EP1324877B1 - Device for embossing and satin-finishing a flat material - Google Patents

Abstract

A device for satinizing and simultaneously embossing flat materials that includes at least two embossing rolls. One roll is connected to a driving system. The rolls are adapted to be driven individually or in common and are adapted to be resiliently applied against each other. Pyramidal or conical teeth of the rolls have flattened tips. The teeth of at least one roll are shaped so as to produce embossed signs in corresponding locations of the passing flat material so that the appearance of the embossed signs changes according to at least one of a viewing angle of the observer, a kind, and the position of the lighting source.

Description

The present invention relates to a device for glazing and simultaneous embossing of packaging films according to the preamble of claim 1 and to the packaging films produced according to the device according to claim 8.

A device according to the preamble of claim 1 is known for example from US-A-5 007 271 or EP-B-925 911 of the same Applicant. The apparatus for calendering a film described therein comprises two embossing rolls arranged mutually movably such that when the teeth of the embossing rolls intermesh, a self-stabilizing effect occurs, whereby a high throughput speed on the one hand and a high precision on the other hand is achieved. This results especially in a uniform satin finish and with appropriate removal of teeth a very precise embossing of films, at these points the surface of the packaging film remains untreated.

In EP-A2-0 194 042 an embossed article is disclosed, on the substrate of which first and second non-flexing relief elements are impressed defining first and second patterns and wherein the patterns uniformly reflect and change their view upon changing the viewing angle , The description only mentions line patterns and no satin finish is provided.

Starting from the state of the art according to US-A-5 007 271 or EP-B-925 911 in terms of embossing and calendering quality and the other prior art, the desire and the need and thus the object of the present invention has developed, to provide a device for producing embossments, the characters on the packaging film with location and / or light source dependent optical effects that also allow to create security features that are very difficult to copy.

This object is achieved with the device according to claim 1. Further advantages and features are defined in the dependent claims. A embossed with such a device packaging film is defined in claim 8.

Figur 1

zeigt eine schematische Darstellung der Abwicklung einer konventionellen Verzahnung einer Satinierwalze,

Figur 2

zeigt die stabile Eingriffstellung von konventionellen Verzahnungen von zwei Satinierwalzen,

Figur 3

zeigt eine konventionelle Verzahnung im vergrösserten Massstab,

Figur 4

zeigt im gleichen Massstab wie in Figur 3 eine Verzahnung gemäss Erfindung,

Figur 5

zeigt die stabile Eingriffstellung von erfindungsgemässen Verzahnungen von zwei Satinierwalzen, die

Figuren 6A-6F

zeigen die Wirkung einer erfindungsgemässen Spezialprägung anhand eines Zeichens, und

Figur 7

zeigt eine mögliche Anordnung von mehreren prägten Zeichen.

The invention will be explained in more detail below with reference to drawings of exemplary embodiments.

FIG. 1

shows a schematic representation of the development of a conventional toothing of a calendering roll,

FIG. 2

shows the stable engaged position of conventional gears of two satin rollers,

FIG. 3

shows a conventional gearing on an enlarged scale,

FIG. 4

shows on the same scale as in Figure 3 a toothing according to the invention,

FIG. 5

shows the stable engagement position of inventive teeth of two calender rolls, the

Figures 6A-6F

show the effect of a special embossing according to the invention on the basis of a sign, and

FIG. 7

shows a possible arrangement of several embossed characters.

For the basic structure of a calender, reference is made to US-A-5 007 271 of the same Applicant. A foil strip is made between two toothed tempering rollers made of hardened steel or a hard material, one of which is fixedly mounted and driven, while the other is freely rotatably mounted on an axle and by spring force, pneumatic or otherwise yielding with adjustable pressure against the driven roller can be pressed.

In the apparatus according to EP-B-925 911, which also relates to US-A-5 007 271, both satinizing rollers have a similar surface toothing, which is shown schematically in Figure 1 in development. These are pyramidal teeth, which are arranged in the circumferential direction or in the direction of rotation indicated by the arrow and in the axial direction at right angles to it in rows. According to Figure 2, the tooth tips are flattened, in practice, this reduction is at least 2%, preferably up to 25% of the theoretical geometric tooth height. In addition, the edges of the pyramidal or truncated pyramidal teeth are expediently broken. Instead of pyramidal teeth and conical, or frusto-conical teeth can be used.

