Methods for inspecting strip-shaped products

Abstract

The present invention relates to a method for inspecting a strip-shaped article, the method comprising: - providing a first roller having a plurality of seats; - providing a sensing sensor including a coil for at least one of the plurality of seats of the first roller; - providing a strip-shaped article including a first sensor for at least one of the plurality of seats of the first roller, the first sensor comprising a conductive material; - inserting the strip-shaped article into the coil of the sensing sensor; - detecting a maximum or minimum value of a parameter function of the impedance of the coil during insertion of the strip-shaped article; - discarding the strip-shaped article based on the maximum or minimum value of the parameter function of the impedance.

Description

Technical Field

[0001] This invention relates to a method for inspecting components of strip-shaped articles, preferably aerosol-generating articles. The inspection according to the method is performed by means of a sensing sensor. Background Technology

[0002] Aerosol generating apparatuses, including an aerosol forming matrix and an induction heating device, are known. The induction heating device includes an induction source that generates an alternating electromagnetic field, which induces eddy currents and hysteresis losses in a sensor. The sensor is in thermal proximity to the aerosol forming matrix, such as a tobacco matrix. The heated sensor then heats the aerosol forming matrix, which comprises a material capable of releasing volatile compounds that can form aerosols.

[0003] In some components, the receptor is located inside the component of the aerosol-generating article. Summary of the Invention

[0004] Due to manufacturing tolerances, it is possible for the receptors in a component to be out of the desired position or not properly oriented. If the receptors are held in the wrong position or orientation, product consistency may be lacking in terms of aerosol delivery when the component is used in an aerosol generation device.

[0005] Therefore, it is desirable to detect such defects as early as possible to ensure that only compatible products are produced and to avoid unnecessary costs and waste.

[0006] Furthermore, components, including those containing sensors, are processed at high speeds, such as 5,000 components per minute. Therefore, the time window for inspecting such components to determine if they meet production requirements is relatively short. For example, when components are positioned in the rollers of the combiner, the components rotate at high speeds, and the time window for sensors to capture the data needed to assess the shape, position, or presence or absence of sensors is approximately 200 milliseconds.

[0007] Therefore, it is desirable to detect defects related to the receptors at a relatively high speed.

[0008] According to one aspect, the present invention relates to a method of inspecting strip articles, the method comprising: providing a first drum having a plurality of seats. Preferably, the method comprises: providing an inductive sensor including a coil for at least one of the plurality of seats of the first drum. Preferably, the method comprises providing a strip article including a first receptor comprising a conductive material for at least one of the plurality of seats of the first drum. Preferably, the method comprises inserting the strip article into the coil of the inductive sensor. Preferably, the method comprises detecting a maximum or minimum value of a parametric function of the impedance of the coil during insertion of the strip article. Preferably, the method comprises discarding the strip article based on the maximum or minimum value of the parametric function of the impedance.

[0009] The method of the present invention comprises providing a first drum. The first drum defines a drum rotation axis and the first drum is adapted to rotate about the drum rotation axis. For example, the first drum may be mechanically driven by a drum drive including gears or a toothed belt. The first drum may be driven by an electric drum drive. The first drum is preferably cylindrical. The first drum preferably includes an outer surface. The outer surface is, for example, a substantially cylindrical surface having the drum rotation axis as a geometric center.

[0010] The first drum is adapted to convey strip articles about its rotation axis and to rotate the strip articles. Preferably, the first drum is adapted to convey a plurality of strip articles and to rotate a plurality of strip articles. Preferably, the first drum is adapted to convey N strip articles and to rotate N strip articles, where 5 < N < 100, more preferably 20 < N < 50.

[0011] The first drum includes at least one seat preferably formed on the outer surface of the drum. The first drum is preferably adapted to hold the strip article in the seat during conveyance. For example, the first drum is adapted to hold the strip article in the seat while the first drum rotates about its rotation axis. The seat preferably extends longitudinally along a seat axis. The seat is adapted to receive the strip article when the first drum rotates. Preferably, the strip article is placed in the seat with its longitudinal axis parallel to the seat axis. Preferably, each seat is configured such that the strip article can be received in each seat when the seat axis and the longitudinal axis of the strip article are parallel. More preferably, the seat axis and the longitudinal axis of the strip article are aligned. The seat is preferably adapted to accommodate a single strip article.

[0012] Preferably, the axis of the seat portion is parallel to the axis of rotation of the first drum. Thus, when the strip article is positioned in the seat portion, the longitudinal axis of the strip article is preferably parallel to the axis of rotation of the first drum.

[0013] Preferably, the first drum includes N seat portions, where 5 < N < 100, more preferably 20 < N < 50. Preferably, all the seat portions are formed on the circumferential surface of the first drum. More preferably, the seat portions are equally spaced around the outer surface of the first drum. In some embodiments, the first drum includes 40 seat portions.

[0014] Preferably, all the seat portions present in the first drum have the same geometry. For example, each seat portion includes a receiving surface adapted to contact the outer surface of the strip article. Preferably, the receiving surface includes a part of a concave surface (such as a cylindrical surface). The receiving surface is a part of the outer surface of the first drum. The receiving surface may be a part of a cylindrical surface having a diameter equal to or slightly larger than the diameter of the strip article conveyed by the first drum. The axis of the receiving surface defines the axis of the seat portion.

[0015] Preferably, the axis of the seat portion is parallel to the axis of rotation of the first drum, so that when the strip article is positioned in the seat portion of the first drum, its longitudinal axis is parallel to the axis of rotation of the first drum.

[0016] Preferably, the first drum further includes a first side surface and a second side surface located at two opposite sides of the outer surface. Preferably, the seat portion extends from the first side surface to the opposite second side surface. The seat portion may reach the first side surface or the second side surface or both, such that the seat portion is "open" at both ends. Alternatively, the seat portion ends do not reach the first side surface or the second side surface, and in this case, the seat portion is a "closed" seat portion.

[0017] Preferably, each seat portion includes a suction orifice connected to a suction system or a pneumatic system, and the suction orifice is adapted to hold the strip article in the seat portion by suction when the drum rotates. Depending on, for example, the size and weight of the strip article, there may be more than one suction orifice.

[0018] According to the present invention, a strip article is provided into the seat portion of the first drum. Preferably, the strip article is provided in a plurality of seat portions of the first drum. Preferably, the strip article defines a longitudinal axis. Preferably, the strip article defines a first end and a second end.

[0019] Preferably, the cross-section of the strip-shaped article along a plane perpendicular to its longitudinal axis is circular or elliptical. However, the strip-shaped article may also have a rectangular or polygonal cross-section. The strip-shaped article includes an outer surface (preferably generally cylindrical) extending along the longitudinal axis. In the case of a generally cylindrical strip-shaped article, the longitudinal axis corresponds to the axis of a cylinder.

[0020] Preferably, the strip-shaped article comprises an aerosol-generating article, a component of an aerosol-generating article, or one or more components of an aerosol-generating article. The component of the aerosol-generating article may include an aerosol-forming matrix. The aerosol-forming matrix may include homogenized tobacco material.

[0021] The strip-shaped article further includes a first receptor. The first receptor is preferably in thermal contact with the aerosol forming matrix. Thermal contact is established to heat the aerosol forming matrix. Upon heating, the aerosol forming matrix releases aerosols. Preferably, the first receptor is surrounded by the aerosol forming matrix. Preferably, the first receptor is completely inserted into a component of the strip-shaped article, i.e., the first receptor is not visible from the outside of the strip-shaped article. Preferably, the first receptor is surrounded by the aerosol forming matrix in all directions.

[0022] Preferably, the first receptor is closer to the first end of the strip-shaped article than to the second end. Given a plane perpendicular to the longitudinal axis and dividing the strip-shaped article into a first half including the first end and a second half including the second end, preferably, the first receptor is primarily located in the first half. Preferably, the first receptor is located at or near the first end of the strip-shaped article. Preferably, the first receptor is fully inserted into a component of the strip-shaped article. Preferably, the first receptor extends from the first end of a component of the strip-shaped article to the second end. Preferably, the first receptor defines a longitudinal axis. Preferably, the first receptor is inserted into the strip-shaped article such that the longitudinal axis of the first receptor is parallel to the longitudinal axis of the strip-shaped article. Preferably, the longitudinal axis of the first receptor is parallel to or forms an angle of less than 20 degrees with the longitudinal axis of the strip-shaped article. More preferably, the longitudinal axis of the first receptor and the longitudinal axis of the strip-shaped article are aligned.

[0023] The longitudinal axis of the first receptor can be the axis of symmetry of the first receptor.

[0024] The first receptor is made of a conductive material. Preferably, the first receptor is made of a metal. Preferably, the first receptor is made of a ferromagnetic material. Although the first receptor is made of a conductive material, it can be covered by other materials, such as a solid (e.g., a layer of a different material) or a liquid (e.g., a gel).

[0025] Preferably, the first receptor has a strip shape. Preferably, the thickness of the first receptor is between 30 micrometers and 60 micrometers. Preferably, the length of the first receptor is between 5 millimeters and 20 millimeters.

[0026] Preferably, the strip-shaped product is wrapped in a wrapping sheet.

