DE29622954U1 - Continuous paper for the manufacture of paper products - Google Patents

Description

A 54.024 g Applicant:

13.06.1997 Drescher Business Printing GmbH

p-257 Drescherstrasse

71277 Rutesheim

Continuous paper for the production of paper products

The present invention relates to a continuous paper for the manufacture of paper products, with perforation lines transverse to the longitudinal direction of the continuous paper, along which the continuous paper can be folded, the perforation lines having a pitch that results from the sum of the width of a web and a cut, seen transverse to the longitudinal direction of the continuous paper. The invention also relates to a device for producing continuous paper.

Continuous paper is used in many different ways for the production of various paper products, such as pre-printed forms, mass printed matter, etc. The advantages are that it is easy to handle when using printers that are usually used in the office, as well as in the industrial production of printed products in printing machines, and the possibility of producing extremely large quantities of printed products without the disadvantages that occur when using simple individual papers, such as the necessary adjustment of the paper feed.

Continuous paper has, for example in the header and footer area of each paper product to be made from it, perforation lines transverse to the longitudinal direction of the continuous paper, along which the continuous paper can be folded and separated. It is folded into stacks using Z-folding, whereby Z-folding means the alternating folding of the paper products to be manufactured determined by the perforation lines forwards and backwards.

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This Z-folding allows extremely large stacks of continuous paper to be produced. This also ensures that the continuous paper can be easily fed into a printer, as well as the storage or intermediate storage of the printed or (partially) processed paper.

The perforation lines are usually created by knife strips, the cutting edges of which have teeth and gaps. As a rule, the perforation line created by such a knife strip begins/ends with a more or less wide paper web. The width of the paper web and the cutting length depend on the paper qualities used as well as the printer and paper post-processing specifications. The perforation lines usually begin/end at the edge of the paper web with a cut or paper web. The cut can be converted into a web by filing or sanding the knife strip. However, this method is inaccurate and with unfavorable paper web widths and a specified pitch (to achieve specified tear forces) a certain width of the first web at the beginning/end of the perforation line is often not achievable, even theoretically.

In large-scale production, it was found that if the width of the paper web at the beginning/end of a perforation line is less than approx. 0.3 mm, the paper can tear and thus bend up to the next web of the perforation following the first web. This causes the folding of the paper to result in thickenings in the corners of a stack of such continuous paper, which makes the guiding and filing of this continuous paper considerably more difficult. Automatic post-processing, i.e. subsequent folding, cutting or inserting of the finished paper products, is often no longer possible.

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It is also unavoidable that the paper will buckle if the perforation line created by the knife bar goes just next to or exactly through a guide hole in the continuous paper. This is unavoidable depending on the desired paper specifications as the pin-bearing guide rollers used to transport the continuous paper are standardized. In this case too, automatic post-processing is no longer possible.

However, if the paper web or cut at the beginning/end of the perforation line is wider than approx. 1.4 mm, or if the perforation was not created cleanly by the knife bar, the continuous paper cannot find its ideal fold line required for the Z-fold. The fold can then occur outside the theoretical fold line. Tensions in the paper stack are the result, which leads to slanted stacking.

Finally, if the paper webs at the beginning/end of one or successive perforation lines have an unequal width, and if this width differs from one another by more than 25%, this also leads to the formation of slanted stacks. This creates an unstable, spongy stack that tips sideways at the slightest force. The differing widths of the paper webs at the beginning/end of the perforation lines mean that when the continuous paper is folded, different tensions occur in the paper at these points. In extreme cases, this leads to the continuous paper folding not along the perforation line, but in places just next to it. This is how the slanted stacks mentioned above form.

Furthermore, paper web width fluctuations in the raw paper roll, which are not properly averaged out to both sides of the continuous paper, as well as inaccurate or slow

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working web edge control to form slanted stacks, as this causes the web widths to fluctuate. If the paper moisture is too low when producing the continuous paper from a raw paper roll, the paper width subsequently increases due to the subsequent absorption of moisture. Finally, fluctuating tensile stresses in the printing machine itself can lead to the paper web being offset to the side. Efficient post-processing is then no longer possible.

The formation of the above-mentioned slanted stacks in continuous paper is further promoted by the temperature effect in the printer or printer on such continuous paper webs.

