Light-weight Embossing Dies with Atmospheric Register for Letter-press Printers.
Year: 1898

page_text: Date of Application, 10th Jan., 1898
Complete Specification Left, 1st Sept., 1898-Accepted, 3rd Dec., 1898
PROVISIONAL SPECIFICATION.
Light-weight Embossing Dies with Atmospheric Register for
Letter-press Printers.
ROBERT JAMES COPAS, 41, Gray's Inn Road, London, W.C., Designer, Engraver
on Wood, and Photo-Etcher, do hereby declare the nature of this invention to be
as follows:-
This is an invention especially for enabling letter-press printers to readily do
embossing on paper, card or other suitable material with letter-press printing
presses and machines.
It consists substantially in the invention of hard, flexible, light-weight dies,
with their matrices; and in the application of atmospheric pressure to register
the dies and matrices in the printing press. It includes also the combination of
several matrices in one forme, in the same way as wood blocks or movable types,
embossing on one sheet of paper or card, without necessarily having to make
special dies or matrices for the job in hand, without spoiling the work by
embossing the edges of the matrices or dies on the paper or card, and without
destroying either dies or matrices when the job is finished, as my dies and matrices
like type, to be preserved for future use.
are,
I engrave an original matrix in wood or metal, and make a nickel-faced or steel-
faced electrotype (hereinafter called "A") from it. The original matrix I now
bevel, to prevent its edges showing in subsequent work, and make another
electrotype (hereinafter called "B") from it.
I now make from the electrotype matrix A" a die, which must be hard,
flexible, and light in weight. I have invented several ways of making a die
having all these special qualities; they are as follows:-
1. By the application of celluloid to this special purpose; with hydraulic or
other pressure, press celluloid into the matrix "A in the usual way in which
celluloid is worked. This form of die needs no backing to support the lines.
2. By pressing sheet celluloid into the matrix "A" and afterwards backing it,
i.e. filling in its lines, with a suitable cement; which I describe more fully
under (4) the metal skin die.
3. By the application of vulcanite to this special purpose. It is either solid
vulcanite, the material being pressed into the matrix A" and baked in the
usual way under pressure; or it consists of a vulcanite skin, backed.
$6
"
4. I press thin copper or other suitable metal into the matrix "A" with
hydraulic or other pressure, back it with a suitable cement, and bake it. To back
the metal skin; I lay the matrix A upon its back with the metal skin still
in it, as it comes from the press; and work into the lines of the skin a suitable
cement (consisting for instance of 1 part white lead, 1 part red lead and 1 part
mastic varnish). I now take the cemented metal skin out of its matrix
and bake it for two hours or more in a suitable drying oven, with a current of
heated air. It then becomes hard, yet flexible. Or I back the metal skin with
celluloid, or vulcanite.
$5
A,"

page_text: "
5. Consists of a skin of copper formed by electro-metallurgical deposition upon
the matrix A" after treating it with a suitable conducting composition; or I
make the skin in any other way usual in electro-metallurgical deposition, as for
instance by a wax mould of die No. 4, I then back the copper skin with a specially
suitable backing as before.
Whichever way I adopt to make this special kind of die which I require, when
it is made, I mount it on thin hard wood or card or other suitable material, and it
is ready for the printing press.
The matrix "B" is now set in a printer's forme, and inserted in the printing
press, the platen of which is covered with card firmly attached to it. The faces
of the die and of the matrix "B" are rubbed either all over or in parts with a little
litho varnish, wax or other suitable material. The die is adjusted into close
contact with the matrix "B"; the pressure of the atmosphere keeping the die
(in the vertical or other position it is in, in the press) closely attached in perfect
register, to the matrix "B." The back of the die, and the platen card are now
pasted or glued over with a suitable adhesive material; the platen is moved
forward on to the forme with pressure, and when the paste or glue is dry, I move
the platen away from the forme, and bring with it the die which adhered to the
matrix. The faces of the die and matrix "B" are cleaned of the material which
assisted in holding them together, and this done, they are now ready for the press
to be fed with paper or card for embossing.
Dated this Tenth day of January 1898.
Light-weight Embossing Dies with Atmospheric Register for
Letter-press Printers.
