WO2016021021A1 - Cigarette with filter - Google Patents

Abstract

The present invention provides technology for, in a cigarette with a filter, making tar soiling not stand out easily on the inhalation opening end surface and suppressing occurrences of insufficient hardness in the filter. A cigarette with a filter is provided with a tobacco rod containing chopped tobacco and a filter connected to an end part of the tobacco rod via tip paper, and is characterized in that the filter has an inhalation opening end section disposed at the inhalation opening end, said inhalation opening end section including a fiber bundle formed in a cylindrical shape and a first smoke flow path passing through the fiber bundle in the longitudinal direction, and a pre-stage section linked to the front end of the inhalation opening end section, said pre-stage section including a fiber bundle formed in a cylindrical shape and a second smoke flow path passing through the fiber bundle in the longitudinal direction, and in that the flow path cross-sectional area of the first smoke flow path is larger than the flow path cross-sectional area of the second smoke flow path.

Description

Cigarette with filter

The present invention relates to a cigarette with a filter.

A cigarette with a filter adjusts the balance between air dilution by introducing ventilation air from the air vents formed in the outer periphery of the filter and filtration with a filter medium, so that tar, nicotine, and CO (carbon monoxide) Control (adjustment) of the components in the smoke of cigarettes is performed.

By the way, since CO is a gas phase component, it is not filtered by a filter medium, and the concentration in the smoke is reduced by dilution with air. On the other hand, tar is reduced by both filtration with a filter medium and dilution with air. Thus, as a design method for a cigarette with a filter, there is a case where a low filtration and high dilution design that lowers the filtration ratio by the filter medium and increases the dilution ratio may be performed. According to this low filtration and high dilution design, the CO ratio with respect to tar can be lowered, and an effect of improving the flavor by increasing the feeling of sucking can be expected.

Various methods are adopted to realize a low filtration and high dilution design. For example, there is a known technique to increase the dilution ratio by increasing the diameter of the ventilation hole into which ventilation air is introduced by reducing the ventilation resistance of mainstream smoke by increasing the fiber diameter of the filter medium to lower the density. It has been. However, there is a limit to reducing the airflow resistance of the filter medium by the above method due to restrictions on the circumferential length of the cigarette, the filter length, the material used for the filter medium, and the like.

Therefore, a design method that arranges a section that does not have a mainstream smoke filtering function in a part of the filter, for example, a center hole filter with a through hole in the center of the shaft, or a recess in a part of the filter. A design method for realizing low filtration and high dilution by forming a cavity and a cavity has been proposed.

JP-A-5-23158

However, simply providing a non-filtering section that does not have a mainstream smoke filtering function in a part of the filter can realize low filtration and high dilution of the mainstream smoke, but may cause the following problems. For example, when a center hole filter is employed, there is a problem that tar is likely to locally adhere to the periphery of the center hole at the mouth end surface, and tar dirt on the mouth end surface is likely to be noticeable after smoking. On the other hand, when a recess is formed on the mouth end side of the filter or a cavity is formed in the middle portion, the filter is liable to be insufficient in hardness.

The present invention has been made in view of the above-mentioned problems, and its purpose is to make the tar dirt on the end face of the mouthpiece less noticeable and to suppress the occurrence of insufficient filter hardness in a cigarette with a filter. Is to provide.

In order to solve the above-mentioned problems, the present invention is for flowing mainstream smoke into each of a suction end section disposed at a suction end of a filter and a front section connected to the front end of the suction end section. A through passage was formed, and the flow passage cross-sectional area of the through passage in the suction end section was made larger than the flow passage cross-sectional area of the through passage in the preceding section.

More specifically, a cigarette with a filter according to the present invention is a cigarette with a filter comprising a cigarette rod including a cigarette and a filter connected to an end of the cigarette rod through a chip paper, The filter is a mouth end section disposed at the mouth end, and a mouth end section provided with a fiber bundle in which a through passage for flowing mainstream smoke is formed along the axial direction, and the mouth end A front section connected to the front end of the section, and a front section provided with a fiber bundle in which a through passage for flowing mainstream smoke is formed along the axial direction. The cross-sectional area of the through passage is larger than the cross-sectional area of the through passage in the preceding section.

