Monitoring device, packaging machine with such a monitoring device and method to operate such a monitoring device

Prior art

A monitoring device for a packaging machine, in particular a form, fill and seal machine, is already known. Such monitoring devices comprise at least one sensor unit to monitor a film material transported by the packaging machine along a transportation direction. Documents JP 2010 - 235 159 A, WO 2018/147736 Al, US 2018/0016047 Al, US 2014/0274629 Al, EP 3 757 554 Al,

DE 11 2020 001 058 T5, DE 20 2013 105 243 U1 and EP 3 741 690 Al disclose such monitoring devices.

Disclosure of the invention

The invention is based on a monitoring device for a packaging machine, in particular a form, fill and seal machine, with at least one sensor unit to monitor a film material transported by the packaging machine along a transportation direction, wherein the sensor unit comprises at least one, in particular exactly one, imaging unit, in particular a line scan camera or an area scan camera, which is configured to capture at least two different features of the film material.

It is proposed that the monitoring device comprises at least one velocity sensor element to measure a transportation velocity of the film material through a measuring area of the sensor unit. The packaging machine is preferably built as a vertical form, film and seal machine or as a horizontal form, film and seal machine. The packaging machine is preferably configured to pack a product for packing with the film material. In particular the packaging is configured to form a container, in particular a bag, out of the film material for the product for packing and/or is configured to wrap the film material around the product for packing. Preferably, the film material is stored on a reel that is suspended at or within the packaging machine until processed by the packaging machine. Alternatively, the film material is stored as a stack of pre-cut sheets. In an unreeled state of the film material, the film material comprises preferentially a maximum longitudinal extension, a maximum transverse extension and a maximum material thickness, which are mutual perpendicular to each other. Preferably the maximum longitudinal extension is larger, in particular more than 10 times larger, than the maximum transverse extension. Preferably the maximum transverse extension is larger, in particular more than 10 times larger, than the maximum material thickness. The material thickness is preferably thinner than 5 mm, more preferably thinner than 2 mm, even more preferably thinner than 1 mm, optionally thinner than 0.5 mm. In some embodiments, the film material can have a material thickness of less than 0.1 mm. The material thickness is preferably thicker than 0.025 mm. The film material can be single layered or multi-layered. The film material and/or at least one layer of the film material can be made from paper, a plastic, for example polypropylene, polyester and/or polyethylene, a textile and/or a metal. In particular the film material is made from a compound material, in particular a laminate. Optionally, the film material is made from renewable raw material and/or is bio-degradable. The film material and/or at least one layer of the film material can be a solid, a web, a mesh, a netting or the like. The film material comprises preferably an outside surface and an inside surface, which are essentially parallel to the maximum longitudinal extension and to the maximum transverse extension of the film material. The expression “essentially parallel” should in particular be understood as an alignment of a direction with respect to a reference direction, in particular a plane, wherein the direction deviates from the reference direction by less than 8°, preferentially by less than 5° and even more preferentially by less than 2°.The inside surface is preferentially configured to face, in particular to be in direct contact with, the product for packing in a packed state of the product for packing with the film material. For example, the inside surface of the film material may be made from or coated with a food safe material. In a packed state of the product for packing, the outside surface is preferentially configured to face away from the product for packing and in particular towards an environment. The packaging machine comprises preferably a guiding unit to transport, in particular an unreeled part of, the film material towards and/or through at least one processing station of the packaging machine. The guiding unit comprises preferentially guiding elements, such as rollers, band conveyers or the like, to convey, to divert and/or to span the film material along a guiding path through the packaging machine. The packaging machine may for example comprise a printing station to imprint the film material, a labelling station to affix a label to the film material, a forming station to form a container out of the film material, a cutting station to cut off a piece of the film material that is big enough to pack one unit of the product for packing or the like. The guiding unit is configured to transport the film material with the maximum longitudinal extension of the film material being held essentially parallel to the transportation direction. In particular, the guiding elements comprise a supporting surface to support the film material. The supporting surface of the guiding elements shows a maximum width at least essentially perpendicular to the transportation direction. The guiding unit is preferably configured to keep the maximum traverse extension of the film material essentially parallel to the maximum width of the nearest guiding element, while transporting the film material. The expression “essentially perpendicular” should in particular be understood as an alignment of a direction with respect to a reference direction, wherein the direction and the reference direction, in particular when viewed in a projection plane, enclose an angle of 90° plus or minus an optional deviation, wherein the deviation is less than 8°, preferentially less than 5°, even more preferentially less than 2°.

