EP4655233A1

EP4655233A1 - Aerosol-generating article material end detection by detection of difference between bobbin core and wound material

Info

Publication number: EP4655233A1
Application number: EP24702157.9A
Authority: EP
Inventors: Pietro Davide LA PORTA
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 2023-01-26
Filing date: 2024-01-26
Publication date: 2025-12-03
Also published as: WO2024156847A1; KR20250135884A; JP2026502664A; CN120641342A

Abstract

A system (1) for supplying a continuous material (3) for aerosol-generating articles includes a bobbin holder (5) and a bobbin exhaustion sensor (37). The bobbin holder (5) is configured to receive a supply bobbin (7) comprising a bobbin core (9) and a continuous material (3) wound around the bobbin core (9), such that the supply bobbin (7) is rotatable about a rotation axis (13) for unwinding the continuous material (3). The bobbin exhaustion sensor (37) is configured to monitor a monitoring region (39) through which a circumferential surface of the supply bobbin (7) passes, when the supply bobbin (7) is rotated about the rotation axis (13). The bobbin exhaustion sensor (37) is configured to determine whether a portion of the circumferential surface of the supply bobbin (7) located in the monitoring region (39) is formed by the continuous material (3) or by the bobbin core (9).

Description

Aerosol-generating Article Material End Detection by Detection of Difference between Bobbin Core and Wound Material

The present disclosure relates to supplying a continuous material, in particular a continuous material for aerosol-generating articles, by unwinding the continuous material from a bobbin core.

W02022058079A1 discloses to measure the decreasing diameter of a bobbin during its unwinding by means of one or more sensors. The sensor may be connected to a system able to trigger a change of bobbin, or a splice, when the bobbin diameter is below a predetermined threshold, which indicates that the bobbin has reached a predetermined depletion state.

EP3630661 B1 discloses a method of unwinding a bobbin of a coiled sheet of homogenized tobacco. The method includes sensing a diameter of the bobbin to detect when the bobbin needs to be replaced. Further, a roller having a rotation axis substantially parallel to the rotation axis of the bobbin is put in contact with the bobbin. While unwinding the sheet from the bobbin, the roller is kept in contact with an outer surface of the bobbin.

CN110642057B discloses a roll of material, where color mark positioning points are arranged at intervals on the surface layer, wherein when the radial color mark sensor detects the color mark positioning point, the automatic splicing mechanism splices a new roll material to the running roll material, and cuts off the remaining pattern material of the running roll.

According to an aspect of the present invention, there is provided a system for supplying a continuous material for aerosol-generating articles. The system comprises a bobbin holder and a bobbin exhaustion sensor. The bobbin holder is configured to receive a supply bobbin. The supply bobbin comprises a bobbin core and a continuous material wound around the bobbin core. The bobbin holder is configured to receive the supply bobbin such that the supply bobbin is rotatable around a rotation axis for unwinding the continuous material. The bobbin exhaustion sensor is configured to monitor a monitoring region through which a circumferential surface of the supply bobbin passes, when the supply bobbin is rotated about the rotation axis. The bobbin exhaustion sensor is configured to determine whether a portion of the circumferential surface of the supply bobbin located in the monitoring region is formed by the continuous material or by the bobbin core.

While at least a full turn of the continuous material remains on the bobbin core, the portion of the circumferential surface of the supply bobbin located in the monitoring region may be formed by the continuous material, irrespective of a rotation angle of the supply bobbin about the rotation axis. If less than a full turn of the continuous material remains on the bobbin core, the portion of the circumferential surface of the supply bobbin located in the monitoring region may be formed by the bobbin core, at least in some rotational angles of the supply bobbin about the rotation axis. As long as the bobbin exhaustion sensor determines that the portion of the circumferential surface of the supply bobbin located in the monitoring region continues to be formed by the continuous material during unwinding, this may be taken as an indication that there is still material, in particular at least one full turn of the continuous material, remaining on the bobbin core. If the bobbin exhaustion sensor determines during unwinding that the portion of the circumferential surface of the supply bobbin located in the monitoring region is formed by the bobbin core, this may be taken as an indication that less than a full turn of the continuous material remains on the bobbin core.

The bobbin exhaustion sensor may be configured to determine that less than a full turn of the continuous material remains on the bobbin core during unwinding of the continuous material.

The bobbin exhaustion sensor may be configured to detect when the portion of the circumferential surface of the supply bobbin located in the monitoring region ceases to be formed by the continuous material and starts to be formed by the bobbin core. This may be taken as indication that less than a full turn of the continuous material remains on the bobbin core.

A length of the continuous material that remains on the bobbin core, when the portion of the circumferential surface of the supply bobbin located in the monitoring region ceases to be formed by the continuous material and starts to be formed by the bobbin core during unwinding of the continuous material may correspond to a distance on a circumferential surface of the supply bobbin between the monitoring region and a point where the continuous material leaves the supply bobbin during unwinding. The length of the continuous material that remains on the bobbin core when the portion of the circumferential surface of the supply bobbin located in the monitoring region ceases to be formed by the continuous material and starts to be formed by the bobbin core during the unwinding may be less than a full turn of the continuous material on the bobbin core.

The bobbin exhaustion sensor may be configured to determine exhaustion of the supply bobbin with high accuracy.

The bobbin exhaustion sensor may be configured to determine when a length of the continuous material that remains on the supply bobbin falls below a predetermined threshold length. The predetermined threshold length may be a length of the continuous material corresponding to less than a full turn of the continuous material on the bobbin core.

The circumferential surface of the supply bobbin may extend in parallel to the rotation axis. The circumferential surface of the supply bobbin may extend around the rotation axis.

The system may further comprise a drive. The drive may be configured to unwind the continuous material from the supply bobbin by rotating the supply bobbin about the rotation axis. The drive may be part of the bobbin holder. The drive may be configured to engage the bobbin core to drive the bobbin core to rotate about the rotation axis. The system may comprise a controller. The controller may be configured to control the drive. The controller may be configured to control an unwinding speed.

The bobbin exhaustion sensor may be configured to carry out an optical measurement of the portion of the circumferential surface of the supply bobbin located in the monitoring region. The bobbin exhaustion sensor may be configured to determine based on the optical measurement whether the portion of the circumferential surface of the supply bobbin located in the monitoring region is formed by the continuous material or by the bobbin core.

The optical measurement may be a color measurement. The bobbin exhaustion sensor may be configured to determine a color of the portion of the circumferential surface of the supply bobbin located in the monitoring region. The bobbin exhaustion sensor or the controller may be configured to determine whether the determined color corresponds to a color range of the continuous material or to a color range of the bobbin core. One or both of the color range of the continuous material and the color range of the bobbin core may be preset. One or both of the color range of the continuous material and the color range of the bobbin core may be preset based on a kind of supply bobbin.

A color of the continuous material may be different from a color of the bobbin core. The bobbin core have a color that is sufficiently different from a color of the continuous material to facilitate distinguishing between the continuous material and the bobbin core. For example, if the continuous material is a reconstituted tobacco material having a brown color, the bobbin core may have a color different than brown, such as white, for example. In particular, the bobbin core may comprise a plastic material, in particular a white plastic material. According to another example, the continuous material may be a reconstituted tobacco material having a brown color and the bobbin core may be of a different kind of brown. For example, the bobbin core may comprise a cardboard material, in particular a brown cardboard material.

