WO2026028232A1

WO2026028232A1 - Glue applicator unit and corresponding method for applying glue to smoking article elements

Info

Publication number: WO2026028232A1
Application number: PCT/IT2025/050177
Authority: WO
Inventors: Antonio Caporale; Luca Galletti
Original assignee: IMA Industria Macchine Automatiche SpA
Current assignee: IMA Industria Macchine Automatiche SpA
Priority date: 2024-07-31
Filing date: 2025-07-30
Publication date: 2026-02-05
Anticipated expiration: 2027-01-31

Abstract

The invention concerns a glue applicator unit (10), comprising a glue storage tank (31) which is equipped with a glue distributing roller (32) inside it, and a glue applicator member (21) movable between the storage tank (31) and a station (101) for applying glue to a smoking article element. The invention also concerns a corresponding method for applying glue to smoking article elements.

Description

“GLUE APPLICATOR UNIT AND CORRESPONDING METHOD FOR APPLYING GLUE TO SMOKING ARTICLE ELEMENTS”

* * * * *

FIELD OF THE INVENTION

The present invention concerns a glue applicator unit for applying glue to smoking article elements, and a corresponding glue application method. Specifically, the elements are sheets of paper or suchlike, for closing smoking articles longitudinally.

BACKGROUND OF THE INVENTION

Apparatuses for producing smoking articles, such as cigarettes or suchlike, equipped with a glue applicator unit to longitudinally close the sheet of paper that wraps the tobacco, have long been known.

Known units comprise a tank holding the glue, located below a paper closing station. An applicator member is provided between this station and the tank, which translates vertically and is equipped with a pad that physically applies the glue to the paper. In particular, the pad contacts the paper and the relative movement between them causes a strip of glue to be deposited.

In order to have an adequate amount of glue on the section, the vertical translation movement of the applicator member provides that, in a loading position of the pad, this is completely immersed in the glue for a short period of time and then immediately extracted therefrom so as to return, after a vertical translation movement, toward the closing station.

A disadvantage of this known solution is that the repeated immersions and extractions of the applicator member in/from the glue causes the glue to incorporate a certain amount of air, which causes the formation of bubbles and sometimes even foam in the glue, which prevent the glue from being applied homogeneously on the entire length of the paper. In addition, the bubbles and foam decrease the gluing capacity because, for the same amount of glue deposited on the sheet, the adhesive amount is lower than expected due to the presence of air.

Another disadvantage is that this type of solution causes considerable dirt, caused by glue dripping from the applicator member.

Another disadvantage is that the amount of glue that can be applied to the paper is a function of the thickness of the pad and the time that passes between the exit of the pad from the tank and the moment it touches the sheet. This entails considerable problems of adjusting the speed of movement of the pad in order to obtain a certain thickness of the strip of glue on the sheet.

To overcome these problems, a known solution provides to resort to guns that deliver glue points on the sheet, as disclosed for example by US-B 1-6463716. However, this solution does not fully meet the expectations of the industry, since the strip of glue that is obtained does not have a defined shape and therefore creates problems with the gluing’s reliability.

Other solutions, known from documents US4252527, GB-A-2537349, US-A1- 2017/0238602 and US-A-6063016 among others, provide the presence of a loading roller arranged in the glue tank, which the applicator member contacts cyclically to pick up a certain amount of glue. This allows to avoid immersing the applicator member in the glue, but has the disadvantage of providing, as an applicator member, another roller, so as to be able to conveniently orient the amount of glue picked up toward the sheet closing station. The transfer of glue from the roller arranged in the tank to the applicator roller takes place by means of a movement of the latter that is tangential with respect to the surface of the roller arranged in the tank. This leads to problems of repeatability of the amount of glue picked up, and therefore applied onto the sheet. In addition, the applicator rollers do not allow to apply the glue precisely, and therefore obtain a well-defined strip of glue on the sheet.

There is therefore the need to perfect a glue applicator unit and a corresponding method for applying glue to smoking article elements that can overcome at least one of the disadvantages of the state of the art.

To do this, it is necessary to resolve the technical problem of providing a glue applicator unit capable of applying a strip with defined sizes and thicknesses, corresponding to the those desired, regardless of the applicator member’s speed of movement.

In particular, one purpose of the present invention is to provide an applicator unit and develop a method for applying glue to smoking article elements able to always apply the same amount of glue uniformly.

