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Патент USA US2137725

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Nov. 2z, 193s;
R, R I_Ewlg
Filed NOV. 27, 1954
1ra/ees» myn?
Patented Nov. 22, 1938
Robert n; Lewis, Baldwin, N. Y.. -assignor to vul
- can Proofing Company, -New York, N. Y.; a eor- _
poration? of New York
'Application November 27, 1934, Serial No. 754,993
y.z claims.
LMy invention relates to a new and improved
transfer device, to be used vfor the photomechan
ical reproduction ofy printing plates.
One ofthe objects ofmy invention- is to pro
` 5 vide a device which can `be used in 'connection with
the method of making printing plates which is
disclosed in U. S. Patent No. >1,382,613 issued on
(Cl. 411-46)
which’is coated with athin layer of substantially
yReferring to the annexed diagrammatic draw
ing, the inner surface of the transparent or trans-f
lucent sheet 3, which is made of cellulose acetate,
is especially prepared in order to enable the rubber
coating 2 to adhere thereto. Said inner surface
June 28, 1921,-and ,in Canadian Patent No. 325,250l 4 of the sheet 3 may be so prepared, so as to give
~it a sufficiently rough surface, by means of em
issued, on August _23, 1932.
Another object of my invention is to provide bossing, or by any other process.« Likewise, said
an improved device for mechanically producing a inner surface of the sheet 3 couldbe roughened by
photographictnegative‘ from a photo-engraving.> coating the same with a mixture containing crys
' Another object of my invention is to provide
a .device having a tacky material, and which can
>be'conveniently manufactured and shipped and
handled, said transfer device having means for
protecting said tacky material until the device is
to be used.
talline substances.
Such a mixture could consist
of gelatine having mineral crystals. The sheet
3 remains light-permeable and substantially 16
transparent or translucent, after it has been pro
vided with' a rough inner surface.
The roughenedsurface which is thus secured,4
is provided with a'coating or-layer 2. This coat--
Other objects of my invention will be set
. ing or layer 2 consists substantially of pure rubber. 20
À2o. forth in the following description and drawing.
It may consist of 95 _parts of the whitest obtain-l
able grade «of first latex crepe, and 5 parts of
ft has heretofore been well known to make a
white petrolatum. -T’his rubber mixture: is milled
to give it satisfactory calendering -qualities and
Fig. 1 is a diagrammatic cross section of
improved device.
Fig. 2 is a diagrammatic plan view.
25 printing plate from a relief plate'of the subject.
rli‘his relief plate may be made of metal, and it
may be etched. Accordingfto this well-known
method, as disclosed in the above mentioned
'United States patent and the Cabove- mentioned
Canadian patent, the plate is first cleaned, and
this mixture of rubber and petrolatum is then 25
applied to the base i, by means of a calender.
The thickness of the coating 2 can be from two
thousandths of an inch to three thousandths of an
It will be noted that I do not use av coating or so
layer which is a solvent for the cellulose acetate,
then a suitable opaque pigment is applied to the
printing surface of the plate, >so that the pigment - and thatl use a tacky rubber layer which is` ap
plied in iinal form to the base sheet 3. I do not
Vfiller fills up the etched or relief portions of the
- plate, to a level with the printing surface of
-35 said plate.
' This plate, so prepared, is then pressed against
the surface of a suitable base sheet made of
Celluloid or other suitable cellulose material. Ac
- cording to said U. S. Patent No. 1,382,613 the sur
40 face of the base sheet of Celluloid is coated with
Wish to- be limited to the use of cellulose acetate,
as I can use other suitable opaque or transparent 35
or translucent material. I prefer to use cellulose
»acetate because l have discovered that it holds its
dimensions more accurately than similar material,
during the photographic printing operation.
~ However I could use sheets of cellulose nitrate
-material or any other light permeable material.
an adhesive which is a solvent of Celluloid, just
The coated sheet 3 is now covered with a third
before' the transfer is made.
