AN IMPROVED METHOD FOR PRODUCING DIES OR 'MILLS' FOR ENGRAVING PURPOSES
Year: 1880

page_text: LETTERS PATENT to William Henry Fischer, of 14, Brighton Street, Manchester,
County of Lancaster, for an Invention of "AN IMPROVED METHOD FOR
PRODUCING DIES OR 'MILLS' FOR ENGRAVING PURPOSES."
PROVISIONAL SPECIFICATION left by the said William Henry Fischer at
the Office of the Commissioners of Patents on the 16th April 1880.
WILLIAM HENRY FISCHER, of 14, Brighton Street, Manchester, County of
Lancaster. "AN IMPROVED METHOD FOR PRODUCING DIES OR 'MILLS' FOR
ENGRAVING PURPOSES."
The object of this Invention is to produce in a more economical manner than
beretofore what are known as engraved printing rollers such as those used by
calico printers. The process hitherto employed may be thus described :-The
pattern required to be reproduced is engraved upon a small iron or soft steel roller,
which is then hardened and constitutes a die. By pressing this die ngainst n
similar roller of iron or soft steel a counterpart of the die is formed, the pattern
being reproduced in relief. This roller is termed a "mill" and when hardened it
is used to indent upon a copper printing roller the pattern which it contains, the
same being repeated in rings over the whole length of the roller.
The cost of preparing engraved dies is very great as the work is tedious and the
skill of the practised engraver is required in its production.
In order to transfer a design or pattern to the "mill" without the aid of the
engraver I proceed as follows:-
-
Having prepared a design or pattern in the usual manner I take by means of
photography a negative thereof, and of the exact size required for the reproduced
design. From this negative a print is obtained in sensitized gelatine, and on
removing the soluble portions of the gelatine the pattern remains in relief.
From this gelatine relief I obtain a cast which enables ine to produce a
galvanotype in steel. This galvanotype will constitute the die from which the
"will" is to be produced by pressure in the manner above explained. In this way
it will be seen that I am enabled to obtain dies at a comparatively small cost
however elaborate may be the pattern that is required to be imparted to the copper
printing roller.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Henry Fischer in the Great Seal Patent Office on the
16th October 1880.
WILLIAM HENRY FISCHER, of 14, Brighton Street, Manchester, County of
Lancaster. "AN IMPROVED METHOD FOR PRODUCING DIES OR "MILLS" FOR
ENGRAVING PURPOSES."
The chief object of this Invention is to produce in a more economical manner
than heretofore what are known as engraved printing rollers such as those used
by calico printers. The Invention also applies to the production of embossing
surfaces.
The process hitherto employed in the manufacture of engraved printing rollers
may be thus described:-The pattern required to be reproduced is engraved upon a
small iron or soft steel roller which is then hardened and constitutes a die. By
pressing this die against a similar roller of iron or soft steel a counterpart of the
die is formed, the pattern being reproduced in relief. This roller is termed a
"mill" and when hardened it is used to indent upon a copper printing roller the
pattern which it contains, the same being repeated in rings over the whole length
of the roller.
The cost of preparing engraved dies is very great as the work is tedious and the
skill of the practised engraver is required in its production.
To transfer a design or pattern to the "mill" without the aid of the engraver is
the object of the present Invention.
In the Provisional Specification filed by me at the time of applying for this
Patent I described a mode of producing by the aid of the photographic and electro
type processes tools for impressing printing cylinders with ornairental patterns or
devices.
In perfecting my Invention I have ascertained that the manner of producing
these tools may be greatly simplified, and that instead of making first a "die" and
from this a "mill" to impress the copper printing cylinder I may at once proceed
to manufacture the "mill" without resort to a die when that course is deemed
desirable, as it will be for ordinary work.
I will therefore without further reference to the more elaborate process indicated
in the Provisional Specification proceed to describe my Invention in its completed
form.
