Improvements in Printing Surfaces.
Year: 1891

page_text: Date of Application, 8th Sept., 1891-Accepted, 10th Oct., 1891
COMPLETE SPECIFICATION.
Improvements in Printing Surfaces.
We, JOHN GULLALY of No. 223 East 49th Street, Journalist, and LOTHROP
LAMB BULLOCK of No. 17 East 84th Street, Commercial Agent, both of New
York City, in the County of New York, and State of New York, United States of
America do hereby declare the nature of our invention and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement :-
"
Our invention relates to the art of what is technically known as ❝ surface
printing" in which the design is imposed directly upon a flat surface and "takes
or holds the ink for successive printings the surface surrounding the design being
protected from the ink by water as in lithography, which latter has heretofore
been the only practical system of surface printing as distinguished from relief or
intaglio printing.
The disadvantages attendant upon the use of the lithographic stone are however
great, owing to the fragile and uneven texture of the natural stone, the thickness
essential for safety rendering the printing stones heavy and unwieldy as well as
expensive, so that almost from the very first introduction of lithography a
substitute for the stone has been sought, but owing to the peculiar qualities or
properties inherent in the stone has never heretofore been attained. Especially
has it been sought to discover or produce a metallic equivalent of the lithographic
stone, and although large amounts of time, labor and money have been expended
to accomplish this end during the last hundred years, all such attempts have
resulted in nothing of practical value and utility until our discovery and utilization
of the peculiar properties of aluminium and the production of a printing surface
thereof as herein set forth, our invention consisting primarily in a printing plate
or surface composed of substantially pure aluminium; and secondarily in such a
printing plate or surface in which the porosity or absorbent quality of the
aluminium is adapted to the special requirements of the work to be produced by
varying the density of the metal. We have demonstrated practically that our
aluminium printing plates or surfaces meet all the requirements of the art of
surface printing as heretofore conducted upon the lithographic stone, while
affording many advantages over the latter.
We have thus discovered, utilized and practically applied a property and a
possibility of aluminium not heretofore known or utilized, that is to say, the fact
that a plate or surface of substantially pure aluminium may be so prepared as to
afford peculiar absorbent and other inherent qualities which, while they may not
be the same, are the substantial equivalents of those which have heretofore
rendered the lithographic stone the only material suitable for surface printing
while the superior resistance of the aluminium plate to chemical action and
oxidization, its elasticity and greater strength, durability and cheapness, as well as
the ease with which it may be prepared and manipulated render it superior to the
lithographic stone and of great practical utility and value to printers and to the
public generally so that it is certain eventually to supersede the stone (even were
the known natural supply not limited as it is) and to cheapen as well as to improve
the products of the art of surface printing.
We are aware that numerous attempts have heretofore been made to substitute
zinc for the lithographic stone, but such attempts have never been successful in a
commercial sense since, in practice so few perfect impressions can be obtained from
the design when imposed upon a zinc surface before the latter becomes fouled with
ink that the cost of the product is prohibitory and the only use for which zinc
plates are at present utilized is simply as transfer or storage plates for designs to bę

page_text: preserved, in lieu of the use of heavier, more bulky and expensive stone for this
purpose as heretofore.
Zinc plates practically afford no better results than might be obtained upon
almost any other smooth surface, there being a deficiency in that absorbent quality
which enables both the stone and applicants aluminium printing plate to retain the
design unimpaired through successive printings in the presence of moisture on
the surface surrounding the design.
Owing to the imperfect porosity of the zinc plate the design has a tendency to
spread over its surface, if printed from repeatedly, which it is difficult to counteract
while the oxidization, which is augmented by the presence of the water that is used
to prevent the adhesion of the ink to the surface surrounding the design,
rapidly renders the zinc plate useless, the oxide taking the ink and causing the
plate to foul or grease," as it is technically called.
