EP3760551A1

EP3760551A1 - Method for applying labels onto articles adapted to contain a pourable product

Info

Publication number: EP3760551A1
Application number: EP20179441.9A
Authority: EP
Inventors: Andrea MAESTRI
Original assignee: Sidel Participations SAS
Current assignee: Sidel Participations SAS
Priority date: 2019-07-05
Filing date: 2020-06-11
Publication date: 2021-01-06
Also published as: IT201900011022A1

Abstract

The invention relates to a method for applying labels (2) onto articles (3; 3a, 3b) adapted to contain a pourable product, comprising the steps of: feeding a plurality of articles (3; 3a, 3b) along a feed path (P) by a conveyor device (6); rotating the articles (3; 3a, 3b) about respective axes thereof during at least part of the feeding step; feeding at least two respective successions of labels (2) to the conveyor device (6) by at least two labelling modules (10a, 10b; 10'); conveying the two successions of labels (2) from respective receiving stations (R) to respective application stations (A), where the labels (2) are applied onto respective articles (3; 3a, 3b) by respective transfer devices (14; 17), each of which is carried by a corresponding labelling module (10a, 10b; 10'); feeding the successions of labels (2) to the corresponding transfer devices (14; 17) at the respective receiving stations (R) by respective feeding devices (15; 18), each of which is carried by a corresponding labelling module (10a, 10b; 10'); and detecting a non-nominal operating condition in one (10a; 10') of the labelling modules (10a, 10b; 10'); wherein, in the case in which, during the detection step, the non-nominal operating condition is detected in one (10a; 10') of the labelling modules (10a, 10b; 10'), the method further comprises the steps of: stopping said one (10a; 10') of the labelling modules (10a, 10b; 10'); increasing the speed of the feeding device (15; 18) of the other one (10b; 10') of the labelling modules (10a, 10b; 10'); increasing the speed of the transfer device (14; 17) of the other one (10b; 10') of the labelling modules (10a, 10b; 10'); and increasing the speed of rotation about axes thereof of the articles (3; 3a, 3b) conveyed by the conveyor device (6).

Description

TECHNICAL FIELD

The present invention relates to a method for applying labels onto articles, in particular to containers adapted to contain a pourable product, preferably a pourable food product.
In particular, the method referred to above is adapted to be implemented by a labelling machine configured to apply a plurality of labels onto respective articles of the aforesaid type.

BACKGROUND ART

Labelling machines are known which are commonly used for preparing, conveying, and applying labels onto articles, in particular containers such as bottles, tins, flasks, or the like, adapted to contain, and therefore to be filled with, a pourable product, preferably a pourable food product.
Particularly widespread is the use of "glued labels", i.e. labels obtained starting from a web of labelling material initially wound on one or more storage reels.
In detail, the above web is cut into portions of the same size, on which glue is applied. The glue is applied via gluing means, for example rolls, spraying systems, injection systems, or the like. The labels thus obtained are then transferred and glued on the outer lateral surface of respective articles.
Another type of labelling that is particularly widespread contemplates the formation of tubular labels, known as "sleeve labels", obtained starting from a web of heat-shrinking film initially wound on one or more storage reels. Such sleeve labels are applied with a certain play on the respective articles and then heated in an oven to obtain shrinking thereof and perfect adhesion to the lateral surfaces of the articles themselves. This type of label does not envisage use of glue.
Irrespective of the type of label used, a labelling machine typically comprises:

a carousel ratatable about a vertical axis and configured to convey a plurality of successive articles along a horizontal arc-shaped feed path;
an input station, at which the articles to be labelled are supplied to the carousel;
an output station, at which the articles previously labelled leave the carousel; and
at least a labelling module, arranged peripherally with respect to the carousel and configured to supply a plurality of labels to the carousel itself at an application station, and to apply, in this way, said labels onto the respective articles.

