SYSTEM AND METHOD FOR APPLYING AN ADDITIVE TO AN AEROSOL-GENERATING SUBSTRATE FOR AN AEROSOL-GENERATING ARTICLE

Abstract

A system for applying an additive to an aerosol-generating substrate for an aerosol-generating article is provided, the system including: an aerosol-generating substrate, the aerosol-generating substrate being a sheet, a foil, or a web of aerosol-generating material; a reservoir containing an additive; an applicator roller configured to rotate around a rotational axis, the reservoir including a dispensing opening configured to dispense the additive to the applicator roller, the applicator roller being further configured to transfer the additive from the applicator roller to the aerosol-generating substrate by a rotational movement of the applicator roller around a rotational axis thereof and a relative movement of the aerosol-generating substrate with respect to the applicator roller in a conveying direction; and at least one backing roller, the at least one backing roller and the applicator roller being arranged to apply pressure from both sides to the aerosol-generating substrate.

Description

The present disclosure relates to a system for applying an additive to an aerosol-generating substrate for an aerosol-generating article and a method of producing an aerosol-generating substrate of an aerosol-generating article, where the aerosol-generating substrate comprises an additive.

Aerosol-generating articles not only refer to filter cigarettes and other smoking articles in which material is combusted to form smoke, but also those articles that generate an aerosol from an aerosol-generating substrate without requiring combustion thereof. Such articles are often designated as “heat-not-burn” aerosol-generating articles, since an aerosol-generating substrate is heated to a relatively low temperature to induce the formation of an aerosol but prevent the combustion of material contained within the aerosol-generating substrate.

Aerosol-generating articles are available in flavored varieties. Flavoring an aerosol-generating article may be achieved by incorporating flavoring additive in the aerosol-generating substrate. It is known to apply additive, in particular flavoring additive, on an aerosol-generating substrate for an aerosol-generating article by means of a spraying nozzle. The spraying nozzle produces a spray of additive liquid droplets. The additive liquid droplets are projected and deposited on the aerosol-generating substrate.

The application of additive, in particular of a flavoring additive, is an important requirement for the user experience, because it may have an impact on both the smoking experience and the appearance of the aerosol-generating article.

According to a first aspect of the present invention, there is provided a system for applying an additive to an aerosol-generating substrate for an aerosol-generating article. The system comprise an aerosol-generating substrate. The system comprises a reservoir. The reservoir contains an additive. The system comprises an applicator roller adapted to rotate around a rotational axis. The reservoir comprises a dispensing opening to dispense the additive to the applicator roller. The applicator roller is configured to transfer the additive from the applicator roller to the aerosol-generating substrate by a rotational movement of the applicator roller around its rotational axis and a relative movement of the aerosol-generating substrate with respect to the applicator roller in a conveying direction. The system further comprises a conveyor device. The conveyor device is configured to convey an aerosol-generating substrate in conveying direction with respect to the applicator roller.

According to another aspect of the present invention, there is provided a system for applying an additive to an aerosol-generating substrate for an aerosol-generating article. The system may comprise an aerosol-generating substrate. The system may comprise a conveyor device. The conveyor device may be configured to convey an aerosol-generating substrate in a conveying direction. The system may comprise a reservoir. The reservoir may contain an additive. The system may comprise an applicator roller. The applicator roller may be adapted to rotate around a rotational axis. The reservoir may comprise a dispensing opening to dispense the additive to the applicator roller. The applicator roller may be configured to transfer the additive from the applicator roller to the aerosol-generating substrate by a rotational movement of the applicator roller around its rotational axis. The applicator roller may be configured to transfer the additive from the applicator roller to the aerosol-generating substrate by a relative movement of the aerosol-generating substrate with respect to the applicator roller in a conveying direction.

In particular, the system may be adapted such that the aerosol-generating substrate moves in the conveying direction with respect to the applicator roller being stationary.

In comparison to spraying application, the application of an additive by means of a roller allows reducing the exposure time of the additive with the environmental air. When the additive is a flavor compound containing menthol for instance, reducing its exposure to environment air allows avoiding the volatilization and the crystallization of the menthol. Still in comparison to spraying application, the application by means of a roller reduces the diffusion of particles of additive in the air. At least 90%, more in particular 98% of the additive may be directly applied to the aerosol-generating substrate. In contrast, in prior art spraying applications, a significant portion of the additive does not reach the substrate, but contaminates adjacent machinery. Thus, contamination of components adjacent to the aerosol-generating substrate may be reduced or prevented. Hence, the application of an additive by means of an applicator roller may reduce the necessary cleaning effort. It may improve the availability of the production line, as the occurrence of production stoppages for maintenance purposes may be reduced. It may allow preventing waste of additive because at least 90%, more in particular 98% of the additive is applied to the aerosol-generating substrate. Clogging of the nozzle used for spraying the additive, especially when the additive contains menthol, may advantageously be avoided. The system may be free of pumps for the additive, in particular downstream of the reservoir. In prior art systems, a pump required for spraying may be subject to clogging, in particular due to crystallization of menthol.

Moreover, the applicator roller makes it possible to apply the additive at a well-defined position on the aerosol-generating substrate. In fact, the position of the dispensing opening with respect to the applicator roller and the aerosol-generating substrate allows applying the additive on the aerosol-generating substrate in a particular location. The additive may be applied to the aerosol-generating substrate so as to be delimitate a region of the aerosol-generating substrate comprising the additive from another region of the aerosol-generating substrate devoid of additive more precisely than by spraying. The width of the additive applied on the aerosol-generating substrate may be more accurately controlled than by in the prior art spraying applications because the application is independent from the number of droplet per unit of volume and the droplet size distribution. The amount of additive may be adapted such that the additive remains within the aerosol-generating substrate without diffusing to a wrapper of the aerosol-generating article. Staining of the wrapper of the aerosol-generating article may be prevented. The user experience may be improved. The application of additive on the aerosol-generating substrate by means of a roller allows improving the accuracy of the quantities of additive per article, thereby preventing inconsistences in quantities that could be felt by user during the smoking experience.

The aerosol-generating article may be an aerosol-generating article for producing an aerosol comprising an aerosol-generating substrate that is intended to be heated rather than combusted in order to release volatile compounds that can form an aerosol.

The aerosol-generating substrate may be a substrate capable of releasing upon heating volatile compounds, which can form an aerosol. The aerosol generated from aerosol-generating substrates may be visible or invisible and may include vapors (for example, fine particles of substances, which are in a gaseous state) as well as gases and liquid droplets of condensed vapors.

The aerosol-generating substrate may be a sheet, a foil or a web of aerosol-generating material. The aerosol-generating substrate may be a laminar substrate. The aerosol-generating substrate may have a width and length substantially greater than the thickness of the substrate. The aerosol-generating substrate may have a thickness comprised between 0.110 millimetres and 0.380 millimetres, in particular between 0.170 and 0.270 millimetres.