According to the present invention, in the cross-sectional area of the through passage in the mouth end section, the outer peripheral side that does not overlap the through passage in the front section in the axial direction as compared with the central region overlapping the through passage in the front section in the axial direction. The flow velocity (flow rate) of the mainstream smoke flowing through the region is relatively slow (decreased). Thereby, when mainstream smoke is attracted | sucked in the oral cavity from the rear end of the through-passage in a suction end section, the frequency (opportunity) which a suction mouth end surface of a filter and mainstream smoke contact can be reduced. As a result, it is difficult for local tar adhesion to occur around the through-passage (edge) on the end face of the mouthpiece. Therefore, tar dirt on the end face of the mouthpiece in the filter can be suppressed, making it less noticeable. Further, according to the present invention, it is not necessary to provide a section such as a cavity or a recess in the filter, so that it is possible to prevent the filter from being insufficiently hard.

In the present invention, the length of the mouth end section may be shorter than the length of the preceding section. By comprising in this way, it becomes possible to suppress more reliably that the lack of hardness of the filter becomes obvious.

In the present invention, the through-passages in the mouth end section and the front section may be coaxially arranged. By comprising in this way, it becomes possible to make tar dirt of the mouth end face in a filter more difficult to stand out.

Further, in the present invention, a spillage suppressing means for suppressing the tobacco stamp from entering the filter may be provided at the front end of the filter. By comprising in this way, it can suppress suitably that the tobacco stamp in a tobacco rod approachs into a filter.

In the present invention, a filter medium including a fiber bundle that filters mainstream smoke is disposed at the front end of the filter, and the filter medium may also serve as the spillage suppression means. By comprising in this way, the material cost of a filter can be reduced and it can also suppress that the manufacturing process of a filter becomes complicated.

In the present invention, the chip paper is formed with a vent hole for introducing outside air into the filter to dilute mainstream smoke, and the vent hole is upstream of the suction end section in the filter. It may be arranged on the side. By configuring in this way, there is an advantage that mainstream smoke can be easily moved to the center side in the preceding section.

In addition, the means for solving the problems in the present invention can be employed in combination as much as possible.

According to the present invention, in the cigarette with a filter, it is possible to provide a technique that makes the tar dirt on the end face of the mouthpiece inconspicuous and suppresses the occurrence of insufficient filter hardness.

FIG. 1 is a longitudinal sectional view of a cigarette according to the first embodiment. FIG. 2 is a perspective view of the cigarette according to the first embodiment. FIG. 3 is a diagram illustrating the center hole filter manufacturing apparatus according to the first embodiment. FIG. 4 is a longitudinal sectional view of a filter according to a comparative example. FIG. 5 is a diagram conceptually showing tar dirt on the mouth end face of the filter according to the comparative example. FIG. 6 is a diagram for explaining another variation of the positions where the air holes are arranged in the filter according to the first embodiment. FIG. 7 is a longitudinal sectional view of a cigarette according to the first modification. FIG. 8 is a longitudinal sectional view of a cigarette according to the second modification. FIG. 9 is a longitudinal sectional view of a cigarette according to the third modification.

Hereinafter, embodiments of a cigarette with a filter according to the present invention will be described in detail with reference to the drawings. The dimensions, materials, shapes, relative arrangements, and the like of the constituent elements described in the present embodiment are not intended to limit the technical scope of the invention only to those unless otherwise specified.

<Embodiment 1>
FIG. 1 is a longitudinal sectional view of a cigarette 1 according to the first embodiment. FIG. 2 is a perspective view of the cigarette 1 according to the first embodiment. The cigarette 1 is a cigarette with a filter including a cigarette rod 2 and a filter 4 connected to one end of the cigarette rod 2 via a chip paper 3.

The tobacco rod 2 is formed by winding the tobacco stamp 21 with a wrapping paper 22 into a cylindrical shape (bar shape), and is also referred to as a “single roll”. The filter 4 is a member for filtering smoke components contained in the mainstream smoke when passing the mainstream smoke generated when the cigarette 1 is smoked, and is a circle having substantially the same diameter as the tobacco rod 2. It is shaped like a column.