[0027] At least one seat of the roller is associated with an inductive sensor. More preferably, multiple seats of the roller, and even more preferably all seats of the roller, are associated with an inductive sensor. In the technical field, inductive sensor and induction sensor are synonyms. An inductive sensor uses an electric current induced by a magnetic field to detect nearby conductive objects, such as metallic objects. The inductive sensor includes a coil as a sensor to generate a magnetic field, such as a high-frequency magnetic field. If a conductive object, such as a first sensor embedded in the strip, is present near the changing magnetic field, a current will flow in the conductive object. This resulting current in the conductive object forms a new magnetic field that is opposite to the original magnetic field formed by the current flowing in the coil. The net effect is that the new magnetic field changes the impedance, such as resistance, of the system "coil and first sensor" in the inductive sensor. By measuring the impedance, the sensor can determine when conductive material has been brought into the vicinity of the inductive sensor. The change in impedance depends on the type of conductive material constituting the object, the distance between the object and the sensor, and the size and shape of the object.

[0028] The sensing sensor can be, for example, a Texas Instruments integrated circuit LCD 1101. Preferably, the sensing sensor measures the resistance equivalent to the first sensor. The sensing sensor can measure the impedance and resonant frequency of the equivalent system "coil and first sensor" by adjusting the oscillation amplitude at a constant level in a closed-loop configuration while monitoring the energy dissipated by the resonator. By monitoring the amount of power injected into the resonator, the sensing sensor can determine the equivalent parallel resistance of the resonator, which it returns as a digital value.

[0029] Therefore, the sensing sensors are associated with the seats of the roller, preferably multiple sensing sensors are associated with multiple seats of the roller (one sensor per seat), to detect parameters that are functions of the impedance of the coil. Preferably, the parameters are detected as functions of the system "coil and first sensor".

[0030] The impedance parameter function is preferably the impedance Z of the coil itself, or the equivalent resistance of the coil, or the inductance of the coil.

[0031] The sensing sensor includes a coil defining an internal volume. This internal volume is defined by the windings of the coil. For example, the sensing sensor includes a cylindrical coil comprising multiple windings of wire. Preferably, the coil does not include a core; that is, the internal volume comprises air. Preferably, the internal volume of the coil is large enough that the strip-shaped article can be at least partially inserted into the coil. The total length of the coil is preferably longer than the length of the first sensor. The length of the first sensor, when measured, refers to its nominal length. For proper insertion, the inner diameter of the coil is preferably wider than the diameter of the strip-shaped article. Preferably, the coil defines a longitudinal axis, hereinafter referred to as the coil axis.

[0032] Preferably, the strip is inserted into the coil of the sensing sensor. Insertion can be complete, meaning the entire strip is contained within the internal volume of the coil, or it can be partial, meaning only a portion of the strip is contained within the internal volume of the coil. However, preferably, the strip is inserted into the coil such that the entire first sensor is located within the internal volume of the coil during insertion.

[0033] Preferably, the coil of the sensing sensor is mounted at the seat of the first roller with the coil axis and the seat axis parallel to each other. This also preferably means that the coil axis and the longitudinal axis of the strip (when present in the seat) are also parallel.

[0034] The inductive sensor is used to measure a parametric function of the coil's impedance, which is modified by the presence of the first sensor within the strip. For this purpose, the inspection device preferably includes a control unit. The control unit is electrically connected to the inductive sensor. The control unit interprets the signal from the inductive sensor to evaluate the parametric function of the impedance, such as the impedance itself. The control unit can be part of the inductive sensor. The control unit can also be adapted to calculate the maximum or minimum value of the parametric function of the impedance, as detailed below.

[0035] In order to insert the strip-shaped product into the sensing sensor, relative movement occurs between the strip-shaped product and the sensing sensor.

[0036] Preferably, the insertion of the strip into the coil is made from the first end of the strip. The first receptor is preferably closer to the first end than the second end, therefore, insertion from the first end requires a shorter coil to fully insert the receptor into the internal volume of the coil compared to insertion from the second end. In this way, only a limited portion of the strip needs to enter the coil to study the characteristics of the first receptor.

[0037] Preferably, the movement of inserting the strip into the coil is a linear movement in a direction parallel to the axis of the coil. Preferably, the movement is a linear movement parallel to the axis of the seat. The movement can be a movement of the strip toward the coil (and the coil is stationary), a movement of the coil toward the strip (and the strip is stationary), or a movement of both the coil and the strip toward each other. It should be understood that when saying the element is stationary, reference is made to the outer surface of the roller. Therefore, the coil or the strip can be stationary relative to the outer surface of the roller. The outer surface itself rotates during the inspection of the strip.

[0038] The movement of the coil, or the strip, or both, can be performed in many different ways. For example, the coil includes a first half-coil and a second half-coil. The first half-coil and the second half-coil are two portions of the coil cut along a plane parallel to the longitudinal axis of the coil. Therefore, the first half-coil and the second half-coil can have different sizes. More preferably, when cut along a plane containing the longitudinal axis of the coil, the first half-coil and the second half-coil are each half of the coil. Each half-coil includes multiple half-windings. Each half-winding is, for example, an arc of a circumference, more preferably half a circumference. The arc of the circumference of the first half-coil and the corresponding arc of the circumference of the second half-coil form the winding of the coil. The first half-coil and the second half-coil can move relative to each other. The movement performed by the first half-coil, or the second half-coil, or both, is preferably translation, i.e., linear movement. The first half-coil and the second half-coil can be in a first operating position, in which the first half-coil and the second half-coil are in contact such that a complete coil is formed and current can flow into the winding of the coil. In this first operating position, each of the half-windings of the first half-coil corresponds to a half-winding of the second half-coil. Furthermore, each half-winding of the first half-coil corresponds to a half-winding of the second half-coil. In this first operating position, the contact between the first and second half-coils allows current to flow into the coil formed by the two half-coils. Therefore, the sensing sensor can detect the characteristics of the sensor. For example, a conductive strip can be formed on the outer surface of the roller, wherein the second half-coil or the first half-coil slides on the outer surface.

[0039] In this system, the strip remains stationary while it is positioned in the seat and the coil is "formed" around it. Therefore, once the strip is positioned on the seat of the roller, it is not necessary to move the strip to obtain a parametric function of the impedance of the sensor. Measurements can be very fast because rapid measurements are possible using an inductive sensor. Complex mechanical parts are not required to move the strip. The strip is protected from deformation due to improper handling within the roller.

[0040] Alternatively, the strip can be pushed into the coil. Insertion of the strip can occur, for example, by injecting a stream of compressed air as the strip is positioned in the seat of the roller. In this case, the coil is stationary, and the strip moves.

[0041] The measurements performed by the sensing sensor are preferably not a single measurement but multiple measurements. These measurements are preferably performed at a fixed frequency. Therefore, the measurement of the impedance function of the coil is preferably repeated multiple times at given time intervals. This repetition is because the parameter function of the coil's impedance changes according to the distance of the first sensor from the coil and, additionally, the degree of insertion of the first sensor inside the coil. The maximum or minimum value of this value is reached when the entire first sensor is inserted inside the coil (depending on how the value is calculated).

[0042] In operation, the strip-shaped article is positioned in the seat of the roller, where the impedance of the coil, modified by the first sensor, is measured by the sensing sensor. The positioning of the strip-shaped article in the seat can be attributed, for example, to a transfer from another roller or from a conveyor.

[0043] When the strip is placed in the seat, current flows along the entire length of the coil, and a parametric function of the impedance can be detected. If the first sensor is not present, no eddy currents are generated, and the magnetic field formed by the coil remains unchanged. Therefore, in this case, the impedance of the coil does not change during insertion. Thus, the "unaltered" impedance value of the coil is the maximum or minimum value to be considered.

[0044] In other cases, the impedance changes when the strip is brought near the coil (or the coil is brought near the strip), and this change is detected by various measurements performed by the sensing sensor. Preferably, the change is detected until the entire first sensor is inserted into the coil. Preferably, the change is also detected when the strip is withdrawn from the coil.

[0045] The measured value of the impedance parameter function of the coil has a maximum or minimum value, or both. This maximum or minimum value is an indicator of the characteristics of the first sensor. In practice, the signal output by the sensing sensor depends on the material, size, shape, and distance of the first sensor. When the material is known and the distance is measurable, the size or shape of the first sensor can be measured. When the size is known (e.g., by knowing the weight), the size of the first sensor can be obtained, for example, from the minimum or maximum value of the signal related to the impedance of the system "coil and first sensor" measured by the sensing sensor, which also depends on the characteristics of the first sensor. In this way, for example, it can be determined whether the sensor is a complete sensor.

[0046] If the maximum or minimum value of the impedance function is not desired through simple and quick measurement, the strip article can be discarded. An unsuitable maximum or minimum value of the impedance function can indicate an overly short first sensor, an overly large first sensor, a first sensor lacking material, a lack of first sensors, or more than one first sensor being inserted together, etc.

