DE2021917A1 - Lid made of plastic film and method and device for producing this lid - Google Patents

Description

Plastic film cover and method and device for production this lid The invention relates to a plastic film consisting of with a raised circumferential edge provided cover, wherein the cover a has approximately U-shaped cross-section and for receiving the outer edge of a preferably also made of plastic film is used, and the surface (inner surface) has a print within the raised edge.

This cover made of a plastic film is used as a Closure for loose, cups and similar containers that are used to hold food or luxury foods which, after removing the cover, are intended to be used immediately; r to be consumed by the buyer. As a rule they are Life or luxury items of such cans or cups pasty, semi-liquid or liquid, although these cans or cups are also used to hold solid foods and / or luxury foods can serve. Examples of these goods are salads, margarine, fats, etc. called.

As a rule, the content of the food or luxury food can be similar Cans of the cups after they have been closed by the lid, only as Semi-preserved foods are called, whose limited shelf life a use of chemical Preservatives required.

Such cans or cups usually have round, rectangular ones and in particular a square base area without the formation of this base area is important for the invention.

The size of these cans or cups and, accordingly, the size of these However, lid is limited. As a rule, these cans contain more space or cup not the value of 1000 cm - 1 1.

The plastic film that makes up both these cans or cups as well their cover is relatively thin. Your strength is about 0.12 to 0.25 mm. The shaping both the lid and the container takes place in the usual way, in particular in the vacuum deep-drawing process, by the lid or the can or mug can be heated. With this deep drawing process an overpressure can be used instead of a vacuum. Warming is necessary the film made from a thermoplastic material. Usually serve for this purpose foils made of polyvinyl chloride (PVC) or a mixed polymer on the basis of FVO, a polyelefin (especially ethylene) or a polyether.

The inner surface of these lids is usually printed in the gravure printing process with the help of copper-coated gravure cylinders. The production the print image on these Tiedruckzylindern is quite expensive, so that this printing is only recommended for relatively large editions of lids. In addition, the inner surface of the lid is printed using the gravure printing process is only possible in such a way that the smooth, not yet deep-drawn or embossed Foil printed, and that only then is the production of the lid edge in the deep-drawing process v. is accepted. The distortion of the printed image remains within tolerable limits.

In order to also have smaller editions with tolerable production costs to press To be able to, it is also known to the inner surface in a so-called dry offset process to be printed. The printing form is supplied by relief printing clichés, i.e. by Clichés on which the printing image is intended to be raised. Usually takes place the cover more colored, for example three or four colors.

After coloring the cliché, the print image is transferred to a rubber blanket transferred, which is only now - in the offset process - the print image on the Transferring the inner surface of the lid, so its inner surface is printed. The usual The high pressure process was not feasible here because the compressive stresses were so high and also different are that the thin foil is too strongly embossed and not only is printed, and that the thin film may even be damaged.

On the other hand, modern sales methods are becoming increasingly popular the additional issue of discount stamps or point stamps as a basis for the Output of any series of pictures, etc. through. The invention is based on knowledge on that the issue of such discount or point stamps is best, safest and The simplest takes place in the form that the discount stamps, point stamps or the like form the packaging. For example, the brand itself could also be a part of a mosaic picture that by Composition with other drawing files can be combined to form an overall picture. In any case, this is an imprint Narkabohnittes required.

The inner surface that was previously intended for printing on the lid was, but is excluded as a means of delivering the dot mark or the like, because on the one hand, the raised edge of the lid makes it difficult to separate this point mark area and because, on the other hand, the inner surface of the lid is also unsightly due to the goods themselves may have become.

According to the invention, therefore, the lid outside the edge with a also provide a printed surface (outer surface) that is in the plane of the inner surface lies. Expediently, this outer surface protrudes from the outer edge by about 20 mm the edge out.

In the case of a lid with a square, in particular square, base is provided, wherein the corners can also be rounded, the invention takes place expediently in the form that the conditioned outer surface is arranged in one of the corners is.

