This invention refers to a method of verifying that a packet or container is unruptured so that for example no one has been able to introduce harmful or irrelevant substances therein and that the packet or container when being closed becomes tightly sealed. The method of the invention is characterised by a marking device being positioned on or in the packet or container for providing an indication if the packet or container is subjected to damage and is opened or is not tightly sealed. Further characteristics may be seen in the subclaims.

The invention can be applied for example if a product is to be packed in a machine and a test is to be carried out to see if the packet or container is sealed. After the packet or container has been sealed its tightness can be checked visually or automatically by reading/decoding the marking device.

It has at times occured recently that malicious people have manipulated with i.a. medication packets or containers, candy packets or containers, etc, and have introduced poison or other dangerous or irrelevant substances into the packet or container. For example, it has become general knowledge that some years ago medication packets or containers were manipulated in this manner in the United States and candy packets or containers were manipulated in Japan. This is a problem which has created considerable attention in the press and which frightens people.

The present invention has the purpose of preventing

such manipulation. This can be done by the above-mentioned marking device being designed in different ways. For example, it may consist of a label in a casing which communicates hermetically with the interior of the packet or container. The packet or container can in such case for example contain a gas which is unharmful to human beings, for example nitrogen gas. When the gas disappears in consequence of someone having ruptured the packet or container or the packet or container leaking, the label will change its colour. The label can be provided with a bar code, and in such case the bars or their substrate may change colours or one or more bars may swell out so as to provide a warning signal, or otherwise the bar code may be supplemented with one or more warning bars. An additional possibility is to stir the bars mechanically. Still another possibility is to retain the code instead of destroying it but to provide it with a new bar which reacts either to the gas or to the air or the mechanical rupture. Alternatively a bar existing earlier may be removed. The changes may be permanent or for a specific period (long or short) or for a specific time interval.

The above may be illustrated in a very simple manner, for example with a jar of baby food. The label, which if desired may be provided with a bar code, is placed in the cover or the jar or may comprise a portion of the cover or the jar and communicates with the interior of the jar. As long as the jar of baby food contains for example nitrogen gas nothing happens, but if someone has opened it and air has been introduced the label changes. Thus, the colour or the bar code of the label may be changed, for example mechanically, chemically, electrically or photoelectrically.

As may be seen above, the bar code may be changed if desired or its substrate may change its colour when air flows into the packet or container in consequence of one or more holes having been made in the packet or container or the packet or container having been opened. This discolouring may be such, that it may be seen directly in the shelf in the shop where the packet or container is

placed. Another possibility is to "stir" the bars so that they become illegible or that another bar combination is formed.

Instead of the label being positioned outside of the packet or container it may be placed in the same, or otherwise a locking device may exist between for example a cover and a jar so as to interconnect them by means of a bridge. If the bridge has been ruptured the packet or container has been opened. For example, in the above- mentioned jar for baby food a connection may exist from the glass casing to the cover, with said connection being ruptured when the cover is opened so as to provide a marking.

Alternatively, the marking device can comprise a portion of a gas and airproof packet or container casing, wherein the marking device is changed if the packet or container has been opened or damaged and leaks. The change may be indicated by air flowing into the casing instead of a gas or vacuum which is there from the beginning. The change may for example be in the colour of the marking device or a change of a bar code or some other code.

A possibility of detecting the change of the marking device on the relevant packet or container is that a bar code which is intended to be read by the reading pen of a cashier when a person passes out past the cashier's counter in a shop where the relevant person has purchased the packaged goods has been changed. If the packet or container has been opened the reading pen will immediately issue a warning of this, which may be done for example by an acoustical, visual or electrical signal being delivered when the reading pen passes the position of change. If a warning signal has been delivered a receipt signal has to be given to the readout apparatus that the warning signal is perceived before the reading apparatus can read and record the next marking device.

The packet or container may for example comprise a carton, a box, a soft package, a plastic bag, or a plastic jar or glass jar or a tin can etc. What is important is that

the marking device is positioned on the packet or container in such manner that if the packet or container is opened the marking device will change.

