WO2024252256A1

WO2024252256A1 - Method and unit for inspection of multi-segment rod-shaped articles

Info

Publication number: WO2024252256A1
Application number: PCT/IB2024/055401
Authority: WO
Inventors: Maria Eleonora CESARINI; Claudio Foghetti
Original assignee: GD SpA
Current assignee: GD SpA
Priority date: 2023-06-06
Filing date: 2024-06-03
Publication date: 2024-12-12
Anticipated expiration: 2025-12-06
Also published as: IT202300011412A1

Abstract

Described is a unit (1 ) for inspecting multisegment, rod-shaped articles (100), in particular defining or intended to define smoking articles, in particular intended to form smoking articles suitable for generating aerosols by heating. The unit (1 ) comprises at least one emitting device (3), configured for emitting a light beam (F) in the direction of an end surface (100a, 100b) of at least one article (100), and at least one detecting device (4), configured for capturing the light diffused by the end surface (100a, 100b) and produced by the light beam (F) and for generating a signal identifying the intensity of the light captured. The unit (100) also comprises a control unit (5), connected or connectable to the detecting device (4) and configured to receive the identification signal and to process the identification signal in such a way as to obtain information relating to the orientation of each article (100).

Description

METHOD AND UNIT FOR INSPECTION OF MULTI-SEGMENT ROD-SHAPED ARTICLES

Technical field

5 This invention relates to the tobacco industry and relates to a unit and a method for inspecting rod-shaped articles, in particular defining, or designed to define, smoking articles. More specifically, the rod-shaped articles are intended to form tobacco products suitable for generating aerosols by heating. 0

Background art

In the reference sector of this invention, the transfer is known of a plurality or mass of articles along a processing path or transfer by indirect guide, that is to say, by a lower guide (conveyor belt, lower wall of a tray, flexible 5 or movable wall for filling a hopper, or others) supporting the articles, wherein the articles interact with each other by contact friction and force of gravity. In this situation, the articles not directly supported by the guide are susceptible to uncontrolled alteration of their orientation with the consequent risk of rotating one or more articles about a direction which is 0 inclined relative to its axis.

On the other hand, in the reference sector of this invention the need is also known of packaging the articles in a packet in such a way that all the articles have a same orientation. 5 Aim of the invention

The aim of the invention is therefore to identify the orientation adopted by each article of a group or of a mass of articles, so as to identify whether the article is oriented in the correct direction or in the opposite direction. In effect, during the movement of a mass of articles or during a step of filling 0 volumes such as hoppers or trays, one or more articles may be positioned according to an overturned orientation, thus being unsuitable for the subsequent packaging.

Typically, the traditional smoking articles have different ends, having physical and visual properties which can be easily identified and, in the case of an overturned article, it can be easily identified with a simple optical inspection by means of capturing images.

However, articles of a recent type can be made with a filter segment at a first end and a closing segment, or “plug”, at the other end, between which further segments are interposed, for example tubular segments, a segment for generating aerosols, and so on. These articles are, for example, suitable for generating aerosols by heating, more specifically by heating by induction using a device in which the article is partly inserted.

Disadvantageously, these articles have the ends visually identical to each other, for example white. That is because the materials the filters and the closing segments are made of are visually similar. These materials are, for example, selected from the group comprising acetate, monoacetate or crimped paper.

For this reason, the filter segment and the closing segment, although having different axial lengths and being made of different materials, have the same appearance.

For this reason, it is difficult to identify the end surfaces defined by the filter segment by using a simple image captured by a video camera, since a distinction is in fact complex, if not unlikely, between the end defined by the filter segment and the defined end of the closing segment on the basis of aesthetic parameters such as, for example, colour, tone or surface effect.

An inspection performed using common image capturing techniques, for example using common cameras, would therefore be fruitless on account of the same appearance of the filter and closing segments.

However, it is known practice to perform this identification using a directional dependence, along the axis of extension of the article, of an absorption of a light beam. A solution of this type is described in patent application WO2021/165303.

