METHOD AND DEVICE FOR PRODUCING PARTIALLY EMBOSSED BLANKS

Abstract

A method for producing partially embossed blanks is disclosed. The method is to provide a continuous web of an embossable material, and guide it between two cylinders which emboss its surface. The embossed web is fed to a stamping device to punch blanks from the web. One of the embossing cylinders has a marking which is readable by a first sensor. The first sensor reads the position of the marking and produces a signal which triggers a printing device to produce a print mark on the web identifying the position of the embossing. The print mark is read by a second sensor which produces a signal for controlling and adjusting a feeding distance by which feed rolls supply the web to the stamping device that punches blanks from the web in register with the partial embossing of the blank. A device for conducting the method is also disclosed.

Claims

1. A method for producing partially embossed blanks, each partially embossed blank having an embossed and a non-embossed area, the method comprising the steps of: providing a continuous web of an embossable material; guiding said web between two embossing cylinders; partially embossing the surface of the web between the two embossing cylinders; supplying the embossed web to a stamping device at which the blanks are punched from the web; wherein one of the embossing cylinders comprises a marking, said marking being readable by a first sensor, said first sensor reading the position of the marking and producing a signal, said signal triggering a printing device, said printing device producing a print mark on the web after the embossing step thereby identifying the position of the embossing, feeding the embossed and marked web, driven by at least one feed rolls, to a stamping device, said print mark being read by a second sensor, said second sensor producing a signal for controlling and adjusting a feeding distance D by which the at least one feed rolls supplies the embossed and marked web to the stamping device for punching the partially embossed blanks from the web at a predefined position in register with the partial embossing of the blank.

2. A method according to claim 1, wherein the printing device is an ink jet printing device.

3. A method according to claim 1, wherein the print mark is printed in the form of a pattern.

4. A method according to claim 3, wherein the print mark comprises at least a line.

5. A method according to claim 3, wherein the print mark comprises at least a dot.

6. A method according to claim 3, wherein the print mark comprises at least one graphical element selected from the group consisting of lines, dots, circles, triangles and rectangles.

7. A device for producing partially embossed blanks, the device comprising a continuous web of an embossable material, a guiding device for guiding the web, two embossing cylinders for embossing the surface of the web between the two embossing cylinders wherein one of the embossing cylinders comprises a marking, a feeder device for supplying the embossed web to a stamping device the stamping device for punching the blanks from the web, a first sensor for reading the position of said marking and producing a signal, a computer for processing said signal to trigger a printing device for producing a print mark on the web after the embossing process, a second sensor for identifying the position of the embossing, a stamping device fed with the embossed and marked web by the at least one feed rolls, the second sensor also for reading said print mark and for producing a signal for controlling and adjusting a feeding distance D by which the at least one feed rolls supplies the embossed and marked web to the stamping device for punching the partially embossed blanks from the web at a predefined position in register with the partial embossing of the blank.

8. A device according to claim 7, wherein the printing device is an ink jet printing device.

9. A method according to claim 2, wherein the print mark is printed in the form of a pattern.

Description

[0027] The method for producing partially embossed blanks according to the present invention is explained in more detail below with reference to an exemplary embodiment in the FIG. 1, in which, purely schematically:

[0028] FIG. 1 shows an embodiment of the device.

[0029] FIG. 2A shows a first embodiment of a partially embossed blank;

[0030] FIG. 2B shows a second embodiment of a partially embossed blank;

[0031] FIG. 2C shows a third embodiment of a partially embossed blank.

[0032] As a non-limiting example, a method is illustrated and device for producing single, partially embossed blanks 20 according to the present invention is shown in FIG. 1.

[0033] In FIG. 1 is shown a reel or coil 1 containing a continuous or endless web 4 of an embossable material, means like a motor for unwinding the web 4, motor driven embossing cylinders, namely an embossing roller or embossing cylinder 2 and a backing roll or counter pressure embossing cylinder 3, as well as downstream means like rolls 8, 9, 10, 11, 12 for guiding the web 4 in direction of a pair of motor driven feeder rolls 14, 15 and a punching device 68.

