Device and method for inspecting a front surface of a rod-shaped smoking article

Abstract

The present invention relates to a device (10) for inspecting an end face (51) of a rod-shaped smoking article (5), wherein the smoking articles (5) can be fed onto a guide device (4) in a longitudinally axial arrangement and can be conveyed transversely axially from the longitudinally axial guide device (4) via a transverse conveyor (2), comprising a camera (20) which is configured to capture images of the end face (51) located in a capture position (III), and an electronic signal processing device (24) for evaluating the images captured by the camera (20). A position sensor (13) directed towards a measurement position (II) is provided, which generates a signal when the smoking articles (5) are conveyed through the measurement position (II) and transmits it to the camera (20), and the camera (20) can be triggered and / or moved into a trigger position depending on the signal from the position sensor (13).

Description

[0001] The present invention relates to devices for inspecting an end face of a rod-shaped smoking article with the features of the preambles of claims 1 and 2 and methods for inspecting an end face of a rod-shaped smoking article with the features of the preambles of claims 11 and 12.

[0002] Stick-shaped smoking products include, for example, cigarettes, cigarillos, heat-not-burn (HNB) products, or similar products intended for inhalation. Despite the term, these products may contain not only smoke but also, or alternatively, essential oils or medicinal substances intended for inhalation. The term "stick-shaped smoking products" also encompasses precursors such as filter sticks, tobacco sticks with tobacco material stabilized by a wrapping strip, segments of HNB products like tubular cooling sections, flavor-enhancing segments, or the like, which are subsequently combined with other precursors to form a finished stick-shaped smoking product.

[0003] For the sake of simplicity, the rod-shaped smoking articles and precursors of smoking articles are referred to as products in the following description.

[0004] A conveying system is used to transport products. This system includes a format section in which an endless strand of material, such as tobacco or tow, is placed onto an endless web of wrapping material. The wrapping material's edges are then folded over and glued to form a rigid strand. This rigid strand is subsequently cut into cylindrical or rod-shaped products of a predetermined length by a rotating cutter carrier with several radially outward-projecting blades. After cutting, the products are advanced along a guide system as a strand of adjacent individual products in a longitudinal axial transport direction to a receiving point, or alternatively, they can be actively conveyed further.At the receiving point, the products are conveyed from the guide unit by a longitudinal conveyor and transported to a transfer point, where they are transferred from the longitudinal conveyor to a transverse conveyor, perpendicular to their longitudinal direction. The rigid strand or the strand of adjacent individual products can also be present without wrapping paper, for example, for conveying and using non-wrapped acetate filters (NWA filters).

[0005] The longitudinal conveyor consists of a rotary drum with a plurality of projecting, rotatably mounted lever arms. Each lever arm has one or more axially spaced receptacles, each equipped with one or more channels or troughs that are aligned parallel to the products being fed and can be pressurized with negative pressure. During the drum's rotation, the lever arms appear to rotate in the opposite direction to the drum's rotation, causing the receptacles to follow an elliptical path. The receptacles themselves are held in a constant, preferably horizontal, orientation by a mechanism during the rotation of the drum and lever arms. This ensures that the products held in the receptacles are aligned, with their longitudinal axes preferably always parallel to the conveying direction of the incoming strand.As the drum rotates, the receivers with their integrated troughs are guided so close to the products at a transfer point that the products are drawn in by the negative pressure acting in the troughs and conveyed away by the conveyor. During the subsequent transport movement, the products are moved to a transfer point where the troughs, with the products held within them, preferably move transversely to their longitudinal axes or to the transport direction of the guide device. Furthermore, a transverse conveyor is provided, which is also formed by a rotatably driven drum, but whose axis of rotation is preferably arranged at a right angle to the axis of rotation of the longitudinal conveyor.On the radially outer surface of the transverse conveyor, a plurality of channels, which can also be pressurized and are aligned parallel to the axis of rotation of the transverse conveyor, are provided, which are guided so close to the channels of the longitudinal conveyor and the products held therein at the transfer point that the products are taken over transversely to their longitudinal axis and transported further.

