Flat embossing press with foil web guide and transport device

Abstract

The invention relates to a flat embossing press (1) for embossing a flat material (12), comprising a flatbed press (2) having a tool plate (4) and an embossing table (3), a foil web guiding and transporting device (7) for guiding at least one embossed foil web (6) along a foil transport path (17) onto the embossing table (3) of the flatbed press (2), a flat material guide (13) for guiding the flat material (12) through the flatbed press (2) along a flat material transport path (18), and a control device (80) for operating the flat embossing press (1). According to the invention, the foil web guiding and transporting device (7) behind the flatbed press (2) when considered in the transport direction (T1) of the flat material (12) comprises peeling elements (16) arranged above the flat material transport path (18) and behind the foil transport path (17) in order to hold back and peel off the embossed foil web (6) from the flat material (12) as the flat material (12) is transported away from the flatbed press (2).

Description

[Technical field]

[0001] The invention lies in the technical field of flat embossing presses and relates to a flat embossing press for embossing flat materials, comprising a foil web guiding and transport device for at least one embossing foil web which is guided onto an embossing table of a flat-bed press, as claimed in the preamble of claim 1. [Background technology]

[0002] Particularly high embossing output of the highest quality even for demanding embossing jobs can be carried out on a type of flat embossing press, also known as a flatbed embossing press.

[0003] For this reason, flat embossing presses impose particularly high demands on the guiding and precise advancement of the foils, on the one hand, on the thin, narrow and very delicate embossing foil webs, in particular holographic foil webs, and on the other hand, on the precise guiding and positioning of the flat material.

[0004] If a flat embossing press is equipped with a foil web guiding and transporting device for several embossed foil webs, under certain circumstances even several embossed foil webs of different types (with different web widths, advance lengths and different separation forces after embossing) need to be guided and transported simultaneously in a perfectly smooth manner.

[0005] The foil guidance must be performed in a perfectly planar, smooth, precisely positioned and especially in a register-accurate manner, without deformations, arches, folds and dislocations. The rapid and intermittent foil advancement of the embossed foil web needs to be carried out optimally gently so that a high output as well as a high quality can be achieved.

[0006] Such flat embossing presses with foil web guiding and transport devices are known, for example, from EP 1 593 503 A, WO 2009 / 143644 A, EP 0 858 888 A and EP 3 227 117 A.

[0007] In the case of demanding picture embossing operations, in particular hologram embossing with picture security features, e.g. for vouchers, identity cards or banknotes, with one or more embossing foil webs on a complete embossing table, not only must optimal and error-free positioning of the foil web and the flat material be achieved, but also a gentle and complete separation of the carrier foil web from the flat material, especially given the continued conveying after embossing.

[0008] The embossed foil web usually has a layer thickness of only 12-20 μm (0.012-0.02 mm). It generally comprises a carrier foil or carrier foil web, which consists of a plastic, for example polyester. The carrier foil web serves as the basis and transport medium for the other layers or picture elements, also called embossed pictures. The picture elements or embossed pictures to be transferred onto the flat material are deposited on the carrier foil web via a separating layer. The picture elements are characterized by optically effective properties. The picture elements can comprise or consist of metal and / or color layers. The picture elements can be in the form of security strips or patch strips, for example of securities, such as banknotes. The embossed foil web can thus be present as a foil strip. A typical width of the security strip is, for example, 8-12 mm. A typical width of the patch strip is, for example, 15-22 mm. In particular, the picture elements can be holograms.

[0009] The separating layer is a bonding and releasing layer, in particular of minimal thickness, which generally consists of a wax-like substance. On the one hand, it should hold the picture element on the carrier foil web, and on the other hand, this layer should allow the picture element to be released from the carrier foil web without damage after the embossing procedure. Generally, this is done by the separating layer melting or softening under the action of pressure and / or heat during embossing.

[0010] The carrier foil web, and thus also the picture element, is provided with an activatable adhesive layer on the embossed side. The activatable adhesive layer consists, for example, of a thermal adhesive or a radiation-curable plastic that is deposited over a large area. This layer is activated due to the thermal effect of the embossing tool (embossing stamp) or due to subsequent radiation and connects the picture element to be transferred to the flat material. The picture element transferred onto the flat material assumes a permanent adhesive connection with the flat material via the activated adhesive layer.