Generally, a labelling module of a known type comprises:

one or more storage units, normally rotatable rolls, around which are fixed corresponding reels of the type described above, i.e. carrying labelling material in the form of a continuous web wound around a central hub;
a plurality of winding rolls that support, in use, the web wound off the reel and guide it along a feed path;
a blade configured to cut, at a cutting station, a sequence of individual labels of the same length from the web of labelling material; and
a vacuum drum for transfer of the labels, configured to receive, hold, and advance each label previously cut, and to feed said label to the carousel at the application station.

In detail, the vacuum drum is configured to receive the labels previously cut at a receiving station and, after rotation through a given angle about the axis thereof, to release said labels to the application station so that they may be applied onto the respective articles.
As it is known, the vacuum drum receives, holds, and releases each label via suction obtained by a vacuum source.
In the case of labels that envisage the use of glue, the labelling module further comprises at least a gluing device, for example a gluing roll, arranged substantially tangential to the vacuum drum and configured to spread at least the ends of each individual label with glue.
Conveniently, the carousel, the vacuum drum, the gluing roll, and the winding rolls are synchronised in phase so as to carry out the entire labelling process properly.
In the sector of labelling machines configured to label articles containing pourable products, it is known to use two or more labelling modules of the type described above, each of which is configured to feed a respective plurality of labels to the carousel.
Generally, the two or more labelling modules are configured to:

apply respective pluralities of labels of the same format to corresponding pluralities of articles of the same format; or
each apply a respective plurality of labels of a format different from the format of the labels applied by the other module/modules to a corresponding plurality of articles of a format equal to or different from the format of the articles labelled by the other module/modules.

The possibility, during the labelling process, of one of the labelling modules being in non-nominal operating conditions is known, for example due to a failure that has arisen during the process itself.
Upon occurrence of the above eventuality, typically one of the following procedures is carried out:

the labelling machine, and therefore the labelling process, is stopped; the module that has undergone failure is temporarily deactivated (disabled), and the labelling machine is reactivated; simultaneously, maintenance work is carried out on the failed module, while the articles that should have been labelled by said failed module are discarded; once the module has been rendered operative again, the labelling machine is stopped, the repaired module is activated (enabled), and the labelling machine is reactivated; or
the labelling machine is stopped, and therefore also the labelling process until the failed module is again rendered operative.

The need is felt in the industry to limit as far as possible any stoppage of the labelling machine, the consequent interruption of the labelling process, and the discard of articles and labelling material.

DISCLOSURE OF THE INVENTION

It is therefore an aboject of the present invention to provide a method for applying labels onto articles adapted to contain a pourable product, which which is designed to meet at least one of the above-mentioned needs in a straightforward and low-cost manner.
According to the invention, the above object is achieved by a method for applying labels onto articles as claimed in claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS

Three non-limiting embodiments 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 configured to implement the method for applying labels according to the present invention;
Figure 2 is a larger-scale schematic top view, with parts removed for clarity, of a labelling module of the labelling machine of Figure 1;
Figure 3 is a larger-scale schematic top view, and with parts removed for clarity, of an alternative embodiment of the labelling module of the labelling machine of Figure 1; and
Figure 4 is a schematic top view, with parts removed for clarity, of a further embodiment of the labelling machine of Figure 1.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to Figure 1, designated as a whole by 1 is a labelling machine configured to apply, during a labelling process, labels 2 onto articles 3, in particular containers such as bottles, tins, flasks or the like, adapted to contain a pourable product, preferably a pourable food product.
Preferably, the labels 2 applied by the machine 1 are of the type known as "glue labels", i.e. labels obtained starting from a web 4 of labelling material initially wound on one or more storage reels 5.
In detail, the web 4 is cut into portions of the same size, on which glue is subsequently applied, according to a manner described hereinafter.
According to an alternative embodiment not shown, the machine 1 applies labels of the type commonly known as "sleeve labels", i.e., tubular labels obtained starting from a web of heat-shrinking film wound on one or more reels (not illustrated). Said tubular labels are applied with a certain play on the respective articles 3 and then heated in an oven to obtain their shrinkage and perfect adhesion to the lateral surfaces of the articles 3 themselves.
As may be seen in Figure 1, the machine 1 basically comprises:

a carousel 6, rotatable about a vertical axis Z and configured to convey a plurality of successive articles 3 along a horizontal arc-shaped path P;
an input conveyor, for example an input star wheel 7, configured to supply the articles 3 to the carousel 6 at an input station I;
an output conveyor, for example an output star wheel 8, configured to receive from the carousel 6 the labelled articles at the output station O; and
at least two labelling modules 10a, 10b, arranged peripherally with respect to the carousel 6 and configured to respectively supply two successions of labels 2 to the carousel 6 itself and apply them sequentially to the articles 3, at respective application stations A.

In detail, the labelling module 10a is arranged upstream of the labelling module 10b, according to the direction of advancement of the articles 3 along the path P, and is configured to apply a respective first succession of labels 2 onto first articles 3; likewise, the labelling module 10b is configured to apply a respective second succession of labels 2 onto second articles 3.
According to the above preferred embodiment, the labels 2 of the first and second successions have the same format, i.e. they are substantially identical. Likewise, the first and second articles 3 have the same format, i.e. they are substantially identical.
More precisely, the star wheel 7 feeds the first and second articles 3 to the carousel 6 in an alternating manner.
In other words, along the path P a first article 3 is always followed by a second article 3 and preceded by a further second article 3.
As may be seen in Figure 2, each labelling module 10a, 10b comprises (only the module 10b is illustrated in Figure 2) :

at least one shaft 9, which supports in a rotatable manner, in use, at least one of the aforesaid reels 5 from which the web 4 is wound off;
a plurality of winding rolls 11, which support, in use, the web 4 wound off the reel 5 and guide it along a feed path;
a cutting device, for example a blade 12, configured to separate, in particular to cut, sequentially each label 2 from the web 4 at a cutting station T, to thus obtain a respective sequence of labels 2 having the same length;
at least a gluing roll 13, adapted to spread sequentially with glue each individual label 2 previously cut by the blade 12;
a transfer device, in particular a vacuum drum 14 for transfer of the labels 2, which is mounted rotatably about an axis X, is positioned peripherally with respect to the carousel 6, preferably substantially tangential to each article 3 at the application station A, and is configured to receive and advance each label 2 previously cut and to apply it onto a respective article 3 at the application station A; and
a feeding device, preferably a feeding roll 15, rotatable about an axis Y and configured to receive the web 4 of labelling material from the reels 5 and feed it to the winding rolls 11 and, therefore, in the form of a corresponding sequence of labels 2 cut by the blade 12, to the drum 14 at a receiving station R.

