IMPROVEMENTS IN APPARATUS FOR DAMPING PAPER FOR PRINTING
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by John Gray at the Office of the
Commissioners of Patents, with his Petition, on the 20th September
1873.
I, JOHN GRAY, Knt. and M.P., of Charleville House, in the County of
Dublin, Ireland, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN APPARATUS FOR DAMPING PAPER FOR PRINTING," to be as
follows:-
The nature of my said Invention of an improved apparatus is sub-
stantially as follows; the improvements are more especially applicable
to printing machines which print from the web or roll of uncut paper :-
I place two suitable cylinders turned true, by preference metallic, at the
feeding end of the machine, and between the web or roll of paper and
the printing machine. These cylinders are made by suitable gearing to
revolve in close proximity to each other in opposite directions. On each
of these I place an endless web of blanket or other soft absorbent
substance, as woollen or other felt, or other similar soft and absorbent
substance, as flannel or printing blanket. This endless blanket is passed
round another revolving cylinder, by preference of smaller diameter, so
as to work from one cylinder to the other round both, revolving with the

page_text: cylinders somewhat in the same way as a papermakers' wire gauze
passes from end to end, and round the cylinders at each end of a paper
machine, or as a common driving belt passes round the pulley on the
motion wheel and the pulley on the main shaft.
The two cylinders near the machine are adjustable by means of screws b
and levers, and can be made to press against each other with more or
less force, and can have all pressure removed when the printing machine
is stopped so as not to continue the damping, and so cause excess and
weakness, and so induce breakage of the paper web.
The other cylinders round which the endless blankets pass are placed 1
about two or three feet from the first described, and somewhat further
from the printing machine, the upper one on a considerably higher, and
the lower one on a considerably lower level than its corresponding
cylinder nearer to the machine. These endless blankets are damped to a
suitable degree to cause the web of paper, which is caused to pass 1
between the two cylinders next the machine, and pressed as it passes
with their revolutions between them covered with their damp blankets,
so as to be itself sufficiently damped to be in a proper condition for
being suitably printed on by type, stereotype, cuts, engravings, or other
such adjustments. When it is passed through the printing or impressing 2
portion of the machine I maintain the proper degree of dampness in
these revolving endless blankets by placing in suitable positions on
brackets over them shallow troughs containing water, having dipped into
them strips of flannel or other absorbent fabric of the length of the
breadth of the paper to be damped and printed on. These strips of 2
flannel may vary in breadth, but I find a convenient breadth to be from
about six to twelve inches, and they have one edge overhanging the lip
of the trough, and touching and sweeping the endless blanket as it passes
by under them.
The capilliary attracting of the absorbent slips draws up and over the 3
lip of the trough water from the trough, and delivering it in an equable
and hardly varying quantity maintains the regular amount of dampness
in the endless blanket to impart the proper dampness to the paper. The
amount of water drawn up and delivered thus may be regulated at
pleasure. It can be increased by adding one or more strips of flannel, 3
the out-hanging edge of each added one being by preference placed upon

page_text: house does over another, each superincumbent one so added giving its
capilliary water to the one underneath it, and so in succession till the
lower one receives and delivers equally to the endless blanket the water
received by all. The quantity can be lessened by diminishing the
number of strips as found requisite. The quantity of water allowed to
pass thus to the blanket ought to correspond as nearly as possible to the
quantity of water carried off by the passing paper and the quantity
evaporated.
The cylinders next the machine with their damp coverings when
suitably regulated press the water evenly into the two surfaces and
partly into the body of the paper, and thus the paper is prepared by
regulated damping for perfect printing in its transit from the dry roll to
the printing cylinder without loss of time or extra labour.
The Invention can be carried out in other ways. The cylinders next
the machine may each be covered by a light blanket, as on some
printing cylinders, and the water supplied from the trough by means of
strips of flannel direct to these blanketted cylinders in suitably measured
and regulated quantities. A screw bar with proper adjustments applied
along the lip from which the strips of flannel depend may be made by
adjusted pressure to regulate the quantity of water drawn over with
great accuracy, so as to maintain the proper amount of dampness in the
blankets, so as not to alter the quantity imparted from or by them to the
paper.
In some cases I alter the amount of water let over in proportion to
the rapidity with which the passing web of paper is carried through the
apparatus and to the printing cylinder.