The aerosol-generating substrate may be a homogenized sheet of tobacco, in particular for the manufacture of aerosol-generating articles. The aerosol-generating substrate may comprise comprises humectants The aerosol-generating substrate may comprise comprises aerosol formers, such as polyhydric alcohols, such as propylene glycol, triethylene glycol, 1,3-butanediol and glycerine; esters of polyhydric alcohols, such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate. The aerosol-generating substrate may comprise at least 3% per weight, in particular at least 5%, and more in particular at least 10% per weight, of aerosol former with respect to the weight of the aerosol-generating substrate.

The aerosol-generating substrate may comprise plant-based material. The aerosol-generating substrate may be a material containing alkaloids. The alkaloid may comprise nicotine. The aerosol-generating substrate may be tobacco. Instead or in addition to tobacco, other plant-based materials may be part of the aerosol-generating substrate. Alternatively, the aerosol-generating substrate may be homogenized sheet of non-tobacco. The aerosol-generating substrate a fiber-based material, preferably a plastic fiber-based material, more preferably a biodegradable fiber-based material, more preferably cotton, more preferably cellulose. The aerosol-generating substrate may be a polylactic acid substrate. The aerosol-generating substrate may comprise acetate.

The aerosol-generating substrate may be crimped after or prior to the application of the additive. The aerosol-generating substrate may have a plurality of corrugations. Corrugations may comprise ridges or protrusions. Corrugations may comprise troughs or recesses. The corrugations are formed by ridges and recesses or ridges or recesses. A width of the ridges may be defined as a first distance between two peaks of the consecutive recesses. A width of the recesses may be defined as a first distance between two peaks of the consecutive ridges. A distance between a peak of the ridge and a peak of the recesses may define a height of the ridges or recesses.

The aerosol-generating substrate may be adapted to be converged or folded into a segment or rod-shape to form part of an aerosol-generating article.

The additive may be at least partially absorbed into the aerosol-generating substrate. The additive may comprise at least one flavoring component. The flavoring component may be natural or artificially based. The flavoring component may comprise natural or synthetic menthol.

The additive may comprise essential oil. The additive may comprise allyl hexanoate, benzyl alcohol, citral, ethanol, itsea cubeba oils, lemon oil, lime oil, L-menthol, menthol, orange oils sweet, orange oil terpeneless, orange oil terpenes, tangerine oils terpene-free, or a combination thereof. The additive may be an aerosol former such as glycerin. The additive may be an active ingredient, in particular alkaloid, such as nicotine.

The system may comprise a conveyor device configured to convey an aerosol-generating substrate in a conveying direction. The conveyor device may actively drive the aerosol-generating substrate in a conveying direction or passively guide the aerosol-generating substrate in a conveying direction. The conveyor device may comprise a conveyor belt, or several conveyor belts. In particular, the aerosol-generating substrate may be conveyed in between an upper or lower conveyor belt. The conveyor device may comprise a conveyor roller, or several conveyor rollers. In particular, the aerosol-generating substrate may be conveyed in between an upper or lower conveyor rollers. The applicator roller may form the conveyor roller or one of the conveyor rollers.

The system may comprise at least one further roller, in addition to the applicator roller. The system may further comprise at least one intermediate roller arranged between the reservoir and the applicator roller. The at least one intermediate roller may be configured for transferring the additive dispensed from the dispensing opening of the reservoir to the applicator roller. The presence of one or more intermediate rollers allows enhancing the distribution of the additive and the desired quantity of the additive on the applicator roller. The gap between the applicator roller and the at least one intermediate roller may be adjusted, so that the quantity of the additive can be adjusted. The at least one intermediate roller may be a metering roller. The metering roller allows further enhancing the distribution of the additive and the desired quantity of the additive on the applicator roller. The gap between the applicator roller and the metering roller may be adjusted, so that the quantity of the additive can be adjusted. The adjustment of the gap between the applicator roller and the metering roller may take into consideration the viscosity of the additive. The metering roller may comprise a thread portion. The metering roller may have a plurality of corrugations. Corrugations may comprise ridges or protrusions. Corrugations may comprise troughs or recesses. The corrugations are formed by ridges and recesses or ridges or recesses. A width of the ridges may be defined as a first distance between two peaks of the consecutive recesses. A width of the recesses may be defined as a first distance between two peaks of the consecutive ridges. A distance between a peak of the ridge and a peak of the recesses may define a height of the ridges or recesses. The metering roller may comprise a thread portion. The metering roller may be integrally formed. The metering roller may comprise a core segment. The core segment may be a cylindrical rod. The core segment may be made of metal, in particular of steel. At least one wire, in particular a steel-wire, may be wrapped around the core segment. The at least one wire may be wrapped around the core segment such that the resulting spires of the wire are transversal to a longitudinal axis of the core segment. The at least one wire may be wrapped tightly around the core segment such that the wire is in surface contact with a surface of the core segment. Alternatively, the metering roller may be a wire-wound metering rod, also known as Mayer rod. The metering roller may be in a distance to the aerosol-generating substrate. The applicator roller may be in contact with the additive applied on the aerosol-generating substrate.

The system may comprise at least one backing roller. The at least one backing roller and the applicator roller may be arranged to apply pressure from both sides to the aerosol-generating substrate. The backing roller may form the conveyor roller or one of the conveyor rollers.

The aerosol-generating substrate may be conveyed to the applicator roller in the conveying direction. Downstream of the applicator roller with respect to the conveying direction or downstream of the application of additive on the aerosol-generating substrate by means of the applicator roller, the aerosol-generating substrate comprising the additive may be conveyed along a downstream direction. The conveying direction may be aligned or parallel to the downstream direction. This may allow facilitating the design and the implementation of the production line. Alternatively, the conveying direction may be inclined with respect to the downstream direction, in particular by an inclination angle comprised between 5 degrees and 60 degrees, in particular between 30 degrees to 50 degrees. The inclination angle may be defined in relation to the convexity of the external surface of the applicator roller. A part of the aerosol-generating substrate before the applicator roller may be inclined with respect to the downstream direction. In this inclined configuration, a greater length of the aerosol-generating substrate may be wound around and brought into contact with the applicator roller than in a configuration wherein the conveying direction is parallel to the downstream direction. This may help stabilizing the quantity of additive deposited on the aerosol-generating substrate and increasing the deposition consistency. It also increases the quantity of additive deposited on the aerosol-generating substrate.

In an opposite inclined configuration, a smaller length of the aerosol-generating substrate may be wound around and brought into contact with the applicator roller than in a configuration wherein the conveying direction is parallel to the downstream direction.

The system may further comprise at least two applicator rollers with a respective rotational axis. The respective rotational axis of the at least two applicator rollers may be coincident with one another.