66
Besides this the zinc plates weigh about three times as much as our aluminium
plates of the same size, and thickness, and cannot be made and used as thin as our
aluminium plates, even were it possible to print successfully from the zinc surface.
On the other hand our aluminium printing plates can be successfully made and
used of a thickness of less than one sixteenth of an inch, with the double
advantage of reducing the cost and weight to the minimum and of rendering the
plate flexible so that by adapting itself more perfectly to pressure during
"pulling" of an impression a more perfect, uniform result is obtained.
Another important practical distinction between the zinc plate and our aluminium
plate consists in the fact that zinc is especially subject to the attack of acids, so
much so that it is unsuitable for use with certain colored inks even for relief
printing; whereas our aluminium plates are absolutely proof against all but the
strongest acid (hydrochloric) under ordinary conditions, and do not tarnish or
deteriorate under atmospheric action alone as zinc does.
An important feature of our invention and one which distinguishes clearly the
difference between our improved plate and the stone or zinc plate, is that we are
enabled to regulate the density of the plate, and consequently its porosity, during
its manufacture, with relation to the work to be performed on it. Thus a finer
grade of work can be produced on a plate of comparatively greater density than
that desirable for work of a coarser nature, and this feature of variable density
may in a measure be considered independently of that of the preparation of the
surface by graining as hereinafter set forth. It is true that the density of the
plate and the coarseness or fineness of the graining imparted to the surface both
act in conjunction in affecting the quality or grade of the plate, but the variation
in density is of paramount importance in regulating the actual degree of porosity
upon which the absorbent qualities of the plate mainly depends.
It is well known that the lithographic stone is especially liable to crack or break
while subject to pressure during the pulling of an impression, and that this danger
increases as the thickness of the stone decreases. We not only entirely avoid this
difficulty by the use of the aluminium plate, but we are also enabled to employ
such a plate so thin as to be practically a flexible plate which will adapt itself
perfectly to the pressure, and thereby afford a more perfect transfer or impression
than can be obtained from a rigid unyielding surface like that afforded by the
stone when of sufficient thickness and strength to resist fracture under like
conditions or of the zinc plate either.
Since aluminium of average density is lighter than the lithographic stone the
greater ease and convenience of manipulating a thin sheet or plate of aluminium
as compared therewith is obvious, especially when it is considered that a sheet of
aluminium of any width and length one sixteenth of an inch or less in thickness is
sufficient to afford a surface printing plate answering all practical purposes,
whereas only the very smallest lithographic stones can be used when of a thickness
of less than two inches.
Another important distinction attained by us is that by our improved process of
surface printing on aluminium we can produce on a single plate, and at a single

page_text: printing, a design or impression of practically unlimited extent as compared with
lithography which is limited to the production of prints or impressions not
exceeding 4x5 feet in superficial area, larger prints, as maps &c. being printed in
sections from different stones. Again by our improved process we can print from
curved or cylindrical plates, thus enabling us to utilize cylindrical power printing
presses to attain continuous surface printing,-
-a result heretofore attempted but
never successfully attained.
As far as the practical embodiment and use of our invention is concerned it is
immaterial how our improved printing plate is constructed provided the printing
surface is of aluminium, the essential feature in this respect being a plate or layer
of aluminium of sufficient thickness to afford the peculiar qualities of porosity &c.,
inherent in the metal. But as these qualities of the metal are inherent in a layer
or plate of almost imperceptible thickness the quantity of aluminium necessary
for the formation of a suitable printing surface is comparatively small, and the
aluminium surface may therefore be obtained upon another cheaper metal by
electrolysis, or a thin layer of aluminium may be mounted upon or reinforced by a
backing of metal or other suitable material applied in any well known manner.