Another purpose of the present invention is to provide an applicator unit and develop a method for applying glue to smoking article elements that allow to avoid any dirt caused by glue spreading in the vicinity of the closing station.

Another purpose of the present invention is to provide an applicator unit and develop a method for applying glue to smoking article elements that allow the amount of glue to be independent of the applicator member’s speed of movement.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.

In accordance with the above purposes and to resolve the technical problem described above in a new and original way, also achieving considerable advantages compared to the state of the prior art, a glue applicator unit according to the present invention includes a storage tank configured to hold glue, a glue distributing roller rotatably mounted about an axis of rotation within the glue storage tank so as to be partially immersed in the glue, and a glue applicator member comprising a pad. Advantageously, the smoking article element is a sheet of paper, intended to be rolled up to delimit a zone of the smoking article that comprises tobacco or other smokable material.

In accordance with one aspect of the present invention, the applicator member is configured to perform a radial approaching movement with respect to the distributing roller.

Favorably, the glue applicator unit comprises a handling mechanism supporting the applicator member. This handling mechanism is configured to move the applicator member, in particular the pad, along an advancement path between a glue pick-up position, in which the pad contacts the distributing roller in a direction substantially radial to the axis of rotation in order to pick up glue from a surface of the distributing roller, and a glue application position, in which the pad contacts the smoking article element at a glue application station to apply the glue to the smoking article element. Advantageously, the handling mechanism comprises an epicyclic mechanism system, specifically an epicyclic gear.

Doing so achieves at least the advantage of having a glue applicator unit that prevents the applicator member from picking up an excessive amount of glue from the distributing roller. In addition to preventing any dirt caused by an excess of glue dripping from the applicator member, this allows to have a uniform and complete amount of glue on the latter, in particular on the pad, which allows to obtain a strip of glue on the sheet that is complete and defined in its shape, and corresponds to the desired sizes and thicknesses.

In accordance with another aspect of the present invention and with the above purposes, and also to resolve the technical problem described above in a new and original way, also achieving considerable advantages compared to the state of the prior art, a method according to the present invention for applying glue to smoking article elements by means of a glue applicator unit comprises the steps of providing a storage tank containing glue; rotatably mounting a glue distributing roller in the storage tank about an axis of rotation, such that the glue distributing roller is partially immersed in the glue; picking up glue from a surface of the glue distributing roller by means of a pad of an applicator member; applying the glue to a smoking article element arranged at a glue application station.

During the picking up step, the pad is brought into contact with the glue distributing roller by performing a movement along a direction substantially radial with respect to the glue distributing roller.

Preferably, the method is executed by means of the glue applicator unit as disclosed above.

DESCRIPTION OF THE DRAWINGS

These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 is a front view of a glue applicator unit according to the present invention;

- fig. 2 is a three-dimensional view of a glue storage tank of the glue applicator unit of fig. 1;

- fig. 3 is a three-dimensional view of a glue applicator device of the glue applicator unit of fig. 1;

- fig. 4 is a front view of the glue applicator unit of fig. 3, which visualizes a trajectory of the glue applicator device;

- fig. 5 is a plan view of the glue applicator unit and of a part of an apparatus for producing smoking articles which comprises the applicator unit;

- fig. 6 is a front view of a glue applicator unit according to a variant of the present invention;

- fig. 7 is a three-dimensional view of a cleaning unit comprised in the glue applicator unit of fig. 6;

- fig. 8 is a front view of the glue applicator unit, which visualizes the possible trajectories of the glue applicator device; and

- fig. 9 is a three-dimensional view of a variant of the cleaning unit of fig. 7.

We must clarify that the phraseology and terminology used in the present description, as well as the figures in the attached drawings also in relation as to how described, have the sole function of better illustrating and explaining the present invention, their purpose being to provide a non-limiting example of the invention itself, since the scope of protection is defined by the claims.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications.

DESCRIPTION OF SOME EMBODIMENTS

With reference to fig. 1, a glue applicator unit 10 according to the present invention is provided in an apparatus 100 for producing smoking articles which includes a glue application station 101 at which the glue is applied onto smoking article elements, in particular on thin paper sheets configured to be rolled around a respective longitudinal axis thereof so as to form a smoking article, or a precursor product of a smokable element.

