There is often the problem, in the business environment, of leaving a possible customer with specific articles of value for appraisal with restricted access, for example simply in order to inspect them. Thus, for example, picture agencies send their proposed pictures to an advertising agency for inspection in the form of a slide.

The advertising agency can then decide whether it wants to purchase the proposed picture or not. In the first instance, it opens the case, copies or scans the slide and pays the agreed fee. However, if the proposed picture does not appeal to the potential customer, he is supposed to return it. The invention is to prevent the customer from copying the slide or photograph and then returning the proposed picture on the grounds that he does not want to make use of it.

The latter instance could, admittedly, be prevented by welding the slide showing the proposed picture, or photograph, into a case or gluing it in in such a way that the slide or other article can be taken out only by destroying the case.

This would have the disadvantage, however, that the case can no longer be used as a storage folder, which is annoying, above all when, as is usually the case, useful information on the article of value is also recorded on the case.

Description of the Prlor Art US-5,060,848 discloses a sealable container having a closure with a coating which irreversibly indicates that the container has been opened for the first time. However, the container is not suitable for placing articles of value for visual appraisal. In the known container, access to the article of value can also be easily gained by bypassing the sealing closure, for example if the container is opened along an adhesive fold.

SUMMARY OF THE INVENTION The object on which the invention is based is, therefore, to provide a case for sealing in a flat article of value, preferably for the visual presentation of the latter, which ensures that the first-time opening of the case is indicated unmistakably and reliably and which is nevertheless not destroyed and rendered useless by opening.

This object is achieved by means of a case for sealing in a flat article of value, with at least one base layer, with a reception region for placing the article of value, said reception region being arranged on the base layer, with at least one sealing region arranged on the reception region at the edge, with at least one covering layer which can be fastened over the reception region and the sealing region, and with a coating which, after the covering layer has been fastened to the base layer, irreversibly indicates that the covering layer has been separated from the base layer.

A case according to the invention can be used for the sealing in and the visual presentation of flat articles of value of all kinds, such as, for example, photographs, slides, coins or mailing stamps. The case can easily be opened and then reused, in particular even reclosed, without being destroyed. However, the first-time opening is irreversibly indicated, so that, if the article of value is returned in the closed case, it is evident that someone could have had access to the article of value and copied, exchanged or falsified it. With the case closed, it is not possible to take the article of value out of the case without triggering the indication of first opening, since the article of value is, as it were, enclosed by the sealing region. The article of value does not necessarily have to be enclosed without any gap for this purpose. On the contrary, it is sufficient if the largest gap between the individual part regions of the sealing region is no larger than the smallest dimension of the article of value to be sealed in.

Also, the article of value does not necessarily need to be protected by the sealing region on a side on which protection is achieved in another way.

According to an advantageous embodiment of the invention, there is provision for the covering layer to have an adhesive layer corresponding to the shape of the sealing region. This adhesive layer may be protected, before use, with an adhesive-repelling protective film. According to an alternative design variant, the adhesive layer is arranged on the base layer.

Pressure-sensitive adhesives are particularly suitable as the adhesive sealing the case, since they do not require any activation, apart from the fact that a protective paper has to be removed.

However, the use of a water-activatable adhesive is also advantageous.

According to an advantageous embodiment according to the invention, the coating for indicating the first-time opening comprises at least one color layer which bonds with a first adhesive force to the base layer and with a second adhesive force to the covering layer when the covering layer is fastened to the base layer. Furthermore, there are adhesive force setting means which locally set the ratio between the first adhesive force and the second adhesive force differently.

When the covering layer is separated from the base layer in order to open the case, the color layer remains adhering partially to the covering layer and partially to the base layer. An irreversible optical change in the case thereby occurs. Even when the case is glued together again after being opened, the color layer has different reflection properties, since air, which modifies the visual impression of the color layer irreversibly and in a clearly perceptible manner, has entered between the color layer and the base layer or between the color layer and the covering layer.

A particularly advantageous embodiment of the case according to the invention is defined in that the adhesive force setting means comprise treatment of the base layer and/or of the covering layer in places. Films must undergo pretreatment before printing, in order to ensure that the printing ink bonds intensively with the film and a durable printing image is thus produced. If specific regions of the film of the case are omitted from printing pretreatment, for* example by being covered, the color layer applied there bonds only inadequately, and, when there is separation between the base layer and the covering layer, the color layer will remain adhering to that of the two parts which has undergone the printing pretreatment. The desired color layer separation effect during the opening of the case can thereby be achieved by the simplest possible means.