Another important advantage we attain by the use of our improved printing
surface of aluminium as compared with the use of the lithographic stones is that
we are enabled to make the printing surface conform to any desired curvature or
to make it completely cylindrical, the latter form opening the way to an entirely
new developement of this class of surface printing, since all the advantages of
speed, economy &c., attendant upon rotary cylinder printing, as compared with
flat or plate printing, may be combined with the superior results and effects
heretofore attainable exclusively, at comparatively great expense, by lithography.
In the accompanying drawings we illustrate the embodiment of our invention in
practical form, although we do not confine ourselves to any special form or con-
struction of parts, since it is obvious that various modifications in detail may be
introduced without departing from the essential spirit of our invention.
Figure 1, is a plan of a flat printing plate with aluminium printing surface upon
which a design has been imposed;
Figure 2, an edge view of Figure 1.
Figure 3, a sectional view indicating a plate of metal or other suitable material
provided with a facing of aluminium deposited by electrolysis, the thickness of the
aluminium being exaggerated for purpose of illustration.
Figure 4, a similar view showing a sheet of aluminium backed with metal or
other suitable material.
Figure 5, a sectional view of a cylindrical printing roller formed with a printing
surface of aluminium.
The printing plate A, as a whole, may be formed or built up in any suitable or
well known manner, provided it is formed with the facing a, of aluminium. Thus
the facing a, may be afforded by the use of a comparatively thick plate a', of the
aluminium attached to a platen or base h, or a comparatively thin layer (a',
Figure 3) of aluminium may be applied to the base or platen b, by electro-
deposition.
Again a thin layer of aluminium may be secured to the base or platen b, by any
suitable mechanical means of attachment as illustrated in Figure 4, or to the
surface of a rotary printing roller 6', as indicated in Figure 5, or a simple thin
sheet of the metal may be used for the printing plate, which form is especially
effective in some forms of printing, as for instance for use in the hand press.
In all of the constructions indicated as well as in the case of others that may
be desirable to comply with the requirements of special use, the essential feature
is the layer or plate a', of aluminium affording a printing surface a, of that metal,
and all questions of construction and application are secondary to that.
The density of the sheet or plate of aluminium may be regulated in its manufac-
ture by any suitable means, as by alloying, compression, annealing, or other well
known manner according to the degree of porosity required.

page_text: The surface of the aluminium plate is either grained or polished according to the
technical character of the work to be produced, the aluminium surface being
adapted like that of the stone to receive the design either by direct drawing,
crayon, transfer, engraving or etching as heretofore practised, and substantially
the same processes being resorted to in fixing the design and making ready for
printing.
Ordinarily however, graining is preferable for drawing and transfer work, and
herein the treatment of the aluminium plate differs from that of the stone which is
invariably polished for transfer work, and only grained for what is known as
crayon work. The ink taking or holding quality of the plate on the other hand is
regulated by the degree of coarseness or fineness imparted to the surface of the
aluminium in graining, as well as by the density and consequent degree of porosity
imparted to the material, and may thus be adapted to the requirements of the
character of the work to be performed or of the results sought to be attained in
the prints or impressions a feature not attainable in the use of stone.
In use the surface of the plate not occupied by the design is kept moist with
water in the usual manner to prevent the adhesion of the ink excepting to the
absorbent surface of the design.
It is to be understood that while we use and claim substantially pure aluminium
for our improved printing surface we do not limit ourselves to the strictly pure
material as any compound plate in which aluminium predominates might be used
with more or less success without departing from the essential feature of our
invention.
"
We do not seek to cover the use of a metallic plate broadly for what is known
in the art as surface printing.
It will be understood that the term "aluminium" is herein used in its ordinary
sense, that is, as describing aluminium of commerce and not necessarily pure
aluminium.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is,
The herein described plate for use in surface printing having a surface of
aluminium on which any suitable design has been placed, substantially as
described.
.
1001
APLICA GIN LO
1001
FELL & WILDING,
i, Queen Victoria Street, London, E.C., Agents for the Applicants.
FELL & WILDING,
, Queen Victoria Street, London, E.C., Agents for the Applicants.