The filter 4 is wound by the chip paper 3 and is connected to the rear end side of the tobacco rod 2 through the chip paper 3. The chip paper 3 connects (links) the end portion of the tobacco rod 2 and the filter 4 by winding them together. Hereinafter, in the longitudinal direction (axial direction) of the tobacco rod 2, the end connected to the filter 4 is referred to as “rear end”, and the opposite end is referred to as “front end” (front end). In the longitudinal direction (axial direction) of the filter 4, the end connected to the tobacco rod 2 is referred to as “front end”, and the end opposite to the front end is referred to as “mouth end”. In addition, a cross section along the longitudinal direction (axial direction) of the cigarette 1 (cigarette rod 2 and filter 4) is defined as a “longitudinal section”, and a cross section in a direction orthogonal thereto is defined as a “cross section”. Moreover, the code | symbol CL shown in FIG. 1 shows the central axis of the cigarette 1 (cigarette rod 2, filter 4).

In the filter 4, a filtration section S1, a front section S2, and a suction end section S3 are arranged in this order from the front end side. The filtration section S1 is provided with a filter material 41 obtained by winding a fiber bundle of cellulose acetate formed into a cylindrical shape with a winding paper. However, the filter medium 41 in the present embodiment is not limited to a fiber bundle of cellulose acetate, and various materials can be adopted.

Center hole filters 42 and 43, each of which is formed by winding a cellulose acetate fiber bundle, which is formed in a columnar shape and has a through passage along the axial direction, are disposed in the front section S2 and the suction end section S3. Has been. Hereinafter, the through passage formed in the center hole filter 42 in the front section S2 is referred to as a “first center hole 42a”. Further, the through passage formed in the center hole filter 43 in the mouth end section S3 is referred to as a “second center hole 43a”.

The first center hole 42a passes through the center of the center hole filter 42 and penetrates along the axial direction. On the other hand, the second center hole 43a passes through the center of the center hole filter 43 along the axial direction. The first center hole 42a and the second center hole 43a are smoke flow paths (passages) for flowing (passing) mainstream smoke. In this embodiment, the 1st center hole 42a and the 2nd center hole 43a are arrange | positioned coaxially, and the cross-sectional area of the 2nd center hole 43a is larger than the cross-sectional area of the 1st center hole 42a. In other words, the cross-sectional area of the through passage in the suction end section S3 is set larger than the cross-sectional area of the through passage in the front section S2. Further, the length of the suction end section S3 (center hole filter 43) in the filter 4 is shorter than the length of the preceding section S2 (center hole filter 42). In addition, in this embodiment, although the cross-sectional shape of the 1st center hole 42a and the 2nd center hole 43a is circular shape, it is not restricted to this.

In the chip paper 3 around which the filter 4 is wound, a ventilation hole 31 for diluting mainstream smoke by introducing ventilation air (outside air) into the filter 4 is formed. The ventilation hole 31 is arrange | positioned in the position corresponding to the filtration section S1 in the filter 4 as shown in FIG. At the time of smoking, external air flows into the filter 4 through the vent hole 31, and mainstream smoke is diluted by mixing the mainstream smoke flowing into the filter 4 from the tobacco rod 2 side with the air introduced from the vent hole 31. The

Next, an example of a method for manufacturing the center hole filters 42 and 43 will be described. The center hole filters 42 and 43 can be manufactured by various known methods. FIG. 3 is a diagram showing a center hole filter manufacturing apparatus 100. The manufacturing apparatus 100 includes a storage container 110 that stores filter fibers (for example, acetate tow) 150, a plasticizer addition unit 120, a molding apparatus 130, a wrapping apparatus 140, and the like. The filter fibers 150 stored in the storage container 110 are fed out along a predetermined feeding path. In this feeding process, the filter fiber 150 is spread to be formed into a sheet by undergoing a fiber opening process. Thereafter, the sheet-like filter fiber 150 is subjected to the addition of a plasticizer such as triacetin by the plasticizer addition unit 120 and is supplied to the subsequent molding apparatus 130.

