EP4053028A1

EP4053028A1 - Labelling machine and method for applying labels onto articles adapted to contain a pourable product

Info

Publication number: EP4053028A1
Application number: EP21160857.5A
Authority: EP
Inventors: Nicola Veneziani
Original assignee: Sidel Participations SAS
Current assignee: Sidel Participations SAS
Priority date: 2021-03-05
Filing date: 2021-03-05
Publication date: 2022-09-07

Abstract

A labelling machine (1) comprising: a conveyor (4) for advancing a plurality of articles (2) to be labelled along a labelling path (P); a labelling module (5) comprising a label distributor (8) arranged at the receiving station (R) and configured to receive one label storage member (6) at a time containing a pre-determined number of labels (3) and a label transfer device (11, 12) configured to sequentially withdraw the labels (3) from the distributor (8) and to feed the labels (3) to the conveyor (4) for the application thereof onto the respective articles (2) at the application station (A); a work surface (16) arranged peripherally to the labelling module (5); a plurality of conveying members (17) movable onto and along the work surface (16) by a magnetic-inductive interaction device (18, 19) and each configured to carry one label storage member (6) at a time.

Description

TECHNICAL FIELD

The present invention relates to a labelling machine for applying labels onto articles, in particular containers, such as bottles, cans, jars, or the like, adapted to contain a pourable product, preferably a pourable food product.
The present invention also relates to a method for applying labels onto articles, in particular containers, such as bottles, cans, jars, or the like, adapted to contain a pourable product, preferably a pourable food product.

BACKGROUND ART

Labelling machines are known, which are commonly used to prepare, transport and apply labels onto articles, in particular containers such as bottles, cans, jars or the like, destined to be filled with a pourable product, in particular a pourable food product.
A labelling machine of the known type typically comprises:

a rotary carousel, rotatable around a vertical axis and configured to convey a plurality of articles along an horizontal, arc-shaped transfer path;
an input station, at which the articles to be labelled are received by the carousel;
an output station, at which the labelled articles exit the carousel; and
one or more labelling modules, each peripherally arranged relatively to the carousel and configured to feed a plurality of labels to the carousel itself at an application station, in order to apply such labels to respective articles.

Particularly widespread is the use of glued labels, i.e. portions of a labelling material that are cut at appropriate lengths from a web of labelling material initially wound around one or more storage reels and then sprinkled with glue.
In detail, the web of labelling material is unwound off the relative reel and then sequentially cut in successive labels of equal length, upon which glue is applied by gluing means, such as a gluing roller, spray or injector systems or the like.
Eventually, the labels so obtained are conveyed and applied onto the respective articles to be labelled.
Another known type of glued labels are pre-cut labels which are initially stored in label loaders, or cartridges, containing a pre-determined amount of pre-cut labels. Such pre-cut labels are sequentially withdrawn from the cartridge, one at a time, in order to be sprinkled with glue and then applied to the respective articles.
According to this latter configuration, the labelling module typically comprises:

a label distributor configured to receive, at a receiving station, at least one label loader or cartridge at a time containing a number of pre-cut labels; and
a label transfer device configured to successively withdraw labels from the distributor and to feed such labels to the carousel for the application thereof on the respective articles at an application station.

In detail, the label transfer device comprises:

a glue roller covered with glue and rotatable about a first axis;
a first rotor rotatable about a second axis and comprising a plurality of paddles configured to subsequently and cyclically cooperate with the glue roller so as to be covered with glue and to pick successive labels from the distributor; and
a second rotor rotatable about a third axis and comprising a plurality of hooks which receive, in use, respective labels with glue thereon from the first rotor and convey such labels towards the carousel, in order to apply such labels onto respective containers at the application station.

Although being functionally valid, the labelling machines of the above-mentioned type are open to further improvements.
In fact, as soon as the cartridge is empty, i.e. all the pre-cut labels contained therein have been withdrawn by the transfer device and applied onto the relative articles, the cartridge has to be substituted with a new cartridge full of pre-cut labels.
This operation requires a stop of the labelling machine, which often causes the insurgence of large downtimes for the cartridge change.
This problem is even more accentuated in the case of label format change, particularly when a label format change is necessary for labelling the same article, i.e. when the same article has to be labelled with a first type of label and then with a second type of label. Usually, such situation requires either a rather time-consuming format change or applying the second labels to the articles via a second labelling machine.
The above drawbacks are even more accentuated in the case in which labelling machine comprises two or more labelling modules, since a change of cartridge and/ or a format change has to be performed for each one of them.

