Aerosol-generating article comprising classification

Abstract

An aerosol-generating article (100) for use with an aerosol-generating device (400) to generate an aerosol comprises an aerosol-generating substrate is provided. The aerosol-generating article (100) further comprises at least one wrapper (103) defining the longitudinal surface of the aerosol- generating article (100) extending between an upstream end (101) of the aerosol-generating article (100) and a downstream end (102) of the aerosol-generating article (100). The longitudinal surface defines a generally cylindrical shape. A classification region (105) is provided on the at least one wrapper (103). The classification region comprises a second identifier readable by a sensor of an aerosol-generating device (400). The at least one wrapper (103) comprises a tipping paper (311) and a cigarette paper (310), the tipping paper (311) extending to the downstream end of the aerosol-generating article (100), and the cigarette paper (310) extending to the upstream end of the aerosol-generating article (100), the cigarette paper (310) circumscribing the aerosol- generating substrate. The classification region (105) is provided on the tipping paper (311).

Description

[0001] AEROSOL-GENERATING ARTICLE COMPRISING CLASSIFICATION

[0002] The present invention relates to an aerosol-generating article for use with an aerosolgenerating device to generate an aerosol. In particular, the present invention relates to an aerosol-generating article for use with an aerosol-generating device, the aerosol-generating article comprising a classification region. The present invention also relates to an aerosolgenerating device, and to an aerosol-generating system comprising the aerosol-generating article and the aerosol-generating device.

[0003] Aerosol-generating articles in which an aerosol-generating substrate, such as a tobaccocontaining substrate, is heated rather than combusted, are known in the art. Typically, in such heated smoking articles an aerosol is generated by the transfer of heat from a heat source to a physically separate aerosol-generating substrate or material, which may be located in contact with, within, around, or downstream of the heat source. During use of the aerosol-generating article, volatile compounds are released from the aerosol-generating substrate by heat transfer from the heat source and are entrained in air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol.

[0004] A number of prior art documents disclose aerosol-generating devices for consuming aerosol-generating articles. Such devices include, for example, electrically heated aerosolgenerating devices in which an aerosol is generated by the transfer of heat from one or more electrical heater elements of the aerosol-generating device to the aerosol-generating substrate of a heated aerosol-generating article. Aerosol-generating devices of the prior art may include a cavity for at least partially receiving an aerosol-generating article.

[0005] Specific aerosol-generating devices may be configured for use with specific aerosolgenerating articles. For example, the temperature reached by the one or more electrical heater elements of an aerosol-generating device may be configured to maximise aerosol generation in specific aerosol-generating substrates without leading the generation of unpleasant flavours.

[0006] However, it is conceivable that a user may, inadvertently or otherwise, attempt to use an aerosol-generating article with an aerosol-generating device where the device is not designed to be used with the article. For example, a user may attempt to use a conventional combustible cigarette, or a counterfeit aerosol-generating article in an aerosol-generating device. This may result in poor aerosol-generation and reduced user experience which may reflect badly on the aerosol-generating device. Moreover, the conventional combustible or the counterfeit aerosolgenerating article may contain materials which may release harmful aerosols or decomposition products when they are heated according to the heating profile of an aerosol-generating device. In addition, the use of aerosol-generating articles other than those intended may damage the aerosol-generating device. Furthermore, it may be desirable for the one or more electrical heater elements of an aerosol-generating device to reach different temperatures at different times (i.e. have a different heating profile) depending on the variety or flavour of aerosol-generating article used with the aerosol-generating device. Where this is the case, it would be desirable for the aerosolgenerating device to be able to alter the temperature settings automatically without a user needing to enter any details manually.

[0007] Accordingly, it would be desirable to provide a system in which an aerosol-generating device is able to detect the presence of particular aerosol-generating articles. Where the aerosolgenerating device does not recognise a particular aerosol-generating article, the aerosolgenerating device may not activate the heater element to prevent a poor user experience. In addition, where the aerosol-generating device detects a particular recognised aerosol-generating article, it may run a particular heating profile configured specifically for use with that variety of aerosol-generating article.

[0008] In addition, it would be desirable to provide a system in which a large number of compatible aerosol-generating articles may be distinguished by the aerosol-generating device.

[0009] In addition, it would be desirable to provide a system in which an aerosol-generating device is able to detect the presence of a particular aerosol-generating articles reliably and even after several uses of the aerosol-generating system.

[0010] According to a first aspect of the present disclosure, there is provided an aerosolgenerating article for use with an aerosol-generating device to generate an aerosol. The aerosolgenerating article may comprise an aerosol-generating substrate. The aerosol-generating article may comprise at least one wrapper defining the longitudinal surface of the aerosol-generating article. The at least one wrapper may extend between an upstream end of the aerosol-generating article and a downstream end of the aerosol-generating article. The longitudinal surface may define a generally cylindrical shape. The aerosol-generating article may comprise a classification region provided on the at least one wrapper, the classification region may comprise an identifier readable by a sensor of an aerosol-generating device.

[0011] According to a first aspect of the present invention, there is provided an aerosol-generating article for use with an aerosol-generating device to generate an aerosol. The aerosol-generating article comprises an aerosol-generating substrate. The aerosol-generating article comprises at least one wrapper defining the longitudinal surface of the aerosol-generating article extending between an upstream end of the aerosol-generating article and a downstream end of the aerosolgenerating article. The longitudinal surface defines a generally cylindrical shape. The aerosolgenerating article comprises a classification region provided on the at least one wrapper, the classification region comprising an identifier readable by a sensor of an aerosol-generating device. In use, when an aerosol-generating article is used in combination with an appropriate aerosol-generating device, the identifier may be detected by a sensor of the aerosol-generating device. As described in more detail below, the identifier may be configured such that a variety of different authentic aerosol-generating articles may be distinguished by the aerosol-generating device. By distinguishing between a variety of different authentic aerosol-generating articles, the aerosol-generating device may be configured to activate differently when different aerosolgenerating articles are detected using the second identifier. For example, the aerosol-generating device may be configured to activate a specific heating profile which is tailored to optimise aerosol generation from specific aerosol-generating articles. The identifier may be referred to as the classification identifier.

[0012] The longitudinal surface of the aerosol-generating article defines a generally cylindrical shape. Preferably, the longitudinal surface of the aerosol-generating article defines a cylinder.

[0013] As used herein, the term “longitudinal” refers to the direction corresponding to the main longitudinal axis of the aerosol-generating article, which extends between the upstream and downstream ends of the aerosol-generating article or aerosol-generating device. As used herein, the terms “upstream” and “downstream” describe the relative positions of elements, or portions of elements, of the aerosol-generating article in relation to the direction in which the aerosol is transported through the aerosol-generating article or aerosol-generating device during use. During use, air is drawn through the aerosol-generating article in the longitudinal direction.

[0014] As used herein, the term “length” denotes the dimension of a component of the aerosolgenerating article in the longitudinal direction, from the component’s furthest upstream point to the component’s furthest downstream point. For example, it may be used to denote the dimension of the authentication region or the classification region from the furthest upstream point of the regions to the furthest downstream point of the region in the longitudinal direction.

[0015] The aerosol-generating article may further comprise an authentication region provided on the at least one wrapper, the authentication region comprising an authentication identifier readable by a sensor of an aerosol-generating device. The authentication identifier may be different from the classification identifier. Although the present of an authentication region is described in detail below, it will be understood that this feature is optional and is not an essential feature of the invention.

[0016] The classification region may be provided as a band at least partially circumscribing the longitudinal surface of the aerosol-generating article, the classification region extending longitudinally between an upstream end and a downstream end.

[0017] The authentication region is provided as a band at least partially circumscribing the longitudinal surface of the aerosol-generating article, the authentication region extending longitudinally between an upstream end and a downstream end. The provision that the classification or authentication regions are provided as a band at least partially circumscribing the longitudinal surface of the aerosol-generating article may advantageously mean that the classification and authentication identifiers may be readable by the appropriate sensors of an aerosol-generating device regardless of the rotational orientation of the aerosol-generating article about the longitudinal axis. This may advantageously make the authentication and classification of the aerosol-generating article more reliable.

[0018] As used herein, the term “at least partially circumscribing” means that the classification region or the authentication region may be provided as a band which extends around at least a portion of the circumference of the longitudinal surface of the aerosol-generating article. The classification region or the authentication region may be provided as a band which includes at least one break in it such that the band does not fully circumscribe the longitudinal surface of the aerosol-generating article.

[0019] Where the band does not fully circumscribe the longitudinal surface of the aerosolgenerating article, the band may include any number of breaks between adjacent portions of the band. For example, the band may comprise at least 2, at least 3, at least 5, or at least 10 breaks between adjacent portions of the band.

[0020] The classification region may be provided as a band which circumscribes at least 50 percent of the circumference of the longitudinal surface of the aerosol-generating article between the upstream end of the classification region and the downstream end of the classification region. To be clear, this does not mean that the classification region accounts for at least 50 percent of the entire longitudinal surface of the aerosol-generating article. This means that in the region between the upstream end of the classification region and the downstream end of the classification region, the band of the classification region extends along the circumferential surface between an angle of at least 180 degrees. Where the band comprises more than one break, the sum of the angles of all the portions of the band is at least 180 degrees.

[0021] The classification region may be provided as a band which circumscribes at least 60 percent, at least 70 percent, at least 80 percent, at least 90 percent, or at least 95 percent of the circumference of the longitudinal surface of the aerosol-generating article between the upstream end of the classification region and the downstream end of the classification region. The classification region may be provided as a band which fully circumscribes the longitudinal surface of the aerosol-generating article between the upstream end of the classification region and the downstream end of the classification region.

[0022] The authentication region may be provided as a band which circumscribes at least 50 percent of the circumference of the longitudinal surface of the aerosol-generating article between the upstream end of the authentication region and the downstream end of the authentication region. For example, the authentication region may be provided as a band which circumscribes at least 60 percent, at least 70 percent, at least 80 percent, at least 90 percent, or at least 95 percent of the circumference of the longitudinal surface of the aerosol-generating article between the upstream end of the authentication region and the downstream end of the authentication region. The authentication region may be provided as a band which fully circumscribes the longitudinal surface of the aerosol-generating article between the upstream end of the authentication region and the downstream end of the authentication region.

[0023] The classification region may not overlay the aerosol-generating substrate. The authentication region may not overlay the aerosol-generating substrate.

[0024] As used herein, the term ‘overlay’ means that a first feature occupies the same longitudinal and circumferential position in the aerosol-generating article as a second feature, separated only by a radial displacement.

[0025] Since the aerosol-generating substrate will be heated during use to generate an aerosol, the provision that the classification or authentication regions do not overlay the aerosol-generating substrate may mean that the classification or authentication regions are distant from the region of the aerosol-generating article which is heated during use. This may advantageously help to prevent the classification or authentication identifiers from being damaged by the heat during use. In addition, this may also mean that the sensor or sensors in the aerosol-generating device to be used with the aerosol-generating article can be located far from the region of the aerosolgenerating device which is heated during use. This may advantageously help to prevent the sensor or sensors from being damaged by the heat during use. This may also prevent the need for the sensor or sensors to be located in the same space as the heating apparatus of the aerosolgenerating device.

[0026] The authentication region may have any length between the upstream end of the authentication region and the downstream end of the authentication region.

[0027] The authentication region may have a length between the upstream end of the authentication region and the downstream end of the authentication region of at least 1 millimetre, preferably at least 1.5 millimetres, more preferably at least 2 millimetres, still more preferably at least 2.5 millimetres, still more preferably at least 3 millimetres.

[0028] The authentication region may extend the full length of the aerosol-generating article. The authentication region may have a length between the upstream end of the authentication region and the downstream end of the authentication region of no more than 6 millimetres, preferably no more than 5.5 millimetres, more preferably no more than 5 millimetres, still more preferably no more than 4.5 millimetres, still more preferably no more than 4 millimetres.

[0029] The authentication region may have a length between the upstream end of the authentication region and the downstream end of the authentication region of between 1 millimetre and 6 millimetres, preferably between 1.5 millimetres and 5.5 millimetres, more preferably between 2 millimetres and 5 millimetres, still more preferably between 2.5 millimetres and 4.5 millimetres, still more preferably between 3 millimetres and 4 millimetres. The authentication region may have a length between the upstream end of the authentication region and the downstream end of the authentication region of about 3.5 millimetres.

[0030] The provision of an authentication region having a length within the range set out above may provide an optimum balance between providing a sufficient size authentication region for the sensor of an aerosol-generating device to reliably detect the presence of the authentication identifier without the need to provide too much authentication identifier.

[0031] The authentication region may have a length which is greater than or equal to the field of view of the sensor of the corresponding aerosol-generating device. In this way, the authentication region may be reliably read by the sensor.

[0032] As used herein, the term “field of view” refers to the maximum length in the longitudinal direction within which a sensor is able to detect the classification identifier or the authentication identifier.

[0033] The upstream end of the authentication region may be any distance from the upstream end of the aerosol-generating article.

[0034] The upstream end of the authentication region may be at least 15 millimetres from the upstream end of the aerosol-generating article, preferably at least 18 millimetres from the upstream end of the aerosol-generating article, more preferably at least 21 millimetres from the upstream end of the aerosol-generating article.

[0035] The upstream end of the authentication region may be no more than 35 millimetres from the upstream end of the aerosol-generating article, preferably no more than 30 millimetres from the upstream end of the aerosol-generating article, more preferably no more than 26 millimetres from the upstream end of the aerosol-generating article.