The applicator roller may be the roller configured to directly contact the surface of the aerosol-generating substrate.

As used thereafter, the expression “the at least one roller” refers to “at least one roller among the one or more: applicator roller, intermediate roller, metering roller and backing roller”. The number of respective applicator roller, intermediate roller, metering roller and backing roller is not limited and may be adapted according to the configuration of the system.

The additive may be dispensed by the action of gravity from the reservoir to the roller amongst the at least one roller that is the closest from the dispensing opening of the reservoir. In an embodiment wherein the system comprises one roller only, the additive may be dispensed by the action of gravity directly onto the external surface of the applicator roller. In a variant wherein the system comprises further rollers in addition to the applicator roller, the additive may be dispensed by the action of gravity onto the external surface of the roller that is positioned the closest from the dispensing opening of the reservoir. Then, the additive may be successively dispensed from roller to roller until the applicator roller.

The rotational axis of the at least one roller may be perpendicular to the conveying direction. The respective rotational axis of the rollers may be parallel to one another.

The applicator roller may be configured to rotate around its respective rotational axis in a first direction. The applicator roller may be configured to rotate around its respective rotational axis in a second direction, the second direction being opposite to the first direction.

When the system comprises one applicator roller and at least one further rollers amongst an applicator roller, intermediate roller, metering roller and backing roller, the at least two rollers may rotate in a same direction. Alternatively, when the system comprises one applicator roller and at least one further rollers amongst an applicator roller, intermediate roller, metering roller, and backing roller, the at least two rollers may rotate in opposite direction. In a first embodiment, the system may comprise one applicator roller rotating in a clockwise direction and one backing roller rotating in a counterclockwise direction. In the first embodiment, the external surface of the applicator roller may be adjusted to be spaced apart from the surface of the aerosol-generating substrate by a distance corresponding to the thickness of additive dispensed on the external surface of the applicator roller. In a second embodiment, the system may comprise one applicator roller rotating in a counterclockwise direction and one backing roller rotating in a counterclockwise direction. In the second embodiment, the distance between the external surface of the applicator roller and the surface of the aerosol-generating substrate may be reduced in comparison to the first embodiment. In another embodiment, the system may comprise one applicator roller rotating in a clockwise direction, one metering roller rotating in a counterclockwise direction and one backing roller rotating in a counterclockwise direction. In another embodiment, the system may comprise one applicator roller rotating in a clockwise direction, one metering roller rotating in a clockwise direction and one backing roller rotating in a counterclockwise direction. Alternatively, in one embodiment, the system may comprise one applicator roller rotating in a counterclockwise direction, one metering roller rotating in a counterclockwise direction and one backing roller rotating in a clockwise direction. As used therein “clockwise direction” is defined in relation to the conveying direction. In other word, when a roller rotates in the clockwise direction, the roller rotates towards the conveying direction of the aerosol-generating substrate. As used therein “counterclockwise direction” is a rotating direction opposite to the clockwise direction.

The system may be configured to adjust the rotational speed of each roller. The adjustment of the roller speed may help for adjusting the thickness of the additive deposited on the at least one roller. The adjustment of the roller speed may help for adjusting the thickness of the additive deposited on the aerosol-generating substrate. Adapting the relative rotational speed of the applicator roller with respect to a conveying speed of the aerosol-generating substrate may allow controlling better the quantity of additive deposited on the aerosol-generating substrate. It is understood that higher is the rotational speed of the applicator roller with respect to the conveying speed of the aerosol-generating substrate, greater can be the amount of additive deposited on the aerosol-generating substrate. In embodiments where the system comprises an applicator roller and at least one of a metering roller or an intermediate roller, using different relative rotational speeds for the at least two rollers may allow adjusting the thickness of the additive with a greater accuracy than in embodiments where the relative rotational speeds would be the same.

Moreover, due to the rotation of the rollers, in particular the continuous rotation of the rollers, the presence of crystallized aggregates of additive on the rollers can be prevented so that it does not interfere with the deposition and the thickness of the additive. The crystallized aggregates of additive may be crushed between two rollers up to an aggregate's size that would be small enough for not interfering with the deposition of additive.

At least one of the rollers above-mentioned may be made of metal, in particular of steel. At least one of the rollers above-mentioned may be coated with rubber. Because the coefficient of thermal expansion of rubber is less than the coefficient of thermal expansion of metal, it may be preferable to heat the rubber coating rather than the metallic roller itself for preventing unwanted expansion. Heating may, for instance, help the additive to remain in a temperature range above its melting temperature. The system may comprise a plurality of metal rollers, some of which are covered by a rubber layer. In particular, alternating metal rollers and rubber coated rollers between the reservoir and the aerosol-generating substrate helps reducing wear of the rollers.

The system may further comprise an adjustment device. The adjustment device may be configured for adjusting the relative position of at least one roller with respect to the dispensing opening of the reservoir and the aerosol-generating substrate. By adjusting two successive rollers closer from one to another, a thinner layer of additive is obtained.

The system may further comprise an optical sensing device to detect the presence of additive on the aerosol-generating substrate. Alternatively or in addition, the optical sensing device may be configured to detect the absence of additive on the aerosol-generating substrate. The optical sensing device may comprise an optical sensor. The optical sensing device may be positioned after the applicator roller with respect to the conveying direction.

The dispensing opening of the reservoir may be calibrated to deposit a determined thickness of additive on the external surface of the applicator roller or, when the system comprises a plurality of rollers, on the external surface of the closest roller to the dispensing opening. The dispensing opening of the reservoir may have a width. The width may extend in the direction parallel to the rotational axis of the applicator roller. The dispensing opening of the reservoir may have a length. The length may extend in a direction parallel to the conveying direction or in the circumferential direction of the roller. The length may be smaller than the width of the dispensing opening. The dispensing opening may comprise a first edge and a second edge. The first edge and the second edge may respectively extend along the width of the dispensing opening. The first edge and the second edge may be distanced from one to another by at most the length of the dispensing opening. The first edge may be positioned before the second edge with respect to a rotational direction of the roller, namely the applicator roller when the system comprises only one roller or the closest roller with respect to the dispensing opening when the system comprises a plurality of rollers. The first edge may be positioned closer than the second edge to the roller, namely the applicator roller when the system comprises only one roller or the closest roller with respect to the dispensing opening when the system comprises a plurality of rollers. The width of the dispensing opening of the reservoir may extend in a direction parallel to the rotational axis of the applicator roller. The first edge may extend in a non-parallel direction with respect to the second edge. The first edge may be positioned at a distance of at most 0.010 millimeters from a surface of applicator roller or the closest roller with respect to the dispensing opening. The second edge may be positioned at a distance of at least 0.020 millimeters from a surface of the applicator roller or the closest roller with respect to the dispensing opening. It allows reaching a micro-millimeter precision of the thickness of the additive dispensed on the surface of the applicator roller, thereby improving the control and the accuracy of the deposition of the additive on the aerosol-generating substrate. The width of the dispensing opening may be shorter than a width of the aerosol-generating substrate, in particular 20% shorter. The width of the dispensing opening of the reservoir defines the width of the additive applied on the aerosol-generating substrate. The width of the additive applied on the aerosol-generating substrate can thus be more accurately controlled than by spraying application because it is independent from the number of droplet per unit of volume and the droplet size distribution. The middle of the width of the dispensing opening of the reservoir may be centered with the longitudinal central axis of the aerosol-generating substrate. When the width of the dispensing opening of the reservoir is shorter than the width of the aerosol-generating substrate, it allows creating margins of same width free of additive on each side of the band of additive applied on the aerosol-generating substrate. The distribution of additive on the aerosol-generating substrate can thus be better controlled, in particular with more accuracy.

