Improvements in the Manufacture of Copying Paper.
Year: 1890

page_text: Date of Application, 3rd June, 1890-Accepted, 2nd Aug., 1890
COMPLETE
SPECIFICATION.
Improvements in the Manufacture of Copying Paper.
JOHN HAWKE of Lapford House New Barnet in the County of Herts, Gentleman,
do hereby declare the nature of my invention for "IMPROVEMENTS IN THE MANU-
FACTURE OF COPYING PAPER" and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
This Invention has for its object the improvement of sensitive copying paper
whereby it may more readily and universally act upon the chemical constituents of
writing inks and be more cheaply produced, as by the use in combination of the
chemical components of the solution used in my process some writing inks can be
well copied, which would otherwise yield only inferior copies, if any, and by this
chemical combination, economy is effected by the neutralization of acids, which other-
wise cause damage to paper making machinery.
The essential feature of my Invention consists in saturating the pulp of copying
paper during the process of manufacture with a solution of sodic carbonate and ferric
chloride (mixed in such proportions as to cause the cessation of effervescence and
until a slight precipitate begins to form) in the quantities hereinafter described.
In carrying out my Invention I either mix the solution of sodic carbonate and
ferric chloride with the material from which the copying paper is made in the rag
engine or I pass the pulp when it has reached the stage of infinished paper from a
cylinder or roll of paper through a trough or vessel containing the solution but
although I prefer the former of these methods I do not confine myself to either as
the said mixing with the pulp may be effected at any time during the process of
manufacture.
I have found good results to be obtained when the paper is at the time it is used
for copying impregnated with the solution in such quantity as that the paper shall
contain about 600 per cent. in weight of the combined chemicals in the solution, and
I find that the required degree of saturation can be obtained by adding to the water
used in manufacturing five hundred pounds weight of paper two and a half gallons
of the said solution, the chemicals being mixed in such proportions as to cause the
cessation of effervescence and until a slight precipitate begins to form, which pro-
portions I find to be about three hundred grains pure sodic carbonate calculated
Na C.O.
Fe. Cl.
to one pint of ferric chloride calculated at
2 3
, but they vary according
2 6"
to the quality of the latter.
at
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 1
claim is :-
-
The incorporating sodic carbonate and ferric chloride combined in a solution (in
such respective proportions as to cause the cessation of effervescence and until a slight
precipitate begins to form) with the pulp from which copying paper is made or the
unfinished copying paper for the purposes hereinbefore described.
Dated this the Third day of June One thousand eight hundred and ninety.