The marking device should appropriately be positioned on the packet or container at the place of manufacture where quality control of the packet or container is carried out. In this manner it is also possible to check the sealing of the package. If the marking device for example is to be affected by gas or vacuum an unaffected marking device indicates that the package leaks, i. e. that the gas has gone out and air has come in and that the vacuum has been suspended and air has come in, respectively. The function of the marking device is adapted to the relevant mode of sealing of the packet or container. As has been noted above the invention is not limited to box packages or jars, and it is also possible to have a soft package, for example a plastic bag around a pizza. If someone takes a hypodermic needle and injects something the immediate result is a hole where air comes into the packet which prior to that for example may be filled with a protective gas or vacuum packed. The bar code in the marking device may for example thereby change its colour.

The invention will be described more specifically below with reference to the accompanying drawings, in which Figures 1-5 show various applications of the invention and Figures 6A-6C show an example of how a bar code can change in connection with a marking device in accordance with the invention being affected.

Figure 1A shows a vacuum packet for meatballs 1 with an internal envelope 2 and an external envelope 3, between which two last-mentioned envelopes a gas which is harmless to food is introduced or a vacuum is created-. Through an opening 4 in the external envelope the space between the envelopes and thus the gas and vacuum, respectively, communicates with a marking device 5, for example a label which changes its colour if the gas or vacuum is replaced by air which enters in consequence of the external envelope 3 being punctured somewhere. The label may alternatively be

provided with a bar code which normally, i.e. when the relevant gas and vacuum exist between the internal and external envelopes, respectively, is proper but which changes its character if air enters between the envelopes. Figure 1B shows the envelope in accordance with Figure 1A, but with one single envelope and marking device. Figure 1C shows a packet with a single envelope and a marking device integrated therein. The function of the marking device is the same for all types in accordance with Figures 1A, 1B, and 1C, respectively.

Figure 2A shows a container 6 with contents 7 and with a member 8 for closing the container, to which a marking device 9 is attached, for example a label with or without a bar code. In the closure member 8 there is an aperture 10 which connects the interior of container 6 to the inside of label 9. Analogously to the conditions in Figures 1A-1C container 6 may include an appropriate gas or have a vacuum. If the interior of the container comes into contact with air, for example by the sealing member being opened, the rear side of label 9 is affected and provides a marking in analogous manner to what has been described in connection with Figure 1A. A corresponding description with the marking device on the container applies to Figure 2B.

A portion 8 of a packet or container may alternatively be provided with one or more indicating spots 11 and 12 as shown in Figure 3. If one of these, for example 11, is colourless or has a specific colour the packet or container has not been opened, whereas if the other one, for example 12, has changed its colour this means that the packet or container has been opened and that the colour spot 12 has turned into colour or has changed its colour in consequence of access of air. The change in colour may also mean a change from a condition with colour to colourless or vice versa, which latter is perceived from the above. Instead of colour spots, light sources can also be utilized in corresponding manner.

Figure 4A shows a further embodiment of a container 13 with a closure member 14 which in one embodiment can be

provided with a marking device 15 analogous to marking device 9 in Figure 2 but which is affected by the rear side being subjected to light or heat when the container 13 is opened and when the sealing member 14 is taken off of the container 13, respectively. In another embodiment a marking device 16 is connected both to the container 13 and to the sealing member 14 and is ruptured when the container is opened. If the sealing member is put in its place again a code disposed on the marking device 16 will not provide the right indication in readout for example by means of a reading pen.

Figure 5 shows a package 17 of ice cream with a marking device 18 which in anology to the above changes the colour or the pattern of a code marking if the temperature of the package of ice cream exceeds a predetermined value, i.e. if the ice cream is stored in an unpermittedly warm place.

Figures 6A-6C show three examples of a code marking and changes which it can go through if it is subjected for example to air after having been enclosed in gas or a vacuum or by having been actuated by heat or light. Figure 6A shows the code in its original form, i.e. unactuated, wherein the code as an example comprises four code markings 19, 20, 21, and 22, respectively. Figure 6B shows the marking device changed, with the original code marking 19-22 being retained, whereas a new code marking 23 has been added.

Figure 6C shows another example of a changed marking device in which the code markings 19, 21 and 22 still remain but the code marking 20 has disappeared. The marking device can have these changes permanently or for a specific time period (long or short) or for a predetermined time interval depending on how it is to function.

The invention is not restricted to the embodiments described above and shown in the drawings, and they may be varied to a high degree. Many other embodiments can also be contemplated. For example some of the changes of or by the marking device do not have to be registerable by the human eye, and they may for example be changes in computer codes or other markings that may be sensed in the marking device.