The bobbin exhaustion sensor may comprise a camera. The bobbin exhaustion sensor may be configured to obtain one or more photos of the monitoring region during the unwinding. The bobbin exhaustion sensor may be configured to obtain a video of the monitoring region during the unwinding. The video may be considered as a sequence of photos. The bobbin exhaustion sensor may be configured to analyze the one or more photos or the video to determine whether the portion of the circumferential surface of the supply bobbin located in the monitoring region is formed by the continuous material or by the bobbin core.

The bobbin exhaustion sensor may comprise a spectrophotometer. The spectrophotometer may be configured to conduct a color measurement in the monitoring region.

The system, in particular one or both of the controller and the drive, may be configured to slow or stop unwinding the continuous material in response to the bobbin exhaustion sensor detecting that the portion of the circumferential surface of the supply bobbin located in the monitoring area is formed by the bobbin core. Slowing or stopping unwinding the continuous material may prepare for replacing the exhausted supply bobbin. Slowing or stopping unwinding the continuous material may prevent that an end of the continuous material is fully withdrawn from the bobbin core during continuous operation. The system, in particular one or both of the controller and the drive, may be configured to stop unwinding the continuous material sufficiently fast that the end of the continuous material remains on the bobbin core.

The system may further comprise a slicing unit. The splicing unit may be configured to splice the continuous material with continuous material from a replacement supply bobbin. The system, in particular the controller or the bobbin exhaustion sensor, may initiate splicing in response to the bobbin exhaustion sensor detecting that the portion of the circumferential surface of the supply bobbin located in the monitoring area is formed by the bobbin core. If splicing is initiated based on information from the bobbin exhaustion sensor, waste of material may be reduced, since less than a full turn of the continuous material remains on the bobbin core.

The splicing unit may be provided along a transport path of the continuous material downstream of the bobbin holder.

Any splicing known in the art that connects, preferably stably connects, two continuous materials may be used in the present invention. The splicing unit may comprise a first tool and a second tool. The first tool may be a lower tool. The second tool may be an upper tool. The first tool and the second tool may be configured to interact to splice the continuous material from the supply bobbin and the continuous material from the replacement supply bobbin between each other. Splicing may comprise pressing the continuous material from the supply bobbin and the continuous material from the replacement supply bobbin against each other in an overlap portion. The continuous material from the supply bobbin and the continuous material from the replacement supply bobbin may be positioned overlapping and in parallel to each other between the first tool and the second tool. The continuous material from the supply bobbin and the continuous material from the replacement supply bobbin may be positioned above each other between the first tool and the second tool.

The system may be configured to convey the continuous material from the supply bobbin through the splicing unit, in particular through a space between the first tool and the second tool of the splicing unit. The system may be configured to convey the continuous material from the supply bobbin through the splicing unit to a processing location.

The system may comprise a positioning mechanism. The positioning mechanism may be configured to move a leading portion of the continuous material from the replacement supply bobbin into the splicing unit or through the splicing unit, in particular into a space between the first tool and the second tool of the splicing unit or through a space between the first tool and the second tool of the splicing unit. The positioning mechanism may comprise a robot arm, for example.

Splicing may comprise wetting one or both of the continuous material of the supply bobbin and the continuous material of the replacement supply bobbin. Wetting may increase a tendency of the materials to stick together. In particular, splicing may comprise wetting the continuous material in the form of reconstituted tobacco material.

In some embodiments, particularly when the continuous material may comprise a metal material or may consist of metal, the splicing unit may comprise a welding station. The welding station may comprise at least one welding electrode and a welding plate. The at least one welding electrode and the welding plate may be arranged at opposite upper and lower sides of the continuous material in an orthogonal direction.

After splicing, the system may continue to provide a stream of continuous material, but now from the replacement supply bobbin.

The system may further comprise a counter structure. The counter structure may be configured to press the continuous material towards the bobbin core. The counter structure may be configured to press the continuous material towards the bobbin core along a radial direction.

The counter structure may be configured to press the continuous material towards the bobbin core after the bobbin exhaustion sensor has detected that the portion of the circumferential surface of the supply bobbin located in the monitoring area is formed by the bobbin core. Pressing the continuous material towards the bobbin core by the counter structure may maintain tension of the continuous material. Pressing the continuous material towards the bobbin core by the counter structure may prevent a remaining end portion of the continuous material from disengaging from the bobbin core. The counter structure may be configured to press the continuous material towards the bobbin core during splicing. The counter structure may be configured to press the continuous material towards the bobbin core to facilitate splicing.

According to an embodiment, the counter structure may be configured to contact the supply bobbin only after the exhaustion sensor has determined that the portion of the circumferential surface of the supply bobbin located in the monitoring region is formed by the bobbin core, or after a determination that the supply bobbin is exhausted or approaching exhaustion.

The counter structure may be configured to press the continuous material towards the bobbin core during unwinding of the continuous material. The counter structure may be configured to press the continuous material towards the bobbin core before the bobbin exhaustion sensor has detected that the portion of the circumferential surface of the supply bobbin located in the monitoring area is formed by the bobbin core. The counter structure may be configured to press the continuous material towards the bobbin core both before and after the bobbin exhaustion sensor has detected that the portion of the circumferential surface of the supply bobbin located in the monitoring area is formed by the bobbin core.

The counter structure may be configured to press the continuous material towards the bobbin core with a first pressing force before the bobbin exhaustion sensor has detected that the portion of the circumferential surface of the supply bobbin located in the monitoring area is formed by the bobbin core. The counter structure may be configured to press the continuous material towards the bobbin core with a second pressing force after the bobbin exhaustion sensor has detected that the portion of the circumferential surface of the supply bobbin located in the monitoring area is formed by the bobbin core. The first pressing force and the second pressing force may be of at least essentially the same magnitude. The second pressing force may be greater than the first pressing force. The smaller first pressing force may facilitate unwinding of the continuous material. The greater second pressing force may facilitate splicing by maintaining tension in the continuous material.

The counter structure may be configured to clamp the continuous material against the bobbin core. Clamping the continuous material against the bobbin core may reduce or prevent relative movement between the continuous material and the bobbin core. The counter structure may be configured to clamp the continuous material towards the bobbin core after the bobbin exhaustion sensor has detected that the portion of the circumferential surface of the supply bobbin located in the monitoring area is formed by the bobbin core or in response to the exhaustion sensor detecting that the portion of the circumferential surface of the supply bobbin located in the monitoring area is formed by the bobbin core.

The counter structure may be configured to be in contact with the continuous material wound around the bobbin core. The counter structure may be configured to remain in contact with the continuous material wound around the bobbin core during the unwinding. The counter structure may be configured to follow a decreasing diameter of the supply bobbin during the unwinding. The counter structure may be configured to follow the diameter of the supply bobbin by moving along a radial direction during the unwinding.

