Improvements in Rotary Printing Presses for Lithographic Printing Plates.
Year: 1895

page_text: Date of Application, 19th Apr., 1895-Accepted, 20th July, 1895
עשר JV
[Communicated from abroad by THE MASCHINENFABRIK JOHANNISBERG
KLEIN, FORST AND BOHN successors, of Geisenheim on Rhine, Germany,
Engineers.]
Improvements in Rotary Printing Presses for Lithographic Printing
Plates.
İ, SAMUEL SIDNEY BROMHEAD of 97 Newgate Street London, Patent Agent,
(a communication,) 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 :-
The rotary press forming the object of this invention is designed to produce
prints from plates of aluminium, zinc or similar metal, which have been secured
upon a cylinder.
Many devices have been designed to attain this result without attaining practical
success for the machines were either unfit to produce a satisfactory result, or the
prints were not sufficient to answer the demands in quality. A machine, answering
practically to the expectations of the trade must fulfil the following conditions:-
(1.) It should produce at least as good work as an ordinary flat bed press.
(2.) It should produce more work than the flat press.
(3.) It should be easy to handle it.
All this is attained by the rotary press described below, and shown in the
accompanying drawings, wherein :-
Figs. 1, 2 and 3 are cross sections through the plate-cylinder and press-roller,
showing the same and the elements feeding and guiding the paper in different.
positions.
Figs. 4, 5 and 6 illustrate diagrammatically the different positions of the
co-operating surfaces of plate-cylinder and press-roller.
Fig. 7 is a side elevation of the press, partly in section.
The sheets of aluminium, zinc and the like, serving as printing plates are secured
upon a cylinder C, the plate-cylinder, which is of such dimensions, that the surface
to be actually covered by the plates is only one third of the whole circumference.
The press-roller B, having as its object, to give the impression upon the sheet of
paper to be printed has a diameter equal to only two-thirds of the diameter of the
plate-cylinder C. Both cylinders are in gear by cog wheels and revolve with equal
circumferential velocity. Consequently the press-roller B makes three revolutions,
while the cylinder C makes two only, and besides the surfaces of the two cylinders
which come into contact, shift at each revolution for one third of the circumference
of roller C as illustrated by Figs. 4, 5 and 6.
The figures show that only one half of the surface of the press-roller is used for
the impression while the other half is set back, also the roller C has only one-third
of its surface adapted to receive the plates while the other two-thirds are set back,
forming the surface of a somewhat smaller cylinder; consequently the impression
between these two rollers can be only made, when their said projecting surfaces are
in rolling contact with each other. This is effected, when the press roller B has
made three revolutions and roller Chas made two. (Figs. 4, 5, 6 and 7.)
For the same reason the printing surface of roller C passes the moistening
:
f

page_text: rollers R R and the inking rollers LL¹ (Fig. 7) twice, before an impression
is effected, so that a double inking in of the plate occurs before each impression,
while in the ordinary machines of this kind only one inking in is effected.
It is obvious that in this respect the new machine offers great advantages.
In order to obtain perfect proofs it is however also necessary, that the sheets,
when repeatedly carried between the rollers for impression have the same position
of point marks, made at the first impression.
This is comparatively easy in machines with rollers having an intermittent
rotary motion, and therefore many constructors set the press roller fast and let it
revolve alternately. It is obvious that the efficiency of the machine is hereby
lessened and to avoid loss in the number of impressions obtainable, the machine
must be so arranged, that the sheets are well registered even at a continuous
revolution of the cylinder. To this end the machine is constructed in the
following way.
The table A (Figs. 1, 2, 3 and 7) is arranged close above press roller B being but
slightly inclined. The paper shifter, of known construction, not shown in the
drawings, pushes the sheet on table A crosswise into the right position. The
ordinary front marks however are insufficient to guide the sheet in the other
direction, and in their place a device is used as shown in Figs. 1, 2, 3 and 7.
The table A is provided at both sides with supports t wherein a shaft a
oscillates.
The marks or points b are adjustably secured on this shaft or bar, capable of
being moved on it lengthwise. The marks 6 have the object to limit the position
of the sheet at its lower edge and simultaneously to carry the sheet at this edge.