The glue application station 101 comprises an abutting surface 102 oriented toward the applicator unit 10 and against which the thin paper sheets are held by suction, or by means of mechanical members (fig. 1). The thin paper sheets are fed to the abutting surface 102 laterally. The latter has a longitudinal axis A (fig. 5) perpendicular to the feeding direction of the thin paper sheets.

The apparatus 100 also comprises a control unit 103, schematized in fig. 3, which is configured to control the different components and the different operating stations of the apparatus 100, including the applicator unit 10.

The applicator unit 10 comprises a glue applicator device 20 and a glue pick-up station 30 equipped with a glue storage tank 31.

The applicator device 20 comprises a glue applicator member 21 and a corresponding handling mechanism 22 that supports the applicator member 21 (figs. 1 and 3). In particular, the applicator member 21 comprises a pad 23, in turn comprising an applicator shank 23A equipped with an applicator edge 24, in particular rectilinear or substantially rectilinear. The surface of the applicator edge 24 is advantageously flat, so as to apply a continuous strip of glue.

Since the pad 23 is provided with a rectilinear applicator edge 24, it is configured to apply the glue forming a rectilinear strip on the thin paper sheets, with sizes substantially equal to the applicator edge 24.

Inside it, the storage tank 31 is provided with a glue distributing roller 32, mounted during use so as to be partially immersed in an amount of glue present in the storage tank 31 (fig. 2). The distributing roller 32 is rotatable about an axis of rotation Rl, which is advantageously substantially parallel to the surface of the glue when it is idle, that is, the axis of rotation Rl is substantially horizontal.

In this way, the distributing roller 32, when set in rotation, has its surface that is not immersed in the glue covered by a substantially homogeneous film of glue.

In the example shown, the storage tank 31 is covered by a lid 33 equipped with an access window 34, with sizes such as to allow the passage of the applicator member 21 of the applicator device 20. In particular, the sizes of the window 34 are larger than the sizes of the applicator edge 24 of the pad 23, allowing the latter to be inserted in the window 34.

The window 34 has a substantially rectangular shape and extends along a longitudinal axis A2 thereof, which is parallel to the axis of rotation Rl of the roller 32 (fig. 2). The pad 23, in particular the applicator shank 23 A, also extends parallel to these two axes. The applicator edge 24 has to at least be parallel to these two axes, at least when it is at the storage tank 31, advantageously even in its vicinity.

The applicator device 20 is also rotatably mounted about a corresponding axis of rotation R2, which is parallel to the axis of rotation Rl of the distributing roller 32 and the longitudinal axis A2 of the window 34.

With regard to the applicator device 20, the applicator member 21 comprises a corresponding rod 25 on which the pad 23 is fixed. In particular, the pad is located longitudinally to the rod 25 and extends radially therefrom (fig. 3). The rod 25 is oriented parallel to the axis of rotation R2.

The applicator device 20 also comprises a central shaft 26 located coaxially to the axis of rotation R2 and connected, at a first end 26A thereof, to the handling mechanism 22. In the example shown in the drawings, the central shaft 26 is equipped, at its second end 26B, with a radially extending connection arm 27, which is connected to the rod 25. The connection is rotatable, that is, the rod 25 is rotatable with respect to the arm 27.

The handling mechanism 22 is configured to displace, or move, the applicator member 21 along an advancement path so that it has a trajectory of approach to the storage tank 31 that is radial, or substantially radial, with respect to the axis of rotation R1 of the distributing roller 32. In particular, always when approaching the storage tank 31, the pad’s 23 trajectory of approach to the storage tank 31 is such that it is oriented radially with respect to the axis of rotation Rl, and therefore also to the distributing roller 32.

The handling mechanism 22 is an epicyclic mechanism, in particular an epicyclic gear system (figs. 3 and 4).

A gear system is understood as a system of toothed wheels that mesh with each other so that the movement of one of them, in particular the driving wheel, causes a movement of the others, also called driven wheels. An epicyclic gear system is understood as a gear system in which at least one of the toothed wheels has a movable axis.

