Method for operating a packaging machine for food products, and packaging machine

Abstract

The invention relates to a method for operating a packaging machine for food products for producing packaging at least from a lower material web and an upper material web, which enclose at least one product area in each package, in which the lower material web passes through a forming station of the packaging machine in which product area recesses are formed in the lower material web either by forming without the action of heat or by thermoforming, and after food products have been placed in the recesses the material webs are joined together to seal the product areas, wherein the lower material web comprises at least one material layer consisting of fibrous material and / or vegetable raw material or comprising fibrous material and / or vegetable raw material, and wherein prior to forming without the action of heat or prior to thermoforming the lower material web undergoes a pre-treatment in which the moisture content of the material layer is changed, in particular increased.

Description

[0001] METHOD FOR OPERATING A PACKAGING MACHINE FOR FOOD PRODUCTS, AND PACKAGING MACHINE

[0002] The invention relates to a method for operating a packaging machine for food products for producing packages from at least a lower material web and an upper material web, which enclose at least one product region of a respective package, in which the lower material web passes through a forming station of the packaging machine, in which recesses of the product regions are formed in the lower material web either by forming without the application of heat or by thermoforming, and after the introduction of food products into the recesses, the material webs are connected to one another in order to close the product regions.

[0003] The invention also relates to a packaging machine for food products, in particular for carrying out a method as disclosed herein, with a plurality of work stations arranged one behind the other along a transport direction for producing packs from at least a lower material web and an upper material web, which enclose at least one product region of a respective pack, wherein one work station is a forming station which is designed to form recesses of the product regions in the lower material web by forming without the application of heat or by thermoforming, in particular wherein a further work station is a sealing station arranged downstream of the forming station, which is designed to connect the lower material web and the upper material web to one another.

[0004] Such methods and devices are generally known to those skilled in the art. Thermoforming is the forming of a respective semi-finished product – in this case, the lower material web – at elevated temperature. Thermoforming is also referred to as hot forming or deep drawing, which is why the forming station is also referred to as a deep-drawing station. However, the invention is not limited to forming at elevated temperature, i.e., forming with the application of heat. The forming of the lower material web can also be carried out without the application of heat, i.e., not by thermoforming. Unless otherwise stated below, general terms such as "forming" and "forming station" refer to both variants of the invention, i.e., to both thermoforming and forming without the application of heat. Forming without the application of heat can be carried out, for example, by compressed air forming, by vacuum forming, or by combined compressed air and vacuum forming.Even with thermoforming, the material web can be formed by compressed air forming, by vacuum forming or by combined compressed air and vacuum forming, but only on a previously heated material web.

[0005] The material webs used to package food products are typically film webs, often comprising several layers of different plastic materials. To produce more environmentally friendly packaging, attempts have already been made to use material webs with a paper component, with a comparatively thick paper layer serving as a support and one or more comparatively thin layers of plastic supporting the food products.

[0006] However, it has been found that such a material web with a paper component does not exhibit sufficient dimensional stability after forming without heat or thermoforming, or loses this stability over time. This can be explained by the fact that the paper component of a package is significantly more susceptible to environmental influences than a purely plastic package. Transport and storage of the packages after production mean that the packages are exposed to environments with different temperatures, where humidity can vary greatly. The paper can therefore absorb moisture and lose stiffness. This can lead to deformation of the package and thus to poorer product presentation.Such adverse deformations can be promoted by mechanical stresses on the packages, for example during transport and storage in a vertical position, as well as by stresses inherent in the upper material web to which the lower material web is firmly connected during the manufacture of the packages.

[0007] The object of the invention is to improve a method for operating a packaging machine and a packaging machine of the type mentioned at the outset in such a way that the plastic content of the packages can be reduced and at the same time a high dimensional stability of the packages can be ensured.

[0008] This problem is solved by the features of the independent claims.

[0009] In the method according to the invention, it is provided that the lower material web comprises at least one material layer which consists of fiber and / or vegetable raw material or comprises fiber and / or vegetable raw material, and that before forming without the application of heat or thermoforming, the lower material web is subjected to a pretreatment in which the moisture content of the material layer is changed, in particular increased.

[0010] In the packaging machine according to the invention, it is provided that the lower material web comprises at least one material layer which consists of fiber and / or vegetable raw material or comprises fiber and / or vegetable raw material, and that at least one pretreatment device is provided which is arranged upstream of the forming station or at least partially integrated into the forming station and is designed to subject the lower material web to a pretreatment in which the moisture content of the material layer is changed, in particular increased.

[0011] Multiple pretreatment devices or a single pretreatment device with multiple stages can be provided. This allows for multi-stage pretreatment. For example, several staggered and individually activated or switchable spray bars can be provided to dispense a treatment agent. This allows the packaging machine to enable flexible pretreatment that can be adapted to the respective application.

[0012] As already mentioned at the beginning, the forming of the material web can take place at an elevated temperature, i.e., forming can take place with the application of heat to the material web. Alternatively, the forming of the lower material web can also take place without the application of heat. In the latter case, the forming station used can be designed such that it does not heat the material web, i.e., it can have neither an integrated nor an upstream heating station that serves to heat the material web. The forming station can, for example, be designed such that it accomplishes the forming without the application of heat, through compressed air forming, through vacuum forming, or through a combination of compressed air and vacuum forming.

[0013] The lower material web can be single-layered, i.e. consist of exactly one layer, namely the fabric layer. Alternatively, the lower material web can be multi-layered, i.e. have several material layers that are bonded together during production. Each of the multiple layers can be a fabric layer, so that the lower material web is a fibrous web without a film layer, i.e. without a plastic layer. Depending on the nature of the material layer in question and the properties of the food products to be packaged, a fabric layer can be suitable - at least after passing through a forming station - to serve as a support for the food products. Alternatively, in a multi-layer lower material web, it can be provided that an upper layer comprises one or more plastic film layers and a lower layer comprises one or more fabric layers. The top side of the plastic layer orThe top plastic layer then serves as a support surface for the food products to be packaged, while the underside of the fabric layer or the bottom fabric layer forms the outside of the lower material web and thus the lower outside of each finished package.