In particular, this prior art application provides an emitting device, configured for emitting a light beam, in the direction of a side surface of at least one article, and a detecting device, configured to capture the light emitted at an end surface of the irradiated article (and generated by the light beam itself).

Due to the different axial lengths of the closing segment and the filter segment, the absorption of the light beam along the article (that is, from the side infeed surface to the end outfeed surface) is different depending on the length of the end segment and, therefore, the orientation of the article. In effect, this determines a different intensity of light released at different end surfaces of the same article, which can be adjusted and identified by means of a video camera.

However, this embodiment is affected by the drawback of not guaranteeing a sufficient precision in the identification of an orientation of rod-shaped articles, in particular in the case of articles positioned on several rows.

In particular, the Applicant has found that the inspection of articles positioned along rows superposed in accordance with the solution indicated above may be affected by errors since they would irradiate, using the light beam emitted by the emitting device, only the side surfaces of articles of a row facing the emitting device, causing an attenuation in the irradiating of innermost rows. This reduces the effectiveness of detection on more internal rows of articles. Obviously, the duplication of the device also on the other side could ideally partly overcome this shortcoming, but this would lead to a more complex and costly structure, which is in any case inadequate in the case of further inner rows of articles which would in any case be subject to the attenuation problem.

The inspection of traditional cigarettes is also known by optical control, performing a three-dimensional measurement of a profile of the end surfaces of the article.

A solution of this kind is described in patent document EP2677273.

In particular, the prior art teaches placing at least one optical sensor configured to irradiate an end surface of a cigarette, for example transported by mass flow or by a suitable drum, and performing a three- dimensional measurement of the irradiated end surface.

Using the optical sensors it is also possible to generate a two-dimensional image of the head surface to obtain qualitative information of an aesthetic nature such as, for example, any cavities due to escape of tobacco.

The Applicant has found that this solution is fruitless if applied for inspecting a group of articles after packaging in order to check a correct orientation of the articles.

A three-dimensional measurement is, in fact, aimed at detecting, and if necessary rejecting, products having aesthetic defects, such as, for example, recesses, protuberances, discoloration, marks and others, whilst in the case according to the invention the filter segment and the closing segment have the same aesthetic appearance and a surface appearance free of defects. For this reason, the solution proposed by patent document EP2677273 does not have any prospect of utility for the purpose of interest.

The aim of the invention is therefore to provide a unit and a method for inspecting multisegment articles which is able to guarantee an effective procedure for identifying the orientation of an article.

A further aim of the invention is to provide a unit and a method for inspecting multisegment articles which is able to achieve a high level of reliability, significantly limiting detection errors, in particular with reference to applications which involve inspecting articles positioned along superposed rows.

Lastly, the aim of the invention is to provide a unit and a method for inspecting multisegment articles which is able to simplify the structure necessary for the detection. The Applicant has found that by using an incident light beam striking an end surface of the article, thanks to the different degree of diffusion of the materials (different to each other) with which the closing segment and the filter segment are made, it is possible to detect in a precise and reliable manner information relative to the orientation of each article of a plurality of articles, for example positioned along rows of articles having respective axes parallel to each other. The arrangement on several rows is irrelevant on the intensity of lighting, since each row of articles in any case exposes the top surface of all the articles.

The technical purpose indicated and the aims specified are therefore achieved by a unit for inspecting multisegment articles and by a method for inspecting multisegment articles comprising the technical features described, respectively, in claims 1 and 7, and/or in one or more of the claims dependent thereon.

Brief description of the drawings

This invention is described below with reference to the accompanying drawings, which illustrate a non-limiting embodiment and in which:

- Figure 1 is a cross-section of an embodiment of a rod-shaped smoking article which can be inspected using the inspection unit and/or by applying the method according to this invention;

- Figure 2 is a schematic perspective view of a unit for inspecting multisegment articles, for example articles of Figure 1 , used for performing the method according to this invention;

- Figure 3 is a schematic and front view of the unit of Figure 2;

- Figure 4 shows a two-dimensional image generated by the unit of Figures 2 and 3 and/or by applying the method according to the invention.