The imaging unit is preferably configured to monitor the outside surface of the film material. Alternatively or additionally, the imaging unit is configured to monitor the inside surface of the film material, in particular if the film material is at least partly translucent or transparent. In particular the imaging unit is configured to monitor the film material, while the film material is being transported by the guiding unit. Preferably the imaging unit is arranged and orientated towards the guiding unit, in particular to monitor an unreeled part of the film material. Preferentially the imaging unit is arranged along the transportation direction behind at least one processing station of the packaging machine and preferably before the forming station of the packaging machine, to monitor the film material in an at least partly processed and in particular unfolded state. The imaging unit is preferably configured to a contactless monitoring of the film material. Preferably the imaging unit is a camera with a maximum sensitivity in the optical spectrum, the infrared spectrum and/or the ultraviolet spectrum. Preferably, the imaging unit comprises a one-dimensional or a two-dimensional array of imaging elements for a space- resolved monitoring of the film material and in particular to take a contiguous image of the film material. Preferably, the imaging unit has a resolution of at least 1 px/mm, more preferably of at least 5 px/mm, even more preferably of at least 10 px/mm. In particular, the imaging unit can be designed as an active-pixel sensor, as a charged-coupled device sensor, as a contact image sensor or the like. The entirety of the imaging elements of the imaging unit may be provided by a single sensor or several discrete sensors coupled together, such as to provide a composite image of the film material. Preferably, if the imaging unit comprises several discrete sensors coupled together, measuring areas of these sensors overlap by at least one pixel or are directly adjacent. Alternatively, the measuring areas are apart from each other by less than 15 %, preferably less than 10 %, in particular less than 5 %, of a width of the measuring areas perpendicular to the transportation direction Preferably, the sensor unit comprises a light emitting element to emit optical light, infrared light and/or ultraviolet light towards the film material. The light emitting element and the imaging unit is preferably arranged on the same side regarding the guiding path, in particular the film material, such that the imaging unit detects light from the light emitting element that was reflected at the film material. Alternatively, the light emitting element or an optional additional light emitting element and the imaging unit are disposed on different sides of the guiding path, in particular the film material, such that the imaging unit detects light that was transmitted by the film material. Alternatively, the imaging unit is designed as an ultrasound unit and/or a tomography unit, in particular an electrical impedance measuring unit and or a magnetic resonance imaging unit.

Preferentially, the imaging unit is configured to take at least one image of the film material that is evaluable regarding at least two different features of the film material, in particular two different type of features. Different features of the film comprise for example the maximum transverse extension, a positioning of the film material with respect to a guiding element of the guiding unit, a positioning of a label on the film material, a presence of a damage of the film material, the posi- tion of a film spot of the film material, a positioning and/or correctness of a printing of the film material, a bar code on the film material or the like. To capture two different features of the film material, the sensor unit can comprise a driving unit to traverse and/or rotate the imaging unit, the imaging unit can comprise a measuring area that is wide enough to cover at least two features of the film material and/or the imaging unit comprises different acquisition modes, such as a bright field mode, a dark field mode, a mode with or without different spectral filters or the like.

With a monitoring device according to the invention the sensor unit can be kept advantageously simple. An advantageously low number of imaging units, in particular merely one imaging unit, is necessary to capture advantageously many features of the film material. The sensor unit can advantageously be designed without several different dedicated sensor units for each single feature. Setting up the sensor unit during a film material changeover can be executed advantageously simple and intuitively.

Furthermore, it is proposed that a width of a, in particular the above-mentioned, measuring area of an, in particular the above-mentioned, imaging unit, in particular a measuring area of the above-mentioned or of a further line scanning camera or of the above-mentioned or of a further area scanning camera, of the senor unit is at least essentially as wide as a width of the film material and/or as a maximum transportation width of a guiding unit of the packaging machine in a direction transverse to the transportation direction. In an alternative embodiment the sensor unit comprises the imaging unit with the measuring area width comparable to the film material and/or the guiding unit independently from the imaging unit that is configured to take at least two different features. Preferably the monitoring device comprises in this alternative embodiment at least the sensor unit. The width of the film material is preferably synonymous to the above-mentioned maximum transverse extension of the film material. The maximum transportation width is preferably shorter or identical to the maximum width of the guiding elements of the guiding unit. The maximum transportation width is in particular an upper limit for the width of the film material in order for the film material to be processable by the packaging machine as intended. A dimensioning being “essentially as wide as” another dimensioning should be understood in that sense that the dimension- ing amounts to at least 33 %, preferably more than 66 %, even more preferably more than 90 %, of the other dimensioning. In particular, the width of the measuring area is larger than the width of the film material and optional larger than the maximum transportation width. The width of the measuring area is preferably a dimensioning that extents traverse, in particular perpendicular, to the transportation direction. In particular, the measuring area is disposed in a plane that contains the guiding path. The imaging unit can be orientated in such a way, that the measuring area is distant from any guiding element of the guiding unit or directly at the supporting surface of one of the guiding elements of the guiding unit. Preferably the imaging unit comprises a multitude of imaging elements that are arranged in a single line traverse, preferentially at least essentially perpendicular, to the transportation direction, wherein a multitude is preferably a number high enough to achieve the above-mentioned resolution along the whole width of the measuring area. In at least one embodiment the imaging unit comprises at least two or more lines next to each other, wherein each line comprises a multitude of imaging elements, to achieve the above-mentioned resolution in a direction at least essentially parallel to the transportation direction. With a monitoring device according to the invention an advantageously large portion of the film material can be monitored, in particular with a single sensor unit. In particular, the amount of dedicated sensor units to monitor special features of the film material can be kept advantageously low.

