Printing – Inkers – Fountains
Reexamination Certificate
2002-05-17
2004-05-25
Hirshfeld, Andrew H. (Department: 2854)
Printing
Inkers
Fountains
C101S350500, C101S425000, C101SDIG029
Reexamination Certificate
active
06739256
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method of printing corrugated board sheets, and more particularly to a method of preventing ink for printing presses from increasing in viscosity and a printing press for use in practicing the method.
BACKGROUND OF THE INVENTION
The flexographic printing method wherein an aqueous ink is used for printing corrugated board sheets has the advantage that the ink dries rapidly, permitting the sheet to be fed directly to the subsequent step such as stamping immediately after printing.
FIG. 9
is a side elevation of a conventional flexographic printing press, and
FIG. 10
is a fragmentary perspective view of the same (see the specification of JP-A No. 5-200986/1993). An inking roll
1
and a squeeze roll
2
are in contact with each other, and an ink reservoir
11
in the form of a groove is formed between the two rolls
1
,
2
. Disposed under the inking roll
1
in contact therewith is a plate cylinder
9
provided with a printing plate
90
. A support roll
91
is disposed under the plate cylinder
9
. The inking roll
1
is movable toward or away from the plate cylinder
9
. When the two rolls
1
,
2
are rotated in ink squeezing directions (inward directions), the ink on the surface of the inking roll
1
is transferred to the printing plate (not shown) attached to the plate cylinder
9
, printing a corrugated board sheet S fed to the nip between the plate cylinder
9
and the support roll
91
.
With reference to
FIG. 10
, the ink is supplied from a container
96
placed on the floor to the ink reservoir
11
via a pump
97
, supply pipe
94
and supply nozzle
4
. The ink for use in flexographic printing presses readily dries and therefore becomes solidified due to a rise in viscosity unless incessantly held in circulation. Accordingly, the ink flowing out from the ends of the two rolls
1
,
2
is received by ink pans
98
,
98
and collected in the container
96
through a return pipe
95
for continuously circulating the ink during printing. The return pipe
95
and the supply pipe
94
are over 8 m in length.
The ink invariably partly remains in the return pipe
95
and the supply pipe
94
without being fully collected in the event of a change of ink, for example, for a color change. The remaining portion of ink is washed away and discarded during cleaning. Further because the path of circulation of the ink is long, a large amount of liquid waste is produced by cleaning the path, consequently necessitating great equipment for treating the liquid waste. This entails the problem that the liquid waste treatment requires great initial cost and running cost.
FIG. 8
shows a printing press comprising a closed box
3
which is slidable along an ink reservoir
11
and which has incorporated therein a removable ink tank
31
and is provided with an ink supply nozzle
4
(see U.S. Pat. No. 5,697,299).
An object of the present invention is to provide a printing method wherein a flexographic ink is used and yet which does not require a long circulation path, prevents the ink from increasing in viscosity, diminishes the waste of ink in the event of a change of ink and does not necessitate any great equipment for the treatment of cleaning liquid waste, and more particularly to provide a method of preventing ink from increasing in viscosity and a printing press for use in practicing the method.
SUMMARY OF THE INVENTION
The present invention provides a method of printing by a printing press wherein an ink is supplied from an ink supply-aspiration nozzle
4
to an ink reservoir
11
provided between an inking roll
1
and a squeeze roll
2
pressed into contact with the inking roll
1
, and the ink is transferred from the inking roll
1
to a printing plate attached to a plate cylinder
9
by the rotation of the inking roll
1
, the ink supply-aspiration nozzle
4
being connected to a closed box
3
housing an ink tank
31
therein, the closed box
3
and the ink supply-aspiration nozzle
4
being movable along the ink reservoir
11
. The printing method is practiced by repeatedly performing the steps of:
supplying the ink from the supply-aspiration nozzle
4
to the ink reservoir
11
at a location above the ink reservoir
11
, i.e., at a midportion thereof,
moving the supply-aspiration nozzle
4
from the location along the ink reservoir
11
, thereafter halting the nozzle
4
and causing the nozzle
4
to aspirate a predetermined amount of ink from the ink reservoir
11
to place the aspirated ink into the ink tank
31
within the closed box
3
and produce a flow of ink in the ink reservoir
11
,
further moving the supply-aspiration nozzle
4
from the halted location along the ink reservoir
11
and causing the nozzle
4
to aspirate a predetermined amount of ink from the reservoir
11
to place the aspirated ink into the ink tank in the closed box
3
and produce a flow of ink in the ink reservoir
11
.
A diluting liquid is supplied to the ink reservoir
11
while performing the above steps.
After supplying the ink, the supply-aspiration nozzle
4
is moved first toward one end of the ink reservoir
11
, and subsequently toward the other end of the reservoir
11
.
When the nozzle
4
aspirates the ink from one end portion of the ink reservoir
11
and places the ink into the ink tank
31
within the closed box
3
, the liquid level of the ink lowers at the end portion, permitting the ink to flow toward the end portion. Since like step is also performed at the other end portion of the reservoir
11
, the ink similarly moves along the reservoir
11
toward the other end portion. Ink is then supplied to the reservoir at a location away from the two end portions. A flow of ink also occurs at this time.
Since the above cycle is repeated during the printing operation, the ink incessantly flows in the ink reservoir
11
, which is continuously stirred, whereby the ink is prevented from increasing in viscosity. Especially because the ink flows between the opposite end portions of the ink reservoir
11
, the ink moves over an increased distance and is stirred effectively. The diluting liquid supplied for replenishment is thoroughly mixed with the ink owing to the stirring effect produced by the flow of ink.
The ink supply-aspiration nozzle
4
is slidable with the closed box
3
removably housing the ink tank
31
therein, so that the pipe channel between the nozzle
4
and the closed box
3
can be shortened. This prevents the ink from increasing in viscosity without necessitating a long circulation path conventionally required, consequently greatly diminishing the waste of ink to be involved in changing the ink and permitting liquid waste treatment at a much lower cost than conventionally.
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Kubo Tadao
Murakawa Ichiro
Eckert Seamans Cherin & Mellott , LLC
Hinze Leo T.
Lang IV William F.
Silverman Arnold B.
Umetani Mfg. Co., Ltd.
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