F?lb. 16, 1943.
w_ T‘ HAGELlN
2,311,047
LITHOGRAPHIC PLATE AND PROCESS OF MAKING THE SAME
Filed Dec. 6, 1940
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2,311,047
LITHOGRAC PLATE
I“ G
W
PROCESS OF
E SAME
T. Hagelin, Chicago, Ill.
Application December 6, 1940, Serial No. 368,753
15 Claims. (Cl. 41-415)
This invention relates to a lithographic plate
method of producing the same upon which a
and a process of making the same. More parvery ink-receptive image may be impressed
ticularly, this invention relates to a process of
either by means of direct contact or by means
producing a lithographic plate having a surface
of photolithographic processes.
that is very receptive to greasy films such as may 5
A further object of this invention is the pro
be applied thereto by crayon, lead pencil, grease
vision of a metal surface coating which is sub~
ink, and the like or by a suitable stylus through a
stantially non-oxidizable even though exposed to
tracing sheet such as carbon paper or a typethe atmosphere under conditions normally pro
writer ribbon.
moting oxidation.
A plate, to be useful in ordinary lithographic 10
A still further object of this invention is the
work, should be one that is treated in such a
provision of a new etch solution which may be
manner that the surface thereof is adapted readily to receive a grease coating or ?lm such as may
be made through a typewriter ribbon or by pen-
used for the treatment of lithographic plates.
Further additional objects will appear from
the following description, the accompanying
cil, crayon, or other drawing or tracing instru- l5 drawing, and the appended claims.
'
ment that is capable of depositing a greasy ?lm
In accordance with one embodiment of this
on said surface when contacted therewith. The
invention, a lithographic plate may be prepared
character of the surface should be such that after
from a metal sheet by subjecting one surface of
desired markings have been produced thereon,
the sheet to a graining treatment, and then sub
the portions of the surface not coated with the 20 jecting said surface to the action of an alkali
markings or grease ?lm may be subjected to a
earth metal oxide and silica in the presence of
treatment whereby those portions of the surface
water. These compounds apparently react with
will be rendered ink-repellent while the coated
the metallic surface of the lithographic plate to
portions remain very receptive to greasy subform a deposit or coating which is extremely re
stances such as lithographic ink. Consequently, 25 ceptive to markings which may be impressed
when the lithographic plate having an image imthereon by a grease-containing stylus such as
pressed thereon is passed under a roller contain-
ing a grease ink, the ink will adhere only to that
portion of the plate to which the grease ?lm or
markings have been applied and a reproduction
01' the markings may be transferred directly to
the surface to be printed or to a cylinder having
a rubber blanket which in turn transfers it to the
desired surface in accordance with the common
pmtlce. It is therefore important in the lithographic art that lithographic plates have a surface which at one time is strongly receptive to
markings which may be produced by greasy matcrials. but which surface is also of such a chardeter that it may be treated to render it greaserepellent except in those portions of the surface
to which the greasy film or markings have been
applied.
It is an object of this invention to provide an
improved lithographic plate which is capable of
readily receiving a greasy ?lm from any sort of
a drawing instrument, stylus or stencil capable
of depositing on said surface a grease-containing
?lm in selected areas./
A further object of this invention is to provide
a continuous process of preparing a lithographic
plate having the above indicated desirable characteristics.
A further object of this invention is the provision of a ?exible lithographic Plate and a
a crayon‘ or lead pencil, or which may be im
pressed thereon through ordinary carbon paper
or a typewriter ribbon. The deposit renders the
30 surface of the metal treated very resistant to
oxidation and the treated plates may be stored
for long periods of time,
The process of producing lithographic plates
of this invention may be continuous. In accord
35 ance with one embodiment of this invention, a
continuous thin metal strip is passed under a
revolving wire brush in order to remove foreign
material from one surface of the strip, and to
impart a desired grain thereto. The resulting
40 strip is then subjected to a scrubbing or brush
ing action in the presence of substantial quan
titles of a mixture of lime, ?nely divided silica,
and water. During this scrubbing action a de
posit or coating forms on the surface of the
45 metal sheet which is subsequently brushed and
washed with water and thoroughly dried. The
deposit or coating survives the subsequent wash
ing and drying operations and is of such a nature
that the surface of the resulting metal is very
50 receptive to grease markings imparted by con
tact or to other images produced in accordance
with well known photolithographic processes.
The thus treated metal sheet may then be
marked, scored, cut and packaged as desired.
