Improvements in Photographic Printing Apparatus.
Year: 1897

page_text: Date of Application, 27th July, 1897-Accepted, 22nd Jan., 1898.
COMPLETE SPECIFICATION,
Improvements in Photographic Printing Apparatus.
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:
In the apparatus used for illuminating sensitized paper for the purpose of printing
off photographic copies, the negatives are firmly pressed, by the aid of a blanket,
against the sensitized paper. When the paper has been sufficiently illuminated,
fresh sensitized paper is inserted under the negatives for which purpose the blanket
must be removed.
When only a limited number of copies is required the ordinary apparatus are
sufficient but when a large number of copies are wanted such apparatus ceases to
answer the purpose, as the removal and replacing of the blanket entails too great a
loss of time.
The
These defects are remedied, according to this invention by using a rotary blanket
such as illustrated by way of example in the accompanying drawings.
transparent negatives are fixed in any suitable manner upon a transparent or
translucent cylinder A turning upon the shaft ; over this cylinder passes the
suitably guided sensitized paper which enters at X and leaves off at Y. Guiding
rollers c c c² c³ are distributed around the cylinder A (preferably in a detachable
frame C), endless blanket D being passed around the same in such a manner as to
surround the cylinder. This blanket firmly presses the sensitized paper D against
the negative a on the cylinder A, such pressure being produced by the aid of the
pressure roller E arranged between the two guide rollers c³ ct. This pressure roller
is arranged to slide relatively to the cylinder A, so that by bringing such roller in
close proximity to the cylinder, the pressure of the blanket on the paper can be
regulated according as required; as the cylinder A turns it carries away with it the
sensitized paper B and the blanket which are firmly pressed against the same, but
while fresh paper is led to and removed from the cylinder the blanket turns constantly
over the rollers c c and the cylinder A. The speed of the cylinder A is so calculated
that while the sensitized paper ascends upon and descends from the cylinder, the
image is properly developed.
To affix fresh negatives to the cylinder, the frame C is opened so that the blanket
may assume the position shown in dotted lines and the negatives are placed upon the
cylinder A while the same rotates. In the arrangement shown, the cylinder is
transparent and the source of light such as one or more electric lamps is placed inside
the the same.
This however is not indispensable, as an opaque cylinder may also be
used, provided the blanket is made of transparent or translucent material in which
case the negatives are affixed to the blanket turning herewith upon the cylinder A
and the rollers c¹ to c successively beat, as soon as they turn on the cylinder, upon
the sensitized paper, while maintaining their position relatively to this paper, until
the blanket runs off the cylinder and rotates over the rollers c to c and off. In
this second arrangement the light from outside falls through the blanket D and the

page_text: negative b upon the paper, while in the first arrangement the light emitted inside
reaches the sensitized paper through the cylinder A and the negatives b.
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. In photographic copying apparatus, an illuminating device for printing off
copies upon sensitized paper by means of rotating blanket, substantially as herein
described and shown.
2. In the illuminating device above claimed, a transparent or translucent blanket,
substantially as herein described and shown.