The reservoir may comprise a first inlet for feeding the reservoir with the additive. The reservoir may comprise a second inlet for feeding the reservoir with an inert gas. The presence of inert gas allows preventing oxidation of the additive as well as other chemical reactions triggered by the presence of air and that could alter the additive formulation. The inert gas may be argon or nitrogen. The pressure in the reservoir may be adapted to contain the additive at the air ambient pressure surrounding the system. The air ambient pressure may be at about 1013,25 hectopascal (hPa).

The reservoir may have a prism-shape design. The reservoir may have the shape of a truncated prism. The reservoir may have a rectangular prism-shape design. The reservoir may have a triangular prism-shape design. The reservoir may have a triangular prism-shape design. The reservoir may comprise a first side and a second side, where the first side is geometrically opposite to the second side. The first side may be connected to the second side by one or more lateral walls. The reservoir may be integrally formed. The first side of the reservoir may have a surface greater than the second side of the reservoir. The first side may be a rectangular surface. The second side of the reservoir may be provided with the dispensing opening.

The reservoir may comprise at least two dispensing openings respectively configured for dispensing an additive. The at least two dispensing openings may have identical dimensions and shapes. Alternatively, the at least two dispensing openings may have respectively different size or shape from one to another. The system may comprise at least two reservoirs. A first reservoir may contain a first additive. A second reservoir may contain a second additive. The first additive and the second additive may be the same additive. Alternatively, the first additive may be different from the second additive. In relation to the arrangement of the first reservoir and the second reservoir with respect to the at least one applicator roller and the aerosol-generating substrate, it allows depositing a pattern of two bands of additive on the aerosol-generating substrate with an improved accuracy, in particular in comparison with the spraying application.

The reservoir may be configured to contain and dispense additive in a liquid state in the reservoir. The system may comprise at least one heating device. This may improve the processing of the additive. This may reduce the viscosity of the additive. The at least one heating device may be configured to heat an external wall of the reservoir. Alternatively or in addition, the at least one heating device may be configured to heat an inner wall of the reservoir. As used therein, the external wall of the reservoir is exposed to the external environment. As used therein, the inner wall of the reservoir is adapted to be in surface contact with the additive contained in the reservoir. The at least one heating device may be an infrared heating lamp. The reservoir may be provided with a temperature sensor for sensing the temperature of an inner volume of the reservoir, of an external wall of the reservoir or an inner wall of the reservoir. Alternatively or in combination, the reservoir may be provided with a temperature sensor for sensing the temperature of the additive contained in the reservoir. A temperature of the reservoir may be comprised between 10 degrees Celsius and 50 degrees Celsius, in particular between 15 degrees Celsius and 35 degrees Celsius, more in particular between 22 degrees Celsius and 28 degrees Celsius. A temperature of the additive in the reservoir may be comprised between 10 degrees Celsius and 50 degrees Celsius, in particular between 15 degrees Celsius and 35 degrees Celsius, more in particular between 22 degrees Celsius and 28 degrees Celsius. This may improve processability of the additive. An additive which has a crystalline aggregate state at around 20 degrees Celsius that is at ambient room temperature, may change to liquid aggregate state at higher temperatures. This may facilitate processing flavors. This may facilitate processing additives such as menthol, which has a crystal aggregate state at ambient room temperature.

The reservoir may be provided with a temperature controlling device. The temperature controlling device may be configured to monitor and control the temperature of the additive in the reservoir. The temperature controlling device may advantageously allow keeping the additive in a predetermined temperature or a predetermined range of temperatures, in particular above a predetermined temperature threshold. The system may comprise at least one heating device configured for generating heat to the additive contained in the reservoir. The temperature controlling device may be configured with a minimum threshold temperature for maintaining the additive in a liquid state in the reservoir. For instance, the temperature controlling device helps an additive containing menthol to remain in a liquid state in the reservoir and above the melting temperature of the menthol, thereby preventing crystallization of the menthol. The temperature controlling device may help to assure the stability and consistency of the fluid characteristics, like the viscosity, of the additive.

The system may comprise at least one heating device configured for generating heat to the additive dispensed on at least one of the roller. The at least one heating device can allow keeping the additive in a liquid state at a particular viscosity coefficient on the external surface of the at least one roller. The at least one of the roller may be provided with a temperature sensor. The at least one heating device may be configured such that at least one of the roller, in particular the applicator roller, has a temperature comprised between 0 degrees Celsius and 70 degrees Celsius, in particular between 5 degrees Celsius and 60 degrees Celsius, more in particular between 25 degrees Celsius and 50 degrees Celsius. This may improve processability of the additive. An additive which has a crystalline aggregate state at around 20 degrees Celsius that is at ambient room temperature, may change to liquid aggregate state at higher temperatures. This may facilitate processing flavors. This may facilitate processing additives such as menthol, which has a crystal aggregate state at ambient room temperature. The at least one heating device may be internal to the respective roller. The at least one heating device may comprise an inner heated water circuit. Alternatively, or in addition, the at least one heating device may be based on electric resistive heating. At least one of the rollers may be a heating roller temperature controlled. A heating roller temperature controlled may help reducing any quality problems that could be caused by roller heat disturbance.

The system may comprise at least one cooling device. The at least one cooling device may be configured to lower the temperature of the additive in the reservoir. The at least one cooling device may be configured to lower the temperature of the external surface of at least one of the rollers. At least one of the roller may be cooled by means of water flowing inside the roller.