[0014] When the present disclosure refers to a layer of plastic or a film layer of plastic, plastic does not mean a material that consists of or comprises plastic fibers.

[0015] If the fabric layer consists of or comprises fiber, the fiber primarily comprises fibers of plant origin. The fiber can include wood pulp, other cellulose, or raw materials obtained from the recycling of paper, cardboard, or paperboard. The fabric layer can consist of or comprise paper, cardboard, or paperboard.

[0016] It was surprisingly found that packages made of fibrous material or with a fibrous material content have a high dimensional stability even after a long time and even after comparatively robust handling during transport and storage if the material web in question is subjected to a pretreatment before forming without the application of heat or thermoforming, in which the moisture content of the material layer is influenced, regardless of whether the material web comprises one or more plastic films in addition to the at least one material layer or not.

[0017] The fiber material or - if the fabric layer comprises several different materials - a fiber material of the fabric layer can comprise plastic fibers. A mixed material of plastic fibers and fibers of plant origin is particularly preferred. In particular, the fabric layer can comprise a mixture of plastic fibers and paper, cardboard, or paperboard. The plastic fibers, on the one hand, and the paper, cardboard, or paperboard, on the other hand, can each form a partial layer of the fabric layer, with the partial layers lying on top of one another. The partial layers are preferably connected to one another in such a way that they can be separated again after use with relatively little effort, which simplifies recycling.

[0018] The fabric layer can consist of or comprise plant-based raw materials. This raw material can be fiber or it can comprise fiber, as already mentioned above. However, this is not mandatory: The plant-based raw material does not have to be or comprise fiber. For example, the plant-based raw material can be or comprise starch, such as corn starch. The statements made in the previous paragraph in connection with fiber apply accordingly to plant-based raw materials.

[0019] It is also possible for the fabric layer to comprise both fibrous material and plant raw material not comprising any fibers, i.e. the fabric layer can be a multi-material layer made of different materials, wherein the materials can be mixed with one another or at least substantially separated from one another, for example separated from one another in such a way that the two materials form superimposed partial layers of the fabric layer.

[0020] Furthermore, it can be provided that the material layer comprises several different fiber materials and / or several different plant-based raw materials. The different materials can be mixed with one another or at least substantially separated from one another, for example, separated from one another in such a way that the two materials form superimposed partial layers of the material layer. Depending on the initial state in which the lower material web is fed to the thermoforming station, the pretreatment of the lower material web can be drying to reduce the initial moisture content of the material layer. Such situations and applications are fundamentally possible.

[0021] In most cases, however, the lower material web will be in an initial state in which the fabric layer has a moisture content whose increase results in an improvement in dimensional stability after forming without heat or thermoforming.

[0022] In preferred embodiments of the invention, it is therefore provided that the pretreatment increases the moisture content of the material layer compared to an initial state.

[0023] The pretreatment can be carried out in such a way that the fabric layer has a homogeneous or at least approximately homogeneous moisture distribution. Alternatively, the pretreatment can be carried out in such a way that the moisture content is higher on the outer side of the fabric layer than in the inner areas of the fabric layer.

[0024] The pretreatment may simply involve moistening the outer side of the fabric layer. Alternatively, it is possible for the pretreatment to involve thoroughly moistening the fabric layer. The specific type of pretreatment can be selected depending on the respective application, for example, depending on the material or material mixture used, the thickness of the fabric layer, or the process parameters of the forming station or thermoforming station, in particular the temperature to which the lower material web is heated during thermoforming. Further advantageous embodiments of the method according to the invention are specified below.

[0025] In some embodiments of the method, the pretreatment on the packaging machine can be carried out during the ongoing operation of the packaging machine immediately before forming without the application of heat or thermoforming or immediately after unwinding the lower material web, e.g. from a supply roll.

[0026] The pretreatment can take place on the way of the lower material web from a supply roll to the forming station or in the forming station.

[0027] Pre-treatment preferably takes place in an area downstream of a supply roll, i.e. directly downstream of the unwinding station, and in particular upstream of a first deflection of the material web. The material web runs straight here and - apart from a reduction in the diameter of a supply roll, which may affect the position of the material web - always in the same position and always at the same web speed. Thus, essentially consistently defined conditions prevail for pre-treatment. This would not be the case, for example, if the pre-treatment were located in the area of ​​a multiple deflection device with one or more movable dancer rolls for the material web located between the supply roll and the forming station.Such early pretreatment is also advantageous because it allows more time for the pretreatment to take effect before forming in the forming station, in particular for the absorption of a liquid treatment agent into the material layer.

[0028] According to some developments of the process, the pre-treatment can take place when the lower material web is stationary or during a pulling movement of the lower material web. In practice, packaging machines usually work in cycles: During a respective work cycle, the upper material web and the lower material web are each stationary, with a respective work process being carried out at the individual work stations of the packaging machine. During a movement cycle following a respective work cycle, the upper material web and the lower material web are moved further in the transport direction of the packaging machine, which is also referred to as pulling. In practice, pulling often only lasts between a fraction of a second, e.g. 0.5 seconds, and one second or a few seconds. This depends, among other things, on the pulling length, which in practice can typically be between 300mm and 1,000mm.

[0029] In some embodiments of the invention, the pretreatment of the lower material web is carried out by applying a treatment agent to the fabric layer. The treatment agent is, in particular, a fluid, especially water. Other liquids or mixtures of different liquids can be used alternatively.

