FLAVOR STICK, HEAT-NOT-BURN-TYPE FLAVOR INHALATION PRODUCT, AND METHOD FOR PRODUCING FLAVOR STICK

Abstract

This flavor stick is provided with a flavor rod that is inserted into a heating chamber in a flavor inhalation device and is heated by an internal heater in the flavor inhalation device and a mouthpiece part that is connected to the rear end side of the flavor rod, in which the flavor rod is provided with a plurality of thin rods and a piece of outside wrapping paper that wounds the plurality of thin rods in a bundled state, each of the plurality of thin rods is provided with a piece of inside wrapping paper and a flavor source and an aerosol generation base material both arranged inside the piece of inside wrapping paper.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation of PCT International Application No. PCT/JP2021/038784, filed on Oct. 20, 2021, which is hereby expressly incorporated by reference into the present application.

TECHNICAL FIELD

The present invention relates to a flavor stick, a non-combustion-heating-type flavor inhalation product, and a method for manufacturing the flavor stick.

BACKGROUND ART

Flavor sticks for use with a non-combustion-type flavor inhaler for inhaling flavor derived from a flavor source without combustion are known. An example of a known flavor stick includes a flavor rod and a mouthpiece disposed downstream of the flavor rod. The flavor rod is formed by filling a space inside wrapping paper with a filler including a flavor source, such as a tobacco material, and an aerosol-source material, such as glycerine or propylene glycol (see, for example, PTL 1).

This type of flavor stick is used together with a flavor inhalation device for inhalation. Typically, the flavor rod of the flavor stick is inserted into a heating chamber of the flavor inhalation device, and a heater included in the non-combustion-type flavor inhaler heats the flavor source of the flavor rod without combustion. The non-combustion heating causes the flavor source to release an aerosol containing a flavor component, and a user inhales the aerosol through the mouthpiece disposed downstream of the flavor rod.

An example of a known heating method used in the flavor inhalation device is an internal heating method. In this method, when the flavor rod is inserted into the heating chamber, an internal heater is inserted into the flavor rod from the front end of the flavor rod and heats the flavor source from the inside. Internal heaters having various shapes, such as a rod shape or a blade shape, are used in the internal heating method.

CITATION LIST

Patent Literature

• • PTL 1: Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2015-503335
  • PTL 2: Japanese Unexamined Patent Application Publication No. 7-184625
  • PTL 3: Japanese Patent No. 5220762

SUMMARY OF INVENTION

Technical Problem

However, when the flavor inhalation device based on the internal heating method is used for inhalation from the flavor stick according to the related art, the internal heater comes into direct contact with the flavor source included in the flavor rod. Thus, the flavor source adheres to the internal heater of the flavor inhalation device.

The present invention has been made in light of the above-described circumstances, and its object is to provide a technology for suppressing the adhesion of a flavor source included in a flavor rod of a flavor stick to an internal heater of a flavor inhalation device used for inhalation from the flavor stick by the internal heating method.

Solution to Problem

To achieve the above-described object, a flavor stick according to the present invention includes: a flavor rod configured to be inserted into a heating chamber of a flavor inhalation device and heated by an internal heater of the flavor inhalation device; and a mouthpiece connected to a rear end of the flavor rod. The flavor rod includes a plurality of thin rods and outer wrapping paper with which the plurality of thin rods are bundled and wrapped. Each of the plurality of thin rods includes inner wrapping paper, a flavor source, and an aerosol-source material, the flavor source and the aerosol-source material being disposed inside the inner wrapping paper. The flavor rod has a heater insertion hole in a central region of the flavor rod in cross-section, the heater insertion hole extending in an axial direction and allowing the internal heater to be inserted into the heater insertion hole from a front end of the flavor rod. The heater insertion hole is defined by outer surfaces of the inner wrapping paper of the plurality of thin rods.

The plurality of thin rods may be arranged around the heater insertion hole in cross-section of the flavor rod.

The inner wrapping paper of each of the plurality of thin rods may be bonded to the outer wrapping paper.

Each of the plurality of thin rods may have an elliptical cross-sectional shape with a minor axis extending in a radial direction of the flavor rod.

The mouthpiece may include a leakage-suppressing portion in a front end section thereof, the leakage-suppressing portion being connected to a rear end of the flavor rod and including an aerosol flow path and a blocking portion, the aerosol flow path extending in the axial direction and allowing an aerosol generated in the plurality of thin rods to flow therethrough, the blocking portion blocking a rear end of a gap formed between adjacent ones of the thin rods.

The blocking portion may extend along the thin rods and the gap and serve as a stopper in regions in which the blocking portion faces the thin rods, the stopper restraining the thin rods from being displaced when the internal heater is inserted.

The present invention may be applied to a non-combustion-type flavor inhalation product. A non-combustion-type flavor inhalation product according to the present invention includes the above-described flavor stick and a flavor inhalation device used for inhalation from the flavor stick, the flavor inhalation device including a heating chamber that allows insertion of the flavor rod of the flavor stick and an internal heater inserted into the heater insertion hole when the flavor rod is inserted into the heating chamber.

The present invention may also be applied to a method for manufacturing a flavor rod. A method according to the present invention is a method for manufacturing a flavor stick including a flavor rod having a heater insertion hole in a central region of the flavor rod in cross-section and a mouthpiece connected to a rear end of the flavor rod, the heater insertion hole allowing an internal heater of a flavor inhalation device to be inserted into the heater insertion hole. The method includes: a step of forming the flavor rod by bundling a plurality of thin rods, in each of which a flavor source containing an aerosol-source material is wrapped with inner wrapping paper, and wrapping the plurality of thin rods together with outer wrapping paper, the flavor rod having the heater insertion hole defined by outer surfaces of the inner wrapping paper of the thin rods, the heater insertion hole extending along an axial direction in the central region of the flavor rod in cross-section; and a connecting step in which the flavor rod and the mouthpiece are arranged in series and wrapped together with tipping paper.

The step of forming the flavor rod may include: a long-thin-rod forming step in which a plurality of long thin rods are formed in parallel with each other along a transport direction of a wrapping machine by wrapping the flavor source containing the aerosol-source material with long-sheet-shaped thin-rod wrapping paper continuously in a longitudinal direction; a long-flavor-rod forming step in which the plurality of long thin rods are joined and wrapped together with long outer wrapping paper to form a long flavor rod; and a cutting step in which the long flavor rod is cut to a predetermined length to form the flavor rod.

Alternatively, the step of forming the flavor rod may include: a long-flavor-rod forming step in which a long flavor rod is formed by supplying double-length first components, each of which is twice as long as a first component that constitutes a portion of the mouthpiece, to long-sheet-shaped long outer wrapping paper at regular intervals while the long outer wrapping paper is transported along a transport path of a wrapping machine, supplying a plurality of double-length thin rods, which are twice as long as the thin rods, to rod-receiving spaces formed between the double-length first components to form bundles of the double-length thin rods, and then wrapping together the double-length first components and the bundles of the double-length thin rods arranged in series with the long outer wrapping paper; and a cutting step in which the long flavor rod is cut at centers of the double-length first components in a length direction and centers of the double-length thin rods in the length direction to form intermediate assemblies in each of which the flavor rod is connected to the first component. In the connecting step, one of the intermediate assemblies and one or more second components that constitute another portion of the mouthpiece may be wrapped together with the tipping paper while the one or more second components are arranged in series with the first component of the one of the intermediate assemblies.

The solutions to the problem according to the present invention may be applied in any possible combinations.

Advantageous Effects of Invention

The present invention provides a technology for suppressing the adhesion of a flavor source included in a flavor rod of a flavor stick to an internal heater of a flavor inhalation device used for inhalation from the flavor stick by the internal heating method.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram illustrating a flavor inhalation device for non-combustion heating of a flavor stick according to a first embodiment.

FIG. 2 is a schematic diagram illustrating the internal structure of the flavor stick according to the first embodiment.

FIG. 3 illustrates the structure viewed in the direction of arrow A in FIG. 2.

FIG. 4 is a perspective view of a leakage-suppressing portion according to the first embodiment.

FIG. 5 illustrates the steps for manufacturing a flavor rod according to the first embodiment.

FIG. 6 illustrates a wrapping machine used to manufacture the flavor rod according to the first embodiment.

FIG. 7 illustrates a step for manufacturing the flavor rod according to the first embodiment.

FIG. 8 illustrates another step for manufacturing the flavor rod according to the first embodiment.

FIG. 9 illustrates another step for manufacturing the flavor rod according to the first embodiment.

FIG. 10 illustrates a long-flavor-rod forming step of a second manufacturing method.

FIG. 11 illustrates the shape of a conveyor in cross-section orthogonal to a transport direction.

FIG. 12 illustrates the manner in which a leakage-suppressing-component supply drum and thin-rod supply drums supply respective components at first to fourth positions.

FIG. 13 illustrates the long-flavor-rod forming step of the second manufacturing method.

FIG. 14 illustrates an intermediate assembly formed in a step of forming the flavor rod, and also illustrates a cooling portion, a filter portion, and tipping paper that are separately prepared.

FIG. 15 illustrates a flavor stick manufactured by the second manufacturing method.

FIG. 16 illustrates a leakage-suppressing portion according to a modification.

FIG. 17 is a schematic diagram illustrating the measurement of the hardness of a thin rod.

FIG. 18 illustrates a cross-section of a flavor rod according to a modification of the first embodiment.

FIG. 19 illustrates a step for manufacturing the flavor rod according to the modification of the first embodiment.

FIG. 20 illustrates a cross-section of a flavor rod according to a second modification of the first embodiment.

FIG. 21 illustrates variants of the flavor source included in the thin rod.

DESCRIPTION OF EMBODIMENTS

A flavor stick and a non-combustion-type flavor inhalation product according to an embodiment of the present invention will now be described with reference to the drawings. The dimensions, materials, shapes, relative arrangements, etc., of structural elements described in the embodiment are not intended to limit the technical scope of the present invention only thereto unless specified otherwise.