The forming device 130 is a forming device for forming the sheet-like filter fiber 150 into a hollow rod-shaped filter continuum, and allows the sheet-like filter fiber 150 to pass through while being squeezed into the hollow rod-shaped filter continuum. A mandrel (not shown) which is a tubular forming path to be formed is provided. The sheet-like filter fibers 150 supplied to the forming apparatus 130 are formed into a rod shape around the mandrel, and are sequentially drawn out, and are pulled out from the mandrel to form a center hole. The filter continuum having the center hole formed in this way is supplied to the subsequent lapping device 140. The filter continuum supplied to the wrapping device 140 becomes a filter rod by being wound by a web, and the center hole filters 42 and 43 can be manufactured by cutting the filter rod into a predetermined length.

Next, the operation and effect of the cigarette 1 in this embodiment will be described. When the cigarette 1 smokes, the mainstream smoke generated by the tobacco rod 2 flows into the filter 4, and the mainstream smoke is filtered through components such as tar and nicotine when passing through the filter medium 41 in the filtration section S1. . Since CO contained in the mainstream smoke is a gas phase component, it is not filtered by the filter medium 41. The filter section S1 of the filter 4 is provided with a vent hole 31 drilled in the chip paper, so that air introduced through the vent hole 31 is mixed with mainstream smoke passing through the filter section S1. Thereby, the components in the smoke of the mainstream smoke are diluted, and tar, nicotine, CO, etc. contained in the mainstream smoke are reduced.

By the way, the filter 4 in the present embodiment is designed to have a low filtration and high dilution so that the balance between the dilution with the air introduced from the vent hole 31 and the filtration with the filter medium 41 is a so-called low filtration and high dilution. More specifically, low filtration and high dilution can be realized by arranging a front section S2 and a suction end section S3, which are sections having no function of filtering mainstream smoke, in a part of the filter 4. Yes.

Here, center hole filters 42 and 43 each having a hollow first center hole 42a and a second center hole 43a are provided in the front section S2 and the mouth end section S3. Of the cross section of the center hole filter 42, the region excluding the hollow first center hole 42a is occupied by a compression-molded fiber bundle. Therefore, in the cross section of the center hole filter 42, it can be said that the ventilation resistance in the region occupied by the fiber bundle is extremely larger than the ventilation resistance of the first center hole 42a. Similarly, in the cross section of the center hole filter 43, the region excluding the hollow second center hole 43a is occupied by a compression-molded fiber bundle. Therefore, in the cross section of the center hole filter 43, it can be said that the ventilation resistance in the region occupied by the fiber bundle is extremely larger than the ventilation resistance of the second center hole 43a. Therefore, the mainstream smoke that has passed through the filtration section S1 sequentially flows through the first center hole 42a and the second center hole 43a having extremely small ventilation resistance, and is finally sucked into the oral cavity from the mouth end. As described above, the filter 4 in the present embodiment has a filtering function of filtering the smoke component of the mainstream smoke only in the filtering section S1, and the subsequent front section S2 and the suction end section S3 have a filtering function of the smoke component. I don't have it. As a result, the balance between mainstream smoke dilution and filtration is low filtration and high dilution, and the CO ratio to tar can be reduced. As a result, the sensation of cigarette 1 can be increased, and the flavor can be improved.

Furthermore, the cigarette 1 in the present embodiment is more effective than the cross-sectional area of the first center hole 42a in the front section S2 from the viewpoint of suppressing tar from locally adhering to the suction mouth end face of the filter 4 during smoking. The size relationship between the cross-sectional areas of the two through passages is defined so that the cross-sectional area with the second center hole 43a in the mouth end section S3 is increased. Hereinafter, the filter 4 according to the present embodiment will be described with reference to the comparative examples shown in FIGS. 4 and 5.

FIG. 4 is a longitudinal sectional view of a filter 40 according to a comparative example. In the filter 40, a filter medium 410 and a center hole filter 430 are connected from the front end side. The filter medium 410 and the center hole filter 430 of the filter 40 are substantially equal to the filter medium 41 and the center hole filter 43 of the filter 4 of the present embodiment. That is, the filter 40 according to the comparative example is substantially equivalent to a configuration in which the preceding section S2 (center hole filter 42) is removed from the filter 4 illustrated in FIG.

