Method for aligning a strip of labels

Abstract

A method for aligning a strip of labels, which contains a plurality of labels, relative to a cutting device, wherein the strip of labels is cut into labels by the cutting device that are subsequently applied to containers. In a learning mode, the strip of labels is automatically transported by a transport device and the position of the strip of labels relative to the cutting device is detected by a position sensor disposed as a first camera, and, in an aligning mode, an operator can then enter a desired cutting parameter in a machine control unit of an input unit. Information indicated of the desired cutting parameter relative to the strip of labels is then displayed to the operator on a screen, and the machine control unit controls the cutting device on the basis of the desired cutting parameter.

Claims

1. A method for aligning a strip of labels having a plurality of labels relative to a cutting device, wherein the strip of labels is cut into labels by the cutting device that are subsequently applied to containers, in a learning mode, automatically transporting the strip of labels by a transport device, and detecting the position of the strip of labels relative to the cutting device by means of a position sensor embodied as a first camera, evaluating a camera image of the position sensor representing the strip of labels with a first image-processing unit, automatically detecting an actual cutting parameter for the cutting device providing a suggested cutting position relative to the strip of labels, and then in an aligning mode, displaying on a screen the camera image of the position sensor representing the strip of labels, displaying information indicative of the actual cutting parameter on the screen relative to the strip of labels, permitting an operator to enter a desired cutting parameter in a machine control unit by means of an input unit, displaying the desired cutting parameter as a line relative to the camera image representing the strip of labels to the operator on the screen, and controlling, via the machine control unit, the cutting device on the basis of the desired cutting parameter.

2. The method according to claim 1, and storing the desired cutting parameter in a database.

3. The method according to claim 1, and storing the actual cutting parameter in a database.

4. The method according to claim 1, and, then in a quality assurance mode, detecting the cut strip of labels via a quality assurance unit embodied as a second camera.

5. The method according to claim 4, and the quality assurance unit automatically detecting a cutting position at the cut strip of labels with the aid of a second image-processing unit and displaying information indicative of the cutting position on the screen relative to the cut strip of labels.

6. The method according to claim 5, and, then in a correction mode, the machine control unit automatically correcting a deviation of the desired cutting parameter from the cutting position.

7. The method according to claim 5, and storing the cutting position in a database.

8. A labeling machine for labeling containers, comprising: a transport device for transporting a strip of labels with a plurality of labels, a cutting unit for cutting the strip of labels, a position sensor embodied as a first camera for detecting the position of the strip of labels relative to the cutting unit, a machine control unit with a screen and an input unit, the input unit is embodied to at least one of enter or correct a desired cutting parameter, the screen is embodied to display a camera image of the position sensor representing the strip of labels and the desired cutting parameter as a line relative to the camera image representing the strip of labels, and a cutting position of the cutting unit is controllable by the machine control unit on the basis of the desired cutting parameter, a quality assurance unit for detecting the cut strip of labels, wherein the quality assurance unit comprises a second camera, and an image processing unit embodied to evaluate a cutting position from a camera image of the cut strip of labels.

9. The labeling machine according to claim 8, further comprising a first image-processing unit for evaluating the position of the strip of labels from a camera image of the position sensor, and wherein the image processing unit comprises a second image processing unit.

10. The labeling machine according to claim 9, wherein the first image-processing unit is embodied to detect transformation-invariant features of the plurality of labels.

11. The labeling machine according to claim 9, wherein the first image-processing unit is embodied to compare the camera image with a reference image.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 shows a labeling machine according to the invention in a plan view;

(2) FIG. 2 shows a screen display of the strip of labels when the desired cutting parameter is entered with an input unit;

(3) FIG. 3 shows a screen display during an automatic detection of the actual cutting parameter; and

(4) FIG. 4 shows a screen display after the detection of the cutting position by a quality assurance unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) FIG. 1 shows a labeling machine 1 according to the invention in a plan view. One can see that the strip of labels 2a is passed through the various units of the labeling machine 1 by the transport device 3. In the process, the strip of labels 2a is first passed by the position sensor 5 and cut into individual labels at the cutting device 4. Subsequently, the individual labels 2c are passed by the gluing station 17 and attached to containers with the transfer roller 18 (not represented here).

(6) The transport device 3 comprises a supply roller 3d, a conglutination station 3c for conglutinating the strip of labels 2a at the occasion of a change of the supply roller 3d, a belt buffer 3b and several deflection rollers 3a. The transport device 3 guides and transports further the strip of labels 2a within the labeling machine 1.

(7) The cutting device 4 comprises a vacuum roller 4a and a cutting tool 4b. Here, the initially uncut strip of labels 2a is fed to the cutting device 4 and fixed on the vacuum roller 4a by means of a vacuum. The cutting tool 4b has a plurality of vertically extending blades by which the strip of labels 2a may be cut into the individual labels 2c. The cutting device 4 is embodied to be controllable such that the cutting position may be varied along the direction of transport of the strip of labels 2a. Thereby, the cutting device 4 may be adapted to different label lengths such that the cutting position extends at the provided edges of the labels 2c.

(8) However, since the position of the strip of labels 2a relative to the cutting device 4 is not known from the beginning, it is detected by the position sensor 5 which is disposed upstream of the cutting device 4. One can see that the position sensor 5 is embodied as a first camera and oriented with a perpendicular angle of view onto the strip of labels 2a. The field of view of the position sensor 5 detects a length of the strip of labels 2a which is larger than one individual label 2c. The images of the position sensor 5 are now transmitted to the first image-processing unit 12a via an image data line 19 and evaluated there. The first image-processing unit 12a is here integrally arranged in the machine control unit 6. As an alternative, it may also be arranged within the position sensor 5.