[0011] Radiation-cured adhesive layers in principle have a two-stage adhesive capacity. Thus, such adhesive layers develop a primary adhesion during the embossing procedure under the influence of heat. In a second stage, the adhesive layer after the embossing procedure is activated downstream of the flatbed press by suitable irradiation (e.g. UV radiation), which results in a permanent secondary adhesion by chemical reaction.

[0012] After the embossing procedure, the carrier foil web can be more or less released from the embossed picture elements depending on the design of the separation layer. With embossed foil webs with radiation-cured, especially UV-cured, adhesive layers, poor peeling behavior occurs.

[0013] The UV-cured adhesive layer of the embossed foil web being wound up on the unwinding roll therefore tends to adhere to the rear side of the carrier foil remote from the embossed surface, said carrier foil being adjacent on the unwinding roll, which requires that the adhesive properties of the separation layer between the carrier foil and the picture element be strengthened, so that when the embossed foil web is unwound from the unwinding roll, the picture element does not peel off from the carrier foil but remains adhered via the adhesive layer to the rear side of the adjacent carrier foil.

[0014] The release of the carrier foil web from the flat material in the case of a flat embossing press is usually performed by push separation, whereby the flat material is transported away from the flat bed press along a linear transport path, e.g. by a beam gripper, while the embossing foil web is guided obliquely upwards at an angle away from the flat material after the flat bed press and in the course of the foil advancement.

[0015] Vacuum means can be provided on the embossing table, so that when a push-through separation is applied the flat material or sheet is not lifted upwards by the still adhering embossing foil web, but said vacuum means holds the sheet on the embossing table by vacuum and only allows planar movement of the flat material away from the embossing table.

[0016] However, given the poor peeling behavior of the embossed foil web after the embossing procedure, this web remains adhered to the flat material longer than expected or desired. On the one hand, this causes the carrier foil web to be deformed, overstretched and damaged. On the other hand, the sheet is also thereby deformed, uneven and distorted, and instead of being transported planarly in the expected transport direction, it is deflected upwards by the adhered carrier foil web. Wrinkles may even form in the sheet. This results in a defective and unusable embossed product together with the subsequent cutting to size of the flat material. Summary of the Invention [Problem to be solved by the invention]

[0017] The object of the present invention is therefore to propose a modified embossing foil web guiding and transport device for a flat embossing printing machine, which allows an improved and reliable separation of the embossed foil web from the flat material after embossing, even if a separating layer with a greater adhesion effect is provided, and which ensures error-free guiding of the embossed foil web from the flat material after embossing, such that the flat material is not inadvertently deflected and deformed by the embossing foil web and that at least one of the foil webs is not overstretched and damaged. [Means for solving the problem]

[0018] According to the invention, this object is achieved by a flat embossing press comprising a foil web guiding and transporting device as claimed in independent claim 1 as well as by a method as claimed in independent claim 12.

[0019] The dependent claims relate to advantageous further developments of the invention with a foil web guiding and transport device and with the positioning of at least one embossed foil web as well as further improvements in the machine output and picture quality.

[0020] The flat embossing machine for embossing flat materials is a flatbed press comprising an embossing table and a tool plate; a foil web guiding and transporting device for guiding at least one embossed foil web along a foil transport path onto an embossing table of a flat-bed press; a flat material guide for guiding the flat material through the flatbed press along a flat material transport path; - a control device for operating the flat embossing press; Equipped with.

[0021] The invention is characterized in that the foil web guiding and transporting device behind the flatbed press, when considered in the transport direction of the flat material, comprises peeling elements arranged above the flat material transport path and behind the foil transport path in order to hold back and peel off the embossed foil web from the flat material as it is transported away from the flatbed press.

[0022] In particular, the embossed foil web is guided through a flatbed press above the flat material, and the stripping element is therefore positioned above the flat material transport path.

[0023] The flat material transport path represents the transport path followed by the flat material in the flat embossing press, whereas the foil transport path represents the transport path followed by the embossing foil web in the flat embossing press.

[0024] The foil web guiding and transporting device of the flat embossing press comprises in particular a foil feed device, further specified in more detail below, for feeding at least one embossed foil web to the flat bed press, and a foil pull-out device, also further specified in more detail below, for leading at least one embossed foil web away from the flat bed press. The foil web guiding and transporting device comprises in particular a foil advancement device, such as an advancement roller or an advancement roller pair, for carrying out the advancement of the foil on the flat bed press. In particular, the foil advancement device is arranged in the foil pull-out device.

