IMPROVEMENTS IN THE MANUFACTURE OF TYPE OR RAISED SURFACES FOR PRINTING
Year: 1852

page_text: LETTERS PATENT to John Robert Johnson, of Stanbrook Cottage,
Hammersmith, in the County of Middlesex, for the Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF TYPE OR RAISED SURFACES
FOR PRINTING."
Sealed the 9th March 1853, and dated the 19th November 1852.
PROVISIONAL SPECIFICATION left by the said John Robert
Johnson at the Office of the Commissioners of Patents, with
his Petition, on the 19th November 1852.
I, JOHN ROBERT JOHNSON, of Stanbrook Cottage, Hammersmith,
in the County of Middlesex, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF TYPE OR RAISED
SURFACES FOR PRINTING" to be as follows:-
My Invention of improvements in the manufacture of type or
other raised surfaces for printing consists in the use of zinc and its
alloys for this purpose.

page_text: SPECIFICATION in pursuance of the conditions of the Letters
Patent, filed by the said John Robert Johnson in the Great
Scal Patent Office on the 19th May 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
JOHN ROBERT JOHNSON, of Stanbrook Cottage, Hammersmith, in the
County of Middlesex, send-greeting-
WHEREAS. Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Nineteenth-day of November,-in-the
year of our Lord One thousand eight hundred and fifty-two, in the
sixteenth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto iné; the said John Robert Johnson, Her
special licence that I, the said John Robert Johnson, my executors,
administrators, and assigns, or such others as I, the said John Robert
Johnson, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom
of Great Britain and Ireland; the Channel Islands; and Isle of Man.
an Invention for "IMPROVEMENTS IN THE MANUFACTURE OF TYPE OR RAISED
SURFACES FOR PRINTING," upon the condition (amongst others) that I,
the said John Robert Johnson, by an instrument in writing under
my hand and seal, should particularly describe and ascertain thè
nature of the said Invention, and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the
date of the said Letters Patent.
:
NOW KNOW YE, that I, the said John Robert Johnson; do hereby
declare the nature of the said Invention, and in what
manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement thereof (that is to say):
.
=====
My Invention consists in the use of zinc and of the alloys of zinc
which are more fusible_than_this_metal.for_the_purpose-of-casting
type and other raised surfaces suitable for printing. The alloy of
zinc which I prefer for this purpose is that formed by fusing together.

page_text: one equivalent of zinc with one equivalent of tin; that is to say, 33
parts of zinc with 59 parts of tin. When type of great hardness
is required, I employ this alloy alone or mixed with from 2 to 5 per
cent. of its weight of antimony; when type of inferior hardness is
desired, I mix this alloy with ordinary type metal in proportions
varying according to the degree of hardness required; 5 per cent.
of the alloy added to 100 of type metal conferring greatly increased
hardness and durability, and for common printing type I employ
these proportions.
When forming type of the alloy, or of its mixtures, I employ the
ordinary moulds and matrices of the type founders, and the process
or manipulations I employ for casting type are the well known pro-
cesses or manipulations of the letter founders.
I do not confine myself to the use of the particular alloy of zinc
first described; I find that if zinc be redistilled or otherwise purified
it may be used alone for the purpose of casting type; I also find that
type may be made of common zinc and lead, zinc and tin (in other
proportions than those first described), of zinc, lead, and antimony,
of zinc, tin, and antimony (in various proportions), of zinc, tin, and
lead, and of zinc, lead, tin, and antimony in various proportions;
when, however, zinc alone is employed, or when the proportion of
zinc is sufficient to raise the melting point considerably above that
of the ordinary type metal, I find that certain modifications of the
apparatus and of the processes employed are required.
In these cases I form the "jet" or "break" of the mould of porcelain
or earthenware instead of metal usually employed, or I cover the
metallic jet or break of the ordinary mould with white lead ground
in drying oil or putty, and I dry the mould so coated by slowly
heating it so as to interpose an imperfect conductor of heat between
the metal "jet" and the fluid metal to be cast. By these means I
avoid the solidification of the metal until it reaches the "body" of
the mould and the matrix. After casting type for some time in a
mould so prepared, the mould and matrix will be found to increase
in heat until they approach that of the fluid metal. I then lay it
aside, and proceed to cast with another mould and matrix until the

page_text: first las partly cooled; by this inode of operation I avoid the
danger of adhesion between the heated matrix and the fused metal.
During the casting care should be taken that the metal does not
become heated to the subliming point of zinc, and as the oxidation
of zinc and its alloys is rapidly effected at temperatures above the
point of fusion, I cover the surface of the fused metal with a float
of sheet iron, which has an aperture sufficiently large to admit the
ladle used in casting. With these precautions, type of extreme
hardness, for the use of the bookbinders, may be readily manu-
factured of zinc and its alloys melting at a lower temperature than
zinc. I find that when type of great hardness, and containing a
large proportion of zinc, is employed by the letter press printers, it
becomes oxydized under the influence of the alkaline ley used for
removing the ink, as has been already experienced when zinc "rule"
has been employed.
This inconvenience is not found when the alloy of zinc does not
exceed 10 per cent. of the whole, and it may altogether be avoided
by the use of a solution of soap, and particularly of soft (potash)
soap, instead of the usual solution of potash or carbonate of potash
employed.
I have hitherto only alluded to the manufacture of type or other
raised surfaces for printing by casting in the ordinary hand mould
of the founders, but I find that raised surfaces for printing may be also
formed of the alloys of zinc by the "cliché" or "dabbing" process
by adopting the well known apparatus and manipulations at present
einployed; I prefer the alloy of zinc first described for this purpose.
Printing surfaces may also be formed by stereotyping. I prefer
the ordinary alloy of lead and antimony usually employed, with the
addition of from five to ten per cent. of the alloy of zinc and tin
first described, in which case I employ the ordinary apparatus and
manipulations of the stereotype founder. If a larger proportion of
zinc, or of zinc and tin, than that indicated be used, I prefer the boxes
to be well coated with some non-metallic substance to prevent the
adhesion of the tin and zinc to the metal of the boxes, such as white
lead and drying oil, as previously described.

page_text: I claim the use of zinc and of the alloys of zinc inore fusible than
this metal for the purpose of casting printing type and other raised
surfaces suitable for printing.
In witness whereof, I, the said John Robert Johnson, have here-
unto set my hand and seal, this Eighteenth day of May, in the
year of our Lord One thousand eight hundred and fifty-
three.
Witness,
S. Carpmael.
JOHN ROBT. JOHNSON. (L.S.)