To allow more or less of the paper to pass under the grippers i, an arm g is
secured on shaft a and leaús against a set screw farranged in one of the laterial
supports t. By adjusting the screw f, the shaft a, is turned and the marks bare
more or less removed from the table A. The edge of the paper will correspondingly
project more or less over the table and thus more or less paper comes under the
grippers. By the adjustment of the screw, the paper sheet will therefore take
its position on the press roller B' more or less advanced.
It may happen that the front edge of the sheet be more advanced on one side
than on the other, and to readily meet this difficulty I have arranged the marks b
in their holders adjustable by screws h. The same result may be obtained also, by
making the supports & adjustable.
The marks should swing back in order to clear the way for the paper when it
is held by the grippers, therefor fingers c are arranged to come down upon the
paper (Fig. 2) and hold it on the table A while the marks swing back. These
fingers go back in the moment, in which the grippers catch hold of the sheet.
In order to prevent the grippers to strike against the edge of the sheet, which
might displace it, provisions are made that shortly before the grippers approach the
paper, a current of air strikes the edge of the paper, passing through holes u of a
pipe w into which air is pressed, so that said edge of the sheet is pressed down
smoothly upon the surface of the cylinder. For the exact pointing it is necessary
that the grippers on the roller revolving continuously, press upon the sheet always
on the same spot.
To this end the gripper bar is provided with two different mechanisms for
in parting motion. The grippers before seizing the paper, must be so wide open as
to touch neither the table A, nor the paper, and therefor the grippers with the
gripper bar must be turned for about 180°, and must then close quickly.
This quick motion cannot be executed with sufficient accuracy in the manner at
present in use, and in order to obtain a movement of the grippers which is certain
I employ a device, opening the grippers and preparing their back motion, whereupon
a second mechanism forces the grippers to close.
These two mechanisms co-operate in the following manner: The spring p secured
to the lever or arm r of the toothed sector o has the tendency to open the grippers
by means of the teeth of said sector and pinion k.

page_text: The roller of arm 7 in passing over the cam surface s, effects this (Fig. 1) and
the grippers pass wide open under the table A.
When the roller of arm r, arrives upon the cam s', the grippers i, close as the
arm is lifted by s¹. The lever m being secured on 1 swings thereby forward, and
its roller m comes in contact with the cam surface n thus closing the grippers i
quickly and with certainty.
The method of working the machine is the following
--
The sheet of paper is placed on the table A against the previously adjusted
marks b (Fig. 1).
Shortly before the grippers of the press roller B close and take hold of the
paper, the fingers o descend upon it and the marks b recede. From the pipe w.air is
now blowing upon the edge of the paper, pressing it against the cylinder B (Fig. 2).
The grippers i, moved by the cams, arm sector o, pinion k, lever m and camn,
close and seize the paper, in the same moment the fingers ego up, and the grippers i,
carry the paper forward with the press roller B (Fig. 3).
After the impression the grippers deliver the paper upon the discharge drum D,
the grippers d of which seize the sheet (Fig. 1) and carry it, as soon as the
grippers i on roller B open to release it, for a part of its circumference upon said
drum D till it arrives upon a system of ribbons F, by means of which it is brought
upon the rake T which turns the paper over, and deposits the sheets, printed face
upwards, upon the table E (Fig. 7).
When the grippers i, open, to abandon the printed sheets to the drum D, the
eccentric with the cam surfaces n, s, s, is shifted sideways in such a manner, that
the grippers i, while roller of arm passes behind s¹, remain fully open during
the following two revolutions of press-roller B, they rest with their points against the
edge of press-roller B.
When the press-roller B at the next revolution comes into the position indicated
by Fig. 1, the eccentric with the cam surfaces n, s, s', moves in again, the roller r
of arm r, runs upon the cams and the grippers i, closing, take hold of a fresh sheet
of paper and a new impression is effected in the above described manner.
During the three revolutions of cylinder B the roller C has only made two, and
its surface covered with the plate of aluminium or zinc has twice passed in front of
the moistening rollers R, R', which are covered with rubber, and any suitable
fabric capable of holding water.
The rollers R, R¹, take up moisture from a roller having the same circum-
ferential velocity as roller C. The water is carried up from the trough M by
means of intermediate rollers N, O, P, as shown in Fig. 7.