I, ROBERT JAMES COPAS, of No. 41, Gray's Inn Road, in the County of London,
Engraver on Wood and Photo-Etcher, do hereby declare the nature of this inven-
tion 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 reference to improvements in and relating to dies for
embossing on paper, card or similar material and is especially designed for use
in letter press printing presses and machines and also relates to the method of
their application to same.
Heretofore the method of making and using counter dies on printing presses con-
sisted in inserting the matrix or engraving die in the press and then forming
on the platen a plastic material such as gutta-percha papier-mache, leather, card
board, plaster, sealing wax or other similar substances and impressing the matrix
upon such substance while the latter was warm or wet and then trimming the edges
with a knife. This method has many disadvantages varying with the substance
used. The gutta percha squeezes out at its edges during the work of embossing
requiring frequent retrimming to prevent the edges of the die shewing upon the
work embossed. The gutta percha being soft at the point of impact the resistance
of the paper, first crushes down the projections of the raised portions of the gutta
percha, and then by continuing the pressure in the ordinary course of the embossing,
the matrix pressing through the paper, forces them up again, so that the gutta
percha counter die is destroyed and remade every time a sheet of paper is embossed,
involving an enormous loss of energy in driving as well as straining the press
itself. Other substances hitherto used for counter dies, either require an amount

page_text: of pressure which the press is unable to give, or they are soft like the gutta percha,
or brittle as in the case of plaster, or shrink as in the case of leather, the latter
being impressed whilst wet and they become loosened from the platen during the
embossing and none are successfully detachable after the work is done with a
view to use upon a future occasion. In the case of electro counter dies, these not
only require special mechanical appliances to hold them to the platen of the press
but their rigidity combined with their shrinking during the cooling of the metal,
with which the copper shells are backed, render it impossible to obtain a perfect
register.
Now my invention consists substantially in the production and use of dies and
matrices which are hard, flexible and light and also in the utilization of atmo-
spheric pressure to secure a perfectly accurate register of the dies and
matrices in the printing press or machine. Dies and matrices con-
structed according to my invention possess the three qualities indispensable
in a counter die intended for use on an ordinary printing press or machine.
Firstly they are hard and tough without being brittle so that they cannot break or
be crushed out of shape by. the work. Secondly they are flixible so that they can
be instantly adjusted to get the register; their ductility insuring the retention
of their proper shape and place upon the platen or cylinder while in use; and
thirdly they are light in weight so that they will not, as frequently happens in the
case of leaden or electro dies, fall off or shift down by gravity, while registering
them on the platen or cylinder, nor tend to fall off during working. Furthermore
several dies can, be set up together in the same forme, enabling embossing to be
done on a larger scale than hitherto, more in the manner of magazine printing,
without the printer having to make a counter die in every case. The dies can
also be readily affixed to the platen or cylinder or detached therefrom and stored
away for future use.
An original matrix or female die is engraved, square gravers and square router
tools being used so as to make V shaped cuts on boxwood, engravers' surface
metal, zinc or brass and one or more electros (hereinafter called "A") taken from
it; the sides of the ✓ shaped cuts being at right angles to each other so as to
prevent sticking and to facilitate the delivery of the paper or card from the
matrix. The electro should have a thick copper shell, and be, for finest work,
nickel or steel faced. The original matrix is now bevilled to prevent its edges
shewing upon subsequent work and one or more electros made from it (hereinafter
called B) but not necessarily with a thick copper shell or nickel or steel faced.
When not more than one female die is required it is engraved on zinc or brass and
used without electrotyping.
From the electrotype "A" or from the original zinc or brass matrix is now
made a male or counter die (hereinafter called the "die") which must be hard
so as to wear well and not be crushed out of shape by the work of embossing, and
which must also be sufficiently flexible or ductile to avoid the difficulty there is
in registering a pair of unyielding dies, and still more flexible or ductile in the
case of dies which have to be bent to cylinder machines.
I will now proceed to describe the construction of the dies which for the purposes
of this invention are formed either of solid celluloid, a skin of sheet celluloid, a
skin of pressed copper or copper foil, or of a copper shell obtained by electro
metallurgical deposition.