[0030] The treatment agent can comprise one or more fragrances and / or flavorings. In this way, the fabric layer and thus the finished packages can be given an additional property, namely a property that appeals to the sense of smell of the package buyers. This property can therefore be used as a special marketing tool. The fragrance(s) and / or flavoring(s) can be contained in the treatment agent. It is also possible to apply an additive containing the flavoring(s) and / or additive(s) in addition to the treatment agent. The additive can - like the treatment agent - be, for example, a liquid, a vapor, a mist, or an aerosol. The additive can also consist solely of the flavoring(s) and / or additive(s).The treatment agent can be applied in different ways, depending, for example, on the specific design of the packaging machine, the nature of the lower material web or the process parameters of the forming station.

[0031] In some embodiments, it may be provided that the treatment agent is applied to the fabric layer in liquid form or in the form of vapor, mist or aerosol.

[0032] The treatment agent can be applied to the fabric layer by passing the lower material web through a treatment agent bath or through a pretreatment area containing the treatment agent in the form of vapor, mist, or aerosol. The pretreatment area can have several zones that differ from one another in terms of the type of pretreatment, e.g., by different concentrations of the respective treatment agent or by different treatment agents.

[0033] In some embodiments, it may be provided that the treatment agent is applied to the fabric layer by contact or without contact.

[0034] The treatment agent can be applied to the fabric layer using an application device. The application device can be effective through contact with the fabric layer or can operate contactlessly.

[0035] In some embodiments of the invention, it may be provided that the treatment agent is dispensed in the form of individual, flying quantities of liquid, sprayed in liquid form or ejected as vapor.

[0036] According to some embodiments of the method according to the invention, it can be provided that the treatment agent is dispensed or ejected in the direction of the underside of the fabric layer forming the underside of the lower material web.

[0037] The lower material web can be guided on its path to the forming station in such a way that the material layer is on top for at least one or more sections of the path, i.e., an outer side of the lower material web formed by the material layer points upwards—vertically or diagonally—so that the treatment agent can be applied from above using gravity. The treatment agent can therefore be applied, for example, by sprinkling, i.e., the treatment agent does not have to be ejected or sprayed upwards against gravity, which requires increased energy expenditure.

[0038] According to some embodiments, it can be provided that at least part of the heat required for thermoforming is supplied to the lower material web during the pretreatment. In particular, it can be provided that the heat supply occurs simultaneously with the application of the treatment agent. It can be provided that the heat supply occurs through the application of the treatment agent.

[0039] The pretreatment can therefore be used for heating the lower material web, which is required anyway. A heating station integrated into the forming station or upstream of the forming station can be supported or even replaced by the pretreatment. For example, the lower material web can be passed through a pretreatment area containing the treatment agent in the form of steam, or the treatment agent can be ejected in the form of steam, whereby part of the energy used to evaporate the treatment agent can be transferred to the lower material web in the form of heat energy by means of the steam. In principle, it is possible for the pretreatment to be carried out with preset parameters that remain unchanged during a particular application, whereby the presets are based, for example, on experience.

[0040] According to some developments of the invention, it can be provided that process parameters of the pretreatment and / or the forming station are set or changed depending on properties, in particular moisture content and / or temperature, of the material layer, which are determined before the pretreatment and / or after forming without heat exposure or thermoforming and / or during forming without heat exposure or thermoforming. These process parameters can be changed during operation of the packaging machine, specifically based on the properties of the material layer determined during operation. The process parameters of the forming station can be, for example, the heating temperature, the heating duration, the forming pressure and / or the forming duration.The process parameters of the pretreatment can be, for example, the temperature of the treatment agent or the amount of treatment agent to be applied per unit of time or unit area of ​​the lower material web.

[0041] According to further embodiments of the invention, the pretreatment and / or the forming station can be incorporated into a control system in which properties, in particular moisture content and / or temperature, of the material layer after forming without heat exposure or thermoforming are determined as actual values ​​and compared with predetermined target values, and in which one or more process parameters of the pretreatment and / or the forming station are manipulated variables of the control system. Regarding the possible process parameters for this, reference is made to the above explanations.

[0042] According to one example, the moisture content of the fabric layer can be measured before pretreatment, and based on this measurement, the pretreatment process parameters can be adjusted, for example, the amount of treatment agent to be applied and the application time. Following pretreatment, for example, after each advance movement of the lower material web, the moisture content can then be measured to check whether the pretreatment has achieved a specific target value.

[0043] According to further embodiments, it can be provided that different regions of the material layer are pretreated differently. The required dimensional stability of a package can depend on how strongly the lower material web or the material layer has been deformed in the forming station, i.e. the desired dimensional stability can depend on the degree of deformation in a particular region of the package, in particular on the strength of any curvature of the material in this region. Since these geometric parameters are known for a particular application, adaptation to the specified degree of deformation of a particular region of the material layer can be achieved by means of a correspondingly targeted, locally varying pretreatment.

[0044] In some embodiments of the invention, it can be provided that the pretreatment is subjected to process control. For example, a measure of the moisture content of the material layer and / or of the distribution of the moisture in the material layer can be determined by contact or contactless means using a detection device. A camera, for example, can serve as the detection device. The detection device can be arranged between the pretreatment location and the forming station. Such process control can detect malfunctions. For example, if an area of ​​the material layer that is not moistened or is only moistened to a very small extent is detected, it can be concluded that the nozzle for dispensing treatment agent that is assigned to this area of ​​the material layer is defective or blocked.Alternatively or additionally, the moisture content of the material layer can be measured after pretreatment to adjust the process parameters of the forming station, whereby parameters such as heating temperature, heating time, forming pressure and / or forming time are then adjusted at the forming station depending on these measured values.