The handling mechanism 22 comprises a first toothed wheel 221, also called a sun gear, with which a second toothed wheel 222, also called a planet gear, is engaged. It can be inferred that the second toothed wheel 222 is movable with respect to the first toothed wheel 221, in particular it is movable around it. The first toothed wheel 221 is instead rotatable about its own axis of rotation, which is fixed in the applicator unit 10. A third toothed wheel 223 is located between these two toothed wheels 221, 222, being engaged with both the first toothed wheel 221 and also the second toothed wheel 222.

The first toothed wheel 221 is coaxial with the central shaft 26 and, remaining stationary during the rotation of the mechanism 21, makes the characteristic desired trajectory of the pad 23, and in particular of its end 24, possible. The central shaft 26 is therefore the shaft that commands the movement of the epicyclic gear system. For this purpose, the central shaft 26 is connected to a drive member M (schematized in figs. 1 and 5) controlled by the control unit 103, in particular it is aligned with a drive shaft Ml exiting from the drive member M. Preferably, the first toothed wheel 221 is fixed to the static part of the unit 20.

The second toothed wheel 222 is coaxial with the applicator member 21, in particular with the rod 25. The connection arm 27 between the central shaft 26 and the rod 25 acts as a planet carrier.

The epicyclic gear system is configured as a reducer, that is, the angular speed of the rod 25 is greater than the angular speed of the central shaft 26. In the example shown, the first toothed wheel 221 has the largest diameter of the three toothed wheels, while the second toothed wheel 222 has the smallest diameter of the three wheels.

Thanks to this handling mechanism 22, the applicator edge 24 of the applicator member 21 follows a trajectory Tl (figs. 4 and 8) between the glue application station 101 and the storage tank 31, more precisely between the glue application station 101 and the distributing roller 32, the ends of which are perpendicular, or substantially perpendicular, with respect to the abutting surface 102 of the glue application station 101 on one side, and radial, or substantially radial, to the distributing roller 32, as well as to its axis of rotation Rl, on the other side. That is, the pad 23 is configured to apply the glue according to a direction substantially perpendicular to the abutting surface 102.

This allows to have, at both ends of the trajectory Tl, the applicator edge 24 arriving at and contacting the distributing roller 32 and the abutting surface 102, respectively, substantially parallel to the axes Rl and R2, so that when it picks up the glue, the latter is spread over its entire surface, while when it applies or deposits the glue, all the glue present on it is involved.

The trajectory Tl of the applicator member 21 is shown schematically in fig. 4. This trajectory defines, at its ends, a direction of contact Cl with the glue application station 101 and a direction of contact C2 with the storage tank 31, which correspond to the orientation of the applicator member 21, in particular of the pad 23, when it contacts the abutting surface 102 and the distributing roller 32, respectively (fig. 4). These two directions are centered on the axis of rotation R2 of the applicator device 20. Advantageously, these two directions form an angle equal, or substantially equal, to 120° between them. Since the glue application station 101 is positioned above the applicator device 20, the distributing roller 32 is placed laterally and below the applicator device 20, in this case to the bottom left.

The applicator device 20 and the storage tank 31 are fixed to a common support element 40 which is movable with respect to the apparatus 100 in which the applicator unit 10 according to the present invention is provided. In particular, the axis of rotation R2 of the applicator device 20 can be inclined with respect to the orientation of the abutting surface 102, while remaining in a horizontal plane. This is shown in fig. 5, where it can be seen that the axis of rotation R2 is inclined, with an inclination that has been emphasized for reasons of clarity, in a substantially horizontal plane represented by the plane of the sheet, with respect to a longitudinal axis A of the abutting surface 102. Since the applicator device 20 and the storage tank 31 are fixed on a common support element 40, it can be deduced that they move together, and therefore that the axis of rotation R2 remains parallel to the axis of rotation Rl.

In this way, there is the freedom to orient the applicator device 20, and therefore the applicator edge 24, according to the shape of the thin paper sheets on which to apply the glue, so that the strip of glue applied is substantially parallel to a lateral edge of the thin paper sheet.

For example, when producing classic, that is, cylindrical cigarettes, the thin paper sheets have a substantially rectangular shape, the applicator edge 24 can therefore remain substantially parallel to the orientation of the abutting surface 102. When, on the other hand, conical-shaped smoking articles are being produced, the lateral edges of the paper sheets are inclined, since the paper is substantially fan-shaped, which also requires tilting the applicator edge 24 with respect to the orientation of the abutting surface 102 so as to make it substantially parallel to the lateral edge of the thin paper sheets where the glue is being applied.