In addition, it is proposed that the monitoring device comprises at least one evaluation unit that is configured to evaluate an image taken by the imaging unit regarding at least two different features of the film material. The evaluation unit comprises preferably at least one data input port, at least one data processor and at least one data output port. Preferably the evaluation unit comprises a processor, in particular a central processing unit, a memory, an input interface, an output interface, further electronical components, an operating program, control routines and/or calculation routines. The input interface of the evaluation unit comprises preferentially at least one data input port that is connected to the imaging unit, in particular to receive images or raw data to compile an image from the imaging unit. Optionally the input interface comprises a user input, in particular to manipulate an image of the film material by an operator of the packaging machine. Preferably the output interface comprises at least one display to present an image of the film material to an operator of the packaging machine. Preferentially the output interface comprises at least one control signal output port to output a control signal based on an evaluation of an image of the film material to the packaging machine. The evaluation of an image of the film material is preferably executed by the processor, in particular with or without a supervision by an operator of the packaging machine. In particular, the processor is configured to analyse an image of the film material using image recognition methods known in the art. The processor can be configured to analyse the whole image or at least one region of interest within the image. The at least one region of interest is preferably set in advance, in particular by an operator of the packaging machine and/or a pattern recognition algorithm of the evaluation unit. The at least one region of interest can cover all pixels of the image depicting the film material, in particular to distinguish it from a background of the film material, a region of the film material or a single feature of the film material, such as a film spot, a bar code, a label or the like. Preferably, a model of the film material is stored in the memory of the evaluation unit, for the processor to compare with an image of the film material. The model preferably comprises all intended features of the film material, that are monitored by the monitoring unit. Optionally, the model comprises common and/or historic unwanted features of the film material, such as a damage to the film material, misalignment of the film material with respect to the guiding unit, a wrinkling of the film material or the like. The evaluation unit can be designed as an integrable module for a control system of the packaging machine, a local stand-alone device connected to the sensor unit or as a remote server capable of communicating with the sensor unit via a public or private data network. In particular, the output port and/or the input port can be a cable connection port, a wireless communication antenna or the like for communicating with the control system, the sensor unit and/or other external devices or an internal interface such as a bus-system, a hard wired connection, a, in particular low range, wireless communication antenna or the like for communicating with other parts of the control system and/or with the sensor unit. With a monitoring device according to the invention the monitoring device can be designed with an advantageously low amount of different sensor units.

The velocity sensor element is preferably designed separately from the imaging unit. The velocity sensor element is preferably a rotational encoder measuring a rotation velocity of one of the guiding elements. Alternatively, the velocity sensor element is a laser surface velocimeter. The velocity sensor element is preferably connected to the evaluation unit to transmit the transportation velocity to the evaluation unit. Alternatively or additionally, the evaluation unit is configured to calculate the transportation velocity from changes between different images received from the imaging unit and a known update velocity between the images. Alternatively or additionally, the monitoring device queries the transportation velocity from the control system of the packaging machine. With a monitoring device according to the invention the monitoring device can advantageously adapt its operation to the transportation velocity. In particular, an update interval of the imaging unit can be optimized with respect to achieved resolution along the transportation direction and data volume to be processed by the evaluation unit.

Moreover, a packaging machine, in particular a vertical form, fill and seal machine or a horizontal form, film and seal machine, is proposed that comprises a, in particular the above-mentioned, monitoring device according to the invention and at least one, in particular the above-mentioned, guiding unit to transport the film material along the transportation direction. The packaging machine comprises preferably a bearing to mount at least one reel of film material. Preferably, the packaging machine comprises a splicing station to splice the film material from a used-up reel of film material with the film material of a new reel of film material. Optionally, the packaging machine comprises the printing station to imprint the film material. The packaging machine comprises optionally the labelling station to affix a label to the film material. Optionally, the packaging machine comprises a punching station to punch at least one hole into the film material. Preferentially, the packaging machine comprises the forming station to form a container, in particular a bag, a tubular bag, a doy pack or the like, out of the film material, wherein the container can comprise a zipper or not. In order to form the container, the forming station can be configured to fold the film material and/or to seal two or more segments of the film material. The packaging machine comprises preferentially a cutting station to cut off a piece of the film material that is big enough to pack one unit of the product for packing. Preferentially, the packaging machine comprises a filling station to fill the container formed out of the film material with the product for packaging, in particular by means of a filling pipe. Preferentially, the packaging machine comprises a sealing station to seal the container formed out of the film material and filled with the product for packaging. Two or more of the above-mentioned processing stations of the packaging machine can be combined in a single processing station to perform at least two of the above- mentioned processing steps of the film material. The guiding unit is in particular configured to transport the film material between separately designed processing stations and/or through the processing stations. Preferably the packaging machine comprises a further transportation unit to transport the product for packing in a state packed with the film material away from the processing stations. Preferably, the packaging machine comprises the control system to synchronize an operation of the processing stations with a feed rate of the film material. With a packaging machine according to the invention an advantageously high amount of automation can be achieved. Further, setting up the sensor unit during a film material changeover can be executed advantageously simple and intuitively.