[0045] Alternatively or additionally, the temperature in the lower material web can be measured before pretreatment, after which the temperature of the treatment agent and the application time can be adjusted. Following pretreatment, for example, during or after the next advance movement of the lower material web, it can then be checked whether a specified target temperature value for the lower material web has been reached.

[0046] Furthermore, on the basis of the temperature of the lower material web measured following the pretreatment, the process parameters of the forming station can be adjusted, as already explained above, ie, for example, the heating temperature, heating time, forming pressure and / or forming time can be adjusted at the forming station.

[0047] In an alternative, simpler control design, measurements on the fabric layer or lower material web prior to pretreatment can be omitted. Subsequent control can then be performed by measuring actual values ​​for the temperature of the lower material web and the moisture content of the fabric layer following pretreatment, comparing them with target values, and then adjusting process parameters accordingly if necessary to achieve the target values.

[0048] Possible further developments of the packaging machine according to the invention are explained below. In order to apply a treatment agent, in particular a fluid, e.g., water, to the fabric layer, the pretreatment device located upstream of the forming station or at least partially integrated into the forming station can be designed to apply the treatment agent in liquid form or in the form of vapor, mist, or aerosol.

[0049] According to some embodiments, the pretreatment device can be arranged on a supply roll formed by a wound lower material web, on the path of the lower material web from the supply roll to the forming station, or at least partially in the forming station. To guide the lower material web from the supply roll to the forming station, an arrangement of several deflection rollers can be provided, which can include one or more so-called dancer rollers. For example, the pretreatment device can be provided in the region of such a guide for the lower material web.The individual components of the pretreatment device can be integrated into this area of ​​the guide for the lower material web, whereby a somewhat decentralized integration of the pretreatment device is also possible, in which different components of the pretreatment device are arranged at different positions along the path of the lower material web between the supply roll and the forming station.

[0050] As already mentioned elsewhere, the treatment agent can be applied to the fabric layer in different ways.

[0051] Thus, according to some embodiments, it can be provided that the pretreatment device comprises a treatment agent container containing the treatment agent in liquid form, or an at least partially enclosed treatment space containing the treatment agent in the form of vapor, mist or aerosol, wherein the lower material web can be passed through the treatment container or the treatment space.

[0052] In this case, it is only necessary to provide a volume—in particular, a container or room—and fill it with the treatment agent in a specific form or state of aggregation, so that the lower material web only needs to be passed through this volume to influence the moisture content of the material layer of the lower material web accordingly. Active application devices such as ejection nozzles, etc., can be dispensed with in this case.

[0053] According to some embodiments of the invention, it can be provided that the pretreatment device comprises an application device which is designed to apply the treatment agent to the fabric layer by contact or without contact.

[0054] Contact treatment can be achieved, for example, by passing the lower material web over part of the circumference of an application roller or through a gap formed by two rollers, one of which is an application roller. The respective application roller can, for example, be partially immersed in the treatment agent in liquid form, so that when the application roller rotates, it conveys the treatment agent across its surface and thus transfers it to the contacting material layer of the lower material web.

[0055] According to some embodiments, contactless application of treatment agent can be achieved by the application device being designed to dispense the treatment agent in the form of individual, flying quantities of liquid, to spray it in liquid form, or to expel it as vapor. The dispensing, spraying, or expulsion of the treatment agent can be carried out more or less randomly in such a way that an atmosphere is created in an area through which the lower material web is passed, in which sufficient treatment agent is present to influence the moisture content of the material layer in the desired manner.

[0056] Alternatively, a targeted application can be carried out in that the application device is designed to dispense or eject the treatment agent in the direction of the underside of the fabric layer forming the underside of the lower material web.

[0057] Depending on the orientation of the underside of the fabric layer in the room at the location where the treatment agent is applied, the targeted application can be carried out in a horizontal direction, in a vertical direction downwards, in a vertical direction upwards or diagonally upwards or diagonally downwards.

[0058] The application device can be designed and the path of the lower material web can be such that the application device is partially wrapped by the material web. For example, the material web, together with the deflection rollers that determine its path, can form a chamber, e.g., U-shaped in cross-section, around the area where the application takes place. The treatment agent can be dispensed, for example, sprayed, in a vertical direction upwards or to the side. This has the advantage that dripping treatment agent reaches a lower section of the material web, thus "pre-saturating" the material web and adhering to it.

[0059] The application device can have at least one dispensing opening for the treatment agent. In particular, the dispensing opening can be formed by a nozzle. Furthermore, it can be provided that the application device is connected to a treatment agent supply. In this case, it can be provided in particular that at least one container is provided for the treatment agent supply, which container is arranged on or in the packaging machine and is in particular exchangeable and / or refillable. In particular, a plurality of containers can be provided which are connected to the application device in such a way that the contents of the containers are used up one after the other and the containers can be exchanged and / or refilled independently of one another. Downtimes for the packaging machine caused by the pretreatment can be prevented in this way.

[0060] According to further embodiments of the invention, the application device can comprise a carrier extending in the transverse direction, on which a plurality of discharge openings, in particular a plurality of nozzles each forming a discharge opening, and supply lines for the treatment agent leading to the discharge openings are attached.

[0061] According to further embodiments, it can be provided that the application device has a plurality of dispensing openings which can be controlled independently of one another.

[0062] Regardless of the specific design of a particular dispensing opening or the number of dispensing openings, it can be provided that the dispensing openings can each be specifically either opened or closed by means of a control unit, e.g. by means of a controllable valve that is assigned to the particular dispensing opening or to a group of dispensing openings comprising the particular dispensing opening. Alternatively or additionally, it can be provided that the dispensing direction of treatment agent can be changed by means of the control unit, e.g. by adjusting a nozzle forming the dispensing opening. If several dispensing openings are provided and these can be controlled independently of one another, it is possible to achieve particularly flexible adaptation to the respective application. For example, depending on the respective application, only some of the dispensing openings basically provided can be used.It is also possible, for example, to provide different treatment agents and, depending on the specific application, to apply either one treatment agent through one or more of the dispensing openings or a different treatment agent through one or more of the other dispensing openings. Furthermore, it is also possible to use several dispensing openings simultaneously, but to apply different treatment agents through them—thus simultaneously.