As stated above, the cylinder C passes for each impression with the plate twice
before the rollers R R and also twice before the inking rollers L, L'. These
latter are arranged on the side of the plate-cylinder, in order to give easy access to
the same; they take the ink from a roller J having the same circumferential
velocity as cylinder C. The conductor G transfers the ink from the well by means
of roller H in the ordinary way upon the roller J, and the small rollers K are
provided for the purpose of smoothing out the ink on said roller J, so that it passes
from the same in a uniform manner upon the ink rollers. L, L', and upon the
printing plate. The part of the cylinder C not carrying the printing plate, is set
back and therefore cannot take any ink or water.
As already stated, the printing cylinder and platen cylinder are in the proportion
of two to three, that is to say the printing cylinder B is two-thirds of the size of
the platen cylinder C. This proportion has been chosen in order to render it
possible that in oue impression the platens of the cylinder Care twice moistened
and inked, this double inking being necessary for obtaining a clear and sharp
impression.
From Figs. 4, 5 and 6 it will be seen that the printing surfaces of the cylinders C
and B change their relative positions in every revolution of the cylinder B.
In Fig. 4 the printing surfaces of B and C are opposite each other, so that an
impression takes place in the further rotation.

page_text: After the completion of the first revolution of the oylinder B, the platen
cylinder C. has only made two-thirds of a revolution (Fig. 5). Opposite the
printing surface of the cylinder B, is in the further movement, a blank portion of
the periphery of C, while the platen surface of C will be opposite to the blank
portion of the periphery of the printing cylinder B. After the completion of the
second revolution the cylinders are as shown in Fig. 6.
In the following third revolution of B, the entire periphery of the same is
developed upon the blank peripheral surface of the cylinder C, and the two
cylinders, on the termination of the third revolution pass again to the position
indicated in Fig. 4, wherein a fresh impression will commence.
Accordingly by the proportion of the cylinders of 2 to 3 it is rendered possible
that only after every third revolution of the printing cylinder B, the two printing
surfaces come into contact, so that only then an impression will take place.
It will be seen that as the printing surface of the cylinder B, corresponds in the
turning movement several times with the blank surface not surrounded by the
metallic plate, of the cylinder C, and vice versa the platen surface of the cylinder C
with the peripheral surface, not serving as a printing surface, of B, it is necessary
to cause these unused blank surfaces of the platen and printing surfaces proper to
spring back, so that in the revolutions neither the printing surface nor the platen
surface come in contact with the surfaces not used and are not thereby injured.
If the unused surfaces did not spring back, it would not be possible to cause the
printing of the metallic plates to be twice inked, because the printing cylinder B
would take off with its unused surface the ink put on, and the unused surface of C,
if not sprung back, would likewise be moistened and inked, whereby, as the printing
surface of B would come in contact with the unused surface of C, the cover of
the cylinder B and consequently the back of the sheet to be printed would become
dirty.
Figs. 8 and 9 show the laying apparatus and the double catch mechanism carried
out on a large scale, in order to enable the mode of motion of the two mechanisins
to be showu.
Upon the shaft a, on which the marks are laterally adjustable, is loosely
arranged a lever 3 to which a rod 6 is attached. This rod 6 receives upward and
downward movements through the intervention of the double lever 13 and rod 14,
by means of an eccentric placed on any desired shaft of the machine, but this shaft
must have half the number of revolutions of the cylinder C, that is to say
when C makes two revolutions the shaft will make only one revolution.
On the lever 3 is arranged a screw 23 which strikes against a tappet 24 of the
arm g fixed upon the shaft a. The arm g, and with it the shaft a and marks b, are
held by a spring 25 attached to the lever 1 in a position limited by the adjusting
screw f
A small projection 9 on the rod 6 draws down a lever 8, which is arranged upon
the, shaft 26, carrying the curved fingers c.
When a shect is placed against the marks b, the rod 6 is in its highest position,
the spring 25 has drawn the shaft a with the marks b and the arm g against the
adjusting screw, the projection 9, by the lever 8 has raised the finger c, in like
manner the lever 10 and roller 11 are in a raised position. The tube wis turned
by the lever 4, through the medium of the rod 5 by the arm g so that the holes.v
are closed.