[0047] Preferably, the method includes comparing a maximum or minimum value of a parametric function of the impedance with a threshold. Preferably, the method further includes discarding the bar article based on the comparison. Preferably, this comparison can be performed by a control unit electrically connected to the sensing sensor. Preferably, the control unit is adapted to receive a signal from the sensing sensor and compare the signal with a threshold. The sensing sensor preferably measures a parametric function of the impedance of a system formed by a coil and a first sensor. In the first sensor, made of a conductive material, eddy currents are generated, which in turn form a magnetic field. The value of the impedance measured by the sensing sensor depends on the characteristics of the first sensor. In some embodiments of the sensing sensor, the sensing sensor measures resistance. In particular, the sensing sensor is adapted to measure the series resistance equivalent to the first sensor. Preferably, the first sensor is considered acceptable if the maximum resistance of the first sensor measured by the sensing sensor is between 200 milliohms and 500 milliohms. Since the composition of the first sensor is known, comparing the maximum or minimum value of the impedance with a threshold allows the characteristics of the first sensor to be determined.

[0048] Considering that other conductive objects are generally not included in the strip article besides the sensor, there is no change in the impedance of the coil when the first sensor is not present in the strip article.

[0049] Preferably, the method includes measuring the length of the first sensor based on the maximum or minimum value of a parametric function of the coil's impedance during insertion of the strip. The measurement by the sensor may be related to the size of the first sensor. The length of the first sensor can be calculated by examining changes in the signal emitted by the sensor based on the position of the strip within the coil. The signal emitted by the sensor depends on the impedance of the system coil and the first sensor. This parametric function of the impedance reaches its maximum (or minimum) level as the first sensor has entered the coil and begins to decrease (or increase) once the end of the first sensor leaves the coil. The exact length of the first sensor can be determined by comparing this signal with the position of the strip within the coil.

[0050] Preferably, the method includes measuring a parametric function of the coil's impedance as a function of time during insertion of the strip article. The measurement can be performed at a given frequency. The measurement can begin, for example, by detecting the presence of the strip article in the seat of the roller. The frequency can also be variable: for example, a first frequency can be used when the distance between the strip article and the coil exceeds a given distance, and a second frequency can be used when the distance between the strip article and the coil is less than a given distance. Preferably, the second frequency is higher than the first frequency. In this way, further measurements are taken when the coil and the strip article are close to each other or when insertion has occurred. Preferably, the measurement is performed throughout the entire process of inserting the strip article into the coil. Preferably, the method includes the step of removing the strip article from the coil. Preferably, the measurement is performed during the removal of the strip article from the coil.

[0051] More preferably, the method includes: measuring the length of the first sensor based on a curve defined by a parametric function of the impedance of the coil over time during the insertion of the strip article into the coil.

[0052] Preferably, the first sensor has a nominal length, and the step of providing a sensing sensor including a coil for at least one of the plurality of seats of the first roller comprises: providing a sensing sensor including a coil having a length longer than the nominal length of the first sensor for at least one of the plurality of seats of the first roller. To properly evaluate the maximum or minimum value of the parametric function of the impedance, it is preferable to insert the entire sensor into the coil. For this purpose, it is preferable that the coil is longer than the sensor. In a preferred embodiment of the invention, the length of the coil is between 20 mm and 40 mm. The length of the coil is obtained along the coil axis.

[0053] Preferably, the strip-shaped article has a longitudinal axis and the first roller has a rotation axis, and the step of providing a strip-shaped article including a first sensor to at least one of the plurality of seats of the first roller includes: providing a strip-shaped article having a longitudinal axis substantially parallel to the rotation axis to at least one of the plurality of seats of the first roller. The strip-shaped article is preferably moved with its axis parallel to the rotation axis for easy inspection.

[0054] Preferably, the seat has a seat axis and the coil has a coil axis, and the step of providing a sensing sensor including a coil for at least one of the plurality of seats of the first roller includes: providing a seat axis substantially parallel to the coil axis for at least one of the plurality of seats of the first roller. The strip-shaped article is preferably moved with its axis parallel to the axis of rotation for easy inspection. To measure the characteristics of the first sensor, the strip-shaped article is inserted into the coil. If the coil and the strip-shaped article have corresponding axes parallel to each other, the relative movement to be performed between the coil and the strip-shaped article is a simple linear movement. Therefore, the mechanical construction is relatively simple.

[0055] Preferably, the roller has a rotation axis and each of the plurality of seats defines a seat axis, the seat axis and the rotation axis being parallel to each other. Preferably, the seat axes of all seats are parallel to the rotation axis of the first roller. Preferably, all seat axes are parallel to each other. This may also mean that when the strip is located in the seat, the longitudinal axis of the strip is parallel to the rotation axis of the first roller. To determine the characteristics of the first sensor, relative movement between the strip and the coil is required (e.g., half-coil movement, or strip movement, or both). The configuration of the strip being parallel to the rotation axis of the first roller maximizes the number of strips that the first roller can accommodate simultaneously.

[0056] Preferably, the coil has a diameter between 10 mm and 20 mm. The diameter of the coil considered herein is the inner diameter of the coil, i.e., the usable diameter for insertion into the strip-shaped article. The size of the coil allows the strip-shaped article to be inserted.

[0057] Preferably, the strip-shaped article has a first end and a second end, and the first sensor is located at the first end of the strip-shaped article. Preferably, the step of inserting the strip-shaped article into the coil of the sensing sensor includes: inserting the strip-shaped article into the coil of the sensing sensor such that the first end of the strip-shaped article is located within the coil. Preferably, the strip-shaped article causes the first sensor to be "asymmetrically mounted" internally. For example, the first sensor is preferably closer to the first end of the strip-shaped article than to the second end. Therefore, preferably, the insertion of the strip-shaped article into the coil is performed from the first end of the strip-shaped article. In this way, a smaller coil is required to accommodate the entire first sensor.

[0058] Preferably, the step of discarding the strip product based on the maximum or minimum value of the parameter function of the impedance includes: if the maximum or minimum value of the parameter function of the impedance exceeds a preset range, then discard the strip product.

[0059] Preferably, the strip-shaped article has a first end and a second end, and a second sensor, the first sensor being located at the first end of the strip-shaped article and the second sensor being located at the second end of the strip-shaped article. Preferably, the method includes: providing a second roller having a plurality of seats. Preferably, the method includes: providing a sensing sensor including a coil for at least one of the plurality of seats of the second roller. Preferably, the method includes: transferring the strip-shaped article from the first roller to the second roller such that the strip-shaped article is received in at least one of the plurality of seats of the second roller. Preferably, the method includes: inserting the strip-shaped article into the coil of the sensing sensor of the second roller such that the second end of the strip-shaped article is within the coil. Preferably, the method includes: detecting a maximum or minimum value of a parametric function of the impedance of the coil of the sensing sensor of the second roller during insertion of the strip-shaped article. Preferably, the method includes: discarding the strip-shaped article based on the maximum or minimum value of the parametric function of the impedance.

[0060] In some embodiments, the strip article may include two sensors. Therefore, the method uses two rollers: a first roller and a second roller, each of which is used according to the first aspect of the invention described above. Two rollers are used when the strip article includes a first sensor and a second sensor. Preferably, the first sensor and the second sensor are located at two opposite distal ends of the strip article. Therefore, a first sensing sensor measures the impedance of the coil (of the first sensing sensor) modified by the first sensor located at a first end of the strip article. A second sensing sensor measures the impedance of the coil (of the second sensing sensor) modified by a second sensor present at a second end of the strip article. Preferably, in the first roller, the relative movement between the strip article and the coil is along a first axis, while in the second roller, the relative movement between the strip article and the coil is along an axis parallel to the first axis but in the opposite direction. Preferably, after inspection in the first roller, the strip article is transferred to the second roller. Preferably, the transfer is performed only if the first sensor is defect-free. The transfer is performed according to standard methods in the art. Therefore, it enables a rapid and complete test of both the first and second receptors.

[0061] Preferably, the first roller and the second roller have the same characteristics. Therefore, the second roller has the same characteristics as described above with reference to the first roller.

[0062] Preferably, the first receptor and the second receptor have the same characteristics. Therefore, the second receptor has the same characteristics as described above with reference to the first receptor.

[0063] Preferably, the sensing sensors in the first roller and the sensing sensors in the second roller have the same characteristics. Therefore, the sensing sensor in the second roller has the same characteristics as described above with reference to the sensing sensor in the first roller.

[0064] Preferably, the step of inserting the strip-shaped article into the coil of the sensing sensor includes: sliding the strip-shaped article on the bottom surface of the base to insert the strip-shaped article into the coil. More preferably, the step of sliding the strip-shaped article on the bottom surface of the base to insert the strip-shaped article into the coil includes: pushing the strip-shaped article into the coil by means of an airflow. For example, the airflow can be generated by a compressed air system. The compressed air system may include a nozzle adapted to inject compressed air flow. The main direction of the compressed air flow is preferably parallel to the longitudinal axis of the base. Therefore, preferably, the compressed air flow impacts one end of the strip-shaped article and pushes it toward the coil. Preferably, the coil is aligned with the base, that is, the longitudinal axis of the coil is parallel to or coincides with the longitudinal axis of the strip-shaped article. Preferably, the longitudinal axis of the coil is parallel to the average axis of the compressed air flow.