55
It will, or course, be recognized that‘ any type
asiaoav
of metal plate ordinarily used for lithographic
dimensions indicated above. ‘The metal surface
work may be employed in carrying out this in
of the strip l2 has been, prior to the time that
vention. While I prefer to use aluminum or
it is rolled into the roll 10, treated with a wire
zinc, it is within the scope of this invention also
brush, in order to remove foreign matter from
to employ stainless steel, Monel metal, or other
the surface of the metal and to provide a. suit
metals or alloys which have been used in the
able roughness or grain to the surface of the
lithographic art. If desired, a. thin metal sheet
strip to be treated.
may be employed which has a. paper backing ad
The strip I 2 having the grained surface is
hesively secured thereto. This paper backing
pulled continuously from the roll I0 by means
is preferably waterproofed and secured to the 10 of the drawing rollers it under a spout 20 of a
sheet metal with a waterproof adhesive, so that
receptacle 22 having contained therein a mix
subsequent contact of the resulting plate with
ture 24!, which is deposited on said strip. The
water during treatment and during use will not
mixture 26 preferably comprises about two parts
cause separation of the paper and metal sheet.
by weight of calcium oxide, about two parts by
Also, while it is preferred to employ a mixture 15 weight of finely divided silica, and about eight
of water, lime and ?nely divided silica as the
parts by weight of water. A small amount of
treating agent for the plate to form the desired
benzoyl blue may also be added thereto in or
grease-receptive deposit, it has been found that
der to provide a desired whiteness to the coated
other alkali earth metal oxides may be substi
surface of the resulting product. The mixture
tuted for the lime. Suitable substitutes are the 20 ‘2% within the receptacle 22 is continuously stirred
oxides of barium, magnesium, and strontium.
by a paddle 26 operated by means (not shown)
Under certain conditions, various silica-contain
through a belt 28. By this means, the ingre
ing abrasives may be substituted for the silica,
dients in the mixture 24 are kept in uniform
or other ?nely divided abrasives may be used.
suspension and undesirable settling is prevented.
such as pumice, ?nely divided argillaceous ma
The mixture 24 is deposited through the spout
25
terials and the like. I However, I prefer to use
20 onto the grained surface of the metal sheet
?nely divided silica of a ?neness su?lcient to
it’ which is continuously advanced under a doctor
pass a 250 mesh screen. It is the combination
blade 30 serving evenly to distribute the mix
of the alkali earth metal oxide with silica and
ture over the entire surface of the sheet. The
water which appears to produce the desired coat 30 thus covered sheet is then passed over the table
ing or deposit. Under certain conditions, a wa
It and under a plurality of oppositely rotating
ter-soluble blue dye may be incorporated with
brushes 32 which serve to scrub the surfaces of
the treating mixture in order to impart a desir
the sheet in the presence of the mixture of lime,
able whiteness to the coating on the resulting
silica, and water, and to thoroughly contact the
plate. Only traces of the blue dye may be used, 35 mixture with the grained surface of the sheet.
a suitable one being a water-soluble dye known
The sheet I2 is then advanced under a squeegee
as benzoyl blue.
it in order to remove excess quantities of the
For a more ‘complete understanding of this in
mixture, and then is advanced under a plurality
vention, reference will now be had to the draw
of washing brushes 36 which also rotate in op
ing, wherein Figure 1 is a diagrammatic eleva 40 posite directions and serve to remove all traces
tional view of an apparatus which may be used
of excess quantities of silica and lime from the
for a continuous process of producing a litho
_surface of the sheet. Water for the washing
graphic plate in accordance with one embodi
brushes 36 is sprayed on the brushes through a
ment of this invention.
plurality of pipes 38 positioned thereabove. The
Fig. 2 is a greatly enlarged partial sectional 45 corrosion-resistant table Iii serves as a backing
view of a lithographic plate prepared in accord
for the scrubbing brushes 32 and the washing
ance with one embodiment of this invention, hav
brushes 36.
ing the coating or deposit of ink-receptive ma
The strip l2, after having been washed, is then
terial thereon.
passed under a cloth-covered wiping roll 39 and
Fig. 3 is similar to Fig. 2. but shows a prod 50 between the drawing rolls l6, which latter serve
uct having a backing of waterproofed paper ad
to pull the sheet l2 across the table It, and which
hesively secured to the sheet.
.
