Printing – Multicolor – Rotary machines
Reexamination Certificate
2000-05-17
2001-04-24
Asher, Kimberly (Department: 2854)
Printing
Multicolor
Rotary machines
C101S177000, C101S183000, C101S217000
Reexamination Certificate
active
06220156
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a multicolor printing unit for a sheet-fed rotary printing press. The press has an access or servicing side and a drive side. A single counter-pressure cylinder, that carries a plurality of gripper systems, cooperates with at least four printing groves.
DESCRIPTION OF THE PRIOR ART
Printing devices, generally as described above have become known, for example from U.S. Pat. No. 4,098,185. Several printing cylinders, with their ink units have been arranged in a semicircular shape around a rubber blanket cylinder. The rubber blanket cylinder has a diameter which is several times the diameter of the printing cylinder. A counter-pressure cylinder, with a controllable row of grippers, acts together with the rubber blanket cylinder. The counter-pressure cylinder has a single diameter, i.e. the same diameter as the printing cylinders.
U.S. Pat. No. 3,041,966 discloses a multicolor printing unit for a web-fed rotary printing press, having a central counter-pressure cylinder and five printing groups. The printing groups with ink feeds, ink application rollers, printing cylinders and rubber blanket cylinders are not accessible from a service space which is easily accessible from the direction of a press side, i.e. from either the service or drive side of the press. Instead, it is required to first move all of the ink units away together in order to access a service space for the printing cylinder, rubber blanket cylinder and ink unit cylinders.
A service space for the four inking groups of a multicolor printing unit in accordance with DE 195 03 619 A1 is not accessible from the direction of a press side, i.e. from either the service or drive side of the printing press. Instead the service space, is only accessible from the feeding side, the delivery side, or from above.
SUMMARY OF THE INVENTION
The object of the present invention is based on providing a multicolor printing unit for printing sheet-like print carriers made of paper, for example.
This object is attained by means of the provision of a multi-color printing unit having a servicing side and a drive side. A single counter-pressure cylinder carries a plurality of sheet gripper systems and cooperates with at least four printing groups. A number of these printing groups are combined into dual printing groups having free access. Directly adjacent dual printing groups are arranged at an acute angle whose vertex points toward the counter-pressure cylinder.
The advantages which can be achieved with the multicolor sheet-fed rotary printing unit in accordance with the present invention will be briefly described in what follows. It is possible to manufacture a multicolor sheet-fed rotary printing press of the most compact construction. Nevertheless, good accessibility to the ink duct, screen roller, ink application roller, printing cylinder and rubber blanket cylinder is assured. Even with sheet-fed rotary printing presses for small formats, for example DIN A4, sufficient space remains for easily servicing the press and to arrange image devices for the print forme such as plate or foil or the print cylinder itself. Four-color printing of the sheets takes place in a single gripper operation. A perfect color registration becomes possible by means of this. No continuous raising and re-application of ink application rollers is required during the printing process. So-called slit fastenings, clamped fastenings, as well as sleeves, can be used for fastening the covers of the ink application rollers, the print formes and the rubber blankets. The use of sleeves is also possible in connection with screen rollers. In an advantageous manner, no dampening unit is provided. It is therefore possible to employ ink for “waterless” offset printing, UV inks, and also inks, wherein the dampening fluid, or a substitute for the dampening fluid which is worked into the ink itself or is chemically bonded with it, are already contained in the ink prior to filling the ink duct with it. It is also possible to use inks, wherein the dampening fluid or its substitute are supplied to the ink in the ink duct. So-called “hot melt” ink can also be employed.
The dual printing groups can be combined in a simple way from two individual printing groups.
REFERENCES:
patent: 3041966 (1962-07-01), Polglase, Jr.
patent: 4098185 (1978-07-01), Davidson, Jr.
patent: 4854231 (1989-08-01), Jahn
patent: 4936211 (1990-06-01), Pensavecchia et al.
patent: 5469787 (1995-11-01), Turner et al.
patent: 19503619 A1 (1995-02-01), None
Asher Kimberly
Jones Tullar & Cooper PC
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