[0065] Preferably, the compressed air system includes a second nozzle for injecting a compressed air flow opposite to the first compressed air flow to push the strip-shaped article outside the coil. Preferably, the second nozzle faces the first nozzle at a given distance. Preferably, the given distance is longer than the length of the strip-shaped article. Preferably, the first nozzle and the second nozzle are located on opposite sides of the coil.

[0066] Preferably, the coil includes a first half-coil and a second half-coil, which are movable from a first operating position to a second operating position. In the first operating position, the first half-coil and the second half-coil are in contact with each other, thereby forming a coil in which current can flow. In the second operating position, the first half-coil and the second half-coil are separated from each other and no current can flow, and vice versa. Preferably, the step of inserting the strip into the coil of the sensing sensor includes moving the first half-coil and the second half-coil from the second operating position to the first operating position. Preferably, when the strip is positioned in the seat, the first half-coil and the second half-coil are separated from each other in the second operating position, so that the volume above the seat is "free" and the strip can be positioned in the seat without any obstruction. When the strip is in the seat, moving the first half-coil and the second half-coil to the first operating position allows for the detection of the characteristics of the sensor. Therefore, the actuator moves either the first half-coil or the second half-coil until the half-winding of the first half-coil corresponds to the complementary half-winding of the second half-coil. The control unit commands the actuator to move the second half-coil until it reaches the first operating position. The command from the control unit can be triggered by another sensor that senses the presence or absence of the strip-shaped article in the seat. Therefore, when the sensor senses the presence of the strip-shaped article, it sends a signal to the control unit, which then sends a signal to the actuator to position the first half-coil and the second half-coil in the first operating position, and this can be detected by the sensing sensor. Alternatively, the command sent by the control unit to the actuator is synchronized with the rotation of the first roller. As the first roller rotates, the control unit is adapted to receive or determine the roller angular velocity and the insertion point of the strip-shaped article in the first roller. Based on this information, the control unit can calculate the angular position of each strip-shaped article in the first roller. The control unit can command the actuator in the seat where the sensing sensor is located to move the first half-coil and the second half-coil from the second operating position to the first operating position at a given frequency.

[0067] Preferably, the method includes the following steps: calibrating the sensing sensor using a strip comprising a first sensor or a second sensor or both, having a length equal to the nominal length.

[0068] Preferably, the step of discarding the strip article is performed by a rejection device adapted to reject the strip article based on the maximum or minimum value of a signal emitted by the sensing sensor as a parameter function of the impedance. If the sensing sensor senses that one of the characteristics of the first receptors inside the strip article is outside the specifications, such as the first receptor being absent or its length being too short or too long, the strip article is preferably not further processed. For example, the strip article containing the "defective" first receptor is transferred to a rejection roller, which is different from the first roller in which strip articles containing valid receptors are transferred. Preferably, the control unit controls a suction system that holds the strip article in the seat such that the strip article containing the defective receptor is discharged from the seat differently from the strip article containing the valid receptor. Preferably, the distinction between valid and defective receptors is made by the control unit. Preferably, the distinction is based on the characteristics of the receptors sensed by the sensing sensor.

[0069] "Impedance" represents the complex value of resistance. Impedance Z is a complex number representing V (voltage) / I (current). In the case of an ideal inductor L (such as a coil), the impedance Z... L Given by the following formula:

[0070] Z L =jωL

[0071] Where j is the imaginary unit, ω is the angular frequency of the excitation signal, and L is the inductance of the coil.

[0072] The equivalent resistance R of the coil, measured in ohms, is ωL.

[0073] In the following text, the term "strip article" may refer to any element or the entire aerosol-generating article that may be included in an aerosol-generating article. Such elements are known in the art and will not be described in detail below. For example, such strip articles may include filter sections of a filter, a heat source, tobacco strips, charcoal elements, etc. Preferably, the strip article is an article containing plant material, particularly tobacco. The tobacco article may contain shredded tobacco filler or reconstituted tobacco that forms an aerosol. The article may include tobacco strips to be burned or heated. The strip article according to the invention may be an entire assembled aerosol-generating article or an element of an aerosol-generating article, said element being combined with one or more other components to provide an assembled aerosol-generating article for generating aerosols, said element being, for example, a consumable component of a heated smoking device.

[0074] Preferably, the components of the aerosol-generating article include a tobacco-containing material, which includes volatile tobacco flavor compounds that are released from the aerosol-generating matrix upon heating.

[0075] Preferably, the strip-shaped product may include a heat source or a volatile flavor-generating component, such as a menthol capsule, a charcoal element, or a receptor.

[0076] Furthermore, the strip-shaped article may include multiple components of an aerosol-generating article combined together, or even more than one aerosol-generating article.

[0077] As used herein, the term "receptor" refers to a material capable of converting electromagnetic energy into heat. When placed in an alternating electromagnetic field, eddy currents are induced in the receptor, and hysteresis losses occur, thereby causing the receptor to heat up. When the receptor is positioned in thermal contact or close thermal proximity with the aerosol-forming matrix, the aerosol-forming matrix is ​​heated by the receptor to form an aerosol. Preferably, the receptor is arranged in direct physical contact with the aerosol-forming matrix, for example, within an aerosol-forming tobacco matrix.

[0078] The receptor can be formed from any material capable of being inductively heated to a temperature sufficient to generate aerosols from the aerosol-forming matrix. Preferred receptors may comprise or be composed of ferromagnetic materials, such as ferromagnetic alloys, ferritic iron, or ferromagnetic steel or stainless steel. Suitable receptors may be aluminum or include aluminum. Preferred receptors can be heated to temperatures exceeding 250 degrees Celsius. Suitable receptors may include a non-metallic core having a metallic layer disposed on the non-metallic core, such as metallic traces formed on the surface of a ceramic core. The receptor may have an outer protective layer, such as a ceramic or glass protective layer encapsulating the receptor. The receptor may include a protective coating formed of glass, ceramic, or an inert metal, which is formed on the core of the receptor material.

[0079] The sensor can be a multi-material sensor and may include a first sensor material and a second sensor material. The first sensor material is disposed in close physical contact with the second sensor material. The second sensor material preferably has a Curie temperature below 500°C. The first sensor material is preferably primarily used to heat the sensor when it is placed in a fluctuating electromagnetic field. Any suitable material can be used. For example, the first sensor material can be aluminum, or it can be an iron-containing material, such as stainless steel. The second sensor material is preferably primarily used to indicate when the sensor has reached a specific temperature, which is the Curie temperature of the second sensor material. The Curie temperature of the second sensor material can be used to regulate the temperature of the entire sensor during operation. Therefore, the Curie temperature of the second sensor material should be below the ignition point of the aerosol-forming matrix. Suitable materials for the second sensor material may include nickel and certain nickel alloys.

[0080] Preferably, the receptor is in the form of a filament, strip, sheet, or tape. If the receptor profile has a constant cross-section, such as a circular cross-section, it has a preferred width or diameter between about 1 mm and about 5 mm. If the receptor profile is in the form of a sheet or tape, the sheet or tape preferably has a rectangular shape with a width preferably between about 2 mm and about 8 mm, more preferably between about 3 mm and about 5 mm (e.g., 4 mm), and a thickness preferably between about 0.03 mm and about 0.15 mm, more preferably between about 0.05 mm and about 0.09 mm (e.g., 0.07 mm).

[0081] Preferably, the length of the strip article can be between about 5 mm and about 20 mm, more preferably between about 8 mm and about 16 mm, for example, about 12 mm. In some cases, the length of the strip article can be from about 40 mm to about 85 mm.

[0082] In the following text, unless otherwise specified, the term "length" refers to the length of a strip of writing along its longitudinal axis.

[0083] In the following text, the term "bar" refers to a generally cylindrical element with a generally cylindrical, oval, or elliptical cross-section. However, other prismatic forms with different cross-sections are also possible.

[0084] As used herein, "aerosol-generating article" refers to any article that generates an inhalable aerosol when an aerosol-forming matrix is ​​heated. The term includes articles comprising an aerosol-forming matrix heated by an external heat source, such as an electrothermal element. An aerosol-forming article can be a non-flammable aerosol-generating article, which releases volatile compounds without causing the aerosol-forming matrix to burn. An aerosol-forming article can be a heated aerosol-generating article, which is an aerosol-generating article comprising an aerosol-forming matrix intended to be heated rather than burned to release volatile compounds that can form aerosols. The term includes articles comprising an aerosol-forming matrix and an integrated heat source (e.g., a flammable heat source).

[0085] The aerosol generating article may include a mouthpiece element. The mouthpiece element may be located at the inlet or downstream end of the aerosol generating article.

[0086] Aerosol-generating articles may include at least one filter element.

[0087] The filter section can be a cellulose acetate filter tip section made of cellulose acetate tow. The filter section can have low or very low particulate filtration efficiency. The filter section can be longitudinally spaced from the aerosol forming matrix. The filter section can have a longitudinal length between approximately 5 mm and approximately 14 mm. The length of the filter section can be approximately 7 mm.

[0088] The multiple components of an aerosol-generated article may include at least one of a support element and an aerosol cooling element.

