Improvements in Duplex Printing Machines.
Year: 1899

page_text: Date of Application, 9th Mar., 1899-Accepted, 13th May, 1899
COMPLETE SPECIFICATION.
Improvements in Duplex Printing Machines.
I, HUGO KOCH, of Leipzig-Connewitz, Germany, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be par-
ticularly described and ascertained in and by the following statement:
-
Various attempts have been made to construct improved printing machines
for metal lithographic-plate printing since such prepared metal plates were first
employed as a substitute for lithographic stones with the object of avoiding the
losses of time caused by ordinary surface printing machines.
as
The novel printing machines heretofore constructed to this end resemble more
or less the well known rotary typographic machines having continuously rotating
cylinders whose circumferential velocities are capable of being increased
desired. Now as individual sheets and not roll-paper are employed with litho-
graphic printing machines, which sheets of paper must be laid very accurately
and this particularly in lithochromic printing, the advantage of the high
velocity imparted to the printing rollers is rendered illusive; indeed, for pro-
ducing neat prints or impressions, there must be time enough for carefully and
accurately laying on the sheets to be printed, otherwise the produce of rotary
presses would only be increased at the sacrifice of the impressions.
My present invention avoids these objections, increases the produce of litho-
graphic printing machines, and improves the quality of the impressions; it re-
lates to a novel construction of duplex lithographic printing machines, the object
being to provide a machine of this kind, in which two impression rollers are
employed arranged on the sides of a rocking plate-roller, to which motion is
imparted by a toothed sector connected with a spur-wheel by means of a con-
necting-rod, said spur-wheel imparting a rocking motion to said sector. Said
impression-rollers are alternately thrown into gear with the plate-roller through
the agency of suitable gear-wheels, so that whilst one impression roller is moved
into contact with the printing-plate, the second impression-roller will be stopped
to leave sufficient time for laying on the sheet.
In order that my invention may be properly understood I have hereunto
appended one explanatory sheet of drawings whereon:-
Fig. 1 is a diagrammatic elevation of the improved printing machine.
Figs. 2 and 3 are detail views showing different positions of the plate and im-
pression rollers.
Fig. 4 is a detail view showing the parts for transmitting motion to the im-
pression-rollers.
On the drawings the same reference letters indicate the same parts through-out
all the figures.
The continuously rotating spur-wheel a, provided with a crank-pin, is con-
nected with the toothed sector c by means of a connecting-rod b, said sector being
mounted on a shaft journalled in the frame of the machine. The spur-wheel
mounted on a shaft a¹, may be actuated by a motor in any desired and suitable
manner, through the agency of a train of gear-wheels f¹, i, as shown in Fig. 1.
It will be readily seen that said 1otating spur-wheel a will impart a rocking
movement to said toothed sector c. The teeth of the latter mesh with a toothed

page_text: wheel secured on the plate-roller and impart a rocking motion to the same
The connection between toothed sector e and pláte-roller is such that one oscil-
lation of the former will cause the latter to perform a complete révolution to the
right or the left according to the direction of said oscillation.
On each side of the plate-roller d is journalled an impression-roller e or f,
said impression-rollers carrying suitable gear-wheels adapted to mesh with the
gear-wheels on said plate-roller. Said impression-rollers & and fare provided
with catchers and receive the sheets to be impressed.,
The gear-wheels on the impression-rollers e and fare alternately thrown into
gear with the gear-wheel on the plate-roller by means of forked levers and h,
Fulcrumed at g and respectively and actuated by suitable cams through
the agency of bars k, pivotally connected with the lower ends of said forked
levers gand h, so that the printing surfaces of said rollers e and f are alternately
moved into contact with the plate on the roller d, as indicated in Figs. 2 and 3
of the accompanying drawings.
i
... f
As the plate-roller d is rocked to the right, the roller e will be thrown into gear
with, whilst the roller f will, remain motionless during a complete revolution
of said plate-roller d. Similarly the roller e will be motionless whilst the plate.
roller is rocked to the left in order to rotate the roller f.
It will be readily understood that such periodical and alternate stoppages of
the impression-rollers will enable the layer-on to accurately lay on the sheet to
be printed and perfectly register same in the case of lithochromic printing.
The inking devices r, p, the wetters 1, m, and the flyers #, o, indicated in the
drawings (Fig. 1) are constructed and arranged in the usual, way and do not form
part of this invention.
I would have it understood that I do not restrict myself to the minor details
of construction and arrangement of parts herein shown and described, as many
changes may be made therein without departing from the spirit and scope or
sacrificing any of the advantages of the invention.
:
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed I declare that what I
consider novel and desire to claim. is:-
1. In a printing-machine of the class described, the combination with a rocking
plate-roller of two impression-rollers arranged one at each side of said plate-
roller and adapted to be alternately thrown into gear with the latter, and suitable
means for imparting motion to said rocking plate-roller, substantially as set forth.
2. In a printing-machine of the class described, the combination with a rocking
plate-roller, of two impression-rollers arranged one at each side of and adapted
to be alternately thrown into gear with said plate-roller, a toothed rocking
sector meshing witli said plate-roller, and means for alternately throwing said
printing rollers into gear with said plate-roller, substantially as set forth.
.
3. In a printing machine of the class described, the combination with a rocking
plate roller, of two impression rollers arranged at the sides of said plate, roller.
fulcrumed forked levers suitably actuated to alternately throw said 'impression-
rollers into gear with said plate-roller, a toothed rocking sector meshing. with
the plate-roller, a connecting-rod pivotally secured to said sector, and a con-
tinuously rotating gear wheel actuating said connecting rod, substantially as set
forth.
4. The general arrangement and pombination of parts of the mechanism sub-
stantially as hereinbefore described with reference to the drawings annexed.
Dated this 8th day of March 1800
H: D. FITZPATRICK;
100, Wellington Street, Glasgow, Agent.