The counter structure may define a position where the continuous material disengages from the supply bobbin. The counter structure may guide the continuous material disengaging from the supply bobbin during the unwinding. The counter structure may comprise a counter roll. An axial direction of the counter roll may be parallel to the rotation axis. A circumferential surface of the counter roll may be parallel to the rotation axis. A circumferential surface of the counter roll may be parallel to the rotation axis. A circumferential surface of the counter roll may be configured to engage the continuous material. The system may further comprise a thickness sensor. The thickness sensor may be configured to determine a thickness of the supply bobbin. The thickness of the supply bobbin determined by the thickness sensor may indicate a length of the continuous material that remains on the bobbin core. The thickness of the supply bobbin may correspond to a diameter of the supply bobbin. The thickness of the supply bobbin may be a thickness in a radial direction perpendicular to the rotation axis. The thickness sensor may provide an estimation of a length of the continuous material that remains on the bobbin core even though the length is more than a full turn of the continuous material around the bobbin core.

The thickness sensor and the bobbin exhaustion sensor may complement each other. The thickness sensor may provide a rougher estimate of a length of the continuous material that remains on the supply bobbin at any arbitrary stage of the unwinding. The bobbin exhaustion sensor may provide a more accurate estimation of a length of the continuous material that remains on the supply bobbin, but only when less than a full turn of the continuous material remains on the supply bobbin.

The thickness sensor may be configured to measure a distance between the thickness sensor and the circumferential surface of the supply bobbin. The distance may be along a radial direction perpendicular to the rotation axis. When the length of the continuous material that remains on the supply bobbin decreases during unwinding, the distance between the thickness sensor and the circumferential surface of the supply bobbin may increase due to a decrease in the diameter of the supply bobbin.

The thickness sensor may be configured to determine the thickness of the supply bobbin based on a position of the counter structure. The counter structure may follow a decreasing diameter of the supply bobbin during the unwinding. Thus, the position of the counter structure may be indicative of a thickness of the supply bobbin. The thickness sensor may comprise a distance sensor sensing a distance between the distance sensor and the counter structure. The thickness sensor may be configured to determine a position of the counter structure along a guide structure for the counter structure. The guide structure may be configure to guide the counter structure for movement along a radial direction.

The system, in particular one of both of the controller and the drive, may optionally be configured to slow unwinding the continuous material in response to a thickness of the supply bobbin measured by the thickness sensor being below a predetermined threshold thickness. Slowing unwinding of the continuous material when the thickness of the supply bobbin falls below the predetermined threshold thickness may prepare for stopping the unwinding when the bobbin exhaustion sensor determines that the portion of the circumferential surface of the supply bobbin located in the monitoring region is formed by the bobbin core. At the predetermined threshold thickness, a length of the continuous material that corresponds to at least some full turns of the continuous material around the bobbin core may remain on the bobbin core. For example, at least three full turns, or at least five full turns, or at least seven full turns, or at least ten full turns, or at least 15 full turns, or at least 20 full turns, or at least 30 full turns, or at least 50 full turns, or at least 70 full turns, or at least 100 full turns of the continuous material may remain on the supply bobbin at the predetermined threshold thickness. Less than 1000 full turns, or less than 600 full turns, or less than 400 full turns, or less than 300 full turns, or less than 200 full turns, or less than 100 full turns, or less than 50 full turns, or less than 30 full turns, or less than ten full turns may remain on the supply bobbin at the predetermined threshold thickness.

Slowing unwinding the continuous material in response to the thickness of the supply bobbin measured by the thickness sensor being below a predetermined threshold thickness may comprise slowing unwinding the continuous material from an operating unwinding speed to an intermediate unwinding speed. The intermediate unwinding speed may be greater than zero. The operating unwinding speed may, for example, be between 20 m/min (meters per minute) and 400 m/min, or between 50 m/min and 400 m/min, or between 50 m/min and 300 m/min, or between 80 m/min and 300 m/min, or between 80 m/min and 250 m/min, or between 100 m/min and 250 m/min, or between 120 m/min and 200 m/min. The intermediate unwinding speed may, for example, be between 10 m/min and 200 m/min, or between 10 m/min and 150 m/min, or between 10 m/min and 100 m/min, or between 20 m/min and 80 m/min, or between 40 m/min and 60 m/min. The intermediate unwinding speed may be between 10 percent and 60 percent, or between 20 percent and 50 percent, or between 20 percent and 30 percent of the operation unwinding speed.

The system may further comprise the supply bobbin. The supply bobbin may be received in the bobbin holder.

The continuous material may be provided free of a fixed connection to the bobbin core.

The system may comprise a processing station. The processing station may be provided at a processing location. The processing station may be configured to process the continuous material. The processing station may be provided downstream of the bobbin holder. The processing station may be configured to receive the continuous material unwound from the supply bobbin. The system may be configured to convey the unwound continuous material to the processing station.

The processing station may, for example, comprise a crimping station. The crimping station may be configured to crimp the continuous material, in particular continuous material in the form of reconstituted tobacco material. The crimping station may comprise one or more crimping rollers. The one or more crimping rollers may be configured to create creases in the continuous material. The one or more crimping rollers may be configured to create weakened portions in the continuous material. The creases or weakened portions may extend in parallel to a transport direction of the continuous material.

According to another aspect of the present invention, there is provided a method of supplying a continuous material for aerosol-generating articles to a processing location. The method comprises unwinding a continuous material from a supply bobbin. The supply bobbin comprises a bobbin core and the continuous material wound around the bobbin core. The method comprises conveying the unwound continuous material to a processing location. The method further comprises detecting exhaustion of the supply bobbin by detecting a difference between a surface of the continuous material and a surface of the bobbin core.

The supply bobbin may be received in a bobbin holder.

Unwinding the continuous material from the supply bobbin may comprise rotating the supply bobbin about a rotation axis, in particular by a drive.

The surface of the bobbin core may be a circumferential surface of the bobbin core. The circumferential surface of the bobbin core may be parallel to the rotation axis.

The detecting the difference between the surface of the continuous material and the surface of the bobbin core may be carried out by a bobbin exhaustion sensor.

Detecting exhaustion of the supply bobbin may comprise monitoring, in particular monitoring by a bobbin exhaustion sensor, a monitoring region through which a circumferential surface of the supply bobbin passes, when the supply bobbin is rotated about the rotation axis. Detecting exhaustion of the supply bobbin may comprise determining, in particular determining by the bobbin exhaustion sensor, whether a portion of the circumferential surface of the supply bobbin located in the monitoring region is formed by the continuous material or by the bobbin core.

The supply bobbin may be considered as exhausted, if less than one full turn of the continuous material remains on the bobbin core.

Detecting a difference between the surface of the continuous material and the surface of the bobbin core may comprise detecting that the bobbin core becomes revealed, when less than a full turn of the continuous material remains on the bobbin core.

The method may comprise determining exhaustion of the supply bobbin, when a portion of the circumferential surface of the supply bobbin that is formed by the continuous material as long as at least one full turn of the continuous material remains on the supply bobbin is no longer formed by the continuous material, but by the bobbin core.