[0089] Preferably, the aerosol-generating article includes a package containing multiple elements of the aerosol-generating article in the form of a strip. The package may include at least one of paper and foil.

[0090] As used herein, the term "aerosol forming matrix" refers to a matrix formed by or comprising an aerosol forming material that, upon heating, releases volatile compounds to generate aerosols. The aerosol forming matrix may contain tobacco material, or may contain non-tobacco material, or a combination of both. The aerosol forming matrix may be a nicotine-impregnated cellulose material, preferably comprising one or more flavoring agents. Advantageously, the aerosol forming matrix comprises tobacco material, preferably homogenized tobacco material, which preferably comprises one or more aerosol forming agents. As used herein, the term "homogenized tobacco material" refers to a material formed by agglomerating particulate tobacco.

[0091] Preferably, the aerosol forming matrix contains volatile tobacco flavor compounds released from the aerosol forming matrix upon heating. The aerosol forming matrix may include or consist of a mixture of tobacco shredded fillers, or may include homogenized tobacco material. Homogenized tobacco material can be formed by agglomerating particulate tobacco. The aerosol forming matrix may additionally include tobacco-free materials, such as homogenized plant-based materials other than tobacco.

[0092] Preferably, the aerosol forming matrix is ​​a tobacco sheet (preferably pressed), comprising tobacco material, fibers, binder, and aerosol forming agent. Preferably, the tobacco sheet is a cast leaf. Cast leaves are in the form of reconstituted tobacco formed from a pulp, said pulp comprising tobacco particles, fiber particles, aerosol forming agent, binder, and, for example, flavoring agents.

[0093] Depending on the desired sheet thickness and casting gap, the tobacco particles can be in the form of tobacco dust, having a particle size of about 30 micrometers to 250 micrometers, preferably about 30 micrometers to 80 micrometers or 100 micrometers to 250 micrometers, wherein the casting gap typically defines the sheet thickness. The size of the tobacco particles refers to the Dv95 size in its volume distribution.

[0094] It may also include fibrous microparticles, which include tobacco stem material, stalks or other tobacco plant material, and other cellulose-based fibers, such as woody fibers with low lignin content. The fiber particles can be selected based on the expectation of producing sufficient tensile strength for the cast leaves relative to a low impurity rate (e.g., between approximately 2% and 15%). Alternatively, plant fibers, such as bamboo, can be used with the aforementioned fiber particles, or, in an alternative, bamboo may be included.

[0095] Aerosol forming agents can be selected based on one or more characteristics, either as part of the slurry forming the cast leaf or as part of other aerosol-forming matrices. Functionally, the mechanism provided by the aerosol forming agent allows it to volatilize when heated above its specific volatilization temperature and deliver nicotine or flavoring, or both, in the aerosol. Different aerosol forming agents typically vaporize at different temperatures. An aerosol forming agent can be any suitable known compound or mixture of compounds that promotes the formation of a dense and stable aerosol in use and is substantially resistant to thermal degradation at the operating temperatures of the induction heating device with which the induction-heated tobacco matrix will be used. Aerosol forming agents can be selected based on, for example, their ability to remain stable at or near room temperature but to volatilize at higher temperatures, such as between 40°C and 450°C.

[0096] Aerosol forming agents can also possess wetting agent properties, which help maintain desired levels of moisture in the aerosol forming matrix when the matrix is ​​composed of tobacco-based products that specifically include tobacco particles. Specifically, some aerosol forming agents are hygroscopic materials that act as wetting agents, i.e., materials that help keep the tobacco matrix containing the wetting agent moist.

[0097] One or more aerosol forming agents can be combined to utilize one or more properties of the combined aerosol forming agents. For example, triacetylglycerol can be combined with glycerol and water to utilize the ability of triacetylglycerol to deliver the active ingredient and the wetting properties of glycerol.

[0098] The aerosol forming agent may be selected from polyols, glycol ethers, polyol esters, esters, and fatty acids, and may include one or more of the following compounds: glycerol, erythritol, 1,3-butanediol, tetraethylene glycol, triethylene glycol, triethyl citrate, propylene carbonate, ethyl laurate, triacetin, meso erythritol, a mixture of diacetins, diethyl octanoate, triethyl citrate, benzyl benzoate, benzyl phenyl acetate, ethyl vanillate, glyceryl tribanoate, lauryl acetate, lauric acid, myristic acid, and propylene glycol.

[0099] The aerosol forming matrix may include other additives and ingredients, such as fragrances. Preferably, the aerosol forming matrix includes nicotine and at least one aerosol forming agent.

[0100] The aerosol-generating articles according to the present invention can be in the form of combustible filter cigarettes or other smoking articles, wherein tobacco materials are burned to form smoke.

[0101] Preferably, the aerosol-generating article can be generally cylindrical in shape. The aerosol-generating article can be generally elongated. The aerosol-generating article can have a length and a circumference generally perpendicular to said length. The total length of the aerosol-generating article can be between about 30 mm and about 100 mm, more preferably between 40 mm and 55 mm. The outer diameter of the aerosol-generating article can be between about 5 mm and about 12 mm, more preferably between 6 mm and 8 mm.

[0102] The invention is defined in the claims. However, a non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0103] Example Ex1: A method for inspecting strip-shaped articles, the method comprising:

[0104] o provides a first roller having multiple seats;

[0105] o provides a sensing sensor including a coil for at least one of the plurality of seats of the first roller;

[0106] o provides at least one of the plurality of seats of the first roller with a strip article including a first sensor, the first sensor including a conductive material;

[0107] o Insert the strip-shaped product into the coil of the sensing sensor;

[0108] o Detect the maximum or minimum value of a parameter function of the coil's impedance during insertion of the strip;

[0109] The strip is discarded based on the maximum or minimum value of the parameter function of the impedance.

[0110] Example Ex2: The method described in Ex1 includes:

[0111] o compares the maximum or minimum value of the parameter function of the impedance with a threshold;

[0112] o Discard the strip-shaped product based on the comparison.

[0113] Example Ex3: The method described according to Ex1 or Ex2 includes:

[0114] During insertion of the strip, the length of the first sensor is measured based on the maximum or minimum value of a parameter function of the coil's impedance.

[0115] Example Ex4: The method described in one or more of the preceding Ex1–Ex3 includes:

[0116] o A parametric function measuring the impedance of the coil as a function of time during insertion of the strip.

[0117] Example Ex5: The method described in Ex4 includes:

[0118] During the insertion of the strip into the coil, the length of the first sensor is measured based on a curve defined by a parametric function of the coil's impedance changing over time.

[0119] Example Ex6: According to one or more of the methods described in Ex1–Ex5 above, wherein the first sensor has a nominal length, and the step of providing a sensing sensor including a coil for at least one of the plurality of seats of the first roller includes:

[0120] o provides at least one of the plurality of seats of the first roller with a sensing sensor including a coil having a length longer than the nominal length of the first sensor.

[0121] Example Ex7: According to one or more of the methods described in Ex1-Ex6 above, wherein the strip article has a longitudinal axis and the first roller has a rotation axis, and wherein the step of providing the strip article including a first sensor to at least one of the plurality of seats of the first roller includes:

[0122] o provides at least one of the plurality of seats of the first roller with a strip-shaped article having a longitudinal axis that is substantially parallel to the axis of rotation.

[0123] Example Ex8: According to one or more of the methods described in Ex1-Ex7 above, wherein the strip-shaped article has a first end and a second end, and the first sensor is located at the first end of the strip-shaped article, and wherein the step of inserting the strip-shaped article into the coil of the sensing sensor includes:

[0124] o Insert the strip-shaped product into the coil of the sensing sensor such that the first end of the strip-shaped product is located within the coil.

[0125] Example Ex9: According to one or more of the methods described in Ex1–Ex8 above, the step of discarding the strip article based on the maximum or minimum value of the impedance includes:

[0126] If the maximum or minimum value of the parameter function of the impedance exceeds a preset range, the strip product is discarded.

[0127] Example Ex10: A method for inspecting a strip-shaped article according to one or more of the preceding Ex1-Ex9, wherein the strip-shaped article has a first end and a second end, and a second sensor, the first sensor being located at the first end of the strip-shaped article and the second sensor being located at the second end of the strip-shaped article, and wherein the method includes:

[0128] o provides a second roller with multiple seats;

[0129] o provides a sensing sensor including a coil for at least one of the plurality of seats of the second roller;

[0130] o Transfer the strip-shaped article from the first roller to the second roller such that the strip-shaped article is received in at least one of the plurality of seats of the second roller;

[0131] o Insert the strip-shaped product into the coil of the sensing sensor of the second roller, such that the second end of the strip-shaped product is inside the coil;

[0132] o During insertion of the strip, detect the maximum or minimum value of the parameter function of the coil's impedance;

[0133] The strip is discarded based on the maximum or minimum value of the parameter function of the impedance.

[0134] Example Ex11: According to one or more of the methods described in Ex1–Ex10 above, the step of inserting the strip-shaped article into the coil of the sensing sensor includes:

[0135] o Slide the strip on the bottom surface of the seat to insert the strip into the coil.