Naturally, this printed outer surface can also be known per se Way as a tear-off flap to make it easier to open of the lid to serve. However, this printed outer surface is considerably larger than it is usually such tear-off tabs from lids, which consist of a plastic film, because the printing of the outer surface is necessary for the stated purposes requires a certain minimum size.

The invention is further to a method of making the so marked, provided with a printed outer surface lid directed. According to the invention, the cover is first made from an unprinted film with a raised Edge and outer surface are produced in a deep-drawing process, and then both the inner surface and the outer surface in one operation using the offset process printed with letterpress printing plates, i.e. letterpress Klishees. In this way it succeeds it, always flawlessly and undistorted, the respectively intended outer surface with the to print the intended print image.

This idea of the invention is expediently carried out in the form that two rubber blankets arranged at a distance from one another are assigned to the cover, wherein the one rubber blanket for receiving and transferring the print image for the inner surface and the other rubber blanket for receiving and transferring the print image for the outer surface serves. Between these two blankets are already running in Raised edge of the lid produced through the deep-drawing process.

The blankets are preferably arranged on printing segment pieces, which are exchangeably attached to a printing cylinder in a manner known per se.

Such an offset printing machine in which the deep-drawn lid with the help of fasteners attached to a transport device on the circumferential Printing cylinders can be moved past, is also characterized according to the invention by dadurcb, that they matched a part of the outer circumference of the raised edge of the lid Carriers are provided with outwardly protruding recesses that the to be printed Outer surfaces of the lid correspond. This way it will also look flawless Execution of the printing process with respect to the outer surface in the correct position brought the printing cliché.

Further improvements and expedient refinements of the invention are explained with reference to the accompanying figure, in which an exemplary embodiment the invention is shown in simplified form. Show it: Fig. 1 a Side view of an offset printing machine designed according to the invention, FIG. 2 a view on an enlarged scale of the driver formed according to the invention for bringing the already thermoformed plastic film cover up to the printing Place of the printing machine, FIG. 3 is a view on an enlarged scale of the printing cylinder the offset machine of Fig. 1, Fig. 4 a Binzelansiht on an according to the invention provided printing segment, FIG. 5 is a plan view of the printing cylinder of FIG. 3, FIG. 6 a view seen approximately in the direction of the arrow VI in FIG. 5, wherein however, to simplify the representation of both the impression cylinder and the impression cylinder viewed in the axial direction, FIG. 7 shows a plan view of a device according to the invention formed from a plastic F the lid made in the deep-drawing process, Fig. 8 shows a section along line VIll-VIll of FIG. 7, for example the associated Can, which is used to hold a salad, is also shown.

The Dae of Figs. 7 and 8 is denoted by 11 and has a lid 12 with a raised circumferential edge 9, which when closing the Can engages in the raised circumferential edge 13 of the can 11. The edge 13 has been produced by flanging the can film. In a familiar way the outer web 15 of the cover 12 is provided with inwardly facing depressions 16, the outwardly facing webs 17 are interrupted. Be that way the sealing of the can 11 and the holding of the lid on this can improved.

Both the lid and the can have an approximately square base with rounded ends. The theoretical outer edge of the lid is denoted by 14. The outer surface provided according to the invention and provided with a printed image 18 bears the reference number 8; its outer edge protrudes 21 mm above the theoretical Outer edge 14 of the cover so that a sufficiently large print image 18 with a diameter of about 13 mm results. With ier printing is at the same time eirs cutting line 19 depicting a Scissors 20 provided, to show the consumer that the outer surface 8 is cut off at this point after the lid has been opened. In the example, as Printing a dot mark provided, which is used to obtain images that distributed by a central image service. But it can also be any other Printing can be provided, for example also the part of a mosaic picture.

The outer surface 8 with its printing can also be designed differently so that it can act as an image on its own.

The offset printing machine shown in FIGS. 1-6 has a rotating and driven printing cylinder 1, an impression cylinder 3 and a A plurality of color cylinders arranged around the circumference of the printing cylinder 1 2 on.