[0006] One problem with transporting the products is that the troughs of the longitudinal conveyor's receiving unit must move at a higher speed than the speed of the products being fed (also called overspeed) at the transfer point. This prevents the products being fed onto the longitudinal conveyor on the guide device from accumulating or colliding with the following product during the transfer movement. The overspeed also depends on the length of the products, since the rotational speed of the longitudinal conveyor remains the same regardless of the product's length, and the feed rate must be adjusted to a predetermined number of products being transferred per unit of time.For these reasons, under unfavorable conditions, the products are transferred at up to twice the feed rate. Furthermore, the troughs themselves have a certain surface roughness, which influences the frictional forces acting between the troughs and the products during transfer.

[0007] Due to this overspeed, the products are accelerated abruptly during transfer, which exerts specific axial and radial forces on them. These forces are one of the causes of product head breakage. Therefore, the overspeed should generally be as low as possible or only slightly higher than the product feed speed. Furthermore, it is unavoidable that the bars will slip during transfer, which can be caused, for example, by excessive overspeed or a reduction in the surface roughness of the channels after prolonged operation. This slip can result in a deviation of the actual position of the products along the longitudinal channel of the longitudinal conveyor from the specified target position, which in turn inevitably leads to a deviation of the actual position of the products along the longitudinal channel of the transverse conveyor from the specified target position.Since the products are transported by the transverse conveyor exclusively perpendicular to their longitudinal axes, this deviation persists throughout the transport route unless it is corrected, for example, by a lateral support disc. The orientation of the products in the troughs of the transverse conveyor is particularly important when the products are transported at double length and are cut into single-length products in this position on the transverse conveyor, as the position of the products in the troughs of the transverse conveyor, with a fixed cutting edge, significantly influences the subsequent lengths of the cut, single-length products.

[0008] For quality control during product manufacturing, for example in filter / cigarette production, filter manufacturing machines are equipped with an end-surface sensor based on imaging technology. The products typically undergo optical inspection using a camera designed to capture images of the product's end surface. The images captured by the camera are then evaluated by an electronic signal processing unit.

[0009] A measuring device for online measurement is known, for example, from EP 2 677 273 B1. The measuring device is designed for the optical inspection of the end faces of products conveyed in a transverse conveyor and, in one embodiment, proposes quality inspection using a digital camera for 2D recordings. US 2015 / 0374028 A discloses a device for inspecting the porosity of a rod-shaped smoking article.

[0010] However, the deviation of the actual position from the target position of the products in the cross conveyor of up to ± 5 mm implies a blurring of the recorded images due to the positioning of the products within the troughs of the cross conveyor that deviates from the focal plane of the camera and is inaccurate, which makes a reliable inspection of the end face on the drum difficult.

[0011] The products typically align axially within the drum's recesses towards the center of the discharge drum. This means that the distance between the end face of a product and the camera changes when the product length or format changes. Consequently, after the length or format change, the distance between the camera and the end face being inspected is different than before, and a valid measurement with the camera is not possible. According to current technology, the camera must be readjusted after every format change.

[0012] Inaccurate adjustment leads to a blurred image. Furthermore, the image scale must be maintained to ensure correct image processing in the electronic signal processing unit. Therefore, an error in the camera's adjustment, or in the distance between the camera and the end face being inspected, represents a source of error that is difficult or impossible to detect using the measurement data. Consequently, there is a risk that the camera's measurements will be inaccurate, but this will go unnoticed. The deviation described above between the actual and target positions of the products in the cross conveyor represents an additional deviation that cannot be corrected by adjustment. This can lead to products of reduced quality not being properly identified.

[0013] One object of the invention is to provide a device and a corresponding method which enable effective and reliable quality assurance through reliable optical inspection of the products.

[0014] To solve the problem, the invention proposes devices with the features of claims 1 and 2, and methods with the features of claims 11 and 12. Further preferred developments of the invention can be found in the dependent claims, the figures, and the accompanying description.