Also, the invention is based on a method for operating a monitoring device according to the invention, in particular the above-mentioned monitoring device. It is proposed that in at least one method step at least one image taken by the imaging unit is evaluated regarding a splice tape position of the film material. In at least one method step of the method the imaging unit captures preferentially at least one image of the film material, in particular of the outside surface of the film material. The image taken by the imaging unit is preferably sent by the imaging unit to the evaluation unit. Preferably, in at least one method step the velocity sensor element measures the transport velocity of the film material, in particular a rotational velocity of one of the guiding elements of the guiding unit. The evaluation unit evaluates preferentially in at least one method step of the method the image received from the imaging unit. In particular, the imaging unit analyses the image received from the imaging unit with regards to at least two different features of the film material. Preferably the evaluation calculates from the transportation velocity received from the velocity sensor element a spatial relationship between consecutively received images from the imaging unit. Optionally the evaluation unit displays the images received from the imaging unit and/or a result of the evaluation via the output interface. For example, the evaluation unit evaluates one of the features with regards to presence or absence of that feature, positioning of the feature, alignment or misalignment of that feature, correctness or faultiness of an information content of the feature, classification and/or recognition of that feature based on machine learning or the like. Preferably, the monitoring device puts out a control signal to operate at least one of the processing stations in dependence of the evaluation of the image of the film material. Optionally, the monitoring device puts out a visual, auditive and/or haptic notification to an operator of the packaging machine, in particular if the image of the film material does or does not conform to the model of the film material stored in the memory of the monitoring device. In particular, the splice tape splices two batches of the film material for the packaging machine to operate continuously with a virtual endless supply of film material. Preferably, the evaluation unit recognises the position of the splice tape along the transportation direction. Preferably, the evaluation unit sends an incoming splice command to the control system of the packaging machine, when the evaluation unit recognises the splice tape position. Optionally, the evaluation unit encodes within the incoming splice command, whether the last instance of the feature pattern is complete or interrupted by the splice tape. The incoming splice command causes the packaging machine in particular to cut-off and discard a transition zone between two batches of the film material, comprising the splice tape and optionally a piece of the film material with an incomplete instance of the feature pattern. Alternatively, the incoming splice command causes the packaging machine to process the film material with the splice tape and marking it, wherein a container comprising the splice tape is in particular sorted out later. Processing and marking comprises for example to skip cutting and forming one piece of the film material containing two instances of the feature pattern to a double container. Alternatively processing and marking comprises an additional imprint on the container formed of the instance with an unwanted feature, such as a splice tape. With a method according to the invention a necessary supervision of the packaging machine by an operator can be kept at an advantageously low rate. With a method according to the invention features of the film material can be detected advantageously robustly and reliably. In particular, a limited measuring area of a sensor dedicated to a specific feature can be avoided. In particular, the detection of the features can show an advantageously low dependence of a relative positioning of the film material and the imaging unit. In particular, the monitoring device can advantageously compensate a misalignment of the imaging unit and the film material. Furthermore, a repositioning of features on the film material does not need a repositioning of the image unit. Furthermore, it is proposed that in at least one method step of the method the imaging unit takes images as a continuous video stream. Preferably, the evaluation unit sets an update interval at which the imaging unit sends consecutive images. Preferentially, the evaluation unit sets the update interval of the imaging unit in dependence of the transport velocity of the film material. Especially in an embodiment with a one-dimensional array of imaging elements of the imaging unit, the evaluation unit sets the update interval preferably to a value, at which the above-mentioned resolution parallel to the transportation direction can be achieved. Preferably the imaging unit has a maximum scanning rate, i.e. the inverse of a minimum update interval, of more than 1 kHz, preferentially of more than 5 kHz, even more preferentially of more than 10 kHz. In an embodiment with a two-dimensional array of imaging elements of the imaging unit, the evaluation unit sets the update interval preferably to a value, such that consecutive images of the film material have an overlap of at least one pixel along the transportation direction. With a method according to the invention the film material can be scanned with an advantageously high resolution. In particular, the whole film material can be recorded and evaluated.