[0036] The upstream end of the authentication region may be between 15 millimetres and 35 millimetres from the upstream end of the aerosol-generating article, preferably between 18 millimetres and 30 millimetres from the upstream end of the aerosol-generating article, more preferably between 21 millimetres and 26 millimetres from the upstream end of the aerosolgenerating article.

[0037] The upstream end of the authentication region may be about 22 millimetres from the upstream end of the aerosol-generating article.

[0038] Spacing the upstream end of the authentication region from the upstream end of the aerosol-generating article may advantageously keep the authentication region away from the region of the aerosol-generating article which is heated in use. As described above, this may advantageously help to prevent the authentication identifier from being damaged by the heat during use. In turn, this may advantageously provide a more reliable means for authenticating the aerosol-generating article. The upstream end of the authentication region may be any distance from the downstream end of the aerosol-generating article.

[0039] The upstream end of the authentication region may be at least 19 millimetres from the downstream end of the aerosol-generating article, preferably at least 20 millimetres from the downstream end of the aerosol-generating article, more preferably at least 22 millimetres from the downstream end of the aerosol-generating article.

[0040] The upstream end of the authentication region may be no more than 26 millimetres from the downstream end of the aerosol-generating article, preferably no more than 25 millimetres from the downstream end of the aerosol-generating article, more preferably no more than 24 millimetres from the downstream end of the aerosol-generating article.

[0041] The upstream end of the authentication region may be between 19 millimetres and 26 millimetres from the downstream end of the aerosol-generating article, preferably between 20 millimetres and 25 millimetres from the downstream end of the aerosol-generating article, more preferably between 22 millimetres and 24 millimetres from the downstream end of the aerosolgenerating article.

[0042] The upstream end of the authentication region may be about 23 millimetres from the downstream end of the aerosol-generating article.

[0043] The downstream end of the authentication region may be any distance from the downstream end of the aerosol-generating article.

[0044] The downstream end of the authentication region may be at least 17 millimetres from the downstream end of the aerosol-generating article, preferably at least 18.5 millimetres from the downstream end of the aerosol-generating article, more preferably at least 19 millimetres from the downstream end of the aerosol-generating article.

[0045] The downstream end of the authentication region may be no more than 24 millimetres from the downstream end of the aerosol-generating article, preferably no more than 22 millimetres from the downstream end of the aerosol-generating article, more preferably no more than 20 millimetres from the downstream end of the aerosol-generating article.

[0046] The downstream end of the authentication region may be between 17 millimetres and 24 millimetres from the downstream end of the aerosol-generating article, preferably between 18.5 millimetres and 22 millimetres from the downstream end of the aerosol-generating article, more preferably between 19 millimetres and 20 millimetres from the downstream end of the aerosolgenerating article.

[0047] The downstream end of the authentication region may be about 19.5 millimetres from the downstream end of the aerosol-generating article.

[0048] Spacing the downstream end of the authentication region from the downstream end of the aerosol-generating article may advantageously ensure that the authentication region is not covered by a user’s mouth during use since the downstream end of the aerosol-generating article may be received in the oral cavity of a user in use. In addition, spacing the downstream end of the authentication region from the downstream end of the aerosol-generating article may ensure that the authentication region is received in a recess of an aerosol-generating article in use. This may advantageously ensure that the sensor of the aerosol-generating device is able to detect the authentication identifier in use.

[0049] The downstream end of the authentication region may be any distance from the upstream end of the aerosol-generating article.

[0050] The downstream end of the authentication region may be at least 20 millimetres from the upstream end of the aerosol-generating article, preferably at least 22 millimetres from the upstream end of the aerosol-generating article, more preferably at least 25 millimetres from the upstream end of the aerosol-generating article.

[0051] The downstream end of the authentication region may be no more than 30 millimetres from the upstream end of the aerosol-generating article, preferably no more than 28 millimetres from the upstream end of the aerosol-generating article, more preferably no more than 26 millimetres from the upstream end of the aerosol-generating article.

[0052] The downstream end of the authentication region may be between 20 millimetres and 30 millimetres from the upstream end of the aerosol-generating article, preferably between 22 millimetres and 28 millimetres from the upstream end of the aerosol-generating article, more preferably between 25 millimetres and 26 millimetres from the upstream end of the aerosolgenerating article.

[0053] The downstream end of the authentication region may be about 25.5 millimetres from the upstream end of the aerosol-generating article.

[0054] The classification region may have any length between the upstream end of the classification region and the downstream end of the classification region.

[0055] The classification region may have a length between the upstream end of the classification region and the downstream end of the classification region of at least 0.5 millimetres, preferably at least 1 millimetre, more preferably at least 1.5 millimetres, still more preferably at least 2 millimetres.

[0056] The classification region may have a length between the upstream end of the classification region and the downstream end of the classification region of no more than 5 millimetres, preferably no more than 4.5 millimetres, more preferably no more than 4 millimetres, still more preferably no more than 3 millimetres.

[0057] The classification region may have a length between the upstream end of the classification region and the downstream end of the classification region of between 0.5 millimetres and 5 millimetres, preferably between 1 millimetre and 4.5 millimetres, more preferably between 1.5 millimetres and 4 millimetres, still more preferably between 2 millimetres and 3 millimetres. The classification region may have a length between the upstream end of the classification region and the downstream end of the classification region of about 2.8 millimetres.

[0058] The provision of a classification region having a length within the range set out above may provide an optimum balance between providing a sufficient size classification region for the sensor of an aerosol-generating device to reliably detect the presence of the second identifier without the need to provide too much second identifier.

[0059] The classification region may have a length which is greater than or equal to the field of view of the sensor of the corresponding aerosol-generating device. In this way, the classification region may be reliably read by the sensor.

[0060] The upstream end of the classification region may be any distance from the upstream end of the aerosol-generating article.

[0061] The upstream end of the classification region may be at least 15 millimetres from the upstream end of the aerosol-generating article, preferably at least 17 millimetres from the upstream end of the aerosol-generating article, more preferably at least 19 millimetres from the upstream end of the aerosol-generating article.

[0062] The upstream end of the classification region may be no more than 24 millimetres from the upstream end of the aerosol-generating article, preferably no more than 22 millimetres from the upstream end of the aerosol-generating article, more preferably no more than 20 millimetres from the upstream end of the aerosol-generating article.

[0063] The upstream end of the classification region may be between 15 millimetres and 24 millimetres from the upstream end of the aerosol-generating article, preferably between 17 millimetres and 22 millimetres from the upstream end of the aerosol-generating article, more preferably between 19 millimetres and 20 millimetres from the upstream end of the aerosolgenerating article.

[0064] The upstream end of the classification region may be about 19.5 millimetres from the upstream end of the aerosol-generating article.

[0065] Spacing the upstream end of the classification region from the upstream end of the aerosol-generating article may advantageously keep the classification region away from the region of the aerosol-generating article which is heated in use. As described above, this may advantageously help to prevent the second identifier from being damaged by the heat during use. In turn, this may advantageously provide a more reliable means for classifying the aerosolgenerating article.

[0066] The upstream end of the classification region may be any distance from the downstream end of the aerosol-generating article.

[0067] The upstream end of the classification region may be at least 20 millimetres from the downstream end of the aerosol-generating article, preferably at least 22 millimetres from the downstream end of the aerosol-generating article, more preferably at least 25 millimetres from the downstream end of the aerosol-generating article.

[0068] The upstream end of the classification region may be no more than 30 millimetres from the downstream end of the aerosol-generating article, preferably no more than 28 millimetres from the downstream end of the aerosol-generating article, more preferably no more than 26 millimetres from the downstream end of the aerosol-generating article.

[0069] The upstream end of the classification region may be between 20 millimetres and 30 millimetres from the downstream end of the aerosol-generating article, preferably between 22 millimetres and 28 millimetres from the downstream end of the aerosol-generating article, more preferably between 25 millimetres and 26 millimetres from the downstream end of the aerosolgenerating article.

[0070] The upstream end of the authentication region may be about 25.5 millimetres from the downstream end of the aerosol-generating article.

[0071] The downstream end of the classification region may be any distance from the downstream end of the aerosol-generating article.

[0072] The downstream end of the classification region may be at least 15 millimetres from the downstream end of the aerosol-generating article, preferably at least 20 millimetres from the downstream end of the aerosol-generating article, more preferably at least 22 millimetres from the downstream end of the aerosol-generating article.

[0073] The downstream end of the classification region may be no more than 30 millimetres from the downstream end of the aerosol-generating article, preferably no more than 25 millimetres from the downstream end of the aerosol-generating article, more preferably no more than 23 millimetres from the downstream end of the aerosol-generating article.

[0074] The downstream end of the classification region may be between 15 millimetres and 30 millimetres from the downstream end of the aerosol-generating article, preferably between 20 millimetres and 25 millimetres from the downstream end of the aerosol-generating article, more preferably between 22 millimetres and 23 millimetres from the downstream end of the aerosolgenerating article.

[0075] The downstream end of the classification region may be about 22.7 millimetres from the downstream end of the aerosol-generating article.

[0076] Spacing the downstream end of the classification region from the downstream end of the aerosol-generating article may advantageously ensure that the classification region is not covered by a user’s mouth during use since the downstream end of the aerosol-generating article may be received in the oral cavity of a user in use. In addition, spacing the downstream end of the classification region from the downstream end of the aerosol-generating article may ensure that the classification region is received in a recess of an aerosol-generating article in use. This may advantageously ensure that the sensor of the aerosol-generating device is able to detect the second identifier in use.

[0077] The downstream end of the classification region may be any distance from the upstream end of the aerosol-generating article.

[0078] The downstream end of the classification region may be at least 18 millimetres from the upstream end of the aerosol-generating article, preferably at least 20 millimetres from the upstream end of the aerosol-generating article, more preferably at least 22 millimetres from the upstream end of the aerosol-generating article.

[0079] The downstream end of the classification region may be no more than 28 millimetres from the upstream end of the aerosol-generating article, preferably no more than 25 millimetres from the upstream end of the aerosol-generating article, more preferably no more than 23 millimetres from the upstream end of the aerosol-generating article.

[0080] The downstream end of the classification region may be between 18 millimetres and 28 millimetres from the upstream end of the aerosol-generating article, preferably between 20 millimetres and 25 millimetres from the upstream end of the aerosol-generating article, more preferably between 22 millimetres and 23 millimetres from the upstream end of the aerosolgenerating article.

[0081] The downstream end of the classification region may be about 22.3 millimetres from the upstream end of the aerosol-generating article.

[0082] The aerosol-generating article may have any total length between the upstream end of the aerosol-generating article and the downstream end of the aerosol-generating article.

[0083] The aerosol-generating article may have a total length between the upstream end of the aerosol-generating article and the downstream end of the aerosol-generating article of at least 30 millimetres, preferably at least 35 millimetres, more preferably at least 40 millimetres.

[0084] The aerosol-generating article may have a total length between the upstream end of the aerosol-generating article and the downstream end of the aerosol-generating article of no more than 60 millimetres, preferably no more than 55 millimetres, more preferably no more than 50 millimetres.

[0085] The aerosol-generating article may have a total length between the upstream end of the aerosol-generating article and the downstream end of the aerosol-generating article of between 30 millimetres and 60 millimetres, preferably between 35 millimetres and 55 millimetres, more preferably between 40 millimetres and 50 millimetres.

[0086] The aerosol-generating article may have a total length between the upstream end of the aerosol-generating article and the downstream end of the aerosol-generating article of about 45 millimetres.

[0087] The aerosol-generating article may have any external diameter. The aerosol-generating article may have an external diameter of between 4.5 millimetres and 17 millimetres, preferably between 6 millimetres and 9 millimetres. The aerosol-generating article may have an external diameter of about 7 millimetres. The aerosol-generating article may have an external diameter of about 7.23 millimetres.

[0088] The authentication region may be entirely downstream of the classification region. In other words, there may be no overlap between the authentication region and the classification region. This may advantageously make it easier for the sensor or sensors of an aerosol-generating device to reliably detect both the classification identifier and the authentication identifier. In addition, where one of the classification identifier or the authentication identifier is identified by a sensor before the other of the classification identifier and the authentication identifier, providing one upstream of the other may allow both to be identified by the same sensor.

[0089] The upstream end of the authentication region may be further upstream than the downstream end of the classification region such that the authentication region and the classification region at least partially overlap.

[0090] The provision of an overlap between the authentication region and the classification region may advantageously reduce the amount of space on the wrapper dedicated to authentication and classification. This may allow more space for other information such as branding.

[0091] The authentication identifier may be provided on the inner surface of the at least one wrapper.

[0092] The provision that the authentication identifier is on the inner surface of the at least one wrapper may advantageously hide the authentication identifier form a user. This may advantageously make it more less obvious that an authentication region exists at all. This in turn may advantageously make authentic aerosol-generating articles harder to forge or counterfeit. In addition, providing the authentication identifier on the inner surface of the at least one wrapper may advantageously reduce the amount of space on the outer surface of the wrapper dedicated to authentication and classification.

[0093] The authentication identifier may be printed on the inner surface of the at least one wrapper.

[0094] The authentication identifier may comprise at least one taggant.

[0095] As used herein, the term “taggant” refers to a chemical or physical marker added to a component, the presence of which may be detected by a suitable detector enabling the component to be identified. Physical taggants can take many different forms but are typically microscopic in size, included at low levels, and simple to detect. The taggant may comprise uniquely encoded material.

