Printing – Multicolor – Rotary machines
Patent
1998-06-04
1999-09-07
Fisher, J. Reed
Printing
Multicolor
Rotary machines
B41F 506, B41F 508, B41F 13004
Patent
active
059470232
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a rotary printing press.
BACKGROUND INFORMATION
A newspaper offset rotary printing press, referred to hereinafter as a rotary printing press, usually includes a plurality of producing units, called rotations, which can operate simultaneously and independently of one another (maximum 10). Each producing unit includes of reel stands for the paper rolls, draw rollers for feed and delivery of the paper web at the printing towers, printing stations which are combined as U printing groups (two printing stations), Y printing groups (three printing stations) or H printing groups (four printing stations) in one or more printing towers, auxiliary drives on the printing stations (e.g., for changing plates) and the folding unit.
A rotation is usually controlled by a plurality of programmable controller systems, which are in turn guided by higher-level control centers. To permit efficient data exchange, the systems are networked over serial bus systems.
A printing station includes a rubber cylinder, a plate cylinder and an inking and dampening unit. One ink color can be printed on one side with each printing station. A rotation includes all the printing stations which operate on one folding unit, i.e., all their printed paper webs are sent to one folding unit. The printing stations in a machine are accommodated in printing towers, a maximum of eight printing stations in one tower (eight-station tower). In the future, ten printing stations in one tower (ten-station tower) will be the goal. In one rotation, a maximum of twelve eight-station towers can work with one folding unit.
FIG. 1 shows a conventional rotary printing press with shafts. One, or in many cases even two mechanical longitudinal shafts 2 linked by gears 4 (e.g., conical gears) and mechanical vertical shafts 6 in printing towers 8, 10, 12 permit, due to rigid coupling, angular synchronization of all printing stations 14 with one another and with a folding unit 16 or 18 within one rotation. Synchronization is always necessary only within one rotation. Longitudinal shaft 2 runs through the entire machine and is usually driven by a plurality of main motors--for reasons pertaining to flexibility and torque distribution. Coupling and uncoupling of vertical shafts 6 and printing groups 20 take place by means of mechanical couplings 22. Furthermore, additional separating couplings 24 must be incorporated into longitudinal shaft 2 if individual printing towers 8 and/or 10 and/or 12 are to work in different rotations. By opening longitudinal shaft coupling 26 between printing tower 8 and printing tower 10, two rotations can operate independently of one another--printing tower 8 with folding unit 16 and printing towers 10 and 12 with folding unit 18.
The flexible allocation of printing stations 14 to a plurality of folding units 16 and 18 is determined exclusively by the mechanics. Any increase in flexibility must come at the price of an increased expense in terms of mechanical components (higher cost of acquisition of the machine).
Disadvantages of the conventional drive design with mechanical shafts include: manufacturing tolerances of the mechanical components, e.g., .+-.50 .mu.m in the print in newspaper rotations,
For more than 30 years, there have been repeated attempts in the area of printing press development to replace the synchronization of the drive components by means of mechanical shafts with a synchro. This is done in conjunction with replacement of the d.c. technology with three-phase technology. In the 1960s and 1970s, several attempts were made in the development departments of printing press manufacturers Wifag, MAN Roland, in collaboration with electronics companies to introduce a drive technology without longitudinal shafts for gravure printing presses. However, this has not gone beyond the experimental stage in gravure printing technology. This research was not resumed until the beginning of the 1990s, this time in the area of rotary offset machines for newsprint. Hamada Printing Press
REFERENCES:
patent: 3557692 (1971-01-01), Lee
B. Fuchs, "Dem langswellenlosen Maschinenantrieb gingen viele Versuche voraus", Print 39, 1994.
Bohrer Wolfgang
Moller-Nehring Walter
Schroder Heiko
Zimmermann Horst
Fisher J. Reed
Siemens Aktiengesellschaft
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