The present invention is based on the object of providing a continuous paper in which the tendency to form slanted stacks is reduced.

This object is achieved according to the invention by the continuous paper mentioned at the beginning in that the pitch in the area of the side edges of the continuous paper is reduced compared to the remaining paper area of the continuous paper.

In the continuous paper according to the invention, each perforation line begins/ends transversely to the longitudinal direction of the continuous paper with a paper web, which itself is perforated, in particular micro-perforated. With this continuous paper according to the invention, even stacks of great height, in particular high stacks with a height of 1 m or more, can be produced without the risk of forming slanted stacks.

Furthermore, due to the exact folding memory of the continuous paper according to the invention, caused by the micro-perforation, even paper of lower quality can be used.

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tat can be processed, which significantly reduces production costs.

When feeding the continuous paper according to the invention to the laser printers that are frequently used today, no difficulties arise with regard to the effects of temperature. This avoids an increased tendency to form slanted stacks.

In addition, the continuous paper according to the invention prevents the paper from folding at that point in the case where a perforation line runs just next to or exactly through a guide hole in the continuous paper, thereby further reducing the tendency to form slanted stacks.

Often, depending on the intended purpose of the continuous paper, it is not only desirable to use single-lane continuous paper, but also two-lane or multi-lane. Such continuous paper consists of two or more parallel webs of continuous paper, which are separated from one another by one or more separating perforations in the longitudinal direction of the continuous paper. The continuous paper webs can be separated along these separating perforations.

It is particularly preferred in such a continuous paper which has one or more separating perforations in the longitudinal direction that the pitch of the perforation lines transverse to the longitudinal direction of the continuous paper is reduced in the area of the separating perforation lines and in particular corresponds to that in the area of the side edges of the continuous paper.

Furthermore, the continuous paper according to the invention has a pitch that extends in the area of the side edges of the continuous paper over a length of the perforation line of approximately 1.5 mm to

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approx. 20 mm. This advantageously ensures that the forces acting over the entire length of the perforation line during folding are approximately the same. The reduced pitch preferably corresponds to the pitch of a micro-perforation.

The continuous paper can be produced by creating perforation lines transverse to the longitudinal direction of the continuous paper in a cut with a knife bar, in which the pitch of the knife bar in the area of the side edges of the continuous paper is reduced compared to the pitch in the remaining paper area of the continuous paper.

The stacks of continuous paper produced in this way are aligned exactly along the perforation lines and spring back when a force is applied from the side. This prevents the formation of slanted stacks and ensures particular stability even when stacked high.

The invention further relates to a device for producing continuous paper with a knife bar for producing perforation lines transverse to the longitudinal direction of the continuous paper, wherein the knife bar has teeth and gaps arranged between them and a pitch which results from the sum of the width of a tooth and a gap in the longitudinal direction of the knife bar, in which the pitch of the knife bar in the area of the side edges of the continuous paper is reduced compared to the pitch in the remaining paper area of the continuous paper.

The perforation lines produced with such a device have a paper web with a perforation, especially a micro-perforation, at their beginning/end. If the first, very narrow web of such a micro-perforation tears,

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only minimal buckling occurs up to the next narrow web of paper. As a result, the perforation lines produced with the device according to the invention advantageously have a predominantly equal length. Paper stacks with perforation lines produced by the device according to the invention do not have any measurable thickening at the corners of the stack.

Furthermore, changes in the paper width or in the path of the raw paper roll do not have a negative effect, since the reduced pitch in the area of the side edges of the continuous paper means that no disadvantageous over-wide web or cut can occur, which causes the quality losses already described. Along a perforation line created with the device according to the invention, the continuous paper folds advantageously up to the edge of the paper web, exactly in the theoretical fold line.

Preferably, when using continuous paper with one or more separating perforation lines in the longitudinal direction of the continuous paper, the knife bar of the device according to the invention has a reduced pitch in the area of these separating perforation lines, which in particular corresponds to that in the area of the side edges. This makes it possible in particular to deposit, print or send the described continuous paper separately, both in its entirety and after separation along the separating perforations running in the longitudinal direction of the continuous paper, to post-process it.