In the example shown, the support element consists of a vertical plate 41 and a horizontal plate 42, fixed to the vertical plate 41 perpendicularly. In particular, the applicator device 20, more precisely the first toothed wheel 221 and the central shaft 26, are fixed to the vertical plate 41, while the storage tank 31 is fixed to the horizontal plate 42 (figs. 1, 2 and 4). The operation of the applicator unit 10 described heretofore, which corresponds to the method according to the present invention, comprises the following steps.

- providing a storage tank 31 containing glue;

- mounting, rotatable about an axis of rotation Rl, a glue distributing roller 32 in the tank 31, the roller being partially immersed in the glue;

- picking up glue from a surface of the distributing roller 32 by means of the pad 23 of the applicator member 21 ;

- applying the glue onto a smoking article element, arranged at the glue application station 101.

In an optional step, it is provided to correctly orient the applicator unit 10 with respect to the apparatus 100, in particular with respect to the abutting surface 102, by adjusting the inclination of the applicator device 20. As mentioned above, this orientation of the applicator unit 10 substantially depends on the shape of the thin paper sheets on which to apply the glue, so that the strip of glue is parallel to a lateral edge of the thin paper sheets.

Once the apparatus 100, and therefore the feed of thin paper sheets onto the abutting surface 102, has been started, the applicator member 21 starts to move, in particular through the drive of the handling mechanism 22 of the applicator device 20.

A first step of moving the applicator member 21 toward the storage tank 31, which contains the distributing roller 32 therein, is provided, so that the applicator member 21 can pick up a dose of glue. This movement step provides a step of moving the applicator member 21 close to the distributing roller 32, in which the applicator member 21 follows a trajectory T1 having at least one segment, in particular the one closest to the roller, which is oriented substantially radial to the distributing roller 32 and its axis of rotation Rl. That is, the pad 23 contacts the glue distributing roller 32 by a movement along a direction substantially radial with respect to the distributing roller 32.

More precisely, because of the epicyclic gear system described above, the pad 23 approaches the distributing roller 32 oriented substantially radial thereto, with the applicator edge 24 oriented toward it. In this way, the applicator edge 24 contacts the distributing roller 32 with its entire surface, which optimizes the pickup of glue from the distributing roller 32. Subsequently, always by means of the handling mechanism 22, a second movement of the applicator member 21 is performed, from the storage tank 31 toward the glue application station 101. In particular, the second movement follows the same trajectory T1 as the first movement, but in the opposite direction (fig- 4).

This second movement ends with a sub-step of approaching the applicator member 21 to the abutting surface 102, in which the applicator member 21, in particular the pad 23, moves perpendicularly or substantially perpendicularly to the abutting surface 102. Obviously, in this step the applicator edge 24 is oriented toward the abutting surface 102.

Subsequently, the applicator edge 24 contacts a predefined zone of the thin paper sheet, at the abutting surface 102, and applies a strip of glue thereto. The sizes of the strip of glue substantially correspond to the sizes of the applicator edge 24, thanks to the orientation of the pad 23, which is perpendicular or substantially perpendicular to the abutting surface 102, and therefore to the thin paper sheet, when it contacts it.

The steps of moving the applicator member 21 toward the storage tank 31 and toward the glue application station 101 are then repeated alternately while the thin paper sheets are fed in succession along the abutting surface 102.

With reference to figs. 6-8, according to a variant the applicator unit 10 comprises, in addition to what described above, a cleaning station 50, configured to clean the applicator member 21, in particular the pad 23, from any excess of glue that accumulates over time during the operation of the glue applicator unit 10. The cleaning station 50 is positioned downstream of the application station 101 and upstream of the glue pick-up station 30 along the advancement path of the handling mechanism 22, that is, of the pad 23.

The cleaning station 50 comprises a first cleaning roller 51 and a second cleaning roller 52 which, in the example shown in the drawings, are each equipped, on their entire lateral surface, with a plurality of cleaning members 500, in this case bristles regularly distributed on the lateral surface of the rollers 51, 52. It can be provided that the first 51 and second 52 cleaning roller have no bristles, or that only one of the two has them.