[0096] The authentication identifier may comprise a plurality of different taggants. The provision of a plurality of different taggants may make the authentication means more secure since the authentication region may be more difficult to replicate in a counterfeit article.

[0097] The authentication identifier may comprise no more than 6 different taggants. The authentication identifier may comprise about 3 different taggants.

[0098] The taggant may be a photoluminescent material having a known emission half-life. A taggant comprising a photoluminescent material may be more difficult to copy during the production of counterfeit aerosol-generating articles when compared to known systems comprising identifiable ink patterns. For example, it may be impossible to produce a counterfeit article without determining at least one of the particular photoluminescent material, one or more wavelengths of radiation at which the photoluminescent material may be excited, and one or more wavelengths at which the photoluminescent material may emit radiation.

[0099] The at least one taggant may comprise a taggant comprising a photoluminescent material having an emission half-life of between 10 microseconds and 2000 microseconds after photoexcitation of the photoluminescent material.

[0100] The at least one taggant may comprise a taggant comprising a photoluminescent material having an emission half-life of between 50 microseconds and 1000 microseconds after photoexcitation of the photoluminescent material.

[0101] As used herein, the term “emission half-life” refers to the time taken for an intensity of radiation emission by the photoluminescent material to decay by half after the photoluminescent material has been irradiated by a source of radiation and after the source of radiation has been removed or switched off.

[0102] The photoluminescent material may have an emission half-life of between 100 microseconds and 800 microseconds, an emission half-life of between about 50 microseconds and about 1000 microseconds may be sufficiently long to facilitate consistent and accurate determination of the half-life by an aerosol-generating device. In embodiments in which the photoluminescent material exhibits photoluminescence at one or more infrared wavelengths, an emission half-life of between about 50 microseconds and about 1000 microseconds may be sufficiently long to distinguish the taggant from other material used in the aerosol-generating article that may emit infrared radiation for several milliseconds after exposure to an infrared source.

[0103] The photoluminescent material may have an emission half-life of at least about 60 microseconds. The photoluminescent material may have an emission half-life of at least about 70 microseconds. The photoluminescent material may have an emission half-life of at least about 80 microseconds. The photoluminescent material may have an emission half-life of at least about 90 microseconds. The photoluminescent material may have an emission half-life of at least about 100 microseconds. The photoluminescent material may have an emission half-life of at least about 110 microseconds. The photoluminescent material may have an emission half-life of at least about 120 microseconds. The photoluminescent material may have an emission half-life of at least about 130 microseconds. The photoluminescent material may have an emission half-life of at least about 140 microseconds. The photoluminescent material may have an emission half- life of at least about 150 microseconds. The photoluminescent material may have an emission half-life of at least about 160 microseconds. The photoluminescent material may have an emission half-life of at least about 170 microseconds. The photoluminescent material may have an emission half-life of at least about 180 microseconds. The photoluminescent material may have an emission half-life of at least about 190 microseconds. The photoluminescent material may have an emission half-life of at least about 200 microseconds.

[0104] The photoluminescent material may have an emission half-life of less than about 900 microseconds. The photoluminescent material may have an emission half-life of less than about 800 microseconds. The photoluminescent material may have an emission half-life of less than about 700 microseconds. The photoluminescent material may have an emission half-life of less than about 600 microseconds. The photoluminescent material may have an emission half-life of less than about 500 microseconds. The photoluminescent material may have an emission halflife of less than about 400 microseconds. The photoluminescent material may have an emission half-life of less than about 300 microseconds. The photoluminescent material may have an emission half-life of less than about 280 microseconds. The photoluminescent material may have an emission half-life of less than about 260 microseconds. The photoluminescent material may have an emission half-life of less than about 250 microseconds. The photoluminescent material may have an emission half-life of less than about 240 microseconds. The photoluminescent material may have an emission half-life of less than about 230 microseconds. The photoluminescent material may have an emission half-life of less than about 220 microseconds. The photoluminescent material may have an emission half-life of less than about 210 microseconds. The photoluminescent material may have an emission half-life of less than about 200 microseconds.

[0105] The photoluminescent material may have an emission half-life of between about 100 microseconds and about 800 microseconds. The photoluminescent material may have an emission half-life of between about 100 microseconds and about 500 microseconds. The photoluminescent material may have an emission half-life of between about 100 microseconds and about 300 microseconds. The photoluminescent material may have an emission half-life of between about 120 microseconds and about 250 microseconds. The photoluminescent material may have an emission half-life of between about 160 microseconds and about 200 microseconds.

[0106] Preferably, the photoluminescent material is excitable by infrared radiation.

[0107] Advantageously, infrared radiation may be more easily transmitted through materials used to form the aerosol-generating article compared to other wavelengths of radiation. For example, in embodiments in which the taggant is provided on an inner surface of a wrapper, infrared radiation may be transmitted through the wrapper to excite the photoluminescent material.

[0108] Advantageously, infrared radiation is relatively safe for user of the aerosol-generating article. The photoluminescent material may be excitable by infrared radiation within a wavelength range of between about 700 nanometres and about 1050 nanometres.

[0109] Preferably, the photoluminescent material exhibits photoluminescence in the infrared range. In other words, preferably the photoluminescent material emits infrared radiation. The photoluminescent material may exhibit photoluminescence across a range of wavelengths. Preferably, the photoluminescent material has a peak emission at a wavelength in the infrared range. The photoluminescent material may have a single peak emission. Preferably, the single peak emission occurs at a wavelength in the infrared range.

[0110] The photoluminescent material may exhibit photoluminescence within a wavelength range of between about 700 nanometres and about 1100 nanometres. The photoluminescent material may have a peak emission at a wavelength of between about 700 nanometres and about 1100 nanometres.

[0111] The photoluminescent material may exhibit photoluminescence within a wavelength range of between about 950 nanometres and about 1050 nanometres. The photoluminescent material may have a peak emission at a wavelength of between about 950 nanometres and about 1050 nanometres.

[0112] Preferably, the photoluminescent material comprises a phosphorescent material. The skilled person can select suitable materials based on an emission half-life, excitation wavelength and emission wavelength of the materials.

[0113] The at least one taggant may be visible to the naked eye. The at least one taggant may be nonvisible to the naked eye. The provision of a taggant which is nonvisible to the naked eye may advantageously make the presence of the authentication identifier harder to detect by a potential counterfeiter.

[0114] The authentication identifier may further comprise a visible component. The provision of an authentication identifier comprising a visible component may make tracking the location of the authentication identifier more straightforward during manufacture of the aerosol-generating article. For example, the authentication identifier may comprise a nonvisible taggant detectable by a sensor of an aerosol-generating device, and a visible ink to make the location of the authentication identifier clear during manufacture. For example, the authentication identifier may comprise a nonvisible taggant doped with a visible ink.

[0115] The classification identifier may be provided on the outer surface of the at least one wrapper.

[0116] The classification identifier may comprise at least one coloured band at least partially circumscribing the longitudinal surface of the aerosol-generating article. The classification identifier may comprise at least one coloured band fully circumscribing the longitudinal surface of the aerosol-generating article, the at least one coloured band having a consistent colour extending around the full circumference of the longitudinal surface. As used herein, the term “coloured band” refers to an area of the wrapper which at least partially circumscribes the aerosol-generating article, the area having a consistent colour. The area may have a different colour to the colour of the remainder of the wrapper which does not form part of the coloured band. The area may have the same colour to the colour of the remainder of the wrapper which does not form part of the coloured band. Where this is the case, the coloured band may comprise a portion of the wrapper which is devoid of any additional markings to ensure the entire coloured band has a consistent colour such that the same colour may be detected by a sensor of an aerosol-generating device regardless of the rotational orientation of the aerosolgenerating article about the longitudinal axis. This may advantageously make the authentication and classification of the aerosol-generating article more reliable.

[0117] The at least one coloured band may be printed on the outer surface of the at least one wrapper.

[0118] The at least one coloured band may be detectable by an optical sensor in an aerosolgenerating device. The at least one coloured band may be detectable by a colour sensor.

[0119] The at least one coloured band may have a length between an upstream end of the at least one coloured band and the downstream end of the at least one coloured band of at least 0.1 millimetres, preferably at least 0.25 millimetres, more preferably at least 0.5 millimetres.

[0120] The at least one coloured band may have a length between an upstream end of the at least one coloured band and the downstream end of the at least one coloured band of no more than 5 millimetres, preferably no mor than 3 millimetres, more preferably no more than 1 millimetre.

[0121] The at least one coloured band may have a length between an upstream end of the at least one coloured band and the downstream end of the at least one coloured band of between 0.1 millimetres and 5 millimetres, preferably between 0.25 millimetres and 3 millimetres, more preferably between 0.5 millimetres and 1 millimetre.

[0122] The at least one coloured band may have a length between an upstream end of the at least one coloured band of about 0.5 millimetres.

[0123] The at least one coloured band may have a length between an upstream end of the at least one coloured band of about 1 millimetre.

[0124] The provision of the at least one coloured band having this length may advantageously allow for reliable detection of the colour by a sensor of an aerosol-generating device. This may advantageously lead to more reliable classification of the aerosol-generating article.

[0125] The colour of the at least one coloured band may correspond to a specific type or class of aerosol-generating article. Once an aerosol-generating device identifies an aerosol-generating article, the aerosol-generating device may be configured to activate in a specific way. For example, the aerosol-generating device may be configured to activate a specific heating profile which is tailored to optimise aerosol generation from specific aerosol-generating articles. The classification identifier may comprise a plurality of coloured bands.

[0126] The provision of a plurality of coloured bands may advantageously allow for a greater number of different aerosol-generating articles, or classes of aerosol-generating articles, to be differentiated and classified by an aerosol-generating device. This is because a specific combination of coloured bands may correspond to a specific aerosol-generating article or class of aerosol-generating article.

[0127] The plurality of coloured bands may comprise two coloured bands, three coloured bands, or four coloured bands. The plurality of coloured bands may comprise only two coloured bands, only three coloured bands, or only four coloured bands.

[0128] The classification identifier may comprise a first coloured band having a first colour and a second coloured band having a second colour.

[0129] The first colour may be different to the second colour.

[0130] The first coloured band may be longer than the second coloured band.

[0131] The first coloured band may be entirely downstream of the second coloured band.

[0132] The first coloured band and the second coloured band may be separated by at least 0.1 millimetres, preferably at least 0.25 millimetres, more preferably at least 0.5 millimetres.

[0133] The first coloured band and the second coloured band may be separated by no more than 2 millimetres, preferably no more than 1.5 millimetres, more preferably no more than 1 millimetres.

[0134] The first coloured band and the second coloured band may be separated by between 0.1 millimetres and 2 millimetres, preferably between 0.25 millimetres and 1.5 millimetres, more preferably between 0.5 and 1 millimetre.

[0135] The first coloured band and the second coloured band may be separated by about 1 millimetre.

[0136] The first coloured band may have a length of about 1 millimetre.

[0137] The second coloured band may have a length of about 0.5 millimetres.

[0138] The first coloured band may be entirely downstream of the second coloured band.

[0139] The at least one wrapper may comprise a tipping paper and a cigarette paper, the tipping paper extending to the downstream end of the aerosol-generating article, and the cigarette paper extending to the upstream end of the aerosol-generating article, the cigarette paper circumscribing the aerosol-generating substrate.

[0140] The authentication region may be provided on the tipping paper.

[0141] The classification region may be provided on the tipping paper.

[0142] The upstream end of the tipping paper may be at least 15 millimetres from the downstream end of the aerosol-generating article, preferably at least 20 millimetres from the downstream end of the aerosol-generating article, more preferably at least 25 millimetres from the downstream end of the aerosol-generating article. The upstream end of the tipping paper may be no more than 35 millimetres from the downstream end of the aerosol-generating article, preferably no more than 30 millimetres from the downstream end of the aerosol-generating article, more preferably no more than 28 millimetres from the downstream end of the aerosol-generating article.

[0143] The upstream end of the tipping paper may be about 26 millimetres from the downstream end of the aerosol-generating article.

[0144] The upstream end of the classification region may be any distance from the upstream end of the tipping paper. The upstream end of the classification region may be any distance downstream from the upstream end of the tipping paper.

[0145] The upstream end of the classification region may be at least 0.1 millimetres, at least 0.3 millimetres, at least 0.5 millimetres, or at least 0.6 millimetres downstream from the upstream end of the tipping paper.

[0146] The upstream end of the classification region may be no more than 2 millimetres, no more than 1.5 millimetres, no more than 1.2 millimetres, or at least 1 millimetre downstream from the upstream end of the tipping paper.

[0147] The upstream end of the classification region may be between 0.1 millimetres and 2 millimetres, between 0.3 millimetres and 1.5 millimetres, between 0.5 millimetres and 1.2 millimetres, or between 0.6 millimetres and 1 millimetre downstream from the upstream end of the tipping paper.

[0148] The upstream end of the classification region may be about 0.8 millimetres downstream from the upstream end of the tipping paper. It has been found that providing the classification region no closer than this distance from the downstream end of the tipping paper may advantageously improve the manufacturability of the aerosol-generating article.

[0149] The tipping paper may be any tipping paper.

[0150] The tipping paper may have any air permeability. The tipping paper may have an air permeability of at less than 10 Coresta units, or less than 5 Coresta units. The tipping paper may have an air permeability of 0 Coresta units.