Detailed description of preferred embodiments of the invention

In the accompanying drawings, the numeral “100” denotes in its entirety a multisegment article in the shape of a rod, and the numeral “1 ” denotes in its entirety a unit for inspecting articles 100 (shown schematically and only partly in the accompanying drawings) in accordance with the invention.

The term “multisegment, rod-shaped article” means a rod-shaped article divided into several segments and defining, or intended to define, a smoking article, in particular intended to form a smoking article suitable for generating aerosols by heating, preferably by heating generated externally by electromagnetic induction or by conduction.

The article 100, as shown in Figure 1 , extends along a respective axis of extension “X” between end surfaces 100a and 100b opposite to each other and comprises a side surface 100c extending between the end surfaces 100a and 100b.

The article 100 is divided at least into a filter segment 101 , a closing segment 102 and, interposed between the filter segment 101 and the closing segment 102, further segments designed for the formation and treatment of the aerosol. These further segments may preferably comprise a segment 103 of material suitable for generating aerosols by heating, and at least one tubular segment 104. For this reason, the filter segment 101 , the closing segment 102, the segment 103 and the tubular segment 104 are positioned in succession along the axis of extension “X”.

More in detail, the filter segment 101 and the closing segment 102 are intended to define, respectively, a first end surface 100a of the article 100 and a second end surface 100b of the article 100.

The segment 103 is located in a position adjacent to the closing segment 102, whilst the at least one tubular segment 104 is interposed between the segment 103 and the filter segment 101 .

The segment 103 may contain a generic material suitable for releasing an aerosol when heated, for example strips of tobacco or containing a tobacco aroma, or a sheet collecting tobacco or containing a tobacco aroma.

The at least one tubular segment 104 may act as a spacer element between the filter segment 101 and the segment 103 e/or as a cooling element, suitable for defining a decrease in temperature in the aerosol generated by suction of a user and by heating the segment 103.

Alternatively, the tubular segment 104 is a spacer and is followed by a cooling segment with a non-tubular structure.

According to the embodiment illustrated in Figure 1 , the tubular segment 104 is divided into a pair of pieces 104a, 104b, suitable to perform, respectively, the function of spacer element and the function of cooling element.

The filter segment 101 and the closing segment 102 of a same article 100 are made of materials different to each other, in particular selected from acetate, mono-acetate and crimped paper.

For example, in an article 100 the filter segment 101 and the closing segment 102 can be made, respectively, of acetate and crimped paper, as well as, respectively, of mono-acetate and acetate.

Even though they are made of different materials, the filter segment 101 and the closing segment 102 have the same appearance, in particular the same colour, same tone and same surface structure. In particular, they have a continuous end surface, preferably smooth, for example white in colour. For this reason, an immediate visual distinction cannot be made between the filter segment 101 and the closing segment 102, that is to say, between the first end surface 100a and the second end surface 100b, on the basis of aesthetic parameters.

As will be described in more detail below, the invention comprises positioning a plurality of articles 100 in a configuration mutually side by side with the respective axes of extension “X” parallel to each other, preferably with a predetermined number and distribution and suitable for defining the contents of a standard packet to be made or, alternatively, in a mass flow configuration (moving on a belt, lowering into a hopper) or, alternatively, in mass stored in trays or containers.

Subsequently, one of the end surfaces 100a, 100b of at least one article 100 is irradiated and, using the different optical degree of diffusion of the surfaces due to the different production materials, information is obtained regarding the orientation of the irradiated article 100.

The term “optical degree of diffusion” means the capacity of a material to diffuse a light beam, which strikes it, in a diffused beam according to a corresponding output angle.

The term “orientation” means the spatial arrangement of the article 100 along its axis. In particular, the article has two possible orientations, turned upside down relative to each other.

The procedures and means used for inspecting the articles 100 according to this invention are illustrated in detail below.

Preferably, the unit 1 is positioned along a advancement direction of the articles 100 and is stationary. Alternatively, the articles may be at least temporarily stationary and the unit 1 is moved. Alternatively, both the articles and the unit 1 are moved.

