stencilizable sheet and the cushion sheet are able to retain a very attractive appearance independent of their time and contact with each other and separation of the sheet one from another is greatly facilitated.

Frequently the stencilizable sheet and the cushion sheet are marketed as a package wherein the stencilizable sheet 17 is xed along one edge to a backing sheet 18 with the cushion sheet 12, embodying features of this invention, positioned therebetween with perforations or other separating means along the joined edge portion to permit easy removal when stenciling operations have been completed. When used Without preassembly into a stencil sheet assembly, the cushion sheet 12 may merely be interleaved between thestencilizable sheet and the backing sheet for stenciling operations. It will be understood that numerous 'changes may be made in the details of construction, arrangement and operation Without departing from the spirit of the invention, especially as defined in the following claim.

We claim:

In the combination with a stencil sheet, a cushion sheet underlying theV stencil sheet comprising a base sheet dimensioned to correspond with the stencil sheet, a continuous coating on the side of the base sheet adjacent the stencil sheet when in position of use, said cushion sheet having an overall pattern of embossments linearly arranged in parallel relation and spaced from 1/16 to 1/2 inch one from the other with valleys therebetween that minimize contactbetween the coated side of the cushion sheet and the stencil sheet to reduce adhesion and the 4 possibility of lamination between the two adjacent surfaces and to reduce wrinkling in said sheets.

References Cited in the file of this patent UNITED STATES PATENTS 563,355 Broderick July 7, 1896 1,188,937 Hill June 27, 1916 1,332,141 Ohashi Feb. 24, 1920 1,526,982 Hill Feb. 17, 1925 1,651,744 Van Derhoef Dec. 6, .1927 1,941,362 Newcomb Dec. 26, 1933 2,018,501 Orr Oct. 22, 1935 2,020,177 Grove Nov. 5, 1935 2,496,856 Cook Feb. 7, 1950 2,622,516 Heath Dec. 23, 1952 2,664,818 Heasley Ian. 5, 1954 ,Marron Oct. 25, 1955

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