First Embodiment

FIG. 1 is a schematic diagram illustrating a flavor inhalation device 30 for non-combustion heating of a flavor stick according to a first embodiment. FIG. 2 is a schematic diagram illustrating the internal structure of a flavor stick 1 according to the first embodiment. The flavor inhalation device 30 is an inhalation device used for inhalation from the flavor stick 1. The flavor stick 1 and the flavor inhalation device 30 constitute a non-combustion-type flavor inhalation product.

The flavor inhalation device 30 includes a heating chamber 31 capable of receiving a flavor rod 2 of the flavor stick 1 and having an insertion opening 31A through which the flavor rod 2 can be inserted and extracted. The heating chamber of the flavor inhalation device 30 accommodates an electric internal heater 32 for heating the flavor rod 2.

The flavor stick 1 includes the flavor rod 2 and a mouthpiece 3. The flavor rod 2 is inserted into the heating chamber 31 of the flavor inhalation device 30 and heated by the internal heater 32. The mouthpiece 3 is connected to a rear end of the flavor rod 2. In the present embodiment, for example, the flavor stick 1 has a cylindrical rod shape that extends in one direction. In FIG. 2, reference sign CL denotes a central axis of the flavor stick 1. The flavor rod 2 and the mouthpiece 3 are arranged coaxially, and therefore the central axis CL is also the central axis of the flavor rod 2 and the mouthpiece 3.

The cylindrical-rod-shaped flavor rod 2 and the mouthpiece 3 are arranged coaxially, and are connected together by being coaxially wrapped with tipping paper 8. Reference sign 1a denotes a mouthpiece end 1a formed at the rear end of the flavor stick 1, and 1b denotes the front end of the flavor stick 1. The flavor stick 1 is inserted into the heating chamber 31 of the flavor inhalation device 30 from the front end 1b.

The flavor rod 2 includes plural thin rods 21 and outer wrapping paper 22 with which the thin rods 21 are bundled and wrapped. FIG. 3 illustrates the structure viewed in the direction of arrow A in FIG. 2. FIG. 3 is a front view of the flavor stick 1 (flavor rod 2) viewed from the front-end-1b side. Each of the thin rods 21 that constitute the flavor rod 2 includes inner wrapping paper 23, and also includes a flavor source and an aerosol-source material disposed inside the inner wrapping paper 23. Although the flavor rod 2 includes three thin rods 21 in the example illustrated in FIG. 3, the number of thin rods 21 is not particularly limited as long as two or more thin rods 21 are provided. Each thin rod 21 has a central axis extending parallel to the central axis CL of the flavor stick 1, and extends over the entire length of the flavor rod 2. In FIG. 3, reference sign 24 denotes the flavor source containing the aerosol-source material. Here, an example in which a tobacco filler is used as the flavor source will be described.

When the flavor inhalation device 30 is used for inhalation from the flavor stick 1, the internal heater 32 is activated while the flavor rod 2 of the flavor stick 1 is inserted in the heating chamber. As a result, the flavor source 24 (tobacco filler) containing the aerosol-source material is heated in each thin rod 21, so that an aerosol containing a flavor component (for example, a tobacco component) is released. The aerosol containing the flavor component (for example, the tobacco component) generated in the flavor rod 2 is transmitted to the mouthpiece end 1a through the mouthpiece 3 and inhaled by a user.

The tobacco filler used as the flavor source 24 may contain shredded tobacco. The material of the shredded tobacco contained in the tobacco filler is not particularly limited, and a known material, such as lamina and midrib, may be used. The material may be obtained by crushing dried tobacco leaves into crushed tobacco, uniformizing the crushed tobacco into a sheet (hereinafter also referred to simply as a “uniformized sheet”), and shredding the uniformized sheet. There are plural known methods for manufacturing the uniformized sheet, that is, for crushing tobacco leaves into pieces and forming the pieces into a uniformized sheet. The first method is to produce a sheet by using a papermaking process (sheet-making method). The second is a method of mixing a suitable solvent, such as water, and crushed tobacco leaves into a uniform mixture, casting the uniform mixture on a metal plate or a metal-plate belt, and performing a drying process to produce a cast sheet (slurry method). The third is a method of mixing a suitable solvent, such as water, and crushed tobacco leaves into a uniform mixture and forming the uniform mixture into a sheet shape by extrusion molding to produce a rolled sheet (rolling method).

Alternatively, the tobacco filler may be tobacco strands obtained by cutting the above-described uniformized sheet. The tobacco strands are about as long as the thin rods 21 in the axial direction, and the space inside the inner wrapping paper 23 may be filled with the tobacco strands arranged such that the longitudinal directions thereof coincide with the axial direction of the thin rods 21. It is, of course, not necessary that all the tobacco strands included in each thin rod 21 be arranged to extend in the axial direction of the thin rods 21, and some of the tobacco strands (for example, 50% or more of the total amount of tobacco strands) may be arranged to extend in the axial direction of the thin rods 21. Alternatively, the tobacco filler may be the above-described uniformized sheet folded in a gathered form.

Various types of tobacco may be used to form the tobacco filler. For example, flue-cured tobacco, burley tobacco, orient tobacco, domestic tobacco, other types of Nicotiana tabacum or Nicotiana rustica, or a mixture thereof may be used.

The tobacco filler may contain a flavoring agent. The type of the flavoring agent contained in the tobacco filler is not particularly limited. The flavoring agent may be, for example, acetanisole, acetophenone, acetylpyrazine, 2-acetylthiazole, alfalfa extract, amyl alcohol, amyl butyrate, trans-anethole, star anise oil, apple juice, Peru balsam oil, beeswax absolute, benzaldehyde, benzoin resinoid, benzyl alcohol, benzyl benzoate, benzyl phenylacetate, benzyl propionate, 2,3-butanedione, 2-butanol, butyl butyrate, butyric acid, caramel, cardamom oil, carob absolute, β-carotene, carrot juice, L-carvone, β-caryophyllene, cassia bark oil, cedarwood oil, celery seed oil, chamomile oil, cinnamaldehyde, cinnamic acid, cinnamyl alcohol, cinnamyl cinnamate, citronella oil, DL-citronellol, clary sage extract, cocoa, coffee, cognac oil, coriander oil, cuminaldehyde, davana oil, δ-decalactone, γ-decalactone, decanoic acid, dill herb oil, 3,4-dimethyl-1,2-cyclopentanedione, 4,5-dimethyl-3-hydroxy-2,5-dihydrofuran-2-one, 3,7-dimethyl-6-octenoic acid, 2,3-dimethylpyrazine, 2,5-dimethylpyrazine, 2,6-dimethylpyrazine, ethyl 2-methylbutyrate, ethyl acetate, ethyl butyrate, ethyl hexanoate, ethyl isovalerate, ethyl lactate, ethyl laurate, ethyl levulinate, ethyl maltol, ethyl octanoate, ethyl oleate, ethyl palmitate, ethyl phenylacetate, ethyl propionate, ethyl stearate, ethyl valerate, ethyl vanillin, ethyl vanillin glucoside, 2-ethyl-3, (5 or 6)-dimethylpyrazine, 5-ethyl-3-hydroxy-4-methyl-2 (5H)-furanone, 2-ethyl-3-methylpyrazine, eucalyptol, fenugreek absolute, genet absolute, gentian root infusion, geraniol, geranyl acetate, grape juice, guaiacol, guava extract, γ-heptalactone, γ-hexalactone, hexanoic acid, cis-3-hexen-1-ol, hexyl acetate, hexyl alcohol, hexyl phenylacetate, honey, 4-hydroxy-3-pentenoic acid lactone, 4-hydroxy-4-(3-hydroxy-1-butenyl)-3,5,5-trimethyl-2-cyclohexen-1-one, 4-(para-hydroxyphenyl)-2-butanone, sodium 4-hydroxyundecanoate, immortelle absolute, β-ionone, isoamyl acetate, isoamyl butyrate, isoamyl phenylacetate, isobutyl acetate, isobutyl phenylacetate, jasmine absolute, kola nut tincture, labdanum oil, terpeneless lemon oil, licorice extract, linalool, linalyl acetate, lovage root oil, maltol, maple syrup, menthol, menthone, L-menthyl acetate, para-methoxybenzaldehyde, methyl-2-pyrrolyl ketone, methyl anthranilate, methyl phenylacetate, methyl salicylate, 4′-methylacetophenone, methylcyclopentenolone, 3-methylvaleric acid, mimosa absolute, molasses, myristic acid, nerol, nerolidol, γ-nonalactone, nutmeg oil, δ-octalactone, octanal, octanoic acid, orange flower oil, orange oil, orris root oil, palmitic acid, ω-pentadecalactone, peppermint oil, petitgrain Paraguay oil, phenethyl alcohol, phenethyl phenylacetate, phenylacetic acid, piperonal, plum extract, propenyl guaethol, propyl acetate, 3-propylidene phthalide, prune juice, pyruvic acid, raisin extract, rose oil, rum, sage oil, sandalwood oil, spearmint oil, styrax absolute, marigold oil, tea distillate, α-terpineol, terpinyl acetate, 5,6,7,8-tetrahydroquinoxaline, 1,5,5,9-tetramethyl-13-oxacyclo(8.3.0.0(4.9))tridecane, 2,3,5,6-tetramethylpyrazine, thyme oil, tomato extract, 2-tridecanone, triethyl citrate, 4-(2,6,6-trimethyl-1-cyclohexenyl) 2-buten-4-one, 2,6,6-trimethyl-2-cyclohexene-1,4-dione, 4-(2,6,6-trimethyl-1,3-cyclohexadienyl) 2-buten-4-one, 2,3,5-trimethylpyrazine, γ-undecalactone, γ-valerolactone, vanilla extract, vanillin, veratraldehyde, violet leaf absolute, N-ethyl-p-menthane-3-carboxamide (WS-3), and ethyl-2-(p-menthane-3-carboxamide) acetate (WS-5). Menthol is particularly preferred. These flavors may be used alone or in combination of two or more. The size of the shredded tobacco contained in the tobacco filler and the water content of the flavor source 24 are not particularly limited.

