Printing – Inkers – Roller
Reexamination Certificate
2000-02-01
2002-07-30
Eickholt, Eugene (Department: 2854)
Printing
Inkers
Roller
C101S352010
Reexamination Certificate
active
06425326
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to an inking unit in a printing machine, more particularly, having a throw-off device for throwing an ink applicator roller group off a plate cylinder.
The published German Patent Document DE 37 103 00 A1 describes a switching device for inking unit rollers in printing machines, wherein, by actuating an operating cylinder, two intermediate rollers can be lifted off distributor cylinders, so that ink flow continues only via the two first applicator rollers. In this switching state of the inking unit, two strands or ribbons of ink are provided with the task of continuing to even out the ink applied by the two first applicator rollers. Although, in the aforenoted switching state, no ink flow takes place over the applicator rollers associated with the two strands or ribbons of ink, these applicator rollers and, consequently, all of the applicator rollers, are also thrown onto the plate cylinder. An applicator roller throw-off cam is pivotable as a result of the actuation of another operating cylinder, so that all the applicator rollers can be thrown off the plate cylinder.
A disadvantage of the aforedescribed switching device is that the inking unit reacts sluggishly to changes in the inking, because a predetermined volume of ink is always stored in the two strands or ribbons of ink used to even out the applied ink, and this volume only very slowly equalizes any corrections that are necessary and, as a result of this sluggishness, is the cause of paper wastage. In addition, the inking unit also requires a comparatively great amount of time for being set to the respective printing jobs.
The published German Patent Document DE 42 30 090 C2 describes an inking unit for printing machines that is operatable as a so-called short or anilox inking unit, in that the printing plate is inked only via a first ink applicator roller group, and a second ink applicator roll group is lifted off the plate cylinder by a throw-off device. With respect to this inking unit, Although the deficiencies associated with the switching device described hereinbefore in the published German Patent Document DE 37 103 00 A1 are no longer present in that of the published German Patent Document DE 42 30 090 C2, the latter does not describe any specific throw-off device that is suitable for lifting off or disengaging the second ink applicator roller group.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide an inking unit for printing machines that is operatable in a variable manner and, in particular, in the short or anilox inking unit mode of operation, and that has ink applicator rollers which can be thrown off a plate cylinder by a throw-off device having a relatively simple construction and being very reliable functionally.
With the foregoing and other objects in view, there is provided, in accordance with the invention, an inking unit in a printing machine, comprising a throw-off device for throwing an ink applicator roller group off a printing form cylinder, the throw-off device including a rotatable roller throw-off cam contoured so that, in a first rotational position of the cam, all the ink applicator rollers are in contact with the form cylinder and, in a second rotational position of the cam, the ink applicator roller group is thrown off the form cylinder and at least one ink applicator roller is in contact with the form cylinder.
In accordance with another feature of the invention, in the second rotational position of the cam, a first ink applicator roller group is thrown off the form cylinder, and a second ink applicator roller group is in contact with the form cylinder.
In accordance with a further feature of the invention, in the second rotational position of the cam, as viewed in a direction of rotation of the cylinder, a first ink applicator roller and a second ink applicator roller are in contact with the form cylinder.
In accordance with an added feature of the invention, in the second rotational position of the cam, as viewed in a direction of rotation of the cylinder, a third ink applicator roller and a fourth ink applicator roller of four ink applicator rollers are in contact with the form cylinder.
In accordance with an additional feature of the invention, in a third rotational position of the cam, all the ink applicator rollers are thrown off the form cylinder.
In accordance with yet another feature of the invention, in a fourth rotational position of the cam, as viewed in a direction of rotation of the cylinder, the first ink applicator roller and the second ink applicator roller are in contact with the form cylinder.
In accordance with yet a further feature of the invention, in the second rotational position of the cam, as viewed in a direction of rotation of the cylinder, the first ink applicator roller is in contact with the form cylinder and the second, and a third and a fourth ink applicator roller are thrown off the form cylinder.
In accordance with yet an added feature of the invention, the inking unit includes two operating cylinders to which pressurized fluid is applicable for rotating the roller throw-off cam into rotational positions of the cam.
In accordance with yet an additional feature of the invention, the operating cylinders are formed as one structural unit having a tandem cylinder.
In accordance with still another feature of the invention, the roller throw-off cam has two guide tracks disposed side by side.
In accordance with still a further feature of the invention, the roller throw-off cam is rotatably mounted coaxially with the form cylinder.
In accordance with still an added feature of the invention, the roller throw-off cam is revolvingly rotatable and driven.
In accordance with still an additional feature of the invention, the roller throw-off cam is contoured approximately as shown in
FIGS. 2
to
5
, on the one hand, and
FIGS. 7
to
13
, on the other hand, respectively.
In accordance with a concomitant aspect of the invention, there is provided a printing machine, especially a rotatable offset printing machine, having at least one inking unit constructed with at least one of the foregoing features.
Thus, the inking unit according to the invention in a printing machine, having a throw-off device for throwing an ink applicator roller group off a form or plate cylinder, is distinguished by the fact that the throw-off device is a rotatable roller throw-off cam that is contoured so that, in a first rotational position of the cam, all the ink applicator rollers are in contact with the form or plate cylinder and, in a second rotational position of the cam, the ink applicator roller group is thrown off the form or plate cylinder, and at least one ink applicator roller is in contact with the form or plate cylinder.
There are offset printing machines in which the inking unit and a dampening unit can be coupled to one another via a connecting roller, and a dampening solution applicator roller applies an ink/dampening solution mixture to the form or plate cylinder when they are coupled. Such a dampening solution applicator roller is not an ink applicator roller in the sense of the invention. Instead, according to the invention, ink applicator rollers are understood to be those applicator rollers which primarily apply printing ink to the form or plate cylinder.
An advantageous feature of the inking unit according to the invention is that the ink applicator rollers are forcibly controlled by the roller throw-off cam, the ink applicator rollers being located in the respectively required position relative to one another, in each of the rotational positions of the cam, and malfunctioning being virtually impossible. A further advantage is to be seen in the low constructional outlay for the inking unit, which has been achieved as a result of the fact that all the ink applicator rollers have a common roller throw-off cam assigned thereto.
When the roller throw-off cam is in the first rotational position of the cam, both the at least one ink applicator roller and the ink applicato
Dorenkamp Felix
Knepper Jens
Eickholt Eugene
Greenberg Laurence A.
Heidelberger Druckmaschinen AG
Locher Ralph E.
Stemer Werner H.
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