[0136] Example Ex12: According to the method in Ex11, the step of sliding the strip-shaped article on the bottom surface of the seat to insert the strip-shaped article into the coil includes:

[0137] The strip is pushed into the coil by means of an airflow.

[0138] Example Ex13: According to one or more of the methods in Ex1-Ex10, wherein the coil includes a first half-coil and a second half-coil, the first half-coil and the second half-coil being movable from a first operating position to a second operating position, in the first operating position, the first half-coil and the second half-coil being in contact with each other to form the coil in which current can flow, and in the second operating position, the first half-coil and the second half-coil being separated from each other and no current can flow, and vice versa, wherein the step of inserting the strip into the coil of the sensing sensor includes:

[0139] o moves the first half-coil and the second half-coil from the second operating position to the first operating position.

[0140] Example Ex14: According to one or more of the methods described in Ex1–Ex13 above, the method includes the following steps:

[0141] The sensing sensor is calibrated using a strip comprising a first sensor or a second sensor, or both, whose length is equal to the nominal length.

[0142] Example Ex15: According to one or more of the methods described in Ex1-Ex14 above, wherein the strip article includes a component of an aerosol-generated article.

[0143] Example Ex16: According to one or more of the methods described in Ex1-Ex15 above, wherein the impedance of the coil is a parametric function of the impedance Z of the coil itself, or the equivalent resistance R of the coil, or the inductance L of the coil.

[0144] Example Ex17: According to one or more of the methods described in Ex1-Ex16 above, wherein the strip article comprises an aerosol-generating article or a component of an aerosol-generating article.

[0145] Example Ex18: According to the method of Ex17, the aerosol generating article includes an aerosol forming matrix.

[0146] Example Ex19: The method according to Ex18, wherein the aerosol forming matrix comprises homogenized tobacco material.

[0147] Example Ex20: The method according to Ex18 or Ex19, wherein the aerosol forming matrix surrounds the receptor.

[0148] Example Ex21: A method for producing a strip article comprising an aerosol-generating article or a component of an aerosol-generating article comprising an aerosol-forming matrix, the method comprising the step of inspecting the strip article according to one or more of the methods described in the preceding Ex1-Ex20. Attached Figure Description

[0149] Several examples will now be described further with reference to the accompanying drawings, in which:

[0150] · Figure 1 A partial cross-sectional perspective view of a strip-shaped article including a receptor, to be inspected according to the method of the present invention;

[0151] · Figure 2 for Figure 1 A side view of a strip-shaped product;

[0152] · Figure 3 A perspective view of an inspection device with a first configuration operating according to a first embodiment of the present invention;

[0153] · Figure 4 A perspective view of an inspection device operating according to a second embodiment of the present invention;

[0154] · Figure 5 for Figure 4 A top view of the inspection device in chronological order;

[0155] · Figure 6 A series of steps for the operation of the sensing sensor present in the inspection device of the present invention;

[0156] · Figure 7 for Figure 3 , Figure 4 or Figure 5 Detailed cross-sectional views of the components of the inspection device;

[0157] · Figure 8 for Figure 7 Front view of the component;

[0158] · Figure 9 This is a side view of another embodiment of the strip-shaped article to be inspected according to the present invention;

[0159] · Figure 10 This is a third embodiment of the inspection apparatus operating according to the present invention;

[0160] · Figure 11 and Figure 12 for Figure 10 Two magnified views of two details in two different embodiments;

[0161] · Figure 13 and Figure 14 They are respectively Figure 3 Two cross-sectional views of the coil in the first and second configurations of the inspection device of the first embodiment. Detailed Implementation

[0162] First refer to Figure 1 and Figure 2 The example of a bar-shaped product is indicated by the number 60.

[0163] Preferably, the strip article 60 includes several components of an aerosol-generating article, such as the entire aerosol-generating article.

[0164] The aerosol-generating article 60 includes, for example, multiple elements assembled in the form of a strip. The multiple elements may include a filter segment element 11, an aerosol-forming matrix 10 in the form of a tobacco stick, a receptor material 12 positioned within the aerosol-forming matrix 10, a hollow cellulose acetate tube 16, another hollow cellulose acetate tube 18, a mouthpiece 2, and an outer packaging 22. The aerosol-generating article 60 includes a mouth end 24 and a distal end 26. The strip-shaped article 60 defines a longitudinal axis 61.

[0165] Preferably, the plurality of elements listed above are formed one after another along the longitudinal axis 61 of the strip article 60. Preferably, all elements have the same diameter.

[0166] Preferably, the cross-section of the strip-shaped article 60 along a plane perpendicular to its longitudinal axis 61 is circular.

[0167] The strip-shaped article 60 includes an outer surface 13 (preferably generally cylindrical) extending along a longitudinal axis 61. The longitudinal axis 61 of the strip-shaped article 60 may correspond to the axis of a cylinder.

[0168] The aerosol forming matrix 10 may include homogenized tobacco material.

[0169] The receptor 12 is preferably in thermal contact with the aerosol forming matrix 10, such that when the receptor is inductively heated, heat is transferred to the aerosol forming matrix 10 and thereby releases aerosol. Preferably, the receptor 12 is completely surrounded by the tobacco material forming the aerosol forming matrix 10.

[0170] like Figure 1 and Figure 2 As shown in the example, the receptor 12 is completely contained within the strip article 60, more preferably it is completely contained within the aerosol forming matrix 10.

[0171] The receptor 12 is made of a conductive material. Preferably, the receptor is made of a metal, and in some embodiments, the receptor is made of a ferromagnetic material.

[0172] According to a preferred embodiment, such as Figure 1 and Figure 2 As shown, receptor 12 has a strip shape. Alternatively, the receptor may have a strip shape. Preferably, the thickness of the receptor is between 30 micrometers and 60 micrometers. Preferably, the length of the receptor is between 5 millimeters and 20 millimeters.

[0173] Figure 3 A portion of a preferred embodiment of the roller 4 of the inspection device 100 according to a first aspect of the present invention is shown.

[0174] For clarity, in Figure 3 The inspection device 100 is only partially shown in the image.

[0175] As will be apparent from the following description, the inspection device 100 is adapted to control the quality of the strip article 60, particularly the sensor 12.

[0176] The quality control provided by the inspection device 100 may require checking the presence, integrity, or precise location of the sensor 12, as well as further characteristics of the sensor.

[0177] As a non-limiting example, such characteristics may include one or more of the following characteristics: the length of the receptor, the thickness of the receptor, the deviation of the receptor from linear development, the deviation of the axis of the receptor from the parallelism of the longitudinal axis 61 of the strip 60, and the electromagnetic properties of the receptor.

[0178] Furthermore, the quality control can be performed at any stage of the manufacturing process of the aerosol-generating article. This means that the strip article 60 can be inspected when the aerosol-forming matrix 10 is bonded to the mouthpiece filter element 2 or to any other component to which it is to be fixed, or the aerosol-forming matrix 10 including the sensor 12 can be inspected separately.

[0179] Refer again Figure 3 The roller 4 includes a plurality of seats 41, each seat being adapted to receive strip-shaped articles 60. The seats 41 are preferably located on the outer surface 40 of the roller 4. Preferably, there are about 20 to 60 seats 41 in the roller 4, preferably about 40 seats.

[0180] In some embodiments, the roller 4 is cylindrical, and preferably the outer surface 40 of the seat 41 is positioned thereon, corresponding to the lateral surface of the cylinder.

[0181] It should be understood that the size and shape of the seat portion 41 are preferably configured to at least partially receive the strip article 60. Preferably, the size and shape of the seat portion 41 are selected to receive the strip article 60. More generally, quality control preferably includes positioning the strip article 60 in one of the seat portions 41.

[0182] The strip article 60 can be positioned by using a suitable positioning device (not shown) or by transferring the strip article 60 from another roller or conveyor in any other possible way.

[0183] In some embodiments, the inspection device 100 may be included in an apparatus for manufacturing aerosol-generating articles, and the strip article 60 may be transferred from a conveyor element of the apparatus to the inspection device 100.

[0184] Preferably, the roller 4 is a rotating roller having a rotation axis 67. Therefore, the roller 4 allows the strip-shaped product 60 to be transferred from a first position to a second position, preferably forming an inlet and an outlet position, where the strip-shaped product is positioned on the seat and where it is removed from the seat at the outlet position. First position and second position ( Figure 3 (Not depicted in the text) Separated by rotating the rollers at an angle.

[0185] In some embodiments, the seat portion 41 may be oblong to define a corresponding seat axis 42. Preferably, the seat axis 42 and the rotation axis 67 of the seat portion 41 are parallel to each other. Preferably, all axes 42 of the plurality of seats 41 are parallel to each other.

[0186] The seat portion 41 is preferably formed on the outer surface 40 of the roller 4. The seat portion 41 may be in the form of a recess implemented on the outer surface 40 of the roller 4.

[0187] However, it is obvious that the seat 41 may be defined by other elements on the outer surface of the roller 4, for example, fixed to the outer surface and protruding radially from the outer surface.

[0188] Preferably, roller 4 defines a front 64 and a rear (not visible in the figure). The rear is axially opposite to the front 64.