[0063] According to further embodiments, the treatment agent can comprise a plurality of components, in particular separately stored components, which can be combined before or during dispensing through a respective dispensing opening. For example, one of the components can be actively supplied to the respective dispensing opening, in particular by means of a pump, wherein the flow of this component in the region of the dispensing opening can convey the other component of the treatment agent by suction, utilizing the Venturi principle, so that a mixture of the multiple components is provided as the treatment agent.

[0064] As already mentioned, water, for example distilled water, can be used as a treatment agent. Instead of water or as an additional treatment agent component, liquids that have an impregnating or sealing effect on the fabric layer can be used. This can create a protective layer, for example, for a printed image on the visible underside of the fabric layer. A multi-component treatment agent can also be composed such that it is absorbed by the fabric layer better or faster than water. The treatment agent, or at least one component of the treatment agent, can, for example, be surfactant-based in order to reduce surface tension.It is also possible to use a treatment agent or at least a component of the treatment agent that is designed to be activated by subsequent processes in the packaging machine, for example, by friction, temperature change, pressure, or vacuum application, whereby this activation is accompanied by a change in at least one property. For example, the treatment agent or the treatment agent component can harden as a result of such activation, further increasing the dimensional stability of the material layer and creating a protective layer on the outer side of the finished packaging formed by the material layer.

[0065] According to further embodiments of the invention, a control device controlling the operation of the packaging machine can be provided, which is designed to carry out a control of the pretreatment device and / or the forming station and / or a process control, in particular according to the possible embodiments described in the context of this disclosure.

[0066] Consequently, the control device can assume all tasks related to the pretreatment device. Alternatively, a separate control unit can be provided for the pretreatment device, which can either be integrated into the packaging machine control system or designed as a separate unit that can be connected to the packaging machine control system either wired or wirelessly. Regardless of the specific design, an application device of the pretreatment device, which is connected to a treatment agent supply, can be arranged at an optimally suitable location on or in the packaging machine in such a way that the or each discharge opening is positioned and / or aligned in the desired manner. The application device can be connected to the treatment agent supply, which can comprise at least one container, for example, via one or more flexible lines.In this way, the application device can be flexibly adapted to the respective structural conditions of the packaging machine and integrated into it.

[0067] If, according to some embodiments, the application device comprises an elongated support on which a plurality of discharge openings and supply lines for the treatment agent leading to the discharge openings are mounted, then the support can be designed, for example, as an elongated nozzle bar. Such a support can, for example, be removable without tools for easy cleaning or replacement.

[0068] Purely as an example, it should be mentioned that tests have shown that good results, i.e. packages with high dimensional stability, were achieved when a total basis weight of about 300g / m A2 lower material web with an upper plastic layer and a lower paper layer, water was sprayed onto the paper layer, namely a quantity of about 0.0022ml / cm A 2 during the advance of the lower material web, lasting approximately 0.5 seconds for a pull-off process with a pre-draw length of approximately 40 mm. It was found that the water requires approximately 30 seconds to penetrate the material layer. The temperature in the forming station was between 65 and 85°C. The possible embodiments of the invention explained above each represent independent aspects of the invention, for which protection is claimed independently of other aspects.

[0069] The invention is described below by way of example with reference to the drawing, in which:

[0070] Fig. 1 schematically shows a packaging machine according to the invention in a side view, and

[0071] Fig. 2 to 4 each schematically show a possible embodiment of a pretreatment device according to the invention.

[0072] A possible embodiment of a packaging machine according to the invention is described below with reference to Fig. 1. This embodiment, with the exception of the pretreatment according to the invention, is generally known to those skilled in the art. For the sake of simplicity, in the following description, the lower material web 23 is also referred to as the bottom film according to conventional terminology, although it comprises a material layer 33, e.g., a paper layer.

[0073] The packaging machine V shown in Fig. 1, operating in a transport direction T, comprises a machine frame 47. A transport chain 27, shown only schematically here at the upstream end of the machine, is guided on a left side frame and a right side frame of the machine frame 47. The two transport chains 27 together form a transport device for a bottom film 23 pulled from a supply roll 23a.

[0074] The machine comprises a plurality of work stations following one another in the transport direction T, namely a forming station 11, also referred to as a deep-drawer or thermoformer, an insertion station 13 for products 10 to be packaged, a feed station 14 for a top film 25 pulled off a supply roll 25a, a sealing station 15, a labelling and / or printing station 16, a transverse cutting station 17 and a longitudinal cutting station 19. In the embodiment according to Fig. 1, the forming station 11 is therefore a thermoformer, although this is not mandatory; in an alternative embodiment, the forming can take place without the application of heat.

[0075] The products 10 to be packaged are food products, here in the form of so-called portions, each comprising several slices that were previously separated from a loaf- or bar-shaped food product, such as sausage, cheese, ham, or meat, using a food slicer (not shown). The slicer and the packaging machine can form a continuous production line.

[0076] The operation of the packaging machine V, including the aforementioned workstations, is controlled by a central control device 41. This can also control the slicer or be connected to a control device of the slicer. Furthermore, the packaging machine V is preferably provided with an operating device 45, which includes, for example, a touchscreen, on which all necessary information can be displayed to an operator and the operator can make all necessary settings before and during operation of the machine.

[0077] The structure and functionality of the workstations mentioned are generally known to the expert, so they will not be discussed in detail here.

