METHOD FOR MAKING ROD-SHAPED ARTICLES

Technical field

This invention relates to a method for making rod-shaped articles. More specifically, the term "rod-shaped articles" is used generally herein to denote products such as, for example, cigarettes, cigars, cigarillos, electronic cigarettes and like products but also semi-products of these products, such as filters and active portions for releasing a substance to be inhaled.

Background art

The term "cigarette" is used generally to denote any rod-shaped article comprising at least a filter, an active portion and a connecting strip for connecting the active portion and the filter to each other.

The cigarette may, for example, be a traditional cigarette which can be smoked by burning the end of the cigarette segment defining the active portion, or it may be an electronic cigarette which may be inhaled by heating but not burning the active portion.

In effect, the active portion may be a traditional cigarette segment comprising tobacco wrapped in paper or it may be an aerosol-generating element, that is, a heat-not-burn type tobacco containing product. In this case, the tobacco may be, for example, pre-treated, reconstituted, homogenized or cast-leaf tobacco.

Typically, rod-shaped articles of the type mentioned above comprise a wrapper - of paper, for example - in which they are wrapped.

The machines which make the rod-shaped articles, therefore, typically include rolls of wrapping material of various kinds which are unwound into continuous webs and then processed, if necessary, and used, for example, to make connecting strips for the cigarettes or coverings for the continuous rods of tobacco or filter material to make the filters or the active portions.

To meet the wide range of needs of manufacturers of rod-shaped articles and to cater for the different needs and tastes of consumers, the webs of paper are often further processed before being used to make the article. Processing the web may include applying a feature such as, for example, a decorative patch, a print or a flavouring.

In prior art machines, these features are normally applied at very high speeds: a very high level of precision is therefore required of the machine for application to be carried out correctly and to meet acceptability criteria. In many cases, the station where the features are applied are nevertheless subject to faults and malfunctioning which may lead to interruptions or irregularity which reflect negatively on the integrity and/or quality of the article.

Operating at high speeds, however, means that it would be impracticable to stop the machine to remove the defective parts of the web because it would involve lengthy, timewasting downtime; therefore, save in cases of unacceptable faults where shutting down the machine to eliminate the unusable stretches of web is absolutely necessary, production is normally allowed to continue, using even the defective parts of the web for the sake of continuity of production.

Once the articles have been made, the machine identifies those made with the defective stretches of the web and rejects them.

The Applicant has found that it is not always possible to detect the defects on the articles.

Indeed, if the feature is applied on the surface of the web which, when the article is finished, is on the inside of the article or if the feature is applied on the surface of the web which, when the article is finished, is on the outside of it but is not visible or is difficult to detect because, for example, it is hidden/surmounted by another element, the machine is unable to detect the defect caused by the incorrect application of the feature on the paper.

In this case, to be able to have a good level of certainty that only good articles are accepted, it is possible reject a number of articles in excess of the number of articles that certainly contain the defect.

In fact, using complex machine calculation and setting processes, it is possible to obtain a one-to-one match between the instant a defect is detected on the paper web and the instant an article containing the stretch of web affected by that defect moves past a selective rejection station, in order to reject the defective article.

Precisely identifying the article to be rejected is, however, very complicated and may be influenced by several factors which reduce reliability, including incorrect web tensioning and the fact that the web may be temporarily stored in a buffer.

Disclosure of the invention

In this context, the technical purpose which forms the basis of this invention is to propose a method for making rod-shaped smoking articles to overcome one or more of the above mentioned drawbacks of the prior art.

More specifically, this invention has for an aim to provide a method for making rod-shaped articles allowing defective articles to be identified and rejected, where the defects are not detectable or are difficult to see from the outside.

A further aim of this invention is to provide a method for making rod- shaped articles which allows improving the quality of the articles and the efficiency of the production process.

The technical purpose indicated and the aims specified are substantially achieved by a method for making rod-shaped articles, comprising the technical features described in one or more of the appended claims.

More specifically, this invention provides a method for making rod-shaped articles comprising the following steps:

- feeding a continuous web of wrapping material having a feature and/or an additional item applied to the web in an application zone of the web, - after the step of feeding, detecting the presence and/or at least one property of the feature and/or of the additional item in the application zone and determining whether the feature and/or the additional item in the application zone meets at least one criterion of acceptability,

- if the criterion of acceptability is not met, applying a marking on the web in the application zone or within a predetermined distance from the application zone,

- making a succession of rod-shaped articles using the web,

- identifying the articles with the markings on them and activating a procedure for rejecting the articles with the markings.