A color is assigned to each of the ink cylinders in a known manner. The inking units themselves are not shown in particular. On the circumference of the printing cylinder are - in the exemplary embodiment three - inner surface pressure segments 4 interchangeable attached. They are provided with a rubber cover 21, which is part of a rubber blanket can be understood. In addition, there are outer surface printing segments on the printing cylinder 5 also provided interchangeably, which are shown in accordingly are provided with a rubber cover 22. The rubber layers 21 and 22 lie to the same extent. Between the two pressure segments 4 and 5 is how results in particular from FIGS. 5 and 6, a gap 6 is provided into which the raised Edge 9 of the cover 12 is able to enter. The ones provided on the ink cylinders 2 When the machine is in operation, clichés are created by the inking units (not shown) colored and transferred their print image to the rubber surfaces 21, 22, which are now-only again using the offset process to print the inner surface 7 and the outer surface 8 of the cover. The screws for exchangeable fastening of the pressure segments 4 and 5 on the Printing cylinders 1 are indicated at 23 and 24.

The individual lids 12, which are fully formed in the deep-drawing process fed to the printing point along a path 25 with the aid of drivers 1b, which are fastened, for example, to a revolving chain, not shown. The drivers 10 are shown on an enlarged scale in FIG. Your contour 26 is adapted to the outer circumference of the raised edge 9 of the lid. For execution the invention, the driver is also provided with a recess 27 which the Outer surface 8 is adapted. In this way it is ensured at the same time that the Outer surface 8 always correct with reference to the outer surface printed segmede 5 comes to rest - with whose rubber blanket the outer surfaces are to be printed. The individual lids are successively by means of the transport device 10-25 einer.Magazins supplied, which is known per se and is therefore not shown in any more detail and needs to be described.

In the exemplary embodiment, the offset printing machine is a dry offset machine executed with letterpress clichés, since such letterpress forms are particularly well suited for relatively short print runs. But if on the described Way, the offset printing machine is designed as a wet offset printing machine in area printing is to be, it is also possible without impairing the feasibility of the invention.

In one embodiment of the invention, for example, the cover has a base area of about 100 x 100 mm, the can in a corresponding manner a base area of about 90 x 90 mm and a height of about 20 mm. The numbers are given as examples only and are not intended to limit the invention to such dimensions.

The outer surface can also be used for offset printing of z. B.

Trademarks or quality seals are used that are particularly effective here.

Claims (7)

Fatentans check Made of a plastic film with embossed all around Lid provided with a rim, the rim having an approximately U-shaped cross section and for receiving the upper edge of a preferably also made of plastic film existing can is used, and where the area (inner surface) is within the raised Edge has a printing, characterized in that the lid outside the edge is also provided with a printed surface (8) (outer surface), which lies in the plane of the inner surface (7). 2. Lid according to claim 1, characterized in that the outer surface (8) protrudes about 20 mm from the outer edge of the rim. 3. Lid according to claim 1 and / or 2 with angular, in particular square Base area, whereby the corners can also be rounded, characterized in that that the printed outer surface (8) is arranged in one of the corners 4th Method for producing the lid according to one of Claims 1 to 3, characterized in that that first the cover with a raised edge (9) and outer surface from an unprinted film (8) is made in the deep-drawing process, and that then both the inner surface (7) as well as the outer surface (83 printed in one operation in the offset process will. 5. Offset printing machine for carrying out the method according to claim 4 for the purpose of producing lids according to one of claims 1 - 3, characterized in that that the cover (12) has two spaced-apart rubber blankets (21, 22) are assigned, the one rubber blanket (21) for receiving and transmitting the Print image for the inner surface (7) and the other rubber blanket (22). to record and transmission of the print image is used for the outer surface (8). 6. Offset printing machine according to claim 5, dadurcgekisiert that the blankets (21, 22) are arranged on pressure segment pieces (4, 5) which on are interchangeably attached to a printing cylinder (i) in a manner known per se. 7. Offset printing machine according to one of claims 5 and / or 6, in which the deep-drawn lid is attached to a transport device with the help of Drivers can be moved past the rotating pressure cylinder, characterized in that that the adapted to a part of the outer circumference of the raised edge of the lid Driver (10) are provided with outwardly protruding recesses (27) which the to be printed outer surfaces (8) of the cover (12) correspond.