DISCLOSURE OF INVENTION

It is therefore an object of the present invention to provide a labelling machine which is designed to overcome at least one of the above-mentioned drawbacks in a straightforward and low-cost manner.
This object is achieved by a labelling machine as claimed in claim 1.
It is a further object of the present invention to provide a method for applying labels onto articles which is designed to overcome at least one of the above-mentioned drawbacks in a straightforward and low-cost manner.
This object is achieved by a method for applying labels onto articles as claimed in claim 13.

BRIEF DESCRIPTION OF THE DRAWINGS

A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:

Figure 1 is a schematic top view, with parts removed for clarity, of a labelling machine according to the present invention;
Figure 2 is an enlarged-scale, schematic top view, with parts removed for clarity, of a part of the labelling machine of Figure 1 during a particular moment of the operation thereof; and
Figure 3 is an enlarged-scale, partially sectioned, lateral view, with parts removed for clarity, of a detail of the labelling machine of Figure 1.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to Figures 1 and 2, number 1 indicates as a whole a labelling machine configured to apply labels 3 onto articles 2, in particular containers such as bottles, cans, jars, or the like, adapted to contain a pourable product, preferably a pourable food product.
According to this non-limiting embodiment shown, labels 3 applied by labelling machine 1 are glued labels, i.e. strips of labelling material which are cut at predetermined lengths and to which glue is applied according to a manner that will be described in the following.
As visible in Figure 1, labelling machine 1 essentially comprises:

a conveyor device, preferably a rotary carousel 4 rotatable around a fixed axis, in particular a vertical axis Z, and configured to advance a plurality of articles 2 along a labelling path P, in particular an arc-shaped, horizontal path;
an input station I, at which articles 2 to be labelled are fed to carousel 4;
an output station O, at which labelled articles 2 exit from carousel 4; and
one or more labelling modules 5 (two in the example shown); each of the modules 5 is arranged peripherally relatively to carousel 4 and the machine 1 is configured so that each module 5 feeds a plurality of labels 3 to the carousel 4 itself at a respective application station A, to apply labels 3 to respective articles 2.

In the example shown labels 3 are defined by pre-cut strips of labelling material which are initially stored in label storage members, in particular label loaders or, more in particular, label cartridges 6.
As shown in Figure 3, each cartridge 6 contains a predetermined amount of pre-cut labels 3. Such pre-cut labels 3 are, in use, sequentially withdrawn from the respective cartridge 6, one at a time, in order to be sprinkled with glue and then applied to the respective articles 2.
Preferably, each cartridge 6 comprises an outlet opening 6a (schematically shown in Figure 3) and pushing means 7 configured to exert a pushing force onto the labels 3 contained in the cartridge 6, so as to push and direct labels 3 towards outlet opening 6a and to ease the withdrawal of labels 3 off cartridge 6, as explained below.
More specifically, elastic means 7 comprise a spring 7a fixed at a back wall 6b of cartridge 6 and a pushing element 7b coupled with spring 7a. The pushing element 7b is mechanically interposed between the labels and the spring 7a. The cartridge 6 is configured so that the pushing element 7b cooperates with the label 3 of cartridge 6 most proximate to back wall 6b so as to push, due to the action of spring 7a, such label 3 towards outlet opening 6a.
For the sake of brevity, reference will be made in the following to a single labelling module 5. However, all the features hereby described in connection with labelling module 5 are equally applicable to each labelling module 5 present in labelling machine 1.
According to the preferred embodiment shown, labelling module 5 comprises:

a label distributor 8 arranged at a receiving station R of labelling module 5, and configured to receive one cartridge 6 at a time; and
a label transfer device configured to sequentially withdraw labels 3, one at a time, from distributor 8 and to feed such labels 3 to the carousel 4 for the application thereof onto the respective articles 2 at application station A.

In the example shown, the label transfer device comprises:

a glue roller 10 coverable with glue and rotatable about a first axis, preferably a vertical axis;
a first rotor 11 rotatable about a second axis, preferably a vertical axis, and comprising a plurality of paddles 12 (only schematically shown), the module 5 being configured so that each paddle 12 subsequently and cyclically cooperates with glue roller 10 so as to be covered with glue and to pick successive labels 3, which are preferably pushed in use by elastic means 7, from distributor 8; and
a second rotor 13 rotatable about a third axis, preferably a vertical axis, and comprising a plurality of hooks 14, the module 5 being configured so that the hooks 14 receive respective labels 3 with glue thereon from first rotor 11 and convey such labels 3 towards carousel 4, to apply them onto respective articles 2 at the respective application station A.