[0151] The tipping paper may have any brightness. The tipping paper may have a brightness of at least 70 percent d / 8°, at least 75 percent d / 8°, at least 80 percent d / 8°, or at least 85 percent d / 8°.

[0152] The tipping paper may have a brightness of no more than 98 percent d / 8°, no more than 95 percent d / 8°, or no more than 90 percent d / 8°.

[0153] The tipping paper may have a brightness of between 70 percent d / 8° and 98 percent d / 8°, between 75 percent d / 8° and 95 percent d / 8°, or between 85 percent d / 8° and 90 percent d / 8°.

[0154] The tipping paper may have a brightness of about 83.4 percent d / 8°, about 86 percent d / 8°, or about 88.6 percent d / 8°. It has been found that the provision of a classification region provided on a tipping paper having this brightness can advantageously improve the contrast between the tipping paper and the classification identifier. This may improve the reliability of the classification of the aerosolgenerating article.

[0155] The tipping paper may have any grammage. For example, the tipping paper may have a grammage of at least 20 gsm, at least 25 gsm, at least 30 gsm, or at least 35 gsm.

[0156] The tipping paper may have a grammage of no more than 50 gsm, no more than 45 gsm, no more than 40 gsm, or no more than 38 gsm.

[0157] The tipping paper may have a grammage of between 20 gsm and 50 gsm, between 25 gsm and 45 gsm, between 30 gsm and 40 gsm, or between 35 gsm and 38 gsm.

[0158] The tipping paper may have a grammage of about 33.5 gsm, about 36 gsm, about 36.5 gsm, about 38.5 gsm, about 39 gsm, or about 41.1 gsm.

[0159] The tipping paper may have any opacity. The tipping paper may have an opacity of at least 70 percent d / 8°, at least 75 percent d / 8°, or at least 80 percent d / 8°.

[0160] The tipping paper may have an opacity of no more than 98 percent d / 8°, no more than 95 percent d / 8°, or no more than 90 percent d / 8°.

[0161] The tipping paper may have an opacity of between 70 percent d / 8° and 98 percent d / 8°, between 75 percent d / 8° and 95 percent d / 8°, or between 80 percent d / 8° and 90 percent d / 8°.

[0162] The tipping paper may have an opacity of about 79.2 percent d / 8°, about 81.2 percent d / 8°, about 83 percent d / 8°, about 85 percent d / 8°, about 86.8 percent d / 8°, or about 88.8 percent d / 8°.

[0163] The tipping paper may have any thickness. For example, the tipping paper may have a thickness of at least 30 micrometres, at least 35 micrometres, or at least 40 micrometres.

[0164] The tipping paper may have a thickness of no more than 60 micrometres, no more than 55 micrometres, no more than 50 micrometres, or no more than 45 micrometres.

[0165] The tipping paper may have a thickness of between 30 micrometres and 60 micrometres, between 35 micrometres and 55 micrometres, between 40 micrometres and 50 micrometres, or between 40 micrometres and 45 micrometres.

[0166] The tipping paper may have a thickness of about 36 micrometres, about 40 micrometres, about 41 micrometres, about 45 micrometres, about 46 micrometres, or about 50 micrometres.

[0167] The tipping paper may have a smoothness of at least 70 Bekk seconds, at least 80 Bekk seconds, at least 90 Bekk seconds, or at least 100 Bekk seconds.

[0168] The tipping paper may have a smoothness of no more than 250 Bekk seconds, no more than 200 Bekk seconds, no more than 180 Bekk seconds, or no more than 160 Bekk seconds.

[0169] The tipping paper may have a smoothness of between 70 Bekk seconds and 250 Bekk seconds, between 80 Bekk seconds and 200 Bekk seconds, between 90 Bekk seconds and 180 Bekk seconds, or between 100 Bekk seconds and 160 Bekk seconds. The tipping paper may have a smoothness or about 80 Bekk seconds, about 90 Bekk seconds, about 160 Bekk seconds, or about 200 Bekk seconds.

[0170] The tipping paper may have any tensile strain. For example, the tipping paper may have a tensile strain of at least 0.5 percent, or at least 1 percent. The tipping paper may have any tensile strain of less than 2 percent, or less than 1.5 percent.

[0171] The tipping paper may have a tensile strain of between 0.5 percent and 2 percent, or between 1 percent and 1.5 percent. The tipping paper may have any tensile strain of about 1.2 percent or 1 percent. The tensile strain is determined in the machine direction (MD).

[0172] The aerosol-generating substrate may be any aerosol generating substrate. For example, the aerosol-generating article may comprise a rod of aerosol-generating substrate.

[0173] As used herein, the term “aerosol-generating substrate” is used to describe a substrate comprising aerosol-generating material that is capable of releasing upon heating volatile compounds that can form an aerosol.

[0174] The aerosol-generating substrate may be a solid aerosol-generating substrate.

[0175] The aerosol-generating substrate may comprise an aerosol former.

[0176] The aerosol former may be any suitable known compound or mixture of compounds that, in use, facilitates formation of a dense and stable aerosol. The aerosol former may be substantially resistant to thermal degradation at temperatures typically reached during use of the aerosol-generating article.

[0177] Examples of suitable aerosol formers include: polyhydric alcohols such as, for example, triethylene glycol, 1,3-butanediol, propylene glycol and glycerine; esters of polyhydric alcohols such as, for example, glycerol mono-, di- or triacetate; aliphatic esters of mono-, di- or polycarboxylic acids such as, for example, dimethyl dodecanedioate and dimethyl tetradecanedioate; and combinations thereof.

[0178] The aerosol former may comprise one or more of glycerine and propylene glycol. The aerosol former may consist of glycerine. The aerosol former may consist of propylene glycol. The aerosol former may consist of a combination of glycerine and propylene glycol.

[0179] The aerosol-generating substrate may comprise at least 5 percent by weight of aerosol former, at least 10 percent by weight of aerosol former, or at least 15 percent by weight of aerosol former. That is, the aerosol-generating material may have an aerosol former content of at least 5 percent by weight, at least 10 percent by weight, or at least 15 percent by weight.

[0180] The aerosol-generating substrate may comprise less than or equal to 30 percent by weight of aerosol former, less than or equal to 25 percent by weight of aerosol former, or less than or equal to 20 percent by weight of aerosol former. That is, the aerosol-generating material may have an aerosol former content of less than or equal to 30 percent by weight, less than or equal to 25 percent by weight, or less than or equal to 20 percent by weight. For example, the aerosol-generating substrate may comprise between 5 percent and 30 percent by weight of aerosol former, or between 10 percent and 25 percent by weight of aerosol former, or between about 15 percent and about 20 percent by weight of aerosol former. Aerosol former contents within these ranges are subsequently referred to as relatively low aerosol former contents.

[0181] The aerosol-generating substrate may comprise at least 40 percent by weight of aerosol former, at least 50 percent by weight of aerosol former, or at least 60 percent by weight of aerosol former.

[0182] The aerosol-generating substrate may comprise less than or equal to 80 percent by weight of aerosol former, less than or equal to 75 percent by weight of aerosol former, or less than or equal to 70 percent by weight of aerosol former.

[0183] The aerosol-generating substrate may comprise at least 40 percent by weight of aerosol former, at least 45 percent by weight of aerosol former, or at least 50 percent by weight of aerosol former.

[0184] The aerosol-generating substrate may comprise less than or equal to 80 percent by weight of aerosol former, or less than or equal to 75 percent by weight of aerosol former, or less than or equal to 70 percent by weight of aerosol former.

[0185] For example, the aerosol-generating substrate may comprise between 40 percent and 80 percent by weight of aerosol former, or between 45 percent and 75 percent by weight of aerosol former, or between about 50 percent and about 70 percent by weight of aerosol former. Aerosol former contents within these ranges are subsequently referred to as relatively high aerosol former contents.

[0186] The aerosol-generating substrate may comprise nicotine.

[0187] The aerosol-generating substrate may comprise natural nicotine, or synthetic nicotine, or a combination of natural nicotine and synthetic nicotine.

[0188] The aerosol-generating substrate may comprise plant material.

[0189] The aerosol-generating substrate may comprise a plurality of strands of plant material. The aerosol-generating substrate may comprise homogenised plant material.

[0190] The aerosol former content of the homogenised plant material may be within the ranges set out above for relatively low aerosol former contents.

[0191] The aerosol-generating substrate may comprise a plurality of pellets or granules of homogenised plant material.

[0192] The aerosol-generating substrate may comprise one or more sheets of homogenised plant material.

[0193] The aerosol-generating substrate may comprise a plurality of strands of homogenised plant material. Strands of homogenised plant material may be formed by cutting or shredding a sheet of homogenised plant material. Strands of homogenised plant material may be formed by other methods. For example, strands of homogenised plant material may be formed by extrusion.

[0194] The aerosol-generating substrate may comprise non-tobacco plant material. Examples of suitable non-tobacco plant materials include cannabis material, ginger material, eucalyptus material, clove material, and star anise material.

[0195] The aerosol-generating substrate may comprise homogenised non-tobacco plant material.

[0196] The aerosol-generating substrate may comprise a plurality of pellets or granules of homogenised non-tobacco plant material.

[0197] The aerosol-generating substrate may comprise one or more sheets of homogenised non-tobacco plant material.

[0198] The aerosol-generating substrate may comprise a plurality of strands of non-tobacco homogenised plant material.

[0199] The aerosol-generating substrate may comprise tobacco material.

[0200] The aerosol-generating substrate may comprise a plurality of strands of tobacco material. The aerosol-generating substrate may comprise homogenised tobacco material.

[0201] The aerosol-generating substrate may comprise a plurality of pellets or granules of homogenised tobacco material.

[0202] The aerosol-generating substrate may comprise one or more sheets of homogenised tobacco material.

[0203] The aerosol-generating substrate may comprise a plurality of strands of homogenised tobacco material.

[0204] The aerosol-generating article may further comprise an internal heater. The internal heater may comprise an internal susceptor element.

[0205] The internal susceptor element may be arranged within the aerosol-generating substrate. The internal susceptor element may be arranged substantially longitudinally within the aerosolgenerating substrate. That is, a longitudinal axis of the internal susceptor element may be approximately parallel to a longitudinal axis of the aerosol-generating substrate. For example, a longitudinal axis of internal susceptor element may be within plus or minus 10 degrees of parallel to a longitudinal axis of the aerosol-generating substrate.

[0206] The internal susceptor element may be arranged centrally within the aerosol-generating substrate. The internal susceptor element may extend along a longitudinal axis of the aerosolgenerating substrate.

[0207] The internal susceptor element may extend from a downstream end of the aerosolgenerating substrate towards an upstream end of the aerosol-generating substrate.

[0208] The internal susceptor element may extend from an upstream end of the aerosolgenerating substrate towards a downstream end of the aerosol-generating substrate. The internal susceptor element may extend from an upstream end of the aerosolgenerating substrate to a downstream end of the aerosol-generating substrate. That is, the internal susceptor element may extend along the entire length of the aerosol-generating substrate.

[0209] The length of the internal susceptor element may be substantially the same as the length of the aerosol-generating substrate.

[0210] The internal susceptor element may extend part way along the length of the aerosolgenerating substrate.

[0211] The internal susceptor element may be spaced apart from a downstream end of the aerosol-generating substrate.

[0212] The internal susceptor element may be spaced apart from an upstream end of the aerosolgenerating substrate.

[0213] The internal susceptor element may be spaced apart from both a downstream end and an upstream end of the aerosol-generating substrate.

[0214] The length of the internal susceptor element may be less than the length of the aerosolgenerating substrate.

[0215] The internal susceptor element may be in thermal contact with the aerosol-generating substrate. The internal susceptor element may advantageously be in direct contact with the aerosol-generating substrate.

[0216] The internal susceptor element may be entirely enclosed within the aerosol-generating substrate. That is, the aerosol-generating substrate may completely surround the internal heating element.

[0217] According to a second aspect of the present disclosure, there is provided an aerosolgenerating device for use with an aerosol-generating article. The aerosol-generating device may comprise a cavity for receiving at least a portion of the aerosol-generating article according to the first aspect of the present disclosure. The aerosol-generating device may comprise a light sensor arranged to detect at least one colour of a coloured band of an aerosol-generating article. The aerosol-generating device may comprise a power supply configured to supply power to the light sensor.

[0218] According to a second aspect of the present invention, there is provided an aerosolgenerating device for use with an aerosol-generating article. The aerosol-generating device comprises a cavity for receiving at least a portion of the aerosol-generating article according to the first aspect of the present invention. The aerosol-generating device comprises a light sensor arranged to detect at least one colour of a coloured band of an aerosol-generating article. The aerosol-generating device comprises a power supply configured to supply power to the light sensor. The aerosol-generating device may comprise a source of radiation arranged to irradiate a taggant of an aerosol-generating article when the aerosol-generating article is received within the cavity. The aerosol-generating device may comprise a photodetector arranged to detect radiation emitted by a taggant of an aerosol-generating article when the aerosol-generating article is received within the cavity.

[0219] The power supply may be configured to supply power to the source of radiation and the photodetector.

[0220] The photodetector may be located between 15 millimetres and 30 millimetres from the upstream end of the cavity, preferably between 22.3 millimetres and 25.5 millimetres from the upstream end of the cavity.

[0221] The light sensor may be located at least 20 millimetres from the upstream end of the cavity, preferably at least 22.3 millimetres from the upstream end of the cavity.