The system may comprise at least one doctor blade. The doctor blade may comprise a metallic blade, in particular a steel blade. The doctor blade may comprise a polymer blade. The blade of the doctor blade may have a straight sharp edge. The blade of the doctor blade may have a beveled edge. The at least one doctor blade may be configured for adjusting the thickness of the additive disposed on the roller being arranged at the dispensing opening of the reservoir. The at least one doctor blade may be positioned behind the dispensing opening of the reservoir with respect to a rotational direction of the roller. The doctor blade may be configured for removing remaining additive from the applicator roller. The doctor blade allows providing the roller with a clean external surface portion, i.e. a portion of the roller substantially free of additive, so that the additive may be dispensed from the reservoir onto a clean surface of the roller. It allows reducing thickness disturbance of the additive. The thickness of the additive can thus be controlled more accurately.

According to a second aspect of the present invention, there is provided an aerosol-generating article comprising an aerosol-generating substrate, in particular according to one of the preceding embodiments, wherein the aerosol-generating substrate comprises a band of additive. The band of additive is provided on the aerosol-generating substrate. The band of additive has a width shorter than a width of the aerosol-generating substrate.

According to another aspect of the present invention, there is provided an aerosol-generating article comprising an aerosol-generating substrate, in particular according to one of the preceding embodiments, wherein the aerosol-generating substrate may comprise a band of additive. The band of additive may be provided on the aerosol-generating substrate. The band of additive may have a width shorter than a width of the aerosol-generating substrate.

The band of additive may have a thickness. The thickness may be the height of the additive on the aerosol-generating substrate or the penetration depth of the additive in the aerosol-generating substrate or the sum of both. A variation of the thickness of the band of additive along the width of the band of additive may be less than 50%, in particular less than 30%, more in particular less than 20%. The band of additive may have a thickness of at least 20 micrometers. Hence, an aerosol-generating article with a precise and accurate amount of additive on the aerosol-generating substrate is advantageously obtained. A better reproducibility of the aerosol-generating article may contribute to enhance the user experience.

According to a third aspect of the present invention, there is provided a method for applying an additive to an aerosol-generating substrate for an aerosol-generating article. The method comprises: dispensing an additive from a reservoir to a roller through a dispensing opening of the reservoir; moving the aerosol-generating substrate along a conveying direction, rotating the roller for applying the additive to the aerosol-generating substrate.

According to another aspect of the present invention, there is provided a method for applying an additive to an aerosol-generating substrate for an aerosol-generating article. The method may comprise dispensing an additive from a reservoir to a roller through a dispensing opening of the reservoir. The method may comprise moving the aerosol-generating substrate along a conveying direction. The method may comprise rotating the roller for applying the additive to the aerosol-generating substrate.

This may enable to deposit additive into the aerosol-generating substrate at a well-defined position.

According to a fourth aspect of the present invention, there is provided a use of an applicator roller for applying an additive on an aerosol-generating substrate for an aerosol-generating article, the additive comprising a flavoring component.

The invention is defined in the claims. However, below there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

Example Ex1: System for applying an additive to an aerosol-generating substrate for an aerosol-generating article, comprising: an aerosol-generating substrate; a reservoir, the reservoir containing an additive; an applicator roller adapted to rotate around a rotational axis, wherein the reservoir comprises a dispensing opening to dispense the additive to the applicator roller; wherein the applicator roller is configured to transfer the additive from the applicator roller to the aerosol-generating substrate by a rotational movement of the applicator roller around its rotational axis and a relative movement of the aerosol-generating substrate with respect to the applicator roller in a conveying direction.

Example Ex2: System according to Ex1, further comprising a conveyor device configured to convey an aerosol-generating substrate in the conveying direction with respect to the applicator roller.

Example Ex3: System according to Ex1 or Ex2, wherein the rotational axis of the at least one roller is perpendicular to the conveying direction.

Example Ex4: System according to any Ex1 to Ex3, wherein the aerosol-generating substrate is made of a crimped aerosol-generating material.

Example Ex5: System according to any Ex1 to Ex4, wherein the aerosol-generating substrate has a thickness comprised between 0.110 and 0.380 millimeters, in particular between 0.170 and 0.270 millimeters.

Example Ex6: System according to any Ex1 to Ex5, wherein the aerosol-generating substrate is an herbaceous or plant-based cast sheet.

Example Ex7: System according to any Ex1 to Ex6, wherein the aerosol-generating substrate contains an alkaloid, in particular nicotine.

Example Ex8: System according to any Ex1 to Ex6, wherein the aerosol-generating substrate is tobacco-free.

Example Ex9: System according to any Ex1 to Ex8, wherein the aerosol-generating substrate is a fiber-based material.

Example Ex10: System according to Ex9, wherein the aerosol-generating substrate is a plastic fiber-based material, more preferably a biodegradable fiber-based material, more preferably cotton, more preferably cellulose.

Example Ex11: System according to any Ex1 to Ex10, wherein the additive is at least partially absorbed into the aerosol-generating substrate.

Example Ex12: System according to any Ex1 to Ex7 or Ex9 to Ex11, wherein the aerosol-generating substrate is a homogenized tobacco sheet.

Example Ex13: System according to any Ex1 to Ex12, wherein the additive comprises at least one flavoring component.

Example Ex14: System according to Ex13, wherein the additive comprises essential oil.

Example Ex15: System according to Ex13 or Ex14, wherein the flavoring component comprises natural or synthetic menthol.

Example Ex16: System according to any Ex1 to Ex15, further comprising at least one intermediate roller arranged between the reservoir and the applicator roller, the at least one intermediate roller is configured for transferring the additive dispensed from the dispensing opening of the reservoir to the applicator roller.

Example Ex17: System according to Ex16, wherein the at least one intermediate roller is a metering roller.

Example Ex18: System according to any Ex1 to Ex17, further comprising at least two applicator rollers with a respective rotational axis, and the rotational axis of the at least two applicator rollers are coincident with one another.

Example Ex19: System according to any Ex1 to Ex18, further comprising at least one backing roller, and the at least one backing roller and the applicator roller are arranged to apply pressure from both sides to the aerosol-generating substrate.

Example Ex20: System according to any Ex1 to Ex19, wherein at least one or all of the applicator roller, intermediate roller, metering roller, and backing roller of the system is made of metal, in particular steel.

Example Ex21: System according to any Ex1 to Ex20, wherein at least one or all of the applicator roller, intermediate roller, metering roller, and backing roller of the system is coated with rubber.

Example Ex22: System according to any Ex1 to Ex21, further comprising an adjustment device, and the adjustment device is configured for adjusting the relative position of at least one of the applicator roller, intermediate roller, metering roller and backing roller, with respect to the dispensing opening of the reservoir and the aerosol-generating substrate.

Example Ex23: System according to any Ex1 to Ex22, further comprising an optical sensing device to detect the presence of additive on the aerosol-generating substrate.

Example Ex24: System according to Ex23, wherein the optical sensing device is positioned after the applicator roller with respect to a conveying direction.