Hence, in use, each label 3, pushed by elastic means 7 within cartridge 6, is withdrawn from distributor 8 by one paddle 12 of the first rotor 11, which paddle 12 has been sprinkled with glue, and is picked by a hook 14 of second rotor 13, which applies the label 3 to a respective article 3.
To this end, each cartridge 6 has to be brought from a first position, at which cartridge 6 is away from receiving station R and, therefore, distributor 8, to a second position, at which cartridge 6 is at receiving station R and it is operatively coupled to distributor 8 for feeding labels 3 stored therein to distributor 8.
Cartridges 6 in the second position are visible in Figures 1 and 2. In use, when each cartridge 6 is empty, i.e. all the pre-cut labels 3 contained therein have been withdrawn and applied onto the relative articles 3, cartridge 6 has to be substituted with a new cartridge 6 filled with pre-cut labels 3.
To this end, labelling machine 1 further comprises:

a support structure 15 having a work surface 16 arranged peripherally to labelling module 5 and operatively couplable to labelling module 5 at receiving station R; and
a plurality of conveying members 17 operatively coupled to work surface 16, movable onto and along work surface 16 in a levitating manner, and each configured to carry at least one cartridge 6 at a time and to selectively convey such cartridge 6 to and away from receiving station R so as to selectively feed or withdraw cartridge 6 to or from distributor 8.