The flavor source 24 included in each thin rod 21 may contain no tobacco material. This type of flavor source 24 may be a plant material containing no tobacco component. In other words, each thin rod 21 may contain one or more selected from mesophyll, vein, stem, root, flower, seed, and pulp of a plant containing no tobacco component. A herbal material is a plant material containing no tobacco component suitable for use as the flavor source. Examples of the herbal material include allspice, allspice, black pepper, northern bugweed, calamus root, catmint, catuaba, cayenne pepper, chaga, chervil, cinnamon, Chinese ginseng, St. John's wort, green tea, black tea, black cohosh, cayenne, chamomile, amsonia, cocoa, honeybush, echinacea, feverfew, ginger, goldenseal, lavender, licorice, sweet marjoram, milk thistle, mint (menthe), oolong tea, oregano, pennyroyal, peppermint, red clover, rooibos (red or green), rosehip, rosemary, sage, clary sage, savory, spearmint, gotu kola, thyme, turmeric, valerian, wintergreen, yellow dock, yerba mate, yerba santa, Bacopa monniera, ashwagandha, capsicum, Chinese lantern plant, and marian thistle.

The flavor source included in each thin rod 21 may, of course, contain a mixture of the tobacco material and the above-described herbal material.

The aerosol-source material is a substance that is volatilized when heated by the heater of the flavor inhalation device 30 and releases a volatile substance that generates an aerosol when cooled. The aerosol-source material is, for example, liquid. The type of the aerosol-source material is not particularly limited, and extracts from various natural products and/or components thereof can be selected depending on the intended use. Examples of the aerosol-source material include glycerol, propylene glycol, triacetin, 1,3-butanediol, and mixtures thereof.

In the example illustrated in FIG. 3, each thin rod 21 has an elliptical cross-sectional shape with a minor axis extending in a radial direction of the flavor rod 2. More specifically, the minor axis of each thin rod 21 extends radially from the central axis CL of the flavor rod 2. The three thin rods 21 having an elliptical shape are arranged in contact with an inner surface 22A of the outer wrapping paper 22 such that a hollow section is formed in a central region of the flavor rod 2 in cross-section. In the following description, the hollow section formed in the central region of the flavor rod 2 in cross-section is referred to as a “heater insertion hole 25”. The heater insertion hole 25 is a hollow section into which the internal heater 32 of the flavor inhalation device 30 is inserted from the front end of the flavor rod 2. The heater insertion hole 25 extends from the front end to the rear end of the flavor rod 2 along the central axis CL. Each thin rod 21 may have a shape other than the elliptical shape.

The heater insertion hole 25 is defined (boundary thereof is determined) by outer surfaces 23A of the inner wrapping paper 23 of the plural thin rods 21 (three thin rods 21 in the present embodiment). More specifically, in the present embodiment, the heater insertion hole 25 in the flavor rod 2 is surrounded by the thin rods 21. In other words, the thin rods 21 are arranged around the heater insertion hole 25. The outer surfaces 23A of the inner wrapping paper 23 are surfaces opposite to the surfaces (inner surfaces) facing the flavor source 24. The heater insertion hole 25 illustrated in FIG. 3 has a shape similar to a triangular shape in cross-section. However, the shape of the heater insertion hole 25 is not particularly limited as long as the internal heater 32 can be inserted.

The mouthpiece 3 will now be described. The mouthpiece 3 includes a leakage-suppressing portion 4, a cooling portion 5, and a filter portion 6 arranged in that order from the front end. The leakage-suppressing portion 4, the cooling portion 5, and the filter portion 6 of the mouthpiece 3 are arranged coaxially, and wrapped together with wrapping paper 7. The wrapping paper 7 may be omitted, and the flavor rod 2, the leakage-suppressing portion 4, the cooling portion 5, and the filter portion 6 may be wrapped together with the tipping paper 8.

FIG. 4 is a perspective view of the leakage-suppressing portion 4 according to the first embodiment. The leakage-suppressing portion 4 is positioned immediately behind the flavor rod 2, and is disposed in contact with the rear end of the flavor rod 2. Reference sign CL2 denotes a central axis of the leakage-suppressing portion 4. The leakage-suppressing portion 4 has a hollow rod shape in which a through hole serving as an aerosol flow path 41 is formed in a central region in cross-section orthogonal to the central axis CL2.

In a cross-section of the flavor rod 2, outer peripheral gaps denoted by reference sign 26 in FIG. 3 are formed in an outer peripheral region adjacent to and inside the outer wrapping paper 22. The outer peripheral gaps 26 are gaps formed between the thin rods 21 that are adjacent to each other in the circumferential direction of the flavor rod 2, and extend from the front end 1b to the rear end of the flavor rod 2 along the central axis CL. As is clear from FIG. 3, the outer peripheral gaps 26 are formed at intersecting positions between the major axes of the thin rods 21 that are adjacent to each other in the circumferential direction of the flavor rod 2.

During inhalation from the flavor stick 1, air is introduced into the flavor rod 2 from the front end 1b and distributed between the thin rods 21. At this time, if the air introduced from the front end 1b of the flavor rod 2 passes through the outer peripheral gaps 26, the air flows into the mouthpiece 3 without passing through the flavor source 24 and serves as leakage air. Therefore, in the present embodiment, the leakage-suppressing portion 4 is disposed downstream of the flavor rod 2 to suppress or reduce the leakage of air through the outer peripheral gaps 26 in the flavor rod 2.

In FIG. 4, reference sign 42 denotes a blocking surface formed at the front end of the leakage-suppressing portion 4. The leakage-suppressing portion 4 has the blocking surface 42 (blocking portion) facing the outer peripheral gaps 26 in the flavor rod 2, thereby blocking the rear ends of the outer peripheral gaps 26. As a result, during inhalation from the flavor stick 1, the air introduced into the flavor rod 2 from the front end 1b can be restrained from leaking downstream through the outer peripheral gaps 26. Accordingly, the air introduced from the front end 1b during inhalation from the flavor stick 1 can be efficiently distributed to the flavor source 24 of each thin rod 21 and contribute to the generation of the aerosol.

The leakage-suppressing portion 4 may be formed of various materials. The leakage-suppressing portion 4 may be, for example, a hollow cellulose acetate tube. In other words, the leakage-suppressing portion 4 may be a cylindrical cellulose acetate fiber bundle having a center hole extending therethrough at the center thereof in cross-section. However, the material of the leakage-suppressing portion 4 is not particularly limited. It is not necessary that the material of the leakage-suppressing portion 4 have complete air impermeability as long as the ventilation resistance of the blocking surface 42 of the leakage-suppressing portion 4 is higher than that of the flavor source 24 in each thin rod 21 when the internal heater 32 is inserted in the heater insertion hole 25. Since air passes through regions where the ventilation resistance is relatively low, the leakage-suppressing portion 4 having the above-described structure functions effectively.

The blocking surface 42 (blocking portion) of the leakage-suppressing portion 4 extends along the thin rods 21 and the outer peripheral gaps 26. More specifically, a portion of the rear end of each thin rod 21 is in contact with the blocking surface 42 (blocking portion) of the leakage-suppressing portion 4, and is thereby supported from the rear. The remaining portion of the rear end of each thin rod 21 faces the aerosol flow path 41 in the leakage-suppressing portion 4. Accordingly, when the flavor rod 2 is inserted into the heating chamber in the flavor inhalation device 30 and the internal heater 32 is inserted into the heater insertion hole 25, the thin rods 21 are restrained from being pushed toward the rear of the stick due to the insertion resistance applied to the heater insertion hole 25 by the internal heater 32 (frictional resistance between the inner wrapping paper 23 around the heater insertion hole 25 and the internal heater 32). The leakage-suppressing portion 4 also functions as a spacer that separates the cooling portion 5 from the flavor rod 2.

The cooling portion 5 is positioned immediately downstream of the leakage-suppressing portion 4 and is disposed in contact with the rear end of the leakage-suppressing portion 4. During inhalation from the flavor stick 1, the volatile substance released from the flavor rod 2 (flavor source 24) flows downstream through the cooling portion 5. The volatile substance released from the flavor rod 2 (flavor source 24) accelerates the generation of the aerosol when cooled in the cooling portion 5. In the structure illustrated in FIG. 2, the cooling portion 5 is composed of a hollow paper tube having vent holes 5A that allow the introduction of outside air. It is not necessary that the cooling portion 5 have the vent holes 5A. The cooling portion 5 may be formed of a paper tube in which a cooling enhancement material, such as a polylactic acid sheet, is disposed to enhance the cooling of the volatile substance released from the flavor source 24. The cooling portion 5 may include a heat-absorbing agent disposed so as not to impede the flow of the volatile substance and the aerosol. For example, the cooling portion 5 may include a filter material having many flow paths (through holes) extending in the longitudinal direction (axial direction) of the mouthpiece 3.

The filter portion 6 is a segment positioned at the rear end of the mouthpiece 3, that is, adjacent to the mouthpiece end 1a. The filter portion 6 may be positioned immediately downstream of the cooling portion 5 and disposed in contact with the rear end of the cooling portion 5. In the structure illustrated in FIG. 2, the filter portion 6 may include, for example, a filter material that captures predetermined components of the aerosol. The type of the filter material included in the filter portion 6 is not particularly limited. For example, the filter portion 6 may include a filter material formed of cellulose acetate fibers shaped in a cylindrical shape. Alternatively, the filter portion 6 may be a center hole filter formed of cellulose acetate fibers shaped in a cylindrical shape and having a center hole extending along the axial direction. The filter portion 6 may also be a paper filter filled with cellulose fibers, or a paper tube including no filter element. The filter portion 6 may also be formed by selectively combining a solid filter material having a filter element, a center hole filter, a paper filter, and a paper tube including no filter element.