Example Ex25: System according to any Ex1 to Ex24, wherein the dispensing opening of the reservoir has a width, and wherein the dispensing opening of the reservoir has a length being smaller than the width of the dispensing opening, and the dispensing opening comprises a first edge and a second edge, the first edge and the second edge are distanced from one to another by at most the length of the dispensing opening; wherein the first edge is positioned before the second edge with respect to a rotational direction of the roller, and the first edge is positioned closer to the roller than the second edge.

Example Ex26: System according to Ex25, wherein the width of the dispensing opening of the reservoir extends in a direction parallel to the rotational axis of the applicator roller.

Example Ex27: System according to Ex25 or Ex26, wherein the first edge is positioned at a distance of at most 0.010 millimeters from a surface of the roller.

Example Ex28: System according to any Ex25 to Ex27, wherein the second edge is positioned at a distance of at least 0.020 millimeters from a surface of the roller.

Example Ex29: System according to any Ex25 to Ex28, wherein the width of the dispensing opening is shorter than a width of the aerosol-generating substrate, in particular 20% shorter.

Example Ex30: System according to any Ex25 to Ex29, wherein the width of the dispensing opening of the reservoir is arranged perpendicularly to a longitudinal central axis of the aerosol-generating substrate, and the middle of the width of the dispensing opening of the reservoir is centered with the longitudinal central axis of the aerosol-generating substrate.

Example Ex31: System according to any Ex1 to Ex30, wherein the reservoir comprises a first inlet for feeding the reservoir with the additive, and a second inlet for feeding the reservoir with an inert gas.

Example Ex32: System according to Ex31, wherein the inert gas is argon or nitrogen.

Example Ex33: System according to any Ex1 to Ex32, wherein the pressure in the reservoir is adapted to contain the additive at the air ambient pressure surrounding the system.

Example Ex34: System according to any Ex1 to Ex33, wherein the additive is dispensed by the action of gravity from the reservoir to the applicator.

Example Ex35: System according to any Ex1 to Ex34, wherein the reservoir comprises at least two dispensing openings respectively configured for dispensing an additive.

Example Ex36: System according to Ex35, wherein the at least two dispensing openings have identical dimensions.

Example Ex37: System according to Ex35, wherein the at least two dispensing openings have respectively different size from one to another.

Example Ex38: System according to any Ex1 to Ex37, comprising at least two reservoirs, the first reservoir containing a first additive, the second reservoir containing a second additive.

Example Ex39: System according to Ex38, wherein the first additive and the second additive are the same additive.

Example Ex40: System according to Ex38, wherein the first additive is different from the second additive.

Example Ex41: System according to any Ex1 to Ex40, wherein the reservoir is provided with a temperature controlling device, the temperature controlling device is configured to monitor and control the temperature of the additive in the reservoir.

Example Ex42: System according to any Ex1 to Ex41, wherein the reservoir is configured to contain and dispense additive in a liquid state in the reservoir.

Example Ex43: System according to any Ex1 to Ex42, comprising at least one heating device configured for generating heat to the additive contained in the reservoir.

Example Ex44: System according to Ex41, wherein the temperature controlling device is configured with a minimum threshold temperature for maintaining the additive in a liquid state in the reservoir.

Example Ex45: System according to any Ex1 to Ex44, comprising at least one heating device configured for generating heat to the additive dispensed on at least one of the roller.

Example Ex46: System according to any Ex1 to Ex45, wherein the applicator roller or at least one of the intermediate rollers is a heating roller temperature controlled.

Example Ex47: System according to any Ex1 to Ex46, comprising at least one doctor blade, the at least one doctor blade is configured for adjusting the thickness of the additive disposed on the roller being arranged at the dispensing opening of the reservoir.

Example Ex48: System according to any Ex1 to Ex47, comprising at least one doctor blade, the at least one doctor blade is positioned behind the dispensing opening of the reservoir with respect to a rotational direction of the roller, and the doctor blade is configured for removing remaining additive from the applicator roller.

Example Ex49: An aerosol-generating article comprising an aerosol-generating substrate, in particular according to one of the preceding claims, wherein the aerosol-generating substrate comprises a band of additive, the band of additive is provided on the aerosol-generating substrate, and the band of additive has a width shorter than a width of the aerosol-generating substrate.

Example Ex50: The aerosol-generating article according to Ex49, wherein the band of additive has a thickness, and a variation of the thickness of the band of additive along the width of the band of additive is less than 50%, in particular less than 30%.

Example Ex51: The aerosol-generating article according to Ex49 or Ex50, wherein the band of additive has a thickness of at least 20 micrometers.

Example Ex52: A method for applying an additive to an aerosol-generating substrate for an aerosol-generating article, comprising: dispensing an additive from a reservoir to a roller through a dispensing opening of the reservoir; moving the aerosol-generating substrate along a conveying direction, rotating the roller for applying the additive to the aerosol-generating substrate.

Example Ex53: Use of an applicator roller for applying an additive on an aerosol-generating substrate for an aerosol-generating article, the additive comprising a flavoring component.

Examples will now be further described with reference to the figures.

FIG. 1 shows a schematic representation of a system for producing an aerosol-generating substrate comprising one roller.

FIG. 2 shows the system of FIG. 1 where the conveying direction is curved in comparison to FIG. 1.

FIG. 3 shows a schematic representation of a system for producing an aerosol-generating substrate comprising two rollers.

FIG. 4 shows a schematic top view of the aerosol-generating substrate after application of the additive.

FIG. 5 shows a schematic representation of a system for producing an aerosol-generating substrate comprising a reservoir with two dispensing openings.

FIG. 6 shows a schematic representation of a system for producing an aerosol-generating substrate comprising two reservoirs as illustrated in FIG. 5.

FIG. 1 shows a system 1 for applying an additive to an aerosol-generating substrate 3, which is conveyed by a conveyor device 5 in a conveying direction 101. The system 1 comprises an applicator roller 11. The applicator roller 11 is adapted to rotate around a rotational axis 103. The rotational axis 103 is arranged transversally with respect to the conveying direction 101. In the embodiment illustrated by FIG. 1, the applicator roller 11 rotates clockwise (see arrow) around the rotational axis 103, such that its circumference tangentially moves in the conveying direction 101. In a variant, the applicator roller 11 could rotate in an opposite direction. The applicator roller 11 may be made of metal, in particular of steel. The aerosol-generating substrate 3 is conveyed and pressed between the applicator roller 11 and a backing roller 13. The backing roller 13 rotates around a rotational axis 105 (see arrow). The rotational axis 105 is parallel to the rotational axis 103. The backing roller 13 rotates in an opposite direction with respect to the rotation of the applicator roller 11. The backing roller 13 may be made of metal, in particular of steel. Optionally, the backing roller 13 may be covered with a layer of rubber 15. the backing roller 13 may be part of the conveying device 5.

