Improvements in Stencil Sheets.
Year: 1896

page_text: Date of Application, 4th Aug., 1896-Accepted, 12th Sept., 1896
COMPLETE SPECIFICATION.
Improvements in Stencil Sheets.
I, THOMAS HEADLY STACKHOUSE, of 1627 Dauphin Street, in the City and
County of Philadelphia, State of Pennsylvania, one of the United States of
America, Manufacturer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:-
My invention relates to improvements in stencil sheets, and more particularly to
improvements in that class of stencil sheets which are adapted to be cut upon a
typewriting machine; and the object of my invention is to furnish a compound
stencil sheet, the tensile strength of which will be much greater than that of any
stencil sheets heretofore made, ànd from which a much greater number of
impressions or copies can be made than has heretofore been possible.
The base of my stencil sheet is formed of a sheet of fibrous paper of a thin, open
texture, preferably of the paper known as Japanese dental or Yoshino paper, which
is treated with wax in the usual and well known manner for producing stencil
sheets. Upon one or both sides of the base sheet, I place a sheet of thin, close-
grained paper, preferably a highly calendered tissue paper containing sizing, which
is also preferably waxed or oiled so as to make it impervious to .ink.
The latter sheet or sheets of paper may be secured to the base sheet by pressure
between rolls which may be either cold or hot, or by means of a hot iron passed
over the sheets after they have been placed on top of one another; if heated
rolls or irons be used, the close-grained paper need not be waxed, as these irons or
rolls would cause the wax on the base sheet to melt, which would then be absorbed
in sufficient quantity by the unwaxed sheet or sheets to make them impervious
to ink or moisture.
The stencil is formed or. cut upon the sheet in the usual and well known manner
by a typewriting machine or other instrument; the close-grained paper upon being
struck by the type or other instrument is at that point wholly or partially destroyed
or cut through, while the fibres of the base sheet, being exceedingly tough and
strong, suffer little or no injury, but the wax which they hold is, where the
type strike, shattered and pushed aside or otherwise removed, permitting the free
passage of ink at these points.
The use of the thin, close-grained paper in connection with the base sheet of
open fibrous texture permits the use of a much harder wax, that is, one of a higher
melting point, than is possible where the base sheet alone is used, the advantages
of which in warn weather will be obvious.
In the accompanying drawings, Fig. 1 shows my improved stencil sheet, formed
of a base sheet, one side of which carries a sheet of the close-grained calendered
paper, and Fig. 2 a stencil sheet formed of a base sheet placed between two sheets
of close-grained calendered paper, A being the base sheet and B the covering
sheets.
In cutting the stencil the covering sheet B preferably receives the blow of the
type, if the porous sheet is coated upon but one side with paper.
The wax used for coating the porous paper may be that generally employed for
this purpose, which is composed largely of paraffine, although any suitable
material impervious to ink may be used.
The commercial typewriter stencil paper now in general use is made by coating
Japanese dental or Yoshino paper with a soft wax, largely paraffine. Such. stencil
paper is very frail and delicate, and is so much influenced by heat as to be of little
value in warm or even in temperate climates, where the temperature ranges