Preferably, the articles 100 are subject to indirect guide, where the indirect guide may be provided at the unit 1 or upstream of it. If the unit 1 is located in a remote position downstream of the indirect guide, there would be no drawback since the event which generates an erroneous orientation of one or more articles only generates an incorrect arrangement of the article, which remains unchanged up to the unit 1 .

The term “indirect guide” means a flow of articles 100 wherein only a small part of them is directly in contact with a guide unit, for example a conveyor belt or a movable wall.

For example, an indirect guide may be generated by falling into a hopper or by constrained guide of a main layer (lower) of articles 100 for generating, by a movement of the main layer, a movement of peripheral layers (upper) of articles 100 superposed on the main layer. This occurs, for example, in a mass-stream or when articles are transported in a container or tray.

For this reason, the indirect guide is indicated as an operating condition such as to cause, potentially, a misalignment of one or more articles such as to cause an overturning.

The unit 1 comprises at least one supporting element 2 (illustrated schematically in Figure 4) suitable for supporting a plurality of articles 100. The supporting element 2 is configured for supporting a plurality of articles 100 positioned with the respective axes of extension “X” parallel to each other. In other words, the supporting element 2 is configured for supporting a plurality of articles 100 positioned along at least one row, along which the articles 100 have axes of extension “X” parallel to each other.

Preferably, the supporting element 2 is configured for supporting a plurality of articles 100 positioned along a plurality of rows superposed on each other, in such a way that the articles 100 of different rows have respective axes of extension "X" parallel to each other.

According to the embodiment illustrated, the supporting element 2 is configured for supporting a plurality of articles 100, defined by a group of articles 100 with a predetermined number and distribution and suitable for defining the contents of a standard packet to be made and the unit 1 is preferably positioned upstream of a packaging station. The support 2 may therefore be a drawer of a drawer conveyor which feeds the articles from a hopper to a packaging machine.

More in detail, the supporting element 2 is suitable for supporting the articles 100 in such a way as to expose one of the end surfaces 100a or 100b of each article 100, or both.

In order to obtain information relative to an orientation of the articles 100, the invention comprises firstly irradiating at least one article 100 using at least one light beam “F”, as shown in Figures 2 and 3.

The light beam “F” is preferably a laser beam, more preferably a laser blade, suitable for irradiating at least one article 100 along a linear profile. Preferably, the laser blade is configured and/or oriented in such a way as to be transversal, preferably perpendicular, to the relative movement between articles 100 and unit 1 . According to an advantageous aspect of the invention, the light beam “F” is incident on one of the end surfaces 100a, 100b of the article 100, as shown in Figures 2 and 3.

Advantageously, as will become clearer as this description continues, by irradiating one of the end surfaces 100a, 100b it is possible to detect a diffused light intensity using a suitable device, and use this intensity to detect information relating to an orientation of the article 100. In effect, the filter segment 101 , defining the first end 100a, and the closing segment 102, defining the second end 100b, are made of respective materials different to each other, which correspond to different optical levels of diffusion and therefore different intensity of light diffused by them when irradiated by the light beam “F”.

Advantageously, moreover, by irradiating one of the end surfaces 100a, 100b of at least one article 100, it is possible to irradiate in a direct manner each article 100 of the plurality of articles 100, even in the case of articles 100 positioned along superposed rows.

The term “direct manner” means irradiating each article 100 in the absence of obstacles, different from the article 100 to be irradiated, interposed between the article 100 to be irradiated and a source of the light beam “F”.

More in detail, the light beam “F” is emitted along a direction or emission plane “E” (schematically illustrated in Figure 3) incident on one of the end surfaces 100a, 100b of at least one article 100 and having a predetermined angle, defined by a respective emission angle “OE”, relative to a plane in which the irradiated end surface 100a, 100b lies.

Preferably, the angle of emission “OE” is between 10° and 80°, and more preferably between 30° and 60°.

In order to irradiate at least one article 100, the unit 1 comprises at least one emitting device 3, configured for emitting the light beam “F” along the direction of emission “E”. The light beam may be such as to strike a single row of articles or such as to simultaneously strike two or more side by side rows of articles.