The detecting the difference between the surface of the continuous material and the surface of the bobbin core may comprise taking one or more pictures or one or more videos of a circumferential surface of the supply bobbin. The detecting the difference between the surface of the continuous material and the surface of the bobbin core may comprise detecting a color difference between the surface of the continuous material and the surface of the bobbin core. The color difference may be determined by analyzing one or more photos or one or more videos of a circumferential surface of the supply bobbin. The color difference may be detected based on a measurement by a camera or a spectrophotometer.

Detecting exhaustion of the supply bobbin may comprise detecting a border between a portion of a circumferential surface of the bobbin core that is covered by the continuous material and a portion of a circumferential surface of the bobbin core that is not covered by the continuous material. The border may correspond to an end of the continuous material. The end of the continuous material may be an end of the continuous material with respect to a conveying direction of the continuous material. The end of the continuous material may be the part of the continuous material that is last to leave the bobbin core, if the entirety of the continuous material is unwound from the bobbin core.

The border may extend generally in parallel to a rotation axis of the bobbin core.

The method may further comprise slowing or stopping, in particular by one or both of the drive or the controller, one or both of unwinding the continuous material and conveying the unwound continuous material in response to detecting that the supply bobbin is exhausted.

The method may comprise initiating splicing of the continuous material with continuous material from a replacement supply bobbin in response to detecting that the supply bobbin is exhausted. Splicing may be carried out by a splicing station. Splicing may comprise attaching a leading portion of the continuous material from the replacement supply bobbin to the continuous material of the supply bobbin. The continuous materials may be attached to each other by pressing the continuous materials together. Splicing may comprise wetting one or both of the continuous material from the supply bobbin and the continuous material from the replacement supply bobbin. For example, continuous material in the form of reconstituted tobacco material from one or both of the supply bobbin and the replacement supply bobbin may be wetted to increase a tendency of the continuous material from the supply bobbin and the continuous material from the replacement supply bobbin to stick together. Splicing may comprise heating one or both of the continuous material from the supply bobbin and the continuous material from the replacement supply bobbin. For example, heating continuous material comprising metal, such as a susceptor configured to be incorporated in an aerosol-generating article, may facilitate bonding the continuous material of the supply bobbin to the continuous material from the replacement supply bobbin.

The method may comprise pressing or clamping the continuous material against the bobbin core. The method may comprise pressing or clamping the continuous material towards the bobbin core. The continuous material may be pressed or clamped against or towards the bobbin core after exhaustion of the supply bobbin has been detected. The continuous material may be pressed or clamped against or towards the bobbin core in response to detection of exhaustion of the bobbin core. Pressing or clamping the continuous material against or towards the bobbin core may maintain tension of the continuous material downstream of the supply bobbin, in particular to facilitate splicing.

In addition or as an alternative to pressing or clamping the continuous material against or towards the bobbin core after exhaustion of the supply bobbin has been detected, the continuous material may be pressed or clamped towards the bobbin core even before exhaustion of the supply bobbin has been detected. In particular, the continuous material may be pressed in the direction of the bobbin core during the entire unwinding.

The continuous material may be pressed or clamped against the bobbin core by a counter structure.

The counter structure may follow a decreasing diameter of the supply bobbin during the unwinding.

A thickness of the supply bobbin may be determined based on a position of the counter structure. The counter structure may have a double function of pressing or clamping the continuous material towards the bobbin core and facilitating determining a thickness of the supply bobbin. The thickness of the supply bobbin may be determined based on a position of the counter structure along a guide structure guiding the counter structure, in particular guiding the counter structure for a motion along a radial direction.

The counter structure may comprise a counter roll. An axial direction of the counter roll may extend in parallel to a rotation axis of the supply bobbin. The counter roll may define where the continuous material leaves the supply bobbin during the unwinding.

The method may comprise determining a thickness of the supply bobbin during the unwinding. The thickness of the supply bobbin may correspond to a diameter of the supply bobbin.

The thickness of the supply bobbin may be determined by a thickness sensor. The thickness sensor may measure a distance between the thickness sensor and the circumferential surface of the supply bobbin. The distance between the thickness sensor and the circumferential surface of the supply bobbin may increase during the unwinding due to a reduction in the diameter of the supply bobbin.

The thickness of the supply bobbin may be determined based on the position of a counter structure in contact with the continuous material wound around the bobbin core and following a decreasing diameter of the supply bobbin during the unwinding. The counter structure may be a counter roll. The method may comprise reducing a rotational speed of the supply bobbin during the unwinding in response to determining, in particular in response to determining by the thickness sensor, that a thickness of the supply bobbin has fallen below a predetermined threshold thickness.

The reducing the rotational speed of the supply bobbin during the unwinding in response to determining that the thickness of the supply bobbin has fallen below a predetermined threshold thickness may comprise reducing rotational speed of the supply bobbin from an operating unwinding speed to an intermediate unwinding speed. The intermediate rotational speed may be greater than zero.

According to another aspect of the present invention, there is provided a use of a color measurement device for determining whether a supply bobbin is exhausted during unwinding a continuous material from the supply bobbin.

The color measurement device may be part of a bobbin exhaustion sensor or may form a bobbin exhaustion sensor.

The color measurement device may determine whether a portion of a circumferential surface of the supply bobbin located in a monitoring region through which a circumferential surface of the supply bobbin passes during the unwinding is formed by the continuous material or by a bobbin core of the supply bobbin.

The color measurement device may be configured to detect exhaustion of the supply bobbin by detecting a difference between a surface of the continuous material and a surface of the bobbin core of the supply bobbin.

According to another aspect of the present invention, there is provided a system for supplying a continuous material for aerosol-generating articles. The system comprises a bobbin holder, a counter structure, and a thickness sensor. The bobbin holder is configured to receive a supply bobbin such that the supply bobbin is rotatable about a rotation axis. The supply bobbin comprises a bobbin core and a continuous material wound around the bobbin core. The counter structure is configured to be in contact with the continuous material wound around the bobbin core. The counter structure is configured to follow a decreasing diameter of the supply bobbin during the unwinding. The thickness sensor is configured to determine a thickness of the supply bobbin based on a position of the counter structure.

The system may comprise a drive. The drive may be configured to unwind the continuous material from the supply bobbin by rotating the supply bobbin about the rotation axis.

The system may comprise a controller. The controller may be configured to control the drive. The counter structure may be configured to follow the diameter of the supply bobbin by moving along a radial direction during the unwinding.

The system may comprise a guide structure. The guide structure may be configured to guide the counter structure for moving along the radial direction.

The thickness sensor may comprise a distance sensor sensing a distance between the distance sensor and the counter structure.

The thickness sensor may be configured to measure or determine a position of the counter structure with respect a movement of the counter structure along the radial direction as guided by the guide structure.

The counter structure may be configured to press the continuous material towards the bobbin core. The counter structure may be configured to press the continuous material towards the bobbin core during unwinding of the continuous material. The counter structure may be configured to press the continuous material towards the bobbin core along a radial direction.