For the preparation of the solid celluloid die, which I call die “No. 1," I press
thick sheet celluloid, or in the case of very deep work, two thicknesses of thick
sheet celluloid into the matrix, with heat, using a hydraulic press heated with
steam, such as is used for working celluloid; or I may use a sufficiently powerful
bookbinders' blocking press having both its platen and bed plate heated by
Bunsen burners. I first ascertain that the platen and bed plate are at the proper
temperature (300° Fahr. being a useful working temperature) and then
place the matrix on the bed of the press with the engraved side up. Upon the

page_text: matrix I place the celluloid, cut rather larger than the matrix, and upon the
celluloid a steel plate of about 8th of an inch thick and slightly larger than the
celluloid, to prevent the latter sticking to the platen. Where necessary parts of
the matrix are underlayed with paper to get more pressure upon such parts and
thereby bring up the detail of the work. If a steam heated celluloid press be used
I cool the die in the usual way whilst still in the press, but if a blocking press be
used, I pass it quickly whilst hot with the matrix to a cold copying or other
suitable press, quickly put on the pressure and allow it to cool. When the die is
sufficiently cold I rub it with camphorated oil to prevent it drying out of shape;
then mount it upon thin card of good quality or a suitable flexible fibrous material
with a cement consisting of gelatine dissolved in acetic acid with heat or with any
of the acid gelatinous cements of commerce. To overcome any difficulty in
pressing the thick celluloid into the matrix, by reason of the depth of work and
the slowness with which the celluloid becomes heated all through to be uniformly
plastic I expose two or more sheets of medium, or even thin celluloid, for a few
seconds to the action of acetone vapour and press them together into one sheet,
pressing them and making the die in one operation. It is unnecessary to treat the
bottom sheet with acetone to cause it to adhere to the sheet above it, treatment of
the latter being sufficient and further its under surface might possibly be affected
and caused to stick to the matrix. When more than two sheets are joined together
it is unnecessary to treat the top one with acetone, unless it is intended to mount
them upon card in one operation when making the die, in which case treatment
of the top sheet with acetone, will cause the celluloid to adhere firmly to the
card without gelatinous cement. When two sheets only are joined together for
subsequent cold cementing to fibre, I place a thin sheet of paper on the top sheet
which has been treated with the acetone and press them together in the press in
making the die; then wash off as much as possible of the paper; the paper
remaining embedded in the celluloid helping to hold it more firmly to the fibre
when cementing them together. On completion of the die as above, the edges
are trimmed or cut square with a circular saw and bevilled with an iron bevilling
plane and shoot block.
Dies as above described are intended for embossing bold heavy work on thick
paper or card on platen presses.
In preparing the sheet celluloid skin die, which I call die No. 2, intended for
embossing paper or thin card, I treat the sheet celluloid in the same manner as
described above, using thick strawboard instead of the steel plate to press the
celluloid down into the work. After the skin is cold and the strawboard removed
from the top of the die the lines in the back are filled in with a suitable cement,
such as bichromated fish glue, a flat knife or piece of wood being used to slowly
and evenly push the glue along the back of the die, care being taken to exclude
all air from the lines, and to remove all superfluous fish glue, leaving only the
lines filled in. It is then exposed to the light to harden. If the lines are not
sufficiently filled, consequent upon the shrinkage of the glue in drying, the opera-
tion is repeated. When dry the backed skin is mounted on card or a suitable
flexible fibrous material with an acid gelatinous cement. The mounted
die is then trimmed and bevilled as before. In this die I use thick sheet celluloid
for specially deep work, medium for work of an average kind, and thin for dies
not intended to be very much used; the "thick" being 22nd of an inch in thick-
ness, the "medium" half this thickness and the thin one third the thickness
of the medium." The fibre used is about and of an inch thick for cylinder
machines and about 12th of an inch for platen presses. To make the pressed
copper skin die, called No. 3, I press sheet copper or copper foil of about the
thickness of the shell of an ordinary electrotype, with a hydraulic or blocking
press into the matrix "A" in a cold state. The matrix is placed on the press,
the copper foil upon the face of the matrix, and two or more thicknesses of straw-
board above the copper foil. These are then heavily pressed. Or I fix the matrix
**
66

page_text: on the press with glue and paper; adjust the die No. 1 in the matrix, glue paper
on the platen and glue the back of the die, then by pressure I transfer the die to
the platen. When the glue is dry I place the copper foil on the matrix and
press it into the work by means of die No. 1. To back the metal
skin I lay the matrix A upon its back with the metal skin still in it
as it comes from the press and work into the lines a cement consisting of equal
parts red lead and mastic or copal varnish, removing all superfluous cement from
the back. After wiping clean the face of the skin it is placed in a suitable
chamber wherein it is exposed to a current of heated air for two hours or more
until it is hard yet still flexible or ductile. I sometimes use a cement consisting
of rather less than one part red lead and rather more than one part celluloid
varnish or celluloid dissolved in acetone to the thickness of cream. I fill the lines
with this cement and dry in a room heated to between 70 degrees and 80 degrees
Fahr. I then mount it on card or fibre, as before or back it with celluloid. To do
the latter I use the untrimmed celluloid die No. 1 or No. 2, the latter if intended
for use on cylinder machines being mounted upon thin paper. Either of these
dies I rub over rapidly with a piece of clean old linen, saturated with acetone,
covering the whole of the surface as evenly and with as little solution as possible.