According to said Canadian patent, a sheet of
g paper or tracing cloth of Celluloid or “Cellopha‘ne”
or 'covering sheet l, which is also preferably made
of cellulose acetate. The covering sheet l is
preferably provided with a smooth inner surface, 45
or gelatin, is coated with a thin layer of rubber in
solution, in order to form an adhesive film on the
transparent or translucent sheet, just before the
transfer is made, and the rubber solution is used
and it is applied to the coating 2 of Ásheet 3, im
mediately as the coated sheet 3 comes from the
I 50 for removing the pigment from the metal relief
of material'which are thus secured, are then >cut
printing plate.
According to my. invention, the metal relief
plate, prepared, in the >manner previously de
scribed, or in any other manner, is used for print
55 ing a'negative- upon a sheet of cellulose acetate,
The rubber is not vulcanized. The large-sheetsto various sizes and packaged for shipment.
can use any suitable smooth or other material for
the covering sheet I.
When the device is to be used, the covering
sheet is removed and the tacky layer of rubber . '
remains adherlngto the base sheet l, because
said base material has a rough surface, and the
covering material has a smooth surface. Hence
the adhesion of the layer 2 to sheet 3, exceeds its
sheet would substantially prevent any evapora
tion of the solvent, and the transfer device, to
gether with its covering sheet, could be packed in
adhesion to sheet i. T'his eifect or result can be
secured in any suitable manner. Since the layer
2 is very thin and coherent, it remains adhering
substantial evaporation of the solvent. However,
to the rough surface of the base sheet. This base
sheet I, together with its tacky layer, is used in
10 the same manner as thev base sheets which are
disclosed in the patents previously mentioned.
That is, when a metal relief plate which has been
coated with a printing composition in its recesses
is pressed against the rubber layer, a reproduc
15 tion- of the plate is formed upon the tacky
layer 2.
mula of the rubber layer, without making it un
suitable. 'I'he essential characteristics of the rub
ber layer are that it shall have a surface of suf
iicient tackiness to pull .the particles of pigment
from the metal relief plate, and that it shall be
as colorless as possible, and as transparent as
possible. Likewise, the tacky material should re
main unchanged, during moderate periods of
storage under average conditions.
The base sheet 3 and the protective sheet I,
have a thickness of .0075 inch. This thickness
can be varied without departing from the inven
any suitable wrapper, whichx could prevent any 5
and for the reasons previously described, I prefer
to use a dry tacky layer.
I have described a preferred embodiment of my \
invention, but it is clear that numerous changes 10
and omissions could be made without departing
from its spirit.
The thin sheet of cellulose acetate material,
used for making the base sheet or the -covering
sheet, is bendable and resilient, so that each said 15
sheet has a predetermined normal shape.
'I'here can be considerable variation in the for
If such a layer were used, the covering
For convenience, the device may be designated
as a “transfer” device, since a replica of the metal
plate is transferred to the tacky layer, by means
of pressure. Likewise, the tacky layer may be
35 designated as a dry tacky layer, since the tacki
ness does not depend upon the addition or use of
any solvent. The petrolatum may be omitted or
it may be substituted by any other suitable ma
terial which can increase the calenderlng proper
40 ties of the rubber. Likewise, I do not wish to ex
clude from the scope ofv the invention a tacky
rubber layer, which has solvent intermixed there
I claim:
1. A transfer device for use in photo-mechani
cal printing, said device comprising a base sheet
made of light-permeable material and having a
smooth outer face, said base having a light
permeable layer of tacky material at the inner
face thereof, and a covering sheet which substan
tially covers said layer, of tacky material, said
base sheet having a roughened surface directly
adjacent said layer of tacky material, said layer
having greater' adherence to the base sheet than
to the covering sheet, so that said layer adheres
to said base sheet -When the covering sheet is
2. A transparent transfer device comprising a
base sheet made of transparent and resilient ma
terial, said base sheet having a roughened face,
a layer of tacky material on said roug'hened
face, said tacky material consisting substantially 85
of unvulcanized transparent latex crepe, and a
cover sheet applied to said layer of tacky mate
rial, said base sheet having sufficient adherence to
said layer to retain the same, when the cover
sheet'is removed.
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