Referring now more particularly to Fig. l, a
also serve to squeeze excess quantities of water
from the sheet l2, in case such sheet has a pa
roll ill of thin sheet metal is provided which
per backing, as indicated in Fig. 3. The sheet
is capable of being unrolled to advance a con 65 I2 is then advanced through a drying chamber
tinuous strip of metal l2 over a table M of Monel
to, which is equipped with a plurality of drying
metal, glass, or other corrosion-resistant ma
lights 42 positioned above and below the sheets.
terial, by means of drawing rolls I 6. The sheet
The product here may be re-rolled if desired and
l2 may be a thin metal sheet of aluminum or
may be subsequently marked, out and packaged
zinc or other lithographic metal having a thick
60 as needed. However, as shown in the drawing,
ness of about iliooo inch. Such a sheet is ?exi
it is fed directly from the drying chamber 40 into
ble and is, when treated, capable of being in
serted into the carriage of an ordinary type
a printing mechanism M, which prints, with wa- -
ter color ink, markings to serve as guide marks
on the resulting product, and thereafter it is fed
lithographic machine. If desired, the metal sheet 65 into a scoring device 46, and to the cutters it,
l2 may be provided with a paper backing It, as
which serve to cut the sheet to the desired
indicated in Fig. 3. In such case, the metal sheet
lengths. The separate sheets may then be
may have a thickness of about @5000 inch, and
stacked and packaged in any desired manner.
the backing a thickness of about $5000 inch. The
It will, of course, be recognized that both sur
backing is preferably waterproof paper, and ad 70 faces of the strip I2 may be treated in accord
hered to the metal sheet l2 by means of a water~
ance with this invention. It is, in such a case,
proof adhesive. It will be understood. of course,
necessary to subject both sides to a prior wire
that the metal sheet or the metal sheet and pa
brushingbr graining operation before treating
per backing may be of any desired thickness and
the product as herein disclosed. This double
I do not wish to limit myself to the particular 75 treatment may be applied to both sides of a
writer and positioned on the drum of an ordinary
3
2,311,047
the surface of the lithographic plate. This coat
ing is indicated at 50 in Figs. 2 and 3. I do not
metal sheet or to the exposed surfaces of two
metal sheets adhered to each side of a water
proofed paper backing by a waterproof adhe
understand what the true nature of this coating
is, nor do I understand the nature of any physical
or chemical reactions that may be involved in
It has been discovered that a lithographic
its formation. However, I do know that the use
plate prepared in accordance with the process
of the mixture indicated results in an improved
indicated above has many desirable properties
lithographic plate which is much more receptive
which make it superior to lithographic plates
to grease images than are plates which have
which have heretofore been used in the art. It
is very receptive to grease, and is consequently 10 been prepared and cleaned with ordinary abra
sives or chemical cleaning agents.
very useful for accurately reproducing grease
The plate of this invention is extremely ?ne
markings which may be impressed thereupon.
grained and is capable of transferring an ex
After desired markings have been impressed on
tremely accurate image. Markings of lead pen
the plate, either mechanically ‘by a typewriter or
other drawing instrument or by a photolitho 15 cil, crayon and grease ink on the plate are
accurately reproducible and are readily distin
graphic operation, the surfare of the plate may
sive.
'
be wiped with a sponge containing a solution
which is known in the lithographic art as an
guishable one from the others on the surface
composition :
of trichlorethylene and acetic acid. The erasures
are indistinguishable in the reproduction and
fresh markings may be applied to the plate over
printed with the plate of this invention. The
markings on the plate can be erased in case
etch solution whereby those portions of the
surface not containing the greasy material or 20 corrections are desired while the markings are
being applied thereto. Erasures may be made
photographic image are rendered ink-repellent.
by a stiff glass fiber brush or by means of a suit
A particularly useful etch solution prepared in
able solvent, such as a mixture of equal parts
accordance with this invention has the following
Distilled water ________________ __ounces__ 32.0
Glycerine (Y, D.) _______________ __do-___
4.4
the erasures.
Mono-ammomum phosphate______grams-_ 28.8
While particular embodiments of this inven
tion are shown above, it will be understood, of
Phosphoric acid ______ __Sufiicient to adjust the
course, that the invention is not to be limited
solution to about pH 3.8 30 thereto, since many modi?cations may be made,
and it is contemplated, therefore, by the append
This etch has properties which make it, superior
ed claims, to cover any such modi?cations as
to other etches of which I am aware.
fall within the true spirit and scope of this
After the plate has been treated with the etch
invention.
solution, it may be mounted on the drum of a
I claim:
lithograph machine and a grease ink may be
Ammonium sulfate ______________ __do____
2.0
1. A process of preparing a lithographic plate
applied to the surface of the plate by means
which comprises imparting a grain to one sur
of a roll. The ink will adhere only to those
face of a metal sheet, treating said surface with a
portions to which the grease ?lm or markings
have been applied and the grease ink on these 40 mixture of an alkali earth metal oxide, silica
markings may then be transferred directly to
and water, washing said mixture therefrom, and
drying the resulting product, whereby said sur
the surface to be printed or to a cylinder hav
face has been rendered strongly receptive to im
ing a rubber blanket which in turn transfers
pressed greasy markings.
it to the surface to be printed. A fountain etch
2. A process of preparing a lithographic plate
may be applied to the plate by means of a water 45
which comprises imparting a grain to one sur
roll on the lithograph machine in order to in
face of said plate, Scrubbing said surface in the
sure that the ink-repellent portions of the plate
will retain their ink-repelling properties.