The counter structure may define a position where the continuous material leaves the supply bobbin upon unwinding of the continuous material. The counter structure may stabilize the continuous material during unwinding. The counter structure may guide the continuous material disengaging from the supply bobbin during the unwinding.

The counter structure may be configured to clamp the continuous material against the bobbin core.

The counter structure may comprise a counter roll.

The system, in particular one or both of the controller and the drive, may be configured to slow unwinding the continuous material in response to the thickness of the supply bobbin determined by the thickness sensor being below a predetermined threshold thickness.

The system may comprise a bobbin exhaustion sensor. The bobbin exhaustion sensor may be configured to monitor a monitoring region through which a circumferential surface of the supply bobbin passes when the supply bobbin is rotated about the rotation axis.

The bobbin exhaustion sensor may be configured to determine whether a portion of the circumferential surface of the supply bobbin located in the monitoring region is formed by the continuous material or by the bobbin core.

According to another aspect of the present invention, there is provided a method of supplying a continuous material for aerosol-generating articles to a processing location. The method comprises unwinding a continuous material from a supply bobbin. The supply bobbin comprises a bobbin core and the continuous material wound around the bobbin core. The method further comprises conveying the unwound continuous material to a processing location. The method further comprises determining a thickness of the supply bobbin based on a position of a counter structure in contact with the continuous material wound around the bobbin core and following a decreasing diameter of the supply bobbin during the unwinding.

The continuous material may be pressed or clamped against the bobbin core by the counter structure during the unwinding.

The counter structure may comprise a counter roll.

The method may comprise reducing a rotational speed of the supply bobbin during the unwinding in response to determining that the thickness of the supply bobbin has fallen below a predetermined threshold thickness.

The method may further comprise detecting exhaustion of the supply bobbin by detecting a difference between a surface of the continuous material and a surface of the bobbin core.

According to another aspect of the present invention, there is provided a use of a counter structure to press the continuous material against a bobbin core and to determine a thickness of a supply bobbin comprising the bobbin core and the continuous material wound around the bobbin core during unwinding a continuous material from the supply bobbin.

According to any one of the aspects described herein, the continuous material may comprise an aerosol-generating material. The aerosol-generating material may be configured to release an aerosol upon being heated. The aerosol may be an aerosol for consumption by a user. The aerosol-generating material may comprise tobacco. The aerosol-generating material may comprise a reconstituted tobacco material.

In any one of the aspects described herein, the continuous material may be a web material. The web material may, for example, comprise reconstituted tobacco material.

In any one of the aspects described herein, the continuous material may comprise reconstituted tobacco material. The reconstituted tobacco material may be a cast of a slurry comprising tobacco material. The reconstituted tobacco material may comprise a binder. The reconstituted tobacco material may comprise an aerosol former. The reconstituted tobacco material may comprise one or more flavourants.

In any one of the aspects described herein, the continuous material may comprise a metal material or may consist of metal.

In any one of the aspects described herein, the continuous material may comprise a metal strand.

In any one of the aspects described herein, the continuous material may comprise a susceptor configured to be incorporated in an aerosol-generating article. The susceptor may comprise a metal material or may consist of a metal material. The susceptor may be configured to be heated by induction heating. The susceptor may be configured to heat an aerosol-generating material surrounding the susceptor to cause the aerosol-generating material to release an aerosol. In any one of the aspects described herein, the aerosol-generating article may be an essentially stick-shaped or rod-shaped article. The aerosol-generating article may comprise a plurality of segments arranged one behind the other. The segments may be cylinder-shaped segments arranged one behind the other along their longitudinal axis. The segments may be combined with one or more wrappers wrapped around the segments. The segments may comprise an aerosol-generating segment. The aerosol-generating segment may comprise an aerosolgenerating material configured to release aerosol upon being heated. The aerosol-generating material may comprise tobacco. The segments may comprise a filter segment. Aerosol generated by heating the aerosol-generating segment may pass through the filter segment before reaching the mouth of a user. The segments may comprise a mouthpiece segment. The mouthpiece segment may be configured to be contacted by the mouth of a user. Alternatively, the filter segment may be engaged by the mouth of the user.

The aerosol-generating article may be configured to be used with an aerosol-generating device. The aerosol-generating article may be configured to be at least partially inserted into the aerosol-generating device. The aerosol-generating device may be configured to heat the aerosolgenerating article to release an aerosol from the aerosol-generating article. The aerosolgenerating device may be a handheld electronic device.

The present disclosure comprises various aspects, embodiments, and examples. Features, advantages, and explanations disclosed with reference to any one of these aspects, embodiments, and examples may be combined with, or transferred to, any other one of the aspects, embodiments, and examples described herein. Any one of the methods or uses described herein may be carried out using any one of the systems described herein. Any one of the systems described herein may be adapted, designed or configured to carry out any one of the methods and uses described herein.

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

Example Ex1 : System for supplying a continuous material for aerosol-generating articles, comprising: a bobbin holder configured to receive a supply bobbin comprising a bobbin core and a continuous material wound around the bobbin core, such that the supply bobbin is rotatable about a rotation axis for unwinding the continuous material; and a bobbin exhaustion sensor configured to monitor a monitoring region through which a circumferential surface of the supply bobbin passes, when the supply bobbin is rotated about the rotation axis; wherein the bobbin exhaustion sensor is configured to determine whether a portion of the circumferential surface of the supply bobbin located in the monitoring region is formed by the continuous material or by the bobbin core.

Example Ex2: System according to Example Ex1 , further comprising: a drive configured to unwind the continuous material from the supply bobbin by rotating the supply bobbin about the rotation axis; and a controller configured to control the drive.

Example Ex3: System according to Example Ex1 or Ex2, wherein the bobbin exhaustion sensor is configured to carry out an optical measurement of the portion of the circumferential surface of the supply bobbin located in the monitoring region.

Example Ex4: System according to Example Ex3, wherein the optical measurement is a color measurement.

Example Ex5: System according to any one of Examples Ex1 to Ex4, wherein the system is configured to slow or stop unwinding the continuous material in response to the bobbin exhaustion sensor detecting that the portion of the circumferential surface of the supply bobbin located in the monitoring area is formed by the bobbin core.

Example Ex6: System according to any one of Examples Ex1 to Ex5, further comprising a splicing unit configured to splice the continuous material with continuous material from a replacement supply bobbin, wherein the system initiates splicing in response to the bobbin exhaustion sensor detecting that the portion of the circumferential surface of the supply bobbin located in the monitoring area is formed by the bobbin core.

Example Ex7: System according to any one of Examples Ex1 to Ex6, further comprising a counter structure configured to press the continuous material towards the bobbin core.

Example Ex8: System according to Example Ex7, wherein the counter structure is configured to clamp the continuous material against the bobbin core.

Example Ex9: System according to Example Ex7 or Ex8, wherein the counter structure is configured to be in contact with the continuous material wound around the bobbin core and to follow a decreasing diameter of the supply bobbin during the unwinding.

Example Ex10: System according to any one of Examples Ex7 to Ex9, wherein the counter structure is configured to follow the diameter of the supply bobbin by moving along a radial direction during the unwinding.

