Improvements in Printing Machines.
Year: 1899

page_text: Date of Application, 20th June, 1899-Accepted, 26th Aug., 1899
Improvements in Printing Machines.
I, GEORGE CROYDON MARKS, of 18, Southampton Buildings, Chancery Lane,
London, Middlesex, Consulting Engineer and Patent Agent (a communication
from abroad by Irving Lee Stone, of Battle Creek, Calhoun County, Michigan,
United States of America, Engineer), do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement:-
This invention is an improvement in printing machines of that class wherein
a web of paper is printed on both sides by means of impression cylinders rolled
back and forth over stationary type beds.
*
The object of the present invention is to prevent smutting or smearing of the
sheets on the second cylinder by providing an adjustable "tympan" web or off-
set web" for the second cylinder, which tympan prevents the printed side of the
sheet coming in contact with the surface of the impression cylinder and such
tympan can be shifted at intervals from one tympan roll to the other so as to
bring a clean portion of the tympan under the cylinder and thus in a manner
well understood by printers prevent off-set and increase the capacity of the press
and the quality of the work produced therefrom.
In my invention, the tympan web is supported above the upper bed of the
press and extends beneath the upper cylinder and between it and the paper web.
The ends of the tympan are wound upon spools or rollers and mechanism is pro-
vided by which the tympan may be shifted lengthwise and unwound from one
roller and wound upon the other, and after it is all unwound from one roll its
motion may be reversed and it may be rewound upon the other.
The invention is applicable to various forms of flat bed cylinder presses, and is
particularly designed for use with the "Cox-Duplex" presses.
The accompanying drawing illustrates the invention as applied to the upper
or perfecting cylinder of such a press, but I do not limit myself to its employ-
ment in such press as it is applicable to various other forms of web printing
machines.
The said drawing represents partly in side elevation and in section the print-
ing mechanism of one of said Cox-Duplex presses, with my improved tympan
mechanism applied thereto.
Referring thereto, h, h, are the type beds; H. H₁ the rolling cylinders
co-operating therewith: M. M', m, m¹. stationary web guiding rollers, and 1,7.
movable web looping rollers, all such parts being constructed, arranged and
operating substantially as in said Cox-Duplex presses. K. K are vertically
morable bars connected to rocking levers i, j, carrying pawl that operate the
rollers I of the ink fountains, said bars being alternately depressed (by means
of cams on the reciprocating cross-heads in which the cylinders are journaled),
and uplifted by springs .

page_text: Our tympan roll T is supported in brackets T attached to the frame above
looping roller M, and the other tympan roll is supported in brackets t¹ mounted on
the frame above roller m. The tympan sheet is led from roll t to roll T above
the upper part of the printed web and passed down under cylinder H' between
it and the web, being guided to and from the cylinder over rollers U, U,
mounted on the carriage and rollers W, w, mounted on the frame as shown.
By this arrangement it will be at once seen that the tympan web is interposed
between the surface of the upper cylinder and the printed paper web, and that
the cylinder rolls back and forth over the tympan web pressing it and the under-
lying paper web down upon the type, the tympan web preventing the printed
paper web contacting with the cylinder.
The tympan may be gradually shifted from one roll to the other to present
clean surfaces to the impressions upon the web. The amount of shifting of
tympan and the times of shifting it can be easily varied or regulated to suit
the will of the constructor.
Preferably the tympan is shifted from roll to roll T because that movement of
the tympan will correspond to the direction of movement of the paper web. The
roll therefore may be provided with a friction disk (namely a disc held in
frictional contact with the end of the roll) or other suitable device to prevent its
unwinding by momentum. On the shaft of roll T is a ratchet V, engaged by a
stop dog and by a pawl, on a loose gear wheel or pinion which is
vibrated by means of a rack W the lower end of which is pivotally connected
to an extension 3 of the adjoining fountain lever as shown. The rod W₁ may
have an adjustable connection with extension as indicated in the drawings.
This is one simple construction by which the tympan can be intermittently
shifted from roll t to roll T. Obviously either or both rolls T, t, could be thus
mechanically operated. I do not, however, confine myself to such roll shifting
mechanism, as it can be easily varied according to the construction of press,
or wishes of the press constructor.
In the press shown it is most advantageous to operate the tympan roll at the
ends of the strokes of the cylinders, as at that time the web is moving from
roll m toward roll M and thus there is the least liability to smear the freshly
printed sheet.
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 a web printing press, the combination of a reciprocating cylinder, and
tympan web therefor, and supports for the ends of the tympan located exterior
to the cylinder with means independent of the means employed for shifting the
paper web for intermittently shifting the tympan after impressions.
2. In-a web printing press, the combination of a reciprocating impression
cylinder, a tympan web therefor having its ends wound upon supports exterior
to and independent of the cylinder, and interposed between the cylinder and the
paper web, and means independent of the means employed for shifting the paper
web for intermittently shifting the tympan web, from one support to the other,
after impressions and holding that portion of the tympan over the forms
stationary with the paper web during the taking of an impression.
3. In a web printing, press, the combination of a type bed, an impression
cylinder, means for reciprocating the impression cylinder over the bed and means
for leading a web of paper to be printed between said bed and cylinder: with a
pair of tympan supporting guides mounted upon the frame of the machine beyond
the range of travel of the cylinder, a tympan extending from one guide to the
other and interposed between the cylinder and paper web, and a mechanism sub-
stantially as described for shifting said tympan from one support to the other
said mechanism being operated by the movement of the cylinder carriage and
only after impressions for the purpose and substantially as described.

page_text: 4. An adjustable tympan for stationary bed rolling cylinder web printing
presses and mechanism for operating such tympan substantially as shown in the
drawings and described with reference thereto."
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and 25, Cross Street, Manchester,
Agents..