Alternatively or in addition to this, it may be advantageous to use as adhesive force setting means an antiadhesive lacquer which is applied in places. In particular the antiadhesive lacquer can easily be printed on in the form of a pattern or in the form of lettering, so that a particular image, such as, for example, the word "OPENED", becomes visible when the two parts are separated.

In addition or alternatively to this, the adhesive force setting means may comprise an adhesion promoter (Primer) which is applied in places. Such an adhesion promoter, which makes a particularly intimate bond between the printing ink and the background, can be applied in a simple way by printing.

A critical factor in all adhesive force setting means is that they influence the ratio of the forces with which the color layer bonds to the base layer, on the one hand, and to the covering layer, on the other hand, in such a way that, in places, the force of adhesion to one of the two parts is greater than the other of the two parts, so that, when the two parts are separated, the color layer is divided according to a specific pattern, that is to say part of the color layer remains on the base layer and the remaining part of the color layer remains on the covering layer. The adhesive coating ensures that the color layer bonds with an accurately settable force to the region coated with adhesive.

Said coating may be applied either to the base layer or to the covering layer selectively.

Furthermore, the use of a transparent film as a base layer and/or covering layer is advantageous, said film preferably being inked or printed with a nonopaque light color. In such a case, a particularly marked contrast is obtained between the various regions of the color layer if the two layers are glued together again after the first opening of the case.

A particularly perceptible contrast effect is also obtained when the color layer has a dark and/or opaque color.

The fact that the opening of the case has taken place is revealed particularly clearly if, according to a further particularly advantageous embodiment of the invention, a film deformable by stretching is used as the covering layer or base layer. In order to release the two parts of the case from one another and open the case, force must necessarily be exerted on the case. Under these circumstances, the covering layer and/or the base layer is permanently deformed, so that, when the case is reclosed, the separated parts of the color layer no longer fit exactly into one another geometrically, as a result of which the fact that opening has taken place is indicated in a particularly striking way.

If the adhesive force setting means are provided, at least in places, in the form of a pattern of lines, dots or the like, a structural or color change becomes clearly visible, even if there is only a very small geometric deviation in position between the two parts, after the covering layer has been glued back onto the base layer.

Preferably, the covering layer is provided with an imprint which may contain information on the content of the article of value sealed in the case. However, the imprint may also contain complicated geometric figures or coats of arms which cannot easily be simulated and thereby ensure originality. In this instance, it is advantageous if the imprint is sealed or protected by a laminate layer. Also, regions for subsequent inscription by hand or by means of conventional printers may be provided on the covering layer. By means of appropriate imprints, for example, a photograph or a slide sealed in the case can be provided with a frame (Passe-partout).

Dishonest attempts to open the case with the aid of heat, in order to reach the sealed-in article of value by bypassing the first-opening indicator function, are frustrated due to the fact that, according to a particularly advantageous embodiment, the case has a temperature indicator. This temperature indicator, which may be bonded, for example, to the base layer, changes color irreversibly under heating, so that the attempt to open the case becomes perceptible.

According to a particularly advantageous embodiment of the invention, there is provision for producing the covering layer by folding round part of the base layer.

The invention also relates to a method for producing a case for sealing in a flat article of value, with at least one base layer, with a reception region for placing the article of value, said reception region being arranged on the base layer, with at least one sealing region arranged on the reception region at the edge, and with at least one covering layer which is fastened over the reception region and the sealing region, in which a first material web for producing the base layer is supplied and is given at intervals the articles of value to be sealed in, and the covering layer is fastened over the articles of value and is sealed to the base layer in the sealing region.

According to a first advantageous embodiment of the method, the covering layer is produced by folding round the first material web.

According to an advantageous design variant of the method, the covering layer is produced from a second material web which is laminated onto the first material web.

There is no need for a folding-round device in this design variant.

The invention also relates to an apparatus for producing a case for sealing in a flat article of value, with at least one base layer, with a reception region for placing the article of value, said reception region being arranged on the base layer, with at least one sealing region arranged on the reception region at the edge and with at least one covering layer which is fastened over the reception region and the sealing region, with a guide for a first material web for producing the base layer and with a folding-round device for automatically folding round and sealing the material web.

Furthermore, the invention also relates to an apparatus for producing a case for sealing in a flat article of value, with at least one base layer, with a reception region for placing the article of value, said reception region being arranged on the base layer, with at least one sealing region arranged on the reception region at the edge and with at least one covering layer which is fastened over the reception region and the sealing region, with a guide for a first material web for producing the base layer and with a second guide for a second material web for producing the covering layer and a sealing device for bonding the two material webs in the sealing region.