(9) The first image-processing unit 12a is here embodied on the strip of labels 2a to detect characteristic features of the label print. For example, the edges of an individual label print are detected, and their positions relative to the position sensor 5 are determined. Moreover, in the position sensor 5, its distance to the cutting device 4 is stored. For example, this distance is the path of the strip of labels 2a in the conveying direction starting from the image's center of the camera image to a reference cutting position in the cutting device 4. This distance is once calibrated at the occasion of the commissioning of the labeling machine 1 and stored as a parameter, together with the width of the camera image in the plane of the strip of labels 2a, in the position sensor 5 or in the machine control unit 6. Consequently, the distance of a certain column in the camera image to the reference cutting position of the cutting device 4 may be calculated via these parameters. As described above, the position of the label edge is already detected by the first image-processing unit 12a, and the position of the strip of labels relative to the cutting device 4 may thus be directly calculated.

(10) In the learning mode, the transport device 3 automatically passes the strip of labels 2a by the position sensor 5, and by the above-described procedure, the position of the strip of labels 2a relative to the cutting device 4 is automatically detected. The machine control unit 6 with the first image-processing unit 12a and the control module 14 for controlling the cutting device 4 takes care of the automatic control.

(11) Subsequently, the camera image of the position sensor 5 is displayed on the screen 8 in the aligning mode. On the screen 8, the image of the strip of labels 2a, an automatically determined actual cutting parameter 10, and the desired cutting parameter 9 selected by the operator can be seen. This desired cutting parameter 9 may be entered or corrected by the operator through the input unit 7. This is illustrated in FIGS. 2-4 below.

(12) Moreover, the quality assurance unit 16 is arranged in the region of the ejection of the cutting device 4. It is embodied as a second camera and detects the cut strip of labels 2b with its angle of view. The camera image is transmitted to the second image-processing unit 12b via the image data line 21. With the second image-processing unit 12b, the cutting position is automatically determined in the image of the cut strip of labels 2b. As indicated in FIG. 4, a correction of the desired cutting parameter may be effected in a correction mode thereby. Moreover, the operator may visually assess whether the cutting position is correctly selected.

(13) Subsequently, the cut labels 2c are attached to containers (not shown here).

(14) With the labeling machine 1 according to the invention, it is easily and quickly possible to teach a new type of label with the position sensor 5 and to predetermine the correct position of the desired cutting parameter for controlling the cutting device 4. It is equally possible to automatically correct, via the quality assurance unit 16 in the correction mode, a deviation of the desired cutting parameter 9 from the actual cutting position. With this information, a calibration of the distance of the position sensor 5 from the cutting device 4 may also be effected.

(15) Moreover, the data determined in the method (e. g. actual and desired cutting parameters, cutting position and/or image data) are stored in the database 15 by the machine control unit 6. Thereby, a label type does not have to be taught again, calibration parameters may be stored, and the data may be consulted for later evaluation.

(16) FIG. 2 shows a screen display of the strip of labels 2a during the entering of the desired cutting parameter 9 with the input unit 7.

(17) On the screen 8, the image of the strip of labels 2a is represented which was taken with the first camera of the position sensor 5 of FIG. 1. The strip of labels 2a has several labels 2c with the represented prints. Moreover, the desired cutting parameter 9 is shown. It may be horizontally shifted along the double arrow with the input unit 7 via the arrow keys 7a and 7b and confirmed with the key 7c.

(18) Thus, in the aligning mode, the desired cutting parameter 9 relative to the strip of labels 2a is displayed. The operator may now enter the desired cutting parameter 9 into the machine control unit 6 with the input unit 7 (cf. FIG. 1). Here, the operator may shift the desired cutting parameter 9 along the strip of labels with the arrow keys 7a and 7b such that it corresponds to the desired cutting position.

(19) Subsequently, the machine control unit 6 may control the cutting device 4 via the control module 14 such that the cut is performed corresponding to the desired cutting parameter 9.

(20) FIG. 3 shows a screen display during an automatic detection of the actual cutting parameter 10. It is automatically determined by the first image-processing unit 12a from the camera image of the position sensor 5 in the learning mode. For example, this is the edge of the label print or the center between two subsequent edges. Thereby, the operator is assisted in entering the desired cutting parameter 9 as quickly as possible.

(21) One can see here that the actual cutting parameter 10 was calculated to be too far on the left side, and consequently, the operator may shift the actual cutting parameter 10 via the arrow keys 7a and 7b such that the desired cutting parameter 9 is reached. The actual cutting parameter 10 and the desired cutting parameter 9 may be represented in different colors and/or line types on the screen 8.

(22) FIG. 4 shows a screen display after the detection of the cutting position 13 by the quality assurance unit 16. As was described with reference to FIG. 1, the quality assurance unit 16 automatically detects the cutting position 13 at the cut strip of labels 2c. This information is now represented on the screen 8 with respect to the yet uncut strip of labels 2a.

(23) One can see that a distance A between the desired cutting parameter and the cutting position 13 results. This may be explained, for example, by a faulty calibration of the distance of the position sensor 5 to the cutting device 4, or by a maladjusted cutting device 4.

(24) In the correction mode, the machine control unit 6 may now calculate and automatically correct the deviation of the desired cutting parameter 9 from the cutting position 13. By this, the corresponding calibration parameters in the machine control unit 6 may also be corrected. As an alternative, the operator may also manually correct the position of the desired cutting parameter 9 via the arrow keys 7a and 7b and moreover determine the deviation A in the correction mode.

(25) The above-mentioned calibrations, parameters, camera images, actual cutting parameters and desired cutting parameters may be stored in the database 15 to retrieve the data at a later point in time and correspondingly evaluate them.

(26) It will be understood that features mentioned in the above described embodiments are not restricted to these special combinations and are possible in any other combinations.