In a preferred embodiment according to the above document, the rollers have a relative axial play of at least half a tooth pitch, preferably 0.75 times the tooth pitch, whereby they are mutually displaceable, so that they can move each other to a stable position.

While both rollers have the same teeth in these prior art calendering rollers, it has been recognized that providing at least one roller with teeth of different design, in particular tooth height and tooth surface, allows embossing, for example as Shadow embossments can be defined by seeing the embossed in the satin background, depending on the viewer's perspective and / or direction and type of illumination source with varying intensity and to form a shadow-like appearance.

Of course, the geometric center lines of the teeth, the screening, always have the same distance, otherwise a synchronization or self-synchronization is not possible. For technical reasons, it is also advisable to use teeth with the same layout, so that the variations in either the tooth height or in the design of the tooth flanks and / or edges and / or design of the surface such as roughening, grooves or patterns or in combination two or all sizes.

In the embodiment according to Figure 4 can be seen two teeth T1, which are shaped like the teeth according to Figures 1-3, which all have the same geometric dimensions and produce a normal satin finish and in Figure 4 left, the teeth T2, for example, a have lower tooth height, but could also have other tooth flanks or a different surface. In the case of the previously known embossing, the teeth are completely removed at the location where the characters are to appear on the film.

In principle, the teeth T2 having a different height, shape or surface than the teeth T1 may somehow be arranged, but it will be advantageous to choose the teeth T2 in a particular arrangement to produce patterns, letters or other signs. In Figure 4 is a simple arrangement represented, for example, the letter L results. The arrangement of the teeth T2 in such a configuration, this letter is generated such that depending on the viewing angle, a high to low contrast, or a large or small intensity is obtained, here assuming that the illumination source is constant and at the same Location is located. Otherwise, the location and / or wavelength of the illumination source can be varied and the observer can always look at the sign from the same angle, or both the viewing angle and the light source change. In principle, the result is always the same, the appearance of the character changes when one or both or all parameters change.

In FIGS. 6A, B, C, the respective observer is designated by an "O", wherein the arrow indicates the viewing angle and the observer looks at a satin-finished foil with shadow-embossed L, namely from top right, top or left, positions 6A , B, C, the contrast according to 6D being high, 6E being low and 6F being medium. In this case, a constant lighting is required.

For example, Figure 7 shows how it is possible to arrange groups of characters differently to combine different features or to produce particular codes. From Figure 7 it can be seen that at a given viewing angle and exposure LS from a particular location the letter "L" is weak depending on the situation, M up and right, very weak, N top right, middle strong, P down and left and whole strong, Q appears lower left. As explained with reference to FIG. 6, the appearance of a character changes as the viewing angle changes, but also as the change in the angle of view Lighting source in terms of location and exposure type, brightness and wavelength.

For the sake of simplicity, the same character "L" has been used in FIG. 7, it being understood that they may be any characters or numerals. This method can be well used for coding security features, and also a number string that can change can be used.

It thus follows that these special effects can be produced on the packaging tapes, films or boxes in very great variation, whereby these effects can be generated from any angle and the viewing angle and / or the illumination source can be varied. These effects, which depend on the viewing angle or on the illumination or on the wavelength of the light, are generated by the design teeth. Thus, for example, changes in the arrangement or configuration of the tooth flanks and / or edges also result from the viewing angle and illumination dependent effects, which are generally caused by the fact that the teeth have very small dimensions, so that changes in the tooth shape or tooth surface design of the characters causative teeth on the embossed object as a result of various kinds of light reflections or light diffraction optical effects that depend on the angular position, able to cause.