[0078] At the forming station 11, which comprises an upper tool 11a and a lower tool 11b, depressions 29, also referred to as troughs, are formed in the bottom film 23 during a deep-drawing process. The aforementioned portions 10 are inserted into these depressions 29 at the insertion station 13. The insertion station 13 here comprises a so-called inserter, of which two endless conveyor belts 13a, 13b are shown. Alternatively or additionally, the insertion station 13 can comprise a robot 50, also shown schematically here, e.g., in the form of a so-called "picker," which can be designed as a delta robot with a gripper comprising two scoops, each of which jointly holds a portion 10. Such robots and their use in handling foodstuffs, in particular in inserting portions into packaging depressions, are generally known to those skilled in the art, which is why further explanations are not necessary here.

[0079] Subsequently, the bottom film 23, provided with the filled recesses 29, and the top film 25 are fed to the sealing station 15, which comprises an upper tool 15a and a lower tool 15b. The top film 25 and the bottom film 23 are joined together by means of these tools 15a, 15b. This seals the recesses 29 and thus the product areas 20 enclosed by the top film 25 and bottom film 23, i.e., the packages 21 formed by the top film 25 and bottom film 23. Sealing points 43, also referred to as sealing seams, running transversely to the transport direction T, are schematically indicated in Fig. 1. The term "package" is also commonly used instead of "packaging."

[0080] Following the sealing station 15, the packages 21 are still connected by the top film 25 and the bottom film 23, and therefore still need to be separated, which takes place at the aforementioned separation stations 17, 19. In the embodiment shown here, the packages 21 are labeled and / or printed at the labeling and / or printing station 16 before being separated. Labeling and printing can also take place at separate stations.

[0081] Downstream of the separation stations 17, 19, further conveyor belts and / or workstations can be provided, for example, a scale for checking the weight of the packages 21. Applications can differ from one another, for example, with regard to the type of products 10 to be packaged, the size / shape of the recesses 29 in the longitudinal and / or transverse direction, or with regard to a format set. A format set here generally refers to a group of items, in particular both portions 10 and recesses 29 or packages 21, which are handled as a whole—i.e., by format set—and which differ from one another in particular with regard to the number and spacing of items in the longitudinal and transverse directions.

[0082] For example, per work cycle of the packaging machine, a packaging format or format set of 3 x 4 (3 in the transverse direction and 4 in the longitudinal direction) recesses 29 or other product receptacles can be formed in the forming station 11, a format set of 3 x 4 correspondingly arranged products 10 can be inserted into a respective format set of recesses 21 at the insertion station 13, and a respective format set of 3 x 4 recesses 29 filled with products 10 can be sealed at the sealing station 15. The same applies to the labeling and / or printing station 16.

[0083] In principle, an arbitrarily dimensioned N x M format set can be created, with N >= 1 and M >= 1 .

[0084] In this exemplary embodiment, the pretreatment according to the invention relates to the lower material web 23, also referred to above as the bottom film, which, according to the enlarged detailed view on the far right in Fig. 1, comprises an upper layer 31 made of plastic and a lower layer 33 made of fiber and / or plant-based raw material. The material layer 33 can be formed, for example, from paper. The upper plastic layer 31 can itself be formed from a single or multi-layered material and, in the case of a multi-layered design, can comprise several films made of the same plastic or of different plastics.On its way from the supply roll 23a to the forming station 11, the lower material web 23 passes through a pretreatment device 55, shown only schematically here, which in this embodiment serves to moisten the paper layer 33 in order to increase the moisture content of the paper layer 33 for the subsequent thermoforming in the forming station 11 compared to the moisture content that the paper layer 33 has in the initial state in the supply roll 23a.

[0085] Also shown in Fig. 1 is a detection device 53 in the form of a camera, with which process control can be carried out, as has already been described elsewhere using several examples. The camera 53 and associated image recognition software are set up to determine a measure of the moisture content of the paper layer 33. Alternatively or additionally, this process control can be set up to determine a measure of the distribution of the moisture in the plane of the paper layer 33. The positioning of the camera 53 in Fig. 1 above the lower material web 23 is to be understood purely schematically. As already mentioned elsewhere, the lower material web 23 can actually be guided such that the paper web 33 points vertically upwards or diagonally upwards in sections, so that it can be detected by a camera 53 arranged above the material web 23.Alternatively, the camera can be arranged below the material web 23.

[0086] Figures 2, 3 and 4 show, by way of example and purely schematically, different possibilities for applying liquid, for example water, to the material layer of the lower material web 23 by means of a pretreatment device 55 arranged downstream of the supply roll 23a.

[0087] 2 and 3, the pretreatment device 55 comprises a container 57 in which a certain amount of water is located. In the embodiment of Fig. 2, the material web 23 is guided through this water bath with the help of deflection rollers 69. In the embodiment of Fig. 3, the material web 23 is guided through a gap formed by two rollers 71, 73, which is located above the water bath. The lower roller 73 is immersed in the water bath so that its surface is wetted and, upon rotation of the lower roller 73, transfers the water to the paper layer forming the lower layer of the material web 23, in order to moisten the paper layer 33.

[0088] One possibility for moistening the paper layer 33 of the lower material web 23 without contact is shown by way of example in Fig. 4. The pretreatment device 55 comprises an elongated application device 51 which extends transversely to the direction of movement of the material web 23 across its entire width. On an elongated support 65 of the application device 51, a plurality of nozzles 61 are attached, distributed in the direction of extension, of which nozzles 61 are provided with the reference numeral 61 in Fig. 4 for the sake of simplicity. The front end of each nozzle 61 forms a discharge opening 59 from which a respective treatment agent, for example distilled water, can be sprayed or discharged as a result of individual, flying quantities of liquid.

