Method for printing a cylindrical printing surface of a beverage can, and printed beverage can

Abstract

The invention relates to a method for printing a cylindrical printing surface of a beverage can with a printing image, and to a beverage can. The method comprises a first and a second printing operation, in the first printing operation, a first section of the printing surface being printed by way of a first printing process in a first printing press, in the second printing operation, a second section of the printing surface being printed by way of a second printing process which is preferably different from the first printing process in a second printing press, the beverage can being positioned before or during the second printing operation in such a way that the second section of the printing surface is oriented in a predefined position with respect to the first section of the printing surface. The beverage can is printed by way of this method, the first section and the second section of the printing surface being arranged in a predefined position with respect to one another.

Claims

1. A method for printing an image on a cylindrical outer surface of a plurality of metallic containers in two distinct operations on independent equipment, comprising: printing, in a first printing operation, a first section of the cylindrical outer surface of each of the plurality of metallic containers with a first portion of the image by a relief printing process in a first printing press at a first site; printing, by the relief printing process in the first printing press during the first printing operation, a distinct second section of the cylindrical outer surface of each of the plurality of metallic containers with a uniform color, wherein the first and second sections adjoin one another without overlapping; removing the plurality of metallic containers from the first printing press; applying an internal coating to the plurality of metallic containers at the first site after the first printing operation and before palletizing the plurality of metallic containers; forming a flange adapted to receive an end closure by drawing in an open end of each of the plurality of metallic containers, wherein the flange is formed at the first site after the first printing operation; palletizing the plurality of flanged metallic containers; transporting a pallet including the plurality of flanged metallic containers from the first site to a second site that is different than the first site; removing the plurality of flanged metallic containers from the pallet at the second site; loading the plurality of flanged metallic containers into a second printing press at the second site; detecting a position of the first portion of the image on each of the plurality of flanged metallic containers; orienting each of the plurality of flanged metallic containers with respect to the second printing press in such a way that a second portion of the image to be applied to the distinct second section of the cylindrical outer surface is oriented relative to the first portion of the image in the first section of the cylindrical outer surface; and printing, in a second printing operation, the distinct second section of the cylindrical outer surface with the second portion of the image by a digital printing process in the second printing press, wherein the second printing press is independent of the first printing press and located at the second site.

2. The method of claim 1, wherein each of the plurality of metallic containers is manufactured from aluminum or tin, and wherein the digital printing process is operable to process metallic containers with diameters of between 40 and 90 mm, and heights of between 40 and 250 mm.

3. The method of claim 1, wherein the second portion of the image which is applied to the distinct second section of the cylindrical outer surface is oriented with an accuracy of approximately 50 micrometers relative to the first portion of the image which is applied to the first section of the cylindrical outer surface, and wherein the second printing press prints the second portion of the image at about 600 DPI.

4. The method of claim 1, wherein the first section is of rectangular configuration and the distinct second section is arranged at least partially within the first section and is of rectangular, square, circular or oval configuration, the first section having a recess which corresponds substantially to the second section.

5. The method of claim 1, wherein loading the plurality of flanged metallic containers into the second printing press includes positioning the flanged metallic containers on mandrels of the second printing press, and wherein the second printing press prints flanged metallic containers with drawn in open ends.

6. The method of claim 1, further comprising: printing a register mark by the first printing press; and detecting the register mark by a sensor of the second printing press.

7. The method of claim 1, wherein the second printing operation takes place independently of the first printing operation.

8. The method of claim 1, wherein the first and second sections have sizes that are either substantially the same or one section is larger than the other section, the smaller section being up to 10% of the larger section.

9. The method of claim 1, wherein the internal coating is applied to the plurality of metallic containers before the flange is formed on the plurality of metallic containers.

10. The method of claim 1, wherein the internal coating is applied to the plurality of metallic containers by a spraying machine.

11. The method of claim 1, further comprising: drying each of the plurality of metallic containers in an oven after the first printing operation and before applying the internal coating; and drying the internal coating in an oven before the flange is formed on the plurality of metallic containers.

12. The method of claim 11, further comprising palletizing the plurality of flanged metallic containers with the first and second image portions.

13. The method of claim 1, wherein the uniform color printed by the first printing press in the distinct second section is white.

14. The method of claim 1, wherein the metallic containers are two-piece metallic containers formed by a draw-and-ironing process.

15. The method of claim 1, wherein the second section has an area that is less than approximately 30% of an area of the cylindrical outer surface of each of the plurality of metallic containers.