According to an embodiment of the unit 1 , the emitting device 3 comprises a laser emitting device, configured for emitting a laser light and more preferably configured for emitting a laser blade.

The emitting device 3 is positioned facing the supporting element 2 in such a way as to emit the light beam “F” in the direction of one of the end surfaces 100a, 100b of at least one article 100. In other words, the emitting device 3 has a portion suitable for emitting the light beam “F” facing the supporting element 2 and, in particular, at one of the end surfaces 100a, 100b of at least one article 100 supported by the supporting element 2.

A similar emitting device 3 may be positioned on the opposite side, configured for emitting the light beam “F” in the direction of the other opposite end surface 100a, 100b of at least one article 100.

According to an advantageous aspect of this invention, once the article 100 has been irradiated by the light beam “F”, at least one signal is generated identifying the light intensity of the light diffused by the end surface 100a, 100b irradiated by the light beam “F”, and the signal generated is processed to obtain information relating to the orientation of each article 100 of the plurality of articles 100.

Advantageously, the different optical degree of diffusion of the materials with which the end surfaces 100a, 100b are made allows an identification signal associated with the first end surface 100a to be obtained which is different from the identification signal associated with the second end surface 100b.

By processing the identification signal it is possible to distinguish the end surfaces 100a, 100b and thus obtain reliable information relative to an orientation of the article 100.

In other words, different levels of diffusion induce different amplitudes of emission of the light diffused by the surfaces, and this translates into a different detected intensity. The Applicant has also found that, by means of an action for adjusting the wavelength of the light beam, it is possible to obtain a greater differentiation between the signals generated by the first and the second end surfaces 100a, 100b, thus obtaining an improved reliability of the detection.

Preferably, the step of generating the identification signal is carried out by optical inspection, carried out along a detection direction “R” incident on the end surface 100a, 100b to be detected and inclined by a detection angle “OR” relative to the plane in which the end surface 100a, 100b to be detected lies.

Preferably, as shown in Figure 3, the detection angle “O ” is different from the emission angle “OE”.

More preferably, the direction of detection “R” is perpendicular relative to the plane in which the irradiated end surface 100a, 100b lies.

In order to perform the capturing of the identification signal, the unit 1 comprises at least one detecting device 4, configured for capturing along the detection direction “R” the light diffused by the end surface 100a, 100b, irradiated using the light beam “F” emitted by the emitting device 3, and for generating a signal identifying the intensity of the light captured.

For this reason, the detecting device 4 is positioned facing the supporting element 2, and is alongside the emitting device 3. More in detail, the emitting device 3 and the detecting device 4 have respective emission directions “E” and detection directions “R” striking the same end surface 100a, 100b of the article 100 as shown in Figure 3 and preferably different to each other, in particular angled.

The unit 1 also comprises a control unit 5, configured to receive and process the signal generated by the detecting device 4.

In particular, the control unit 5 is connected or connectable to the detecting device 4, for example by suitable wiring, wireless connection or other types of connections.

Preferably, the method comprises irradiating both the end surfaces 100a, 100b of at least one, more preferably of each, article 100 for generating identification signals relating to each end surface 100a, 100b of the same article 100 and comparing them to each other.

Advantageously, in this way it is possible to obtain an improved reliability of the information regarding the orientation of each article 100, in particular relative to the reciprocal position between a first and a second end surface 100a, 100b of the article 100.

For this purpose, the unit 1 , according to a relative embodiment (not illustrated in the accompanying drawings), comprises a pair of emitting devices 3, each positioned facing the supporting element 2 and positioned and/or configured for irradiating respective end surfaces 100a, 100b opposite each other of at least one article 100, and a pair of detecting devices 4, each alongside the respective emitting device 3.

Preferably, the two detecting devices 4 are positioned in such a way that the respective directions of emission “E” and the directions of detection “R” are substantially identical in such a way as to act simultaneously on the two opposite end surfaces 100a, 100b of the same article 100.