[0015] According to the invention, it is proposed that a position sensor directed towards a measuring position is provided, which generates a signal when the smoking articles are conveyed through the measuring position and forwards it to the camera, and the camera can be triggered and / or moved into a trigger position depending on the signal of the position sensor.

[0016] The invention recognizes that the distance between the camera and the smoking device must maintain a specific value in order to generate a sufficiently sharp image for evaluation. Triggering the camera based on the position sensor signal ensures that the camera only captures images when the smoking device is in a defined position that corresponds to the measurement position at the time of sensing by the position sensor. The signal indicating that the smoking device is in the measurement position is then transmitted to the camera to trigger a recording and / or create a favorable condition for recording, enabling a sharp image. Sensing can be implemented in various ways, for example, by referencing the smoking device directly and / or a machine component linked to the smoking device's position.The defined position of the smoking device allows the camera to be positioned and / or moved into the trigger position such that the distance between the camera and the smoking device corresponds to the specified distance, enabling a sharp image to be captured. Moving the camera into the trigger position ensures precise distance adjustment and a sharp image of the front surface. Fluctuations in the position of the smoking device, for example during handling, can thus be compensated for when taking the image. Variations in the length of the smoking device can also be compensated for without additional effort. A manual adjustment of the trigger position to the corresponding length of the smoking device, which is otherwise common in the prior art, is therefore unnecessary; that is, the device and the corresponding method according to the invention operate independently of the format.The camera can capture an image by ensuring exposure for a specific duration, for example, fractions of a second, based on the generated signal. During this exposure, a light source illuminates the surface to be inspected. Optionally, the light source can be an LED. The illumination duration is preferably shorter than the exposure time.

[0017] Preferably, the camera simultaneously triggers an image capture of the smoking item detected by the position sensor upon receiving the signal. This ensures that, when the distance between the camera and the smoking item corresponds to a value defined for a sharp image, a sharp image of the smoking item as it passes the position sensor can be recorded. In this embodiment, the smoking item passes the focal plane of the camera lens at the moment the signal is generated; that is, the measurement position lies within the camera's focal plane, or the trigger position is offset from the measurement position by a value corresponding to the focal plane. Simultaneous triggering of an image capture thus results in a sharp image of the sensed or detected smoking item.Simultaneous triggering also includes time differences caused by signal technology, which can result, for example, from the signal line from the position sensor to the camera or from the signal processing in the position sensor and / or the camera, and which can be in the range of a few microseconds.

[0018] According to the invention, the electronic signal processing device determines a trigger point for the camera to take an image, depending on the signal from the position sensor and the time required for the smoking item to move from the measuring position to the recording position. This allows, for example, the spatial decoupling of the position sensor and the camera by utilizing the movement of the smoking item and / or the conveying device. In this embodiment, the smoking item passes the focal plane with a time delay after the signal is generated, for example, due to the movement of the conveying device. Thus, the camera can be directed at a recording position different from the measuring position, which the smoking item passes at a defined time, enabling a camera arrangement that can be adapted to the specific design requirements.The trigger point is determined in such a way that the smoking item detected by the position sensor moves through the recording position at the exact time of triggering, in order to be able to take defined and product-related recordings.

[0019] Preferably, the trigger point is determined as a function of the movement of the transverse conveyor in order to utilize a defined angular velocity or rotational speed of the transverse conveyor, which is preferably designed as a drum, for an accurate prediction of the movement of the smoking products within the conveyor and thus to determine the movement of the smoking products by the camera's position. In this embodiment, the optical axis of the camera is preferably parallel to the axis of rotation of the transverse conveyor and therefore parallel to the longitudinal axes of the smoking products conveyed in the transverse conveyor.