As visible in Figure 3, labelling machine 1 further comprises a magnetic- inductive interaction device 18, 19 between conveying members 17 and work surface 16 for imparting to conveying members 17 the levitating movement relative to work surface 16 (and support structure 15).
In particular, magnetic- inductive interaction device 18, 19 comprises individually-excitable solenoids 18 carried by work surface 16 and permanent magnets 19 carried by conveying members 17.
More in particular, individually-excitable solenoids 18 are embedded in support structure 15, in particular are embedded in an upper portion of support structure 15 proximate to work surface 16. Permanent magnets 19 are each one carried by one respective conveying member 17.
Alternatively, solenoids 18 can be carried, each, by respective conveying members 17 and permanent magnets 19 can be embedded in work surface 16.
Solenoids 18 and permanent magnets 19 are adapted to magnetically couple to one another so as to magnetically interact with one another to produce the movement and the levitation of conveying members 17 with respect to work surface 16.
In detail, each conveying member 17 levitates, in use and due to the interaction produced between the relative permanent magnet 19 and solenoids 18, onto the work surface 16, during its movement along work surface 16.
Therefore, conveying members 17 are movable in a levitating manner onto and along work surface 16.
In light of the above, labelling machine 1 comprises a planar motor unit 20 defined by work surface 16 (support structure 15), the plurality of conveying members 17 and the magnetic- inductive interaction device 18, 19.
Each conveying member 17 is defined by a levitatable cart comprising a receiving portion 17a for receiving and supporting at least one cartridge 6 at a time (as schematically shown in Figure 3). Each conveying member 17 is mechanically independent from the others.
Work surface 16 has a storage portion 21 which is configured to store a number of cartridges 6 in their first positions and an exchange portion 22 which is operatively coupled with distributor 8 at receiving station R and is configured to receive cartridges 6 in their second positions.
Each conveying member 17 is movable between a conveying/rest position, at which it is away from receiving station R and, therefore, distributor 8, and a feed position, at which it is at receiving station R and it is operatively coupled to distributor 8 for feeding labels 3 to the distributor.
More specifically, conveying members 17 in conveying/rest position are at the storage portion 21, whereas conveying members 17 in feed position are at the exchange portion 22.
In practice, in use, each conveying member 17 conveys, by its levitating movement onto and along work surface 16 imparted by magnetic- inductive interaction device 18, 19, at least one cartridge 6 at a time filled with labels 3, from storage portion 21 to exchange portion 22, i.e. towards receiving station R, at which conveying member 17 interacts with distributor 8 for feeding labels 3 thereto.
In detail, conveying member 17 feeds the cartridge 6 it is transporting to distributor 8, which receives such cartridge 6 and arranges it for label withdrawal by first roller 11.
Once cartridge 6 is empty, or almost empty, conveying member 17 is moved by magnetic- inductive interaction device 18, 19 away from receiving station R, thereby withdrawing cartridge 6 from distributor 8 and conveying it away from distributor 8 towards storage portion 21.
Conveniently, substantially at the same time, another conveying member 17 conveys a new cartridge 6 filled with labels 3 to distributor 8.
In practice, each conveying member 17 is configured to sequentially carry cartridges 6, at least one at a time, between storage portion 21 and exchange portion 22, so that the plurality of conveying members 17 determine, in use, a sequential change of cartridges 6 at distributor 8. In this way, labelling machine 1 provides for an automatic change of cartridges 6, which can be performed automatically and without the intervention of an operator.
Conveniently, an appropriate, predetermined number of filled cartridges 6 are prepared in advance by putting them onto respective conveying members 17 at storage portion 21 of work surface 16.
Where labelling machine 1 comprises two or more labelling modules 5, as in the example shown, such labelling modules 5 are arranged peripherally to carousel 4 at respective application stations A (Figures 1 and 2). Accordingly, work surface 16 is operatively coupled to each labelling module 5 at the respective receiving station R. In this case, conveying members 17 are configured to selectively convey at least one cartridge 6 at a time to or away from the relative labelling module 5 at the respective receiving station R, so as to feed or withdraw such at least one cartridge 6 to or from the respective distributor 8.
In detail, work surface 16 defines a common shared change device for changing i.e. substituting cartridges 6 for each labelling module 5.
In this way, labelling machine 1 provides for the above-mentioned automatic change of cartridges 6 for each labelling module 5 present in labelling machine 1.
Conveniently, labelling machine 1 comprises a control unit (known per se and not shown).
The control unit is configured to bias the solenoids 18 with a current, so that an electromagnetic coupling is established, in use, between said solenoids 18 and said permanent magnets 19.
The control unit is configured for regulating a distribution of said current on the work surface 16 and/or with respect to said work surface 16 so as to control the movement of each conveying member 17 to and away from the receiving station R (and distributor 8). In particular the control unit is configured for regulating said distribution, for each conveying member 17, based on the position of the conveying member 17 with respect to the work surface 16. This applies in particular in the case the magnetic- inductive interaction device 18, 19 comprises individually-excitable solenoids 18 carried by work surface 16 and permanent magnets 19 carried by conveying members 17. Each conveying member 17 is movable between a conveying/rest position, at which it is away from the receiving station R, and a feed position, at which it is at the receiving station R and it is operatively coupled to the distributor 8 for feeding labels 3 to the distributor 8.
For each conveying member 17, the control unit is configured for obtaining, when the conveying member 17 adopts the feed position, a physical quantity between the conveying member 17 and the work surface 16. For each conveying member 17, the control unit is configured for correlating the obtained quantity with the amount of labels 3 present in at least one label storage member 6 being carried by the conveying member 17.
For each conveying member 17, the control unit is further configured to control a movement of the conveying member 17 from the feed position to the conveying/rest position when the obtained physical quantity reaches a predetermined value, so as to determine, in use, a sequential change of label storage members 6 at the distributor 8. The machine 1 comprises at least one sensor system. The sensor system is configured for detecting at least said quantity. The sensor system communicates with the control unit to enable the control unit to obtain the physical quantity.
In other words, the movement of conveying members 17 to and away from receiving station R, and therefore distributor 8, is controlled based upon a physical quantity.
This allows a quicker automatic change of the storage member 6.