Further advantageous embodiments may be gathered from the subclaims.

The invention is explained in more detail below with reference to the exemplary embodiments illustrated diagrammatically in Figures 1 to 9. The illustrations are not true to scale, in particular the thicknesses of the individual layers are shown greatly enlarged, as compared with the other dimensions of the case, for the sake of clear illustration.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a top view of an opened case for sealing in a flat article of value according to the invention.

Figure 2 shows a central longitudinal section through the opened case shown in Figure 1.

Figure 3 shows a longitudinal section through the case in the closed state.

Figure 4 shows a top view of a further embodiment of the case.

Figure 5 shows a central longitudinal section through the case from Figure 4.

Figure 6 shows a longitudinal section through a further embodiment.

Figure 7 shows a top view of a further embodiment of the case.

Figure 8 shows a first embodiment of an apparatus for producing a case.

Figure 9 shows a second embodiment of an apparatus for producing a case.

DESCRIPTION OF THE PREFERRED EMBODIMENT The case shown in Figure 1 comprises a rectangular transparent film piece which is subdivided into a base layer 2 and a covering layer 5 by means of a folding line 13.

Provided on the base layer 2 is a reception region 3, on which an article of value 1 is placed. The article of value 1 is fastened there by means of a layer of releasable adhesive (which cannot be seen in the illustration of Figure 1). The reception region is surrounded all round by a sealing region 4.

Contrary to the variant chosen in Figure 1, it will also be possible for the sealing region to have interruptions or to consist of only a few spots, if this ensures, in the individual instance, that the article of value is reliably prevented from being taken out, with the case closed.

Arranged on the covering layer 5 is an adhesive layer 6 which corresponds in its shape and position to the sealing region 4, that is to say, when the film piece consisting of the two layers 2 and 5 is folded round the folding line 13, the adhesive layer 6 rests on the sealing region 4.

The transparent film piece, which is composed of the base layer 2 and of the covering layer 5, can be seen again in the sectional illustration of Figure 2. The peripheral pressure-sensitive adhesive layer 6 can be seen again on the covering layer 5. Provided on the opposite side carrying the pressure-sensitive adhesive layer 6 is an imprint which is indicated symbolically by the two black bars 10a and lOb.

The article of value 1, which bonds to the base layer 2 by means of a layer of lightly bonding adhesive 12, can also been seen in the region of the base layer 2 in the sectional illustration of Figure 2. The sealing region surrounding the article of value 1 or the reception region of the latter has a coating which is composed as follows. Arranged on the base layer 2 is an adhesive force setting means comprising an antiadhesive lacquer 8 which is applied in places and which is, for example, a silicone lacquer. The antiadhesive lacquer is applied in the form of a special geometric pattern or of lettering, such as, for example, in the form of the word"OPENED". A continuous layer of an adhesion promoter 9 is printed on over this locally printed-on layer of antiadhesive lacquer 8. The adhesion promoter layer 9 is covered with a color layer 7 which has been printed onto the adhesion promoter layer 9. A temperature indicator 11 is arranged on that side of the base layer 2 which is located opposite the coating described.

After the covering layer 5 has been folded round onto the base layer 2, as indicated by the arrow P in Figure 2, the color layer 7 bonds to the adhesive layer 6 of the covering layer 5 with a first adhesive force and that side of the color layer 7 which faces the base layer 2 bonds to the latter with a second adhesive force. The ratio of the two adhesive forces is varied locally by the adhesive force setting means consisting of the antiadhesive lacquer 8 and of the adhesion promoter 9, so that the first adhesive force is greater than the second adhesive force in the regions with antiadhesive lacquer 8 and the first adhesive force is lower than the second adhesive force in the regions without antiadhesive lacquer 8.

The closed case is illustrated in longitudinal section in Figure 3. The article of value 1 can be viewed through the transparent covering layer 5, but cannot be extracted without the case being opened. Even if a transparent plastic foil is used as covering layer 5 copies of the article of value cannot be made, because the optical reflections occurring at the surfaces of the transparent foil and even a few scratches which are usually present in the foil would have such an adverse effect on the quality of the copy so that it would not be useable for professional applications as required by picture agencies for instance. The covering layer 5 may additionally contain a stripe pattern or similar means which does not disturb viewing, but prevents usable copies from being made. Such means could be for instance a small image or a word, such as"SAMPLE"printed on it.