A method for manufacturing the flavor stick 1 according to the present embodiment will now be described. The method for manufacturing the flavor stick 1 includes: a step of forming the flavor rod by bundling plural thin rods, in each of which a flavor source containing an aerosol-source material is wrapped with inner wrapping paper, and wrapping the thin rods together with outer wrapping paper, the flavor rod having a heater insertion hole defined by outer surfaces of the inner wrapping paper of the thin rods, the heater insertion hole extending along an axial direction in a central region of the flavor rod in cross-section; and a connecting step in which the flavor rod and a mouthpiece are arranged in series and wrapped together with tipping paper. Here, the step of forming the flavor rod includes a long-thin-rod forming step in which plural long thin rods are formed in parallel with each other along a transport direction of a wrapping machine by wrapping the flavor source containing the aerosol-source material with long-sheet-shaped thin-rod wrapping paper continuously in a longitudinal direction; a long-flavor-rod forming step in which the long thin rods are joined and wrapped together with long outer wrapping paper to form a long flavor rod; and a cutting step in which the long flavor rod is cut to a predetermined length to form the flavor rod. This method will be described with reference to FIGS. 5 to 9.

FIG. 5 illustrates the steps for manufacturing the flavor stick 1 according to the first embodiment. FIG. 6 illustrates sections of a wrapping machine used to manufacture the flavor rod 2 according to the first embodiment. FIGS. 7 to 9 illustrate steps for manufacturing the flavor rod 2 according to the first embodiment. In an example described below, the flavor rod 2 including three thin rods 21 as illustrated in FIG. 3 is manufactured. The flavor rod 2 can be manufactured by using a known wrapping machine, such as the wrapping machine disclosed in Japanese Unexamined Patent Application Publication No. 7-184625.

First, in a thin-rod forming section 101 of the wrapping machine, long thin rods 21P1 to 21P3 that are long and have a cylindrical cross-sectional shape are formed by wrapping the flavor source 24 with long-sheet-shaped thin-rod wrapping paper 23P in a tubular shape continuously in the longitudinal direction (long-thin-rod forming step). The long thin rods 21P1 to 21P3 are long, and are finally cut to a predetermined length to form each thin rod 21.

FIG. 7 illustrates the long thin rods 21P1 to 21P3 formed in the thin-rod forming section 101. The thin-rod forming section 101 includes three parallel wrapping lines L1 to L3 that respectively wrap the long thin rods 21P1 to 21P3 in parallel with each other. The long thin rods 21P1 to 21P3 are wrapped in parallel with each other while moving along the lines in parallel with each other.

In the thin-rod forming section 101, each of the wrapping lines L1 to L3 has a flavor-source supply unit 101A and a shaping unit 101B positioned downstream of the flavor-source supply unit 101A. The flavor-source supply unit 101A of each of the wrapping lines L1 to L3 continuously supplies the flavor source 24 to the long inner wrapping paper 23P having a long strip shape transported along a transport path. The type of the flavor source 24 supplied from the flavor-source supply unit 101A to the long inner wrapping paper 23P may be the same or different between the wrapping lines L1 to L3. The shaping unit 101B of each of the wrapping lines L1 to L3 forms the long inner wrapping paper 23P into a tubular shape by gradually curling the long inner wrapping paper 23P inward after the flavor source 24 is applied thereto.

The shaping unit 101B causes the long inner wrapping paper 23P and the flavor source 24 to pass through a guide member having a tubular guide inner wall surface, thereby forming the long inner wrapping paper 23P into a tubular shape while the flavor source 24 is wrapped therewith. This type of guide member is commonly known. For example, a tongue disclosed in Japanese Unexamined Patent Application Publication No. 7-184625 may be used. For example, the tubular guide inner wall surface of the guide member has a diameter that gradually decreases toward the downstream side along the transport path, and the long inner wrapping paper 23P passes through the guide member while being guided by the tubular guide inner wall surface. As a result, the long inner wrapping paper 23P is formed into a U-shape in cross-section, and then into a tubular shape. When the long inner wrapping paper 23P is formed into a tubular shape, the flavor source 24 disposed inside the long inner wrapping paper 23P is appropriately compressed by the tubular guide inner wall surface. Thus, the long inner wrapping paper 23P is formed into a tubular shape, and end portions of the long inner wrapping paper 23P in the width direction are caused to overlap and bonded together. As a result, as illustrated in FIG. 7, the long thin rods 21P1 to 21P3 having a long cylindrical shape are obtained.

Next, in a thick-rod forming section 102 of the wrapping machine, the long thin rods 21P1 to 21P3 transported along the transport path are joined and wrapped together with long outer wrapping paper 22P to form a long flavor rod 2P that is long and has a cylindrical cross-sectional shape (long-flavor-rod forming step).

FIG. 8 illustrates the long thin rods 21P1 to 21P3 stacked on the long outer wrapping paper 22P having a long strip shape transported along the transport path in the thick-rod forming section 102. In the thick-rod forming section 102, the long outer wrapping paper 22P is formed into a tubular shape while the long thin rods 21P1 to 21P3 are stacked on the long outer wrapping paper 22P as illustrated in FIG. 8, and end portions of the long outer wrapping paper 22P in the width direction are caused to overlap and bonded together. As a result, as illustrated in FIG. 9, the long flavor rod 2P that is long and has a cylindrical cross-sectional shape is obtained.

Also when the long flavor rod 2P is formed in a cylindrical cross-sectional shape in the thick-rod forming section 102, a guide member similar to the above-described guide member used in the shaping unit 101B (for example, the tongue disclosed in Japanese Unexamined Patent Application Publication No. 7-184625) may be used. When the long outer wrapping paper 22P is formed into a tubular shape by the guide member, the long thin rods 21P1 to 21P3 positioned inside the long outer wrapping paper 22P are appropriately compressed by the tubular guide inner wall surface of the guide member. As a result, the cross-sectional shape of each of the long thin rods 21P1 to 21P3 can be changed from the initial circular shape (substantially perfectly circular shape) to an elliptical shape, and a hollow section 25P that serves as the heater insertion hole 25 can be formed in the space surrounded by the long thin rods 21P1 to 21P3. The long thin rods 21P1 to 21P3 may have the same diameter or different diameters before the compression. When the long thin rods 21P1 to 21P3 have the same diameter, the diameter of the long thin rods 21P1 to 21P3 before the compression may be set to about 3.5 mm to about 4 mm if, for example, the diameter of the flavor rod is 7 mm.

As described above, the long thin rods 21P1 to 21P3 are compressed from the outside and wrapped together with the long outer wrapping paper 22P to form the long flavor rod 2P. The long flavor rod 2P includes the long thin rods 21P1 to 21P3 having an elliptical cross-section inside the long outer wrapping paper 22P, and has the hollow section 25P (heater insertion hole 25) extending in the longitudinal direction in a central region thereof in cross-section.

Next, in a cutting section 103 of the wrapping machine, the long flavor rod 2P that is long and transported in the transport direction is sequentially cut to a predetermined length, for example, to the length corresponding to a single flavor rod (cutting step). As a result, the flavor rod 2 having the predetermined length is obtained. After the long flavor rod 2P is cut to the predetermined length, the cross-sectional shape of the flavor rod 2 may be checked, and feedback control may be performed to adjust the positions of the thin rods 21 in cross-section and the amount of the flavor source 24, for example.

To form the flavor stick 1, the mouthpiece 3 is separately prepared, and the flavor rod 2 and the mouthpiece 3 are connected by being wrapped together with the tipping paper 8 (connecting step). Thus, the flavor stick 1 illustrated in FIG. 2 is obtained.

The manufacturing method described above with reference to FIGS. 5 to 9 is hereinafter referred to as a “first manufacturing method”. A manufacturing method (second manufacturing method) that differs from the first manufacturing method will now be described. FIGS. 10 to 15 illustrate the second manufacturing method of the flavor stick 1. The second manufacturing method of the flavor stick 1 includes a step of forming the flavor rod and a connecting step. The step of forming the flavor rod includes a long-flavor-rod forming step and a cutting step. The step of forming the flavor rod of the second manufacturing method can be performed by using, for example, a known dual filter wrapping machine. FIG. 10 illustrates a front half of the long-flavor-rod forming step of the second manufacturing method. In FIG. 10, reference sign 110 denotes a conveyor that transports various materials used to manufacture the flavor stick 1 in the direction shown by the empty arrow in FIG. 10 (transport direction). As illustrated in FIG. 10, the long outer wrapping paper 22P is transported on the conveyor 110. FIG. 11 illustrates the shape of the conveyor 110 in cross-section orthogonal to the transport direction. The conveyor 110 has a concave groove 110A extending in the transport direction, and transports the long outer wrapping paper 22P and various other materials disposed in the groove 110A. For example, the groove 110A of the conveyor 110 has suction holes for applying suction to the long outer wrapping paper 22P at the bottom thereof, and the long outer wrapping paper 22P is transported while being deformed along the wall surface of the groove 110A.

In the second manufacturing method, various components used to form an intermediate assembly MA of the flavor stick 1 are supplied to the long outer wrapping paper 22P transported by the conveyor 110 of the wrapping machine. Reference sign 111 denotes a leakage-suppressing-component supply drum that supplies double-length leakage-suppressing members 4W to the long outer wrapping paper 22P on the transport path. Each double-length leakage-suppressing member 4W is cut by a cutting knife into two halves at the center thereof in the length direction, and is thereby divided into two leakage-suppressing portions 4. In other words, each double-length leakage-suppressing member 4W is a member obtained by increasing the length of the leakage-suppressing portion 4 to twice the ordinary length (length of the leakage-suppressing portion 4 in a final shape included in the flavor stick 1). The leakage-suppressing portion 4 corresponds to a “first component” that constitutes a portion of the mouthpiece 3. The first component may be a structural member disposed at the front end of the mouthpiece 3. The double-length leakage-suppressing members 4W, which are twice as long as the leakage-suppressing portion 4 (first component), correspond to “double-length first components”.

