IM- PROVEMENTS IN LITHOGRAPHIC APPARATUS OR PRESSES
Year: 1878

page_text: LETTERS PATENT to Théodore Dupuy, of the Firm of Th. Dupuy et Fils, of
Rue des Petits Hotels, No. 22, at Paris, Printers, for the Invention of "IM-
PROVEMENTS IN LITHOGRAPHIC APPARATUS OR PRESSES."
Sealed the 17th January 1879, and dated the 29th July 1878.
PROVISIONAL SPECIFICATION left by the said Théodore Dupuy at the Office
of the Commissioners of Patents on the 29th July 1878.
THÉODORE DUPUY, of the Firm of Th. Dupuy et Fils, of Rue des Petits Hotels,
No. 22, at Paris, Printers. "IMPROVEMENTS IN LITHOGRAPHIC APPARATUS OR
PRESSES."
This Invention relates to lithographic presses of the kind in which a scraper is
made to pass with considerable pressure over a tympan covering the sheet to be
printed as it lies on the lithographic stone or plate.
The mechanism of the press, constructed according to this Invention, is so
arranged as to produce the following succession of operations.
First. The scraper passes along the forme, pressed down on the tympan, which
is a flexible sheet of leather, unrolled by the movement of the scraper as it advances,
so that it has no movement relatively to the forme.
Secondly. The scraper makes its back stroke in an elevated position, so that it
exerts no pressure on the forme.
Thirdly. The forme passes under the moistening and then under the inking
rollers.
During the second and third operations the sheet is removed from the forme,
being gradually raised therefrom by the attendant as the scraper retires.
Fourthly. The forme moves back to the position for impression, the moistening
rollers being raised by a cam during this movement, so as not to moisten the forme
after it has been inked.

page_text: During this back stroke of the forme, the attendant puts a fresh sheet in position
for being fed, and when that stroke is completed he places it on the register pins,
whereupon the series of operations is repeated.
While these successive operations are taking place, the ink table continues to
reciprocate, distributing the ink on the ink rollers, and rendering their coating thin
and uniform, so that they ink the forme with great delicacy.
In the gearing and mechanical connections provided for effecting the required
movements, a countershaft is arranged to make one revolution which completes an
impression for every four strokes of the ink table, the necessary cams to give the
various movements being fixed on this countershaft.
For moving the scraper, a pair of rods, one at each side of the press, are secured
at their one end to the scraper frame, and their other ends are made by means of a
cam to engage with and to be disengaged from the ink table, so that during a
to-and-fro stroke of the latter the scraper is caused to make its double stroke and
then to rest.
In like manner the forme table is at the proper times attached to and detached
from the ink table.
In order to give the scraper its required pressure during its impressing stroke,
rollers mounted on the scraper frame are caused to run under guide bars sloped at
the ends, and during the back stroke of the scraper these bars are moved aside, the
scraper being then raised by springs off the tympan.
In order to provide the required inclines at each end of the pressing bars to suit
different sizes of sheets, these bars are divided longitudinally, and one half is slid
along the other so as to make the whole length greater or less, as may be required.
In order to raise the register pins when the forme moves, the frame carrying
them has under it wedge pieces attached to the scraper frame, so that as the scraper
completes its back stroke it draws back these wedge pieces and so causes the pins
to be raised during the movement of the forme.
In order to prevent movement of the tympan relatively to the forme, the one end
of the tympan is fixed to a bar which is caught by brackets projecting from the
forme table, so that as the scraper advances that end of the tympan is held station-
ary, the tympan unrolling itself from a roller carried by the scraper frame.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Théodore Dupuy in the Great Seal Patent Office on the 20th January
1879.
THÉODORE DUPUY, of the Firm of Th. Dupuy et Fils, of Rue des Petits Hotels,
No. 22, at Paris, Printers. "IMPROVEMENTS IN LITHOGRAPHIC APPARATUS OR
PRESSES."
This Invention relates to lithographic presses of the kind in which a scraper is
made to pass with considerable pressure over a tympan covering the sheet to be
printed as it lies on the lithographic stone or plate.
