Printing – Planographic – Dampeners
Reexamination Certificate
1998-07-23
2001-10-16
Bennett, Christopher A. (Department: 2854)
Printing
Planographic
Dampeners
C101S247000, C101S218000, C101S352040
Reexamination Certificate
active
06302019
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to dampeners used in printing presses. In particular, the present invention relates to skewing mechanisms used with dampeners in a web-fed offset printing press.
2. Description of the Prior Art
Prior art web-fed offset printing presses have included dampeners which are used to provide, and adjust, an amount of water, which is mixed with a fountain solution, onto the web being printed. Examples of upper UD and lower LD dampeners used in a prior art web-fed offset printing press unit P are shown schematically in FIG.
1
. The dampeners UD and LD transfer water to upper plate UP and lower plate LP, respectively, which in turn transfer water to opposite sides of the web W being printed. The upper and lower plates UP, LP transfer an inked image to upper and lower blankets UB, LB, which transfer the inked image to opposite sides of a web W.
Webs having different widths will require different amounts of water be transferred to the web surface during printing. It is known in the art that skewing a skew or pan roll relative to an adjacent slip roll in a dampener can be used to regulate the amount of water which is transferred from a dampener pan to the web. This skewing, therefore may be used to adjust the dampener so that the proper amount of water is supplied to a web of a particular width. If a skew adjustment is not made upon the change in width of the web, it is possible that an inappropriate amount of water will be delivered to the middle section of the web versus the edges, which can result in poor-quality printing or web breakage.
FIGS. 2
a
and
2
b
show the upper dampener UD and/or lower dampener LD of
FIG. 1
having two different positions of an end of skew or pan roll PN relative to slip roll SL. In
FIG. 2
a,
one end of the skew or pan roll PN is in a first position A relative to slip roll SL, while in
FIG. 2
b,
one end of the skew or pan roll PN is in a second position B relative to slip roll SL. In the prior art device of
FIGS. 1
,
2
a
and
2
b,
an end of the skew or pan roll PN can have an infinite number of positions relative to the slip roll SL, because those positions are adjusted using a skew adjustment rod RS described below. As is known in the art, a dampening agent D, preferably water (with a fountain solution), is conveyed from a pan P by rotation of skew or pan roll PN. Slip roll SL transfers the dampening agent D, from skew or pan roll PN to vibrator roll DV, then to form roll DF and then to the plate UP or LP.
The steps used to make a skew adjustment for a prior art lower dampener LD are shown in
FIGS. 3
a
-
3
d.
In a first step, a wrench R is used to loosen a skew mechanism lock nut (not shown), by rotation in a direction S
1
. The skew mechanism lock nut is used to lock the entire skew mechanism in a particular position. In a second step, wrench R is used to loosen a skew adjustment rod lock nut LN, by rotation in a direction S
2
. The lock nut LN is used to secure a skew adjustment rod RS in a particular position. In a third step, wrench R is used to rotate the skew adjustment rod about its longitudinal axis, in a direction S
3
(direction S
3
is shown, for representation purposes, in a different plane in
FIG. 3
c
). Rotation of skew adjustment rod RS about its longitudinal axis moves the pan roll PN angularly around slip roll SL. As is known in the art, the pan roll PN is pivotally mounted on a bracket for angular movement relative to slip roll SL. The skew adjustment rod RS has a bolt head BH upon which wrench R is mounted to rotate skew adjustment rod RS, and rotation of skew adjustment rod RS, in cooperation with threads on skew adjustment rod RS adjusts the skew adjustment rod RS in and out, to thereby move the skew or pan roll PN to an appropriate skew position. Finally, the wrench R is used to tighten the skew adjustment rod lock nut LN and the skew mechanism lock nut, in steps S
4
, S
5
, to lock the skew mechanism in its newly adjusted position. These adjustment steps are required for each upper and lower dampener UD, LD in each printing unit.
SUMMARY OF THE INVENTION
The apparatuses and methods for adjusting dampener skewing in prior art web-fed offset printing presses entail a number of different steps which must be manually made by the press operator, which can result in a time-consuming process each time that the width of the web is changed, or any other time that adjustment of the skewing of the dampener is required. Because of the time necessary to make the appropriate steps and adjustments to change the skew every time the width of a web is changed, operators frequently do not make the proper skew adjustment. As a result, too much or not enough water is transferred to the new web, which can result in poor printing quality or web breakage.
It is desirable to reduce the amount of time required for adjusting skew in the dampeners in a web-fed offset printing press to thereby reduce press down-time, or the chance that adjustments will not be made and an improper amount of water transferred to the web. The present invention is a method and apparatus which significantly simplifies and speeds up the process of adjusting dampener skewing in a web-fed offset printing press, or any other press. As a result, the present invention reduces down time and simplifies adjustment, such that the operator will be more likely to make the proper adjustment so that an appropriate amount of water is transferred to the web.
In the method and apparatus of the present invention one or more skew adjustment linkages connect skew adjustment rods for the upper and lower dampeners of each printing unit. The linkage ensures that a single movement by the operator will allow adjustment of the skewing of both the upper and lower dampeners at the same time. The linkage or linkages are preferably connected at one end to skew adjustment brackets, which in turn are connected to a skew adjustment rod for one of the upper or lower dampeners. The skew adjustment rod adjusts the amount of skew of an associated pan roll. In this manner, movement of the linkage controls the skew of both the upper and lower dampener pan rolls simultaneously.
Movement of the linkage may be controlled by movement of a spring plunger bracket, which is connected to the linkage or linkages. A spring plunger on the spring plunger bracket may be spring biased, and may be adjusted and locked into different skew setting positions using a pin-hole arrangement. A web width indicator associated with the spring plunger bracket may be used to guide the operator to an appropriate skew setting for a particular web width. The skew adjustment mechanism may also include a fine tuning mechanism, used to make minor adjustments to the skew settings for the dampeners, for example, when a particular setting is between one of the settings established by the pin-hole arrangement. This fine tuning mechanism can either individually or simultaneously allow fine tuning adjustment of the skew setting.
REFERENCES:
patent: 2570242 (1947-05-01), James
patent: 4301728 (1981-11-01), Jaffe et al.
patent: 4369705 (1983-01-01), Gelina
patent: 4458590 (1984-07-01), Egnaczak et al.
patent: 0 105 477 (1984-04-01), None
patent: 1 278 881 (1972-06-01), None
patent: 2 038 243 (1980-07-01), None
patent: 2 212 106 (1989-07-01), None
Arthur Hilner, “Diagonal oder ähnliches...,” Deutscher Drucker, Bd. 24, No.11, Apr. 7, 1988, p. 15.
Burke David Charles
Elkinson Brian Robert
Palmatier Roland Thomas
Zabkar Clifford Allen
Bennett Christopher A.
Heidelberger Druckmaschinen AG
Kenyon & Kenyon
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