The control unit, the planar motor unit 20, the storage members 6, the magnetic- inductive interaction device 18, 19, the work surface 16, and the conveying members 17, define an automatic storage for storing the labels to be used by the at least one labelling module 5. The automatic storage comprises the control unit, the work surface 16, the planar motor unit 20, the magnetic- inductive interaction device 18, 19, the storage members 6, and the conveying members 17. The automatic change of the storage members 6 can be considered an automatic storage function.
According to a first embodiment, for each conveying member 17, the control unit is configured for obtaining, when the conveying member 17 adopts the feed position, the current needed to maintain the conveying member 17 at a predetermined vertical distance from the work surface 16. "Vertical distance" means a distance along a vertical direction which is transversal or orthogonal with respect to the work surface 16. The predetermined vertical distance can correspond to the operative distance occurring during the labelling operation. For each conveying member 17, the control unit is configured for correlating the obtained needed current with the amount of labels 3 present in at least one label storage member 6 being carried by the conveying member 17.
For each conveying member 17, the control unit is further configured for automatically controlling a movement of the conveying member 17 from the feed position to the conveying/rest position when the obtained needed current reaches a predetermined value, for example when the needed current falls below a given threshold current value. According to this first embodiment, the physical quantity corresponds to the needed current.
In fact, the weight of each cartridge 6 in the second position decreases during the labelling operation, due to the fact that less labels 3 are contained therein.
Accordingly, less current is needed to maintain the respective conveying member 17 at the same predetermined distance from work surface 16.
In this first embodiment, the sensor system comprises at least one current sensor, or at least one current sensor and at least one distance sensor.
The first embodiment allows a simple setting of the control unit for enabling the automatic storage to carry out the automatic storage function.
Each conveying member 17 comprises a receiving portion 17a for receiving and carrying at least one label storage member 6 at a time. According to a second embodiment, the receiving portion 17a is provided with a load cell configured to detect a load exerted thereon by at least one label storage member 6 being carried by the conveying member 17.
For each conveying member 17, the control unit is configured for obtaining, when the conveying member 17 adopts the feed position, the load exerted on the load cell by the at least one label storage member 6 being carried by the conveying member 17. For each conveying member 17, the control unit is configured for correlating the obtained load with the amount of labels 3 present in said at least one label storage member 6 being carried by the conveying member 17.
For each conveying member 17, the control unit is further configured for automatically controlling a movement of the respective conveying member 17 from the feed position to the conveying/rest position when the obtained load reaches a predetermined value. According to this second embodiment, the physical quantity corresponds to the load.
In fact, the weight of each cartridge 6 in the second position decreases during the labelling operation, due to the fact that less labels 3 are contained therein.
In this second embodiment, the sensor system comprises at least said load cell.
This second embodiment allows the automatic storage function to be less affected by possible vibrations.
According to a third embodiment, for each conveying member 17, the control unit is configured for obtaining, when the conveying member 17 adopts the feed position, a vertical distance of the conveying member 17 relative to the work surface 16, for a given current biased to the solenoids to keep the conveying member 17 levitating. For each conveying member 17, the control unit is configured for correlating the obtained distance with the amount of labels 3 present in said at least one label storage member 6 being carried by the conveying member 17.
For each conveying member 17, the control unit is further configured to control a movement of the conveying member 17 from the feed position to the conveying/rest position when the obtained distance reaches a predetermined value.According to this third embodiment, the physical quantity corresponds to the distance. In this connection, the current biased by the control unit to the solenoids 18 is to be considered always the same given current, whereas the vertical distance between the conveying member 17 and the work surface 16 can vary, i.e. can increase due to the decreasing weight of cartridge 6.
In this third embodiment, the sensor system comprises at least one distance sensor, or at least one current sensor and at least one distance sensor.
The third embodiment allows for a very precise detection of the amount of labels 3 present in the storage member 6.
Preferably, distributor 8 comprises a buffer portion (not shown) adapted for storing a predetermined number of labels 3.
Conveniently, in use, during the labelling operation, a non-zero number of labels 3 is stored into the buffer portion, between a movement of a first conveying member 17 away from distributor 8 and a movement of a second conveying member 17 to distributor 8, so as to ensure the continuity of the labelling operation when cartridges 6 have to be substituted.
The advantages of labelling machine 1 according to the present invention will be clear from the foregoing description.
In particular, thanks to the above configuration, frequent stops of labelling machine 1 are avoided, since the change of cartridges 6 can occur in a fully automated mode. In fact, it is sufficient to prepare the desired amount of cartridges 6 and to put them in the storage portion 21 on respective conveying members 17.
Furthermore, an undetermined number of new cartridges 6 can be provided on empty conveying members 17 during the operation of labelling machine 1, since conveying members 17 are substantially free to move along work surface 16 and, therefore, they can be controlled as not to hinder the movement of one another.
Conversely, in the known art, fixed transversal conveyors of cartridges 6 are known, for which labelling machine 1 has to be stopped when a recharge is due.
Moreover, the present invention is particularly advantageous in case a label format change is necessary. In fact, in such a case it is sufficient to provide cartridges 6 containing labels of a new format onto respective conveying members 17 and this operation can be done during the labelling operation, without the need for stopping labelling machine 1.
Hence, flexibility of labelling machine 1 is improved.
In addition, due to the fact that conveying members 17 are movable along work surface 16 in a levitating manner, overall wear is strongly reduced, thereby resulting in a decreased need for maintenance and in a reduction of overall costs.
Clearly, changes may be made to labelling machine 1 as described herein without, however, departing from the scope of protection as defined in the accompanying claims.
In particular, the present invention could also be implemented in labelling machines operating with other types of glued labels, such as labels obtained from a web of labelling material initially wound in storage reels. In this case, the label storage members are defined by reels of labelling material in the form of a continuous web and labelling modules comprise unwinding rollers, a cutting device, a glue roller and a vacuum drum.
Also, in this case conveying members 17 are configured to convey the reels of labelling material from the storage portion 21 to the exchange portion 22.