Advantageously, when a defect is detected, applying a marking on the defective part of the web before making the article allows subsequently detecting the defective articles easily and effectively and rejecting only those articles, thus avoiding needless waste and without interrupting production.

The dependent claims, which are incorporated herein by reference, correspond to different embodiments of the invention.

Brief description of the drawings

Further features and advantages of this invention are more apparent in the detailed description below, with reference to a preferred, but non-exclusive embodiment of a method for making rod-shaped articles, as illustrated in the accompanying drawings, in which:

- Figure 1 is a schematic view of an embodiment of a plant for making rod-shaped articles configured to implement the method according to this invention;

- Figure 2 is a schematic plan view of a stretch of web during a step of applying a feature and/or an additional item in an application zone of the web according to the method of this invention;

- Figure 3A is a schematic plan view of a stretch of web during a step of applying a marking on the web according to the method of this invention; - Figure 3B is a schematic plan view of a stretch of web during a step of applying a marking on the web, according to an alternative embodiment of the marking, in the method of this invention; and

- Figure 4 is a schematic perspective view of an article with a marking applied according to the method of this invention.

Detailed description of preferred embodiments of the invention

The method of this invention for making rod-shaped articles, hereinafter referred to simply as articles 1 , comprises an initial step of feeding a continuous web of wrapping material 2 (for example, paper), hereinafter referred to simply as web 2, having a feature 4a and/or an additional item 4b applied on the web 2 in an application zone 5 of the web 2, as illustrated in Figure 2.

Preferably, the step of feeding the web 2 is carried out by unwinding the web 2 from a roll 3.

Preferably, the step of feeding the web 2 comprises the sub-step of applying the feature 4a and/or additional item 4b in the application zone 5. More specifically, the inventive concept encompasses the presence of two more application zones intended to form part of the same finished article. Preferably, the feature 4a comprises at least one operation selected from among scoring, embossing, perforating, tearing, splicing of segments of web 2.

Preferably, the additional item 4b comprises a print, a label, an adhesive pattern, a tape, a flavouring material and/or an additive.

In the embodiment of the web 2 illustrated in Figure 2, for example, an additional item 4b is applied in the application zone 5.

After the step of feeding, the method comprises a step of detecting the presence and/or at least one property of the feature 4a and/or of the additional item 4b in the application zone 5 and determining whether the feature 4a and/or the additional item 4b in the application zone 5 meets at least one criterion of acceptability. In other terms, the method comprises detecting faults, defects or errors applying the feature 4a and/or the additional item 4b in the application zone 5 of the web 2.

Preferably, the step of detecting the presence and/or at least one property of the feature 4a and/or of the additional item 4b in the application zone 5 comprises the sub-steps of comparing the application zone 5 with an image or reference parameter and determining a deviation from that image or reference parameter.

In other terms, the method comprises detecting at least one physical/technical/chemical property of the feature 4a and/or of the additional item 4b applied in the application zone 5 and then checking/comparing what has been detected against at least one criterion of acceptability to determine whether the feature 4a and/or the additional item 4b has been made/applied correctly by checking whether the deviation, if any, falls within predetermined tolerances or specific settings. Preferably, the step of detecting the presence and/or at least one property of the feature 4a and/or of the additional item 4b is accomplished using one or more of the following: a video camera, a stills camera, a sensor, a photocell.

Preferably, the criterion of acceptability is based on a parameter selected from the following: shape, position, colour, size, physical condition, alignment, orientation, density, chemical composition.

If the at least one criterion of acceptability is not met, the method advantageously comprises a step of applying a marking 6 on the web 2 in the application zone 5 or within a predetermined distance from the application zone 5.

It should be noted that the expression "within a predetermined distance from the application zone 5" is used to mean not only that the marking 6 can be made on the same side of the web 2 as that where feature 4a and/or the additional item 4b is applied but also that it can be made on the opposite side of the web 2. That way, a defect detected can be associated with a marking for recognizing the defect so that the articles 1 affected by that defect can be selectively rejected, as will become clearer as this description continues. Preferably, the marking 6 made on the web 2 comprises at least one operation selected from scoring, printing, perforating, tearing, application of an additional element (for example a patch).

Preferably, also, the marking 6 is applied at a distance from the application zone 5 such as to be located on the same article 1 in which the feature 4a or additional item 4b does not meet the criterion of acceptability

That way, it is possible to trace the defective portions of web 2 and mark them so as to make them recognizable/detectable and identifiable, as will become clearer as this description continues.

The method then comprises the step of making a succession of articles 1 using the web 2, followed by a step of identifying the articles 1 with the marking 6 on them and activating a procedure for rejecting the articles 1 with the markings 6 on them.