In
presence of a mixture of lime, ?nely divided silica
‘and water, washing said mixture from said sur
accordance with one embodiment of this inven
tion, a suitable fountain etch is one which may 50 face, and drying the plate, whereby said sur
face has been rendered strongly receptive to
impressed greasy markings.
be prepared by adding an equal quantity of
glycerine (Y. D.) to the etch composition given
above,
Plates prepared in accordance with this inven
tion retain their accuracy of reproduction over
long periods of time and may be used inde?nitely.
They are also very resistant to oxidation and the
plates may be stored for long periods of time
and re-used. This non-oxidizing coating im
parted to the surface of the metal in accordance
with this invention may be applied to other
metal articles such as they be employed in struc
tural work but, of course, it ?nds particular
use in the preparation of lithographic plates as
herein described.
An important feature of the present inven
tion is the provision of a lithographic plate
which has been treated with a mixture of water,
an alkali earth metal oxide and silica. Any
desired proportions may be used but I have dis
covered that best results are obtainable when
about equal parts of the oxide and silica are
used in admixture with a somewhat greater
amount of water. This mixture when applied as
indicated above forms a deposit or coating on
3. A process of treating the surface of a metal
plate to render it strongly receptive to impressed
55 greasy markings comprising imparting a grain to
said surface, brushing said surface in the pres
ence of a mixture of lime, ?nely divided silica
and water, then washing said mixture from said
plate, and drying the same.
_
.
4. A process of treating the surface of a metal
60 plate to render it strongly receptive to impressed
greasy markings comprising the steps of wire
brushing said surface to impart a grain thereto,
depositing a mixture of lime, silica and water
on said surface, brushing said surface in the pres
ence of said mixture with a plurality of oppo
sitely rotating brushes, washing and brushing
salidt mixture from said surface, and drying the
p a e.
70
5. A process of treating the surface of a metal
strip to render it strongly receptive to impressed
greasy markings comprising imparting a grain to
said surface, continuously advancing said strip,
depositing a mixture of lime, silica and water on
75 said surface, brushing said surface in the pres
Mia.
%,811,0%7
ence of said mixture as the strip continuously is
advanced, then washing said mixture from said
surface, drying the same, and cutting the strip
into predetermined lengths.
mixture of an alkali earth metal oxide, a ?nely
divided abrasive and water, washing said mix
ture therefrom, and drying the resulting prod
uct, whereby said surface has been rendered
6. The process of claim 5 in which said strip ta strongly receptive to impressed greasy markings.
is‘ continuously marked and scored prior to cut
10. A lithographic plate comprising a thin ?ex
ting.
ible metal sheet having the normal lithographic
~ '7. An etch solution for treating the surfaces of
surface thereof grained and treated with a mix
lithographic plates comprising water, glycerine,
ture of an alkaline earth metal oxide, a ?nely ‘
mono-ammonium phosphate, ammonium sulfate 10 divided abrasive, and water to provide a grease
and phosphoric acid.
receptive coating thereon.
8. A process of preparing a lithographic plate
11. The lithographic plate recited in claim 10
which comprises treating the surface of said'plate
wherein said abrasive comprises silica.
with a mixture of an alkaline earth metal oxide,
12. The lithographic plate recited in claim 10
?nely divided silica and water whereby a grease 15 wherein said alkaline earth metal oxide com
receptive coating is formed thereon, applying de
sired grease markings to said surface, and treat
prises lime.
13. The lithographic plate recited in claim 10
wherein said sheet comprises aluminum.
14. The lithographic plate recited in claim 10
ing said surface with an etch to render grease
repellent those portions of the surface not cov
ered with the markings, said etch comprising an 20 wherein a sheet of waterproofed paper backing
aqueous solution of glycerine, mono-ammonium
is adhesively secured to the opposite surface of
phosphate, ammonium sulfate, and phosphoric
said metal sheet.
acid, whereby to form a ?ne-grained plate ca
15. A lithographic plate comprising a thin ?ex
pab'e of transferring an extremely accurate im
ible aluminum sheet having the normal litho
age of said grease markings.
graphic surface thereof grained and abraded with
9. A process of preparing a lithographic plate
a mixture of lime, ?nely divided silica, and water
which comprises imparting a grain to one surface
to provide a grease-receptive coating thereon.
of a metal sheet, treating said surface with a
WILLIAM T. HAGELIN.