In particular, the knife bar of the device has a pitch of approx. 0.2 mm to approx. 2.5 mm in the area of the side edges of the continuous paper. The teeth of the knife bar preferably have a width of approx. 0.1 mm to approx. 1.5 mm, preferably from approx. 0.45 mm to approx. 1 mm. Accordingly,

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the gaps in the knife strip have a width of approx. 0.1 mm to approx. 1 mm, preferably from approx. 0.25 mm to approx. 1 mm. The pitch in the remaining paper area of the continuous paper has a known and commonly used value that corresponds to given specifications. However, for paper qualities that are difficult to fold, it can be advantageous to weaken the webs of the perforation lines not only in the area of the side edges, but at regular intervals along the entire perforation line by applying micro-perforations, thus further improving the folding memory of the continuous paper. The reduced pitch of the knife strip of the device preferably corresponds to that of a micro-perforation.

Furthermore, the knife strip of the device preferably has a length greater than the width of the continuous paper used, wherein the pitch in the area of the knife strip which lies outside the continuous paper used corresponds to the reduced pitch in the area of the side edges of the continuous paper. This advantageously further minimizes the harmful effects of any irregularities in the path of the web or due to a different width of the raw paper roll.

These and other advantages of the invention are explained in more detail with reference to the following drawings. These show in detail:

Fig.l is a plan view of a knife strip according to the invention;

Fig.2 is a plan view of another embodiment of the knife strip according to the invention;

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Fig.3 is a plan view of the edge area of a continuous paper according to the invention.

Fig. 1 shows a knife strip according to the invention, designated overall by the reference number 10, which has teeth 12 and gaps 14 arranged between them. A pitch dimension 16 results from the sum of the width of a tooth 12 and the width of a gap 14 of the knife strip 10, each seen in its longitudinal direction. The pitch dimension 16 of the knife strip 10 in the area of the side edges of the continuous paper is reduced compared to a pitch dimension 18 in the remaining paper area of the continuous paper.

The pitch dimension 16 of the knife strip 10 in the exemplary embodiment is 0.7 mm, with the teeth 12 having a width of 0.45 mm and the gaps 14 having a width of 0.25 mm in the longitudinal direction of the knife strip 10. The pitch dimension 18 in the remaining paper area of the continuous paper is 5 mm, with the width of a tooth being 4 mm and the width of a gap being 1 mm, each in the longitudinal direction of the knife strip 10. A height 20 of the teeth 12 is 0.6 mm.

When using a raw paper roll with a paper width of 240 mm, the total length of the knife strip 10 is preferably 250 mm. The known and commonly used pitch dimension 18 in this case extends over an area of 231 mm of the knife strip 10. The pitch dimension 16, which is reduced compared to this pitch dimension, extends in the area of the side edges of the continuous paper over a length of approximately 9.5 mm each. The areas of the knife strip 10 with the pitch dimension 16, which extend beyond the width of the raw paper roll used, reduce the disadvantageous effects that can occur due to fluctuations in the paper web width of the raw paper roll or due to inaccurate or sluggish web edges.

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The height of the teeth also affects the stack formation.

Fig.2 shows a further embodiment of the invention in the form of a knife strip 30, which has a reduced pitch 36 corresponding to the area of the side edges of the continuous paper additionally arranged centrally on the knife strip 30. Such a knife strip is used for producing perforation lines on continuous paper with a separating perforation in the longitudinal direction of the latter, wherein in an area corresponding to this separating perforation of the continuous paper the pitch 36 of the knife strip 30 is reduced compared to a pitch 38 in the remaining paper area of the continuous paper.

When using a raw paper roll with a width of 750 mm, the pitch dimension 36 of the knife strip 30 extends in the area of the side edges and in the area of the separation perforation of the continuous paper over a length of approximately 15 mm each, the pitch dimension 38 in the remaining paper area of the continuous paper extends over a length of the knife strip 30 of 360 mm each.

The pitch dimension 36 in the area of the side edges of the continuous paper and in the area of the separating perforation is 2 mm, with teeth 32 having a width of 1 mm and gaps 34 also having a width of 1 mm in the longitudinal direction of the knife strip. The pitch dimension 38 in the remaining paper area of the continuous paper is 4 mm, with the teeth 32 having a width of 3 mm and the gaps 34 having a width of 1 mm in the longitudinal direction of the knife strip. A height 40 of the teeth 32 is 2 mm.

