Printing – Multicolor – Rotary machines
Reexamination Certificate
2001-01-22
2002-01-15
Eickholt, Eugene (Department: 2854)
Printing
Multicolor
Rotary machines
C101S220000
Reexamination Certificate
active
06338298
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to the integration of cylinders of a rotary printing machine into individual cylinder groups.
BACKGROUND OF THE INVENTION
Prior-art rotary printing machines are driven by a main drive via a mechanical longitudinal shaft, also called a vertical shaft. One disadvantage of these printing machines is the mechanical effort that needs to be taken to compensate the torsion of the longitudinal shaft occurring during operation. As a result, it is necessary to mechanically adjust the circumferential register of print positions of the printing machine during operation.
Attempts have also been made to replace the mechanical longitudinal shaft between the individual printing units with an electrical longitudinal shaft. Thus, each printing unit receives a separate electrical drive. In addition to the high mechanical expense that continues to be necessary because of the complex nature of the individual printing units with a plurality of print positions, there is in this case a high expense for control technique, because synchronous operation of the individually driven printing units with one another must be guaranteed as well.
To avoid the above-mentioned problems, DE 41,38,479 A1 proposes that the cylinders of the printing machine be driven by one electric motor each.
DE 42,14,394 A1 discloses a process control system for such a printing machine with individually driven cylinders. The individual drives of the cylinders and their drive regulators can be arbitrarily integrated into print position groups. The print position groups are associated with folders, from which they obtain their position reference. The process control system proposed consists essentially of a high-speed BUS system for the individual drives and the drive regulators of a print position group and of a higher process control system for managing the print position groups.
Even though the design of the individually driven cylinders pursued in these two documents ensures a high level of flexibility in use, it also requires a very great number of drive motors at the same time, and, as is shown by DE 42,14,394 A1, a very high expense for regulating this great number of individual drives. Moreover, a great variety of motors must be used. If only a few motor sizes were used, it would otherwise frequently be necessary to use oversized motors for different applications. Both drive up the price of such a printing machine.
SUMMARY AND OBJECTS OF THE INVENTION
In contrast to the state of the art, the object of the present invention is to provide a rotary printing machine that can be used in a highly flexible manner and which is yet economical.
According to the present invention, blanket cylinders and plate cylinders of a rotary printing machine form in pairs a cylinder group, in which one blanket cylinder and one plate cylinder are mechanically coupled with one another and are driven together by a separate drive motor per cylinder group.
The number of the necessary drive motors is considerably reduced due to this group integration of the two cylinders and due to their being provided with a single drive for at least one cylinder pair; the number of the necessary drive motors is reduced by at least half compared with the individual drive designs. The mechanical coupling of these two cylinders, which are associated with one another in terms of printing technique, which is preferably a gear coupling with spur-toothed or helical gears, offers considerable advantages in terms of price over the design of the individually driven cylinders. No substantial concessions are to be made in terms of the flexibility of use compared with the individual drive design. Thus, both the circumferential register adjustment and the lateral register adjustment of each blanket cylinder can be performed individually and, if necessary, coordinated with each additional blanket cylinder. Technically and economically optimal print positions can be formed in a rotary printing machine due to the cylinder groups according to the present invention with separate drive motors. The print positions are defined in this connection as the cylinder pairs between which a web of paper to be printed on passes through and is printed on one side or on both sides. Consequently, one cylinder group and a corresponding counterpressure cylinder, which may, but does not have to, belong to the cylinder group, belong to a print position formed according to the present invention. However, the print positions of the printing machine are mechanically independent in terms of the drive technique in both cases, i.e., the print positions of the printing machine are electrically coupled with one another.
The blanket cylinder is preferably driven in the cylinder groups according to the present invention, and the blanket cylinder in turn drives the plate cylinder of the same cylinder group via the mechanical coupling. However, it is also possible to drive the plate cylinder shaft in another embodiment of the present invention, so that the blanket cylinder is driven only via the mechanical drive from the plate cylinder. While the drive of the plate cylinder advantageously requires a small effort for engaging and disengaging the blanket cylinder, the blanket cylinder is, on the other hand, decisive for the positional accuracy and the circumferential register adjustment. The first solution offers the advantage that the cylinder, which ultimately comes directly into contact with a web of paper to be printed on, does not need to be driven via a transmission member that may possibly have a clearance.
It is advantageous to always allow three cylinder groups to work on one print position. One cylinder group is arranged on one printed side, and two cylinder groups are arranged on the opposite printed side of a web of paper passing through between them. The blanket cylinder of the cylinder group arranged on one printed side of the web of paper preferably forms the counterpressure cylinder for the other two blanket cylinders of the cylinder groups arranged on the opposite printed side of the web of paper, and the latter cylinder groups are advantageously both driven alternatingly. This configuration offers the highest flexibility of use for a blanket/blanket production, because the two blanket cylinders that can be used alternatingly during ongoing production can be configured for changing over the print. This is performed by changing the plate of a plate cylinder associated with the non-engaged blanket cylinder. Each cylinder group can be mounted in an individual stand. The two cylinder groups located horizontally opposite one printed side of the web of paper are preferably integrated into a cylinder unit mounted in a stand.
According to the present invention, a cylinder group can be expanded by one counterpressure cylinder for the blanket cylinder. This third cylinder of the cylinder group thus formed is mechanically coupled with the blanket cylinder, preferably by an additional gear coupling. Such a cylinder group already represents a print position, between the blanket cylinder and counterpressure cylinder of which the web of paper to be printed on is passed through. The counterpressure cylinder may be a steel cylinder or another blanket cylinder for two-sided printing. Such a counterpressure cylinder may also especially be a central cylinder of a cylinder unit with, e.g., nine or ten cylinders. In an alternative, equally preferred embodiment of the present invention, such a central cylinder is driven by a separate drive motor. This type of integration guarantees the highest flexibility of use for a cylinder unit. Thus, each of the cylinder groups associated with the central cylinder can be reversed in this case individually and independently from the other cylinder groups, which is necessary, e.g., for alternate printing or for flying plate change.
The individual cylinder group is driven from a drive motor by means of a toothed belt. Such a toothed belt has a high elasticity compared with the solution proposed in DE 41,38,479 A1, according to which th
Koch Dieter
Miescher Andreas
Schneider Felix
Zahnd Andreas
Eickholt Eugene
Maschinenfabrik Wifag
McGlew and Tuttle , P.C.
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