PREVENTING THE FLUTTERING OF THE TAIL IN FILM PRINTING

Abstract

A method and device for carrying out a reel splice to avoid the fluttering of tails makes it possible to allow the tail to also adhere across its entire length, in particular on a web with high mechanical strength. When using a fluid-repelling substrate, an adhesive-free liquid is applied to a new roll and/or to at least a portion of the side of the tail facing the web. The method and device can be used in reel splicers which process fluid-repellent substrates, such as for example plastic films, metal films or laminated laminates, so that a sticking out or fluttering of the tail is avoided.

Claims

1. A method for carrying out a reel splice, comprising: providing a web that runs off an old roll of a substrate to be processed; pressing the web that runs off the old roll against an adhesive point of a new roll; forming an adhesive connection between the web that runs off the old roll and the new roll; severing the web that runs off the old roll at a cutting edge such that at least a portion of a tail with an extension from the adhesive point to the cutting edge remains on the adhesive point; and applying an adhesive-free liquid to the new roll when the substrate to be processed is a fluid-repellent substrate.

2. The method according to claim 1, wherein the adhesive-free liquid comprises water or an aqueous solution.

3. The method according to claim 1, wherein the adhesive-free liquid comprises a hydrocarbon-based liquid.

4. The method according to claim 1, wherein the adhesive-free liquid comprises an emulsion of water or an aqueous solution and a hydrocarbon-based liquid.

5. The method according to claim 1, wherein the adhesive-free liquid is further applied to at least a portion of a surface of a side of the tail facing the web.

6. The method according to claim 1, wherein the adhesive-free liquid is applied when the web is stationary.

7. The method according to claim 1, wherein the adhesive-free liquid is applied when the web is moving.

8. The method according to claim 1, wherein the adhesive-free liquid is applied by a sprayer comprising at least one spray nozzle.

9. The method according to claim 1, wherein the adhesive-free liquid is applied by a strip comprising a liquid-storing border.

10. The method according to claim 1, wherein the tail is pressed against a web that runs off the new roll by a pressing device after applying the adhesive-free liquid.

11. A reel splicer for carrying out a reel splice, the reel splicer comprising an application device configured to carry out a reel splice according to the method of claim 1.

12. A method for carrying out a reel splice, comprising: providing a web that runs off an old roll of a substrate to be processed; pressing the web that runs off the old roll against an adhesive point of a new roll; forming an adhesive connection between the web that runs off the old roll and the new roll; severing the web that runs off the old roll at a cutting edge such that at least a portion of a tail with an extension from the adhesive point to the cutting edge remains on the adhesive point; and applying an adhesive-free liquid to at least a portion of a surface of a side of the tail facing the web when the substrate to be processed is a fluid-repellent substrate.

13. The method according to claim 12, wherein the adhesive-free liquid comprises at least one of an emulsion of water or an aqueous solution and a hydrocarbon-based liquid.

14. The method according to claim 12, wherein the tail is pressed against a web that runs off the new roll by a pressing device after applying the adhesive-free liquid.

15. A reel splicer for carrying out a reel splice, the reel splicer comprising an application device configured to carry out a reel splice according to the method of claim 12.

16. A method for carrying out a reel splice, comprising: providing a web that runs off an old roll of a substrate to be processed; pressing the web that runs off the old roll against an adhesive point of a new roll; forming an adhesive connection between the web that runs off the old roll and the new roll; severing the web that runs off the old roll at a cutting edge such that at least a portion of a tail with an extension from the adhesive point to the cutting edge remains on the adhesive point; and applying an adhesive-free liquid to the new roll and to at least a portion of a surface of a side of the tail facing the web when the substrate to be processed is a fluid-repellent substrate.

17. The method according to claim 16, wherein the adhesive-free liquid comprises at least one of an emulsion of water or an aqueous solution and a hydrocarbon-based liquid.

18. The method according to claim 16, wherein the tail is pressed against a web that runs off the new roll by a pressing device after applying the adhesive-free liquid.

19. A reel splicer for carrying out a reel splice, the reel splicer comprising an application device configured to carry out a reel splice according to the method of claim 16.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0019] Exemplary embodiments of the invention are described in the following detailed description and shown in the accompanying drawing figures, without being limited thereto.

[0020] FIG. 1 shows a schematic illustration of a printing press according to the prior art.

[0021] FIG. 2 shows a schematic illustration of a printing press directly prior to the reel splice according to the prior art.

[0022] FIG. 3 shows a schematic illustration of a printing press directly after a reel splice according to the prior art.