The celluloid die is inserted in the back of the copper shell if necessary first
coating the latter with celluloid varnish and allowing it to dry and then press
with heat as before and allow to cool under pressure. By these means the celluloid
is made to adhere tenaciously to the copper shell. In the case of large dies I
expose the celluloid to the vapour of acetone in a closed airtight box for about a
minute until the surface of the celluloid is slightly softened. It is then immedi-
ately placed in the copper shell which is resting in the matrix and pressed hot as
before. By these means the celluloid fuses to the metal at a temperature at which
the celluloid not affected by the acetone is plastic only. I then mount the skin
upon card or fibre with acid gelatinous cement as before and trim up its edges
with shears or a card cutter, if with the latter the copper face of the die should
be upwards so that the knife coming down shall not only cut through the copper,
but also turn its edges over and down into the fibre, thus forming a metal pro-
tection to the edges of the cement which is between the copper and the fibre.
This form of die is quickly made and is designed for simple shallow work, having
bold lines and little detail, and for use by printers who desire a comparatively non-
inflammable die.
<<
""
The electro copper shell die which I call No. 4, I make by electro-metallurgical
deposition upon the matrix A after coating it thinly with melted wax and
blackleading it over; or I make the shell by electro-metallurgical deposition
upon a wax mould made by cold pressure of dies Nos. 1, 2, or 3. This die is
backed and mounted in every way the same as die No. 3 and is intended for best
work upon cylinder machines and is comparatively non-inflammable.
For embossing on cylinder machines soft paper and cards or other suitable
materials are used to avoid creasing and in all cases the dies must be absolutely
clean and free from grease or they cannot be successfully cemented together.
To readily ascertain the accurate register of colour blocks, which are subse-
quently to be embossed, a line is engraved on the original matrix the exact size
the block is to be when mounted, and is reproduced when making the die and the
colour blocks. This is done by inking the matrix, taking a proof therefrom,
transferring it to wood or metal and preserving the line during engraving and
mounting. The blocks dies and matrices are then all carefully planed on their
sides so as to plane away this line and no more. The colour printing is first
done, finishing with embossing.
In the accompanying drawing is shewn the air tight box in which the celluloid
is exposed to the vapour of acetone.
Fig. 1 is a sectional elevation, the upper portion being slightly raised from the
base of the box.

page_text: Fig. 2 shews a suitable form of carrier for inserting and removing the celluloid
from the box.
Similar letters of reference indicate like parts in the two figures.
a, a, are the sides of the box composed of wood or other suitable material; the
base plate to which is secured the pad c of flannel or other suitable material to be
saturated with the acetone; d is a layer of rubber for sealing the joint when the
box is closed; e is the top of the carrier, of which there may be several, forming
the top or cover of the box when closed; f are strips of wood secured to the sides
of the box and forming the grooves in which the carrier slides; 9 is a strip of
rubber attached to the top of the carrier to seal the joint when the carrier has been
let down into the box and fastened by the clips h, the base plate being secured to
the body of the box by similar clips, and additional support being provided by
the studs which take into the holes or slots ². These clips are held in their
closed position by studs or projections i taking into holes or indents j; k is the
wire work forming the body of the carrier; l is a strip of wood attached to the
bottom of the wire work of the carrier to prevent its being drawn entirely out of
the box when it is desired to inspect or remove the celluloid under treatment.