Example Ex11 : System according to any one of Examples Ex7 to Ex10, wherein the counter structure comprises a counter roll. Example Ex12: System according to any one of Examples Ex1 to Ex11 , further comprising a thickness sensor configured to determine a thickness of the supply bobbin, in particular based on a position of the counter structure.

Example Ex13: System according to Example Ex12, wherein the thickness sensor is configured to measure a distance between the thickness sensor and the circumferential surface of the supply bobbin.

Example Ex14: System according to Example Ex12 or Ex13, wherein the system is configured to slow unwinding the continuous material in response to the thickness of the supply bobbin measured by the thickness sensor being below a predetermined threshold thickness.

Example Ex15: System according to any one of Examples Ex1 to Ex14, further including the supply bobbin.

Example Ex16: System according to any one of Examples Ex1 to Ex15, wherein the supply bobbin is received in the bobbin holder.

Example Ex17: System according to any one of Examples Ex1 to E16, wherein the continuous material is provided free of a fixed connection to the bobbin core.

Example Ex18: Method of supplying a continuous material for aerosol-generating articles to a processing location, the method comprising:

- unwinding a continuous material from a supply bobbin, wherein the supply bobbin comprises a bobbin core and the continuous material wound around the bobbin core;

- conveying the unwound continuous material to a processing location; and

- detecting exhaustion of the supply bobbin by detecting a difference between a surface of the continuous material and a surface of the bobbin core.

Example Ex19: Method according to Example Ex18, wherein the supply bobbin is exhausted, if less than one full turn of the continuous material remains on the bobbin core.

Example Ex20: Method according to Example Ex18 or Ex19, wherein the surface of the bobbin core is a circumferential surface of the bobbin core.

Example Ex21 : Method according to any one of Examples Ex18 to Ex20, wherein the detecting the difference between the surface of the continuous material and the surface of the bobbin core comprises detecting a color difference between the surface of the continuous material and the surface of the bobbin core.

Example Ex22: Method according to any one of Examples Ex18 to Ex21 , wherein the detecting exhaustion of the supply bobbin comprises detecting a border between a portion of a circumferential surface of the bobbin core that is covered by the continuous material and a portion of a circumferential surface of the bobbin core that is not covered by the continuous material. Example Ex23: Method according to Example Ex22, wherein the border extends generally in parallel to a rotation axis of the bobbin core.

Example Ex24: Method according to any one of Examples Ex18 to Ex23, further comprising slowing or stopping one or both of unwinding the continuous material and conveying the unwound continuous material in response to detecting that the supply bobbin is exhausted.

Example Ex25: Method according to any one of Examples Ex18 to Ex24, further comprising initiating splicing of the continuous material with continuous material from a replacement supply bobbin in response to detecting that the supply bobbin is exhausted.

Example Ex26: Method according to any one of Examples Ex18 to Ex25, further comprising pressing or clamping the continuous material against the bobbin core.

Example Ex27: Method according to any one of Examples Ex18 to Ex26, wherein the continuous material is pressed or clamped against the bobbin core by a counter structure.

Example Ex28: Method according to Example Ex27, wherein the counter structure follows a decreasing diameter of the supply bobbin during the unwinding.

Example Ex29: Method according to Example Ex27 or Ex28, wherein a thickness of the supply bobbin is determined based on a position of the counter structure during the unwinding.

Example Ex30: Method according to any one of Examples Ex27 to Ex29, wherein the counter structure comprises a counter roll.

Example Ex31 : Method according to any one of Examples Ex18 to Ex30, further comprising determining a thickness of the supply bobbin during the unwinding.

Example Ex32: Method according to any one of Examples Ex18 to Ex31 , wherein the thickness of the supply bobbin is determined by a thickness sensor measuring a distance between the thickness sensor and a circumferential surface of the supply bobbin.

Example Ex33: Method according to any one of Examples Ex18 to Ex32, wherein the thickness of the supply bobbin is determined based on a position of a counter structure in contact with the continuous material wound around the bobbin core and following a decreasing diameter of the supply bobbin during the unwinding.

Example Ex34: Method according to Example to Ex33, wherein the counter structure is the counter structure of any one of examples Ex27 to30.

Example Ex35: Method according to any one of Examples Ex18 to Ex34, further comprising reducing a rotational speed of the supply bobbin during the unwinding in response to determining that a thickness of the supply bobbin has fallen below a predetermined threshold thickness.

Example Ex36: Method according to Example Ex35, wherein the reducing the rotational speed of the supply bobbin during the unwinding in response to determining that the thickness of the supply bobbin has fallen below a predetermined threshold thickness comprises reducing the rotational speed of the supply bobbin to a rotational speed greater than zero.

Example Ex37: Use of a color measurement device for determining whether a supply bobbin is exhausted during unwinding a continuous material from the supply bobbin.

Example Ex38: System for supplying a continuous material for aerosol-generating articles, comprising: a bobbin holder configured to receive a supply bobbin such that the supply bobbin is rotatable about a rotation axis, the supply bobbin comprising a bobbin core and a continuous material wound around the bobbin core; a counter structure configured to be in contact with the continuous material wound around the bobbin core and to follow a decreasing diameter of the supply bobbin during the unwinding; and a thickness sensor configured to determine a thickness of the supply bobbin based on a position of the counter structure.

Example Ex39: System according to Example Ex38, further comprising: a drive configured to unwind the continuous material from the supply bobbin by rotating the supply bobbin about the rotation axis; and a controller configured to control the drive.

Example Ex40: System according to Example Ex38 or Ex39, wherein the counter structure is configured to follow the diameter of the supply bobbin by moving along a radial direction during the unwinding.

Example Ex41 : System according to any one of Examples Ex38 to Ex40, wherein the counter structure is configured to press the continuous material towards the bobbin core.

Example Ex42: System according to any one of Examples Ex38 to Ex41 , wherein the counter structure is configured to clamp the continuous material against the bobbin core.

Example Ex43: System according to any one of Examples Ex38 to Ex42, wherein the counter structure comprises a counter roll.

Example Ex44: System according to any one of Examples Ex38 to Ex43, wherein the system is configured to slow unwinding the continuous material in response to the thickness of the supply bobbin determined by the thickness sensor being below a predetermined threshold thickness.

Example Ex45: System according to any one of Examples Ex38 to Ex44, further comprising a bobbin exhaustion sensor configured to monitor a monitoring region through which a circumferential surface of the supply bobbin passes, when the supply bobbin is rotated about the rotation axis. Example Ex46: System according to Example to Ex45, wherein the bobbin exhaustion sensor is configured to determine whether a portion of the circumferential surface of the supply bobbin located in the monitoring region is formed by the continuous material or by the bobbin core.

Example Ex47: Method of supplying a continuous material for aerosol-generating articles to a processing location, the method comprising:

- conveying the unwound continuous material to a processing location; and

- determining a thickness of the supply bobbin based on a position of a counter structure in contact with the continuous material wound around the bobbin core and following a decreasing diameter of the supply bobbin during the unwinding.

Example Ex48: Method according to Example Ex47, wherein the continuous material is pressed or clamped against the bobbin core by the counter structure during the unwinding.