Alternatively, the two detecting devices 4 are located at positions which do not correspond or are not aligned with each other and there is a correlation between the identification signals generated by the two detecting devices 4 in such a way that they are associated with the corresponding article 100.

In accordance with an aspect of the invention, the generation of the identification signal is performed by capturing at least one two-dimensional image 300 containing the detected end surface 100a, 100b, that is to say, irradiated by the light beam “F”. In other words, the step of generating the identification signal comprises a step of capturing at least one image 300 identifying the intensity of light diffused by the end surface 100a, 100b irradiated by the light beam “F”.

Preferably, the image 300, as shown in Figure 4, comprises a plurality of end surfaces 100a, 100b of a respective plurality of irradiated articles 100. More in detail, the first and second end surfaces 100a, 100b included in the image 300 have different aesthetic aspects, in particular they have different intensities to each other.

Advantageously, therefore, the image 300 allows the first end surface 100a to be distinguished in a precise and facilitated manner from the second end surface 100b.

The image 300 is acquired by capturing a single image capture for each article or, alternatively, combining with each other a plurality of images of the same articles at successive points in time, corresponding to different positions of the laser blade on the same article. This allows a greater detection effectiveness, since the effect of capturing the intensity is amplified by the plurality of scans performed and any presence of rows due to the blade structure of the illuminating beam is compensated.

Preferably, the invention comprises irradiating the article 100 using a laser light having a wavelength of between 390 nanometres and 415 nanometres and more preferably equal to 405 nanometres (blue colour).

Advantageously, this technical feature makes it possible to obtain an image 300 representing the first end surface 100a and the second end surface 100b with intensity which can be easily distinguished from each other, for example having respectively shades of grey and black or shades of black and white.

Preferably, the image 300 is captured by adjusting the exposure time taken to capture the image 300, preferably setting the exposure time to a value of between 5 microseconds and 30 microseconds, more preferably setting the exposure time to a value equal to 10 microseconds, 20 microseconds, or 25 microseconds.

In order to capture the image 300, the detecting device 4 of the unit 1 comprises a video camera, preferably CCD, configured to generate an image 300 containing the end surface 100a, 100b irradiated by the light beam “F”.

The image 300 captured is then transmitted to the control unit, which is programmed to process the image 300.

The processing of the signal comprises processing the image 300 captured in such a way as to distinguish the first end surface 100a from the second end surface 100b of the article 100, in order to derive information relative to an orientation of the article 100, that is to say, to a mutual positioning between the first and the second end surface 100a, 100b.

In accordance with an aspect of this invention, the processing of the image 300 is carried out by means of an algorithm for analysing digital images.

More in detail, the processing of the image 300 is performed by identifying at least a region of the image 300 corresponding to the irradiated end surface 100a, 100b and considering the filling intensity of the region identified.

This processing may be performed by comparing the intensity of filling of each region with a reference intensity.

If the intensity of the region does not correspond to the reference intensity, it is possible to obtain information relating to the orientation of the corresponding article, including non-conformity information of the orientation of the article.

The processing may, alternatively, be performed by comparing the filling intensity of each region with the filling intensity of an adjacent region and/or with the filling intensity of the other regions present in the image 300, in such a way as to identify a value of normal intensity, that is to say, recurring between the regions. Consequently, regions (non-conforming) having an intensity value different from the normal intensity value detected (conforming regions) can be detected.

For this reason, in the latter case, the processing is performed by identifying a recurrence of the filling intensity of the regions contained in the image 300 to check for the presence, in the image 300, of regions excluded from this recurrence.

In the event of the presence of regions excluded from the above- mentioned recurrence, it is possible to obtain information regarding the orientation of the corresponding articles 100 including non-compliance information in the orientation of one or more articles 100.

The processing may also be performed by comparing the image 300, containing a plurality of articles 100, with a reference image.

If the image 300 deviates excessively from the reference image, that is to say, does not correspond to the reference image, it is possible to obtain information relating to an orientation of the articles 100 including information of a non-conformity in the orientation of one or more articles 100.