[0023] FIG. 4 shows a schematic illustration of a printing press comprising the reel splicer according to the invention immediately prior to the reel splice.

[0024] FIG. 5 shows a schematic illustration of a printing press comprising the reel splicer according to the invention immediately after the reel splice.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0025] FIG. 1 shows the schematic setup of a web-fed printing press 1, in the case of which the web-shaped substrate is unwound from a rotating old roll 7 in the reel splicer 2. The old roll 7 is supported in non-illustrated clamping mandrels and is either driven in response to the unwinding of the web 5, or is driven and braked, only braked for building up a web tension, or is simply dragged. FIG. 1 shows a schematic sketch of a reel splicer 2, as it is usually used in the case of so-called flying reel splices, but the invention is also possible in the case of so-called shutdown reel splicers or dispensers.

[0026] The unwound web 5 is usually also guided via various web elements, such as deflection rollers 9, the web 5 can thereby alternatively be oriented at right angles to the web running direction 6. It is also possible to bring driven deflection rollers 6 or draw rollers, which are not graphically shown, in contact with the web 5, in order to be able to influence the web tension in the region of the reel splicer 2.

[0027] The web 5, which is unwound from the old roll 7 is fed to the subsequent components of the processing machineafter passing through the remaining part of the reel splicer 2, viewed in the web running direction. In the illustrated example of a web-fed printing press 1, this is usually at least one printing unit, by means of which the web 5 is printed at least on one side, for example in the offset, in the intaglio printing, in the flexographic or in a digital printing method.

[0028] The web 5, which is thus printed at least on one side and at least monochromatically, is fed to a post-processing 4. This can generally be a cross-cutting device or a folding device, for example re-winders are used in the case of the misprinting or processing of films or film-like substrates, such as for example plastic films, metal films or laminates, for example in the packaging printing.

[0029] Due to the fact that the old roll 7 can only have a limited amount of the web-shaped substrate, a new roll 8, which is provided with a double-sided adhesive tape for the preparation of adhesion prior to or after the reel splice, is introduced into the reel splicer 2mostly during the productionto ensure a more or less uninterrupted production.

[0030] The reel splicer 2, which is illustrated in an exemplary manner in FIG. 1, can receive two rolls on its support arm 11, but reel splicers 2 comprising more than two receivable rolls are also known. The number of the rolls as well as the arrangement of the old roll 7, which runs off, as well as of the new roll 8, is irrelevant for the present invention and thus does not represent a limitation.

[0031] FIG. 2 illustrates the web-fed printing press 1 according to FIG. 1, but at a point in time, in which the old roll 7 approaches its minimum diameter. The support arm 11 pivots about a horizontal axis, so that the new roll 8 is brought into a position, in which the adhesion-preparing new roll 8, which is accelerated to the web speed, can be brought into contact with the web 5, which runs off the old roll 7. The so-called splice head 10, which comprises a pressure roller and a cutting knife, is hereby brought into the immediate vicinity of the web 5, which runs off the old roll 7.

[0032] Even if FIG. 2 illustrates the situation directly prior to a reel splice by means of a flying reel splicer 2 or auto-paster, the present invention can also be transferred to other types of reel splicers 2, which are not graphically illustrated, such as for example shutdown reel splicers.

[0033] If the old roll 7 reaches a predetermined diameter for splicing and if the new roll 8 has the circumferential speed, which is exactly identical to the web speed, for example a pressure roll or pressure brush pushes the web 5, which runs off the old roll 7, against the new roll 8, so that the web 5, which runs off the old roll 7, is connected to the web 5 of the new roll 8 by means of an adhesive bond by means of the double-sided adhesive tape, the cutting knife of the splice head 10 severs the web 5, which runs off the old roll 7 immediately after that.

[0034] FIG. 3 shows the web-fed printing press 1 symbolically immediately after the reel splice was made, wherein the web 5 is unwound from the new roll 8 and is fed to the parts of the printing press 1.

[0035] As can be seen in FIG. 3, a tail 12 is created by the severing of the web 5, which runs off the old roll 7, albeit only for a very short time after the web 5 is adhered to the new roll 8, which tail is connected to the web 5 only at the adhesive point 13 and which is thus no longer connected to the web 5 across its extension in the web-running direction 6, which represents the length of the tail 12.

[0036] The tail 12 created in this way, which is actually the remainder of the web 5, which runs off the old roll 7, starting at the adhesive point 13, can thus either hang down due to the force of gravity, so that it can come into contact or comes into contact, respectively, with parts of the printing press 1 due to its length of approx. 20 to approx. 500 mm.