When smoking a cigarette provided with the filter 40 according to the comparative example, mainstream smoke flowing into the filter 40 from the tobacco rod side sequentially flows through the filter medium 410 and the center hole 430a of the center hole filter 430 and is sucked into the oral cavity. . FIG. 5 is a diagram conceptually showing local tar contamination on the end face of the mouthpiece of the filter 40 according to the comparative example. When the cigarette according to the comparative example is smoked, tar tends to locally adhere to the periphery (edge) of the center hole 430a on the end surface of the mouthpiece, and tar dirt on the end surface of the mouth end becomes easily noticeable.

On the other hand, the filter 4 in the present embodiment is configured such that the cross-sectional area of the second center hole 43a in the mouth end section S3 is equal to the section of the first center hole 42a in the front section S2 provided immediately upstream of the mouth end section S3. By setting it larger than the area, it is possible to make the local tar stain around the second center hole 43a (edge) on the end face of the mouthpiece less noticeable.

That is, as shown in FIG. 1, the filter 4 according to the present embodiment has a mainstream smoke cross-sectional area at the boundary position between the front section S2 and the suction end section S3, which is a position deeper from the suction end face. Increase (first center hole 42a → second center hole 43a). Then, when flowing from the first center hole 42a into the second center hole 43a at the boundary position between the front section S2 and the mouth end section S3, the mainstream smoke flows into the second center hole 43a while spreading in the cross-sectional direction. Therefore, on the rear end face of the center hole filter 42, local tar adhesion can occur around the first center hole 42a (edge). However, as shown in FIG. 1, the rear end face of the center hole filter 42 is disposed at a position deeper from the end face of the mouth end by the length of the end section S3. Therefore, even if a local tar adhesion occurs around the first center hole 42a on the rear end face of the center hole filter 42, there is an advantage that the tar dirt is not easily seen by the smoker.

Next, the difference in flow velocity (flow rate) of the mainstream smoke flowing through the center side and the outer peripheral side of the second center hole 43a will be described. Since the cross-sectional area of the second center hole 43a is larger than that of the first center hole 42a, the center side of the second center hole 43a overlaps the first center hole 42a in the axial direction, but the outer peripheral side is the first center hole 42a. And do not overlap in the axial direction. As a result, the flow velocity (flow rate) of the mainstream smoke is relatively slow (decreased) in the outer peripheral region compared to the center side in the second center hole 43a. Thus, the mainstream smoke sucked into the oral cavity from the rear end of the second center hole 43a comes into contact with the mouth end face by reducing the flow velocity (flow rate) of the mainstream smoke flowing on the outer peripheral side in the second center hole 43a. The frequency of doing can be reduced. Therefore, local tar adhesion to the periphery (edge) of the second center hole 43a on the end surface of the mouthpiece can be made difficult to occur. As a result, tar dirt on the end face of the mouthpiece in the filter 4 can be suppressed, making it less noticeable.

Furthermore, according to this embodiment, low filtration and high dilution of the filter 4 can be realized without providing a section such as a cavity or a recess in which the entire cross section of the filter 4 is hollow (cavity). According to this, it is possible to suppress insufficient hardness over the entire section in the longitudinal direction of the filter 4. Therefore, it is possible to prevent the inconvenience that the filter 4 is inadvertently deformed before or during smoking. As described above, according to the cigarette 1 of the present embodiment, tar dirt on the mouth end face of the filter 4 can be made inconspicuous, and insufficient hardness of the filter 4 can be suitably suppressed.

Furthermore, in the filter 4 of the present embodiment, the length of the suction end section S3 is set to be shorter than the length of the preceding section S2. Here, since the thickness (wall thickness) of the center hole filter 43 is thinner than the thickness (wall thickness) of the center hole filter 42, the length of the center hole filter 43 is made shorter than the length of the preceding section S2. Thereby, it becomes possible to more reliably suppress the lack of hardness of the filter 4 from becoming obvious.