Reference signs 112 to 114 denote first to third thin-rod supply drums that supply double-length thin rods 21W1 to 21W3 to the long outer wrapping paper 22P transported by the conveyor 110. Each of the double-length thin rods 21W1 to 21W3 is cut by a cutting knife into two halves at the center thereof in the length direction, and is thereby divided into two thin rods 21. In other words, the double-length thin rods 21W1 to 21W3 are members obtained by increasing the length of the thin rods 21 to twice the ordinary length (length of the thin rods 21 in a final shape included in the flavor stick 1). In other words, each of the double-length thin rods 21W1 to 21W3 is substantially identical to a thin rod formed by wrapping the flavor source 24 with the inner wrapping paper 23 that is twice as long as the ordinary length.

As illustrated in FIG. 10, the leakage-suppressing-component supply drum 111 and the first to third thin-rod supply drums 112 to 114 are arranged in that order (at a first position P1 to a fourth position P4) from the upstream side along the transport path of the conveyor 110. The leakage-suppressing-component supply drum 111 and the first to third thin-rod supply drums 112 to 114 are, for example, positioned above the conveyor 110, and have drum rotational axes orthogonal to the transport direction of the conveyor 110. The leakage-suppressing-component supply drum 111 and the first to third thin-rod supply drums 112 to 114 rotate while components to be supplied to the long outer wrapping paper 22P transported by the conveyor 110 are retained thereon by suction, and successively supply the components to be supplied to the long outer wrapping paper 22P at a predetermined timing. The supply drums 111 to 114 successively receive various materials from, for example, hoppers and intermediate drums (not illustrated).

As illustrated in FIG. 10, the leakage-suppressing-component supply drum 111 at the first position P1 supplies the double-length leakage-suppressing members 4W to the long outer wrapping paper 22P at regular intervals. The intervals between the double-length leakage-suppressing members 4W supplied to the long outer wrapping paper 22P are substantially equal to the length of the double-length thin rods 21W1 to 21W3, and serve as rod-receiving spaces S1 in which the double-length thin rods 21W1 to 21W3 are to be placed. The first to third thin-rod supply drums 112 to 114 at the second to fourth positions P2 to P4 successively supply the double-length thin rods 21W1 to 21W3 to the rod-receiving spaces S1 between the double-length leakage-suppressing members 4W.

FIG. 12 illustrates the manner in which the leakage-suppressing-component supply drum 111 and the thin-rod supply drums 112 to 114 supply the respective components at the first to fourth positions P1 to P4. As described above, the double-length leakage-suppressing members 4W and the double-length thin rods 21W1 to 21W3 are successively supplied to the long outer wrapping paper 22P transported by the conveyor 110. When the double thin rod 21W3 is supplied to each rod-receiving space S1 at the fourth position P4, the three double thin rods 21W1 to 21W3 are bundled, and the bundles and the double-length leakage-suppressing members 4W are arranged in series on the long outer wrapping paper 22P (see, for example, FIGS. 10 and 12). Here, the term “bundle” means any arrangement in which the double-length thin rods 21W1 to 21W3 are parallel and close to each other.

FIG. 13 illustrates a second half of the long-flavor-rod forming step of the second manufacturing method. In the second half of the long-flavor-rod forming step, the double-length leakage-suppressing members 4W (double-length first components) and the bundles (denoted by reference sign 21W in FIG. 13) of the double-length thin rods 21W1 to 21W3 (double-length thin rods) arranged in series with the double-length leakage-suppressing members 4W are wrapped together with the long outer wrapping paper 22P. As a result, the bundles of the double-length thin rods 21W1 to 21W3 and the double-length leakage-suppressing members 4W are alternately arranged in the longitudinal direction and wrapped together with the long outer wrapping paper 22P to form a long flavor rod 2P′ having a long rod shape. The long flavor rod 2P′ includes sections referred to as “thin-rod sections ST1” in which the bundles of the double-length thin rods 21W1 to 21W3 are disposed and sections referred to as “leakage-component sections ST2” in which the double-length leakage-suppressing members 4W are disposed.

Similarly to the long-flavor-rod forming step of the first manufacturing method, the known tongue (guide member) described in Japanese Unexamined Patent Application Publication No. 7-184625 may be used to wrap the bundles of the double-length thin rods 21W1 to 21W3 and the double-length leakage-suppressing members 4W with the long outer wrapping paper 22P. Thus, the double-length thin rods 21W1 to 21W3 can be compressed from the outside and wrapped with the long outer wrapping paper 22P. As a result, the long flavor rod 2P′ is obtained. The long flavor rod 2P′ includes the double-length thin rods 21W1 to 21W3 having an elliptical cross-sectional shape in the thin-rod sections ST1, and has the hollow section 25P (heater insertion hole 25) extending in the longitudinal direction in a central region of each thin-rod section ST1 in cross-section.

The cutting step of the second manufacturing method will now be described. In FIG. 13, the conveyor 110 is omitted. In FIG. 13, reference sign 115 denotes a cutting knife of the wrapping machine. The cutting knife 115 cuts the long flavor rod 2P′ at the center of each double-length leakage-suppressing member 4W in the length direction and at the center of each of the double-length thin rods 21W1 to 21W3 in the length direction. In other words, in the cutting step, the long flavor rod 2P′ is cut at the center of each thin-rod section ST1 and at the center of each leakage-component section ST2. As described above, each of the double-length thin rods 21W1 to 21W3 is divided into two thin rods 21 by being cut at the center thereof in the length direction. Each of the double-length leakage-suppressing members 4W is divided into two leakage-suppressing portions 4 by being cut at the center thereof in the length direction. As a result of the above-described cutting step, the intermediate assembly MA (see FIG. 14), in which the leakage-suppressing portion 4 is connected to the rear end of the flavor rod 2 including the bundle of the thin rods 21, is formed. In the above-described example, one cutting knife 115 is used to cut the long flavor rod 2P′ in the cutting step. However, plural cutting knives 115 may be used to cut the long flavor rod 2P′. For example, a first cutting knife and a second cutting knife may be disposed at different positions along the transport direction of the conveyor 110. The first cutting knife may be used to cut the thin-rod sections ST1, and the second cutting knife may be used to cut the leakage-component sections ST2. Either the first cutting knife or the second cutting knife may be disposed upstream of the other in the transport direction of the conveyor 110.

FIG. 14 illustrates the intermediate assembly MA formed in the step of forming the flavor rod, and also illustrates the cooling portion 5, the filter portion 6, and the tipping paper 8 that are separately prepared. In FIG. 14, portions such as the leakage-suppressing portion 4, the cooling portion 5, and the filter portion 6 are simplified. The cooling portion 5 and the filter portion 6 correspond to “second components” that constitute a portion of the mouthpiece 3. The cooling portion 5 and the filter portion 6, which correspond to the second components, can also be regarded as components of the mouthpiece 3 other than the leakage-suppressing portion 4, which corresponds to the first component. The second manufacturing method of the flavor stick 1 includes the connecting step. In the connecting step of the second manufacturing method, the intermediate assembly MA and one or more second components that constitute a portion of the mouthpiece 3 are wrapped together with the tipping paper 8 while the one or more second components are arranged in series with the leakage-suppressing portion 4 of the intermediate assembly MA that corresponds to the first component. In this example, the cooling portion 5 and the filter portion 6 correspond to the second components. Therefore, as illustrated in FIG. 14, the cooling portion 5 and the filter portion 6 are arranged in series in that order from the rear end of the leakage-suppressing portion 4 of the intermediate assembly MA. In this state, the intermediate assembly MA, the cooling portion 5, and the filter portion 6 are connected together by being wrapped with the tipping paper 8. As a result, the flavor stick 1 is completed as illustrated in FIG. 15. In FIG. 15, the internal structures of the leakage-suppressing portion 4, the cooling portion 5, and the filter portion 6 are not illustrated.

The flavor inhalation device 30 illustrated in FIG. 1 is used for inhalation from the flavor stick 1 having the above-described structure. As illustrated in FIG. 1, the flavor inhalation device 30 includes the heating chamber 31, the internal heater 32, a power supply unit 33 that activates the internal heater 32 by supplying electric power thereto, and a controller 34 that controls the electric power supplied to the internal heater 32. The heating chamber 31 is a roughly cylindrical hollow portion defined by a chamber side peripheral wall 31B and a chamber bottom wall 31C, which constitute a portion of a housing of the flavor inhalation device 30. When the flavor stick 1 is inserted into the heating chamber 31, the flavor rod 2 is inserted through the insertion opening 31A from the front end 1b.

The internal heater 32 extends, for example, from the center of the chamber bottom wall 31C toward the insertion opening 31A in parallel with the axial direction of the heating chamber 31 (direction in which the flavor stick 1 is inserted and extracted). In other words, the central axis of the internal heater 32 coincides with the central axis of the heating chamber 31. In the example illustrated in FIG. 1, the internal heater 32 has a conical shape whose diameter gradually decreases from the base end thereof on the chamber bottom wall 31C toward the tip end thereof adjacent to the insertion opening 31A. However, the shape of the internal heater 32 is not particularly limited. For example, the internal heater 32 may have a truncated conical shape whose diameter gradually decreases from the base end thereof on the chamber bottom wall 31C toward the tip end thereof adjacent to the insertion opening 31A. The internal heater 32 may have a shape other than the conical shape or the truncated conical shape, for example, a cylindrical shape, a blade shape, or other shapes. The internal heater 32 is not limited to any particular type of electric heater. The internal heater 32 may be, for example, a steel material having heating wires (e.g., nichrome, iron-chrome, or iron-nickel wires) arranged thereover, a ceramic heater, or other heaters. The internal heater 32 is not limited to a heater based on resistance heating as described above. For example, the internal heater 32 may be a heating element referred to as a susceptor that produces heat by an induction heating (IH) method. When the induction heating method is used, a susceptor insertable into the heater insertion hole 25 in the flavor rod 2 may be placed in the heating chamber 31, and an induction coil for generating a high-frequency alternating magnetic field in the heating chamber 31 may be disposed around the heating chamber 31. In this case, the induction coil is activated to generate a high-frequency alternating magnetic field in the heating chamber 31, so that the susceptor in the heating chamber 31 produces heat to heat the flavor source 24 of each thin rod 21.

