IMPROVEMENTS IN THE MANUFACTURE OF PRINTING SURFACES
Year: 1853

page_text: PROVISIONAL SPECIFICATION left by Alfred Vincent Newton
. at the Office of the Commissioners of Patents, with his Peti-
tion, on the 16th February 1853.-A communication.
I, ALFRED VINCENT NEWTON, of the Office for Patents, 66, Chancery
Lane, in the County of Middlesex, Mechanical Draughtsman, do
hereby declare the nature of the said Invention for "IMPROVEMENTS
IN THE MANUFACTURE OF PRINTING SURFACES" to be as follows:-
This Invention relates, firstly, to the treating of gutta percha, and
of india-rubber, and of the two gums combined with metals or the
oxides of metals reduced to a granulated state. And, secondly, to the
mode of manufacturing such compounds into moulds or matrixes
and into stereotype plates or printing surfaces.
In manufacturing the composition the gum is heated until soft
in hot water, and it is then passed through the usual grinders or
pressing cylinders. After repeatedly passing the gum through
these grinders, the metallic substance used is dusted on to the
surface, and as it is ground or pressed in more of the metal is
added until the desired quantity has been worked in. The cylinders
being kept heated; the gum is retained at the same temperature.

page_text: during the time of grinding that it had acquired when it was intro-
duced to the cylinders.
The metals or oxides of the metals which have been used with
advantage are peroxide of iron, peroxide of antimony, or the two
combined; also copper oxides and the oxides of lead and zinc. In
cases where the composition is required to keep for a long period it
is desirable to use india-rubber and gutta percha combined.
When the metallic substances above enumerated are used, the com-
position is capable of being worked up again and again for the
purpose of being remoulded; but when this is not required, plumbago
or the flowers of the earths (as clays, ochres, and the crude
metallic ores of zinc, tin, lead, copper, iron, antimony, &c.) may be
mixed in with the plastic gum, and the flowers of the metals proper
and of earthen and glass ware may in like manner be employed to
produce a composition fit for the manufacture of printing surfaces.
The composition prior to being used for taking the impress of any
device, which is afterwards to be printed, is rolled into sheets by
means of heated rollers, and when still in a plastic state it is
brought into contact with the surface, the counterpart of which it
is intended to receive. For this purpose a press somewhat similar
to a copper plate printing press is employed, and supposing
a mould of a form of type is required to be made, the form
is enclosed in a frame which, while it exposes the face of the
type, will prevent the composition from coming in contact with
the furniture and chase, and will gauge the thickness of the
mould, limiting the amount of pressure put on the composition..
The sheet composition to be impressed is laid on a smooth steel
plate, and the form of type having been placed under the pressing
cylinder, the sheet is brought into contact with the two, and gradu-
ally drawn off the steel plate, and pressed into the form of type.
By this gradual depression of the composition, the air will be
pressed from between the contact surfaces, and no defects from air
bubbles will result. The mould thus formed may be passed back-
wards and forwards under the cylinder to perfect the impression, if
thought desirable, and when cold and hard it is ready to receive

page_text: a sheet of plastic material formed by either of the combinations above
mentioned, and impart thereto the counterpart of the device, figures,
or letters which it contains. The operation of making the stereo-
type plate is very similar to that described with reference to the
mould; but it is preferable to place the mould face downwards over
the sheet of composition to form the plate, and to lay a rigid plate
of iron over the mould so as to cause the mould to tip when pressure
is put on it, and so allow of the escape of the air from between the
mould and plastic composition.
In order to dress the back of the moulds and the plates a
horizontal vibrating knife is employed.
For the purpose of making etching plates the following plan is
adopted: A piece of plate glass being provided, the sheet
composition is pressed on its surface, and subjected to heat until the
surface of the gum is melted; it is then allowed to cool, when the
gum will have become solid upon the glass.
To carry these etching plates into use they will be drawn upon,
as is common so to do, upon the composition. In applying the
tools the entire thickness of the compositon, whatever it may be,
will be cut out, leaving the finished line at the lower surface.
In the moulds thus formed plastic material is impressed (as in the
case of the stereotype plate herein-before referred to), and thus a
printing surface is produced. In in like manner duplicates of copper,
steel, or zinc plates, or wood or metal blocks, may be produced.