Further, in the present embodiment, the first center hole 42a and the second center hole 43a in the filter 4 are arranged coaxially. By comprising in this way, the frequency which the mainstream smoke which flows out out of the 2nd center hole 43a in a suction mouth end surface contacts a suction mouth end surface can be reduced more uniformly over the perimeter of the 2nd center hole 43a. As a result, tar dirt on the end face of the mouthpiece of the filter 4 can be made less conspicuous.

Further, in the present embodiment, since the filtering material 41 is provided in the filtering section S1 located at the front end portion of the filter 4, the tobacco engraving 21 of the tobacco rod 2 enters the filter 4 through the filtering material 41. It can function as a spillage suppression means that suppresses (spilling). That is, the filtering material 41 of the filtering section S1 also serves as a spillage suppressing means. The squeezing suppression means is not limited to the filter medium 41 as long as it has a function of suppressing the tobacco squeezing 21 from entering the filter 4. For example, various configurations such as a mesh material made of metal or resin can be used as the spillage suppressing means. However, the material cost of the filter 4 can be reduced and the manufacturing process can be prevented from becoming complicated by making the filter medium 4 also serve as a spillage suppressing means as in this embodiment.

Furthermore, in this embodiment, the vent hole 31 in the filter 4 is arranged at a position corresponding to the filtration section S1. By adopting such a configuration, there is an advantage that ventilation air can be smoothly introduced from the vent hole 31 into the filter 4. A vent hole 31 is disposed in the filtration section S1. And by arrange | positioning the ventilation hole 31 upstream from the suction end section S3 like this embodiment, by the flow of the air for ventilation (dilution) introduced in the filter 4 from the ventilation hole 31, The mainstream smoke flowing through the first center hole 42a of the front section S2 is easily moved toward the center side of the first center hole 42a. That is, the flow of air flowing in from the vent hole 31 is brought closer to the outer periphery of the first center hole 42a, and the mainstream smoke is made to flow toward the downstream side while being brought closer to the center of the first center hole 42a. it can. Since the flow of mainstream smoke and dilution air is maintained even when passing through the second center hole 43a of the mouth end section S3, the mainstream is sucked into the oral cavity from the rear end of the second center hole 43a. The effect of reducing the frequency of smoke coming into contact with the end face of the mouthpiece is further enhanced. Therefore, tar dirt on the end face of the mouth of the filter 4 can be made even more inconspicuous. The action of “passing mainstream smoke toward the center side of the first center hole 42 a” described above can be obtained by arranging the vent hole 31 on the upstream side of the suction end section S3 in the filter 4.

Therefore, instead of arranging the vent hole 31 at a position corresponding to the filtration section S1, it is also preferable to arrange the vent hole 31 at a position corresponding to the preceding section S2 as in the configuration example shown in FIG. FIG. 6 is a diagram for explaining another variation of the position where the vent hole 31 is arranged. In the example shown in FIG. 6, the vent hole 31 is disposed at a position corresponding to the front section S <b> 2 of the filter 4. As illustrated, the vent hole 31 penetrates not only the chip paper 3 but also the side wall surrounding the second center hole 43 a of the center hole filter 42. Then, as in the case where the vent hole 31 is arranged in the filtration section S1, the mainstream smoke is removed from the center hole by the flow of dilution air introduced from the vent hole 31 of the front section S2 into the second center hole 43a of the center hole filter 42. It can be made to flow toward the center side of 42a, and tar dirt on the end face of the mouth of the filter 4 can be made inconspicuous. In the configuration example shown in FIG. 6, the vent hole 31 is opened in both the side wall of the center hole filter 42 and the chip paper 3, but even if the vent hole 31 is opened only in the chip paper 3. Even in that case, the air that has passed through the center hole filter 42 can be introduced into the second center hole 43a.

Next, the diameter and length of the first center hole 42a and the second center hole 43a in the filter 4 will be described as an example. In this embodiment, the aspect which makes the diameter of the 1st center hole 42a in front | former section S2 (center hole filter 42) the range of 26% or more and 39% or less of the diameter in the filter 4 is mentioned as an example. For example, when the diameter of the filter 4 is a normal size of 7.7 mm, an embodiment in which the diameter of the first center hole 42 a is 2 mm or more and 3 mm or less can be exemplified. Moreover, when the diameter of the filter 4 is a slim size of 5.3 mm, an embodiment in which the diameter of the first center hole 42 a is 1.3 mm or more and 2 mm or less can be exemplified.