In addition, it is proposed, that in at least one method step of the method at least one image taken by the imaging unit is evaluated regarding a film spot of the film material. Preferably the film material comprises a feature pattern. The feature pattern is in particular a set of different types of features, that is repeating itself along the transportation direction. The feature pattern is preferentially stored in the memory as the model of the film material. Preferably within each instance of the feature pattern along the transportation direction an arrangement of the features belonging to the feature pattern is identical. A concrete embodiment of each feature belonging to the same type of feature of the film material can be identical between instances of the feature pattern, e.g. a product identification, a food labelling or the like, or vary between the instances of the feature pattern, e.g. a serial number, a date/time of packing or the like. Preferably the feature pattern comprises the film spot as a feature. The film spot may be a feature on its own, e.g. a small dot, strip or the like, or alternatively a distinct graphical feature of a preprint of the film material is used as the film spot, e.g. a course of a curve, a colour change or the like. Preferably the evaluation unit analyses the image to find the film spot. In particular, the evaluation unit sends a cut command signal to the packaging machine at a defined time after the evaluation unit recognises the film spot. The defined time depends, in particular, on the position of the film spot relative to an edge of the film material to be cut and the transportation velocity. The cut command signal is in particular intended to synchronize the transportation velocity of the film material and the operation of the cutting station. The cut command signal can cause the guiding unit to stop the film material and/or the cutting station to cut off a piece of the film material, in particular a piece containing exactly one instance of the feature pattern. In some embodiments the cutting station waits for the cut command signal to cut, while the guiding unit transports the film material continuously. In another embodiment the cutting station cuts the film material in fixed time-intervals, while the guiding unit transports the film material intermittently as instructed by the cut command signal. In yet another embodiment the cutting station and the guiding unit are both controlled by the cut command signal. Preferably, the evaluation unit uses the film spot as a reference to determine a correct positioning and/or alignment of other features of the according instance of the feature pattern. With a method according to the invention an even higher degree of automatization can be achieved.

It is further proposed, that in at least one method step of the method at least one image taken by the imaging unit is evaluated regarding a film edge location of the film material. Preferably the film edge limits the outer surface of the film material. Optionally, the sensor unit comprises a physical reference element, such as a scale or a mark that is fixed relative to the imaging unit and disposed on the other side of the guiding path, in particular the film material, with respect to the imaging unit. In particular, the evaluation unit evaluates an image taken by the imaging unit and comprising the film material and the physical reference. In particular, the evaluation unit determines a distance of the film material from the physical reference element in a direction traverse to the transportation direction within the image in order to determine the film edge location. Alternatively, a digital reference element is assigned to at least one pixel of the image of the film material, in particular chosen by an operator of the packaging machine via the input interface, to define a set value and/or a maximum permissible value for the film edge location. With a method according to the invention an advantageously large measuring area is available for edge detection. In particular, a positioning of the film material relative to the physical reference element can be tracked across an advanta- geously wide space. A risk for having to readjust the sensor unit to cover the physical reference element and the film material can be kept advantageously low. An absolute positioning of the film material within the packaging machine, in particular in subsequent processing stations, can be controlled advantageously well.

Furthermore, it is proposed, that in at least one method step of the method at least one, in particular the above-mentioned, image taken by the imaging unit is evaluated regarding a bar code of the film material. Preferably the imaging unit takes an image of the film material comprising the bar code. Preferably, the evaluation unit recognises and reads the bar code from the image taken by the imaging unit. The evaluation unit can be configured to read a linear bar code, e.g. universal product code (UPC), European Article Number (EAN), Japanese Article Number (JAN) or the like and/or a matrix barcode, e.g. Quick response code (QR code), Data Matrix, Aztec Code, Han Xin Barcode, Dot Code or the like. Preferably, the evaluation unit identifies the model of the film material, to which features other than the bar code are compared to, in dependence of the bar code or checks whether the bar code is correct in dependence of the model of the film material, in particular chosen by an operator of the packaging machine. With a method according to the invention a manual executed random sampling of the film material with a hand scanner can be kept advantageously low. In particular, the monitoring unit can be connected to a database to automatically retrieve a model for the film material present in the packaging machine. In particular, models for different film material can be designed advantageously in advance.

It is also proposed, that in at least one method step of the method at least one, in particular the above-mentioned, image taken by the imaging unit is evaluated regarding a printing of the film material. The film material can comprise an external preprint, which was done before the film material is transferred to the packaging machine, and/or an internal imprint, which is done by the printing station of the packaging machine, for example a packaging date. The evaluation unit can be configured to evaluate an image taken by the imaging unit regarding the external preprint and/or the internal imprint. For example, the evaluation unit checks a colour scheme, visual content, design, text alignment, textual content or the like of the external preprint and/or the internal imprint. When detecting a misprint of the film material, the evaluation unit can send a flaw command to the control sys- tern of the packaging machine and/or inform an operator of the packaging machine. Preferably, the evaluation unit sends the flaw command to the packaging machine, if the misprint is limited to, in particular a single, instance of the feature pattern, to cause the packaging machine to cut-off and discard that instance of the feature pattern or to process that instance and marking it, so that it can be sorted out later. Preferentially, the evaluation unit causes the packaging machine to stop and/or informs an operator of the packaging machine via the output interface about the misprint, if the misprint extends over several instances of the feature pattern. With a method according to the invention the risk for unnoticed misprints of the film material can be kept advantageously low.