The modus operandi is as follows:-The carrier is raised to its highest point
& the celluloid inserted between the two portions of the wire work which are
then closed and the carrier allowed to drop into the box where it is secured in
position by the clips. The pad c having been previously saturated with acetone
the celluloid under treatment is subjected to the action of the vapour thereof for
the necessary period when the clips are opened and the carrier raised to its highest
point and the celluloid removed.
The following is the method of using the dies and obtaining a perfect register;
The mounted electro (female die B) is fixed in the chase in the usual way and on
it a little strong litho varnish is rubbed. The male die is pressed face downward
into close and rigid contact with the electro, a little French chalk is rubbed into
the fingers and knuckles to prevent them sticking to the back of the die while
pressing it down. The male die is backed with soft thin paper covered with a
thin layer of fish glue to permit of the easy detachment of the die from the platen
when the work is done. Sufficient pressure must be put on with the fingers and
knuckles when pressing the male die down or the die will work loose and the
register be lost. Breathe well on the back of the die, or rapidly wipe it once with
a damp sponge or rag, being careful not to wipe off the cement. This will make
the back slightly tacky or sticky. Insert the chase and die in the press, turn the
fly wheel until the platen presses heavily, but not too heavily, on the two dies.
Then turn the fly wheel the reverse way so as to draw the platen slowly away
from the chase; the male die will come away from the female die and adhere
firmly and in perfect register to the platen. The pressure of the atmosphere and
of the fish glue on the back of the male die and which holds it to the platen is
greater than the resistance of the atmosphere and varnish holding the two dies
together. To remove the male die after use, insert a thin knife between the die
and platen. This will split the soft thin paper and the die will be detached
uninjured.
The method of fixing the dies to cylinder machines is the same as for platen
presses, excepting that the back of the die is made with a sufficiently bevilled
edge to allow of the cylinder rolling on to it without pushing it out of register,
the die being held firmly down until the cylinder is well on the die. The cylinder
is then rolled on the die until it has securely taken it up. Or the cylinder may
be first moved forward until it is above the die without being in contact with it
and then let down and rolled as before. It is advisable to fix only one die at a
time,
In my Provisional Specification filed in respect of this application one of the
modes of preparing the dies is stated to be by the use of vulcanite, but I find that
it does not give satisfactory results and further that its proposed use for this
purpose is not novel and original and I therefore do not claim it as of this invention.

page_text: 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. The use of celluloid in the manufacture of embossing dies for use in letter
press printing presses or machines, substantially as described for the purposes
specified.
2. In the manufacture of embossing dies the use of a skin of celluloid to form
the face of the die with or without a suitable backing such as bichromated fish
glue substantially as described for the purposes specified.
3. In the manufacture of embossing dies the use of a skin of pressed copper or
copper foil to form the face of the die with or without a backing of celluloid or
of cement such as celluloid varnish and red lead substantially as described for the
purposes specified.
4. In the manufacture of embossing dies the use of an electro type copper shell
die, formed by electro-metallurgical deposition upon a matrix or upon a wax
mould with or without a backing of celluloid or of cement such as celluloid varnish
and red lead substantially as described for the purposes specified.
5. In the manufacture of celluloid embossing dies the treatment of the celluloid
by acetone vapour substantially as described and shewn for the purposes specified.
G. The manner of fixing the male and female dies on the platen and press
respectively by the use of a varnish dissolvable in oils to hold the die to the
matrix and the use of a cement or glue dissolvable in water to hold the die to
the platen or cylinder substantially as described for the purposes specified.
7. The use of a cement such as celluloid or mastic or copal varnish (mixed with
red lead or other similar substance) or bichromated fish glue for filling in the lines
in the backs of the faces of embossing dies, substantially as described for the
purposes specified.
Thatod th 17th Jan of
1000
JAMES G. STOKES,
Agent for the Applicant, 8, Dane's Inn, Strand, London, W.C.