[0222] The light sensor may be configured to detect the colour of a plurality of coloured bands. The photodetector may be configured to detect the radiation of a taggant when an aerosolgenerating article is stationary within the cavity of the aerosol-generating device. This may be referred to as static reading. The provision of static reading for the taggant may advantageously improve the reliability of the authentication of the aerosol-generating article. Where static reading is used, it may be advantageous for the authorisation region to have a length which is greater than or equal to the field of view, of the photodetector. In this way, the authentication region may be reliably read by the photodetector.

[0223] The photodetector may have any aperture width. For example, the photodetector may have an aperture width of at least 0.5 millimetres, at least 1 millimetre, at least 2 millimetres, at least 3 millimetres, at least 4 millimetres, at least 5 millimetres, or at least 10 millimetres.

[0224] The photodetector may have an aperture width of no more than 20 millimetres, no more than 15 millimetres, no more than 10 millimetres, or no more than 5 millimetres.

[0225] The photodetector may have an aperture width of between 0.5 millimetres and 20 millimetres, between 1 millimetre and 15 millimetres, between 2 millimetres and 10 millimetres, or between 3 millimetre and 5 millimetres.

[0226] The photodetector aperture may have any shape. For example, the photodetector aperture may be circular or rectangular. Preferably, the photodetector aperture is rectangular and has dimensions of 3.5 millimetres by 3.2 millimetres.

[0227] The photodetector may have any field of view. The photodetector may have a field of view of at least 1 millimetre, or at least 1.5 millimetres. The photodetector may have a field of view of no more than 3 millimetres or no more than 2 millimetres. The photodetector may have a field of view of about 2 millimetres or about 1.9 millimetres.

[0228] The photodetector may be arranged such that it is any distance from an outer surface of the aerosol-generating article when the aerosol-generating article is received with the cavity. For example, the photodetector may be arranged such that it is a least 0.4 millimetres, at least 0.5 millimetres, at least 0.7 millimetres, or at least 1 millimetre from an outer surface of the aerosolgenerating article when the aerosol-generating article is received with the cavity. The photodetector may be arranged such that it is no more than 3 millimetres, no more than 2 millimetres, no more than 1.5 millimetres, or no more than 1 millimetre from an outer surface of the aerosol-generating article when the aerosol-generating article is received with the cavity. For example, the photodetector may be arranged such that it is about 0.4 millimetres, about 0.5 millimetres, about 0.7 millimetres, or about 1 millimetre from an outer surface of the aerosolgenerating article when the aerosol-generating article is received with the cavity.

[0229] The photodetector may have any sample rate. For example, the photodetector may have a sample rate of at least 10 KHz, at least 25 KHz, at least 50 KHz, or at least 90 KHz. The photodetector may have a sample rate of no more than 500 KHz, no more than 400 KHz, no more than 300 KHz, or no more than 200 KHz.

[0230] The photodetector may have a sample rate of between 10 KHz and 500 KHz, between 25 KHz, and 400 KHz, between 50 KHz and 300 KHz, or between 90 KHz and 200 KHz.

[0231] Preferably, the photodetector may have a sample rate of between 90KHz and 110KHz, more preferably about 100 KHz.

[0232] As used herein, the term “sample rate” refers to the frequency at which the photodetector or light sensor takes a sample. A sample rate of 50 Hz refers to a sensor which takes 50 samples every second, or 1 sample every 20 milliseconds.

[0233] The light sensor may be configured to detect the colour of the coloured band, or bands, of an aerosol-generating article as the aerosol-generating article is inserted into the cavity of the aerosol-generating device. In this way, the coloured band may pass by the light sensor as the as the aerosol-generating article is inserted into the cavity of the aerosol-generating device. This may be referred to as dynamic reading. The provision of dynamic reading for the coloured band may allow for a plurality of different coloured bands to be identified by the same light sensor. This may advantageously allow for one light sensor to read plurality of different colours allowing for a greater number of different aerosol-generating articles to be differentiated and classified by the aerosol-generating device. Dynamic reading of the coloured band may also advantageously remove the need for the coloured band to be precisely aligned with the light sensor at any point. This may advantageously increase the tolerance of the position of the coloured band on the aerosol-generating article, and the location of the aerosol-generating article in the cavity. In a similar way, dynamic reading of the coloured band may allow the coloured band to have a smaller length.

[0234] Where dynamic reading is used, the classification region may have a length which is less than the field of view of the light sensor since the entire length of the classification region will pass through the field of view of the light sensor. The light sensor may have any aperture width. For example, the light sensor may have an aperture width of at least 0.5 millimetres, at least 1 millimetre, at least 2 millimetres, at least 3 millimetres, at least 4 millimetres, at least 5 millimetres, or at least 10 millimetres.

[0235] The light sensor may have an aperture width of no more than 20 millimetres, no more than 15 millimetres, no more than 10 millimetres, or no more than 5 millimetres.

[0236] The light sensor may have an aperture width of between 0.5 millimetres and 20 millimetres, between 1 millimetre and 15 millimetres, between 1 millimetre and 1 millimetre, or between 1 millimetre and 5 millimetres.

[0237] The light sensor aperture may have any shape. For example, the light sensor aperture may be circular or rectangular. Preferably, the light sensor aperture is circular and has diameter of about 1 millimetre.

[0238] The light sensor may have any field of view. The light sensor may have a field of view of at least 1 millimetre, or at least 1.5 millimetres. The light sensor may have a field of view of no more than 3 millimetres or no more than 2 millimetres. The light sensor may have a field of view of about 2 millimetres or about 1.9 millimetres.

[0239] The light sensor may be arranged such that it is any distance from an outer surface of the aerosol-generating article when the aerosol-generating article is received with the cavity. For example, the light sensor may be arranged such that it is a least 0.4 millimetres, at least 0.5 millimetres, at least 0.7 millimetres, or at least 1 millimetre from an outer surface of the aerosolgenerating article when the aerosol-generating article is received with the cavity. The light sensor may be arranged such that it is no more than 3 millimetres, no more than 2 millimetres, no more than 1.5 millimetres, or no more than 1 millimetre from an outer surface of the aerosol-generating article when the aerosol-generating article is received with the cavity. For example, the light sensor may be arranged such that it is about 0.4 millimetres, about 0.5 millimetres, about 0.7 millimetres, or about 1 millimetre from an outer surface of the aerosol-generating article when the aerosol-generating article is received with the cavity.

[0240] The light sensor may have any sample rate. For example, the light sensor may have a sample rate of at least 50 Hz, at least 100 Hz, at least 500 Hz, or at least 1 KHz. The photodetector may have a sample rate of no more than 10 KHz, no more than 5 KHz, no more than 2.5 KHz, or no more than 1 KHz.

[0241] The light sensor may have a sample rate of between 50 Hz and 10 KHz, between 100 Hz, and 5 KHz, or between 500 Hz and 2.5 KHz.

[0242] Preferably, the photodetector may have a sample rate of between 0.9KHz and 1.1 KHz, more preferably about 1 KHz. The provision of a light sensor having a high sample rate may advantageously facilitate dynamic reading of the coloured band or coloured bands.

[0243] The photodetector may be aligned with the light sensor. The photodetector and the light sensor may be comprised within the same sensor assembly. Where this is the case, dynamic reading of the colour of the coloured band may allow for both the coloured band and the nature of the taggant to be read at different times by the same sensor assembly.

[0244] The aerosol-generating device may further comprise an accelerometer, wherein activation of the accelerometer in configured to initiate a power supply to at least one of the source of radiation, the photodetector, and the light sensor.

[0245] The provision of an accelerometer may advantageously prevent the need for a user to activity initiate the source of radiation, the photodetector, or the light sensor. In addition, the provision of an accelerometer may advantageously remove the need for the source of radiation, the photodetector, or the light sensor to be permanently activated. This may prevent wasting electrical power when the aerosol-generating device in not in use.

[0246] In use, a user is likely to pick up the aerosol-generating device when they wish to use the aerosol-generating device. When this happens, the accelerometer detects this movement and may activate the source of radiation, the photodetector, and the light sensor in anticipation of the user inserting an aerosol-generating article into the cavity. The photodetector and the light sensor may then detect the taggant and the colour of the coloured band as described above.

[0247] The aerosol-generating device may comprise a chamber for receiving at least a portion of the aerosol-generating substrate of the aerosol-generating article, an external heater extending around at least a portion of the chamber, and control circuitry.

[0248] The external heater may at least partially surround or define the chamber for receiving the aerosol-generating article. The external heater may have a coil or helical shape. The external heater may be substantially tubular in shape.

[0249] The external heater may be a resistive heater.

[0250] The external resistive heater may comprise a resistive heating element. The resistive heating element may comprise an electrically insulating substrate, for example a substantially tubular electrically insulating substrate, and an electrically conductive track on the electrically insulating substrate. The control circuitry may be configured to pass an electrical current through the electrically conductive track in use to resistively heat the electrically conductive track.

[0251] As used herein, the term “electrically insulating” may refer to a material having an electrical conductivity of less than 0.8x104 Siemens per metre in at least one direction, for example in all directions, at room temperature (20 degrees Celsius) and a relative humidity of 50%.

[0252] As used herein, the term “electrically conductive” may refer to a material having an electrical conductivity of at least 0.8x106 Siemens per metre in at least one direction, for example in all directions, at room temperature (20 degrees Celsius) and a relative humidity of 50%.

[0253] Suitable electrically insulating materials may include one or more of: glass, ceramic, anodized metal, coated metal, and Polyimide. The ceramic may comprise mica, Alumina or Zirconia. Suitable electrically conductive materials may include one or more of: semiconductors such as doped ceramics, electrically “conductive” ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys and composite materials made of a ceramic material and a metallic material. Such composite materials may comprise doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbides. Examples of suitable metals include titanium, zirconium, tantalum and metals from the platinum group. Examples of suitable metal alloys include stainless steel, nickel-, cobalt-, chromium-, aluminiumtitanium- zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese- and iron-containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel, Timetai® and iron-manganese-aluminium based alloys. The electrically resistive track may comprise a heating wire or filament, for example a Ni-Cr (Nickel-Chromium), platinum, tungsten or alloy wire or filament.

[0254] Where the external heater is an electrically resistive heater, the external heater may comprise or be formed from one or both of a substantially magnetically transparent material and a non-inductively heatable material. This may be particularly advantageous where the system also comprises an inductor coil, as further described herein.

[0255] The external heater may comprise an external susceptor element extending around at least a portion of the chamber and an inductor coil. The control circuitry may be configured to provide an alternating electric current to the inductor coil such that, in use, the inductor coil generates an alternating magnetic field to inductively heat the external susceptor element.

[0256] As used herein, the term “susceptor” refers to an element comprising a material that is capable of converting the energy of a magnetic field into heat. When a susceptor is located in an alternating magnetic field, the susceptor is heated. Heating of the susceptor may be the result of at least one of hysteresis losses and eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material.

[0257] The aerosol-generating device may comprise the internal heater.

[0258] The internal heater may be arranged to be at least partially received within the aerosolgenerating section when the aerosol-generating article is received within the chamber.

[0259] The internal heater may extend from a base or a closed end of the chamber. The internal heater may extend into the chamber, for example towards an open end of the chamber. The internal heater may be shaped as a pin, blade, or rod for penetrating the aerosol-generating section of the aerosol-generating article when the article is inserted into the chamber.

[0260] The internal heater may be a resistive heater.

[0261] The internal resistive heater may comprise a resistive heating element. The resistive heating element may comprise an electrically insulating substrate, for example a substantially tubular electrically insulating substrate, and an electrically conductive track on the electrically insulating substrate. The control circuitry may be configured to pass an electrical current through the electrically conductive track in use to resistively heat the electrically conductive track.

[0262] Suitable electrically insulating materials may include one or more of: glass, ceramic, anodized metal, coated metal, and Polyimide. The ceramic may comprise mica, Alumina or Zirconia.

[0263] Suitable electrically conductive materials may include one or more of: semiconductors such as doped ceramics, electrically “conductive” ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys and composite materials made of a ceramic material and a metallic material. Such composite materials may comprise doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbides. Examples of suitable metals include titanium, zirconium, tantalum and metals from the platinum group. Examples of suitable metal alloys include stainless steel, nickel-, cobalt-, chromium-, aluminiumtitanium- zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese- and iron-containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel, Timetai® and iron-manganese-aluminium based alloys. The electrically resistive track may comprise a heating wire or filament, for example a Ni-Cr (Nickel-Chromium), platinum, tungsten or alloy wire or filament.

[0264] The internal heater may comprise an internal susceptor element arranged to be at least partially received within the aerosol-generating section of the aerosol-generating article when the aerosol-generating article is received within the chamber.

[0265] As previously described, the internal susceptor element may form part of the aerosolgenerating article. The internal susceptor element may be arranged within the aerosol-generating section of the aerosol-generating article. The internal susceptor element may be arranged in direct contact with the aerosol-generating substrate of the aerosol-generating section. The internal susceptor element may be embedded within the aerosol-generating substrate of the aerosol-generating section.

[0266] The internal susceptor element may form part of the aerosol-generating device. The internal susceptor element may be arranged for insertion into the aerosol-generating section of the aerosol-generating article when the article is inserted into the chamber.