[0020] Advantageously, the trigger point is determined based on the movement of the smoking product in a specific transport direction. Within the guide, the transport direction of the smoking product is the same as the longitudinal axis of the smoking product, which is conveyed as a continuous strand. Preferably, the trigger point is determined based on the transport direction of the smoking product within the guide, or parallel to it, as this utilizes the movement of the smoking product in or against the direction of the camera, which is the relevant direction for a sharp image of the end face. In the transverse conveyor, the transport direction of the smoking product is perpendicular to its longitudinal axes, and from the transport direction and the position of the smoking product, it is possible to precisely determine when the respective products pass the recording position.

[0021] Preferably, the position sensor is arranged such that it detects the position of a smoking item being transported by a longitudinal conveyor, which is located between the guide device and the transverse conveyor and can be driven into a rotational movement. This allows the sensor to capture the smoking item after it has been transferred from the longitudinal conveyor to the guide device at a transfer point. The longitudinal conveyor conveys the smoking items in and / or parallel to the transport direction, or in the longitudinal axial direction of the smoking items. Thus, the movement of the longitudinal conveyor can preferably be used to determine the trigger point. In this embodiment, a product-related image of the smoking item detected by the position sensor is taken after it assumes an imprecise position in the grooves of the longitudinal conveyor holding the smoking item due to excessive speed.The source of error in the transfer of the smoking articles thus lies upstream of the measuring position with respect to the transport direction, so that this error is already included in the detected position of the smoking article and can be compensated for. In this embodiment, a quality check can be carried out at a defined position before the transfer to the transverse conveyor. For example, the transport speed of the longitudinal conveyor in the transport direction can be included in determining the trigger point.

[0022] Preferably, the trigger point is determined as a function of the rotational movement of the longitudinal conveyor. In this embodiment, the longitudinal conveyor is preferably designed as a drum and performs a rotational movement around an axis of rotation. Due to the rotation, preferably at a constant angular velocity, the smoking product is conveyed at a definable speed, and the position for recording at the recording point can be precisely determined from the measuring position.

[0023] Preferably, the trigger point is determined by taking into account a rotation angle of the longitudinal conveyor resulting from the measuring and recording positions, in order to make a defined position for quality inspection determinable in a particularly simple and precise manner based on the dynamics of the longitudinal conveyor. The rotation of the longitudinal conveyor by an angle results in a movement transverse to the transport direction or to the longitudinal axis of the smoking product and allows the camera to be positioned so that its optical axis does not have to be directed towards the guide track. The camera can be adapted to the design requirements and arranged with its optical axis parallel to the transport direction of the guide track.The trigger point is determined in such a way that, at the time the measurement signal is received by the position sensor, the time required to move the detected smoking article transported by the longitudinal conveyor from the measurement position to the recording position for the camera to capture the image is added.

[0024] Preferably, the position sensor is configured to generate the signal when passing the front surface to be inspected, in order to couple the signal directly to the position of the front surface to be inspected and to be able to take sharp pictures of it with the camera.

[0025] In an advantageous embodiment, the camera has a focal plane and can be triggered and / or moved such that the end face to be inspected is located in the focal plane or crosses the focal plane at a defined time to capture an image. Thus, the focal plane is a target plane in which the end face of the product should be located to obtain a sharp image of the end face. Using the position measured by the position sensor, the travel time until the end face crosses the focal plane can be calculated, and the image of the end face can be captured upon crossing the focal plane.

[0026] Advantageously, the camera can be moved in or against the direction of the end face by means of a shifting device, in order to adjust the distance between the camera and the end face, i.e., between the trigger position and the recording position. For example, the camera's shifting direction is aligned parallel to the axis of rotation of the transverse conveyor, to the direction of flow of the smoking products in the guide device, and / or perpendicular to the axis of rotation of the longitudinal conveyor.

[0027] Preferably, the camera is adjustable to a focal plane to capture a sharp image. In this embodiment, the camera preferably has a zoom lens and / or autofocus. In this embodiment, the camera has a variable focal plane, and the focal plane can be adjusted to the determined position of the smoking product in the recording position by adjusting the camera.

[0028] The position sensor is advantageously an optical displacement sensor, in order to determine the distance between the position sensor and the smoking product.