Claims

A labelling machine (1) configured to apply labels (3) onto articles (2) adapted to contain a pourable product, the labelling machine (1) comprising:
- a conveyor (4) for advancing a plurality of articles (2) to be labelled along a labelling path (P); and

- at least one labelling module (5) arranged peripherally to the conveyor (4) and having a receiving station (R) and an application station (A);
the labelling module (5) comprising:
- a label distributor (8) arranged at the receiving station (R) and configured to receive at least one label storage member (6) at a time containing a pre-determined number of labels (3); and

- a label transfer device (11, 12) configured to sequentially withdraw the labels (3) from the distributor (8) and to feed the labels (3) to the conveyor (4) for the application thereof onto the respective articles (2) at the application station (A);
the labelling machine (1) further comprising:
- a work surface (16) arranged peripherally to the labelling module (5) and operatively couplable to the labelling module (5) at said receiving station (R);

- a plurality of conveying members (17) operatively coupled to the work surface (16), movable onto and along the work surface (16) in a levitating manner, and each configured to carry at least one label storage member (6) at a time and to selectively convey such at least one label storage member (6) to and away from the receiving station (R) so as to selectively feed or withdraw the label storage member (6) to or from the distributor (8); and

- a magnetic-inductive interaction device (18, 19) between the conveying members (17) and the work surface (16) for imparting to the conveying members (17) the levitating movement relative to the work surface (16).
Labelling machine as claimed in claim 1, and comprising a planar motor unit (20) defined by the work surface (16), the plurality of conveying members (17) and the magnetic-inductive interaction device (18, 19).
Labelling machine as claimed in claim 1 or 2, wherein the work surface (16) has a storage portion (21) which is configured to store a number of label storage members (6), and an exchange portion (22) which is operatively coupled with the distributor (8), at the receiving station (R);
and wherein each conveying member (17) is configured to sequentially carry at least one storage member (6), between the storage portion (21) and the exchange portion (22), so that the plurality of conveying members (17) determine, in use, a sequential change of label storage members (6) at the distributor (8).
Labelling machine as claimed in any one of the foregoing claims, wherein the magnetic-inductive interaction device (18, 19) comprises individually-excitable solenoids (18) carried by one of the work surface (16) and the conveying members (17) and permanent magnets (19) carried by the other of the conveying members (17) and the work surface (16).
Labelling machine as claimed in claim 4, and comprising a control unit configured to bias the solenoids (18) with a current, so that an electromagnetic coupling is established, in use, between said solenoids (18) and said permanent magnets (19);
wherein the control unit is configured for regulating a distribution of said current on said work surface (16) so as to control the movement of each conveying member (17) to and away from the receiving station (R).
Labelling machine as claimed in claim 5, wherein each conveying member (17) is movable between a conveying/rest position, at which it is away from the receiving station (R), and a feed position, at which it is at the receiving station (R) and it is operatively coupled to the distributor (8) for feeding labels (3) to the distributor (8);
wherein, for each conveying member (17):
the control unit is configured for obtaining, when the conveying member (17) adopts the feed position, a physical quantity between the conveying member (17) and the work surface (16), to correlate the detected quantity with the amount of labels (3) present in at least one label storage member (6) being carried by the conveying member (17);

the control unit is further configured to control a movement of the conveying member (17) from the feed position to the conveying/rest position when the obtained physical quantity reaches a predetermined value, so as to determine, in use, a sequential change of label storage members (6) at the distributor (8).
Labelling machine as claimed in claim 6, wherein, for each conveying member (17):
the control unit is configured for obtaining, when the conveying member (17) adopts the feed position, the current needed to maintain the conveying member (17) at a predetermined vertical distance from the work surface (16), to correlate the obtained needed current with the amount of labels (3) present in at least one label storage member (6) being carried by the conveying member (17);