In practice, the drum 14 sequentially receives, in use, the labels 2 previously cut by the blade 12 at the receiving station R, holds the labels 2 on a lateral surface 14a thereof and, after rotation through a given angle about the axis X, releases said labels 2, feeding them to the carousel 6 and transferring them to the respective articles 3 at the application station A, according to a manner known and not described in detail.
More precisely, the drum 14 holds the labels 2 on, and releases them from, the lateral surface 14a thereof via suction created by a vacuum source (not illustrated).
In order to enable application of the labels 2 onto the articles 3, the latter are rotatable about the axes thereof parallel to the axis Z of the carousel 6 during at least part of their advancement from the input station I to the output station O.
In particular, the carousel 6 comprises a plurality of plates 16, each of which inferiorly supports, in use, a respective article 3. Said plates 16 are mounted on the carousel in a rotatable manner about the axes thereof, so as to control a rotation of the articles 3 thereon.
Due to the rotation imparted by the plates 16 on the articles 3, the labels 2 that are attached to the articles 3 that reach the application station A are wound around the outer lateral surface of the articles 3 themselves. Rotation continues at least until transfer of the labels 2 is completed.
In light of the above, each labelling module 10a, 10b is configured to: feed the corresponding succession of labels 2 to the respective drum 14 by the respective feeding roll 15; convey said succession from the receiving station R thereof to the application station A thereof by the respective drum 14; and supply said succession of labels 2 to the carousel 6 and apply each label to a corresponding first article or second article 3.
There is known in the sector the possibility, during the labelling process, of a non-nominal operating condition arising for one of the labelling modules 10a, 10b, for example a failure that prevents proper and nominal operation thereof.
For this purpose, the machine 1 preferably comprises means for detecting a non-nominal operating condition in one of the labelling modules 10a, 10b, for example a control unit (not illustrated) configured to detect said non-nominal operating condition during the labelling process.
In the ensuing description, the aforementioned one of the two labelling modules 10a, 10b for which the non-nominal operating condition arises will be considered as being the labelling module 10a, without this implying any loss of generality.
For instance, during the labelling process, the labelling module 10a undergoes a failure (of whatever sort) that affects nominal operation thereof.
More precisely, the other of the two modules, i.e., the labelling module 10b is, instead, in the nominal operating conditions.
Alternatively, the labelling module 10b undergoes failure, whereas the labelling module 10a is operating normally.
In use, the aforesaid control unit therefore detects the non-nominal operating condition for the labelling module 10a.
According to the invention, when this non-nominal operating condition is detected, during the labelling process, by the control unit, the latter is configured to:

stop the labelling module 10a;
increase the speed, in particular the speed of rotation about the axis Y, of the feeding roll 15 of the labelling module 10b;
increase the speed, in particular the speed of rotation about the axis X, of the drum 14 of the labelling module 10b; and to
increase the speed of rotation of the plates 16 about axes thereof and, therefore, of the articles 3.

In particular, in the above non-nominal operating condition, the control unit is also configured to control the labelling module 10b so that it will label both the second articles 3 (as per nominal procedure) and the first articles 3.
In other words, according to the method set forth above, it is possible to prevent stoppage of the machine 1 and therefore continue the labelling process, directing the entire production workload onto the labelling module 10b that is functioning nominally.
In the meantime, once the failed labelling module 10a has been stopped and isolated, it is preferably possible to restore its operating conditions.
In the case in which the labelling module 10b alone is not designed for handling the entire rate of articles 3 required by the machine 1 (i.e. the number of articles 3 to be labelled per unit time), for example because its structural and functional specifications do not so allow, the control unit is further configured to control a reduction in speed of the carousel 6, in particular a reduction in the speed of rotation about the axis Z of the carousel 6.
In this way, a smaller number of articles 3 to be labelled will reach the application station A of the labelling module 10b, which will manage to handle the new rate (reduced with respect to the nominal rate) of the machine 1.
Conveniently, in the case in which the aforesaid non-nominal operating condition is detected for the labelling module 10a, the control unit is moreover configured to control:

an increase in the speed of the blade 12 of the labelling module 10b; and/or
an increase in the speed of the gluing roll 13 of the labelling module 10b.

In use, during advancement of the articles 3 along the path P, it is known to position (i.e., rotate) the articles 3 by the respective plates 16 in a pre-set nominal position in which they must be located at the corresponding application station A for receiving the corresponding label 2 in a nominal way.
This is particularly important in the case of articles 3 having a non-cylindrical shape, for example a prismatic shape with a substantially square base, or else with a square base with rounded corners, in so far as the pre-set point of start of application of the label 2 on the outer lateral surface of said articles 3 must be respected with precision, in order to apply the label 2 in a nominal way.
For this purpose, during the labelling process, the control unit is configured to control:

the positioning the first articles 3 in a first nominal position at the application station A of the labelling module 10a; and
the positioning the second articles 3 in a second nominal position at the application station A of the labelling module 10b.

