WO2024099560A1

WO2024099560A1 - Label feeding system with double sensor monitoring unit

Info

Publication number: WO2024099560A1
Application number: PCT/EP2022/081392
Authority: WO
Inventors: Marco Ferri; Cristian ANDREATO
Original assignee: Sidel Participations
Priority date: 2022-11-10
Filing date: 2022-11-10
Publication date: 2024-05-16

Abstract

A label feeding system for a labelling machine comprising - a feed roller (24) for longitudinally feeding a web of labelling material, the web comprising a plurality of longitudinally joined labels each of which comprises a mark (8) and a reference region (9); - a monitoring unit (30) for monitoring the web (4) being fed, defining a monitoring station which is preferably positioned downstream of the feed roller (24) with respect to the feeding direction, and comprising: - a mark reader (31), for reading the mark (8) of each label being positioned in the monitoring station, the mark reader (8) being configured for working with a reading frequency which is correlated to a production speed of the labelling machine (1); - an optical sensor (32), for optically check at least a respective portion (P) of each label being positioned in the monitoring station.

Description

LABEL FEEDING SYSTEM WITH DOUBLE SENSOR MONITORING UNIT TECHNICAL FIELD The present invention relates to a label feeding system for a labelling machine, and to a labelling machine comprising the labels feeding system. BACKGROUND ART In the field of labelling machines, there is the need of feeding the web of labelling material to a separating unit which is configured for separating sequentially the labels from the web. The separating activity of the separation unit shall be as much correct as possible. Therefore, there is the need of regulating the feeding as a function of parameters like the actual longitudinal length of the labels, which can be different from the nominal value. To this end, typically a mark reader is used, which operates in an on/off manner with a preestablished time window which opens with a frequency which is typically correlated to the production speed of the labelling machine. It can occur that a false mark is read, which can cause problems because the subsequent management and regulation will be as a function of this false mark. DISCLOSURE OF INVENTION A label feeding system according to any of the system claims or according to present description is configured for obtaining a more accurate regulation of the feeding. A labelling machine according to any of the appended machine claims or according to present description comprises a feeding system according to any of the appended system claims or according to present description. The following detailed description is referred to respective possible embodiments of a feeding system and a labelling machine according to present description, which will be named for simplicity as “system” and “machine”. BRIEF DESCRIPTION OF THE DRAWINGS The machine and the system will be described with reference to the appended drawings in which: Figure 1 is a schematic top view of the machine; Figure 2 is a view showing a sector of a web which can be fed by means of the system, and some components of the system; and Figure 3 is an enlarged view of a label of the web of Figure 2. BEST MODES FOR CARRYING OUT THE INVENTION The machine 1 comprises the system 13. The machine 1 is for labelling container 3 by means of labels 2. The system 13 comprises a feed roller 24 for longitudinally feeding a web 4 of labelling material. The web 4 comprises a plurality of longitudinally joined labels each of which comprises a mark 8 and a reference region 9. A longitudinal sector of the web 4 is shown on Figure 2. The system 13 comprises a monitoring unit 30 for monitoring the web 4 being fed. The monitoring unit 30 defines a monitoring station 33, which is preferably positioned downstream of the feed roller 24 with respect to the feeding direction. A sector of the web 4 is shown in Figure 2. In Figure 2, arrow A indicates the direction of feeding. The system 13 comprises a mark reader 31, for reading the mark 8 of each label being positioned in the monitoring station 33. The mark reader 8 is configured for working with a reading frequency which is correlated to a production speed of the machine 1. The system 13 comprises an optical sensor 32, for optically check a portion P of each label 2 being positioned in the monitoring station 33, to detect at least the presence or absence of the reference region 9 within the checked portion P. The sensor 32 works with a checking frequency which is correlated to the reading frequency, so that for each reading, the optical sensor 32 performs an associated check. The system 13 is preferably configured so that the checked portion P is fixed with respect to the frame on which the feeding system 13 is mounted, in the sense that the position of the checked portion P with respect to said frame is fixed. The mark reader 31 and the optical sensor 32 are preferably fixed with respect to the frame. The system 13 comprises an automatic control unit. The system 13, by means of the control unit, is configured for automatically determining the correctness of each reading, based on the respective check. The system 13, by means of the control unit, is configured for automatically determining the correctness of each reading based at least on said presence or absence. Practically, the mark reader 31 carries out a reading activity, for monitoring the feeding of the web 4, while the sensor 32 carries out a detection activity, for detecting possible errors in the reading activity, and therefore for monitoring the reading activity. In this way, an error of the reading can be determined, so that for example a user can be informed and an appropriate action can be taken, reducing the risk of wasting material of the web. In fact, an incorrect reading can lead to an incorrect application of labels on containers 3. In particular, an incorrect reading can occur following an operation of splicing between a web in use and