Furthermore, it is proposed, that in at least one method step of the method at least one, in particular the above mentioned, image taken by the imaging unit is evaluated regarding a punch hole within the film material. Preferably, the evaluation unit evaluates an image taken by the imaging unit regarding one or more punch holes within the film material, in particular one or more punch holes made by the packaging machine, in particular the punching station of the packaging machine. For example, the evaluation unit checks, whether an amount of punch holes, a positioning of the punch hole is correct and/or if the punch hole has been freed cleanly from any excess waste material. When detecting an incorrect or insufficient executed punch hole within the film material, the evaluation unit can send the flaw command to the control system of the packaging machine and/or inform an operator of the packaging machine. Preferably, the evaluation unit sends the flaw command to the packaging machine, if the damage is limited to, in particular a single, instance of the feature pattern to cause the packaging machine to cut-off and discard that instance of the feature pattern or to process that instance and marking it, so that it can be sorted out later. Preferentially, the evaluation unit causes the packaging machine to stop and/or informs an operator of the packaging machine via the output interface about the incorrect and/or insufficiently executed punch holes, if the punch holes in several instances of the feature pattern are incorrect and/or insufficiently executed. With a method according to the invention a risk of misaligned punch holes can be kept advantageously low. In particular, an advantageously reliable mounting of different units of the product for packing by use of the punch hole of the respective container made from the film material can be achieved. In addition, it is proposed, that in at least one method step of the method at least one, in particular the above-mentioned, image taken by the imaging unit is evaluated regarding a label of the film material. Preferably, the evaluation unit evaluates an image taken by the imaging unit regarding one or more labels affixed to the film material, in particular one or more labels affixed by the packaging machine, in particular by the labelling station of the packaging machine. For example, the evaluation unit checks, whether an amount and/or positioning of the labels is correct, if the label is in accordance with the model of the film material and/or if the label sticks evenly to the film matrix or if there is a wrinkling of the label or a protruding part of the label. When detecting a faulty label of the film material, the evaluation unit can send the flaw command to the control system of the packaging machine and/or inform an operator of the packaging machine. Preferably, the evaluation unit sends the flaw command to the packaging machine, if the faulty label is limited to, in particular a single, instance of the feature pattern to cause the packaging machine to cut-off and discard that instance of the feature pattern or to process that instance and marking it, so that it can be sorted out later. Preferentially, the evaluation unit causes the packaging machine to stop and/or informs an operator of the packaging machine via the output interface about the faulty label, if several, in particular consecutive, instances of the feature pattern comprise faulty labels. With a method according to the invention labelling of the film material can be adapted on advantageously short-term, in particular without repositioning the senor unit.

It is further proposed, that in at least one method step of the method at least one, in particular the above-mentioned, image taken by the imaging unit is evaluated regarding a damage of the film material. Preferably, the evaluation unit evaluates an image taken by the imaging unit regarding a damage, in particular a tear, of the film material. For example, the evaluation unit searches an image of the film material taken by the imaging unit by means of edge recognition, an unintended colour variation, an uneven brightness across the film material or other abnormal features of the film material. When detecting a damage of the film material, the evaluation unit can send the flaw command to the control system of the packaging machine and/or inform an operator of the packaging machine. Preferably, the evaluation unit sends the flaw command to the packaging machine, if the damage is limited to, in particular a single, instance of the feature pattern to cause the packaging machine to cut-off and discard that instance of the feature pattern or to process the instance and marking it, so that it can be sorted out later. Preferentially, the evaluation unit causes the packaging machine to stop and/or informs an operator of the packaging machine via the output interface about the damage, if the damage extends over several instances of the feature pattern and/or if the damage includes the film edge. With a method according to the invention waste of the packaging machine can be kept advantageously low. In particular, a damage of the film material can be detected on an advantageously high portion of the film material, in particular on the whole film material.

The monitoring device according to the invention, the packaging machine according to the invention and/or the method according to the invention are/is herein not to be restricted to the application and implementation described above. In particular, for fulfilling a function herein described, the monitoring device according to the invention, the packaging machine according to the invention and/or the method according to the invention may comprise a number of individual elements, components, units and method steps, which differs from the number herein mentioned.

Drawings

Further advantages may be gathered from the following description of the drawings. In the drawings one exemplary embodiment of the invention is shown. The drawing, the description and the claims comprise a plurality of features in combination. The person skilled in the art will expediently also consider the features individually and will bring them together in further purposeful combinations.