[0189] In some embodiments, the seat portion 41 extends from the front 64 to the rear, i.e., the seat portion may be provided with opposite open ends.

[0190] In this manner, the strip article 60 can be received in the seat 41 by approaching the seat laterally, preferably by sliding along the direction defined by the axis 42 of the seat.

[0191] like Figure 3 As shown in the embodiments, the length of the seat portion 41 can be at least equal to the length of the strip article 60 to be inspected. A longer seat portion 41 can also be used, thereby allowing the strip article 60 to slide therein.

[0192] In some embodiments, the axis of rotation 67 of the roller 4 is substantially horizontal.

[0193] The seat 41 can be configured such that when the seat reaches a specific angular position along the axis of rotation 67, the strip product 60 is discharged from the seat 41, in which gravity acts on the strip product 60 to release the strip product from the roller 4.

[0194] The inspection device 100 further includes a sensing sensor 5 located at least at one of the plurality of seats 41. It should be understood that, although... Figure 3 The embodiment shows a single sensing sensor 5 positioned at a specific seat 41, but each seat 41 of the roller 4 may include a corresponding sensing sensor 5.

[0195] Alternatively, according to another possible embodiment, the sensing sensor 5 may be disposed at a selected seat portion 41 at a predetermined angular distance, for example.

[0196] Preferably, the sensing sensor 5 includes a coil 51 defining an internal volume 50, the internal volume being large enough to receive at least one end of the strip article 60 therein.

[0197] Figure 7 and Figure 8 A coil 51 according to a preferred embodiment is shown.

[0198] Preferably, the coil 51 defines a coil axis 70 and has an inner diameter 71, which is between 10 mm and 18 mm, and more preferably between 12 mm and 16 mm. Preferably, the inner diameter 71 of the coil 51 is 14 mm.

[0199] It should be understood that the aforementioned diameter was chosen to make the coil 51 wide enough to receive the opening end 24 or the distal end 26 of the strip article 60, but at the same time to avoid using bulky components in the inspection device 100.

[0200] In some embodiments, the length of the coil 51 is adapted to completely accommodate the strip article 60 therein.

[0201] Preferably, the length 72 of the coil is between 20 mm and 40 mm, more preferably between 25 mm and 35 mm. Preferably, the length 72 of the coil 51 is 32 mm.

[0202] In some embodiments, the coil 51 is formed of a pair of parallel wound wires.

[0203] Preferably, coil 51 has a total number of turns between 26 and 46. More preferably, the number of turns is between 30 and 42. Preferably, the number of turns is 32.

[0204] In the case where coil 51 is formed by a pair of wires, each wire may include half of the total number of turns mentioned above.

[0205] The coil 51 is preferably cylindrical. Preferably, the coil 51 is positioned at the base such that the coil axis 70 is parallel to the base axis 42.

[0206] The presence of the sensor 12 in the strip article 60 can be sensed by moving the strip article 60 relative to the coil 51 and by taking into account the change in the feedback signal generated by the interaction between the sensor 12 and the coil 51.

[0207] Therefore, in such Figure 3 In some embodiments shown, the inspection device 100 includes a control unit 7 electrically connected to the sensing sensor 5 and adapted to receive signals from the sensing sensor 5 and compare them with a threshold in order to detect changes in the signal caused by the presence of the sensor 12.

[0208] It should be understood that this can be achieved by moving coil 51 relative to strip 60 (e.g., Figure 3 (as in the example) or to move the strip 60 relative to the coil 51 (e.g. Figure 4 or Figure 5 (In the embodiments) this change in signal is caused.

[0209] Generally, it should be understood that the sensing sensor 5 can generate an alternating magnetic field in the coil 51, which is modified as the sensor 12 passes through it. More generally, the sensing sensor 5 is configured to generate an alternating magnetic signal in a detection direction preferably corresponding to the axis 70 of the coil 51.

[0210] Preferably, when the first ends 24, 26 of the strip 60 in which the sensor 12 is assumed to be positioned are received in the internal volume 50 of the coil 51 of the sensor 5, the magnetic field generated by the sensor 5 is modified.

[0211] In other words, the magnetic field generated by the sensor 12 passing through the internal volume 50 of the sensor 5 acts on the magnetic field generated by the sensor 5, that is, the magnetic field generated by the coil 51. According to Lenz's law, the sensor 12 acts as a resistor in the coil 51, or more generally in the sensor 5.

[0212] More specifically, when a ferromagnetic material enters a magnetic field, an electromagnetic force is induced within it (Maxell-Faraday's law), which generates alternating eddy currents. These alternating currents generate an induced magnetic field (Maxell-Ampere's law), which is opposite to the sensor's magnetic field (Lenz's law).

[0213] The presence or absence of the receptor 12 in the strip article 60 can be determined accordingly based on such expected behavior in the magnetic field. If no alternation occurs when the strip article 60 passes through the alternating magnetic field generated by the coil 51, then the receptor 12 cannot be present in the strip article 60.

[0214] In contrast, the alternation can be determined by calculating the impedance of the strip 60, which varies as the sensor 12 passes through the internal volume 50 of the coil 51, as previously explained.

[0215] According to a preferred embodiment, the feedback signal generated when the receptor 12 passes through the internal volume 50 can be used to determine other characteristics of the receptor 12.

[0216] refer to Figure 6 The feedback signal could be used to determine the length of the receptor 12.

[0217] Figure 6 This illustrates how the equivalent resistance of the system “coil and sensor” changes according to the relative position of sensor 12 in the internal volume 50.

[0218] First, before the strip-shaped product 60 enters the internal volume 50, the feedback signal output by the sensing sensor 5 is not modified.

[0219] As the strip-shaped product 60 enters the internal volume 50, the feedback signal changes.

[0220] When the entire sensor 12 has been fully inserted into the internal volume 50, the feedback signal will reach a minimum level, and once the end of the sensor 12 leaves the coil 51, the feedback signal will begin to decrease.

[0221] The length of the receptor 12 can be determined by comparing the signal with the position of the strip 60 within the internal volume 50.

[0222] Preferably, the length of the sensor 12 is estimated based on the peak value of the measured equivalent resistance determined after appropriate calibration.

[0223] Alternatively, when the sensor is fully inserted into the coil, the parameter function of the impedance shows a maximum value instead of a minimum value.

[0224] In such embodiments, also based on the previously mentioned characteristics of the coil, the internal volume 50 of the coil 51, or more generally the inductive sensor 5, is longer than the intended length of the sensor 12.

[0225] Preferably, the length of the coil 51 is selected to be at least 10 mm / side longer than the expected length of the sensor 12 in order to avoid magnetic field distortion at the ends of the coil.

[0226] According to a preferred embodiment, the control unit 7 is configured to determine whether the length of the sensor 12 corresponds to a expected value by examining changes in the feedback signal based on the position of the strip 60 in the internal volume 50.

[0227] It should be understood that the control unit 7 may also be adapted to calculate the length of the sensor 12 located in the strip article 60 according to different methods, such as generally taking into account other specific behaviors of the sensing sensor 5 during the interaction of the strip article 1 with the internal volume 50.

[0228] More generally, the equivalent resistance of the feedback signal can indicate the nature or consistency of the shape or composition of the receptor 12. Therefore, additional characteristics of the receptor 12 can be determined by the inspection device 100 of the present invention.

[0229] In order to introduce the strip 60 into the coil 51, Figure 3 In the inspection device 100, the coil 51 is divided into two half-coils 65 and 66. The first half-coil 66 is positioned below the outer surface 40 of the roller 4, while the second half-coil is positioned above the outer surface 40 of the roller. The two half-coils 65 and 66 can be... Figure 13 The first operating position movement shown forms coil 51. In this first operating position, actions can be performed by the sensing sensor, and for example... Figure 6 The above measurements are shown in the figure. Figure 3 and Figure 13 In the second operating position depicted, the second half-coil 65 moves along the coil axis 70 and away from the first half-coil, so that the strip 60 can be positioned in the seat 41. The movement is performed by means of an actuator 6 connected to the control unit 7.

[0230] exist Figure 3 , Figure 13 and Figure 14 In the inspection device 100, during operation, a strip-shaped product 60 is inserted into the seat 41. When the strip-shaped product is positioned in the seat, the first half-coil 66 and the second half-coil 65 are in a second operating position, that is, the two half-coils 65 and 66 are separated from each other, as... Figure 3 and Figure 14 As shown in the diagram. Once the strip 60 is in the seat, the first half-coil 66 and the second half-coil 65 are moved to... Figure 13 The first operating position is such that measurement can be performed using the sensing sensor 5. The relative movement of the first half-coil and the second half-coil is as follows: the first half-coil 66 is positioned below the outer surface 40 and is fixed relative to said outer surface, while the second half-coil 65 moves from... Figure 14 The first operating position is moved back and forth to Figure 3 and Figure 14The second operating position is reached, and vice versa. Movement of the second half-coil 65 from the first operating position to the second operating position is achieved by means of the piston 69 connected to the actuator 6, and vice versa. Figure 3 As indicated by arrow 68, piston 69 is attached to the second half-coil so that it moves linearly toward and away from the first half-coil.