In order to perform the processing of the signal generated, the control unit 5 of the unit 1 may be configured to perform a comparison between the detected image 300 and a reference image.

The control unit 5 may also be configured for implementing an algorithm for analysing digital images.

According to an aspect of the invention, there is a step of rejecting the plurality of articles 100 inspected if the processing step highlights at least one article 100 oriented in a non-compliant manner.

The invention achieves the above-mentioned aims, eliminating the drawbacks highlighted in the prior art: in this regard, it should be noted that the method for inspecting articles 100, as well as the unit 1 , as claimed and/or described, are able to identify the orientation of individual articles 100 of a plurality of articles 100 in a compact manner and with improved reliability.

This result has been achieved by exploiting the different optical degree of diffusion of the different materials with which the end surfaces 100a, 100b of each article 100 are made.

In particular, this result is achieved by irradiating one of the end surfaces 100a, 100b of at least one article 100 using the light beam “F” and detecting an intensity of the light diffused by it in such a way as to obtain, based on this intensity, an orientation of the article 100.

Claims

1. A unit (1 ) for inspecting multisegment, rod-shaped articles (100), in particular defining or intended to define smoking articles, in particular intended to form smoking articles suitable for generating aerosols by heating, wherein each article (100) extends along a respective axis of extension (X) between opposite end surfaces (100a, 100b), made from respective different materials, and comprising a side surface (100c) extending between said end surfaces (100a, 100b), and wherein the unit (1 ) comprises:

- at least one supporting element (2) configured to support a plurality of articles positioned with their respective axes (X) parallel to each other;

- at least one emitting device (3), positioned to confront the supporting element (2) and configured to emit a light beam (F) in the direction of an end surface (100a, 100b) of at least one article (100) of the plurality of articles (100) in such a way that the light beam (F) is incident on one of the end surfaces (100a, 100b) of the article (100);

- at least one detecting device (4), positioned to confront the supporting element (2) and configured to capture the light diffused by the end surface (100a, 100b) and produced by the light beam (F) and to generate an identification signal identifying the intensity of the light captured;

- a control unit (5) connected or connectable to the detecting device (4) and configured to receive the identification signal and to process the identification signal to obtain an information item relating to the orientation of each article (100) of the plurality of articles (100), in particular relating to the relative position between a first and a second end surface (100a, 100b) of the article (100).

2. The unit (1 ) according to claim 1 , wherein the emitting device (3) is juxtaposed with the detecting device (4) and wherein the emitting device (3) and the detecting device (4) respectively have an emitting direction (E) and a detecting direction (R), different from each other and incident upon an end surface (100a, 100b) of at least one article (100) positioned on the supporting element (2), preferably the emitting direction (E) and the detecting direction (R) being inclined at different angles (OE, OR) to a positioning plane of the end surface (100a, 100b) of the article (100).

3. The unit (1 ) according to claim 1 or 2, wherein the emitting device (3) comprises a laser emitter, in particular a laser blade emitter, the emitting device (3) preferably emitting laser light with a wavelength of between 390 nanometres and 415 nanometres, more preferably equal to 405 nanometres.

4. The unit (100) according to any one of the preceding claims, wherein the detecting device (4) comprises a camera which faces the end surface (100a, 100b) to be inspected and which is configured to capture a two- dimensional image (300) containing the detected end surface (100a, 100b) of the article (100) and to transmit the image (300) to the control unit (5).

5. The unit (1 ) according to claim 4, wherein the control unit (5) is configured to compare the image (300) with a reference image and/or to run a digital image analysis algorithm, in particular identifying at least one region of the image (300) corresponding to the detected end surface (100a, 100b) of the at least one article (100) and considering the filling intensity of the at least one region.

6. The unit (1 ) according to any one of the preceding claims, wherein the supporting element (2) is defined by a cleat of a cleated conveyor, the cleat being configured to support a plurality of articles (100) arranged along at least one row comprising articles (100) having respective axes of extension (X) which are parallel to each other and preferably to support a plurality of articles (100) arranged along a plurality of superposed rows.