Example Ex49: Method according to Example Ex47 or Ex48, wherein the counter structure comprises a counter roll.

Example Ex50: Method according to any one of Examples Ex47 to Ex49, further comprising reducing a rotational speed of the supply bobbin during the unwinding in response to determining that the thickness of the supply bobbin has fallen below a predetermined threshold thickness.

Example Ex51 : Method according to any one of Examples Ex47 to Ex50, further comprising detecting exhaustion of the supply bobbin by detecting a difference between a surface of the continuous material and a surface of the bobbin core.

Example Ex52: Use of a counter structure to press a continuous material against a bobbin core and to determine a thickness of a supply bobbin comprising the bobbin core and the continuous material wound around the bobbin core during unwinding the continuous material from the supply bobbin.

Example Ex53: System, method or use according to any one of Examples Ex1 to Ex52, wherein the continuous material comprises an aerosol-generating material.

Example Ex54: System, method or use according to any one of Examples Ex1 to Ex53, wherein the continuous material is a web material.

Example Ex55: System, method or use according to any one of Examples Ex1 to Ex54, wherein the continuous material comprises reconstituted tobacco material.

Example Ex56: System, method or use according to any one of Examples Ex1 to Ex52, wherein the continuous material comprises a metal material. Example Ex57: System, method or use according to any one of Examples Ex1 to Ex52, wherein the continuous material comprises a metal strand.

Example Ex58: System, method or use according to any one of Examples Ex1 to Ex57, wherein the continuous material comprises a susceptor configured to be incorporated in an aerosol-generating article.

Examples will now be further described with reference to the figures in which:

Figure 1 shows a schematic side view of a system for supplying a continuous material according to an embodiment;

Figure 2 shows a perspective schematic view of a supply roll and a bobbin exhaustion sensor of the system according to the embodiment;

Figure 3 shows a schematic diagram indicating an unwinding speed on the vertical axis and a time on the horizontal axis according to the embodiment; and

Figure 4 shows a sequence of schematic representations of the supply bobbin and a counter structure of the system according to the embodiment, wherein a diameter of the supply bobbin decreases throughout the series.

Figure 1 shows a schematic side view of a system 1 for supplying a continuous material 3. The system 1 comprises a bobbin holder 5 receiving a supply bobbin 7. The supply bobbin 7 comprises a bobbin core 9 and the continuous material 3 wound on the bobbin core 9. In the state shown in figure 1 , the supply bobbin 7 is essentially exhausted and less than a full turn of the continuous material 3 remains on the bobbin core 9. The bobbin holder 5 comprises a drive 11 for rotating the supply bobbin 7 about a rotation axis 13 to unwind the continuous material 3. The system 1 comprises a controller 15 controlling the drive 11.

The continuous material 3 unwound from the supply bobbin 7 is conveyed to a processing location 17. In the illustrated embodiment, the continuous material 3 is a web of reconstituted tobacco material. Further, in the illustrated embodiment, a crimping station 19 is provided at the processing location 17. The crimping station 19 comprises crimping rollers 21 for crimping the continuous material 3. The crimping rollers 21 create creases or weakened portions in the continuous material 3 to facilitate further processing of the continuous material 3.

Between the bobbin holder 5 and the processing location 17, the continuous material 3 runs through a splicing station 23. The splicing station 23 is configured to splice the continuous material 3 from the supply bobbin 7 with continuous material 25 from a replacement supply bobbin 27, once the supply bobbin 7 is exhausted. The splicing station 23 comprises a first tool 29 in the form of a lower tool and a second tool 31 in the form of an upper tool. The continuous material 3 from the supply bobbin 7 runs in between the first tool 29 and the second tool 31 on its way from the supply bobbin 7 to the processing location 17. The system 1 comprises a positioning mechanism 33, such as a robot arm. The positioning mechanism 33 positions the continuous material 25 from the replacement supply bobbin 27 in between the first tool 29 and the second tool 31 as well. Alternatively, the continuous material 25 from the replacement supply bobbin 27 may be manually positioned in between the first tool 29 and the second tool 31 , for example. For splicing, the first tool 29 and second tool 31 are moved towards each other to combine the continuous material 3 from the supply bobbin 7 with the continuous material 25 from the replacement supply bobbin 27. The splicing station 23 may comprise a wetting unit 35 wetting one or both of the continuous material 3 from the supply bobbin 7 and the continuous material 25 from the replacement supply bobbin 27 to increase their tendency to stick to each other.

The system 1 comprises a bobbin exhaustion sensor 37 to detect exhaustion of the supply bobbin 7. Figure 2 shows the bobbin exhaustion sensor 37 and the supply bobbin 7 as received in the bobbin holder 5. The bobbin exhaustion sensor 37 monitors a monitoring region 39 through which a circumferential surface of the supply bobbin 7 passes, when the supply bobbin 7 is rotated about the rotation axis 13. The bobbin exhaustion sensor 37 determines whether a portion of the circumferential surface of the supply bobbin 7 located in the monitoring region 39 is formed by the continuous material 3 or by the bobbin core 9.

During most of the unwinding, the portion of the circumferential surface of the supply bobbin 7 located in the monitoring region 39 is formed by the continuous material 3 wound on the bobbin core 9. Only when less than a full turn of the continuous material 3 remains on the bobbin core 9, the circumferential surface of the bobbin core 9 that was previously covered by the continuous material 3 becomes visible. Figure 2 shows the situation where less than a full turn of the continuous material 3 remains on the bobbin core 9 and a border 41 between a portion of the circumferential surface of the bobbin core 9 that is covered by the continuous material 3 and a portion of the circumferential surface of the bobbin core 9 that is not covered by the continuous material 3 is located in the monitoring region 39. At this point, the bobbin exhaustion sensor 37 detects a difference between the surface of the continuous material 3 and the surface of the bobbin core 9. When the border 41 moves through the monitoring region 39, the bobbin exhaustion sensor 37 detects that the portion of the circumferential surface of the supply bobbin 7 located in the monitoring region 39 ceases to be formed by the continuous material 3 and starts to be formed by the bobbin core 9. This may be detected by the bobbin exhaustion sensor 37 based on a color measurement, for example. In particular, the bobbin exhaustion sensor 37 may be configured to detect a difference between a color of the continuous material 3 and a color of a circumferential surface of the bobbin core 9.

Detection by the bobbin exhaustion sensor 37 that the portion of the circumferential surface of the supply bobbin 7 located in the monitoring region 39 is no longer formed by the continuous material 3, but by the bobbin core 9, may be considered as an indication that the supply bobbin 7 is exhausted. The supply bobbin 7 may be considered as exhausted, when less than a full turn of the continuous material 3 remains on the bobbin core 9.

As shown in figure 1 , the system 1 comprises a counter structure 43 in the form of a counter roll. The counter structure 43 is guided in a guide structure 45 for movement along an axial direction towards the rotation axis 13 or away from the rotation axis 13. In the support structure 45, the counter structure 43 is biased towards moving radially inwards towards the rotation axis 13. During unwinding of the continuous material 3, the counter structure 43 is and remains in contact with the continuous material 3. The counter structure 43 moves in the guide structure 45 to follow a decreasing diameter of the supply bobbin 7 during the unwinding. The counter structure 43 defines a position where the continuous material 3 disengages from the supply bobbin 7 during unwinding.