In the case in which the non-nominal operating condition referred to above is detected for the labelling module 10a, in addition to execution of the steps described above, the control unit is further configured to position the first articles 3 in the second nominal position at the application station A of the labelling module 10b.
In this way, also the first articles 3 will be positioned in a nominal manner for being labelled by the labelling module 10b.
Once proper operation of the failed labelling module 10a has been restored, it is expedient for the latter to be automatically "re-integrated" in the production process, and consequently the speed of all the components mentioned above will again be regulated to the nominal operating conditions.
With reference to Figure 3, indicated as a whole by 1' is a labelling machine obtained according to an alternative embodiment of the present invention.
Since the machine 1' is structurally and functionally similar to the machine 1, only the substantial differences between the two machines will be described in the following, using, wherever possible, the same references.
In particular, the machine 1' differs from the machine 1 in that it comprises at least two labelling modules 10' (just one of which is illustrated in Figure 3) configured to apply, onto the articles 3, labels 2 of the type commonly known as "cold-glue labels".
More in particular, each labelling module 10' comprises:

a transfer device, in particular a known hook drum 17, configured to receive a respective succession of labels 2 at a corresponding receiving station R and to feed them to the carousel 6 at a corresponding application station A so as to apply them to the respective articles 3; and
a feeding device 18 configured to supply the aforesaid succession of labels 2 to the respective hook drum 17.

In detail, each feeding device 18 comprises:

a carousel 19, rotatably mounted on the corresponding labelling module 10', arranged peripherally with respect to the corresponding drum 17 and configured to feed a plurality of spindles 20 along a circular path, adapted to receive and hold, in manner known per se and not described in detail, a respective sequence of pre-cut labels 2; and
a distributor 21 configured to selectively supply the pre-cut labels 2 to the respective spindles 20.

In greater detail, each labelling module 10' further comprises a gluing device, for example a gluing roll 13' arranged peripherally with respect to the corresponding carousel 19 and configured to sequentially spread with glue the labels 2 carried by the respective spindles 20.
In use, the labels 2 are supplied to the carousel 19 and held by the corresponding spindles 20; simultaneously, the gluing roll 13 spreads, at least in part, the labels 2 with glue; then, the drum 17 picks up sequentially the labels 2 and transfers them, in a per se known manner and not described in detail, to the articles 3, carried in rotation by the plates 16, as described above for the machine 1.
Therefore, according to this embodiment, in the case where a non-nominal operating condition is detected for one of the labelling modules 10', the control unit is configured to:

stop the labelling module 10' for which the non-nominal operating condition has been detected; and
increase the rate of distribution of the labels 2 of the distributor 21 and the speed of the carousel 19, of the gluing roll 13, and of the drum 17 of the labelling module 10' that is functioning in the nominal way.

Preferably, in the case where the labelling module 10' that is functioning is not designed for handling the entire rate of articles 3 required by the machine 1' (i.e., the number of articles 3 to be labelled per unit time), the control unit is also configured to control a decreasing of the speed of the carousel 6.
With reference to Figure 4, a labelling machine obtained according to a third embodiment of the present invention is indicated as a whole by 1".
Since the machine 1'' is structurally and functionally similar to the machine 1 and the machine 1', only the substantial differences between these will be described in what follows, using the same references wherever possible.
In particular, the machine 1'' differs from the machine 1 and from the machine 1' in that it labels first articles 3a having a format different from second articles 3b.
In detail, the machine 1'' comprises an input device 22 that includes:

an input conveyor 23 configured to convey first articles 3a towards the star wheel 7;
an input conveyor 24 configured to convey second articles 3b towards the star wheel 7; and
a sorting device 25 configured to supply the first articles 3a and the second articles 3b to the carousel 6, in particular to the star wheel 7, in an alternating manner, as illustrated in Figure 4.