[0231] exist Figure 4 and Figure 5 In the different embodiments of the invention depicted, instead of as in Figure 3 , Figure 13 and Figure 14 In this embodiment, the coil is moved relative to the strip-shaped article, causing the strip-shaped article 60 to move relative to the coil 51. In the inspection device 200, the same reference numerals as in the inspection device 100 are used to designate the same elements. In the inspection device 200, the sensing sensor 5 includes a coil 51, which in this case is attached to the outer surface 40 of the roller 4. The coil 51 (in...) Figure 7 and Figure 8 (See better in the image) For example, located at one end of the seat 41. The inspection device 200 includes compressed air systems 8 and 9, which include a compressed air generator 9 and a gun 8 to spray a stream of compressed air. The gun can spray the stream of compressed air in a direction generally parallel to the seat axis 42 and therefore parallel to the longitudinal axis of the strip 60. The gun can be located on one side of the roller 4 and can be stationary, i.e., the gun does not rotate with the roller. In this way, a single compressed air system can be used for all seats 41. During rotation, as the strip passes in front of the gun 8, the compressed air stream pushes the strip 60 into the coil 51, and the aforementioned measurement can be performed using the inductive sensor 5. This is in Figure 5 The figure shows a series of “screenshots” taken at consecutive time intervals. At the far left of the figure, the strip 60 is inserted into the seat 41. During the subsequent rotation, the seat with the strip 60 passes in front of the gun 8, and compressed air is ejected through the gun 8 in direction 83. The strip 60 is then pushed into the coil 51 (see the following snapshot from left to right of the figure up to the dashed line 64).

[0232] Dashed line 84 Figure 5 It is divided into two parts. Figure 5 The second part to the right of the dashed line 84 is several time intervals later than the left part (see details below).

[0233] The inspection devices 100 and 200 of the present invention may further include a rejection device (in Figure 5The right-hand portion (schematically depicted as a rectangle 82) of the rejection device is adapted to reject strip articles 60 that do not have receptors 12 or have receptors 12 with undesirable characteristics. As previously explained, strip articles 60 can be advantageously rejected based on signals emitted by inductive sensors 5, according to calculations or determinations performed by control unit 7. Figure 5 As shown in the right-hand portion, for example, the effect of the rejection device 82 is to retain the defective strip 60 in the roller 4, while the valid strip 60 is transferred to other rollers (not shown) for further processing.

[0234] like Figure 9 As depicted, the strip-shaped article 600 may further include a first receptor 12 and a second receptor 121. The strip-shaped article 600 generally includes, according to... Figure 1 and Figure 2 Two strip-shaped articles 60 in an embodiment.

[0235] In cases where the strip-shaped article 600 includes more than one sensor, it is preferable to provide an inspection device according to the third embodiment as... Figure 10 Inspection device 300.

[0236] The inspection device 300 includes two or more inspection rollers 4: at least a first roller and a second roller, each of which includes a coil 51. The first or second roller is identical to the roller 4, and the rollers can be configured according to... Figure 3 as well as Figure 13-14 The roller described in the first embodiment or according to Figure 4 or Figure 5 The roller described in the second embodiment. However, the roller is preferably of the same type, that is, the roller described in the first embodiment of the inspection device 100 or the roller described in the second embodiment of the inspection device 200.

[0237] The first roller 4 is adapted to inspect the first sensor 12 of the strip-shaped product 600, while the second roller 4 is adapted to inspect the second sensor 121 of the strip-shaped product 600. For example, if the first roller and the second roller are according to... Figure 4 and Figure 5 In the second embodiment of the roller, the compressed air system is located at the first side surface of the first roller in the first roller, and at the second side surface of the second roller in the second roller.

[0238] like Figure 11 and Figure 12As depicted, after the first sensor 12 is inspected, the strip article 600 is transferred from the first roller to the second roller. The first roller and the second roller are substantially tangent to each other. The gap between the first roller and the second roller allows the strip article 600 to be inserted therebetween. The transfer takes place between the seat of the first roller and the seat of the second roller.

[0239] exist Figure 11 In the middle, it is shown that according to Figure 3 , Figure 13 , Figure 14 The transfer between the two rollers 4 in the first embodiment. Figure 12 In the middle, it is shown that according to Figure 4 , Figure 5 The transfer between the two rollers 4 in the second embodiment.

[0240] For the purposes of this specification and the appended claims, unless otherwise indicated, all figures representing quantities, quantities, percentages, etc., shall be understood to be modified by the term "about" in all cases. Furthermore, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically listed herein. Thus, in this context, the number A is understood to be A ± 10% A. In this context, the number A can be considered to include a value within the general standard error for the measurement of the attribute represented by the number A. In some instances as used in the appended claims, the number A may deviate from the percentages listed above, provided that the amount of deviation from A does not significantly affect one or more fundamental and novel features of the claimed invention. Furthermore, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically listed herein.

Claims

1. A method of inspecting a rod article, the method comprising: o providing a first drum having a plurality of seats; o providing an induction sensor comprising a coil for at least one of the plurality of seats of the first drum; o providing a rod article comprising a first susceptor comprising an electrically conductive material for at least one of the plurality of seats of the first drum; o inserting the rod article into the coil of the induction sensor; o detecting a maximum or a minimum of a parametric function of impedance of the coil during insertion of the rod article; o discarding the rod article based on the maximum or the minimum of the parametric function of impedance.

2. The method according to claim 1, comprising: o comparing the maximum or the minimum of the parametric function of impedance to a threshold value; o discarding the rod article based on the comparison.

3. The method according to claim 1 or 2, comprising: o measuring a length of the first susceptor based on the maximum or the minimum of the parametric function of impedance of the coil during insertion of the rod article.

4. The method according to claim 1 or 2, comprising: o measuring a parametric function of variation over time of impedance of the coil during insertion of the rod article.

5. The method according to claim 4, comprising: o measuring a length of the first susceptor based on a curve defined by the parametric function of variation over time of impedance of the coil during insertion of the rod article into the coil.

6. The method of claim 1 or 2, wherein, The first susceptor has a nominal length, and the step of providing an induction sensor comprising a coil for at least one of the plurality of seats of the first drum comprises: o providing an induction sensor comprising a coil having a length longer than the nominal length of the first susceptor for at least one of the plurality of seats of the first drum.

7. The method of claim 1 or 2, wherein, The rod article has a longitudinal axis and the first drum has a rotation axis, and wherein the step of providing a rod article comprising a first susceptor for the at least one of the plurality of seats of the first drum comprises: o providing a rod article having a longitudinal axis substantially parallel to the rotation axis for at least one of the plurality of seats of the first drum.

8. The method of claim 1 or 2, wherein, The rod article has a first end and a second end and the first susceptor is located at the first end of the rod article, and wherein the step of inserting the rod article into the coil of the induction sensor comprises: o inserting the rod article into the coil of the induction sensor so that the first end of the rod article is located within the coil.

9. The method of claim 1 or 2, wherein, The step of discarding the rod article based on the maximum or the minimum of the parametric function of impedance comprises: - discarding the rod article if the maximum or the minimum of the parametric function of impedance is outside a pre-set range.

10. The method of inspecting a strip article of claim 1 or 2, wherein, The rod article has a first end and a second end and a second susceptor, the first susceptor being located at the first end of the rod article and the second susceptor being located at the second end of the rod article, and wherein the method comprises: o discarding the rod article if the maximum or the minimum of the parametric function of impedance is outside a pre-set range. o providing a second drum having a plurality of seats; o providing at least one seat of the plurality of seats of the second drum with an inductive sensor comprising a coil; o transferring the rod article from the first drum to the second drum so that the rod article is housed in at least one seat of the plurality of seats of the second drum; o inserting the rod article into the coil of the inductive sensor of the second drum so that the second end of the rod article is inside the coil; o detecting a maximum or a minimum of a parametric function of the impedance of the coil during the insertion of the rod article; o discarding the rod article based on the maximum or the minimum of the parametric function of the impedance.

11. The method of claim 1 or 2, wherein, The step of inserting the rod article into the coil of the inductive sensor comprises: o sliding the rod article on a bottom surface of the seat so as to insert the rod article into the coil.

12. The method of claim 11, wherein, The step of sliding the rod article on a bottom surface of the seat so as to insert the rod article into the coil comprises: o pushing the rod article inside the coil by means of an air flow.

13. The method of claim 1 or 2, wherein, The coil comprises a first half-coil and a second half-coil, the first half-coil and the second half-coil being movable from a first operating position, in which the first half-coil and the second half-coil are in contact with each other, thereby forming the coil in which an electric current can flow, to a second operating position, in which the first half-coil and the second half-coil are separated from each other and no electric current can flow, and vice versa, wherein the step of inserting the rod article into the coil of the inductive sensor comprises: o moving the first half-coil and the second half-coil from the second operating position to the first operating position.

14. The method according to the preceding claim 10, comprising the step of: o calibrating the inductive sensor using a rod article comprising a first susceptor or a second susceptor or both having a length equal to a nominal length.

15. The method according to the preceding claim 1 or 2, wherein, The rod article comprises a component of an aerosol-generating article.

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