The cleaning members have a height H, with respect to the external surface of the rollers 51, 52. The first and second roller 51, 52 are positioned in such a way that, at the point where the distance between them is shortest, the distance between their surfaces is slightly greater than H, but in any case smaller than 2H, so that the cleaning members 500 of the two rollers 51, 52 can intertwine with each other. In other words, the axes of rotation R3, R4 of the two rollers 51, 52 are spaced by a distance equal to the diameter of the rollers, to which an additional distance is added, comprised between the height H of the cleaning members 500 and twice the same height H.

This point of shortest distance between the two rollers 51, 52 defines a seat 50A for cleaning the applicator member 21, in particular the pad 23.

The first and second roller 51, 52 are arranged in such a way that the applicator member 21, in particular the pad 23, approaches them in a direction tangential to each of them and between them, so that both their cleaning members 500 affect it simultaneously. This approach takes place at the cleaning seat 50A defined above.

The two cleaning rollers 51, 52 are located rotatable about respective axes of rotation R3, R4, parallel to the axes of rotation Rl, R2 as well as to the longitudinal axis A of the window 34 (fig. 6). Preferably, the first and second roller 51, 52 are driven in rotation so that their cleaning members brush the sides of the pad 23 from its base toward the applicator edge 24. The first and second cleaning rollers 51, 52 are counter-rotating.

The cleaning station 50 also comprises a third cleaning roller 53, also equipped with a plurality of cleaning members 501 on its lateral surface, in particular bristles, which have a height Hl which can be the same as or differ from the height H of the bristles 500.

The third cleaning roller 53 is positioned downstream of the first and second roller 51, 52 with respect to the applicator device 20, that is, it is behind the first two rollers 51, 52 with respect to the applicator member 21 when it is in the cleaning seat 50A. The third roller 53 is rotatable about its own axis of rotation R5, parallel to the axes of rotation R3, R4 of the first two cleaning rollers 51, 52.

The third roller 53 is positioned in such a way that its cleaning members 501 contact the cleaning members 500 of both the first 51 and also the second cleaning roller 52. In other words, the smallest distance between the third roller 53 and the first 51 and second cleaning roller 52 is comprised between the height H of the cleaning members 500 or the height Hl of the cleaning members 501, and the sum of their values, similarly to what explained above for the first two cleaning rollers 51, 52. In particular, the axis of rotation R5 of the third cleaning roller 53 is substantially parallel to the cleaning seat 50A defined between the first two rollers 51, 52.

The cleaning station 50 is positioned so that it can be reached by the applicator member 21 during its movement determined by the handling mechanism 22. In particular, the cleaning seat 50A is in a position in which the applicator member 21, in particular the pad 23, is oriented along a direction C3 of insertion into the cleaning station 50, in which the applicator member 21 is substantially tangential to both the first and also the second cleaning roller 51, 52. The direction C3 of insertion is also radial with respect to the third cleaning roller 53. This direction C3 of insertion is also centered on the axis of rotation R2 of the applicator device 20, and forms an angle of approximately 120° with the direction Cl of contact with the glue application station 101 and with the direction C2 of contact with the storage tank 31 (figs. 6 and 8).

The cleaning station 50 comprises, underneath the third cleaning roller 53, a tank 54 configured to hold a cleaning liquid, shown here filled with, for example, water. The third roller 53 is arranged so as to be partially immersed in the cleaning liquid. In this way, when the third cleaning wheel 53 is driven in rotation, it collects the cleaning liquid from the tank 54 and in the same movement brings it into contact with the cleaning members 500 of the first two cleaning rollers 51, 52 that come into contact with the applicator member 21. The third roller 53 is thus configured to clean the bristles of the first roller 51 and of the second roller 52, and the first two rollers 51, 52 are cleaned, removing any accumulations of glue therefrom that form over time.

The cleaning liquid is also transferred onto the first and second cleaning rollers 51, 52 and is then applied onto the applicator member 21. To prevent it from being wetted with the cleaning liquid when it comes to pick up the glue in the storage tank 31, the applicator unit 10 can comprise, underneath the applicator device 20, that is, between downstream of the cleaning station 50 and upstream of the glue pick-up station 30, along the advancement path of the handling mechanism 22, a drying station 60 for drying the applicator member 21, in particular the pad 23. The drying station 60 comprises a drying device 61. The latter is advantageously configured to eject a jet of air, preferably heated, of short duration but great power so as to dry the applicator member 21 during its movement between the cleaning station 50 and the storage tank 31. For example, the air jets can be under pressure of a few bars. The presence of the drying station 60 advantageously allows to dry the pad 23, so as to prevent the glue that the latter is about to pick up from the distributing roller 32 from diluting due to a possible liquid (water) with which it has come into contact in the cleaning station 50, and which remains on the pad 23.