The mechanism of the press, constructed according to this Invention, is so
arranged as to produce the following succession of operations.
First. The scraper passes along the forme, pressed down on the tympan, which
is a flexible sheet of leather unrolled by the movement of the scraper as it advances,
so that it has no movement relatively to the forme.
Secondly. The scraper makes its back stroke in an elevated position, so that it
exerts no pressure on the forme.
Thirdly. The forme passes under the moistening and then under the inking
rollers.
During the second and third operations the sheet is removed from the forme,
being gradually raised therefrom by the attendant as the scraper retires.
Fourthly. The forme moves back to the position for impression, the moistening
rollers being raised by a cam during this movement so as not to moisten the forme
after it has been inked.
During this back stroke of the forme, the attendant puts a fresh sheet in position
for being fed, and when that stroke is completed he places it on the register pins,
whereupon the series of operations is repeated.
While these successive operations are taking place, the ink table continues to
reciprocate, distributing the ink on the ink rollers, and rendering their coating thin
and uniform, so that they ink the form with great delicacy.
In the gearing and mechanical connections provided for effecting the required
movements, a countershaft is arranged to make one revolution, which completes an
impression for every four strokes of the ink table, the necessary cams to give the
various movements being fixed on this countershaft.
For moveing the scraper, a pair of rods, one at each side of the press, are
secured at their one end to the scraper frame, and their other ends are made, by
means of a cam, to engage with and to be disengaged from the ink table, so that
during a to-and-fro stroke of the latter the scraper is caused to make its double
stroke and then to rest.
In like manner, the forme table is at the proper times attached to and detached
from the ink table.
In order to give the scraper its required pressure during its impressing stroke,
rollers mounted on the scraper frame are caused to run under guide bars sloped at
the ends, and during the back stroke of the scraper these bars are moved aside,
the scraper being then raised by springs off the tympan.
In order to provide the required incline at each end of the pressing bars to suit
different sizes of sheets, these bars are divided longitudinally, and one half is slid
along the other so as to make the whole length greater or less, as may be required.
In order to raise the register pins when the forme moves, the frame carrying
them has under it wedge pieces attached to the scraper frame, so that as the scraper
completes its back stroke it draws back these wedge pieces and so causes the pins to
be raised during the movement of the forme.
In order to prevent movement of the tympan relatively to the forme, the one end
of the tympan is fixed to a bar which is caught by brackets projecting from the
forme table, so that as the scraper advances that end of the tympan is held station-
ary, the tympan unrolling itself from a roller carried by the scraper frame.

page_text: DESCRIPTION OF THE DRAWINGS.
Fig. 1 represents a longitudinal section, and Fig. 2, a plan of a lithographic press,
according to this Invention; Fig. 3 is a part longitudinal section, taken on the
line I, J, K, L, M, of Fig. 2, and Fig. 4 is a transverse section on A, B, C, D, E,
F, G. H; Figs. 5 and 6 are transverse sections on U, V; and S, T, respectively.
Rotary notion being given to the shaft A (Fig. 4), the inking table is caused to
reciprocate, and the pinion a makes half a revolution at the end of each stroke of
the table. By means of gearing b and c, in the proportion of 1 to 2, a shaft B is
driven at half the speed of a, making, therefore, one revolution, which corresponds
with one complete impression for every four strokes of the ink table.
From the shaft B are driven most of the moving parts producing the successive
steps of operation above mentioned in the following manner :-
First. For advancing the scraper R, the bars c (Figs. 2 and 5), extending from it,
are hooked to the ink table in a manner similar to that employed for working the
cylinder of lithographic cylinder presses; two forked levers d, worked by suitable
cams on the shaft B, seize the ends of the bars c, and begin their movement.
Meanwhile the slide e, worked by inclines on the framing, is slid transversely on
the ink table so as to seize by its teeth g the forks h, the scraper being thus for the
time attached to the ink table and caused to make its forward stroke along with it.
During this stroke, the levers d, remaining stationary in the position where they
left hold of the bars c at the beginning of the stroke, are ready to seize them again
on their return.
