DE102011118609B4 - Apparatus and method for the production of printed web-shaped materials - Google Patents

Abstract

Device in a film blowing system, on a cast extrusion system, on a rolling mill for metal foils or on a manufacturing system for textile materials, whereby a film, metal or textile web is printed directly with a print image directly through color nozzles as soon as one is produced has formed a suitable surface without prior interim storage or removal of the film, metal or textile web, so that within one and the same system, without spatial and temporal interruption, both the production of the film, metal or textile web from one Raw or semi-finished material as well as the printing.

Description

Plastic films, according to the prior art z. B. for packaging purposes initially produced as a carrier material and printed in a later, separate step or further refined.

For this purpose, the plastic film web initially unrolled unrolled, transported and stored. For later printing, it is then unrolled again and passed through a printing press where printing takes place. Optionally, before the printing and the cutting of the web in single sheets, which are then further refined.

When printing on plastic films, a pre-treatment of the surface is required in many cases in order to improve the ink adhesion during printing. This surface treatment can, for. B. by corona discharge, flaming or chemical pretreatment. With inline printing, this pre-treatment can be omitted.

An inline printing of material webs is known for example from the production of composite films for beverage composite cartons. In this case, however, the printing (for example in gravure printing) takes place on the already finished material web, which as a rule is also temporarily stored. At least one component of the material web is prefabricated, d. H. For example, a finished board web is coated with polyethylene and later printed. The application of the printed image is thus not in connection with the formation of the web as such.

In the patent DE 600 09 213 T2 a method and a device for direct printing of a paper web for baking papers are described. Apart from the fact that reference is made exclusively to materials produced from fibers by means of a paper machine, this invention can not be transferred to the production and finishing of plastic films. While the imprinting taking place immediately after forming is a considerable advantage in the case of the latter because of the surface structures which are then still present, this is, for example, a considerable advantage. As in a fresh paper web a particular disadvantage, since it must be dried only to a certain moisture content. Even otherwise, both the material basis and technology in paper machines are completely different than in the production of plastic films, for example by the blown film process. While a film tube is extruded and compressed by compressed air, stretched and collapsed after the solidification by cooling and rolled up, the paper is made by dewatering and subsequent drying of a fiber suspension on a sieve or between sieves. Also, the requirement of the three-dimensional arrangement of the printheads, z. B. inline printing on a blown film, represents a completely different technology.

In another application EP 1 816 257 A1 is also referred exclusively and explicitly to paper-like materials produced from aqueous suspension fibers, but not to plastics. The disadvantages and not given transferability to film webs apply here accordingly.

In the patent CH 649 573 A5 Although the finishing of a plastic surface is described, but this is done according to the invention only with a specially developed transfer printing process using a carrier paper. Moreover, it is not about general film products such as packaging and decorative films, but explicitly about special Skibeläge. The applied printing has no decorative or information-storing tasks but according to the invention should be invisible or read only by machine and only serve to control subsequent processing machines. In addition, before the transmission of the pressure marks a renewed, significant heating of the film take place, which also does not correspond to the invention presented here.

The patent also deals with the dyeing or printing explicitly of roller-extruded skiboots WO 81/03462 A1 which, however, is essentially based on the principle of sublimation. According to the invention, the surface to be printed must be specially heated and brought into a thermoplastic melt state. In addition, a color carrier is required for the color transfer, which is to be understood as a solid printing form, and must be in direct contact with the surface to be printed. In addition, the printing takes place only along a narrow surface strip transverse to the conveying direction.

In a fifth application DE 10 2009 058 803 A1 Finally, it is about the technical printing of counterfeiting security features on card bodies made of plastic, here also no decorative tasks are to be solved and a machine readability or difficult imitation represent the aim of the invention. The claims relate exclusively to card body or portable data carriers, so also not on films for packaging or decoration purposes, and this is not about the production or production and refinement of the films themselves. The patent also relates exclusively to multilayer plastic body, wherein the individual layers must have different properties. Without this multilayer structure, the method described there is not effective.

Furthermore, methods for coating strip-like materials are known, for example the dip coating of metal strips. In this case, however, no attachment of a differentiated print image is possible.