[0029] Preferably, the position sensor comprises a light barrier, and the position sensor is preferably configured to detect a light beam perpendicular to the longitudinal axes of the smoking articles in order to effectively and easily detect the passage of the smoking article or the end face. In this embodiment, the signal is generated upon detection of a smoking article by the smoking article passing through the light barrier, thereby interrupting the light beam. This means that, for a brief moment—i.e., while the smoking article passes through the measuring position—the light beam does not reach the position sensor, thus triggering the signal. Preferably, the light beam is emitted by the position sensor and / or a light transmitter, and the position sensor is preferably designed as a light sensor configured to detect the light beam.

[0030] The invention is explained below with reference to preferred embodiments and the accompanying figures. Fig. 1 is a schematic illustration of a transverse conveyor with products contained therein; Fig. 2 is a schematic illustration of a device according to an embodiment of the invention, in which the camera can be triggered depending on a signal from the position sensor; Fig. 3 is a schematic illustration of a device according to a further embodiment of the invention, in which the camera can be moved into a trigger position depending on a signal from the position sensor; and Fig. 4 is a schematic illustration of an arrangement for recording end faces of products of different lengths.

[0031] Figure 1Figure 1 shows a schematic diagram of a transverse conveyor 2 containing smoking articles 5, which are hereinafter referred to as products 50, and the end faces 51 of the products 50 to be inspected, to illustrate the underlying problem. The transfer position of the products 50 onto the transverse conveyor 2 depends on various factors, such as the speed of the products 50 in a longitudinal conveyor 1 shown schematically. Typically, fluctuations in the positions of the products 50 occur in the Figure 3 The recesses 103 shown, which support the products 50, vary by up to approximately ± 5 mm in the longitudinal direction of the products 50. According to the prior art, this variation causes a blurred image of the end face 51 due to a Figure 1 Camera not shown 20.

[0032] In Figure 2Figure 10 shows a schematic diagram of a device 10 according to an embodiment of the invention, in which a camera 20 is provided that can be triggered depending on a signal from a position sensor 13. A signal processing unit 24 evaluates the images captured by the camera 20.

[0033] The products 50 are advanced on a guide device 4 as a strand of adjacent individual bars in a longitudinal axial transport direction I or strand direction to a transfer point, or alternatively, are actively transported further. The transport direction I is preferably defined by the guide device 4. At the transfer point, the products 50 are conveyed from the guide device 4 by a longitudinal conveyor 1, designed as a drum and shown only schematically in the form of ellipses, which is also referred to as a spider in the applicant's process. The products 50 are held in the longitudinal conveyor 1 in receptacles (not shown), for example, arranged on lever arms, and the longitudinal conveyor performs a rotational movement about an axis of rotation oriented perpendicular to the transport direction I.The receivers preferably maintain a constant, preferably horizontal, orientation during the rotation of the longitudinal conveyor 1, which ensures a constant, preferably horizontal, orientation of the products 50 during conveyance in the longitudinal conveyor 1. The lever arms move such that the products 50 describe an elliptical path during conveyance through the longitudinal conveyor 1. The products 50 are always preferably aligned parallel to the transport direction I in the guide device 4 and in the receivers of the longitudinal conveyor 1. The rotational movement of the longitudinal conveyor 1 causes the products 50 to be transported perpendicular or transverse to the feed direction I; the longitudinal axis of the products is always aligned in the transport direction I.However, this lateral movement can be neglected by a suitable arrangement of camera 20, a correspondingly large image area and / or a shift of a region of interest (ROI) defined in the image.

[0034] The product 50 moves, as in Figure 2 As shown, the product 50 passes through a measuring position II due to movement in the guide device 4, with the position sensor 13 being configured to detect the product 50 in measuring position II. In embodiments not shown, measuring position II can also be selected such that the product 50 passes through measuring position II due to the movement of the longitudinal conveyor 1. In this case, for example, the actual position of the end face 51 after transfer onto the longitudinal conveyor 1 is detected by means of a light barrier of the position sensor 13.