If the catches begin to close the rod 6 is lowered, the lever 8 as the rod 6
descends moves downwards, and the fingers c bear upon the sheet laid on; now the
screw 23 strikes against the catch 24, and turns the arm g with the shaft a and the
marks backwards, at the same time the tube w is turned by the lever 4, so far,
that the holes v coincide, the current of air passing out forces the sheet upon the
edge of the cylinder B. At the same moment when the catches are closed, the
roller 11 of the lever 10, passes on to the curved path 12, and is raised a little by
the latter, the finger c following this movement, and allowing the passage of the
sheet seized by the catches i.

page_text: are
When the sheet has passed through, the rod 6 is raised, the fingers
completely raised by the projection 9, the shaft a with the marks b, pulled by the
spring 25, swings forwards and the arm gbears against the adjusting screw!f.
A fresh sheet may now he put on.
The double lever 13 has its pivot on an arm 37, firmly connected with the table
carrier 15 adapted to turn about 36, in order that the rod 6, when the table A is
laid back to the position shown in dotted lines, Fig. 7, may follow this movement.
The screw 23 has for its object' to enable the backward movement of the marks b
to be adjusted exactly according to the movement of the fingers c.
In order to permit of a lateral movement or displacement of the eccentric 31 with
the curved paths 8, s¹, n, the eccentric is supported by two guides 16, in the
frame 30 of the machine. The guides 16, extend through the frame 30 and are on
the outside connected by the bridge piece 17.
This bridge piece 17 carries a bolt 18, to which is attached a fork 19, secured
between supports 20, on a bolt 21, which receives by the rod 22 its motion from an
eccentric provided upon the same shaft which carries the mark eccentric.
When the catch 'seizes the sheet laid on, the roller of the lever r runs on to s¹,
and m runs on to the path n (Fig. 3) whereby the catches are closed through the
seginent o and gearing k and lever m.
When the catches i have been opened for transferring the printed sheet to the
drum D, the rod 22 is raised, and the eccentric 31 with the paths s s' and n is
drawn outwards by the fork 19 to such an extent that the roller of the lever r
passes behind the path s', the catches thus remaining open.
When the next sheet laid on is to be seized the fork 19 moved by the rod 22,
the eccentric 31 shifts inwards at the moment when the roller passes to the same
position, which it occupied when the eccentric 31 was moved outwards, then the
roller runs on to s¹ m¹ on to the path n and the catches i are closed to seize the
next sheet.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. A rotary printing press for lithographic printing plates of aluminium, zine or
other suitable metal, comprising a plate-roller and press-roller of dimensions in a
proportion of three to two baving equal circumferential velocity and having
respectively one third and one half of the surfaces arranged to co-operate, and
having the remainder of their surfaces set back, substantially as described and for
the purpose set forth.
2. A rotary printing press for lithographic printing plates of aluminium, zinc or
other suitable metal, comprising a plate-roller and press-roller of dimensions in a
proportion of three to two having equal circumferential velocity and having
respectively one third and one half of the surfaces arranged to co-operate, and
baving the remainder of their surfaces set back, and co-operating with moistening
rollers, having a surface of rubber and covering of a fabric adapted to hold
moisture.
3. A rotary printing press for lithographic printing plates of aluminium, zine or
other suitable metal, comprising a plate-roller and press-roller of dimensions in
a proportion of three to two, having equal circumferential velocity and having
respectively one third and one half of the surfaces arranged to co-operate, and
having the remainder of their surfaces set back, in combination with marks b,
sliding lengthwise on an oscillating rod a, being adjustable by set screw f for the
purpose set forth.
4. A rotary printing press for lithographic printing plates of aluminium, zinc, or
other suitable metal, comprising a plate-roller and press-roller of dimensions in a
proportion of three to two having equal circumferential velocity and having
respectively one third and one half of the surfaces arranged to co-operate, and
having the remainder of their surfaces set back, in combination with grippers i

page_text: closed by cam n and arm m on the gripper bar, and opened by cams s, s², toothed
sector 0, and pinion k on the gripper bar, substantially as described.
5. A rotary printing press for lithographic printing plates of aluminium, zinc or
other suitable metal, comprising a plate-roller and press-roller of dimensions in a
proportion of three to two having equal circumferential velocity and having
respectively one third and one half of the surfaces arranged to co-operate and
having the remainder of their surfaces set back, in combination with pipe w having
openings v into which pipe air is pressed for the purpose set forth.
Dated this 10th day of Anril 1805
S. S. BROMHEAD,
97 Newgate Street, E.C., Agent for Applicant.