Likewise, the printing flat plastic films, textile or metal foil webs by means of conventional, z. B. offset printing, or digital, z. As inkjet printing, printing process known. For example, packaging films are printed in gravure or flexo printing, while textiles or posters are screen printed or inkjet printed. However, all these methods have in common that the production of the material web and its printing are always separate, independent production processes with clear spatial and temporal separation and intermediate storage. In particular, in this case the manufacturing process of the film material to be printed on, as a separate process already completely or at least largely completed.

In addition, it is known that material webs - especially for processing and quality assurance purposes - can be provided with individual markings during their production. However, the marking systems used for this purpose are not suitable for mounting complex, z. B. decorative prints.

The object of the invention is to simplify the printing of foil, metal and textile surfaces to the effect that it already takes place directly in the production process of the material web, so that a later handling, for. B. a renewed unwinding and rolling up the web for the purpose of printing can be omitted.

The object is achieved by a device having the features of claim 1 and the features of the independent method claims 4-6. It is provided that the printing of the plastic film or textile or metal foil web is already integrated in their manufacturing process so that no intermediate storage or removal of the web are required. The web feed resulting from the production process of the web should not be significantly impaired or changed. For this purpose, at a suitable point in the process of production printing devices must be attached, which apply the desired printed image on the web. If necessary, the information to be printed has to be converted to the web surface which is not lying flat so that the desired result is achieved after the end of the production process. This can be done by using suitable measuring technology and control software. Especially in modern digital printing processes, the continuous adaptation of printed images to changing conditions such. B. Location and dimensions is not a problem.

In addition to saving the additional, usually offline taking place printing process can, for. B. in the film production on the pretreatment of the film surface to improve the ink acceptance (eg., By flame treatment, corona discharge or chemical treatment) are omitted, because this is not yet required in freshly prepared films due to the not yet completely completed surface training. This gives a further significant saving.

Since the production of plastic films, textile or metal webs is usually slower than their subsequent printing, the conditions for printing are ideal because so despite the simultaneous time savings by eliminating the separate printing process, a lower printing speed is possible, which benefits the print quality comes.

embodiments

In a first embodiment, an annular printhead, the z. B. may consist of an array of inkjet heads mounted ( 1 ). The resulting film in the blower exits from the ring die and passes through the ring-shaped print head, where the printing takes place immediately. The film web is tubular at this time, by the overpressure of the blowing air inside the film tube this is kept smooth and stable on the surface, so that a defined printing is possible. Any deviations from the diameter and position of the film tube can be detected by suitable measuring optics and compensated by converting the printed image to be applied. In digital printing, which includes the inkjet process, the information to be printed can be changed in real time, making this adaptation possible. In this way, deviations can also be detected by a subsequent stretching of the film tube, twists of the film tube during cooling, flattening and rolling as well as possible speed differences in the production process of the films and compensated for by appropriate print image adjustments. By analogy with this, it is also possible to use metal or textile webs as soon as they have developed to such an extent that their final dimension has essentially been reached.

The relatively low web speed of the films is very conducive to a comfortable design of the printing process and can be synchronized well with the technically feasible printing speeds of the inkjet heads. If necessary, several, successively arranged printheads can be mounted, whereby z. B. higher printing speeds or better image resolution can be achieved.

Due to the production of the film web, which takes place directly before printing, a prior surface treatment of the film is not necessary since the ink acceptance is initially very good. As a result, it is also possible to reduce problematic, highly solvent-based ink systems and complex dryers.

Because the film web after production and printing for cooling is still performed over a distance free as a film tube, excellent conditions are also given for drying the ink. Here, if necessary, devices for quality control of the printed image can be provided.

Due to the digital printing process used, different print designs can be produced immediately following each other and without interrupting the film production process. It is also conceivable mixing of various printed images, z. B. in the longitudinal direction of the films, strip-shaped side by side.

For distinguishing individual print motifs and for detecting the position of the web, the z. B. is required for the subsequent division of the film web, corresponding marks on the edge of the film or other suitable location can already be applied in the printing process, which can be read when flattening, rolling up and dividing the film web and used to control the respective working device. A later, separate printing is no longer required, so that the film can be used immediately after leaving the plant.