The flavor inhalation device 30 has an airflow path 36 that communicates with the chamber bottom wall 31C at one end thereof. The airflow path 36 communicates with an air inlet 37 formed in the housing of the flavor inhalation device 30 at the other end thereof.

The flavor inhalation device 30 may start the heating operation in response to a starting operation performed on, for example, an operation switch disposed on the housing. Alternatively, the flavor inhalation device 30 may start the heating operation in response to a detection of the insertion of the flavor stick 1 (flavor rod 2) into the heating chamber 31. For example, the controller 34 may include a sensor that detects the insertion of the flavor stick 1 (flavor rod 2) into the heating chamber 31, and start the heating operation in response to the detection of the insertion of the flavor stick 1 (flavor rod 2) by the sensor.

The power supply unit 33 is a power supply that supplies electric power for heating to the internal heater 32 through the controller 34. The controller 34 receives a request to start the heating operation in response to, for example, the operation on the operation switch or the detection of the insertion of the flavor stick 1 into the heating chamber 31, and causes the power supply unit 33 to supply the electric power to the internal heater 32.

The controller 34 may include a temperature sensor for detecting the temperature in the heating chamber 31 or the temperature of the flavor rod 2 and adjust the amount of current supplied from the power supply unit 33 to the internal heater 32 based on the temperature detected by the temperature sensor.

According to the flavor stick 1 of the present embodiment, the flavor rod 2 has the heater insertion hole 25 in a central region thereof in cross-section, and the heater insertion hole 25 extends along the central axis CL from the front end 1b. Therefore, when the flavor stick 1 (flavor rod 2) is inserted into the heating chamber 31, the internal heater 32 can be smoothly inserted into the heater insertion hole 25. In other words, the internal heater 32 can be attached to the flavor rod 2 with low attachment resistance. This improves the usability of the flavor stick 1 when the flavor rod 2 is attached to the heating chamber 31. In addition, when the internal heater 32 is inserted into the flavor rod 2, damage, such as bending or curving, to the internal heater 32 and buckling of the flavor rod 2 can be suppressed.

In addition, the flavor rod 2 of the present embodiment is structured such that the thin rods 21 formed by wrapping the flavor source 24 with the inner wrapping paper 23 are bundled together with the outer wrapping paper 22, and that the heater insertion hole 25 is defined (boundary thereof is determined) by the outer surfaces 23A of the inner wrapping paper 23 of the thin rods 21. Since the hollow portion for receiving the heater is not formed directly in the flavor source 24 and the outer periphery of the heater insertion hole 25 is defined by the outer surfaces 23A of the inner wrapping paper 23 of the thin rods 21 as described above, the inner wrapping paper 23 can be interposed between the heater insertion hole 25 and the flavor source 24. Accordingly, when the internal heater 32 is inserted into the heater insertion hole 25, the internal heater 32 comes into direct contact with the outer surfaces 23A of the inner wrapping paper 23, but not with the flavor source 24. Accordingly, when the internal heater 32 is attached to the flavor rod 2, soiling of the internal heater 32 by the flavor source 24 that adheres thereto can be suppressed. In other words, according to the flavor stick 1 of the present embodiment, the internal heater 32 can be attached to the flavor rod 2 with lower attachment resistance, and adhesion of the flavor source 24 to the internal heater 32 can be suppressed. This significantly improves the usability of the flavor stick 1. The heater insertion hole 25 in the flavor rod 2 may be expanded in cross-section by the internal heater 32 inserted therein. At this time, as a result of the expansion of the heater insertion hole 25 by the internal heater 32, each thin rod 21 is deformed such that the dimension thereof along the minor axis decreases. As a result, the dimension of each thin rod 21 along the major axis increases, so that the cross-sectional area of the outer peripheral gaps 26 can be reduced.

In addition, according to the above-described flavor stick 1 of the present embodiment, since the flavor source 24 in each of the thin rods 21 arranged around the heater insertion hole 25 is individually wrapped with the inner wrapping paper 23, the flavor source 24 of each thin rod 21 can be restrained from falling from the front end 1b. In, for example, a flavor rod in which the flavor source has no hollow portion for receiving the heater (referred to as Comparative Example 1), the flavor source is compressed by an amount corresponding to the volume of the internal heater when the internal heater is inserted into the flavor source, and the ventilation resistance is significantly increased. Therefore, according to Comparative Example 1, the amount of flavor source with which the flavor rod is filled needs to be adjusted (reduced) so that the ventilation resistance after the insertion of the internal heater into the flavor source (that is, ventilation resistance during inhalation) is within an appropriate range. However, when the amount of the flavor source is adjusted as described above in Comparative Example 1, the flavor rod may be too soft, and the hardness thereof may be insufficient for wrapping of the flavor rod using the wrapping machine. In contrast, according to the flavor rod 2 of the present embodiment, the flavor source 24 of each thin rod 21 is individually wrapped with the inner wrapping paper 23. Therefore, even when the amount of the flavor source 24 with which each thin rod 21 is filled is small, the flavor rod 2 can have an appropriate overall hardness, and the flavor rod 2 is suitable for manufacturing using the wrapping machine.

In the flavor stick 1 having the above-described structure, the flavor source 24 of each thin rod 21 is heated when the internal heater 32 is activated while the flavor rod 2 is inserted in the heating chamber 31 of the flavor inhalation device 30. As a result, the aerosol-source material contained in the flavor source 24 is volatilized, and the flavor source 24 releases a flavor component, so that an aerosol containing the flavor component is generated. The aerosol containing the flavor component flows through each thin rod 21 toward the mouthpiece 3 (downstream), and enters the mouthpiece 3 from the rear end of each thin rod 21. The aerosol containing the flavor component successively flows through the aerosol flow path 41 in the leakage-suppressing portion 4 at the front end of the mouthpiece 3, the cooling portion 5, and the filter portion 6, and is finally inhaled into the oral cavity of the user from the mouthpiece end 1a.

The flavor stick 1 includes the leakage-suppressing portion 4 disposed in a front end section of the mouthpiece 3. The leakage-suppressing portion 4 has the aerosol flow path 41 extending in the axial direction to allow the aerosols generated in the thin rods 21 to flow therethrough, and the blocking surface 42 (blocking portion) that faces the outer peripheral gaps 26 in the flavor rod 2. Thus, during inhalation from the flavor stick 1, the air introduced into the flavor rod 2 from the front end 1b can be restrained from leaking downstream through the outer peripheral gaps 26. The position, size, number, etc., of the aerosol flow path 41 in the leakage-suppressing portion 4 are not particularly limited as long as the aerosol from each thin rod 21 can flow downstream. For example, as in a modification illustrated in FIG. 16, the leakage-suppressing portion 4 may have aerosol flow paths 41A to 41C extending in the axial direction to allow the aerosol from each thin rod 21 to flow individually. The aerosol flow paths 41A to 41C are disposed to face the respective ones of the three thin rods 21 of the flavor rod 2 to allow the aerosols from the thin rods 21 to individually flow therethrough.

As described above, the leakage-suppressing portion 4 of the present embodiment also functions as a stopper (support member) that supports the thin rods 21 from the rear and restrains the thin rods 21 from being pushed toward the rear of the stick. Therefore, even when frictional resistance occurs between the inner wrapping paper 23 and the internal heater 32 upon insertion of the internal heater 32 into the heater insertion hole 25 in the flavor rod 2, the thin rods 21 can be restrained from being pushed toward the rear of the stick.

Another method that can be used to restrain the thin rods 21 from being displaced as described above is to bond the outer surfaces 23A of the inner wrapping paper 23 of the thin rods 21 to the inner surface 22A of the outer wrapping paper 22. For example, when the flavor rod 2 is manufactured, glue (referred to as “rail glue” in the technical field) is used to bond the long inner wrapping paper 23P of each of the long thin rods 21P1 to 21P3 to the long outer wrapping paper 22P for bundling the long thin rods 21P1 to 21P3. The glue is applied to the inner surface of the long outer wrapping paper 22P along lines extending in the longitudinal direction of the long outer wrapping paper 22P. Then, the long thin rods 21P1 to 21P3 are wrapped with the long outer wrapping paper 22P. When the outer surface 23A of the inner wrapping paper 23 of each thin rod 21 is bonded to the inner surface 22A of the outer wrapping paper 22 as described above, each thin rod 21 can be restrained from being displaced. When the inner wrapping paper 23 of each thin rod 21 is bonded to the outer wrapping paper 22, the leakage-suppressing portion 4 may be omitted as long as air leakage through the outer peripheral gaps 26 is allowable.

The thin rods 21 included in the flavor rod 2 may include the flavor source 24 of the same type or different types. When the thin rods 21 include the flavor source 24 of different types, a first one of the thin rods 21 included in the flavor rod 2 may, for example, include the flavor source 24 that fills the space inside the inner wrapping paper 23 in the form of a uniformized sheet folded in a gathered form. A second one of the thin rods 21 may, for example, include the flavor source 24 that fills the space inside the inner wrapping paper 23 in the form of shredded tobacco. A third one of the thin rods 21 may, for example, include a plant material (for example, a herbal material) containing no tobacco component that fills the space inside the inner wrapping paper 23 as the flavor source 24. The above-described combination is, of course, an example. When at least one of the thin rods 21 included in the flavor rod 2 includes the flavor source 24 of the type different from that in the other thin rods 21, the flexibility in designing smoke flavor and taste can be increased, and rich smoke flavor and taste can be more easily produced.

When the thin rods 21 of the flavor rod 2 contain the flavor source 24 of different types as described above, the thin rods 21 may have different cross-sectional areas. In such a case, the content of the flavor source 24 can be easily controlled based on the type of the flavor source 24.