The drawings show:

In Fig. 1 a schematic illustration of a packaging machine according to the invention comprising a monitoring device according to the invention, In Fig. 2 a schematic flow diagram of a method according to the invention and

In Fig. 3 a schematic illustration of a film material with several different exemplary features to be captured by an imaging unit of the monitoring device.

Description of the exemplary embodiment

Figure 1 shows a packaging machine 12, in particular a form, fill and seal machine. The packaging machine 12 comprises preferably one or more processing stations 78, 80 to process a film material 16. In particular, the packaging machine 12 comprises preferably at least one packing processing station 78 to pack a product for packaging with the film material 16. The packing processing station 78 is in particular configured to cut-off a piece of the film material 16, to form a container out of said piece or several pieces of the film material 16, to fill said container with a product for packaging and to seal that filled container, wherein the packaging machine 12 can be configured to execute the cutting off of the piece(s) of film material 16 before or after any of the other steps. Preferably, the packing machine comprises at least one pre-processing station 80 to modify the film material 16, in particular before processing the film material 16 with the packing processing station 78. In particular, the packaging machine 12 can comprise any, some or all of the following pre-processing stations 80: a splicing station to splice two batches of the film material 16, a labelling station to label the film material 16, a printing station to imprint the film material 16 and/or a punching station to punch a punch hole into the film material 16. The packaging machine 12 comprises at least one guiding unit 38 to transport the film material 16 along a transportation direction 18, in particular from one of the processing stations 78, 80 to another. For example, the guiding unit 38 comprises rollers to convey, divert and/or span the film material 16 along the transportation direction 18.

The packaging machine 12 comprises a monitoring device 10. The monitoring device 10 for the packaging machine 12 comprises at least one sensor unit 14 to monitor the film material 16 transported by the packaging machine 12 along the transportation direction 18. The sensor unit 14 comprises at least one, in particu- lar exactly one, imaging unit 20. The imaging unit 20 is for example, as shown here, a line scan camera. The imaging unit 20 is preferably arranged to monitor the film material 16 between the pre-processing station(s) 80 and the at least one packing processing station 78. Alternatively, the imaging unit 20 is arranged to monitor the film material 16 between two of the pre-processing stations 80. The imaging unit 20 is configured to capture at least two different features 22, 24, 26, 28, 30, 32, 34, 35 of the film material 16. For example, in Figure 1 the film material 16 shows a damage 60 as an unwanted feature 35 and a film edge location 48 as a feature 24 (cf. Fig. 3 for a more detailed view of an exemplary design of the film material 16 and some of the possible different features 22, 24, 26, 28, 30, 32, 34 of the film material 16 that are capturable by the imaging unit 20).

A width of a measuring area of the imaging unit 20, in particular the line scanning camera, of the senor unit 14 is at least essentially as wide as a width of the film material 16 and/or as a maximum transportation width 36 of the guiding unit 38 of the packaging machine 12 in a direction transverse to the transportation direction 18. Here the width of the film material 16 coincides with the maximum transportation width 36. Depending of a unit size of the product for packing the width of the film material 16 can also be smaller than the maximum transportation width 36. The maximum transportation width 36 is in particular defined by a maximum length of a supporting surface of the rollers perpendicular to the transportation direction 18, in particular reduced by a safety margin. Preferably, the width of the measuring area of the imaging unit 20 extends across the complete maximum transportation width 36, in particular the width of the film material 16. Optionally the width of the measuring area is wider than the maximum transportation width 36, in particular to capture additionally to the film material 16 a physical reference element indicating a position of the film material 16 with respect to the guiding unit 38, in particular the film edge location 48 of the film material 16 with respect to the guiding unit 38.

Preferably the monitoring device 10 comprises an output interface 62, in particular a display, to present at least one image 42 of the film material 16. The image 42 of the film material 16 can be a single line scan taken by the imaging unit 20 or a composition of several line scans taken by the imaging unit 20. The image 42 of the film material 16 can be a static set of line scans, in particular depicting one segment of the film material that is going to be processed to contain one unit of the product for packing, or a video stream of the imaging unit 20, that is in particular updated after each line scan. Preferentially, the imaging unit 20 is configured to take the image 42 of the film material 16 while the film material 16 is transported by the guiding unit 38, in particular while the film material 16 is moving with respect to the imaging unit 20 and the guiding unit 38. The monitoring device 10 comprises at least one evaluation unit 40 that is configured to evaluate the at least one image 42 of the imaging unit 20 regarding at least two different features 22, 24, 26, 28, 30, 32, 34, 35 of the film material 16. Preferably the evaluation unit 40 evaluates the same image 42, in particular the same line scan of the imaging unit 20, for at least two of the different features 22, 24, 26, 28, 30, 32, 34, 35 of the film material 16. Alternatively or additionally, the evaluation unit 40 evaluates at least two different images 42, in particular of the same segment of the film material 16, for at least two of the different features 22, 24, 26, 28, 30, 32, 34, 35 of the film material 16. The monitoring device 10 comprises at least one velocity sensor element, in particular an encoder 44, to measure a transportation velocity of the film material 16 through the measuring area of the sensor unit 14. For example, the encoder 44 is arranged at one of the rollers of the guiding unit 38, to measure a rotation velocity of the roller. In particular, the evaluation unit 40 determines a velocity of the film material 16 for rolling off of said roller as the transportation velocity.