The blade strips 10 in Fig. 1 and 30 in Fig. 2 have a tooth 22 or 32 at their beginning/end, but instead of the

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Tooth 22 or 42 also has a gap 24 or 44 at the beginning/end of the knife strip 10.

The knife strips 10 and 30 can be made from a variety of materials, but hardened tool steel, ground and polished, is preferred.

With the knife strips 10 and 30 it is possible to perforate paper and other printing materials with different grammages, whereby such a perforation is very easy to tear off. The stacks or high stacks of continuous paper with Z-folding produced with the knife strips 10 and 30 according to the invention are precise and stable and spring back when lateral force is applied. With the knife strips 10 and 30 according to the invention, continuous paper can also be perforated from the roll first and then rolled up again. The folding along the perforation lines from the roll into the stack then takes place subsequently. With such a perforation, the continuous paper finds its exact turning point according to its folding memory. Unstable and spongy stacks are avoided, which results in extremely good storage behavior. During the separation process, the perforation tears precisely due to the reduced division in the area of the side edges of the continuous paper. Uncontrolled separation processes are avoided.

Figure 3 shows a top view of the edge area of a continuous paper 50 according to the invention, including perforation lines 52, 53 and guide holes 54, 55, whereby the continuous paper 50 has an exemplary paper specification. While the perforation lines 52 are located centrally between the guide holes 54, the perforation lines 53 run just next to the guide holes 55 of the continuous paper 50. This is unavoidable due to the standardization of the pin-bearing guide rollers for the continuous paper 50 for certain given paper specifications.

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By reducing the pitch 56, an unfavorable cutting or tearing of the continuous paper 50 along the perforation lines 53, which run just next to the guide holes 55, can be avoided, thereby further reducing the tendency to form slanted stacks. This also applies in the case in which the perforation lines run exactly through a guide hole in the continuous paper.

Claims (10)

A 54.024 g - 13 - 13.06.1997 Claims 1. Continuous paper for the manufacture of paper products with perforation lines transverse to the longitudinal direction of the continuous paper, along which the continuous paper can be folded, whereby the perforation lines have a pitch which results from the sum of the width of a web and a cut, seen transverse to the longitudinal direction of the continuous paper, characterized in that the pitch in the area of the side edges of the continuous paper is reduced compared to the remaining paper area of the continuous paper. 2. Continuous paper according to claim 1, characterized in that it has one or more separating perforation lines in the longitudinal direction, wherein the pitch of the perforation lines in the region of the separating perforations is also reduced. 3. Continuous paper according to claim 1 or 2, characterized in that the reduced pitch of the continuous paper extends over a length of the perforation line of approximately 1.5 mm to approximately 20 mm. 4. Continuous paper according to one of the preceding claims, characterized in that the reduced pitch corresponds to the pitch of a micro-perforation. 5. Device for producing continuous paper according to one of claims 1 to 4 with a knife bar for producing perforation lines transverse to the longitudinal direction of the continuous paper, the knife bar having teeth and between these α 54.024 g - 14 - 13.06.1997 arranged gaps and a pitch which results from the width of a tooth and a gap in the longitudinal direction of the knife strip, characterized in that the pitch of the knife strip in the area of the side edges of the continuous paper is reduced compared to the pitch in the remaining paper area of the continuous paper. 6. Device according to claim 5, characterized in that when using continuous paper with one or more separation perforation lines in the longitudinal direction of the continuous paper, the knife bar in the area of these separation perforation lines has a reduced pitch. 7. Device according to claim 5 or 6, characterized in that the reduced pitch of the knife strip is approximately 0.2 mm to approximately 2.5 mm. 8. Device according to one of claims 5 to 7, characterized in that the teeth of the knife strip have a width of approximately 0.1 mm to approximately 1.5 mm. 9. Device according to one of claims 5 to 8, characterized in that the reduced pitch of the knife strip corresponds to the pitch of a micro-perforation. 10. Device according to one of claims 5 to 9, characterized in that the knife strip has a length greater than the width of the continuous paper used and that the pitch in the area of the knife strip which lies outside the continuous paper used corresponds to the reduced pitch in the area of the side edges of the continuous paper.