[0089] The supply of the liquid treatment agent to the nozzles 61, shown schematically in Fig. 4, takes place, for example, via a supply line 67, which runs in or on the application device 51 and from which individual line sections branch off, leading to the nozzles 61. Controllable valves (not shown here) can be provided, which can be controlled individually or in groups in order to control the release of treatment agent for the nozzles 61 individually or in groups, ie to specifically release or prevent it.

[0090] It has already been mentioned elsewhere that different areas of the paper layer 33, in particular with regard to the transverse direction, can be pretreated differently in order to achieve, for example, an adaptation of the pretreatment to a respective degree of deformation of the depressions 29 to be produced in the forming station 11 (cf. Fig. 1).

[0091] For this purpose, the nozzles 61 can be divided into groups, each group comprising several, in particular directly consecutive, nozzles 61. Furthermore, the number of active nozzles 61 per group can be varied, particularly depending on the amount of treatment agent to be applied, thus allowing for targeted adjustment.

[0092] In addition, it may be possible to align the nozzles 61 manually or in a controlled manner in order to be able to specifically adjust the discharge direction of the treatment agent for each nozzle 61.

[0093] The supply line 67 of the application device 51 is connected to a container serving as a treatment agent supply 63, with the interposition of a controllable pump 77, by means of which the treatment agent is conveyed from the supply 63 to the nozzles 61.

[0094] A control unit 75 is provided for controlling the pretreatment device 55 during operation of the packaging machine, which is shown schematically as a separate unit in Fig. 4. This control unit 75 can form a physically and / or functionally separate unit of the packaging machine control system and can therefore be integrated into it. The control unit 75 can, for example, represent a hardware and / or a software module, for example in the sense of a separate application within the control device 41. Alternatively, it is possible to provide the control unit 75 for the pretreatment device 55 spatially separated from the packaging machine control system 41 and to connect it wirelessly or wired to this control device 41. As Fig. 4 shows, the control unit 75 is connected, among other things, to the supply 63, for example to measure the amount of treatment agent still present therein, and to the pump 77, for exampleto control the amount of treatment agent to be supplied to the application device 51 per unit of time, and connected to the application device 51 in order to control the operation of the nozzles 61. The control of the pretreatment device 55 can, in a simple implementation, be independent of the operation of the packaging machine, for example by permanently dispensing a certain amount of treatment agent via all nozzles 61. However, the pretreatment can also be carried out as a function of the operation of the packaging machine and on the basis of operating information such as, in particular, measured properties, in particular of the material layer 33 of the material web 23. Possible embodiments of a process control and a control system, in which the pretreatment and / or the forming station 11 (cf. Fig. 1) can be included, have already been discussed elsewhere, to which reference is hereby made.

[0095] List of reference symbols

[0096] 10 Product

[0097] 11 Forming station

[0098] 11 a Upper tool of the forming station

[0099] 11 b Lower tool of the forming station

[0100] 13 Feeding station

[0101] 13a Conveyor belt

[0102] 13b Conveyor belt

[0103] 14 Feed station

[0104] 15 Sealing station

[0105] 15a Upper part of the sealing station

[0106] 15b Lower part of the sealing station

[0107] 16 labeling stations

[0108] 17 Separation station (transverse direction)

[0109] 19 Separation station (longitudinal direction)

[0110] 21 pack

[0111] 23 lower material web

[0112] 23a Supply roll

[0113] 25 upper material web

[0114] 25a supply roll

[0115] 27 Transport device (transport chain for lower material web)

[0116] 29 Deepening

[0117] 31 upper layer

[0118] 33 bottom layer, fabric layer, paper layer

[0119] 41 Control device

[0120] 43 Sealing seam

[0121] 45 Control unit

[0122] 47 Machine frame

[0123] 50 robots

[0124] 51 Application device

[0125] 53 Recording device

[0126] 55 Pretreatment facility

[0127] 57 containers

[0128] 59 Discharge opening

[0129] 61 nozzle

[0130] 63 Treatment agent supply

[0131] 65 carriers

[0132] 67 supply line

[0133] 69 pulley

[0134] 71 upper roller

[0135] 73 lower roller

[0136] 75 Control unit

[0137] 77 Pump

Claims

Claims: A method for operating a packaging machine (V) for food products (10) for producing packages (21) consisting of at least a lower material web (23) and an upper material web (25) enclosing at least one product area (20) of a respective package (21), wherein the lower material web (23) passes through a forming station (11) of the packaging machine (V), in which recesses (29) of the product areas (20) are formed in the lower material web (23) either by forming without heat or by thermoforming, and after the placement of food products (10) into the recesses (29), the material webs (23, 25) are joined together to close the product areas (20), characterized in that the lower material web (23) comprises at least one layer (33) consisting of fiber and / or plant raw material.and that, prior to forming without heat or thermoforming, the lower material web (23) is subjected to a pretreatment in which the moisture content of the material layer (33) is changed, in particular increased. Method according to claim 1, wherein the lower material web (23) is multilayered and comprises at least one upper layer (31) made of plastic and at least one material layer (33) as the lower layer. A method according to claim 1 or 2, wherein the underside of the material layer (33) forms the lower outer surface of the lower material web (23). A method according to any one of the preceding claims, wherein the pretreatment on the packaging machine (V) takes place during the ongoing operation of the packaging machine (V) immediately before forming without the application of heat or before thermoforming, or immediately after unwinding the lower material web, and / or wherein the pretreatment takes place with the lower material web (23) stationary or during a pre-drawing movement of the lower material web (23). A method according to any one of the preceding claims, wherein the pretreatment takes place on the path of the lower material web (23) from a supply roll (23a) to the forming station (11), in particular in a region immediately after the supply roll (23a) or in the forming station (11).A method according to any one of the preceding claims, wherein the pretreatment is carried out by applying a treatment agent, in particular a fluid, for example water, to the material layer (33), particularly wherein the treatment agent or an additive applied in addition to the treatment agent comprises one or more fragrance and / or flavoring substances. A method according to any one of the preceding claims, wherein the treatment agent is applied in liquid form or in the form of vapor, mist or aerosol. A method according to any one of the preceding claims, wherein the treatment agent is applied by passing the lower material web (23) through a treatment agent bath or by applying the treatment agent in the form of is passed through the pretreatment area containing vapor, mist, or aerosol. A method according to any one of the preceding claims, wherein the treatment agent is applied by contact or without contact.