Preferably, the sorting device 25 comprises at least a wormscrew member, operating according to a modality known and not described in detail.
As specified above for the machine 1 or the machine 1', the labelling module 10a is configured to apply labels 2 onto the first articles 3a, whereas the labelling module 10b is configured to apply labels 2 onto the second articles 3b.
According to the invention, in the case in which the aforesaid non-nominal operating condition is detected for the labelling module 10a, the control unit is further configured to control the sorting device 25 so that it will cut off, i.e., prevent, supply of the first articles 3a to the carousel 6.
Alternatively, in the case in which the two successions of labels 2 comprise a first succession of labels 2 that are configured to be applied onto the first articles 3a and a second succession of labels 2 that are configured to be applied onto the second articles 3b and that have a format different from that of the labels 2 of the first succession, the entire production load is directed to the labelling module 10b that is functioning in a nominal way.
In practice, in the latter case, the control unit is configured to discard, at output from the carousel 6, the first articles 3a onto which the labelling module 10b has applied labels 2 of the second succession of labels 2.
In this way, the labelling process can proceed without any stoppage.
From an examination of the characteristics of the labelling machine 1, 1', 1'' made according to the present invention and of the method for applying labels 2 onto the articles 3 implemented by said machine 1, 1', 1'', the advantages that they afford are evident.
In particular, thanks to the aforesaid configuration of the machine 1, 1', 1" and of the method for applying labels 2 it is possible to prevent frequent stoppages of the machine 1, 1', 1'' in the case in which the control unit detects a non-nominal operating condition, i.e., a failure, in at least one of the labelling modules 10a, 10b, 10' .
In this way, the labelling process proves more efficient, faster, and more linear.
It is clear that modifications and variations may be made to the machine 1, 1', 1'' and to the method described and illustrated herein, without thereby departing from the scope defined by the appended claims.
In particular, the labelling machine 1, 1', 1'' could comprise more than two labelling modules 10a, 10b, 10', and the control unit could detect the aforesaid non-nominal operating condition in two or more of them.
Furthermore, it is clear that also the machine 1' is able to operate with first articles 3a and second articles 3b having a format different from the first articles 3a.

Claims

A method for applying labels (2) onto articles (3; 3a, 3b) adapted to contain a pourable product; said method comprising the steps of:
i) advancing a plurality of said articles (3; 3a, 3b) along a feed path (P) by means of a conveyor device (6);

ii) rotating said articles (3; 3a, 3b) about respective axes thereof during at least part of the step of advancing;

iii) feeding at least two successions of labels (2) to said conveyor device (6) by means of at least two labelling modules (10a, 10b; 10'), respectively;

iv) conveying said two successions of labels (2) from respective receiving stations (R) towards respective application stations (A), at which said labels (2) are applied onto respective articles (3; 3a, 3b) by means of respective transfer devices (14; 17), each of which is carried by a relative labelling module (10a, 10b; 10');

v) feeding said successions of labels (2) to the relative transfer devices (14; 17) at the respective receiving stations (R) by means of respective feeding devices (15; 18), each of which is carried by a corresponding labelling module (10a, 10b; 10'); and

vi) detecting a non-nominal operating condition in one (10a; 10') of said labelling modules (10a, 10b; 10');
wherein, in the case in which, during said step vi) of detecting, said non-nominal operating condition is detected in said one (10a; 10') of said labelling modules (10a, 10b; 10'), said method further comprises the steps of:
vii) stopping said one (10a; 10') of said labelling modules (10a, 10b; 10') for which said non-nominal operating condition is detected;

viii) increasing the speed of the feeding device (15; 18) of the other one (10b; 10') of said labelling modules (10a, 10b; 10');

ix) increasing the speed of the transfer device (14; 17) of said other one (10b; 10') of said labelling modules (10a, 10b; 10'); and