That way, advantageously, only the articles 1 that are defective are rejected.

Preferably, the step of identifying the articles 1 with the marking 6 on them is accomplished using one or more of the following: a video camera, a stills camera, a sensor, a photocell.

Advantageously, thanks to this invention, it is therefore possible to identify the articles 1 that comprise defects or flaws and proceed to reject those and only those. That way, production may continue without interruption and rejection is limited to only those articles 1 which actually have the defects or flaws that do not meet predetermined criteria of acceptability. Preferably, furthermore, in a possible embodiment of the method, the feature 4a and/or the additional item 4b is applied on a first surface 2a of the web 2 and the marking 6 is applied on a second surface 2b of the web 2 opposite to the first surface 2a (that is, on the opposite side of the web

2) at a position such that the marking 6 is visible or detectable after the step of making the corresponding article 1. Advantageously, therefore, it is possible to ensure that the marking 6 is made on a portion of the web 2 which is not covered or surmounted by other elements when the article 1 is completed.

In a possible embodiment not illustrated, however, the marking 6 might be made on the same surface 2a, 2b of the web 2 which the feature 4a and/or the additional item 4b is applied on.

According to a further aspect of the invention, between the step of applying the feature 4a and/or the additional item 4b to the web 2 and the step of making the succession of articles 1 using the web 2 there is preferably a step of temporarily storing a stretch of the web 2 in a buffer "B", the length of the stretch of web 2 in the buffer "B" being variable over time. Still more preferably, the buffer "B" is of the "pendulum" or movable roller type.

Between the step of applying the feature 4a and/or the additional item 4b to the web 2 and the step of making the succession of articles 1 using the web 2 there is also, preferably, a step of tensioning the web 2 (for example, by means of dancer rollers) which results in non-uniform feed of the web 2 and which can thus alter the longitudinal reference of the web 2. Applying the markings 6, therefore allows precisely detecting the presence of defects, if any, even if the longitudinal reference of the web 2 has been altered.

Figures 2, 3A, 3B, 4 illustrate an example embodiment of a web 2 used for making connecting strips 7 and of an article 1 comprising the connecting strip 7.

In this example embodiment, the step of making the succession of articles 1 using the web 2 preferably comprises the following sub-steps:

- cutting the web 2 into a plurality of connecting strips 7, each connecting strip 7 comprising at least one application zone 5,

- rolling each connecting strip 7 round a respective group of segments of the tobacco industry in such a way as to make an article 1 , each group preferably comprising at least one filter segment 8 and at least one cigarette segment 9, wherein the marking 6 is disposed on a surface of the connecting strip 7 facing the outside of the article 1 at a position where it is visible or detectable from the outside.

Still more preferably, the application zone 5 is disposed on the surface of the connecting strip 7 facing the inside of the article 1 and opposite to the surface with the marking 6 on it.

With reference to Figure 2, the method comprises a step of detecting the non presence of the additional item 4b (for example a label) in a specific application zone 5' and thus determining that the additional item 4b in that specific application zone 5' does not meet a criterion of acceptability (for example, position or colour).

Thus, the method comprises a step of applying a marking 6 (in the example illustrated in Figures 3A-3B, the marking is a printed colour marker) on the second surface 2b of the web 2. In the specific case of the embodiment of Figure 3A, the marking 6 (a transverse stripe) is made in proximity to an edge of the area that will make the next connecting strip 7, whilst in the embodiment of Figure 3b, the marking 6 (an“X”) is made in the application zone 5'.

Figure 4 thus illustrates a defective article 1 made by rolling the connecting strip 7 (obtained from the web of Figure 3A) round the group comprising a filter segment 8 and a cigarette segment 9. The marking 6 is clearly visible on the article 1 illustrated in Figure 4 and will allow identifying the article 1 as a defective article to be rejected.

The presence of the marking 6 in this case represents the fact that a defect has been found on the inside of the connecting strip 7, which means that the article 1 must be rejected; in this specific case, no additional item 4b has been applied in the application zone 5 of the web 2 during the step of applying in which it should have been applied.

Alternatively, the step of making the succession of articles 1 using the web 2 preferably comprises the following sub-steps: - progressively wrapping the web 2 around a continuous stream of filter material or tobacco inside a forming beam in such a way as to make a continuous rod,

- cutting the continuous rod into a plurality of segments, each wrapped in a portion of web 2 comprising at least one application zone 5, where the marking 6 is disposed on an outward facing surface of the portion of web 2 at a position where it is visible or detectable from the outside. Still more preferably, the application zone 5 is disposed on the surface of the portion of web 2 facing the stream of material and opposite to the surface with the marking 6 on it.

