Improvements in Photographic Printing.
Year: 1897

page_text: Date of Application, 27th July, 1897-Accepted, 12th Mar.,
1898
COMPLETE SPECIFICATION.
Improvements in Photographic Printing.
I, ARTHUR SCHWARZ, of Berlin, Schöneberg, Germany, Manager of Works, do
hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
-
When photographic paper, sensitized on both sides, is being used for making
copies of pictures, it is important that the pictures on one side register as much as
possible with those on the other side, unless very heavy paper is being used, which
would, however, imply the partial loss of the advantage of using paper sensitized
on both sides.
I have devised a copying frame or machine measuring the exact registering of
the pictures, and in which the sensitized paper is exposed simultaneously at the
same spot on both sides.
I have illustrated the new copying or exposure apparatus in the annexed draw-
ings, making a part of this specification, and wherein:-
Figs. 1 and are sectional views of flat copying frames, Figs. 2 shows a flat
copying machine. Figs. 3.and 4 are sectional views of a round copying frame.
The exposure apparatus shown in Figs. 1 and 1^ presents two superposed flat
copying frames A and A' in which the glass plates and a¹ are supported, and
hinged together in any suitable manner. One series of negatives 6 is attached to
the plate a and a second series b¹ to the plate a¹.
The paper c sensitized on both sides is placed between the flexible nega-
tives b and b¹, care being taken of course that the two glass plates a and a¹ be
arranged exactly parallel to each other in the frames A and A¹. The combined
thicknesses of the negatives band 61 and of the sensitized paper c must be of
a sufficient size, so that when the frames A A¹ are pressed together by clamp or
other suitable devices, the negatives will be closely and firmly pressed against the
sensitized paper.
If the negatives 66¹ and the sensitized paner c do not present the required thick-
ness to obtain the necessary pressure when the frames are clamped together, a
transparent or translucent plate z of celluloid or other suitable material may be
placed under one or both of the glass plates so as to obtain the necessary pressure
(Fig. 2).
In this case, the negatives must of course be attached to the transparent plates z
and not to the glass plates, so as to prevent unclearness in the copies.
If air pressure is employed to force the negatives against the sensitized paper as
usual in the pneumatic copying apparatus, the second glass plate a¹ is eliminated
and is displaced by a celluloid plate z as shown in Figs. 1 and 2.
This apparatus is a continuous operating one, and is used for the wholesale pro-
duction of copies.
The frame A carrying the glass plate a is fixed upon the table board B and is
equipped at its edges with closing rims d. A similar frame A¹ with closing
rims d and provided with a celluloid plate z instead of the glass plate is movably
arranged under the frame A so that it can be raised or lowered at will.

page_text: To this end the frame A¹ is connected to the rod E, provided with lateral guiding
pins e passed through eyes f connected to the supports B'. Springs F are mounted
on these guiding pins e between the rings and the frame A¹.
Now, when the frame A¹ is lowered together with the rod E and the slide G pro-
vided with stud y co-operating with the driving shaft b and the crank disc H
mounted thereon, the sensitized naner c can be fed in the double frames A A¹
between the negatives b b¹.
If the crank disc H has rotated far enough to release the stud g the spring F will
push the frame A¹ upward and the rims d d¹ will form with the sensitized paper c
an airtight enclosure.
At this moment the driving shaft h has caused, through a suitable gear, the
crank disc to turn so far as to release a spring actuated lever i sliding on the
circumference of its segment, whereby a cock m is opened, arranged in the suction
pipe K communicating with a continuously operating air pump or a vacuum tank.
The air in the space between the sensitized paper and the flexible plate is
exhausted at once, and the atmospheric pressure pushes this plate with the negatives
attached thereto against the sensitized paper c and said paper. against the flexible
negatives attached to the glass plate.
Now, if the light is admitted above and below through the transparent plates,
by means of suitably arranged electric lamps the paper is exposed on both sides,
and as the arrangement enables the operator, before the sensitized paper is fed
correctly to ascertain the position of the upper and lower negatives and whether
they register, it is absolutely sure that after the exposure the copies of the pictures
on both sides of the paper will register.
The
Figs. 3 and 4 show the manner in which the lighting is effected on both sides
by the aid of a rotating duplex machine. The frame is shrunk on a transparent
cylinder M upon which the negative is fixed and which turns on the shaft m.
Upon the cylinder M is placed an endless and entirely or partly transparent
blanket N in such a manner as to pass over the cylinder over guide rollers n' n² and
back to the same cylinder being tightly pressed by a tension roller X upon the
cylinder M so as to adhere to the negative. Upon the blanket N to which the
second frame A' with the plate z is connected the negatives 61 are so fixed as to
accurately coincide or register with the negatives 61 when the cylinder M turns
and carries away with it the blanket N as clearly shown in Figs. 3 and 4.
sensitized paper is introduced between the negatives b fixed to the blanket N and
the negatives b fixed to the glass cylinder M in such a manner that the points of
insertion and of withdrawal are close, one to the other, and hence the periphery
of the cylinder M is used up as far as possible. Between the part of the trans-
parent blanket N which surrounds the cylinder M and the part which runs over
the guide rollers n'n' there is left an open space which is conveniently used as a
lighting chamber by placing therein electric lamp trays are arranged in this
open space to which the electric lamps o are fixed, these trays are connected out-
side .e. by the side of the copying device, with a fixed rod, bar, frame or the like
(omitted in the drawings for the sake of clearness) as well as with an electric
circuit in order to illuminate from the outside through the blanket N the sensi-
tized paper surrounding the cylinder M. To light up the other side of the sensi-
tized paper e opposite the cylinder M, electric lamps ō are arranged inside the said
cylinder M which are supplied with electricity from a suitable circuit.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:
1. A copying frame, both sides of which are transparent or translucent for the
exposure, of photographic paper sensitized on both sides, substantially as described.
2. In a pneumatic copying frame the arrangement of a rigid transparent or
translucent plate at one side and of a flexible transparent plate at the other side,
substantially as described.

page_text: 3. In a pneumatic conving frame of the class described the combination of a
rigid upper frame, with a movable lower frame, means for moving same up or
down, and means for exhausting the air when the two frames are pressed together
substantially as described.
4. In pneumatic copying frame of the kind described the use of a rotating light-
ing apparatus wherein a transparent or translucid rotating endless blanket is
travelling around a transparent or translucid cylinder and is provided with the
flexible negatives which are illuminated through the said blankets, substantially
as herein described and shown.
DE KATOW & Co.,
Agents for the Applicant.