[0267] The aerosol-generating device may comprise an inductor coil, wherein the control circuitry is configured to provide an alternating electric current to the inductor coil such that, in use, the inductor coil generates an alternating magnetic field to inductively heat the internal susceptor element. In embodiments in which the external heater comprises an external susceptor element, preferably, the inductor coil may be a single inductor coiled arranged to inductively heat both the external susceptor element and the internal susceptor element. Alternatively, the aerosolgenerating device may comprise a first inductor coil arranged to inductively heat the external susceptor element and a second inductor coil arranged to inductively heat the internal susceptor element.

[0268] The internal susceptor element may comprise or consist of one or more susceptor materials. Suitable susceptor materials may include but are not limited to: carbon, carbon-based materials, graphene, graphite, expanded graphite, molybdenum, silicon carbide, stainless steels, niobium, aluminium, nickel, nickel-containing compounds, titanium, and composites of metallic materials. Suitable susceptor materials may comprise a ferromagnetic material, for example, ferritic iron, a ferromagnetic alloy, such as ferromagnetic steel or stainless steel, ferromagnetic particles, and ferrite. A susceptor material may comprise more than 5 percent, preferably more than 20 percent, more preferably more than 50 percent or more than 90 percent of ferromagnetic or paramagnetic materials. Preferred susceptor materials may comprise a metal, metal alloy or carbon.

[0269] In embodiments in which the aerosol-generating device comprises an inductor coil, the inductor coil may form the external resistive heater. The control circuitry may be configured to provide an alternating electric current to the inductor coil to generating an alternating magnetic field to inductively heat one or more susceptor elements, and the control circuitry may be configured to provide a direct electric current to the inductor coil to resistively heat the inductor coil. For example, the control circuitry may be configured to switch between providing the alternating current and the direct current to the inductor coil. The internal heater may comprise an internal susceptor element, wherein during use the inductor coil inductively heats the internal susceptor element and the inductor coil is resistively heated as the external heater. When the control circuitry is configured to simultaneously heat the external heater and the internal heater, the control circuitry may be configured to rapidly switch back and forth between providing the alternating current to the inductor coil and providing the direct current to the inductor coil.

[0270] The aerosol-generating device may comprise both an external heater and an internal heater.

[0271] The control circuitry may be configured to heat the internal heater and the external heater so that the internal heater reaches the maximum internal heater temperature a predetermined time period after the external heater reaches the maximum external heater temperature.

[0272] As used herein, the maximum temperature of a heater refers to the peak temperature reached at any location on the surface of the heater, at any time during a heating cycle. In other words, the maximum temperature of a heater is the maximum temperature reached at a location on the surface of the heater at any point during a heating cycle, relative to the temperatures reached at other locations on the surface of the heater during a heating cycle. As used herein, the maximum temperature of a heater does not refer to a peak average temperature reached across the surface of the heater during a heating cycle. The maximum temperature of a heater may be determined in any suitable way and by any suitable means. For example, the maximum temperature of a heater may be determined by initially determining a hot-spot location on the surface of the heater, and subsequently determining the maximum temperature reached at the hot-spot location during a heating cycle. As used herein, the hot-spot location refers to the location on the surface of the heater that reaches the highest temperatures during a heating cycle. The determination of the hot-spot location on the surface of the heater may be performed using a non-contact infrared sensor to map relative temperatures reached at locations across the surface of the heater during a heating cycle, and to identify the location at which the highest temperatures are reached. The subsequent determination of the maximum temperature reached at the hot-spot location may be performed using a thermocouple positioned on the surface of the heater at the hot-spot location to measure the temperatures reached at the hot-spot location during a heating cycle, and to identify the peak temperature reached at the hot-spot location.

[0273] The control circuitry may be configured to heat the internal heater to an internal heater temperature during a heating cycle, wherein the control circuitry is configured to heat the external heater to an external heater temperature during the heating cycle, and wherein the control circuitry is configured to change a difference between the internal heater temperature and the external heater temperature during the heating cycle. Advantageously, changing a difference between the internal heater temperature and the external heater temperature during a heating cycle may facilitate reducing a time between the start of the heating cycle and generation of aerosol from the aerosol-generating substrate, and providing a relatively consistent delivery of aerosol during the heating cycle. For example, the difference between the internal heater temperature and the external heater temperature may be relatively large at the start of the heating cycle as a result of a high initial internal heater temperature to provide a rapid start of aerosol generation. Once aerosol generation has started, the internal heater temperature may be reduced and the external heater temperature may be increased to provide more even heating of the aerosol-generating substrate during the remainder of the heating cycle.

[0274] The heating cycle that the control circuitry may use to heat the internal heater and the external heater may be determined based on the stick classification made by the light sensor and control circuitry. In this way, the control circuitry may be able to control the balance of heat delivery to the aerosol-generating substrate by the internal heater and the external heater based on the specific type of aerosol-generating substrate as determined by the classification region.

[0275] According to a third aspect of the present disclosure, there is provided an aerosolgenerating system comprising an aerosol-generating article, an aerosol-generating device, and an internal heater. The aerosol-generating article may be according to the first aspect of the present disclosure. The aerosol-generating device may comprise a chamber for receiving at least a portion of the aerosol-generating substrate of the aerosol-generating article. The aerosol- generating device may comprise an external heater extending around at least a portion of the chamber. The aerosol-generating device may comprise control circuitry. The internal heater may be arranged inside at least part of the aerosol-generating substrate when the aerosol-generating article is received within the chamber.

[0276] The invention is defined in the claims. However, below there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0277] Example Ex1. An aerosol-generating article for use with an aerosol-generating device to generate an aerosol, the aerosol-generating article comprising: an aerosol-generating substrate, at least one wrapper defining the longitudinal surface of the aerosol-generating article extending between an upstream end of the aerosol-generating article and a downstream end of the aerosolgenerating article, the longitudinal surface defining a generally cylindrical shape, a classification region provided on the at least one wrapper, the classification region comprising an identifier readable by a sensor of an aerosol-generating device, wherein the at least one wrapper comprises a tipping paper and a cigarette paper, the tipping paper extending to the downstream end of the aerosol-generating article, and the cigarette paper extending to the upstream end of the aerosol-generating article, the cigarette paper circumscribing the aerosol-generating substrate, and wherein the classification region is provided on the tipping paper.

[0278] Example Ex 2. An aerosol-generating article according to Example Ex 1, wherein the classification region is provided as a band at least partially circumscribing the longitudinal surface of the aerosol-generating article, the classification region extending longitudinally between an upstream end and a downstream end.

[0279] Example Ex 4. An aerosol-generating article according to any preceding Example, wherein the classification region does not overlay the aerosol-generating substrate.

[0280] Example Ex 27. An aerosol-generating article according to any preceding Example, wherein the classification region has a length between the upstream end of the classification region and the downstream end of the classification region of at least 0.5 millimetres, preferably at least 1 millimetre, more preferably at least 1.5 millimetres, still more preferably at least 2 millimetres.

[0281] Example Ex 28. An aerosol-generating article according to any preceding Example, wherein the classification region has a length between the upstream end of the classification region and the downstream end of the classification region of no more than 5 millimetres, preferably no more than 4.5 millimetres, more preferably no more than 4 millimetres, still more preferably no more than 3 millimetres.

[0282] Example Ex 29. An aerosol-generating article according to any preceding Example, wherein the classification region has a length between the upstream end of the classification region and the downstream end of the classification region of between 0.5 millimetres and 5 millimetres, preferably between 1 millimetre and 4.5 millimetres, more preferably between 1.5 millimetres and 4 millimetres, still more preferably between 2 millimetres and 3 millimetres.

[0283] Example Ex 30. An aerosol-generating article according to any preceding Example, wherein the classification region has a length between the upstream end of the classification region and the downstream end of the classification region of about 2.8 millimetres.

[0284] Example Ex 31. An aerosol-generating article according to any preceding Example, wherein the upstream end of the classification region is at least 15 millimetres from the upstream end of the aerosol-generating article, preferably at least 17 millimetres from the upstream end of the aerosol-generating article, more preferably at least 19 millimetres from the upstream end of the aerosol-generating article.

[0285] Example Ex 32. An aerosol-generating article according to any preceding Example, wherein the upstream end of the classification region is no more than 24 millimetres from the upstream end of the aerosol-generating article, preferably no more than 22 millimetres from the upstream end of the aerosol-generating article, more preferably no more than 20 millimetres from the upstream end of the aerosol-generating article.

[0286] Example Ex 33. An aerosol-generating article according to any preceding Example, wherein the upstream end of the classification region is between 15 millimetres and 24 millimetres from the upstream end of the aerosol-generating article, preferably between 17 millimetres and 22 millimetres from the upstream end of the aerosol-generating article, more preferably between 19 millimetres and 20 millimetres from the upstream end of the aerosol-generating article.

[0287] Example Ex 34. An aerosol-generating article according to any preceding Example, wherein the upstream end of the classification region is about 19.5 millimetres from the upstream end of the aerosol-generating article.

[0288] Example Ex 35. An aerosol-generating article according to any preceding Example, wherein the upstream end of the classification region is at least 20 millimetres from the downstream end of the aerosol-generating article, preferably at least 22 millimetres from the downstream end of the aerosol-generating article, more preferably at least 25 millimetres from the downstream end of the aerosol-generating article.

[0289] Example Ex 36. An aerosol-generating article according to any preceding Example, wherein the upstream end of the classification region is no more than 30 millimetres from the downstream end of the aerosol-generating article, preferably no more than 28 millimetres from the downstream end of the aerosol-generating article, more preferably no more than 26 millimetres from the downstream end of the aerosol-generating article.

[0290] Example Ex 37. An aerosol-generating article according to any preceding Example, wherein the upstream end of the classification region is between 20 millimetres and 30 millimetres from the downstream end of the aerosol-generating article, preferably between 22 millimetres and 28 millimetres from the downstream end of the aerosol-generating article, more preferably between 25 millimetres and 26 millimetres from the downstream end of the aerosol-generating article.

[0291] Example Ex 38. An aerosol-generating article according to any preceding Example, wherein the upstream end of the classification region is about 25.5 millimetres from the downstream end of the aerosol-generating article.

[0292] Example Ex 39. An aerosol-generating article according to any preceding Example, wherein the downstream end of the classification region is at least 15 millimetres from the downstream end of the aerosol-generating article, preferably at least 20 millimetres from the downstream end of the aerosol-generating article, more preferably at least 22 millimetres from the downstream end of the aerosol-generating article.

[0293] Example Ex 40. An aerosol-generating article according to any preceding Example, wherein the downstream end of the classification region is no more than 30 millimetres from the downstream end of the aerosol-generating article, preferably no more than 25 millimetres from the downstream end of the aerosol-generating article, more preferably no more than 23 millimetres from the downstream end of the aerosol-generating article.

[0294] Example Ex 41. An aerosol-generating article according to any preceding Example, wherein the downstream end of the classification region is between 15 millimetres and 30 millimetres from the downstream end of the aerosol-generating article, preferably between 20 millimetres and 25 millimetres from the downstream end of the aerosol-generating article, more preferably between 22 millimetres and 23 millimetres from the downstream end of the aerosolgenerating article.

[0295] Example Ex 42. An aerosol-generating article according to any preceding Example, wherein the downstream end of the classification region is about 22.7 millimetres from the downstream end of the aerosol-generating article.

[0296] Example Ex 43. An aerosol-generating article according to any preceding Example, wherein the downstream end of the classification region is at least 18 millimetres from the upstream end of the aerosol-generating article, preferably at least 20 millimetres from the upstream end of the aerosol-generating article, more preferably at least 22 millimetres from the upstream end of the aerosol-generating article.

[0297] Example Ex 44. An aerosol-generating article according to any preceding Example, wherein the downstream end of the classification region is no more than 28 millimetres from the upstream end of the aerosol-generating article, preferably no more than 25 millimetres from the upstream end of the aerosol-generating article, more preferably no more than 23 millimetres from the upstream end of the aerosol-generating article.

[0298] Example Ex 45. An aerosol-generating article according to any preceding Example, wherein the downstream end of the classification region is between 18 millimetres and 28 millimetres from the upstream end of the aerosol-generating article, preferably between 20 millimetres and 25 millimetres from the upstream end of the aerosol-generating article, more preferably between 22 millimetres and 23 millimetres from the upstream end of the aerosolgenerating article.

[0299] Example Ex 46. An aerosol-generating article according to any preceding Example, wherein the downstream end of the classification region is about 22.3 millimetres from the upstream end of the aerosol-generating article.

[0300] Example Ex 47. An aerosol-generating article according to any preceding Example, wherein the aerosol-generating article has a total length between the upstream end of the aerosolgenerating article and the downstream end of the aerosol-generating article of at least 30 millimetres, preferably at least 35 millimetres, more preferably at least 40 millimetres.

[0301] Example Ex 48. An aerosol-generating article according to any preceding Example, wherein the aerosol-generating article has a total length between the upstream end of the aerosolgenerating article and the downstream end of the aerosol-generating article of no more than 60 millimetres, preferably no more than 55 millimetres, more preferably no more than 50 millimetres.

[0302] Example Ex 49. An aerosol-generating article according to any preceding Example, wherein the aerosol-generating article has a total length between the upstream end of the aerosolgenerating article and the downstream end of the aerosol-generating article of between 30 millimetres and 60 millimetres, preferably between 35 millimetres and 55 millimetres, more preferably between 40 millimetres and 50 millimetres.

[0303] Example Ex 50. An aerosol-generating article according to any preceding Example, wherein the aerosol-generating article has a total length between the upstream end of the aerosolgenerating article and the downstream end of the aerosol-generating article of about 45 millimetres.

