Printing – Rolling contact machines – Rotary
Patent
1986-05-27
1988-02-02
Fisher, J. Reed
Printing
Rolling contact machines
Rotary
101181, B41F 506, B65H 2314, B65H 23188
Patent
active
047222751
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for controlling the tension of a running print sheet or web for use with a rotary press.
2. Description of the Related Art
A typical monochromatic perfecting unit and of a typical monochromatic perfecting and multicolor oneside printing unit for use with a conventional rotary press are shown in FIG. 1 and FIG. 2, respectively. According to the monochromatic perfecting unit as shown in FIG. 1, a running printing sheet or web of paper 1 is, after having been printed by the monochromatic perfecting unit 2, directed through a guide roller 3 toward a midway drag roller 4, whereby the web of paper is subjected to traction to be delivered to following operations.
According to the monochromatic perfecting unit and the multicolor one side printing unit as typically shown in FIG. 2, the running web 1 is, after having been printed by the monochromatic perfecting unit 2, directed through a guide roller 5 toward a midway drag roller 4, whereby the web is subjected to traction to be delivered to a multicolor one side printing unit 5, where the web is subjected to the multicolor printing operations and is then redirected to following procedures in the printing line.
In the construction of the rotary press as schematically shown in FIGS. 1 and 2, it is observed that there occurs a substantial variation in tension of the running web 1 extending in the upstream and downstream of the monochromatic perfecting unit 2 and the multicolor one-side printing unit 5. This variation in tension of the web is considered to result from the possible loss of tension by way of the slots of the printing cylinder and of vibrations occurring per one operating cycle of the printing cylinder, and such variations in tension result in such faults such as deviations in the cutting of the printings and such as offset doubles, or the like.
SUMMARY OF THE INVENTION
In consideration of such problems as noted above, it is an object of the present invention to provide a tension control apparatus for use with a rotary press which can prevent the faults in the conventional printing units such as the occurrence of offset doubles and the deviation in the cutting of the printings, by eliminating possible variations in the tension of a running printing sheet or web upstream and downstream of the printing units incorporated in the rotary press line.
According to the invention, there is provided a tension control apparatus for use with a rotary press, which comprises, as briefly summarized, a midway drag biasing roller adapted to be urged resiliently against the outer circumferential surface of a midway drag roller, a biasing device adapted to resiliently apply an urging pressure upon the midway drag biasing roller so that it may be urged properly in the biasing direction, a tension detecting device adapted to detect the tensions of the printing sheet or web extending upstream and downstream of a printing unit, and a control device adapted to control the urging force of the biasing device in accordance with due signals from the tension detecting device, so that the tensions of the running web upstream and downstream of the printing unit may be equalized, whereby there is attained such advantageous effects such as preventing a loss of tension in the printing web as would be encountered in the area of the slotted section of a printing cylinder, and such as reducing possible variations in the tension of the running web, thus resulting in the efficient prevention of defects such as offset doubles and variations in the cutting of the printings.
The present invention will now be described by way of preferred embodiments thereof taken with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 2 are schematic views show portions of conventional printing units;
FIG. 3 is a schematic view showing the system of a tension control apparatus by way of a preferred embodiment of the present invention for use with a rotary press;
FIG. 4 is a
REFERENCES:
patent: 3098432 (1963-07-01), Bechtold et al.
patent: 4004510 (1977-01-01), Roch
patent: 4096801 (1978-06-01), Martin
Nippon Shinbun Kyokai Komu Iinkai-hen, "Shinbun Insatsu, Insatsu-hen Kaitei ban" Oct. 31, 1980, Shadan Hojin Nippon Shinbun Kyokai, pp. 214-215, FIG. 57, p. 281, FIG. 46.
Matsuoka Hitoshi
Taguchi Toshio
Fisher J. Reed
Mitsubishi Jukogyo Kabushiki Kaisha
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