The outer periphery of the flavor source 24 of each of the thin rods 21 included in the flavor rod 2 is covered by the inner wrapping paper 23. Therefore, the aerosol containing the flavor component released from the flavor source 24 of each thin rod 21 is basically introduced into the mouthpiece 3 without being mixed with the other aerosols. Accordingly, when the thin rods 21 include the flavor source 24 of different types, the different types of flavor source 24 can release aerosols containing flavor components with more distinct flavors. In this regard, the mouthpiece 3 may have a flow path structure that guides the aerosols from the thin rods 21 individually to the mouthpiece end 1a. In such a case, for example, as in the example illustrated in FIG. 16, the leakage-suppressing portion 4 may have the aerosol flow paths 41A to 41C extending in the axial direction to individually allow the aerosols from the thin rods 21 to flow therethrough. In addition, the cooling portion 5 may, for example, include a sheet folded in a gathered form that defines flow paths extending in the axial direction of the mouthpiece 3 so that the aerosols from the thin rods 21 are not easily mixed.

In addition, the flavor rod 2 of the present embodiment includes the thin rods 21 arranged around the heater insertion hole 25. Accordingly, in cross-section of the flavor rod 2, the heater insertion hole 25 can be disposed in the central region, and the region around the central region can be effectively used as the region in which the thin rods 21 are arranged.

In addition, each thin rod 21 of the flavor rod 2 has an elliptical cross-sectional shape with a minor axis extending in a radial direction of the flavor rod 2. Since each thin rod 21 having an elliptical cross-section is oriented such that the minor axis thereof extends in a radial direction of the flavor rod 2, the region in which the heater insertion hole 25 is formed can be easily provided in the central region of the flavor rod 2 in cross-section. In addition, according to the above-described embodiment, each thin rod 21 can be easily disposed so that the major axis thereof extends along the circumferential direction of the flavor rod 2, and the area of the outer peripheral gaps 26 can be reduced.

In the present embodiment, the ratio of the cross-sectional area of the heater insertion hole 25 to the cross-sectional area of the flavor rod 2 is not particularly limited, and may be, for example, 2% or more, preferably 5% or more. In this case, when the internal heater 32 is inserted into the heater insertion hole 25, the occurrence of excessive frictional resistance between the inner wrapping paper 23 and the internal heater 32 can be more effectively suppressed. Thus, wrinkling or tearing of the inner wrapping paper 23 disposed around the heater insertion hole 25 can be reliably suppressed, and the thin rods 21 can be restrained from being pushed toward the rear of the stick even when the flavor stick 1 does not include the leakage-suppressing portion 4.

In addition, as described above, the number of thin rods 21 included in the flavor rod 2 is not particularly limited as long as two or more thin rods 21 are provided. However, to facilitate formation of the heater insertion hole 25 and reduce the area of the outer peripheral gaps 26 in the flavor rod 2, three or more thin rods 21 are preferably provided. The number of thin rods 21 may be changed along the axial direction of the flavor rod 2. For example, three thin rods 21 may be disposed adjacent to the front end of the flavor rod 2, and two thin rods 21 may be disposed adjacent to the rear end of the flavor rod 2.

In the present embodiment, the inner wrapping paper 23 of each thin rod 21 is preferably made of a material with a high heat transfer performance to ensure efficient transmission of heat from the internal heater 32 to the flavor source 24 disposed inside the inner wrapping paper 23. Therefore, the inner wrapping paper 23 is preferably made of a low-basis-weight, high-density material. For example, the inner wrapping paper 23 preferably has a basis weight of 10 gsm or more and 40 gsm or less and a density of 1 g/cm³ or more and 1.5 g/cm³ or less. A coating agent, such as pectin or sodium alginate, may be applied to the inner wrapping paper 23 to improve the heat transfer performance. The inner wrapping paper 23 may be composed of a material having a high heat transfer performance, such as aluminum-laminated paper.

The inner wrapping paper 23 is preferably made of a low-air-permeability material to suppress leakage of the aerosol through the outer peripheral gaps 26. For example, the inner wrapping paper 23 may have an air permeability of 0 CORESTA unit (CU) or more and 200 CORESTA unit (CU) or less. The above-described air permeability may be measured in accordance with, for example, ISO 2965:2009.

To suppress tearing of the inner wrapping paper 23 when the internal heater 32 is inserted into or extracted from the heater insertion hole 25, the coefficient of static friction between the internal heater 32 and the inner wrapping paper 23 is preferably adjusted to 0.45 or more and 0.75 or less, and the coefficient of kinetic friction between the internal heater 32 and the inner wrapping paper 23 is preferably adjusted to 0.4 or more and 0.7 or less. In addition, to suppress tearing of the inner wrapping paper 23 when the internal heater 32 is inserted or extracted, the tensile strength of the inner wrapping paper 23 is preferably 10 to 20 N/15 mm, and the wet tensile strength of the inner wrapping paper 23 is preferably 5 to 20 N/15 mm. The tensile strength of the inner wrapping paper 23 is measured in accordance with, for example, JIS P 8113. The wet tensile strength of the inner wrapping paper 23 may be measured based on, for example, a wet tensile strength test described in Japanese Unexamined Patent Application Publication No. 2019-187451.

To suppress the escape of heat from the heating chamber 31 to the outside, the outer wrapping paper 22 of the flavor rod 2 preferably has a low heat transfer performance. Therefore, the outer wrapping paper 22 is preferably made of a low-basis-weight, low-density material. For example, the outer wrapping paper 22 preferably has a basis weight of 10 gsm or more and 40 gsm or less and a density of 0.5 g/cm³ or more and 1 g/cm³ or less. A coating agent, such as calcium carbonate or silicon dioxide, may be applied to the outer wrapping paper 22 to reduce heat transfer.

Each thin rod 21 preferably has a hardness of 60% or more and 85% or less when the space inside the inner wrapping paper 23 is filled with the flavor source 24. Here, the term “hardness” means the resistance to deformation of the thin rod 21 along cross-section. The hardness of the thin rod 21 can be measured based on, for example, the test method described in Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2019-506868 (paragraphs 0029-0031, FIG. 1). The test for measuring the hardness of the thin rod 21 can be performed in accordance with the standard operation procedure for Borgwaldt Hardness Tester H10 (produced by Heinr Borgwaldt GmbH).

More specifically, the hardness of the thin rod 21 can be determined by the following equation:

$\mathrm{Hardness}\left(\%\right)=\left(\mathrm{Dd}/\mathrm{Ds}\right)\times 100$

In the equation, Ds is the height of the thin rod 21 in the radial direction before a load is applied by the Borgwaldt Hardness Tester H10, and Dd is the height of the thin rod 21 in the radial direction after a constant load (88 g) is applied to the thin rod 21 in the radial direction for a predetermined load time (5 seconds) by a load bar of Borgwaldt Hardness Tester H10. FIG. 17 is a schematic diagram illustrating the measurement of the hardness of the thin rod 21. In FIG. 17, reference sign F denotes the load applied to the thin rods 21 in the radial direction in the measurement test. Reference sign d denotes the amount by which the thin rod 21 is pressed downward in the radial direction by the load applied by the load bar (d=Ds−Dd). The harder the thin rod 21 (the smaller the amount of depression), the closer the hardness is to 100%.

<First Modification>

A first modification of the flavor rod 2 according to the first embodiment will now be described. FIG. 18 illustrates a cross-section of a flavor rod 2A according to a modification of the first embodiment. As illustrated in FIG. 18, the flavor rod 2A according to the first modification includes two thin rods 21. As illustrated in FIG. 18, the basic structure of the flavor rod 2A including two thin rods 21 (two-thin-rod type) is similar to that of the above-described flavor rod 2 including the three thin rods 21 (three-thin-rod type). More specifically, the flavor rod 2A has the heater insertion hole 25 in a central region thereof in cross-section, and the two thin rods 21 are arranged to surround the heater insertion hole 25.

In FIG. 18, structures similar to those in the above-described embodiment are denoted by the same reference signs, and detailed description thereof is thus omitted. The heater insertion hole 25 differs from that illustrated in FIG. 3 in that the cross-sectional shape thereof is circular. However, the shape of the heater insertion hole 25 is not particularly limited. In the example illustrated in FIG. 18, each of the pair of thin rods 21 has an elliptical cross-sectional shape with a roughly semicircular cut in a portion thereof. As illustrated in FIG. 18, the pair of thin rods 21 are disposed such that the semicircular cuts are adjacent to the central axis CL of the flavor rod 2A and face each other, and such that the major axes thereof are parallel to each other. The semicircular cuts in the pair of thin rods 21 are combined to form the circular heater insertion hole 25. The minor axes of the pair of thin rods 21 each extend in a radial direction of the flavor rod 2A. More specifically, the minor axes are on the same straight line that passes through the central axis CL.

The flavor rod 2A illustrated in FIG. 18 is also integrally connected to the mouthpiece 3 with the above-described tipping paper 8 to form the flavor stick 1 (see FIG. 2). The flavor rod 2A according to the present modification can basically be manufactured by steps similar to those for manufacturing the flavor rod 2 of the three-thin-rod type. The two-thin-rod type differs, of course, from the three-thin-rod type in that the number of thin rods 21 is two. Therefore, in the present modification, two long thin rods 21P1 and 21P2 are provided in the above-described long-thin-rod forming step. Assuming the diameter of the flavor rod 2A to be manufactured is 7 mm, the diameter of the two long thin rods 21P1 and 21P2 (before compression) may be set to about 4 mm to about 4.5 mm.