[0034] In order to adjust the feeding speed of the web 4 in the unwinding station (not shown) to the speed of the web 4 during the embossing process step, the rotational speed of reel 1 can be decelerated, what means the unwinding station comprises a brake mechanism. The embossing roller 2 and the backing roll 3, i.e. the counter pressure cylinder, serve as means for embossing a part of the free lying surface of web 4 between said motor driven embossing cylinders 2, 3. One of the embossing cylinders, here embossing roller 2, comprises a marking 30 in the form of an indentation or an elevation worked in the embossing cylinder 2. The device further comprises an inkjet print head 40 for producing an inkjet marking 50, i.e. a print mark, on web 4 after the embossing process. All inkjet markings are provided on the same border area of the web 4. The inkjet print mark 50 may be eyemarkings, or may have the form of a dot or a thin stripe or other forms and patterns. Eyemarks are small rectangular printing areas located at or near the edge of a web. The discharge of ink by the inkjet print head 40 is triggered by a signal of a sensor 35 when marking 30 of embossing roller 2 passes sensor 35. Inkjet markings 50 on web 4 are used to identify the position of the embossing. The contour 23 of each partially embossed blank 20 on web 4 is shown for illustration purposes only. The contour or outer rim 23 of the blank 20 is defined by the stamp 60 and the die plate 65 of the stamping device 68, i.e. the outer rim 23 is formed when the blank 20 is punched out from the web 4 by the stamping device 68.

[0035] The embossing cylinders 2, 3 form the partial embossing into the web 4. The partial embossing comprises a plain area 26 and an embossed area 27. The outer contour or outer rim 23 is depicted only to better illustrate the plain area 26 of the blank 20. For example, as illustrated in FIGS. 2A and 2C, if the partially embossed blank 20 is intended for use as a lid to be sealed on the rim of a cup, the plain area 26 forms an endless rim for sealing to the cup, and the embossed area 27 is surrounded by the rim.

[0036] The continuous web 4 with the consecutively arranged embossed areas 27 of the partially embossed blanks 20 progresses towards a punching device 68 comprising a stamp 60 and a die plate 65. The travelling web 4 is supported and guided by rollers 8, 9, 10, 11, 12. The web part between rollers 10 and 11 is free hanging and serves to compensate the different process speeds of the embossing and the punching processes, especially in regard to the continuous embossing process whereas the punching process is a sequential stepwise process.

[0037] A second sensor 55 recognizes print marks 50 each belonging to an embossed area 27 of a partially embossed blank 20 on web 4 and defining the position of the partially embossed blank, respectively of the partial embossing on the web.

[0038] The print mark 50 reading sensor 55 controls and adjusts a feeding distance D by which the feed rolls (14, 15) supply the embossed and marked web (4) to the stamping device (68) for punching the partially embossed blanks (20) from the web (4) at a predefined position in register with the partial embossing.

[0039] Alternatively, the print mark 50 reading sensor 55 triggers the speed of feeder rolls 14, 15 and the activation of the punch stroke of punching device 68. Hence, triggered by the signal from second sensor 55, feeder rollers 14, 15 adjust the feed rate of the web 4 in direction of the punching device 68 and simultaneously the signal from the second sensor 55 adjusts the cycle of the punch stroke. By adjusting the feed rate of web 4 and the cycle of the punch stroke, based on the signal when print mark 50 passes the second sensor 55, the die cut tool or stamp of the punching device 68 punches out the blank 20 from the web 4 exactly at a predefined position in register with the partial embossing of the blank 20.

[0040] FIG. 2A shows a first embodiment of a partially embossed blank 20. The embossed area 27 comprises quadratic structures arranged in the form of a circle near the contour or outer rim 23 of the blank 20. Apart from the embossed area 27 of the blank 20 the remaining area 26, i.e., the central part and the rim region of the blank 20, are not embossed.

[0041] In FIG. 2B a second embodiment of a partially embossed blank 20 is shown. In this embodiment the plain area 26 is arranged in the form of a rectangle in the center of the blank 20 while the remaining area of the blank 20 is embossed area 27. This means that the embossing extends to the contour or outer rim 23 of the blank 20.

[0042] FIG. 2C shows a third embodiment of a partially embossed blank 20. The embossed area 27 is arranged in the form of a circle on the blank 20. A rectangular area in the center of the blank 20 as well as the region between the embossed area 27 and the contour or outer rim 23 is plain area 26.