The system 1 further comprises a reservoir 17. In the embodiment illustrated by FIG. 1, the reservoir 17 has a shape of a truncated prism. The reservoir 17 is provided with a rectangular base 19. The rectangular base 19 is geometrically opposite to a dispensing opening 21 of the reservoir 17. The dispensing opening 21 is defined by a width (perpendicular to the cut-view of FIG. 1, but represented in the top view of FIG. 4) in a direction parallel to the rotational axis 103 of the applicator roller 11 and a length 23 in a direction parallel to the conveying direction 100. In the embodiment illustrated by FIG. 1, the length 23 of the dispensing opening 21 is smaller than the width of the dispensing opening 21. The dispensing opening 21 comprises a first edge 25 and a second edge 27. The first edge 25 and the second edge 27 respectively extend along the width of the dispensing opening 21 and are distanced from one to another by the length 23 of the dispensing opening 21. The first edge 25 is positioned before the second edge 27 with respect to a rotational direction (see arrow) of the applicator roller 11 around the rotational axis 103. The first edge 25 is positioned closer to an external surface 29 of the applicator roller 11 than the second edge 27. The distance 31 between the first edge 25 and the external surface 29 of the applicator roller 11 allows accurately defining the thickness an additive 33 dispensed from the reservoir 17, in particular up to a micro-millimeter precision of the thickness. The additive 33 is dispensed to the applicator roller 11 by the action of gravity through the dispensing opening 21. The additive 33 is in a liquid state in the reservoir 17. To keep the additive 33 in a liquid state in the reservoir 17, and thus with an appropriate viscosity, the reservoir 17 may be provided with a heating device 35. The heating device 35 may be arranged on an inner or an outer wall of the reservoir 17. In the embodiment illustrated by FIG. 1, a heating device 35 is provided on an outer side of respective lateral walls 37, 39 of the reservoir 17. The lateral wall 37 extends from the first edge 25 to the base 19. The lateral wall 39 extends from the second edge 27 to the base 19.

The additive 33 may comprise at least one flavoring component. The at least one flavoring component may be menthol. To prevent and avoid an unwanted chemical reaction of the additive 33 in the reservoir 17, in particular oxidation caused by exposition to the ambient air, the reservoir contains an inert gas 41. The inert gas 41 is fed to the reservoir 17 via a pipe 43 and a corresponding valve 45. Similarly, the additive 33 is fed to the reservoir 17 via a pipe 47 and a corresponding valve 49.

In the system 1 according to the embodiment illustrated by FIG. 1, the system 1 further comprises doctor blades 51, 53. The first doctor blade 51 is positioned between the dispensing opening 21 and the aerosol-generating substrate 3, when the aerosol-generating substrate 3 is positioned after the dispensing opening 21 according to the rotational direction (see arrow) of the applicator roller 11 around the rotational axis 103. The first doctor blade 51 is thus positioned with respect to the applicator roller 11 before deposition of the additive 33 onto the aerosol-generating substrate 3. The first doctor blade 51 allows further improving the establishment of the desired thickness of the additive 33 by adjusting the position of the first doctor blade 51 with respect to the external surface 29 of the applicator roller 11. For instance, the first doctor blade 51 may be positioned in order to remove an extra quantity of additive 33 with respect to the desired thickness of additive 33. The second doctor blade 53 is positioned between the dispensing opening 21 and the aerosol-generating substrate 3, when the aerosol-generating substrate 3 is positioned before the dispensing opening 21 according to the rotational direction (see arrow) of the applicator roller 11 around the rotational axis 103. The second doctor blade 53 is thus positioned with respect to the applicator roller 11 after deposition of the additive 33 onto the aerosol-generating substrate 3. The second doctor blade 53 is configured for removing remaining additive 33 from the external surface 29 of the applicator roller 11.

Once the additive 33 has been deposited on the aerosol-generating substrate 3 by means of the applicator roller 11, the aerosol-generating substrate 3 is conveyed along a downstream direction 107 towards a funnel-shape device 55. The funnel-shape device 55 is configured to fold the aerosol-generating substrate 3 into a segment, in particular in a rod shape, for producing an aerosol-generating article (not represented).

In the embodiment illustrated by FIG. 1, the conveying direction 101 is parallel and aligned with the downstream direction 107. FIG. 2 shows a variant of the system 1 of FIG. 1 where the conveying direction 109 is inclined with respect to the downstream direction 107. The system of FIG. 2 is similar to the system of FIG. 1 and like reference numerals have been used to identify like elements. In the embodiment illustrated by FIG. 2, the conveying direction 109 is inclined with respect to the downstream direction 107 by an inclination angle 111. The inclination angle 111 is about 45 degrees in the schematic view of FIG. 2. The inclination angle 111 may be defined in relation to the convexity of the external surface 29 of the applicator roller 11. As shown by the dotted circle 57 in FIG. 2, in this embodiment a length of the aerosol-generating substrate 3 upstream the applicator roller 11 is bent with respect to the downstream direction 107. In this inclined configuration, a greater length of the aerosol-generating substrate 3 may be brought into contact with the applicator roller 11 than in a configuration wherein the conveying direction 101 is parallel to the downstream direction 107, as shown by the dotted circle 57 in FIG. 2. The configuration of FIG. 2 helps stabilizing the quantity of additive 33 deposited on the aerosol-generating substrate 3 and increasing the deposition consistency. It also increases the quantity of additive 33 deposited on the aerosol-generating substrate 3.

FIG. 3 shows a schematic representation of a system 2 for producing an aerosol-generating substrate 3 comprising two rollers 11, 12. The elements of the system 2 similar to the elements of the system 1 and previously described with respect to FIG. 1 are identified by the same odd reference numerals. The elements of system 2 differing from the elements of system 1 are indicated by even reference numerals. In the embodiment represented by FIG .3, the system 2 comprises the applicator roller 11 and an intermediate roller 12. The applicator roller 11 is configured so as to be in contact with the aerosol-generating substrate 3 to apply the additive. The intermediate roller 12 is arranged in an intermediate position in between the dispensing opening 21 of the reservoir 17 and the applicator roller 11. In particular, the intermediate roller 12 may be a metering roller 12. In a variant not illustrated, the system 2 may comprise more than one intermediate roller 12. The intermediate roller 12 is adapted to rotate around a rotational axis 102. The rotational axis 102 is parallel to the rotational axis 103. In the embodiment illustrated by FIG. 3, the applicator roller 11 rotates clockwise (see arrow) around the rotational axis 103 in relation to the conveying direction 101, while the intermediate roller 12 rotates in an opposite direction, i.e. counterclockwise (see arrow), around the rotational axis 102. The intermediate roller 12 may be coated with a rubber layer (not shown). The rubber layer of the intermediate roller 12 may be heated, in particular to keep the additive 33 in a liquid state. The intermediate roller 12 helps further adjusting the quantity of additive deposited on the aerosol-generating substrate 3. Indeed, an adjustment of the distance 14 between the applicator roller 11 and the intermediate roller 12 allows better defining the thickness of the additive 33 than in a system comprising one single roller 11.