7. A method for inspecting multisegment, rod-shaped articles (100), in particular defining or intended to define smoking articles suitable for generating aerosols by heating, wherein each article (100) extends along a respective axis of extension (X) between opposite end surfaces (100a, 100b), made from respective different materials, wherein the method is preferably operable by an inspection unit (1 ) according to one or more of the preceding claims, the method comprising the following steps:

- providing a plurality of articles (100) arranged along at least one row and positioned in a mutually juxtaposed configuration with their respective axes of extension (X) parallel to each other;

- irradiating at least one article (100) of the row with at least one light beam (F) incident upon one of the end surfaces (100a, 100b) of the article (100);

- generating at least one identification signal identifying the intensity of the light diffused by the end surface (100a, 100b) and produced by the light beam (F);

- processing the signal to obtain an information item relating to the orientation of each article (100) of the plurality of articles (100), in particular relating to the relative position between the first and the second end (100a, 100b) of the article (100).

8. The method according to claim 7, wherein the step of generating the identification signal comprises a step of capturing a two-dimensional image (300) containing the detected end surface (100a, 100b) of the article (100) and a step of transmitting the image (300) to the control unit (5).

9. The method according to claim 7 or 8, wherein the step of generating a two-dimensional image (300) is carried out by a camera, preferably a CCD camera.

10. The method according to claim 8 or 9, wherein the step of processing the signal to obtain an information item relating to the orientation of each article (100) in the row is carried out by a digital image analysis algorithm, in particular identifying at least one region of the image (300) corresponding to the detected end surface (100a, 100b) of the at least one article (100) and considering the filling intensity of the at least one region.

11. The method according to claim 10, wherein the step of processing the signal is also accomplished by comparing the filling intensity with a reference intensity.

12. The method according to claim 10, wherein the step of processing the signal is also accomplished by comparing the filling intensity with the filling intensity corresponding to an adjacent article (100) or one belonging to the plurality of articles (100) in order to identify an intensity different from normal detected value.

13. The method according to claim 8 or 9, wherein the step of processing the signal to obtain an information item relating to the orientation of each article (100) in the row is carried out by comparing the image (300) with a reference image.

14. The method according to any one of claims 7 to 13, wherein the step of irradiating the articles (100) is carried out by directing the light beam (F) at a predetermined angle to a positioning plane of the end surface (100a, 100b) to be inspected, the predetermined angle being between 10° and 80, preferably between 30° and 60°.

15. The method according to any one of claims 7 to 14, wherein the light beam (F) is a laser beam, preferably a laser blade.

16. The method according to any one of claims 7 to 15, wherein the laser beam has a wavelength of between 390 nanometres and 415 nanometres, more preferably equal to 405 nanometres.

17. The method according to claim 14, wherein the step of generating at least one identification signal identifying the intensity of the light diffused by the end surface irradiated by the light beam (F) is accomplished by optical inspection along a detecting direction (R) different from the predetermined angle of the light beam (F) and/or along a direction perpendicular to the positioning plane of the end surface (100a, 100b) to be inspected.

18. The method according to any one of claims 7 to 17, wherein the multisegment article (100) comprises at least one filter segment (101 ), positioned at one end of the article, and a closing segment (102), positioned at the opposite end, the filter segment (101 ) and the closing segment (102) being made of different materials and having the same aesthetic aspect, in particular the same colour, the same hue and the same surface structure.

19. The method according to any one of claims 7 to 18, wherein the end surfaces (100a, 100b) of the article (100) are defined by respective segments (101 , 102) made of different materials, selected from the following: acetate, monoacetate or crimped paper.

20. The method according to any one of claims 7 to 19, wherein the plurality of articles (100) is defined by a group of articles (100) whose number is predetermined and which is suitable for defining the content, in terms of number and distribution, of a standard packet to be made.

21 . The method according to any one of claims 7 to 20, further comprising a step of discarding the plurality of articles (100) if the step of processing the identification signals relating to the articles (100) of the plurality of articles (100) shows that at least one article (100) is oriented in a nonconforming manner.