On the other hand, a mode in which the diameter of the second center hole 43a of the mouth end section S3 (center hole filter 43) is set to be in the range of more than 39% and not more than 78% of the diameter of the filter 4 is an example. For example, when the diameter of the filter 4 is a normal size of 7.7 mm, an embodiment in which the diameter of the second center hole 43a is larger than 3 mm and not larger than 6 mm can be cited. For example, when the filter 4 has a slim size of 5.3 mm, the second center hole 43a may have a diameter greater than 2 mm and not greater than 4.1 mm.

Moreover, the aspect which makes the length of the front | former stage section S2 in which the center hole filter 42 is arrange | positioned 7 mm or more is mentioned, The aspect in which the length of the suction end section S3 in which the center hole filter 43 is arrange | positioned is 5 mm or more and 10 mm or less Is mentioned. Moreover, the aspect (diameter / length) of the diameter with respect to the length of the 2nd center hole 43a in mouth end section S3 can set the aspect which is 0.3 or more and 1.2 or less. From the viewpoint of making it difficult to visually recognize local tar dirt on the rear end surface of the front section S2 (center hole filter 42), the ratio of the diameter to the length of the second center hole 43a is preferably 1.2 or less.

In addition, the cross-sectional shape of the first center hole 42a in the front section S2 and the second center hole 43a in the mouth end section S3 is not limited to a circular shape, and various shapes can be adopted. Here, when the cross-sectional shape of the first center hole 42a is not circular, the first center hole 42a may be formed so that the circumscribed circle of the first center hole 42a has a diameter of 2 mm or more and 3 mm or less. it can. Moreover, when the cross-sectional shape of the second center hole 43a is not circular, an embodiment in which the second center hole 43a is formed so that the diameter of the inscribed circle of the second center hole 43a is greater than 3 mm and equal to or less than 6 mm. Can do.

<Modification>
Various modifications can be employed for the filter 4 according to the present embodiment. Hereinafter, modified examples of the filter 4 in the present embodiment will be described.

FIG. 7 is a longitudinal sectional view of a cigarette 1A according to the first modification. The filter 4A provided in the cigarette 1A is common to the filter 4 shown in FIG. 1 except that the charcoal filtration section S0 including the charcoal (activated carbon) -added filter material 44 is disposed in the front stage of the filtration section S1. . From the front end side of the filter 4A, a charcoal filtration section S0, a filtration section S1, a front section S2, and a suction end section S3 are arranged in this order. The charcoal-added filter material 44 provided in the charcoal filtration section S0 is a charcoal filter in which a cellulose acetate fiber bundle to which activated carbon (for example, 20 to 80 mesh coconut-derived charcoal) is added is wound with a wrapping paper. Charcoal (activated carbon) functions as an adsorbent that adsorbs smoke components of mainstream smoke.

In this modification, a filter medium 41 made of cellulose acetate fiber is connected to the rear end of the charcoal-added filter medium 44. According to this, the activated carbon added to the charcoal-added filter material 44 enters the first center hole 42a of the front-stage section S2 (center hole filter 42) in the filter medium 41 arranged at the rear stage of the charcoal-added filter medium 44. It can be made to function as an activated carbon spillage suppression means that suppresses. Instead of installing the filter medium 41 at the rear end of the charcoal filtration section S0, a metal or resin mesh material that functions as activated carbon spillage suppression means may be disposed.

Moreover, in the filter 4 shown in FIG. 1, although the example which arrange | positions the front | former section S2 and the suction end section S3 as a section without a filtration function is disclosed, it filters between the filtration section S1 and the front | former section S2. A section having no function or a section having a filtering function may be appropriately disposed. In other words, the filter 4 in the present embodiment has a cross-sectional area of the second center hole 43a, which is a through path of the suction end section S3, as a through path of the front section S2 located immediately upstream of the suction end section S3. It suffices if it is set larger than the cross-sectional area of one center hole 42a, and various modifications can be adopted for the configuration upstream of the preceding section S2 in the filter 4.