FIG. 4 shows a schematic top view of the aerosol-generating substrate 3 after application of the additive 33 obtained by means of the system 1 or 2. The aerosol-generating substrate 3 comprises a band 59 of additive 33. The band 59 of additive 33 is provided on the aerosol-generating substrate 3. The band 59 of additive 33 may be partially absorbed by the aerosol-generating substrate 3, in particular depending on the porosity of the aerosol-generating substrate 3. The band 59 of additive 33 has a width 61 shorter than a width 63 of the aerosol-generating substrate 3. The width 61 of the additive 33 applied on the aerosol-generating substrate 3 may be more accurately controlled than by spraying application because it is independent from the number of droplet per unit of volume and the droplet size distribution. The width 61 of the band 59 of additive 33 is defined by the width 65 of the dispensing opening 21 of the reservoir 17. The width 65 of the dispensing opening 21 extends respectively along the first edge 25 and the second edge 27 of the dispensing opening 21. As mentioned with respect to FIG. 1, the first edge 25 and the second edge 27 are distanced from one to another by the length 23 of the dispensing opening 21. In the embodiment represented by FIG. 4, the width 65 of the dispensing opening 21 is shorter than the width 63 of the aerosol-generating substrate 3. Moreover, in the embodiment represented by FIG. 4, the middle of the width 65 of the dispensing opening 21 of the reservoir 17 is centered with the longitudinal central axis 113 of the aerosol-generating substrate 3. Because the width 65 of the dispensing opening 21 of the reservoir 17 is shorter than the width 63 of the aerosol-generating substrate 3, it allows creating margins 67 of same width free of additive on each side of the band 59 of additive 33. The system 1, 2 according to the present invention thus allows producing an aerosol-generating substrate 3 with a distribution of additive 33 that can be better defined and controlled and, in particular with respect to the known additive spraying method.

FIG. 5 shows a schematic representation of the system 1 with a reservoir 170. The reservoir 170 differs from the reservoir 17 previously described in reference to FIG. 1 in that the reservoir 170 comprises two dispensing openings 21, 210, instead of only one dispensing opening 21. The dispensing opening 210 is not visible in the cut view of FIG. 5 but is indicated by a dotted arrow for sake of clarity. The dispensing opening 21, 210 are spaced from one to another by a distance 69. As a result, the respective bands 59, 590 of additive 33 on the aerosol-generating substrate 3 are spaced from one to another by the same distance 69. Hence, by adapting the number of dispensing openings and the dimensions of the dispensing openings, a specific pattern of band of additive may be advantageously achieved.

FIG. 6 shows a schematic representation of the system 1 with two reservoirs 170, as described in reference to FIG. 5. A first reservoir 170 contains a first additive 33. The first additive 33 is fed to the first reservoir 170 by means of the pipe 47, as explained with respect to FIG. 1. A second reservoir 170 contains a second additive 330. The second additive 330 is fed to the first reservoir 170 by means of the pipe 47, as explained with respect to FIG. 1. The first additive 33 may be different from the second additive 330. As a result, an aerosol-generating substrate 3 comprising four bands 59, 590 of additive 33, 330 is obtained, in particular two bands 59, 590 of the first additive 33 and two bands of the second additive 330.

For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term “about”. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ±10% of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

Claims

1-15. (canceled)

16. A system for applying an additive to an aerosol-generating substrate for an aerosol-generating article, the system comprising:

an aerosol-generating substrate, the aerosol-generating substrate being a sheet, a foil, or a web of aerosol-generating material;

a reservoir containing an additive;

an applicator roller configured to rotate around a rotational axis,

wherein the reservoir comprises a dispensing opening configured to dispense the additive to the applicator roller,

wherein the applicator roller is further configured to transfer the additive from the applicator roller to the aerosol-generating substrate by a rotational movement of the applicator roller around a rotational axis thereof and a relative movement of the aerosol-generating substrate with respect to the applicator roller in a conveying direction; and

at least one backing roller, the at least one backing roller and the applicator roller being arranged to apply pressure from both sides to the aerosol-generating substrate.

17. The system according to claim 16, wherein the aerosol-generating substrate is a homogenized tobacco sheet.

18. The system according to claim 16, wherein the additive comprises at least one flavoring component.

19. The system according to claim 16, further comprising at least one intermediate roller arranged between the reservoir and the applicator roller, the at least one intermediate roller being configured to transfer the additive dispensed from the dispensing opening of the reservoir to the applicator roller.

20. The system according to claim 19, wherein the at least one intermediate roller is a metering roller.

21. The system according to claim 16,

wherein the dispensing opening of the reservoir has a width,

wherein the dispensing opening of the reservoir has a length being smaller than the width of the dispensing opening,

wherein the dispensing opening of the reservoir comprises a first edge and a second edge, the first edge and the second edge being distanced from one to another by at most the length of the dispensing opening, and

wherein the first edge is positioned before the second edge with respect to a rotational direction of the roller, and the first edge is positioned closer to the roller than the second edge.

22. The system according to claim 16, wherein the reservoir further comprises a first inlet configured to feed the reservoir with the additive, and a second inlet configured to feed the reservoir with an inert gas.

23. The system according to claim 16, further comprising at least two reservoirs, a first reservoir of the at least two reservoirs containing a first additive, and the second reservoir of the at least two reservoirs containing a second additive.

24. The system according to claim 16, wherein the reservoir is provided with a temperature controlling device configured to monitor and control a temperature of the additive in the reservoir.

25. The system according to claim 16, further comprising at least one doctor blade configured to adjust a thickness of the additive disposed on the applicator roller and being arranged at the dispensing opening of the reservoir.

26. The system according to claim 16, further comprising at least one doctor blade positioned behind the dispensing opening of the reservoir with respect to a rotational direction of the roller and being configured to remove remaining additive from the applicator roller.

27. A method for applying an additive to an aerosol-generating substrate for an aerosol-generating article, where the aerosol-generating substrate is a sheet, a foil, or a web of aerosol-generating material, the method comprising:

dispensing an additive from a reservoir to a roller through a dispensing opening of the reservoir;

moving the aerosol-generating substrate along a conveying direction; and

rotating the roller for applying the additive to the aerosol-generating substrate and applying pressure from both sides to the aerosol-generating substrate by means of the roller and at least one backing roller.

28. An applicator roller configured to apply an additive on an aerosol-generating substrate for an aerosol-generating article and at least one backing roller, the aerosol-generating substrate being a sheet, a foil, or a web of aerosol-generating material and the additive comprising a flavoring component, and the at least one backing roller and the applicator roller being arranged to apply pressure from both sides to the aerosol-generating substrate.