the control unit is further configured for automatically controlling a movement of the conveying member (17) from the feed position to the conveying/rest position when the obtained needed current reaches a predetermined value.
Labelling machine as claimed in claim 6, wherein, for each conveying member (17):
the conveying member (17) comprises a receiving portion (17a) for receiving and carrying at least one label storage member (6) at a time, the receiving portion (17a) being provided with at least one load cell configured to detect a load exerted thereon by said at least one label storage member (6) being carried by the conveying member (17);

the control unit is configured for obtaining, when the conveying member (17) adopts the feed position, the load exerted on the load cell by said at least one label storage member (6) being carried by the conveying member (17), to correlate the obtained load with the amount of labels (3) present in said at least one label storage member (6) being carried by the conveying member (17);

the control unit is further configured for automatically controlling a movement of the respective conveying member (7) from the feed position to the conveying/rest position when the obtained load reaches a predetermined value.
Labelling machine as claimed in claim 6, wherein, for each conveying member (17):
the control unit is configured for obtaining, when the conveying member (17) adopts the feed position and for a given current biased to the solenoids to keep the conveying member (17) levitating, a vertical distance of the conveying member (17) relative to the work surface (16), to correlate the obtained distance with the amount of labels (3) present in at least one label storage member (6) being carried by the conveying member (17);

the control unit is further configured to control a movement of the conveying member (17) from the feed position to the conveying/rest position when the obtained distance reaches a predetermined value.
Labelling machine as claimed in any one of the foregoing claims, wherein the label transfer device comprises:
- a glue roller (10) coverable with glue and rotatable about a first axis;

- a first rotor (11) rotatable about a second axis and comprising a plurality of paddles (12) configured to subsequently and cyclically cooperate with the glue roller (10) so as to be covered with glue and to pick successive labels (3) from the distributor (8); and

- a second rotor (13) rotatable about a third axis and comprising a plurality of hooks (14) configured to receive respective labels (3) with glue thereon from the first rotor (11) and to convey such labels (3) towards the conveyor (4), in order to apply such labels (2) onto respective articles (2) at the application station (A).
Labelling machine as claimed in claim 10, wherein the label storage member (6) comprises a cartridge (6) configured to store a predetermined number of pre-cut labels (3), the cartridge (6) having an outlet opening (6a) through which the first rotor (11) is configured to pick the labels (3) off the cartridge (6).
Labelling machine as claimed in any one of the foregoing claims, and comprising at least two said labelling modules (5) arranged peripherally to the conveyor (4);
wherein the work surface (16) is operatively coupled to each labelling module (5) at the respective receiving station (R);
and wherein the conveying members (17) are configured to selectively convey at least one label storage member (6) at a time to or away from each labelling module (5) at the respective receiving station (R), so as to feed or withdraw the label storage member (6) to or from the respective distributor (8).
Method for applying labels (3) onto articles (2) adapted to contain a pourable product, the method comprising the steps of:
a) advancing a plurality of articles (2) to be labelled along a labelling path (P);

b) withdrawing a sequence of labels (3) from a label distributor (8);

c) applying the withdrawn labels (3) to said articles (2) ;

d) feeding one label storage member (6) at a time containing a predetermined number of labels (3) to said distributor (8);

e) withdrawing the label storage member (6) from the distributor (8);

f) arranging a plurality of conveying members (17) on a work surface (16) which is operatively couplable to the distributor (8), each conveying member (17) carrying one label storage member (6) at a time;

g) moving the conveying members (17) onto and along the work surface (16) in a levitating manner at a non-zero distance therefrom by means of a magnetic-inductive interaction between the conveying members (17) and the work surface (16);
wherein the steps d) of feeding and e) of withdrawing are carried out by means of the step g) of moving.
Method as claimed in claim 13, and further comprising the step of:
h) detecting a physical quantity between the conveying members (17) and the work surface (16);
wherein the steps d) of feeding and e) of withdrawing are carried out when the detected physical quantity reaches a predetermined value.
Method as claimed in claim 13 or 14, wherein the distributor (8) has a buffer portion for storing a predetermined number of labels (3); and wherein the method further comprises the step of:
i) storing a non-zero number of labels (3) into the buffer portion between a movement of a first conveying member (17) away from the distributor (8) and a movement of a second conveying member (17) to the distributor (8).