x) increasing the speed of rotation about, about the axes thereof, of said articles (3; 3a, 3b) conveyed by said conveyor device (6).
The method according to claim 1, further comprising the steps of:
xi) sequentially spreading said labels (2) with glue b means of respective gluing devices (13), each of which is carried by a relative labelling module (10a, 10b; 10'); and

xii) in the case in which, during said step vi) of detecting, said non-nominal operating condition is detected in said one (10a; 10') of said labelling modules (10a, 10b; 10'), increasing the speed of the gluing device (13) of said other one (10b; 10') of said labelling modules (10a, 10b; 10').
The method according to any one of the preceding claims, further comprising the steps of:
xiii) advancing first articles (3; 3a) and second articles (3; 3b) in an alternating manner along said feed path (P);

xiv) labelling said first articles (3; 3a) by means of said one (10a; 10') of said labelling modules (10a, 10b; 10');

xv) labelling said second articles (3; 3b) by means of said other one (10b; 10') of said labelling modules (10a, 10b; 10'); and

xvi) in the case in which, during said step vi) of detecting, said non-nominal operating condition is detected in said one (10a; 10') of said labelling modules (10a, 10b; 10'), issuing a command to said other one (10b; 10') of said labelling modules (10a, 10b; 10') for labelling said first articles (3; 3a) and said second articles (3; 3b).
The method according to claim 3, wherein said step xiii) of advancing comprises the steps of:
xvii) positioning said first articles (3; 3a) in a first nominal position at the application station (A) of said one (10a; 10') of said labelling modules (10a, 10b; 10');

xviii) positioning said second articles (3; 3b) in a second nominal position at the application station (A) of said other one (10b; 10') of said labelling modules (10a, 10b; 10'); and

xix) in the case in which, during said step vi) of detecting, said non-nominal operating condition is detected in said one (10a; 10') of said labelling modules (10a, 10b; 10'), positioning said first articles (3; 3a) in said second nominal position at the application station (A) of said other one (10b; 10') of said labelling modules (10a, 10b; 10').
The method according to claim 3, wherein said first articles (3a) have a format different from the format of said second articles (3b); the method further comprising the steps of:
xx) supplying said first articles (3a) and said second articles (3b) to said conveyor device (6) in an alternating manner by means of a sorting device (25); and

xxi) in the case in which, during said step vi) of detecting, said non-nominal operating condition is detected in said one (10a; 10') of said labelling modules (10a, 10b; 10'), issuing a command to said sorting device (25) for cutting off supply of said first articles (3a) to said conveyor device (6).
The method according to claim 3, wherein said first articles (3a) have a format different from the format of said second articles (3b) and wherein said two successions of labels (2) comprise a first succession of labels (2) configured to be applied onto said first articles (3a) by said one (10a; 10') of said labelling modules (10a, 10b; 10') and a second succession of labels (2) configured to be applied onto said second articles (3b) by said other one (10b; 10') of said labelling modules (10a, 10b; 10') and having a format different from that of the first succession; the method further comprising the step of:
xxii) in the case in which, during said step vi) of detecting, said non-nominal operating condition is detected in said one (10a; 10') of said labelling modules (10a, 10b; 10'), discard said first articles (3a) onto which said other one (10b; 10') of said labelling modules (10a, 10b; 10') has applied labels (2) of said second succession.
The method according to any one of the preceding claims, further comprising the step of:
xxiii) reducing the speed of said conveyor device (6).
The method according to any one of the preceding claims, wherein said two successions of labels (2) are obtained from respective webs (4) of labelling material; the method further comprising the steps of:
xxiv) sequentially separating said labels (2) from the respective webs (4) of labelling material using respective separation devices (12), each of which is carried by a corresponding labelling module (10a, 10b); and

xxv) in the case in which, during said step vi) of detecting, said non-nominal operating condition is detected in said one (10a) of said labelling modules (10a, 10b), increasing the speed of the separation device (12) of said other one (10b) of said labelling modules (10a, 10b).