The scraper, still attached to the ink table, makes its return stroke, which consti-
tutes the second movement, the cams on the shaft B having a dwell during this
period, until just at the end of the movement, when they cause the forked levers d
to re-engage with the bars and complete their back stroke.
The third movement is applied to the forme in the same manner as the first is
applied to the scraper. At its beginning, the slide e, making its regular stroke
under the ink table, seizes the forme table X as it had seized the scraper bars, but
not unless the fork h be moved at the same time as the tooth g of the slide, without
which motion the tooth ? does not meet the fork h and consequently does not
engage with it, a condition that in this third movement obtains in respect of the
scraper bars, so that the scraper remains stationary.
At the beginning of the third movement a cam causes the damping rollers to
descend, so that the forme is damped in passing under them on its way to the
inking rollers.
The fourth movement, the return stroke of the forme, is effected in the same
way as the return stroke of the scraper, the damping rollers being in the first
place raised by their cam so as not to damp the forme after it has been inked.
The mechanism for giving pressure to the scraper is as follows:-At first the
the scraper is raised by the springs (Fig. 5), but when the scraper begins its
forward stroke the rollers i, Fig. 5, coming under the guide rails j of the forme
table are depressed by inclines on these rails, causing the scraper to bear down on
the forme X. During the return stroke, the rollers i pass under guide rails
having reverse inclines which allow the scraper to rise in obedience to the springs r,
The alteration of the guide rails for this purpose is effected by displacing them
laterally by means of levers K worked by cams on the shaft B.
The inclines for the descent and ascent of the scraper have to be so arranged that
it shall escape the register frames at n, n¹ so as not to crush them. In order to suit
this movement in various positions of these frames corresponding to various lengths
of impressions the following arrangement is adopted:-The one set of registers n¹ is
fixed, never varying in position, the other set n being moveable and set to suit the
length of impression.
The inclines i, j, are adjusted in their length to suit the position of the registers n,
and for this purpose they are made in two pieces k, k², (Fig. 5), cach being of length

page_text: equivalent to the shortest impression, and both lengths taken together being equi-
valent to the longest impression, these extremes allowing all intermediate lengths.
One of the pieces in each case shifts with the requisite frame n and is fixed to
the support by the same pin, so that the total length necessarily corresponds
with that of the forme.
The register pins at 8, s¹, (Fig. 3), have their up-and-down movement effected by
inclines p, p, on a rod pressed in the one direction by a spring 1, and in the other
by the scraper when it is at the extreme of its back stroke, so that the pins are
withdrawn when the scraper is moving over the forme.
The forme abuts firmly against forked levers t, which, when the scraper advances,
hold the bar u to which is attached one end of the leather tympan D, while the
tympan is unwound from its roller. Thus the tympan, as it is stretched by the
movement of the scraper over it, is prevented from shifting relatively to the forme.
The scraper is adjusted in height by setting screws in the usual way, and may
be pressed down by springs to give elastic pressure.
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I claim,―
First. The method herein described of effecting lithographic machine printing by
four successive operations for each impression.
Second. The herein-described arrangement and construction of the lithographic
printing machine, operating in the manner referred to in the preceding claim.
Third. Effecting the pressure and relief of the scraper by causing rollers mounted*
on its frame to run along laterally shifting guide rails having inclines, as herein
described.
Fourth. Making each of the said guide rails in two parts, one part having the
same fixture as one of the register frames, so as to adjust the length of the rails to
that of the impression, and avoid damaging the registers, as herein described.
Fifth. Moving the register points vertically, by inclines worked by springs in the
one direction, and by the return stroke of the scraper in the opposite direction, as
herein described.
Sixth. Securing the end of the tympan to the abutment of the forme table so
as to prevent movement of the tympan relatively to the forme, as herein described.
In witness whereof, I, the said Théodore Dupuy, have hereunto set my hand
and seal, this Seventh day of January, in the year of our Lord One thou-
sand eight hundred and seventy-nine.
Witness,
JULES ARMENGAUD, Jeune,
Of Paris,
Bd. de Strasbourg, 23,
Civil Engineer.
THEODORE DUPUY. (L.S.)