The system 1 comprises a thickness sensor 47 determining a thickness of the supply bobbin 7. The thickness of the supply bobbin 7 decreases during unwinding of the continuous material 3.

As indicated in full lines in figure 1 , the thickness sensor 47 may be a distance sensor measuring a distance between itself and the circumferential surface of the supply bobbin 7. The thickness of the supply bobbin 7 is an indication of how much continuous material 3 remains on the bobbin core 9.

In an alternative indicated in dashed lines in figure 1 , the thickness sensor 47 may determine the thickness of the supply bobbin 7 based on a position of the counter structure 43. In particular, the thickness sensor 47 may measure or determine a position of the counter structure 43 with respect to the movement of the counter structure 43 along the radial direction as guided by the guide structure 45.

Measurement results from the bobbin exhaustion sensor 37 and the thickness sensor 47 are provided to the controller 15. The controller 15 controls the drive 11 based on measurement results from the bobbin exhaustion sensor 37 and the thickness sensor 47.

In particular, the controller 15 may control the drive 11 according to the diagram shown in figure 3. The horizontal axis 49 in figure 3 is a time axis and the vertical axis 51 in figure 3 indicates an unwinding speed. In a first phase of unwinding, the controller 15 controls the drive 11 to unwind the continuous material 3 with an operating unwinding speed 53. Once the measurement by the thickness sensor 47 indicates that a thickness of the supply bobbin 7 is below a predetermined threshold thickness, the controller 15 controls the drive 11 to reduce the unwinding speed to an intermediate unwinding speed 55 below the operating unwinding speed 53, but above zero. When, at a later stage, the bobbin exhaustion sensor 37 indicates that the supply bobbin 7 is exhausted, that is that less than a full turn of the continuous material 3 remains on the bobbin core 9, the controller 15 controls the drive 11 to stop unwinding. Thus, the unwinding speed is reduced from the intermediate unwinding speed 55 to zero.

Reducing the unwinding speed to zero happens sufficiently fast that there is still contact between the circumferential surface of the bobbin core 9 and the continuous material 3, when the unwinding speed reaches zero.

According to an alternative, the controller 15 controls the drive 11 to unwind the continuous material 3 with the operating unwinding speed 53 until the bobbin exhaustion sensor 37 indicates that the supply bobbin 7 is exhausted, and then controls the drive 11 to stop unwinding, without the intermediate phase of controlling the drive 11 to reduce the unwinding speed to an intermediate unwinding speed 55 below the operating unwinding speed 53 in response to a thickness of the supply bobbin 7 being below a predetermined threshold thickness.

Figure 4 shows a sequence of operational states during unwinding, wherein unwinding proceeds from the state indicated in the left part of figure 4 to the state indicated in the right part of figure 4. In the left part of figure 4, the thickness of the supply bobbin 7 is still above the threshold thickness and unwinding continues at the operating unwinding speed 53. In the middle part of figure 3, the thickness of the supply bobbin 7 has fallen below the threshold thickness and unwinding continues with the smaller intermediate unwinding speed 55. In the right part of figure 4, unwinding has stopped based on a signal from the bobbin exhaustion sensor 37. Since there is still some of the continuous material 3, although less than a full turn of the continuous material 3, on the bobbin core 9 after the unwinding speed has been reduced to zero, the counter structure 43 may still clamp the continuous material 3 against the bobbin core 9 so that tension of the continuous material 3 downstream of the supply bobbin 7 is maintained.

The controller 15 may initiate splicing by the splicing station 23 after the unwinding speed has been reduced to zero.

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

Claims

1 . System for supplying a continuous material for aerosol-generating articles, comprising: a bobbin holder configured to receive a supply bobbin comprising a bobbin core and a continuous material wound around the bobbin core, such that the supply bobbin is rotatable about a rotation axis for unwinding the continuous material; and a bobbin exhaustion sensor configured to monitor a monitoring region through which a circumferential surface of the supply bobbin passes, when the supply bobbin is rotated about the rotation axis; wherein the bobbin exhaustion sensor is configured to determine whether a portion of the circumferential surface of the supply bobbin located in the monitoring region is formed by the continuous material or by the bobbin core.

2. System according to claim 1 , wherein the bobbin exhaustion sensor is configured to carry out an optical measurement of the portion of the circumferential surface of the supply bobbin located in the monitoring region.

3. System according to claim 2, wherein the optical measurement is a color measurement.

4. System according to any one of the preceding claims, wherein the system is configured to slow or stop unwinding the continuous material in response to the bobbin exhaustion sensor detecting that the portion of the circumferential surface of the supply bobbin located in the monitoring area is formed by the bobbin core.

5. System according to any one of the preceding claims, further comprising a splicing unit configured to splice the continuous material with continuous material from a replacement supply bobbin, wherein the system initiates splicing in response to the bobbin exhaustion sensor detecting that the portion of the circumferential surface of the supply bobbin located in the monitoring area is formed by the bobbin core.

6. System according to any one of the preceding claims, further comprising a counter structure configured to press the continuous material towards the bobbin core.

7. System according to any one of the preceding claims, further comprising a thickness sensor configured to determine a thickness of the supply bobbin, in particular based on a position of the counter structure.

8. System according to claim 7, wherein the system is configured to slow unwinding the continuous material in response to the thickness of the supply bobbin measured by the thickness sensor being below a predetermined threshold thickness.

9. Method of supplying a continuous material for aerosol-generating articles to a processing location, the method comprising:

- conveying the unwound continuous material to a processing location; and

- detecting exhaustion of the supply bobbin by detecting a difference between a surface of the continuous material and a circumferential surface of the bobbin core.

10. Method according to claim 9, wherein the detecting the difference between the surface of the continuous material and the circumferential surface of the bobbin core comprises detecting a color difference between the surface of the continuous material and the circumferential surface of the bobbin core.

11. Method according to claim 9 or 10, further comprising slowing or stopping one or both of unwinding the continuous material and conveying the unwound continuous material in response to detecting that the supply bobbin is exhausted.

12. Method according to any one of claims 9 to 11, further comprising initiating splicing of the continuous material with continuous material from a replacement supply bobbin in response to detecting that the supply bobbin is exhausted.

13. Method according to any one of claims 9 to 12, further comprising reducing a rotational speed of the supply bobbin during the unwinding in response to determining that a thickness of the supply bobbin has fallen below a predetermined threshold thickness.

14. Use of a color measurement device for determining whether a supply bobbin is exhausted during unwinding a continuous material from the supply bobbin, wherein the color measurement device determines whether a portion of a circumferential surface of the supply bobbin located in a monitoring region through which the circumferential surface of the supply bobbin passes during the unwinding is formed by the continuous material or by a bobbin core of the supply bobbin.

15. System, method or use according to any one of the preceding claims, wherein the continuous material comprises an aerosol-generating material.