16. The method of claim 1, wherein the metallic containers are manufactured without a base coat.

17. A system for decorating a plurality of metallic containers with an image in two distinct printing operations by two independent printers located at two distinct sites, comprising: a first printer at a first site to print a first portion of the image in a first printing operation by a relief printing process, the first image portion printed in a first section of an exterior surface of each of the plurality of metallic containers, wherein the first printer is operable to print a second section of the exterior surface with a uniform color, the second section distinct from and not overlapping the first section; a coating device to apply an internal coating to each of the plurality of metallic containers after the first printing operation is completed, wherein the internal coating is dried before a flange is formed on each of the plurality of metallic containers; an apparatus at the first site to form the flange on an open end of each of the plurality of metallic containers after printing the first image portion in the first printing operation; a palletizer to place the plurality of flanged and coated metallic containers in a pallet at the first site after printing the first image portion in the first printing operation; a feeder to remove the plurality of flanged and coated metallic containers from the pallet at a second site, wherein the second site is geographically distinct from the first site; a mandrel that receives the plurality of flanged and coated metallic containers from the feeder; and a second printer to print a second portion of the image in the second section of the exterior surface of each of the plurality of flanged and coated metallic containers in a second printing operation by a digital printing process, wherein the mandrel orients each of the plurality of flanged and coated metallic containers with respect to the second printer such that the second image portion is registered relative to the first image portion and an outer circumference of the image is formed at least partially by the first section.

18. The system of claim 17, wherein the coating device comprises a spray machine to apply the internal coating to each of the plurality of metallic containers after the first printing operation is completed.

19. The system of claim 17, wherein the second printing operation occurs independently of the first printing operation.

20. A method of decorating a plurality of metallic containers in two distinct operations at two different locations, comprising: printing, by a first printer at a first site, a first image on a first section of an outer surface of each of the plurality of metallic containers, wherein the first printer is a relief printer; printing, by the first printer, a second section of the outer surface of each of the plurality of metallic containers with a uniform color, wherein the second section is at least partially adjacent the first section; spraying a coating onto an inner surface of each of the plurality of the metallic containers after the first printer prints the first and second sections of the plurality of metallic containers; drying the coating on the plurality of metallic containers; drawing-in open ends of the each of the plurality of metallic containers to form a flange for an end closure, wherein the flange is formed after the coating is dried; palletizing the plurality of flanged metallic containers after drawing-in the open ends; removing a first group of the plurality of flanged metallic containers from a pallet at a second site that is different from the first site; loading the first group of flanged metallic containers into a second printer at the second site; detecting a position of each of the first group of flanged metallic containers with respect to the second printer; orienting each of the first group of flanged metallic containers to align the second section in a predetermined orientation with respect to the second printer; and printing, with the second printer, a second image on the second section of each of the first group of flanged metallic containers, wherein the second printer is a digital printer.

21. The method of claim 20, further comprising: removing a second group of the plurality of flanged metallic containers from a pallet; loading the second group of flanged metallic containers into the second printer; detecting a position of each of the second group of flanged metallic containers with respect to the second printer; orienting each of the second group of flanged metallic containers to align the second section in a predetermined orientation with respect to the second printer; and printing, with the second printer, a third image on the second section of each of the second group of flanged metallic containers.

22. The method of claim 20, wherein orienting the second section with respect to the second printer comprises a sensor detecting the first image on each of the first group of flanged metallic containers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Preferred embodiments of the invention will be described by way of example using the appended figures, in which:

(2) FIG. 1 shows a diagrammatic flow diagram of a manufacturing process for beverage cans with a first embodiment of a method according to the invention,

(3) FIG. 2 shows a diagrammatic flow diagram of a manufacturing process for beverage cans with a second embodiment of a method according to the invention,

(4) FIG. 3 shows a first example for a printing image which is composed from two sections,

(5) FIG. 4 shows a second example for a printing image which is composed from two sections,

(6) FIG. 5 shows a third example for a printing image which is composed from two sections, and

(7) FIG. 6 shows a fourth example for a printing image which is composed from two sections.

DETAILED DESCRIPTION

(8) FIG. 1 shows a process for manufacturing beverage cans in steps 1 to 19. In step 1, a blank is punched out and is deep-drawn to form a bowl which is elongated in step 2 and the open end of which is cut or trimmed in step 3. In step 4, excess elongation agent is washed off from the beverage cans and the cans are dried in an oven, before they are provided with a first outer coat (step 5), for example with a white coat. Subsequently, the beverage cans are fed to an oven for drying in step 6. In a printing press, the beverage cans are then printed using the relief printing process in step 7 and are subsequently dried in an oven in step 8. After a first inner coat by means of a paint spraying machine in step 9 and subsequent drying in an oven in step 10, the open ends of the beverage cans are drawn in in step 11 and are provided with a flange edge before the bottoms of the beverage cans are painted in a bottom painting machine in step 12. The bottom painting is required, in particular, in the case of beverage cans made from tin.

(9) After a second inner coat, in particular in the case of beverage cans made from tin, in a paint spraying machine in step 13, the beverage cans are again dried in an oven in step 14 before they are inspected in step 15 and are provided in step 16 with a further bottom coating, for example a UV coating. In step 17, sorting of the beverage cans can take place using defined sorting markings before the beverage cans are palletized in step 18, possibly according to item type, and are fed to a store in step 19.

(10) After an undefined or predefined storage time or storage time on demand, the beverage cans can be removed from the pallet again in step 20 and can be printed digitally in a step 21 and can subsequently be dried in an oven in step 22. The performance only of steps 1 to 19 corresponds to the standard relief printing process, if the entire printing image is printed using the relief printing process in step 7. The performance of steps 1 to 6, 21, 22 and 9 to 19 according to the arrows B corresponds to the conventional process of complete digital printing, that is to say production of the entire printing image using the digital printing process.