[0035] When product 50 passes measuring position II, the position sensor 13 generates the signal and transmits it to the signal processing unit 24. In the illustrated embodiment, the position sensor 13 is a light barrier configured to emit or detect a light beam perpendicular to the transport direction I. Product 50, fed by the conveyor 4 in transport direction 1, first passes the light beam of the position sensor 13 with an end face 51 to be inspected. This allows for an exact estimation of the further trajectory of the end face 51 on the conveyor 4 or on the elliptical path of the longitudinal conveyor 1.

[0036] The signal processing unit 24 is configured to determine a trigger time for the camera 20. The trigger time characterizes the image capture and can include times for the start and end of the exposure, as well as a time for illumination or times for the start and end of illumination by a lighting device (not shown). The illumination can preferably occur during the exposure, and in a preferred embodiment, the emission of a flash of light can be provided for illumination. The trigger time can, for example, result from the speed of the products 50 on the guideway and / or the angular velocity of the longitudinal conveyor 1. The trigger time is preferably determined such that the product 50 is moved from measuring position II to a recording position III between the time of measurement and the trigger time.At the determined trigger time, the product 50 reaches the recording position, and the camera 20 triggers the recording of an image of the product 50 detected by the position sensor 13, thus enabling a sharp, product-related image of the front surface 51 to be taken. The recording position III is preferably located in the focal plane of the camera 20 at a suitable distance from the camera 20.

[0037] In other embodiments, measuring position II and recording position III coincide. In these embodiments, the camera 20 simultaneously triggers a product-related image upon receiving the signal from the positioning device 13 in order to obtain a sharp image. The image of the product 50 is taken in such a way that its position is determined by the position sensor 13 when the image is triggered.

[0038] Between measuring position II and the recording position III, which characterizes the camera 20, the longitudinal conveyor 1 sweeps an angle α due to its rotational movement. During the movement between measuring position II and recording position III, or rather when sweeping over the angle α, the product 50 remains aligned parallel to the transport direction I and simultaneously undergoes a movement perpendicular to the transport direction I resulting from the rotational movement of the longitudinal conveyor 1. In this embodiment, measuring position II is located upstream of recording position III in the transport direction I. This means that, due to the product 50's movement in the transport direction I, it approaches recording position III after passing measuring position II, and the camera 20 triggers the image capture when the product 50 passes recording position III.Thus, the correct recording position III for the camera 20 results from the signal emitted by the position sensor 13 and the angle difference a.

[0039] Thus, the movement of the products 50 in the direction of the conveyor or transport direction 1 is used to obtain a recording of the end face 51 with the correct distance between camera 20 and end face 51. This can preferably be done after the products 50 have been picked up by the longitudinal conveyor 1.

[0040] Figure 3Figure 10 shows a device 10 according to a further embodiment of the invention, in which a camera 20 can be moved into a trigger position in or against the direction of the end face 51 of the products 50 depending on a signal from a position sensor 13, wherein the position sensor 13 is directed towards a measuring position II. The camera 20 is arranged here with an electronic signal processing unit 24 in a housing 104. The products 50 to be inspected are conveyed in a transverse conveyor 2 designed as a drum. The products 50 are held in troughs 103. The transverse conveyor 2 performs a rotational movement about a rotary axis at a defined angular velocity.

[0041] The position sensor 13 detects the position of the product 50 within the trough 103. The product 50 then moves in the direction of rotation according to the rotational movement and travels from the measuring position II to a recording position III, which is defined by the camera 20 and, in this embodiment, a beam deflection device 102. In other embodiments, the beam deflection device 102 can be omitted if the optical axis of the camera 20 is aligned coaxially with the transverse conveyor and thus directed towards the product 50. The beam deflection device 102 comprises, for example, prisms and / or mirrors.

[0042] During the movement of product 50 from measuring position II to recording position III, a time defined by the arrangement of positions II and III and the angular velocity of the transverse conveyor 2 elapses, during which the camera 20 can be moved into the trigger position. The trigger position of the camera 20 can be determined by the distance between camera 20 and product 50, as measured by the position sensor 13 at measuring position II, or by the position of product 50 in the troughs 103 of the transverse conveyor 2.