[0304] Example Ex 68. An aerosol-generating article according to any preceding Example, wherein the identifier is provided on the outer surface of the at least one wrapper.

[0305] Example Ex 69. An aerosol-generating article according to any preceding Example, wherein the identifier comprises at least one coloured band fully circumscribing the longitudinal surface of the aerosol-generating article, the at least one coloured band having a consistent colour extending around the full circumference of the longitudinal surface.

[0306] Example Ex 70. An aerosol-generating article according to Example Ex 69, wherein the at least one coloured band has a length between an upstream end of the at least one coloured band and the downstream end of the at least one coloured band of at least 0.1 millimetres, preferably at least 0.25 millimetres, more preferably at least 0.5 millimetres.

[0307] Example Ex 71. An aerosol-generating article according to Example Ex 69 or Example Ex 70, wherein the at least one coloured band has a length between an upstream end of the at least one coloured band and the downstream end of the at least one coloured band of no more than 5 millimetres, preferably no mor than 3 millimetres, more preferably no more than 1 millimetre.

[0308] Example Ex 72. An aerosol-generating article according to any one of Example Ex 69 to Ex 71, wherein the at least one coloured band has a length between an upstream end of the at least one coloured band and the downstream end of the at least one coloured band of between 0.1 millimetres and 5 millimetres, preferably between 0.25 millimetres and 3 millimetres, more preferably between 0.5 millimetres and 1 millimetre.

[0309] Example Ex 73. An aerosol-generating article according to any one of Example Ex 69 to Ex 72, wherein the at least one coloured band has a length between an upstream end of the at least one coloured band of about 0.5 millimetres.

[0310] Example Ex 74. An aerosol-generating article according to any one of Example Ex 69 to Ex 73, wherein the at least one coloured band has a length between an upstream end of the at least one coloured band of about 1 millimetre.

[0311] Example Ex 75. An aerosol-generating article according to any one of Example Ex 69 to Ex 74, wherein the identifier comprises a plurality of coloured bands.

[0312] Example Ex 76. An aerosol-generating article according to any one of Example Ex 69 to Ex 75, wherein the identifier comprises a first coloured band having a first colour and a second coloured band having a second colour.

[0313] Example Ex 77. An aerosol-generating article according to Example Ex 76, wherein the first colour is different to the second colour.

[0314] Example Ex 78. An aerosol-generating article according to Example Ex 76 or Example Ex 77, wherein the first coloured band is longer than the second coloured band.

[0315] Example Ex 79. An aerosol-generating article according to any one of Example Ex 76 to Ex 78, wherein the first coloured band is entirely downstream of the second coloured band.

[0316] Example Ex 80. An aerosol-generating article according to any one of Example Ex 76 to Ex 79, wherein the first coloured band and the second coloured band are separated by at least 0.1 millimetres, preferably at least 0.25 millimetres, more preferably at least 0.5 millimetres.

[0317] Example Ex 81. An aerosol-generating article according to any one of Example Ex 76 to Ex 80, wherein the first coloured band and the second coloured band are separated by no more than 2 millimetres, preferably no more than 1.5 millimetres, more preferably no more than 1 millimetres.

[0318] Example Ex 82. An aerosol-generating article according to any one of Example Ex 76 to Ex 81 , wherein the first coloured band and the second coloured band are separated by between 0.1 millimetres and 2 millimetres, preferably between 0.25 millimetres and 1.5 millimetres, more preferably between 0.5 and 1 millimetre. Example Ex 83. An aerosol-generating article according to any one of Example Ex 76 to Ex 82, wherein the first coloured band and the second coloured band are separated by about 1 millimetre.

[0319] Example Ex 84. An aerosol-generating article according to any one of Example Ex 76 to Ex 83, wherein the first coloured band has a length of about 1 millimetre.

[0320] Example Ex 85. An aerosol-generating article according to any one of Example Ex 76 to Ex 84, wherein the second coloured band has a length of about 0.5 millimetres.

[0321] Example Ex 86. An aerosol-generating article according to any one of Example Ex 76 to Ex 85, wherein the first coloured band is entirely downstream of the second coloured band.

[0322] Example Ex 90. An aerosol-generating article according to any one of Example Ex 87 to Ex 89, wherein the upstream end of the tipping paper is at least 15 millimetres from the downstream end of the aerosol-generating article, preferably at least 20 millimetres from the downstream end of the aerosol-generating article, more preferably at least 25 millimetres from the downstream end of the aerosol-generating article.

[0323] Example Ex 91. An aerosol-generating article according to any one of Example Ex 87 to Ex 90, wherein the upstream end of the tipping paper is no more than 35 millimetres from the downstream end of the aerosol-generating article, preferably no more than 30 millimetres from the downstream end of the aerosol-generating article, more preferably no more than 28 millimetres from the downstream end of the aerosol-generating article.

[0324] Example Ex 92. An aerosol-generating article according to any one of Example Ex 87 to Ex 91, wherein the upstream end of the tipping paper is about 26 millimetres from the downstream end of the aerosol-generating article.

[0325] Example Ex 93. An aerosol-generating device for use with an aerosol-generating article, the aerosol-generating device comprising: a cavity for receiving at least a portion of the aerosol-generating article, a light sensor arranged to detect at least one colour of a coloured band of an aerosol-generating article; and a power supply configured to supply power to the light sensor.

[0326] Example Ex 93a. An aerosol-generating device according to Example Ex 93, further comprising a source of radiation arranged to irradiate a taggant of an aerosol-generating article when the aerosol-generating article is received within the cavity; a photodetector arranged to detect radiation emitted by a taggant of an aerosol-generating article when the aerosol-generating article is received within the cavity.

[0327] Example Ex 94. An aerosol-generating device according to Example Ex 93a, wherein the cavity is for receiving at least a portion of an aerosol-generating article according to any one of Example Ex 1 to Ex 92.

[0328] Example Ex 95. An aerosol-generating device according to Example Ex 93a or Example Ex 94, wherein the photodetector has an aperture width of at least 0.5 millimetres, preferably at least 1 millimetre, more preferably at least 2 millimetres, more preferably at least 3 millimetres.

[0329] Example Ex 96. An aerosol-generating device according to any one of Example Ex 93a to Ex 95, wherein the photodetector has an aperture width of no more than 20 millimetres, preferably no more than 15 millimetres, more preferably no more than 10 millimetres, more preferably no more than 5 millimetres.

[0330] Example Ex 97. An aerosol-generating device according to any one of Example Ex 93a to Ex 96, wherein the photodetector has a have a field of view of at least 1 millimetre.

[0331] Example Ex 98. An aerosol-generating device according to any one of Example Ex 93a to Ex 97, wherein the photodetector has a have a field of view of no more than 3 millimetres.

[0332] Example Ex 99. An aerosol-generating device according to any one of Example Ex 93a to Ex 98, wherein the photodetector is arranged such that it is a least 0.4 millimetres, preferably at least 0.5 millimetres, more preferably at least 0.7 millimetres, more preferably at least 1 millimetre from an outer surface of the aerosol-generating article when the aerosolgenerating article is received with the cavity.

[0333] Example Ex 100. An aerosol-generating device according to any one of Example Ex 93a to Ex 99, wherein the photodetector is arranged such that it is no more than 3 millimetres, preferably no more than 2 millimetres, more preferably no more than 1.5 millimetres, more preferably no more than 1 millimetre from an outer surface of the aerosol-generating article when the aerosol-generating article is received with the cavity.

[0334] Example Ex 101. An aerosol-generating device according to any one of Example Ex 93a to Ex 100, wherein the photodetector has a sample rate of at least 10 KHz, preferably at least 25 KHz, more preferably at least 50 KHz, more preferably at least 90 KHz.

[0335] Example Ex 102. An aerosol-generating device according to any one of Example Ex 93a to Ex 101 , wherein the photodetector has a sample rate of no more than 500 KHz, preferably no more than 400 KHz, more preferably no more than 300 KHz, more preferably no more than 200 KHz.

[0336] Example Ex 103. An aerosol-generating device according to any one of Example Ex 93a to Ex 102, wherein the light sensor has an aperture width of at least 0.5 millimetres, preferably at least 1 millimetre.

[0337] Example Ex 104. An aerosol-generating device according to any one of Example Ex 93a to Ex 103, wherein the light sensor has an aperture width of no more than 20 millimetres, preferably no more than 15 millimetres, more preferably no more than 10 millimetres, more preferably no more than 5 millimetres.

[0338] Example Ex 105. An aerosol-generating device according to any one of Example Ex 93a to Ex 104, wherein the light sensor has a have a field of view of at least 1 millimetre. Example Ex 106. An aerosol-generating device according to any one of Example Ex 93a to Ex 105, wherein the light sensor has a have a field of view of no more than 3 millimetres.

[0339] Example Ex 107. An aerosol-generating device according to any one of Example Ex 93a to Ex 106, wherein the light sensor is arranged such that it is a least 0.4 millimetres, preferably at least 0.5 millimetres, more preferably at least 0.7 millimetres, more preferably at least 1 millimetre from an outer surface of the aerosol-generating article when the aerosol-generating article is received with the cavity.

[0340] Example Ex 108. An aerosol-generating device according to any one of Example Ex 93a to Ex 107, wherein the light sensor is arranged such that it is no more than 3 millimetres, preferably no more than 2 millimetres, more preferably no more than 1.5 millimetres, more preferably no more than 1 millimetre from an outer surface of the aerosol-generating article when the aerosol-generating article is received with the cavity.

[0341] Example Ex 109. An aerosol-generating device according to any one of Example Ex 93a to Ex 108, wherein the light sensor has a sample rate of at least 50 Hz, preferably at least 100 Hz, more preferably at least 100 Hz, more preferably at least 500 Hz, more preferably at least 1 KHz

[0342] Example Ex 110. An aerosol-generating device according to any one of Example Ex 93a to Ex 109, wherein the light sensor has a sample rate of no more than 10 KHz, preferably no more than 5 KHz, more preferably no more than 2.5 KHz, more preferably no more than 1 KHz.

[0343] Example Ex 111. An aerosol-generating device according to any one of Example Ex 93a to Ex 110, wherein the photodetector is located between 15 millimetres and 30 millimetres from the upstream end of the cavity, preferably between 22.3 millimetres and 25.5 millimetres from the upstream end of the cavity.

[0344] Example Ex 112. An aerosol-generating device according to any one of Example Ex 93 to Ex 111 , wherein the light sensor is located at least 20 millimetres from the upstream end of the cavity, preferably at least 22.3 millimetres from the upstream end of the cavity.

[0345] Example Ex 113. An aerosol-generating device according to any one of Example Ex 93a to Ex 112, further comprising an accelerometer, wherein activation of the accelerometer in configured to initiate a power supply to at least one of the source of radiation, the photodetector, and the light sensor.

[0346] Example Ex 114. An aerosol-generating system for generating an aerosol, the aerosol-generating system comprising, an aerosol-generating device according to any one of Example Ex 93a to Ex 113, and an aerosol-generating article according to any one of Example Ex 1 to Ex 92 received within the cavity.

[0347] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a plan view of a first aerosol-generating article according to the present invention;

[0348] Figure 2 shows a plan view of a third aerosol-generating article according to the present invention;

[0349] Figure 3 shows a cross-sectional view of an aerosol-generating device according to the present invention;

[0350] Figure 4 shows a cross-sectional view of an aerosol-generating system according to the present invention;

[0351] Figure 5 shows a side cross-sectional view of an aerosol-generating device according to the present disclosure; and

[0352] Figure 6 shows a side cross-sectional view of an aerosol-generating system comprising the aerosol-generating device of Figure 5.

[0353] An aerosol-generating article 100 is shown in Figure 1. The aerosol-generating article extends from an upstream end 101 to a downstream end 102. The aerosol-generating article 100 comprises an aerosol-generating substrate (not shown). The aerosol-generating substrate is located towards the upstream end of the aerosol-generating article 100. The aerosol-generating article comprises at least one wrapper 103. The at least one wrapper 103 extends from the upstream end 101 to the downstream end 102 of the aerosol-generating article 100. The at least one wrapper 103 defines a longitudinal surface of the aerosol-generating article 100. The longitudinal surface defines a generally cylindrical shape such that the aerosol-generating article 100 takes the form of a cylinder.

[0354] The aerosol-generating article 100 further comprises a classification region 105 provided on the at least one wrapper 103, the classification region 105 comprising a classification identifier readable by a sensor of an aerosol-generating device.

[0355] The classification region 105 is provided as a band fully circumscribing the longitudinal surface of the aerosol-generating article 100. The classification region 105 extends longitudinally between an upstream end and a downstream end.

[0356] The authentication region 104 does not overlie the aerosol-generating substrate.

[0357] The classification region 105 has a length between the upstream end of the classification region and the downstream end of the classification region of about 2.8 millimetres.

[0358] The upstream end of the classification region 105 is about 19.5 millimetres from the upstream end 101 of the aerosol-generating article 100.

[0359] The upstream end of the classification region 105 is about 25.5 millimetres from the downstream end 102 of the aerosol-generating article 100.

[0360] The downstream end of the classification region 105 is about 22.7 millimetres from the downstream end 102 of the aerosol-generating article 100. The downstream end of the classification region 105 is about 22.3 millimetres from the upstream end 101 of the aerosol-generating article 100.

[0361] The aerosol-generating article 100 has a total length between the upstream end 101 of the aerosol-generating article 100 and the downstream end 102 of the aerosol-generating article 100 of about 45 millimetres.