Such indicia may be applied to packages of tobacco, cigarettes, food, chocolate, medicines or the like. Such packaging tapes or foils consist predominantly of aluminum or predominantly of paper that is easy to fold. Recently, for environmental protection reasons, the material to be embossed has become developed further, that the media to be embossed, including metallized paper, while reducing the metallized layer thickness have a strong Fung such that the favorable folding behavior has deteriorated sustainable. This may be the case even if a plastic pad is used instead of paper. At present, a distinction is made between a multilayer film with a base made of paper and a layer of metal and a film with a vapor-deposited, thin metallization layer.

Until now, the embossments with the mentioned optical effects were discussed on the basis of a roller system with two embossing rollers. In order to take into account in particular the developments of the material to be embossed described above, or its lower metallization, and this extends both the scope and the production possibilities of such imprints with optical effects, a device for the treatment of flat material is used as advantageous in the application WO 00/69622, this PCT application is not vorpubliziert. In this device, the second embossing roll is followed by at least one further embossing roll cooperating with the first or preceding embossing roll in order to obtain the essentially identical pattern in a reimpregnation. This arrangement may be modified such that the stamping does not imprint the same pattern, but the above-mentioned imprinting with optical effects is obtained by having teeth with other geometrical dimensions and / or other surface design thereon or on one or more of the at least three Embossing rollers are arranged.

In this application is also listed that the embossing rollers can be synchronized with each other via synchronization means and also the present invention is not limited to embossing rollers, of which is mounted such that they in the longitudinal direction of the axis and / or in the pressing direction and / or in the direction of movement of the material to be embossed is deflected to allow self-synchronization. In addition, one tooth of a roller does not necessarily intervene between four adjacent teeth of the other roller, as in Figure 3, where the case of the so-called pinup-pinup configuration is shown, in which the teeth of all rollers facing outward. Rather, in the case of the embossings according to the invention, it may be expedient to forcibly synchronize embossing rolls with one another, wherein it is then also possible to use a so-called pinup-pindown configuration in which the teeth of a roll point outwards and the teeth of a cooperating roll point inward.

With the above arrangements not only variable optical effects can be generated by embossing but also security features that are very tamper-proof and usually detectable by the eye. Such security features can be used, for example, for expensive medicines, electronic articles or in the tobacco industry.

Claims (8)

1. Device for satinizing and simultaneously embossing packaging foils having a metallised surface or consisting of metal, comprising at least two embossing rolls that are connected to a driving system and capable of being driven individually or in common, the rolls being adapted to be resiliently pressed against each other and the interpenetrating pyramidal or conical teeth of the rolls having flattened tips, characterised in that pyramidal or conical teeth (T2) of at least one roll have a different geometrical shape and/or surface than the teeth (T1) that are intended for satinizing in order to produce embossed signs (L) that modify the metallised surface of the packaging foil and whose appearance changes according to the viewing angle of the observer (O) and/or the kind and/or the position of the lighting source (LS) in these locations during the passage of the packaging foil.
2. Device according to claim 1, characterised in that the different teeth (T2) have a smaller height than the remaining teeth (T1).
3. Device according to claim 1 or 2, characterised in that the different teeth (T2) have differently shaped flanks or edges than the remaining teeth (T1).
4. Device according to one of claims 1 to 3, characterised in that the surface of the flattened portion of the different teeth (T2) is structured.
5. Device according to one of claims 1 to 4, characterised in that it comprises two embossing rolls and the second embossing roll is followed by at least another embossing roll that cooperates with the first or preceding embossing roll in order to produce the signs of changing appearance in a subsequent re-embossing process, the different teeth (T2) being provided on one or on several ones of the rolls.
6. Device according to one of claims 1 to 5, characterised in that the embossing rolls are mutually synchronised by synchronising means.
7. Device according to one of claims 1 to 6, characterised in that at least one of the non-driven rolls is journalled such as to be capable of an excursion in the longitudinal direction of the axle and/or in the direction of the contact pressure and/or in the travelling direction of the material that is to be embossed.
8. Packaging foil produced using a device according to one of claims 1 to 7, which is satinized and provided on this satinized background with at least one sign (L) whose intensity changes according to the viewing angle (O) and/or the kind and/or the position of the lighting source (LS), characterised in that it comprises at least one group of signs (L) having the same appearance individually, in pairs, or in groups.

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