Figure 2 shows a method 45 for operating the monitoring device 10. The method 45 comprises preferably an image taking step 64, in which the imaging unit 20 takes the at least one image 42, in particular at least one line scan, of the film material 16. The method 45 comprises preferably a transportation velocity measurement step 66, in which the encoder 44 measures the transportation velocity of the film material 16, in particular a conveying speed of the guiding unit 38. The method 45 comprises preferentially an evaluation step 68, in which the evaluation unit 40 evaluates the image 42, in particular in dependence of the transportation velocity. In particular, the evaluation unit 40 determines a scan distance in dependence of the transportation velocity, wherein the scan distance is a spatial distance between two segments of the film material 42, for which the evaluation unit 40 received at least one image, in particular a respective line scan, from the imaging unit 40, respectively. In the image taking step of the method 45 the imag- ing unit 20 takes images 42 as a continuous video stream. Preferably, the evaluation unit 40 sets an update interval of the imaging unit 20 in dependence of the transportation velocity, in particular such that the imaging unit 20 takes at least one image, in particular one line scan, every, 0,5mm, preferentially every 0,1mm, of film material 16 being forwarded along the transportation direction 18. The evaluation unit 40 can collect several line scans and evaluates the composed image 42 of those line scans or evaluates each line scan separately, in particular as soon as the according line scan is received by the evaluation unit 40. Preferably, the method 45 comprises at least one command step 70, in which the evaluation unit 40 sends at least one command signal to a control system of the packaging machine 12 in dependence of an evaluation of the image 42 of the film material 16. Alternatively or additionally, the evaluation unit 40 sends a warning to an operator of the packaging machine 12 in dependence of the evaluation of the image 42 of the film material 16.

Figure 3 shows an exemplary design of a film material 16 with several intended features 22, 24, 26, 28, 30, 32, 34. Most of the intended features 22, 24, 26, 30, 32, 34 are arranged in particular in a feature pattern 76, that is repeated along the transportation direction 18. The feature pattern 76 corresponds preferably to one segment of the film material 16, that is intended to pack one packing unit of the product for packing. The feature pattern 76 comprises for example a film spot 46 as a feature 22. The feature pattern 76 comprises for example the film edge location 48 as a feature 24. The feature pattern 76 comprises for example a bar code 50 as a feature 26. The feature pattern 76 comprises for example a printing 54 as a feature 30. The feature pattern 76 comprises for example a punch hole 56, in particular several punch holes, as a feature 32. The feature pattern 76 comprises for example a label 58 as a feature 34. Optionally, the film material 16 comprises a splice tape position 52 as a feature 28, which is not part of the feature pattern 76, but repeats in particular once per batch of film material 16. The feature pattern 76 extends in particular over the whole width of the film material 16 in a transverse direction 72 perpendicular to the transportation direction 18.

In the evaluation step 68 of the method 45 (cf. Fig. 2) the at least one image 42 taken by the imaging unit 20 is evaluated by the evaluation unit 40 regarding the film spot 46 of the film material 16. In the evaluation step 68 of the method 45 (cf. Fig. 2) the at least one image 42 taken by the imaging unit 20 is evaluated by the evaluation unit 40 regarding the film edge location 48 of the film material 16. In the evaluation step 68 of the method 45 (cf. Fig. 2) the at least one image 42 taken by the imaging unit 20 is evaluated by the evaluation unit 40 regarding the bar code 50 of the film material 16. In the evaluation step 68 of the method 45 (cf.

Fig. 2) the at least one image 42 taken by the imaging unit 20 is evaluated by the evaluation unit 40 regarding the splice tape position 52 of the film material 16. In the evaluation step 68 of the method 45 (cf. Fig. 2) the at least one image 42 taken by the imaging unit 20 is evaluated by the evaluation unit 40 regarding the printing 54 of the film material 16. In the evaluation step 68 of the method 45 (cf. Fig. 2) the at least one image 42 taken by the imaging unit 20 is evaluated by the evaluation unit 40 regarding the punch hole 56 within the film material 16. In the evaluation step 68 of the method 45 (cf. Fig. 2) the at least one image 42 taken by the imaging unit 20 is evaluated by the evaluation unit 40 regarding the label 58 of the film material 16. In the evaluation step 68 of the method 45 (cf. Fig. 2) the at least one image 42 taken by the imaging unit 20 is evaluated by the evaluation unit 40 regarding the damage 60 of the film material 16 (cf. Fig 1).