Process and apparatus for perforating, stamping or creasing of p

Manufacturing container or tube from paper; or other manufacturi – With printing or photographic reproduction – And cutting – breaking – tearing – or abrading

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Details

83347, 101226, 101DIG19, B41F 1356

Patent

active

045965463

DESCRIPTION:

BRIEF SUMMARY
SUMMARY OF THE INVENTION

The invention relates to a process for perforating, stamping or creasing of paper and cardboard in rotary printing presses by means of strips prepared in advance and arranged on a base sheet, the strips being placed on the base sheet before the beginning of the work cycle, outside the machine; as well as an apparatus for carrying out this process.


BACKGROUND OF THE INVENTION

An apparatus for carrying out stampings and perforations on printed or unprinted papers on rotary printing presses is known from U.S. Pat. No. 3,554,070. In this known device, the tools consist of angled strips with one long and one short leg. The short leg runs at right angles to the long leg and is designed as a cutting edge. Depending on the effect desired, the cutting edge is designed to be either continuous or interrupted. For perforating, for example, it is saw-tooth-like in form. The strips are provided with glue on the under surface of the long leg and are glued into position directly on the impression cylinder of known rotary printing presses. This impression cylinder is in contact, in the known way, with the blanket cylinder, which in turn is in contact with the plate cylinder. After the strips are arranged in the desired position on the impression cylinder, the paper to be processed is conducted between the impression and the blanket cylinders, and the cutting edges of the strips perforate the paper at the desired places. At the same time, a printed image may be transferred to the paper from the plate cylinder via the blanket stretched on the blanket cylinder.
In practice it has been found that a simultaneous printing and perforation or stamping of the paper is only possible at the cost of considerable lowering of quality of the printed product. The cutting edges of the strip, striking through the paper, damage the rubber blanket on the blanket cylinder and leave cuts in the rubber blanket surface. Thus, the rubber blanket can no longer be used for further printing runs and must be replaced. Moreover, the gluing of the strip-form tools to the impression cylinder is also time-consuming and costly. In the case of perfecting presses with roughened impression cylinders, the tools cannot be glued on, since they will not hold to the surface of the impression cylinder or will smear the freshly printed sheet. A further disadvantage found is that the leg of the strip bearing the cutting edge can only have a maximum height which corresponds to the distance between the surface of the impression cylinder and the surface of the rubber blanket on the blanket cylinder. Since in this space the support leg of the tool must also fit, the cutting edges do not extend over the whole height of the short leg, and the paper may either not be completely cut through, or raised places as well as tool marks are formed on the paper. As a result of the former, the paper parts cannot be perfectly separated from each other, and as a result of the latter, no high stacks of finished sheets of paper can be formed.
According to Swiss Pat. No. 587,107, the idea is known, in rotary stamping or die-cutting presses, of placing the cutting strip on a sheet by means of a binder, and then mounting this sheet on the stamping cylinder. The use of this process in rotary printing presses involves additional disadvantages, since the sheet mounted on the impression cylinder reduces the space between the impression cylinder and blanket cylinder, necessary to allow the paper to run through. In some types of machine, the placement of a sheet provided with strips on the impression cylinder is only possible with very great difficulty.
The present invention attacks the problem of avoiding the disadvantages of the known technology and providing a solution by which perforation, stamping or creasing of paper or cardboard on rotary printing presses can be carried out perfectly, without parts of the press or of the printing equipment being damaged. The solution should also make possible a shortened downtime of the rotary printing press and permit high wor

REFERENCES:
patent: 1618191 (1927-02-01), Hemberger
patent: 1668258 (1928-05-01), Adsit
patent: 2842202 (1958-07-01), Boyd
patent: 3147658 (1964-08-01), Boyd
patent: 3250152 (1966-05-01), Kirby et al.
patent: 3355969 (1967-12-01), Sarka
patent: 3431847 (1969-03-01), Smith et al.
patent: 3554070 (1971-01-01), Boyd
patent: 3564942 (1971-02-01), Wolfe

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