The closed case can be opened by lifting the covering layer 5. The color layer 7 bonds firmly to the base layer 2 as a result of the action of the adhesion promoter 9, with the exception of those places which were prepared with antiadhesive lacquer 8 before the application of the adhesion promoter. These places are torn out from the base layer 2 due to the action of the adhesive layer 6 when the covering layer 5 is pulled off and remain on the adhesive layer 6, that is to say on the covering layer 5.

When the base layer 2 and the covering layer 5 are subsequently glued together again, the part which has remained on the covering layer, that is to say that part of the color layer 7 which was also torn by the adhesive layer 6, could, admittedly, be inserted again into the gaps of the color layer which have occurred. However, since air has penetrated between the color layer 7 and the base layer 2 due to parts of the color layer 7 being torn out, these parts have changed light reflection behavior, as compared with the parts of the color layer 7 which have remained on the base layer 2. This can be observed through the transparent covering layer 5, so that the opening operation is clearly revealed.

If heat is used, the temperature indicator 11 changes color irreversibly and indicates that an attempt has been made to open the case by supplying heat, bypassing the indicator function described above.

The print 10a, 10b arranged on the covering layer 5 may comprise important data relating to the sealed-in article of value or else a frame for the latter.

The case shown in Figure 4 comprises, once again, a rectangular transparent film piece which is subdivided into a base layer 2 and a covering layer 5 by a folding line 13.

A reception region 3, on which an article of value 1 is placed, is provided on the base layer 2. The article of value 1 is fastened there by means of a layer of releasable adhesive (which cannot be seen in the illustration of Figure 4). The reception region is surrounded all round by a sealing region 4. That layer of the sealing region 4 which is located on the very top in the illustration of Figure 4 is an adhesive layer 6 which corresponds in its shape to the sealing region 4.

The transparent film piece, which is composed of the base layer 2 and of the covering layer 5, can be seen again in the sectional illustration of Figure 5. Contrary to the exemplary embodiment of Figures 1 to 3, the covering layer 5 has only an imprint which is indicated symbolically by the two black bars 10a and lOb.

The article of value 1, which bonds to the base layer 2 by means of a layer of lightly bonding adhesive 12, can also be seen in the region of the base layer 2 in the sectional illustration of Figure 2. The sealing region surrounding the article of value 1 or the reception region of the latter has a coating which is composed as follows. Arranged on the base layer 2 is an adhesive force setting means comprising an antiadhesive lacquer 8 which is applied in places and which is, for example, a silicone lacquer. The antiadhesive lacquer is applied in the form of a special geometric pattern or of lettering, such as, for example, in the form of the word"OPENED". A continuous layer of an adhesion promoter 9 is printed on over this locally printed-on layer of antiadhesive lacquer 8. The adhesion promoter layer 9 is covered with a color layer 7 which has been printed onto the adhesion promoter layer 9. The color layer 7 is covered with an adhesive layer 6.

A temperature indicator 11 is arranged on that side of the base layer 2 which is located opposite the coating described.

The case is handled in the same way as described in connection with the case of Figures 1 to 3, so that a renewed description may be dispensed with.

The further exemplary embodiment of a case according to the invention, shown in longitudinal section in Figure 6, comprises, once again, a transparent film piece which is composed of the base layer 2 and of the covering layer 5.

The peripheral pressure-sensitive adhesive layer 6 can be seen on the base layer 2. A temperature indicator 11 is arranged on the opposite side carrying the pressure- sensitive adhesive layer 6.

The article of value 1, which bonds to the base layer 2 by means of a layer of lightly bonding adhesive 12, can also be seen in the region of the base layer 2 in the sectional illustration of Figure 6.

Provided on the covering layer 5 is a coating which corresponds in its shape and position to the pressure- sensitive adhesive layer 6 and which is composed as follows: Arranged on the covering layer 5 is an adhesive force setting means comprising an antiadhesive lacquer 8 which is applied in places and which is, for example, a silicone lacquer. The antiadhesive lacquer is applied in the form of a special geometric pattern or of lettering, such as, for example, in the form of the word"OPENED". A continuous layer of an adhesion promoter 9 is printed on over this locally printed-on layer of antiadhesive lacquer 8. The adhesion promoter layer 9 is covered with a color layer 7 which has been printed onto the adhesion promoter layer 9.

An imprint, which is symbolized by the black bars 10a and 10b, is arranged on that side of the covering layer 5 which is located opposite the coating described.