[0043] The camera 20 is mounted on a linear slide 100 to allow for adjustment of the camera 20. A motor 101 moves the position of the camera 20 along the linear slide 100 parallel to the longitudinal axis of the products 50, in order to adjust the distance between the camera 20 and an end face 51 of the product 50 to be inspected. The motor 101 is, for example, an electrically driven motor, preferably a stepper motor and / or a linear motor. The position of the camera 20 can be determined by means of a suitable sensor and / or, preferably, by means of the stepper motor. Based on the known positions of the product 50 and the camera 20, the trigger position of the camera 20 necessary for a sharp image can be set, for example, after a brand and / or format change.

[0044] In other embodiments, the displacement device 100 and / or the motor 101 can be dispensed with if, for example, the camera 20 has a variable focus plane that allows the adjustment of the focus plane of the camera 20 or the lens of the camera 20 to the distance between the camera 20 and the front surface 51.

[0045] It is also conceivable that, for example, after a format change, an operator of the device 10 performs a coarse adjustment adapted to the format, and a fine adjustment is carried out using the means described in the embodiments. The operator can preferably be given feedback on the automatic adjustment.

[0046] Figure 4Figure 20 schematically illustrates an arrangement for capturing images of the end faces 51 of products 50 with different lengths 204, 205. The different lengths 204, 205 of the products 50 can result, for example, from a change in format. In particular, after a change in format, the distances 201, 202 between the camera 20 and the end face 51 of the product 50 to be inspected will differ. A longer product 50 results in a smaller distance 201, while a shorter product 50 results in a larger distance 202. The camera 20 can be moved to a trigger position according to the distances 201, 202 and / or have a variable focus plane. The variable focus plane can be set so that it is always adjusted according to the distance 201, 202 when an image is captured.For example, the variable focal plane can be achieved using a zoom lens in order to focus and sharply image the end faces 51 at the given distances 201, 202. However, the different distances 201, 202 arise not only from a change in format, but also from an inaccurate positioning of the products 50 in, for example, a transverse conveyor 2, which can be compensated for according to the embodiments of the invention.

Claims

1. Device (10) for inspecting an end face (51) of a rod-shaped smoking article (5), wherein the smoking articles (5) can be fed on a guide means (4) in a longitudinally axial arrangement and can be conveyed away transversely axially from the longitudinally axial guide means (4) via a transverse conveyor (2), comprising - a camera (20), which is adapted to record images of the end face (51) positioned in a recording position (III), and - an electronic signal processing device (24) for evaluating the images recorded by the camera (20), wherein - a position sensor (13) directed to a measuring position (II) is provided, which generates a signal when the smoke articles (5) are conveyed through the measuring position (II) and transmits it to the camera (20), and - the camera (20) can be triggered depending on the signal of the position sensor (13), characterized in that - the electronic signal processing device (24) determines a triggering point in time of the camera (20) for triggering an image depending on the signal of the position sensor (13) and the time period required for the smoking article (5) to move from the measuring position (II) to the recording position (III).

2. Device (10) for inspecting an end face (51) of a rod-shaped smoking article (5), wherein the smoking articles (5) can be fed on a guide means (4) in a longitudinally axial arrangement and can be conveyed away transversely axially from the longitudinally axial guide means (4) via a transverse conveyor (2), comprising - a camera (20), which is adapted to record images of the end face (51) positioned in a recording position (III), and - an electronic signal processing device (24) for evaluating the images recorded by the camera (20), characterized in that - a position sensor (13) directed to a measuring position (II) is provided, which generates a signal when the smoke articles (5) are conveyed through the measuring position (II) and transmits it to the camera (20), and - the camera (20) can be moved into a triggering position depending on the signal of the position sensor (13),3. Device according to claim 1 or 2, characterized in that - the camera (20) simultaneously to the input of the signal triggers a recording of an image of the smoke article (5) detected by the position sensor (13).