page_text: beyond 90 degrees Fahrenheit; in fact, to such an extent is such stencil paper
influenced by heat that in many cases only a few good copies can be obtained from
a stencil in warm weather.
In my stencil sheet, not only can less wax be used, but the melting point of the
wax may be much higher than is possible with the stencil sheets now in use.
I do not confine myself to the use of Japanese dental or Yoshino paper,
as any porous paper may be used as a base for my compound stencil sheet.
I have found in practice that for a stencil sheet for use in the ordinary
commercial typewriter, hetter results are obtained by coating the base sheet on but
one side with paper. Although if a very large number of copies are required, the
base sheet should have both sides coated with paper. In the latter case it generally
requires somewhat more pressure to perforate the stencil sheet.
have also found in practice that better results are obtained by coating the porous
sheet with wax in a similar mauner to that used in making the ordinary commercial
stencil sheets, and then affixing the paper coating to the said porous sheet with roll
pressure with just sufficient heat to cause the tissue paper coating to adhere firmly
to the said porous waxed sheet.
As a paper coating for the waxed porous sheet, I prefer to use a thin, close-texture,
well calendered tissue paper, containing considerable sizing. I do not confine
myself to a highly calendered tissue paper, for a paper of slightly open texture may
be used to good advantage, although I much prefer an exceedingly close-texture
highly calendered tissue. I have used-very thin Japanese tissue, giving good results,
but there are several grades of tissue papers which can be had in the market which
give satisfactory results.
I prefer to use an oiled tissue paper or a paper saturated with oil or coated lightly
with wax, unless sufficient heat is used when forcing the sheets together to cause
the wax conting of the porous sheet to impregnate the tissue sheet.
The paper coating of the porous waxed sheet should be sufficiently delicate or
brittle to be readily broken or destroyed by the blow of the types. Of course in
some cases the tissue would not be wholly destroyed although sufficiently so to show.
an almost completely broken line.
While I prefer to make my compound stencil sheet in the manner above described,
if desired both the porous sheet and the tissue sheet could be waxed or coated with
a material impervious to ink at the same operation. The art of waxing paper is
well known, and need not be described.
The art of producing stencils is also well known, and does not need description.
A stencil sheet prepared in the manner indicated may be used for the so-called
autographic process, and the same can be perforated not only with the wheel-pen,
but also with a stylus upon a roughened plate.
A stencil sheet prepared by my process possesses great tensile strength, is very
durable, and will reproduce the maximum number of copies from one stencil.
Having now particularly described and ascertained the nature of my said inven
tion and in what manner the same is to be performed, I declare that what I
claim is :
1. A compound stencil sheet, consisting of a sheet of thin, open, fibrous paper,
and a sheet or sheets of a close-grained, thin paper, said sheets being coated with a
substance or substances impervious to ink, and being secured together, substantially
as set forth.
2. A compound stencil sheet, consisting of a sheet of thin, open fibrous paper,
and a sheet or sheets of a close-grained, thin paper applied to one or both sides of
said first sheet, the whole coated with a substance impervious to ink, and being
secured together substantially as set forth.
3. A compound stencil sheet, consisting of a sheet of thin, open, fibrous paper
such as Japanese Yoshino paper, filled or coated with a substance impervious to ink
as paraffine, and a sheet or sheets of close-grained, thin paper placed upon one of
both sides of said first sheet, and secured thereto by heat and pressure.

page_text: 4. A compound stencil sheet, consisting of a sheet of thin, open fibrous paper, as
Japanese Yoshino paper, filled or coated with a substance impervious to ink, as.
paraffine, and a sheet or sheets of a close-grained, thin paper coated or filled with.
a substance impervious to ink, as paraffine or oil, placed upon one or both sides of
said first sheet, and secured thereto by pressure.
5. A prepared compound sheet for use as a stencil sheet, consisting of two or more.
sheets, one of which is of an open, porous material, the other of close texture, one
or more of said sheets being coated with a material impervious to ink.
6. A prepared compound stencil sheet consisting of two or more sheets of paper
at least one of which is of an open porous nature, and one or more of said sheets being
coated or impregnated with a material impervious to ink.
7. As a new article of manufacture, a prepared compound sheet for use as a stencil
sheet, consisting of two or more sheets, one of which is of an open porous material, the-
other of a thin, close texture, one or more of said sheets being coated or impregnated
with a material impervious to ink, substantially as set forth.
8. As a new article of manufacture, a sheet for use as a stencil sheet, formed of
two or more sheets, one or more of said sheets being of an open porous nature and
one or more of said sheets being coated or impregnated with a substance impervious-
to ink.
Dated this 9th day of July 1896.
THOMAS HEADLY STACKHOUSE.
D. Young & Co.,
11 & 12 Southampton Buildings, London, W.C.,.
Agents for the Applicant.