a new web. The system 13 is configured, by means of the control unit and based on the detection activity of the sensor 32, for automatically alerting a user about at least one error of the reading activity of the mark reader 31. The mark reader 31 is a cheap device for monitoring the feeding of the web 4. Therefore, present invention allows to improve the reliability of a cheap label feeding system which allows for automatically controlling the feeding of the web of labelling material based on monitoring the actual length of the label. The system 13 is configured so that each check is automatically triggered by the associated reading. The system 13 is configured so that said mark reader 31 works with said reading frequency in an on-off manner with a preestablished time window. This kind of mark reader 31 can be considered very cheap. The time window opens with the reading frequency, in the sense that the mark reader 31 is switched on with the reading frequency. For each opening of the time window, the mark reader 31 is switched off, and therefore the time window is closed, after a certain time interval has elapsed after the switching on. This time interval can be predetermined. The system 13, by means of the control unit, is configured for automatically determining the correctness of each reading based at least on a detected distance d between said reference region 9 and said mark 8. The distance d is schematically shown in Figure 3. Therefore, the accuracy of the detection activity is improved. The system 13, by means of the control unit, is configured so that, for each reading, the optical sensor 32 performs the associated check with a time offset with respect to the associated reading. In this way the detection activity can be preliminary set to improve the accuracy of this detection activity as a function of the specific features of the label 2, to improve the flexibility of the feeding system 13. The system, by means of the control unit, is configured so that the feed roller 24 is automatically controlled as a function of the readings. In particular, the feeding speed is automatically controlled based on a quantity correlated to the actual length of the labels, said quantity being obtained based on said readings. The system 13, by means of the control unit, is configured so that said time offset is automatically determined by the time trend of the amount of web 4 being fed, so that each check occurs after a preestablished longitudinal amount of web 4 is fed after the respective associated reading. In this way, the detection activity is automatically regulated and varied as a function of the actual feeding speed, to maintain the same level of accuracy upon variation of the feeding speed. In this way, the accuracy and/or flexibility of the feeding system are furtherly improved. Alternatively, the time offset is preestablished. The optical sensor 32 is a second reader and the reference region is a second mark, to furtherly reduce the costs. Alternatively, the optical sensor is a camera or fotocamera and the reference region 9 corresponds to a specific aesthetical pattern. In this case, the accuracy of detection activity is improved. In this connection, each check can correspond to the acquisition of at least one respective image by the camera or fotocamera. The portion P can correspond to the field of vision of the camera or fotocamera. The distance d can be an expected distance between the detected mark 8 and the reference region 9 of the same label 2, in the sense that if the difference between the actual value and the expected value is too high, an error can be detected. For example, it can be that a splicing operation of a first web with a second web has been performed incorrectly. For this reason, the reference region 9 may not be placed at the expected distance d from the detected mark 8, or can be absent. In this case, the detected mark 8 does not correspond to a false mark 8, but an error is anyway detected, indicating an erroneous splicing operation. In this case, the error is an error of the feeding, which means an error related to the feeding of the web, which in turn derives from an incorrect splicing operation. The system 13 comprises a separation unit 15 for sequentially separating the labels from the web 4, downstream of the feed roller 24. The separation unit 15 is configured for working with a separation frequency correlated or corresponding to the production speed of the labelling machine 1, the reading frequency being correlated to the separation frequency. The separation unit 15 can be a cutting unit 15 which is configured for separating the labels by cutting sequentially the web. The separation frequency can be correlated for example to the angular speed of a cutting roller 23. The cutting roller 23 can carry a blade 21. The system 13 is configured, by mans of the control unit, for automatically informing a user about the level of correctness of the reading activity. The system 13 is configured, by mans of the control unit, for automatically alerting a user about at least one error of said reading activity. The machine 1 comprises a transfer drum 17 for sequentially receiving the labels from the separating unit 15 and sequentially applying the labels on respective containers 2. Alternatively, the transfer drum 17 is configured for receiving the web and sequentially applying the labels 2 on respective containers 3. In this case the cutting unit 15 would be configured for cutting sequentially the web while the web is transported by the drum 17. The machine 1 comprises a conveyor 10 for conveying the containers 3, and is configured so that the containers 3 are labelled while being conveyed. The system 13 comprises a storage unit 26 for storing a reel of web. The feed roller 24 feeds the web by unwinding the web 4 off the reel. The machine 1 comprises a gluing roller 18 for applying glue on each label 2. Clearly, changes may be made to machine or system without, however, departing from the scope of protection as defined in the accompanying claims.