[0037] It is also possible that even though the tail 12 bears on the web 5 in response to higher web speeds or lies on the web 5, provided that the tail 12 is attached to the web top side, the tail 12 can or will stick out from the web 5 either in the case of very stiff substrates or in response to the deflection of the web 5, for example on deflection rollers 9.

[0038] If this tail 12 comes into contact with parts or components of the printing press 1, either portions of the tail 12 can tear off and web shreds can form, which can cause production interferences, or the web 5 can rip or tear completely.

[0039] In particular, in the case of substrates of a high mechanical strength, such as for example plastic films or laminates, it is further possible that parts or components of the printing press 1 are affected as a result of a tail 12, which sticks out.

[0040] Even though devices for detaching such tails 12 are known from the prior art, they fail in response to web speeds, which are not too high, and lose their functionality in particular in the case of substrates with high mechanical strength.

[0041] FIG. 4 shows a printing press 1 comprising a reel splicer 2 for carrying out the method according to the invention. Said reel splicer optionally comprises one or a plurality of application devices 14 for applying adhesive-free liquid to the new roll 8 and/or to the side of the tail 12 facing the web 5.

[0042] In the case of a method for carrying out the reel splice according to the invention, an adhesive-free liquid is applied to the new roll 8 and/or to the side of the tail 12 facing the web 5 at least to or in a partial surface of the tail 12 at the point in time when the web 5, which runs off the old roll 7, which rolls off, of a substrate to be processed, is pressed against the web, which is embodied with the adhesive point 13for example in the form of a substantially double-sided adhesive tape, or, as a function of the web speed, a few seconds to a few hundredth of a second prior to pressing the web 5 against the new roll 8 or to the web 5, which is wound onto the new roll 8, respectively, for forming an adhesive bond between the web 5, which runs off the old roll 7, and the new roll 8 or the web 5, respectively, which is wound onto the new roll 8, and the subsequent severing of the web 5, which runs off the old roll 7, wherein at least one tail 12 with an extension from the adhesive point 13 to the cutting edge on the adhesive spot 13 remains as a result of the severing of the web 5, which is unwound from the old roll 7.

[0043] The film of the adhesive-free liquid, which is preferably applied thinly in this way, wets the surface of the web 5 and/or of the tail 12 resulting therefrom in the case of the use of a substrate, which is fluid-repellent and thus does not absorb the liquid, such as for example plastic films, metal films, laminates with cover layers of fluid-repellent material, such as for example webs (5) laminated with plastic or metal film of non-absorbent or absorbent material or for example impregnated substrates of non-absorbent or generally absorbent material, and can no longer escape when placing the tail 12 to the corresponding web sidein particular after pressing on the tail 12for example by revolving of a deflection roller 9. Due to the capillarity, the liquid is held in the gap, which is thus very thin, between the web 5 and the tail 12 or is also distributed evenly there, respectively, so that a holohedral liquid film remains at least in the regions of the liquid application in particular in response to a spreading or compression of the web 5 in the region of the tail 12, for example after passing through a deflection roller 9 or a roller pair placed against one another.

[0044] Due to the capillary effect and the van-der Waals forces of the used, albeit adhesive-free liquid, the tail 12 thus adheres to the web 5 with a relatively strong adhesion, as long as a liquid film is present. If this liquid film dries or if the liquid diverges out of the substrate or into the substrate, which, however, usually takes longer than the pass-through time of a point through a corresponding printing press 1such a pass-through time is only a few seconds as a function of the press configuration and the web speedthe tail 12 is thus no longer fixed to the web 5.

[0045] FIG. 5 shows the web-fed printing press 1 immediately after the reel splice and the application of the liquid according to the invention to at least a partial surface of the tail 12, so that the tail 12 adheres to the web 5 by means of the van-der Waals forces between the web 5 and the liquid on the one hand and the liquid and the tail 12 on the other hand.

[0046] A tail 12, which is fixed to the web 5 in this way, can be guided with the web 5 through the printing press 1 such that impairments of the production, damages to the web 5 or damages to components or parts of the printing press 1 occur.

[0047] Due to the holding force in the form of the van-der-Waals force of the liquid on the web 5, which is low in contrast to adhesives or adhesive-containing liquids, no impairments whatsoever to the production thus result for example due to web tears, windings or contaminations of web-guiding elements, when the liquid is applied to the web 5 in a region, which is larger than the region, which is covered by the tail 12 located on the web 5.