(11) The performance of the steps 1 to 8, 18 to 22 and subsequently steps 9 to 20 according to the arrows A corresponds to one embodiment of the method according to the invention, in which, in step 7, only a first section of the printing image is printed using the relief printing process in a first printing press by means of a first printing process. After drying in step 8, the partially printed beverage cans are guided past the processing steps 9 to 17 in a bypass and are integrated again into the manufacturing process in step 18. After palletization in step 18 and storage in the palletized state in step 19, the beverage cans are subsequently removed from the pallets in step 20, are fed to a digital printing press for printing the second section using the digital printing process in step 21 and, after drying in step 22, are fed again to the usual manufacturing process after step 8 and are mixed with the beverage cans which are printed using the relief printing process. These beverage cans which are then also printed in the second printing operation then pass through steps 9 to 16 which have not been passed through before from inner coating to UV bottom coating. After decorative pattern detection and corresponding separation in step 17, the beverage cans are palletized in each case separately. In step 17, the digitally printed beverage cans are preferably separated from the beverage cans printed using the relief printing process and are palletized in step 20. The beverage cans printed using the relief printing process run further onto the line palletizer and are palletized there in step 18.

(12) This method according to FIG. 1 has the advantage of realizing both a pure relief printing process, a pure digital printing process and an embodiment of a method according to the invention with a combination of relief printing and digital printing. Furthermore, merely a digital printing station for step 21 and an oven for step 22, and possibly a pallet removing device for step 20, are to be provided additionally in an existing plant for producing beverage cans. In this way, an existing plant for producing beverage cans can be retrofitted simply for carrying out a method according to the invention.

(13) FIG. 2 likewise shows in steps 101 to 114 a customary manufacturing process of a beverage can with punching out of a blank and deep drawing of a bowl in step 101, elongation in step 102 and subsequent trimming of the open end in step 103. After excess elongation agent has been washed off in step 104, the beverage cans are dried in step 105 and are subsequently provided with a UV coating in step 106, before printing using the relief printing process takes place in step 107 with subsequent drying in step 108. A coat is subsequently applied in step 109 by way of a paint spraying machine, which coat is subsequently dried in step 110. In step 111, the open end of the beverage cans is drawn in and is provided with a flange edge. After the inspection of the beverage cans in step 112, they are palletized in a palletizing device in step 113 and are subsequently stored according to step 114. After an undefined or predefined storage time or storage on demand, the beverage cans are removed from the pallets and are fed to one or more parallel digital printing presses. In the exemplary embodiment which is shown in FIG. 2, four digital printing presses are provided, with the result that beverage cans can be printed digitally in parallel in steps 116a, b, c, d. The beverage cans are subsequently dried together in step 117 and are palletized again in step 118. The provision of a plurality of digital printing presses in step 116a, b, c, d has the advantage that a higher throughput can be achieved, for example 200 million beverage cans annually.

(14) The variant which is shown in FIG. 2 has the advantage that the beverage cans do not once again have to be inserted into the manufacturing process after the second printing operation, but rather the second printing operation can take place independently of the first printing operation and further steps of the manufacturing process. The second printing operation can therefore also advantageously take place independently of the material of the beverage can, that is to say tin or aluminum. Furthermore, different can diameters, different can heights and beverage cans which are already drawn in at the open end can preferably be printed digitally in the second printing operation.

(15) Moreover, the fundamental advantages of the method according to the invention with the division of the printing of the first and second section by way of first and second printing presses can also be realized with the exemplary embodiment which is shown in FIG. 2.

(16) FIGS. 3 to 6 show examples for printing images which are composed from two sections. The printing images are shown as rectangles of the laid flat cylindrical printing surface. In the examples, the areas of the two sections together in each case form the rectangle of the laid flat cylindrical printing surface, that is to say printing images which fill the rectangle of the laid flat cylindrical printing surface are produced overall.

(17) In FIG. 3, the first section 210 and the second section 220 are equally large and form two halves of the rectangle of the laid flat cylindrical printing surface. In FIG. 4, the second section 221 is of square configuration and is arranged in a correspondingly square recess in a corner of the first section 211. FIG. 5 shows the configuration of the second section 222 as an oval which is arranged in a corresponding recess in a central region of the first section 212. In FIG. 6, the second section 223 is of rectangular configuration and is arranged in a corresponding recess at the lower edge of the first section 213.

(18) The illustrations of FIGS. 3 to 6 can also be realized with a reversed configuration of the sections, that is to say the shapes of the second sections which are shown can also be formed by the first sections and vice versa.

(19) Furthermore, in each case one configuration, in which the two sections adjoin one another without overlapping, is shown in the examples of FIGS. 3 to 6 which are shown. It can be preferred, however, that the printing image of one section protrudes into an adjoining overlapping region of the other section. It is particularly preferred, in particular in the case of complex printing images, that both sections protrude in each case into an adjoining overlapping region of the respectively other section.