The advantageous positioning of the cleaning station 50, relative to the glue application station 101 and the storage tank 31, means that the applicator member 21 can reach these three stations by means of the handling mechanism 22 (fig. 8). In particular, under the effect of this handling mechanism 22, the applicator member 21 follows, in addition to the trajectory Tl described above between the glue application station 101 and the storage tank 31, a second trajectory T2 between the glue application station 101 and the cleaning station 50, as well as a third trajectory T3 between the cleaning station 50 and the storage tank 31 (fig. 8). Depending on the direction in which the handling mechanism 22 is driven, the trajectories Tl, T2, T3 of the applicator member 21 can be travelled in both directions.

The ends of each of the trajectories Tl, T2, T3 are at the directions Cl, C2, C3 described above. At these positions, the applicator member 21, in particular the pad 23, is oriented along the corresponding direction Cl, C2, C3 with the applicator edge 24 oriented toward the corresponding station.

We must clarify that the cleaning station 50 is only used occasionally during normal operation of the applicator unit 10. It is therefore advantageously assembled on the support element 40, in particular the cleaning rollers 51, 52, 53 can be mounted on the vertical plate 41 , so as to be movable.

An example of movable assembly is shown in fig. 9, and provides that the cleaning station 50 is fixed to a support 55 thereof, in particular equipped with a vertical panel 55 A and a horizontal panel 55B, which is slidably mounted on the support element (fig. 9).

For this purpose, the support element 40 can contain a sliding rail 43 extending from the joint between the vertical plate 41 and the horizontal plate 42, in a horizontal direction. The support 55 of the cleaning station 50 is advantageously equipped with a rail counter-element 56 configured to be slidably associated with the sliding rail 43 (fig. 9). In this way, the cleaning station 50 is movable on rails 43, 56 between an operative position, in which it is approached to the handling mechanism 22 so as to enable the pad 23 to contact the first roller 51 and the second roller 52, and an inactive position, in which the cleaning station 50 is moved away or spaced from the handling mechanism 22 to prevent any interference with the pad 23 during the operation of the applicator unit 10.

Obviously, all the elements of the cleaning station 50 are connected to the support 55, including the tank 54 which is fixed to both the vertical panel 55 A and also the horizontal panel 55B.

Preferably, the vertical and horizontal panels 55 A, 55B have a shape, sizes and arrangement such as to be aligned with the vertical plate 41 and the horizontal plate 42, respectively, of the support element 40 when the cleaning station 50 is associated therewith.

The station can therefore be easily disassembled or moved when it is not needed, or to perform maintenance operations such as, for example, washing the rollers. In the case of a movable cleaning station 50, it is advantageous to provide that it is equipped with its own drive member, independent of the drive member M, which commands the movement of the station 50 approaching or away from the applicator member 21.

Furthermore, when it is provided to clean the applicator member 21, the control unit 103 is configured so as to provide a slowing down or a temporary stop in the feed of the thin paper sheets on which to apply the glue, thus allowing to perform a cleaning and drying cycle of the applicator member 21 without stopping the apparatus 100 and without generating paper sheets to be discarded because without glue.

From the point of view of the operation of this embodiment, and therefore of the method, a step of cleaning the applicator member 21 in the cleaning station 50 is provided, this cleaning step being carried out after the glue application step and before the glue pick-up step.

After the cleaning step, a step of drying the applicator member 21 by means of the drying device 61 is provided. It is clear that modifications and/or additions of parts or steps may be made to the applicator unit 10 and to the method as described heretofore, without thereby departing from the field and scope of the present invention, as defined by the claims. It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art will be able to achieve other equivalent forms of glue applicator unit and corresponding method for applying glue to smoking article elements, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby. In the following claims, the sole purpose of the references in brackets is to facilitate their reading and they must not be considered as restrictive factors with regard to the field of protection defined by the claims.