In the present modification, when the two long thin rods 21P1 and 21P2 are joined in the thick-rod forming section 102 of the wrapping machine, a core rod member called a mandrel is placed between the two long thin rods 21P1 and 21P2. The mandrel has a cross-section corresponding to that of the heater insertion hole 25, and is formed as a cylindrical rod in the present modification. In the thick-rod forming section 102, the two long thin rods 21P1 and 21P2 are caused to pass through the above-described guide member while the mandrel is disposed therebetween. Thus, the two long thin rods 21P1 and 21P2 are compressed from the inside and outside by the tubular guide inner wall surface of the guide member and the mandrel while the long outer wrapping paper 22P is formed into a tubular shape to wrap the long thin rods 21P1 and 21P2 together. At this time, the two long thin rods 21P1 and 21P2 are compressed in the above-described shaping process such that, as illustrated in FIG. 19, the cross-sectional shapes thereof are changed to elliptical shapes having roughly semicircular recesses 25P1 and 25P2 in portions thereof. The pair of recesses 25P1 and 25P2 are combined to form the heater insertion hole 25 in the flavor rod 2A. In FIG. 19, reference sign M denotes a cross-section of the mandrel (core rod member).

In the flavor rod 2A according to the present modification, the area of the outer peripheral gaps 26 can be reduced by arranging the major axes of the pair of thin rods 21 parallel to each other. In addition, the heater insertion hole 25 can be easily formed in the central region of the flavor rod 2A in cross-section by forming the recesses 25P1 and 25P2 in the long thin rods 21P1 and 21P2 in advance by using the above-described mandrel (core rod member) when the flavor rod 2A is manufactured. The mandrel (core rod member) used in the present modification may also be used when the above-described flavor rod 2 of the three-thin-rod type is manufactured.

In the above-described flavor rods 2 and 2A, the space inside the inner wrapping paper 23 of each thin rod 21 is filled with the flavor source 24. However, the flavor source is not necessarily provided in this form, and may be provided in various forms as long as the flavor source and the aerosol-source material are disposed in the space inside the inner wrapping paper 23.

FIG. 20 illustrates a cross-section of a flavor rod 2B according to a second modification of the first embodiment. The flavor rod 2B according to the second modification differs from that of the above-described embodiment only in the form of the flavor source containing the aerosol-source material disposed inside the inner wrapping paper 23 of each thin rod 21, and other structures are similar to those of the above-described embodiment.

In FIG. 20, reference sign 24A denotes a flavor source disposed inside the inner wrapping paper 23. The flavor source 24A contains the flavor source, the aerosol-source material, and a holding substrate 240 that holds the flavor source and the aerosol-source material. In the present modification, the flavor source may be, for example, the above-described flavoring agent. For example, the holding substrate 240 of the flavor source 24A is a substrate sheet impregnated with a liquid flavoring agent and a liquid aerosol-source material, and the material of the holding substrate may be, for example, a nonwoven fabric. The flavoring agent with which the holding substrate 240 (substrate sheet) of the flavor source 24A is impregnated may contain no tobacco component. The holding substrate 240 (substrate sheet) of the flavor source 24A may, for example, be bonded to the inner surface of the inner wrapping paper 23 of each thin rod 21. The thickness of the holding substrate 240 (substrate sheet) is not particularly limited, and may be, for example, about 0.1 mm to about 2 mm. To manufacture the flavor rod 2B according to the present modification, in the above-described long-thin-rod forming step, plural long thin rods may be formed in parallel with each other along the transport direction of the wrapping machine by wrapping a long sheet-shaped substrate sheet impregnated with the flavor source and the aerosol-source material with long-sheet-shaped thin-rod wrapping paper into a tubular shape continuously in the longitudinal direction. The long-flavor-rod forming step and the cutting step performed subsequently are similar to those in the above-described embodiment.

The thin rods 21 may include the flavor source 24A containing the flavor source (flavoring agent) of the same type or different types. Although the holding substrate 240 (substrate sheet) of the flavor source 24A of each thin rod 21 has a tubular cross-sectional shape in the example illustrated in FIG. 20, the cross-sectional shape is not limited to this. The holding substrate 240 (substrate sheet) may have any cross-sectional shape, such as a C-shape, an S-shape, or a spiral shape. A substrate sheet impregnated with a liquid flavoring agent and an aerosol-source material may be shredded into small pieces, and the space inside the inner wrapping paper 23 may be filled with these pieces. One or more of the thin rods 21 included in the flavor rod 2B may, of course, be replaced with the thin rods 21 including the flavor source 24 composed of the tobacco filler described with reference to FIG. 3.

FIG. 21 illustrates variants of the flavor source 24A of each thin rod 21. In FIG. 21, (a) shows a flavor source 24A (holding substrate 240) having a C-shape; (b) shows a flavor source 24A (holding substrate 240) having an S-shape; (c) shows a flavor source 24A (holding substrate 240) having a meandering shape; and (d) shows a flavor source 24A (holding substrate 240) having a spiral shape. The variants illustrated in FIG. 21 are, of course, also examples of the flavor source 24A (holding substrate 240).

Although an embodiment of the present invention has been described above, the flavor stick, the non-combustion-heating-type flavor inhalation product, and the method for manufacturing the flavor stick according to the present invention are not limited to the above-described embodiment. Various modes disclosed in the above-described embodiment and modifications may be combined with any other modes disclosed in this specification.

REFERENCE SIGNS LIST

• • 1 flavor stick
  • 2 flavor rod
  • 3 mouthpiece
  • 21 thin rod
  • 22 outer wrapping paper
  • 23 inner wrapping paper
  • 24 flavor source
  • 25 heater insertion hole

Claims

1. A flavor stick comprising:

a flavor rod configured to be inserted into a heating chamber of a flavor inhalation device and heated by an internal heater of the flavor inhalation device; and

a mouthpiece connected to a rear end of the flavor rod,

wherein the flavor rod includes a plurality of thin rods and outer wrapping paper with which the plurality of thin rods are bundled and wrapped,

wherein each of the plurality of thin rods includes inner wrapping paper and a flavor source, the flavor source being disposed inside the inner wrapping paper and containing an aerosol-source material,

wherein the flavor rod has a heater insertion hole in a central region of the flavor rod in cross-section, the heater insertion hole extending in an axial direction and allowing the internal heater to be inserted into the heater insertion hole from a front end of the flavor rod, and

wherein the heater insertion hole is defined by outer surfaces of the inner wrapping paper of the plurality of thin rods.

2. The flavor stick according to claim 1, wherein the plurality of thin rods are arranged around the heater insertion hole in cross-section of the flavor rod.

3. The flavor stick according to claim 1, wherein the inner wrapping paper of each of the plurality of thin rods is bonded to the outer wrapping paper.

4. The flavor stick according to claim 1, wherein each of the plurality of thin rods has an elliptical cross-sectional shape with a minor axis extending in a radial direction of the flavor rod.

5. The flavor stick according to claim 1, wherein the mouthpiece includes a leakage-suppressing portion in a front end section thereof, the leakage-suppressing portion being connected to a rear end of the flavor rod and including an aerosol flow path and a blocking portion, the aerosol flow path extending in the axial direction and allowing an aerosol generated in the plurality of thin rods to flow therethrough, the blocking portion blocking a rear end of a gap formed between adjacent ones of the thin rods.

6. The flavor stick according to claim 5, wherein the blocking portion extends along the thin rods and the gap and serves as a stopper in regions in which the blocking portion faces the thin rods, the stopper restraining the thin rods from being displaced when the internal heater is inserted.

7. A non-combustion-type flavor inhalation product comprising:

the flavor stick according to claim 1; and

a flavor inhalation device used for inhalation from the flavor stick, the flavor inhalation device including a heating chamber that allows insertion of the flavor rod of the flavor stick and an internal heater inserted into the heater insertion hole when the flavor rod is inserted into the heating chamber.

8. A method for manufacturing a flavor stick including a flavor rod having a heater insertion hole in a central region of the flavor rod in cross-section and a mouthpiece connected to a rear end of the flavor rod, the heater insertion hole allowing an internal heater of a flavor inhalation device to be inserted into the heater insertion hole, the method comprising:

a step of forming the flavor rod by bundling a plurality of thin rods, in each of which a flavor source containing an aerosol-source material is wrapped with inner wrapping paper, and wrapping the plurality of thin rods together with outer wrapping paper, the flavor rod having the heater insertion hole defined by outer surfaces of the inner wrapping paper of the thin rods, the heater insertion hole extending along an axial direction in the central region of the flavor rod in cross-section; and

a connecting step in which the flavor rod and the mouthpiece are arranged in series and wrapped together with tipping paper.

9. The method for manufacturing the flavor stick according to claim 8,

wherein the step of forming the flavor rod includes a long-thin-rod forming step in which a plurality of long thin rods are formed in parallel with each other along a transport direction of a wrapping machine by wrapping the flavor source containing the aerosol-source material with long-sheet-shaped thin-rod wrapping paper continuously in a longitudinal direction, a long-flavor-rod forming step in which the plurality of long thin rods are joined and wrapped together with long outer wrapping paper to form a long flavor rod, and a cutting step in which the long flavor rod is cut to a predetermined length to form the flavor rod.

10. The method for manufacturing the flavor stick according to claim 8,

wherein the step of forming the flavor rod includes a long-flavor-rod forming step in which a long flavor rod is formed by supplying double-length first components, each of which is twice as long as a first component that constitutes a portion of the mouthpiece, to long-sheet-shaped long outer wrapping paper at regular intervals while the long outer wrapping paper is transported along a transport path of a wrapping machine, supplying a plurality of double-length thin rods, which are twice as long as the thin rods, to rod-receiving spaces formed between the double-length first components to form bundles of the double-length thin rods, and then wrapping together the double-length first components and the bundles of the double-length thin rods arranged in series with the long outer wrapping paper, and a cutting step in which the long flavor rod is cut at centers of the double-length first components in a length direction and centers of the double-length thin rods in the length direction to form intermediate assemblies in each of which the flavor rod is connected to the first component, and

wherein, in the connecting step, one of the intermediate assemblies and one or more second components that constitute another portion of the mouthpiece are wrapped together with the tipping paper while the one or more second components are arranged in series with the first component of the one of the intermediate assemblies.