This application is a 371 of PCT/EP2019/077718, filing date Nov. 10,2019.

TECHNICAL FIELD

The present invention relates to a labelling machine for handling a web-like labelling material in an automated labelling process, in particular to a labelling machine configured for applying labels onto articles, such as bottles, containers, or the like.

The present invention also relates to a method for handling a web-like labelling material in an automated labelling process during which labels are applied onto articles, such as bottles, containers, or the like.

BACKGROUND ART

Labelling machines are known, which are commonly used to transport, prepare and apply labels onto articles, such as bottles, containers, or the like destined to be filled with a pourable product, in particular a pourable food product.

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 wound around one or more coils.

In detail, the web of labelling material is cut in labels of equal length, upon which glue is applied by gluing means (such as a gluing roller, spray and injector systems or the like) and which, finally, are conveyed and applied onto respective articles.

According to an alternative mode of carrying out the labelling process, sleeve labels, i.e. tubular-like labels, are obtained from a web of heat-shrinkable labelling material.

In particular, such sleeve labels are applied onto the respective articles with a certain backlash and then are heated up in an oven, so as to cause them to shrink and perfectly adhere onto the lateral surfaces of the same articles. This last configuration does not require the use of any glue or gluing means.

Regardless of the type of label, a known labelling machine 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 fed to the carousel;an output station, at which the labelled articles exit the carousel; anda labelling module, 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.

Generally, the labelling module comprises:one or more storage units, for example reels or coils around which the web of labelling material is wound;a plurality of unwinding rollers, which support, in use, the web progressively unwound from the reels and guide it, in use, along a feeding path;a cutting device, for example a knife, configured to cut a sequence of single labels having equal length from the web of labelling material; anda vacuum drum configured to receive, retain and advance each label previously cut by the cutting device and to feed each label to the carousel, at the application station.

Typically, the labelling module further comprises at least one transfer roller, configured to receive the web from the unwinding rollers and to transfer a plurality of labels obtained from such web to the vacuum drum. Generally, the cutting device is arranged peripherally to such transfer roller.

In case that the glue labels are used, the labelling module further comprises gluing means, usually a gluing roller arranged peripherally to the vacuum drum, in particular substantially tangent to the vacuum drum, and configured to apply glue at least onto the end portions (leading end portion and trailing end portion) of each label advanced by the same vacuum drum.

Normally, the vacuum drum has an approximately cylindrical or toroidal lobed configuration and is mounted, in a rotatable manner about its axis, on a stationary distributor member of the labelling module.

In detail, the vacuum drum is configured to receive and retain a succession of labels, previously cut by the cutting device at a receiving station and, after a rotation of a certain angle about its axis, to release the labels at the application station, so that such labels can be applied onto respective articles advanced by the carousel.

Accordingly, the carousel, the vacuum drum, the gluing roller and the transfer roller are conveniently phased and synchronized in order to correctly perform the whole labelling operation.

According to some configurations known in the art, the stationary distributor member has first air passages connected to a vacuum source; the vacuum drum is in turn provided with second air passages, which are configured to communicate with the first air passages at certain angular positions of the drum as it rotates about its axis, and end into a plurality of vacuum ports formed through an outer lateral surface of the drum for receiving the labels.

More precisely, the vacuum ports are formed in a plurality of damping pads (leading damping pads and trailing damping pads) and intermediate sections which, together, define the outer lateral surface of the vacuum drum.

In detail, the pads are organized in pairs, each pair including a leading pad, a trailing pad and an intermediate section between these latter.

In practice, when being retained by the vacuum drum, a label shall typically have the leading end held on one leading pad, the trailing end held on one trailing pad and the remaining (intermediate) part held on a section of the outer lateral surface comprised between the two mentioned pads (i.e., the corresponding intermediate section).

In light of the above, the distance between a leading pad and a trailing pad is substantially equal to the length of the strip of labelling material, i.e. the label, to be processed as measured along the circumference of the vacuum drum.

Furthermore, the height of the vacuum drum is approximately equal to the height of the label to be processed as measured parallel to the rotation axis of the vacuum drum. In practice, the height of the vacuum drum is slightly less than the height of the label to be processed, so that the upper and lower edges of the label overhang the vacuum drum by a few millimetres, which helps prevent glue from contaminating the vacuum drum surface.

It is known in the field of labelling machines the undesired eventuality in which a label is not applied onto the relative article and, therefore, remains stuck onto the vacuum drum despite having passed the application station (unapplied label). This condition can happen mainly for the following reasons:the article is not present on the carousel or it is not in the nominal position in which it should be in nominal operating conditions; orthe article is present on the carousel but the label is not applied thereon due to an excess of glue applied by the gluing roller; and/orthe article is present on the carousel but the label is not applied thereon because of a non-nominal positioning of the label onto the vacuum drum, for example because of a cutter-related fail or a vacuum-related fail.

Regardless of the reason, the unapplied labels can cause overlapping of other subsequent labels fed to the vacuum drum in the same positions between the pairs of pads retaining the unapplied labels.

This can lead to production jammings, waste of labelling material and, in the case of non-nominally positioned labels, glue spread onto the surface of the vacuum drum.

In order to avoid the aforementioned problems, according to a known solution labelling machines comprise detection means arranged peripherally to the vacuum drum in a position downstream of the application station and upstream of the receiving station and configured to detect the presence of labels onto the vacuum drum downstream of the application station and to generate a presence signal correlated with the presence of such labels downstream of the application station.

In detail, the detection means, usually consisting in one or more optical sensors, generate a presence signal when the presence of an unapplied label onto the vacuum drum downstream of the application station is detected. This presence signal is then sent to a control unit, which, on the basis of the presence signal received from the detecting means, commands the labelling machine to stop.

In this way, production jammings, waste of labelling material and unnecessary and unwanted glue waste and spreading are avoided.

Together with the control signal, the detection means generate an alarm signal, alerting the operator that a problem has occurred.

Although being functionally valid, the above-described solution leaves room to further improvement. In particular, a need is felt to perform an easy, cost-effective and time-effective troubleshooting of the causes due to which labels are not applied onto articles and are still retained onto the vacuum drum despite having passed the application station.

DISCLOSURE OF INVENTION

It is therefore an object of the present invention to provide a labelling machine, which is designed to meet the above-mentioned need in a straightforward and low-cost manner.

This object is achieved by a labelling machine as claimed in claim1.

It is another object of the present invention to provide a method of labelling, which is designed to meet the above-mentioned need in a straightforward and low-cost manner.

This object is achieved by a method of labelling as claimed in claim14.