4. Device according to claim 2, characterized in that - the electronic signal processing device (24) determines a triggering point in time of the camera (20) for triggering an image depending on the signal of the position sensor (13) and the time period required for the smoking article (5) to move from the measuring position (II) to the recording position (III).

5. Device according to one of the previous claims, characterized in that - the triggering point in time is determined depending on the movement of the smoking article (5) in a transport direction (I) of the smoking article (5).

6. Device according to one of the previous claims, characterized in that - the position sensor (13) is arranged in such a way that it detects the position of a smoking article (5) which is transported by a longitudinal conveyor (1) arranged between the guide means (4) and the transverse conveyor (2) and which can be driven to a rotational movement.

7. Device according to claim 6, characterized in that - the triggering point in time is determined depending on the rotational movement of the longitudinal conveyor (1).

8. Device according to claim 7, characterized in that - the triggering point in time is determined taking into account the angle of rotation (α) of the longitudinal conveyor (1) resulting from the measuring position (II) and the recording position (III).

9. Device according to one of the previous claims, characterized in that - the position sensor (13) is adapted to generate the signal when passing the end face (51) to be inspected.

10. Device according to one of the previous claims, characterized in that - the camera (20) has a focal plane, and - the camera (20) can be triggered and / or moved in such a way that the end face (51) to be inspected is located in the focal plane or crosses the focal plane at a defined point in time in order to record an image.

11. Method for inspecting an end face (51) of a rod-shaped smoking article (5), wherein the smoking articles (5) can be fed on a guide means (4) in a longitudinally axial arrangement and can be conveyed away transversely axially from the longitudinally axial guide means (4) via a transverse conveyor (2), comprising - the recording of images of the end face (51) located in a recording position (III) with a camera (20), - the evaluation of the images recorded by the camera (20) with an electronic signal processing device (24), wherein - with a position sensor (13) directed to a measuring position (II), a signal is generated and transmitted to the camera (20) when the smoking articles (5) are conveyed through the measuring position (II), and - the camera (20) is triggered depending on the signal of the position sensor (13), characterized in that - depending on the signal of the position sensor (13) and the time period which the smoking article (5) requires to move from the measuring position (II) to the recording position (III), a triggering point in time of the camera (20) for triggering an image is determined.

12. Method for inspecting an end face (51) of a rod-shaped smoking article (5), wherein the smoking articles (5) can be fed on a guide means (4) in a longitudinally axial arrangement and can be conveyed away transversely axially from the longitudinally axial guide means (4) via a transverse conveyor (2), comprising - the recording of images of the end face (51) located in a recording position (III) with a camera (20), - the evaluation of the images recorded by the camera (20) with an electronic signal processing device (24), characterized in that - with a position sensor (13) directed to a measuring position (II), a signal is generated and transmitted to the camera (20) when the smoking articles (5) are conveyed through the measuring position (II), and - the camera (20) is moved into a triggering position depending on the signal of the position sensor (13).

13. Method according to claim 11 or 12, characterized in that - the camera (20) simultaneously to the input of the signal triggers a recording of an image of the smoking article (5) detected by the position sensor (13).

14. Method according to one of claims 12, characterized in that - depending on the signal of the position sensor (13) and the time period which the smoking article (5) requires to move from the measuring position (II) to the recording position (III), a triggering point in time of the camera (20) for triggering an image is determined.

15. Method according to one of claims 11 to 14, characterized in that - the triggering point in time is determined depending on the movement of the smoking article (5) in a transport direction (I).

16. Method according to one of claims 11 to 15, characterized in that - the triggering point in time is determined depending on a rotational movement of a longitudinal conveyor (1) which is arranged between the guide means (4) and the transverse conveyor (2) and which can be driven to the rotational movement.

17. Method according to claim 16, characterized in that - the triggering point in time is determined taking into account the angle of rotation (α) of the longitudinal conveyor (1) resulting from the measuring position (II) and the recording position (III).

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