In a further embodiment, the printheads are not annular but arranged in any arrangement about the film web, so that together they cover the surface area to be printed. The printheads can also be arranged elsewhere in the film production process, for example in the form of an array before or during the reeling of the film. Since foil hoses are produced in the case of blown film systems and, if necessary, also rolled up in tubular form, the attachment of such arrays on both sides can be expedient. However, this variant would have the disadvantage of shorter drying times compared to the first embodiment due to the small distance to be covered up until rolling up. If necessary, the print heads can also be integrated directly into the film spray nozzles (eg the ring nozzle) of the film production line.

In a third embodiment, the described printing device, for example in the form of an array, can also be attached to a cast extrusion line (flat extruder). In such film making plants, the plastic is extruded between rolls and then rolled to a flat sheet. Here, the attachment of the printheads could be done at the point where the film has reached its full dimension, ie before the reeling of the film web. Also conceivable is an earlier printing of the film, wherein the then following dimensional changes would in turn be compensated by prior adaptation of the digitally generated print image.

The arrangement of the printheads can also be done completely free and must only ensure that the part of the surface to be printed is completely covered. The coordination of the individual printheads would again be done by corresponding measuring points and image converter or control software. Here too, further devices for quality assurance and labeling of individual batches etc. can be attached.

In a fourth embodiment, the device described may be mounted on an aluminum rolling line for the production of tapes and foils, etc., or a textile machine, etc., the above description being analogously transferable so that one or both forming material surfaces are printed as soon as they are finished essentially reached the final dimension. In the case of a textile machine, this would take place between the formation of the complete web and the rolling up of that web, in a metal foil production line, between the attainment of the desired dimensions (width and thickness) and rolling or destacking.

Claims (6)

Device in a blown film, on a cast extrusion line, on a rolling line for metal foils or on a manufacturing plant for textile materials, wherein a film, metal or textile web is printed directly during their manufacture immediately without contact by color nozzles with a printed image as soon as a has formed suitable surface, without a previous intermediate storage or removal of the film, metal or textile web takes place, so that within one and the same system, without physical and temporal interruption, both the production of foil, metal or textile web made of a raw or pulp as well as the printing done. Apparatus according to claim 1, characterized in that the device is in a film blowing unit and the printing of the film web by means of coordinated, annular or in any position about one or in the forming film tube arranged printheads takes place. Apparatus according to claim 1, characterized in that the printing device described in a line or arbitrarily distributed, one or both sides of a cast extrusion line, a rolling line for metal foils or attached to a manufacturing plant for textile materials. A process for printing a film or textile web produced in a blown film line, a cast extrusion line, a rolling line for metal foils or a production plant for textile materials, wherein the film or textile web is printed immediately contactless by color nozzles with a printed image during their manufacture immediately has formed a suitable surface without a previous intermediate storage or removal of the film or textile web takes place, so that within one and the same system without physical and temporal interruption, both the production of films, metal or textile web of a raw or pulp as well as the printing done, with a position and a size of the printed image are adapted by a metrological detection and subsequent modification to the location and dimension of the films, metal or textile web. A process for printing a film web produced in a blown film, wherein the film web is immediately printed immediately without contact through color nozzles with a printed image as soon as a suitable surface has formed, without any previous intermediate storage or removal of the film web takes place, so that within one and the same system, without spatial and temporal interruption, both the production of the film web from a raw or pulp as well as the printing done, the printing of the film web without interruption of the process before rolling, flattening, cutting, further processing or stacking the film web takes place, and wherein this printing is done from both sides by inside and outside of a film tube of Folienblasanlage positioned printheads. A process for printing on a film or textile web produced in a cast extrusion line, a rolling train or a production plant for textile materials, wherein the film or textile web is immediately printed immediately contactless through color nozzles with a printed image during their production, as soon as a suitable surface has formed without a previous intermediate storage or removal of the film or textile web takes place, so that within the same system, without spatial and temporal interruption, both the production of the film or textile web from a raw or pulp as well as the printing done wherein the printing of the film or textile web takes place without interruption of the process before rolling up, flattening, dividing, further processing or destacking the film or textile web, and wherein this printing takes place from both sides by oppositely arranged printing devices.

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