[0362] The classification identifier is provided on the outer surface of the at least one wrapper 103. The classification identifier comprises a first 107 and a second 108 coloured band fully circumscribing the longitudinal surface of the aerosol-generating article 100. The first 107 and a second 108 coloured bands are printed on the outer surface of the at least one wrapper 103. The first coloured band 107 has a length of about 1 millimetre. The second coloured band has a length of about 0.5 millimetres. The first coloured band 107 has a first colour. The second coloured band 108 has a second colour. The first colour is different to the first colour. The first coloured band 107 and the second coloured band 108 are separated by about 1 millimetre.

[0363] In the example embodiment shown in Figure 1, the authentication region 104 is entirely downstream of the classification region 105.

[0364] A further example embodiment is shown in Figure 2. The aerosol-generating article 300 includes most of the same features of the aerosol-generating article 100 shown in Figure 1, and similar reference numerals are used to refer to the common features. The aerosol-generating article 300 in Figure 2 differs from the aerosol-generating article 100 of Figure 1 in that the at least one wrapper comprises a cigarette paper 310 which extends to the upstream end 301 of the aerosol-generating article 300, and a tipping paper 311 which extends to the downstream end of the aerosol-generating article 300. The upstream end of the tipping paper 311 is about 26 millimetres from the downstream end 302 of the aerosol-generating article 300.

[0365] The classification region 305 is provided on the tipping paper.

[0366] Figure 3 shows a cross-sectional view of an aerosol-generating device 400 according to the present invention, the aerosol-generating device 400 comprises a cavity 401 for receiving at least a portion of an aerosol-generating article. The cavity 401 extends from an upstream end 402 to a downstream end 403. The aerosol-generating device 400 comprises a light sensor 406 arranged to detect at least one colour of a coloured band of an aerosol-generating article. The aerosol-generating device 400 comprises a heating element 407 arranged to heat the aerosolgenerating substrate of an aerosol-generating article received within the cavity 401. The aerosolgenerating device comprises a power supply 408 configured to supply power to the light sensor 406, and the heating element 407. The light sensor 406 is located at least 20 millimetres from the upstream end 402 of the cavity 401.

[0367] The aerosol-generating device 400 further comprises an accelerometer 409 configured such that activation of the accelerometer 409 activates the light sensor 406. Figure 4 shows an aerosol-generating system 500 comprising the aerosol-generating device 400 shown in Figure 3 with the aerosol-generating article 100 of Figure 1 received in the cavity 401.

[0368] In use, when a user picks up the aerosol-generating device 400, the accelerometer 409 detects the movement. The activation of the accelerometer 409 initiates the supply of power from the power supply 408 to the light sensor 406.

[0369] A user then inserts the aerosol-generating article 100 into the downstream end 403 of the cavity 401 of the aerosol-generating device 400. As the classification region 105 passes the light sensor 406, the light sensor 406 is able to detect the colours of the first 107 and second 108 coloured bands. The aerosol-generating device 400 is able to determine the type, or classification, of the aerosol-generating article 100 based on the combination of colours of the first 107 and second 108 coloured bands.

[0370] Once it has been determined what type, or classification, of aerosol-generating article 100 it is, the heating element 407 may be activated in accordance with a specific heating profile to heat the aerosol-generating substrate within the aerosol-generating article to generate an aerosol.

[0371] Figure 5 shows an aerosol-generating device 510 in accordance with the present disclosure. The aerosol-generating device 510 comprises a housing 512 partially defining a chamber 516 for receiving a portion of an aerosol-generating article. The chamber 516 comprises a first end 518 through which an aerosol-generating article may be inserted into the chamber 516 and a second end 520 opposite the first end 518.

[0372] The aerosol-generating device 510 also comprises a heat-conducting element 528 comprising an outer surface 521 and an inner surface 523. The inner surface 523 has a cylindrical shape and is free from grooves, channels, and other discontinuities. Therefore, the inner surface 523 is smooth and forms a curved plane at least partially defining a cylindrical wall 522 of the chamber 516 that extends between the first end 518 and the second end 520. The heat-conducting element 528 is arranged so that an aerosol-generating article is received within the heat-conducting element 528 and in direct contact with the cylindrical inner surface 523 of the heat-conducting element 528 when the aerosol-generating article is inserted into the chamber 516.

[0373] An inductor coil 524 comprising a plurality of windings 526 extends around an outer surface of the heat-conducting element 528. The inductor coil 524 and the heat-conducting element 528 are arranged concentrically about a central axis 536 of the aerosol-generating device 510.

[0374] As shown in Figure 5, the housing 512 defines a plurality of air inlets 525 extending through an outer surface of the housing 512 and an airflow passage 527 extending from each air inlet 525. The plurality of airflow passages 527 combine into a single common airflow passage 530 in fluid communication with the second end 520 of the chamber 516. In the embodiment shown in Figure 5, the housing 512 defines two air inlets 525 and two airflow passages 527 positioned on opposite sides of the housing 512. The skilled person will appreciate that the housing 512 may define more or fewer air inlets 525 and airflow passages 527 and the arrangement of the air inlets 525 and the airflow passages 527 around the housing 512 may be varied.

[0375] The aerosol-generating device 510 also comprises control circuitry 540 and a power supply 542 connected to the inductor coil 524. The control circuitry 540 is configured to provide an alternating electric current from the power supply 542 to the inductor coil 524 to generate an alternating magnetic field. The control circuitry 540 is also configured to provide a direct electric current from the power supply 542 to the heat-conducting element 528. In this way, the heat-conducting element 528 functions as a resistively heated external heater 529.

[0376] The control circuitry 540 is also configured to determine when a user is puffing on an aerosol-generating system comprising the aerosol-generating device 510. In this example, the aerosol-generating device 540 comprises a puff sensor (not shown), wherein the control circuitry 540 is configured to determine when a user is puffing on the aerosol-generating system based on information received from the puff sensor.

[0377] Figure 6 shows a cross-sectional view of an aerosol-generating system 6100 comprising the aerosol-generating device 510 of Figure 5, labelled here as 610 and an aerosol-generating article 6102.

[0378] The aerosol-generating article 6102 comprises an aerosol-generating section 6104 comprising an aerosol-generating substrate, a downstream section 6106 downstream of the aerosol-generating section 6104, and an upstream section 6108 upstream of the aerosolgenerating section 6104. The aerosol-generating article 6102 also comprises an internal heater in the form of a susceptor element 6114 arranged within the aerosol-generating section 6104. During use, a portion of the aerosol-generating article 6102 is inserted into the chamber 516 so that the aerosol-generating section 6104 and the susceptor element 6114 are positioned inside the heat-conducting element 628 and the inductor coil 624. The control circuitry 540 provides an alternating electric current from the power supply 542 to the inductor coil 624 to generate an alternating magnetic field that inductively heats the susceptor element 6114, which heats an inner portion of the aerosol-generating substrate in the aerosol-generating section 6104 to generate an aerosol. Additionally, heat generated in the inductor coil 624 itself by resistive losses in the inductor coil 624 may be conducted from the inductor coil 624 to an outer portion of the aerosolgenerating substrate in the aerosol-generating section 6104 by the heat-conducting element 628. The control circuitry 540 also provides a direct electric current from the power supply 542 to the heat-conducting element 628 to resistively heat the heat-conducting element 628. Advantageously, the direct contact between the cylindrical inner surface 523 of the heat-conducting element 628 and the aerosol-generating article 6102 facilitates the transfer of the resistively generated heat from the heat-conducting element 628 to the aerosol-generating article 6102. Advantageously, the smooth, curved plane formed by the cylindrical inner surface 523 of the heat conducting element 628 maximises a contact area between the heat-conducting element 628 and the aerosol-generating article 6102, which increases or maximises the transfer of heat from the heat-conducting element 628 to the aerosol-generating article 6102. Advantageously, the external heating provided by the resistively heated heat-conducting element 628 and the internal heating provided by the inductively heated susceptor element 6114 may facilitate aerosol generation across both the inner and outer portions of the aerosol-generating substrate in the aerosol-generating section 6104.

[0379] Airflow through the aerosol-generating system 6100 during use is illustrated by the dashed lines 6116 in Figure 6. When a user draws on a downstream end of the aerosol-generating article 6102, a negative pressure is generated in the chamber 516. The negative pressure draws air into the aerosol-generating device 610 through the air inlets 625. The air entering the air inlets 625 flows along the airflow passages 527 and into the common airflow passage 530 where it reaches the second end 520 of the chamber 516. The air entering the second end 520 of the chamber 516 then enters the aerosol-generating article 6102 through an upstream end of the aerosol-generating article 6102. As the airflow passes through the aerosol-generating section 6104, aerosol generated by heating of the aerosol-generating substrate is entrained in the airflow. The aerosol then flows along the length of the aerosol-generating article 6102 and through the downstream end of the aerosol-generating article 6102 to the user.

[0380] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term "about". Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ± 5 percent of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention.

Claims

- 45 -Claims:

1. An aerosol-generating article for use with an aerosol-generating device to generate an aerosol, the aerosol-generating article comprising:an aerosol-generating substrate,at least one wrapper defining the longitudinal surface of the aerosol-generating article extending between an upstream end of the aerosol-generating article and a downstream end of the aerosol-generating article, the longitudinal surface defining a generally cylindrical shape, a classification region provided on the at least one wrapper, the classification region comprising an identifier readable by a sensor of an aerosol-generating device,wherein the at least one wrapper comprises a tipping paper and a cigarette paper, the tipping paper extending to the downstream end of the aerosol-generating article, and the cigarette paper extending to the upstream end of the aerosol-generating article, the cigarette paper circumscribing the aerosol-generating substrate, andwherein the classification region is provided on the tipping paper.

2. An aerosol-generating article according to claim 1, wherein the classification region is provided as a band at least partially circumscribing the longitudinal surface of the aerosolgenerating article, the classification region extending longitudinally between an upstream end and a downstream end.

3. An aerosol-generating article according to any preceding claim, wherein the classification region does not overlay the aerosol-generating substrate.

4. An aerosol-generating article according to any preceding claim, wherein the classification region has a length between the upstream end of the classification region and the downstream end of the classification region of at least 0.5 millimetres, preferably at least 1 millimetre, more preferably at least 1.5 millimetres, still more preferably at least 2 millimetres.

5. An aerosol-generating article according to any preceding claim, wherein the classification region has a length between the upstream end of the classification region and the downstream end of the classification region of no more than 5 millimetres, preferably no more than 4.5 millimetres, more preferably no more than 4 millimetres, still more preferably no more than 3 millimetres.- 46 - 6. An aerosol-generating article according to any preceding claim, wherein the upstream end of the classification region is at least 15 millimetres from the upstream end of the aerosolgenerating article, preferably at least 17 millimetres from the upstream end of the aerosolgenerating article, more preferably at least 19 millimetres from the upstream end of the aerosolgenerating article.

7. An aerosol-generating article according to any preceding claim, wherein the upstream end of the classification region is at least 20 millimetres from the downstream end of the aerosolgenerating article, preferably at least 22 millimetres from the downstream end of the aerosolgenerating article, more preferably at least 25 millimetres from the downstream end of the aerosolgenerating article.

8. An aerosol-generating article according to any preceding claim, wherein the downstream end of the classification region is at least 15 millimetres from the downstream end of the aerosolgenerating article, preferably at least 20 millimetres from the downstream end of the aerosolgenerating article, more preferably at least 22 millimetres from the downstream end of the aerosolgenerating article.

9. An aerosol-generating article according to any preceding claim, wherein the downstream end of the classification region is at least 18 millimetres from the upstream end of the aerosolgenerating article, preferably at least 20 millimetres from the upstream end of the aerosolgenerating article, more preferably at least 22 millimetres from the upstream end of the aerosolgenerating article.

10. An aerosol-generating article according to any preceding claim, wherein the downstream end of the classification region is no more than 28 millimetres from the upstream end of the aerosol-generating article, preferably no more than 25 millimetres from the upstream end of the aerosol-generating article, more preferably no more than 23 millimetres from the upstream end of the aerosol-generating article.

11. An aerosol-generating article according to any preceding claim, wherein the identifier is provided on the outer surface of the at least one wrapper.

12. An aerosol-generating article according to any preceding claim, wherein the identifier comprises at least one coloured band fully circumscribing the longitudinal surface of the aerosolgenerating article, the at least one coloured band having a consistent colour extending around the full circumference of the longitudinal surface.- 47 -13. An aerosol-generating article according to claim 12, wherein the at least one coloured band has a length between an upstream end of the at least one coloured band and the downstream end of the at least one coloured band of at least 0.1 millimetres, preferably at least 0.25 millimetres, more preferably at least 0.5 millimetres.

14. An aerosol-generating device for use with an aerosol-generating article, the aerosolgenerating device comprising:a cavity for receiving at least a portion of the aerosol-generating article according to any preceding claim,a source of radiation arranged to irradiate a taggant of an aerosol-generating article when the aerosol-generating article is received within the cavity;a photodetector arranged to detect radiation emitted by a taggant of an aerosol-generating article when the aerosol-generating article is received within the cavity;a light sensor arranged to detect at least one colour of a coloured band of an aerosolgenerating article; anda power supply configured to supply power to the source of radiation, the photodetector, and the light sensor.

15. An aerosol-generating system for generating an aerosol, the aerosol-generating system comprising,an aerosol-generating device according to claim 14, andan aerosol-generating article according to any one of claims 1 to 13 received within the cavity.

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