0. A method according to any one of the preceding claims, wherein the treatment agent is applied by dispensing the treatment agent in the form of individual, flying quantities of liquid, spraying it in liquid form, or emitting it as vapor.

1. A method according to any one of the preceding claims, wherein the treatment agent is dispensed or emitted in the direction of the underside of the material layer (33) forming the underside of the lower material web (23). 2.A method according to any one of the preceding claims, wherein at least a portion of the heat required for thermoforming is supplied to the lower material web (23) during pretreatment, in particular wherein the heat supply occurs simultaneously with, and especially by, the application of, treatment agents.

3. A method according to any one of the preceding claims, wherein process parameters of the pretreatment and / or the forming station (11) are set or changed depending on properties, in particular moisture content and / or temperature, of the material layer (33), which are determined before pretreatment and / or after forming and / or during forming without heat or thermoforming without heat or after thermoforming. A method according to any of the preceding claims, wherein the pretreatment and / or the forming station (11) are incorporated into a control system in which the properties, in particular moisture content and / or temperature, of the material layer (33) after forming without heat or after thermoforming are determined as actual values ​​and compared with predetermined target values, and in which control variables are formed from one or more process parameters of the pretreatment and / or the forming station (11). A method according to any of the preceding claims, wherein different areas of the material layer (33), in particular with respect to the transverse direction, are pretreated differently, in particular to adapt the pretreatment to a respective degree of deformation of the recesses (29).A method according to one of the preceding claims, wherein the pretreatment is subject to process control, in particular wherein a measure of the moisture content of the material layer (33) and / or the distribution of moisture in the material layer (33) is determined by contact or non-contact means of a detection device (53), preferably a camera. A packaging machine (V) for food products (10), in particular for carrying out a method according to one of the preceding claims, with several workstations arranged one after the other along a transport direction (T) for producing packages (21) from at least a lower material web (23) and an upper material web (25) which enclose at least one product area (20) of a respective package (21), wherein a workstation is a forming station (11) configured for this purpose. by forming without heat or by thermoforming in the lower material web (23) to form recesses (29) of the product areas (20), characterized in that the lower material web (23) comprises at least one layer (33) consisting of or comprising fibrous and / or plant-based raw material, and that at least one pretreatment device (55) is provided upstream of or at least partially integrated into the forming station (11), which is configured to subject the lower material web (23) to a pretreatment in which the moisture content of the material layer (33) is changed, in particular increased. Packaging machine according to claim 17, wherein the lower material web (23) is multilayered and comprises at least one upper layer (31) made of plastic and the lower layer comprising at least one material layer (33).Packaging machine according to claim 17 or 18, wherein the pretreatment device (55) is configured to apply treatment agents, in particular water, to the material layer (33), particularly in liquid form or in the form of vapor, mist, or aerosol. Packaging machine according to any one of claims 17 to 19, wherein the pretreatment device (55) is arranged on a supply roll (23a) formed by the wound-up lower material web (23), on the path of the lower material web (23) from the supply roll (23a) to the forming station (11), in particular immediately after the supply roll (23a), or at least partially in the forming station (11). Packaging machine according to any one of claims 17 to 20, wherein the pretreatment device (55) comprises a treatment container (57) containing the treatment agent in liquid form, or an at least partially enclosed treatment chamber containing the treatment agent in the form of vapor, mist, or aerosol, wherein the lower material web (23) is passable through the treatment container (57) or the treatment chamber. Packaging machine according to any one of claims 17 to 21, wherein the pretreatment device (55) comprises an application device (51) configured to apply the treatment agent to the material layer (33) by contact or without contact.Packaging machine according to claim 22, wherein the application device (51) is configured to dispense the treatment agent in the form of individual, flying quantities of liquid, to spray it in liquid form, or to emit it as vapor. Packaging machine according to claim 22 or 23, wherein the application device (51) is configured to dispense or emit the treatment agent in the direction of the underside of the material layer (33) forming the underside of the lower material web (23), and / or wherein the application device (51) has at least one dispensing opening (59) for the treatment agent, in particular wherein the dispensing opening (59) is formed by a nozzle (61). Packaging machine according to any one of claims 22 to 24, wherein the application device (51) is connected to a treatment agent reservoir (63), in particular wherein at least one container is provided for the treatment agent reservoir (63), which is attached to or located in the packaging machine. rail (V) arranged and in particular replaceable and / or refillable.

26. Packaging machine according to one of claims 22 to 25, wherein the application device (51) comprises a carrier (65) extending in a transverse direction, on which several dispensing openings (59), in particular several nozzles (61) each forming a dispensing opening (59), and supply lines (67) leading to the dispensing openings (59) for the treatment agent are attached.

27. Packaging machine according to one of claims 22 to 26, wherein the application device (51) has several dispensing openings (59) which can be controlled independently of each other.

28. Packaging machine according to one of claims 17 to 27, wherein the treatment means comprises several components, in particular separately stored components, which can be brought together before or at dispensing through a respective dispensing opening (59).

29. Packaging machine according to one of claims 17 to 28, wherein a control device (41) controlling the operation of the packaging machine (V) is provided, which is configured to control the pretreatment device (55) and / or the forming station (1 1 ) and / or to perform process control, in particular according to a method according to one of claims 1 to 16.

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