It is thus possible, for example, to apply the method of this invention to the production of filter segments 8 or of cigarette segments 9.

In a possible alternative embodiment of the method of this invention, the step of making a succession of articles 1 using the web 2 comprises a sub-step of forming a multilayer, tubular cylindrical rod comprising at least two layers, of which the first layer is defined by the web 2, followed by a sub-step of cutting the multilayer, tubular cylindrical rod into individual segments.

More specifically, the sub-step of forming a multilayer, tubular cylindrical rod can be carried out by superposing at least the first layer and a second layer, in which the first layer is radially disposed on the outside of the second layer and in which a first surface 2a of the web 2 which comprises the application zone 5 defines an inside face of the first layer facing the second layer and in which the marking 6 can be made on the second surface 2b of the web 2 defining the outside face of the first layer.

Lastly, described with reference to Figure 1 is an example embodiment of a plant 100 for making rod-shaped articles 1 , where the web 2 is used to make the connecting strips 7.

The plant 100 comprises:

- conveyor means 101 , 102 configured to feed a succession of groups, not illustrated, along a first path, each group preferably comprising at least one filter segment 8 and at least one cigarette segment 9, both disposed transversely to the first path;

- feed means 103 for feeding the web 2 configured to cause the web 2 to advance along a second path;

- an applicator device 104 disposed along the second path and configured to apply the feature 4a and/or the additional item 4b on the web 2 in the application zone 5 of the web 2, preferably on the first surface 2a of the web 2;

- a first detecting device 105 disposed downstream of the applicator device 104 along the second path and configured to detect the presence and/or at least one property of the feature 4a and/or of the additional item 4b in the application zone 5;

- a control unit 106 configured to determine whether the feature 4a and/or the additional item 4b in the application zone 5 meets at least one criterion of acceptability;

- a marking device 107 disposed downstream of the first detecting device 105 along the second path and, on command from the control unit 106 if the criterion of acceptability is not met, configured to apply the marking 6 in the application zone 5 of the web 2 or within a predetermined distance from the application zone 5, preferably on the second surface 2b of the web 2 opposite to the first surface 2a;

- a cutting device 108 disposed downstream of the marking device 107 and configured to cut the web 2 into a plurality of connecting strips 7, each connecting strip 7 comprising at least one application zone 5;

a rolling bed 109 adapted to receive the succession of groups and the plurality of connecting strips 7 and configured to roll the plurality of connecting strips 7 round the respective groups to make a plurality of articles 1 , where a first surface of the connecting strip 7 comprising the application zone 5 defines an inside face of the connecting strip 7 facing the group;

- a second detecting device 110 connected to the control unit 106, disposed downstream of the rolling bed 109 and configured to identify the articles 1 with the markings 6 on them and to activate a procedure for rejecting the articles 1 with the markings 6;

- a rejection device 111 configured to reject the plurality of articles 1 , the articles 1 being those on which the presence of the marking 6 has been detected.

Advantageously, the marking device 107, the first detecting device 105 and the second detecting device 110 allow detecting the defects on the web 2, marking the defective portion of the web 2 and causing the defective articles 1 to be rejected.

The present invention achieves the preset aims and overcomes the disadvantages of the prior art by creating a physical one-to-one match between the defective application zone and the corresponding article 1 which includes it (and which must therefore be rejected). This match is independent of the machine's operating variables (speed, web tension, presence of buffer, etc.) making it possible to precisely and effectively select only the defective articles at all times, without having to reject good products on account of uncertainty.

Moreover, detecting defects on the web 2 before making the article 1 is easier and more precise than detecting them on a finished, cylindrical article (which would require expensive and complex detecting systems). This allows higher efficiency in terms of detecting truly defective products or semi-products, avoiding the risks of false positives or non-detection of defects.

Advantageously, the invention can be applied not only to reject defective semi-products before they are processed to become part of the finished product but also the finished products themselves after they have been made.

The proposed invention is equally applicable to detecting web defects even where no features 4a or additional items 4b need be applied, which means that articles 1 containing defective portions of web 2 can be rejected. In this case, the step of detecting is intended to determine the absence of defects on the starting web 2.

The invention can also be carried out by applying a marking 6 on the inside of the article 1 (that is to say, on an inward facing surface of the web) whether the application zone faces the inside or the outside. In this situation, it may be advantageous to make the marking 6 in such a way that it can be detected by non-optical systems: for example using metallic material or radio-opaque material for detection by flow-through radiation detectors.