The case is handled in the same way as described in connection with the case of Figures 1 to 3, so that a renewed description may be dispensed with.

In the exemplary embodiments described, the covering layer 5 and the base layer 2 are produced by folding round a film piece. The base layer 2 and the covering layer 5 may, of course, also be produced from separate film pieces. The advantage of such a variant is that the materials of the covering layer and base layer can be selected independently of one another. Thus, for example the base layer may be made from opaque basic material and the covering layer from transparent basic material.

The case shown in Figure 7 comprises, once again, a rectangular transparent film piece which is subdivided into a base layer 2 and a covering layer 5 by a folding line 13.

A reception region 3, on which an article of value 1 is placed, is provided on the base layer 2. The article of value 1 is fastened there by means of a layer of releasable adhesive 12. The exemplary embodiment of Figure 7 corresponds thus far to the exemplary embodiment of Figure 1. Contrary to the example shown in Figure 1, the sealing region 4 consists of three separate part regions which are arranged along the edge of the reception region 3. The reception region 3 is therefore surrounded on three sides by the sealing region 4, in such a way that the article of value 1 is reliably prevented from being taken out. This means that the largest gap between the individual part regions should be no larger than the smallest dimension of the article of value 1 to be sealed in. Arranging a sealing region on the side facing the folding line 13 was dispensed with, since the article of value 1 is protected on this side by the folded-round covering sheet. More space is thereby available for the article of value.

Arranged on the covering layer 5 is an adhesive layer 6 which corresponds in its shape and position to the sealing region 4, that is to say, when the film piece consisting of the two layers 2 and 5 is folded round the folding line 13, the adhesive layer 6 rests on the sealing region 4.

Figure 8 shows an apparatus for producing a case according to the invention. A material web 15 runs via an applicator device 21, that is to say a device with printing units or with coating appliances. The material web is printed or coated, in the applicator device, with various layers, such as the adhesive layer, the color layer, an antiadhesive lacquer or an adhesion promoter. Alternatively to this, this printing and/or coating may take place completely or partially in another apparatus in a preceding method step and a correspondingly preprocessed material web 15 may be used. Adhesive points on such a pretreated material web 15 may be covered by a protective film or the material web 15 may be wound on itself, the rear side of the material web 15 being provided with an adhesive-repelling smooth layer. If the adhesive points on the material web 15 are covered with a protective film, a pull-off or strip-off device, which is expediently integrated into the applicator device 21, must be provided for the protective film.

The material web 15 is also printed with a register mark in the applicator device 21 or in an earlier production step, said register mark being detected by a sensor 17a of a dispensing device 17 which keeps in stock various articles of value 1, each of which is dispensed, under the control of the sensor 17a, in such a way that it is dispensed onto the material web 15 in the correct positioning in relation to the sealing region provided on the material web 15. The material web 15 constitutes the base layer of the case.

A second material web 16, which forms the covering layer 5, is laminated onto the material web 15 given the articles of value 1. With the aid of a sealing device 20, the two material webs are bonded, so that the articles of value 1 are enclosed between the two material webs 15 and 16, that is to say between the base layer and the covering layer. The composite material web produced in this way runs through a printer 18, in which it can be printed with information on the article of value under the control of a computer 23. The article of value is detected, in the dispensing device 17, by the computer 23, so that the appropriate inscription can be allocated to said article of value, with some delay, when the latter enters the printer 18.

After leaving the printer 18, the composite material web is cut, as required, in the cutting unit 22, into portions which may contain one or more articles of value. If a plurality of articles of value are contained in one portion of the composite material web, it is advantageous if, in the cutting unit 22, a perforating punch is carried out, by means of which the composite material web may, if required, be divided by hand.

Figure 9 shows a further embodiment of the apparatus according to the invention. Contrary to the exemplary embodiment of Figure 8, in the exemplary embodiment of Figure 9 only a single material web 15 is provided. The latter, after being printed in the applicator device 21 and given the articles of value by means of the dispensing device 17, is automatically folded along its center line in a folding device 19, so that the material web 15 forms not only the base layer, but also at the same time the covering layer.

Inscription in the printer 18 is carried out in the same way as in the exemplary embodiment of Figure 8, so that, in this respect, reference should be made to this. The same applies to the cutting off or perforating of the material web in the cutting unit 22.

The articles of value 1 may, if desired, also be placed onto the material web 15 by hand. There is then no need for the dispensing device 17.