FIG. 8 is a longitudinal sectional view of a cigarette 1B according to the second modification. The filter 4B provided in the cigarette 1B according to the modified example 2 employs a structure in which center hole sections S4 and S5 are additionally arranged between the filtration section S1 and the front section S2 in the filter 4 shown in FIG. A center hole filter 45 having a third center hole 45a is disposed in the center hole section S4, and a center hole filter 46 having a fourth center hole 46a is disposed in the center hole section S5. In the filter 4B shown in FIG. 8, the third center hole 45a, the fourth center hole 46a, the first center hole 42a, and the second center hole 43a are coaxially arranged. In addition, the flow passage cross-sectional area of the mainstream smoke in each center hole increases stepwise in the order of the third center hole 45a, the fourth center hole 46a, the first center hole 42a, and the second center hole 43a. Also in such a modification, it is possible to make the same effect as the filter 4 shown in FIG. 1, that is, tar dirt on the mouth end face of the filter less noticeable and to suppress the hardness of the filter from being insufficient.

FIG. 9 is a longitudinal sectional view of a cigarette 1C according to Modification 3. In the filter 4C included in the cigarette 1C according to the modification 3, the positions of the center hole sections S4 and S5 in the filter 4B illustrated in FIG. 8 are switched. That is, in the filter 4C, the filtration section S1, the center hole section S5, the center hole section S4, the front section S2, and the suction end section S3 are arranged in this order from the front end side. In the filter 4C according to the modified example 3, the mainstream smoke that has passed through the filtration section S1 flows into the fourth center hole 46a, and sequentially passes through the third center hole 45a, the first center hole 42a, and the second center hole 43a. And then sucked into the smoker. Also in this modified example, the cross-sectional area of the second center hole 43a in the mouth end section S3 is larger than the cross-sectional area of the first center hole 42a in the preceding section S2 provided immediately upstream of the mouth end section S3. Since it is set large, it becomes possible to make tar dirt on the end face of the mouth of the filter inconspicuous, and to suppress insufficient hardness of the filter, as with the filter 4 shown in FIG.

The preferred embodiments of the present invention have been described above, but the filter-attached cigarette according to the embodiments can be variously changed, improved, combined, and the like.

DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C ... Cigarette 2 ... Cigarette rod 3 ... Chip paper 4, 4A, 4B, 4C ... Filter S1 ... Filtration section S2 ... Preceding section S3 ... Mouth end section 41 ... filtering material 42, 43 ... center hole filter 42a ... first center hole 43a ... second center hole

Claims (6)

A cigarette with a filter comprising: a tobacco rod including a tobacco engraver; and a filter connected to an end of the tobacco rod via a tip paper,
The filter is
A mouth end section disposed at the mouth end, wherein the mouth end section is provided with a fiber bundle in which a through passage for flowing mainstream smoke is formed along the axial direction;
A front section connected to the front end of the mouth end section, a front section provided with a fiber bundle in which a through passage for flowing mainstream smoke is formed along the axial direction;
Have
A cigarette with a filter, wherein a cross-sectional area of the through-passage in the mouth end section is larger than a cross-sectional area of the through-passage in the preceding section. 2. The cigarette with a filter according to claim 1, wherein a length of the mouth end section is shorter than a length of the front section. The cigarette with a filter according to claim 1 or 2, wherein each through-passage in the mouth end section and the front section is coaxially arranged. The filter according to any one of claims 1 to 3, wherein a spillage suppressing means is provided at a front end portion of the filter to prevent the cigarette stamp from entering the filter. cigarette. The filter according to claim 4, wherein a filter medium including a fiber bundle for filtering mainstream smoke is disposed at a front end portion of the filter, and the filter medium also serves as the spillage suppressing means. cigarette. The chip paper has a vent hole for introducing outside air into the filter to dilute mainstream smoke,
The cigarette with a filter according to any one of claims 1 to 5, wherein the vent hole is disposed on an upstream side of the suction end section in the filter.

Images