Claims

CLAIMS 1. A label feeding system (13) for a labelling machine (1) comprising: - a feed roller (24) for longitudinally feeding a web (4) of labelling material, the web (4) comprising a plurality of longitudinally joined labels (2), each of which comprises a mark (8) and a reference region (9); - a monitoring unit (30) for monitoring the web (4) being fed, defining a monitoring station (33) which is preferably positioned downstream of the feed roller (24) with respect to the feeding direction, and comprising: - a mark reader (31), for reading the mark (8) of each label being positioned in the monitoring station (33), the mark reader (31) being configured for working with a reading frequency which is correlated to a production speed of the labelling machine (1); - an optical sensor (32), for optically check at least a respective portion (P) of each label being positioned in the monitoring station (33), to detect at least the presence or absence of the reference region (9) within the checked portion (P), the sensor (32) working with a checking frequency which is correlated to the reading frequency, so that for each reading the optical sensor performs an associated check. 2. Feeding system (13) according to Claim 1, wherein the system (13) is configured for automatically determining the correctness of each reading based on the respective check. 3. Feeding system (13) according to Claim 1 or 2, wherein the system is configured for automatically determining the correctness of each reading based at least on said presence or absence. 4. Feeding system (13) according to any of the previous Claims, wherein the system (13) is configured for automatically determining the correctness of each reading based at least on a detected distance (d) between said reference region (9) and said mark (8). 5. Feeding system according to any of the Previous Claims, wherein the system is configured so that, for each reading, the optical sensor (32) performs the associated check with a time offset with respect to the reading. 6. Feeding system according to Claim 5, wherein the system (13) is configured so that said time offset is automatically determined by the time trend of the amount of web being fed, so that each check occurs after a preestablished amount of web is fed after the respective associated reading. 7. Feeding system according to Claim 5 or 6, wherein the time offset is preestablished. 8. Feeding system (13) according to any of the previous Claims, wherein the system is configured so that each check is automatically triggered by the associated reading. 9. Feeding system (13) according to any of the previous claims, wherein the system (13) is configured so that said mark reader (31) works with said reading frequency in an on- off manner with a preestablished time window. 10. Feeding system (13) according to any of the previous claims, wherein the system (13) is configured so that the feeding speed is automatically controlled based on a quantity correlated to the actual length of the labels, and for obtaining said quantity based on said readings. 11. System (13) according to any of the previous claims, wherein the system (13) is configured, based on the detection activity of the sensor (32), for automatically alerting a user about at least one error of the reading activity of the mark reader (31) or an error of the feeding. 12. Feeding system (13) according to any of the previous claims, wherein the optical sensor (32) is a second reader and the reference region is a second mark. 13. Feeding system according to any of Claims from 1 to 11, wherein the optical sensor (32) is a camera or fotocamera and the reference region (9) corresponds to a specific aesthetical pattern, the portion (P) preferably corresponding to the field of vision of the camera or fotocamera and being preferably fixed with respect to a frame of the feeding system (13), the camera or fotocamera being preferably fixed with respect to said frame. 14. Feeding system (13) according to any of the previous Claims, comprising a separation unit (15) for sequentially separating the labels from the web (4), downstream of the feed roller (24), the separation unit (15) being configured for working with a separation frequency correlated or corresponding to said production speed, the reading frequency being correlated to the separation frequency. 15. Feeding system (13) according to Claim 14, wherein the separation unit (15) is a cutting unit (15) which is configured for separating the labels by cutting sequentially the web. 16. Labelling machine for labelling containers (2), comprising a feeding system (13) according to any of the previous Claims. 17. Labelling machine (1) according to Claim 16, wherein: - the feeding system (13) is according to Claim 15; - the labelling machine (1) comprises a transfer drum (17) for sequentially receiving the separated labels from the cutting unit (15) and sequentially applying the labels on respective containers (2). 18. Labelling machine (1) according to Claim 16, wherein: - the feeding system (13) is according to Claim 15; - the labelling machine (1) comprises a transfer drum (17) for receiving the web and sequentially applying the labels (2) on respective containers (3), the cutting unit (15) being configured for cutting sequentially the web while the web is transported by the drum (17).