The design which is to be impressed upon the printing roller is drawn upon
transfer paper, and from this paper it is transferred to a steel roller or mill blank
which has been previously coated with a material sensitive to light. This coating
I make by preference of a solution of twenty to twenty five, grains of Syrian
asphalte dissolved in one ounce of benzol, to which ten drops of essential oil of
lavender have been added. This solution before being used should be exposed to
the light for about an hour in an unclosed bottle to increase its sensitiveness. The
mill blank is coated by immersing it in the asphalte solution, and it is then dried
in a subdued light, the drying being best effected at night.
When the coating is sufficiently dry the design is transferred thereto by pressure,
and the coated steel roller is then to be exposed to the action of the light from
two to twenty four hours according to the degree of brightness of the atmosphere.
When the coated steel roller has been sufficiently exposed the next operation is
to remove from the roller the transferred pattern which is to be washed off with a
sponge saturated with water or spirit and the roller is then dried. The develope-
ment of the pattern is effected by the use of spirit of turpentine, to which is added
one sixth of its bulk of refined petroleum for delicate designs. The developement
of the pattern should be effected in a subdued light, and after the action of the
turpentine bath the coated roller is to be washed by submitting it to a stream of

page_text: water, after which any adhering moisture is to be blown away, and the roller is
then to be exposed to the action of the light for an hour or two to harden the
asphalte coating.
The roller is now in a condition to receive upon it an electro type deposit of
steel at those parts which the solvent has laid bare. In order however to insure a
firm adhesion of the deposited metal to the steel roller it will be necessary before
submitting the roller to the action of the electro type apparatus to immerse it for a
few seconds in a weak solution of sulphuric acid (say one part of acid to twenty or
thirty of water) in order that the exposed parts of the periphery of the roller may
be made chemically clean. This should be done subsequently to the attachment of
the steel roller to the wire by which it is to be suspended in the electrolyte. The
battery should be of great conducting power but of low intensity.
The electrolyte which I employ is composed of a strong solution of sulphate of
iron and ammonia, and the anodo will consist of a plate of iron which should be
large in proportion to the cathode (steel mill) intended to receive the metallic
deposit. To the iron plate is attached a plate of copper to ensure the electrolytic
action being maintained. On attaching the immersed roller to the negative pole
of the battery and immersing the anode in the electrolyte a deposit of steel will be
obtained on the exposed portions of the surface of the roller. The action of the
apparatus will be continued until the deposit has attained the requisite height for
indenting the pattern upon the copper printing roller to a suitable depth to retain
the printing ink. The steel roller is then cleaned and an impressing die or "mill"
is thus obtained by the combined use of the photographic and electrotype processes
without the aid of the engraver. The roller may, if thought desirable, be tempered
in the ordinary manner before use.
When manufacturing a die proper, according to this Invention, to produce &
"mill" by impressing the pattern thereon I take a steel plate, coat it as described
with respect to the steel roller and submit it to the action of light under a negative
of the pattern or design, and then proceed as abovo explained to develop the
pattern and obtain a counterpart in relief by the electrotype process of the pattern.
The intaglio die thus formed may be used like an ordinary engraved die to impress
the pattern upon a steel roller in relief suitable for transmitting the pattern to the
copper printing roller.
This plan of obtaining the "mill" through the action of a die proper 1 may find
it advantageous to employ when it is required to facilitate the reproduction of a
"mill" carrying a favorite pattern. Flat dies thus made may also be used as
binders' engraved tools, and the "mills" may be used for impressing the embossing
tools used in the book-binding and other trades, which tools have hitherto required
the skill of the engraver for their reproduction.
Having now set forth the nature of my Invention of "An Improved Method of
Producing Dies or 'Mills' for Engraving Purposes," and explained the manner of
carrying the same into effect, I wish it to bo understood that under the above in
part recited Letters Patent, I claim,—―
The combined use of the photographic and electrotype processes as abovo
described for manufacturing dies or "mills" for engraving purposes.
In witness whereof, I, the said William Henry Fischer, have hereunto set my
hand and seal, the Eleventh day of October, in the year of our Lord One
W. H. FISCHER. (L.S.)