Claims

1. Glue applicator unit (10) comprising a glue pick-up station (30) including a glue storage tank (31) configured to hold glue, a glue distributing roller (32) rotatably mounted about an axis of rotation (Rl) within said glue storage tank (31) so as to be partially immersed in said glue, and a glue applicator member (21) comprising a pad (23), characterized by comprising a handling mechanism (22) supporting said glue applicator member (21) and configured to move the applicator member (21) along an advancement path between: a glue pick-up position, in which said pad (23) contacts said distributing roller (32) in a direction substantially radial to said axis of rotation (Rl) to pick up glue from a surface of said distributing roller (32), and a glue application position, in which said pad (23) contacts said smoking article element at a glue application station (101) to apply glue to the smoking article element.

2. Glue applicator unit (10) as in claim 1, characterized in that said pad (23) comprises an applicator shank (23 A) extending parallel to said axis of rotation (Rl) of the distributing roller (32).

3. Glue applicator unit (10) as in claim 1 or 2, characterized in that said handling mechanism (22) comprises an epicyclic gear system including a first driving toothed wheel (221) and a second driven toothed wheel (222) engaged with and rotatable about said first driving toothed wheel (221), and in that said pad (23) is mounted on a rod (25) fixed to said second driven toothed wheel (222).

4. Glue applicator unit (10) as in any of the preceding claims, characterized in that said application station (101) comprises an abutting surface (102) configured to support the smoking article element, and in that said pad (23) is configured to apply glue in a direction substantially perpendicular to said abutting surface (102).

5. Glue applicator unit (10) as in any of the preceding claims, characterized by further comprising a cleaning station (50) positioned downstream of the glue application station (101) and upstream of the glue pick-up station (30) along the advancement path of the handling mechanism (22), said cleaning station (50) being configured to clean the pad (23) of glue residues.

6. Glue applicator unit (10) as in the claim 5, characterized in that said cleaning station (50) comprises a first (51) and a second (52) counter-rotating cleaning roller defining a seat (50A) therebetween, the seat (50A) being configured to temporarily receive said pad (23) for cleaning.

7. Glue applicator unit (10) as in the claim 6, characterized in that at least one of said first (51) and second (52) counter-rotating cleaning rollers comprises bristles (500).

8. Glue applicator unit (10) as in the claim 7, characterized by further comprising a cleaning tank (54) configured to hold a cleaning liquid, and a third cleaning roller (53) rotatably mounted within said cleaning tank (54) so as to be partially immersed in the cleaning liquid and configured to clean the bristles (500) of said first and second cleaning rollers (51, 52).

9. Glue applicator unit (10) as in any of the claims 5-8, characterized in that said cleaning station (50) is movable along rails (43, 56) between an operative position, in which said cleaning station (50) is positioned to enable the pad (23) to contact said first (51) and second (52) cleaning rollers, and an inactive position, in which said cleaning station (50) is spaced from said handling mechanism (22) to prevent it from interfering with said pad (23) during operation.

10. Glue applicator unit (10) as in any of the claims 5-9, characterized by further comprising a drying station (60) positioned downstream of the cleaning station (50) and upstream of the glue pick-up station (30) along the advancement path of the handling mechanism (22), said drying station (60) being configured to dry the pad (23).

11. Glue applicator unit (10) as in the claim 10, characterized in that said drying station (60) comprises a drying device (61) configured to eject compressed air toward the pad (23).

12. Method for applying glue to smoking article elements by means of a glue applicator unit (10), said method comprising the following steps:

- providing a glue storage tank (31) containing glue;

- rotatably mounting a glue distributing roller (32) in the glue storage tank (31) about an axis of rotation (Rl), such that said glue distributing roller (32) is partially immersed in the glue;

- picking up glue from a surface of the glue distributing roller (32) by means of a pad (23) of an applicator member (21);

- applying the glue to a smoking article element arranged at a glue application station (101), characterized in that during said picking up step, said pad (23) is brought into contact with said glue distributing roller (32) by movement along a direction substantially radial with respect to said axis of rotation (Rl).

13. Method as in claim 12, characterized by further comprising a cleaning step wherein said applicator member (21) is cleaned in a cleaning station (50) of said glue applicator unit (10), said cleaning step being carried out after the glue application step and before the glue pick-up step.

14. Method as in claim 13, characterized by comprising, after said cleaning step and before the picking up step, a drying step wherein said applicator member (21) is dried by means of a drying device (61).