[0048] If the liquid is for example applied to the web 5 in a region of the extension x, viewed in the web-running direction 6, the liquid is not covered completely by the tail 12. If this region of the web 5 comes into contact with a web-guiding part, such as for example a deflection roller 9 or a printing cylinder, the web-guiding part is wetted with the liquid, but this does not lead to any impairments of the production, such as for example web tears, windings or contaminations with adhesives, which are difficult to remove for the most part, due to the effect of the adhesive-free liquid, which is generally not adhesive.

[0049] The liquid is thus advantageously applied at least across the entire surface of the tail 12. The application can hereby either take place to the adhesive surface or to the web 5, which runs off the new roll 8. It is also possible, however, to apply the liquid in a region, which is spaced apart from the adhesive point 13, i.e. that the application of the liquid is applied only in the rear region of the tail 12, viewed in the web-running direction 6.

[0050] The liquid can also be applied holohedrally or in an interrupted manner in extension across the web width, for example in at least one strip parallel to the web-running direction 6 or in a punctiform manner, that is, also interrupted in the extension of the web-running direction.

[0051] Water or an aqueous solution can be used as liquid. In the case of the aqueous solution, additives are added to the water, for example surfactants, to reduce for example the surface tension of the liquid.

[0052] However, a hydrocarbon-based liquid, such as for example low-viscous oils, oils with average or high viscosity or solvent-like or solvent-containing substances, can also be used as liquid. The wettability is also ensured thereby. Hydrocarbon-based liquids are advantageous in particular when for example printing methods are used, in the case of which water or an aqueous solution on the substrate would lead to an impairment of the printing process.

[0053] An emulsion of water or an aqueous solution and a liquid of hydrocarbon can also be used for application to the web 5 and/or to the tail 12. Such combinations provide for an optimal adaptation of the wettability as well as of the capillarity of the liquid to the substrate and, if necessary, to the processing and/or printing process with regard to the compatibility on the liquid.

[0054] As already specified above, the application of the liquid can take place when the web 5 is stationary as well as when the web 5 moves immediately prior to the reel splice to the web 5, which rolls off the old roll 7 and/or to the web 5, which is wound onto the new roll 8. In the case of the liquid application when the web 5 is stationary, this can either take place in the case of a shutdown reel splicer when the web 5 is stationary inside the reel splicer 2, while the production takes place by removing the web 5 from a paper storage.

[0055] It is also possible, however, which is in particular the case with reel splicers 2, which are designed in a technically simple manner, or dispensers, that the printing press 1 needs to be stopped for re-adhering the web 5 from the old roll 7 to the new roll 8, so that a stationary web 5 already results therefrom, so that the liquid can be applied to the web 5 and/or to the new roll 8 either manually, for example by means of a spray bottle preferably comprising a sprayer, by means of a sponge or a cloth, or by means of an application device 14 within a limited time window prior to the reel splice.

[0056] In the case of highly automated reel splicers 2 with automatic execution of the reel splice, the liquid is applied either to the web 5, which runs off the old roll 7, or to the new roll 8 in response to corresponding web speed, so that an application of the liquidin particular to the new roll 8has to take place immediately prior to the reel splice and is essentially only possible by means of an application device 14, which is installed in the reel splicer 2.

[0057] Such an application device 14 can either be a device, which is embodied with a liquid reservoir, such as for example a liquid-storing border, such as a wetted cloth or a sponge, which is attached to the new roll 8 and/or to the web 5, which runs off, so as to be temporally controlled accordingly. It is also possible, however, to embody the application device 14 as a sprayer comprising at least one spray nozzle, which traverses the substrate in extension of the web or roll width, respectively, or to design it as spray pipe comprising a plurality of nozzles of the at least two outlet openings across the width of the processing web 5. In the case of a spray pipe with extension across the entire web width, the liquid application can thus be temporally controlled very accurately and the position as well as the length of the liquid application can thus be controlled via the clocking of one or a plurality of corresponding valves.

[0058] It goes without saying that such application devices 14 can also be used in shutdown reel splicers or so-called dispensers for the manual re-adhesion of the web 5 from the old roll 7 to the new roll 8, in order to carry out the liquid application in an even, reproducible and automated or partially automated manner.

[0059] Regardless of the type of the liquid application, it is advantageous when the tail 12 is pressed against the web 5, which runs off the new roll 8, by means of a pressing device after the application of the liquid, which can take place for example by means of a deflection roller, a web-guiding roller or draw roller with attached impression cylinder, a draw roller pair attached to one another, or an attached pair of printing cylinders.