[0025] An embossed foil web is to be understood as a foil or film which has at least one picture element or embossed picture to be embossed and which is led through a flatbed press. In particular, the embossed foil web is led through the flatbed press continuously, for example from roll to roll.

[0026] The at least one picture element or embossed picture can be a uniform or evenly shaped layer, for example a metal layer or a dye layer. The at least one picture element or embossed picture can cover the carrier foil completely or only partially.

[0027] The at least one picture element or embossed picture may also include a pattern or structure. These may be formed, for example, by different colors, materials or layer thicknesses. The at least one picture element or embossed picture is characterized, in particular, by optical effects resulting therefrom. In particular, the at least one picture element or embossed picture may be a hologram. In particular, the at least one picture element or embossed picture may be a security feature for securities, for example banknotes.

[0028] The embossed foil web in particular comprises several picture elements or embossed pictures. Such an embossed foil web is also called a picture foil web. The picture elements or embossed pictures can completely cover the carrier foil. In this case, the picture elements or embossed pictures are adjacent to one another. The picture elements or embossed pictures can also only partially cover the carrier foil. In this case, the embossed foil also forms areas that are not covered by the picture elements or embossed pictures. Here, for example, the picture elements or embossed pictures can be arranged on the carrier foil at a distance from one another.

[0029] As a rule, the embossed foil web exists as a roll product and is guided and transported from an unwinding roll as part of the foil feed device, through the flatbed press, to a take-up roll as part of the foil withdrawal device of the flat embossing press.

[0030] For simplicity, in this disclosure, the term embossed foil web is used consistently for the foil web before embossing of picture elements and for the foil web after embossing of picture elements, which also takes into account the fact that for a given embossing pass, not all pictures of the embossed foil web are necessarily embossed.

[0031] The flat embossing press can be designed in particular for the simultaneous embossing of one or more embossing foil webs, which are guided on the embossing table parallel to one another on a flat material. In the course of the description of the invention, for the sake of simplicity, reference is made in each case to one embossing foil web. However, this does not exclude the simultaneous processing of several embossing foil webs on a flat material. The features of the device and the features of the method according to the invention can therefore also be applied to further embossing foil webs on the same flat embossing press.

[0032] In particular, the flat material is paper or cardboard. The flat material can be present as sheets that are individually transported into the flatbed press, embossed with the picture element, and transported away from the flatbed press again. The transport of the sheets can be via a gripper, such as a gripper beam, which grips the sheet by its leading edge and pulls the sheet through the flatbed press along a sheet transport path in the transport direction.

[0033] The sheets can be withdrawn from the sheet stack individually in a sheet feeder. After the embossing procedure, the embossed sheets can be deposited on the sheet stack in the sheet delivery section.

[0034] However, it is also conceivable that the flat material exists as a web that is continuously guided through the flatbed press, in which case the flat material can exist as a rolled product and can be transported from an unwind roll to a take-up roll via the flatbed press.

[0035] Flatbed presses are characterized by the design of a flat or planar embossing area. In a flatbed press, the tool plate and the embossing table are designed flat, so they are also called flat-flat presses.

[0036] The flat material transport path extends in particular straight and more particularly horizontally in a path section which connects directly to the flatbed press and extends to the peeling element.

[0037] The flat material transport path extends in particular linearly, more in particular horizontally, beneath the stripping element. The foil transport path has a path component that runs vertically away from the flat material transport path, in particular upwards, in the transport direction after the flatbed press. This means that the transport paths of the flat material and the embossed foil web that run adjacent and parallel to one another in the flatbed press run diverging at the outlet of the flatbed press. The foil transport path runs obliquely upwards in the transport direction in particular after the flatbed press.

[0038] Here, the peeling element is positioned relative to the flat material transport path, in particular at a distance from the flat material transport path, so that the embossed foil web adhering to the embossed flat material transported away from the flatbed press and through the peeling element below is held back by the peeling element and thus peeled off.

[0039] According to a particular further development of the invention, the peeling element is arranged at a particular distance relative to the flat material transport path or the flat material in such a way that the embossed foil web adhering to the embossed flat material is peeled off from the flat material during the formation of an open foil loop, hereinafter referred to as a peeling loop, coming from the peeling element and extending downstream in the transport direction of the flat material.

[0040] In this case, the peeling elements also serve to form an open peel loop, for which an acute peel angle is created between the embossed foil web, considered in the conveying direction, peeled off behind the peel point and the embossed foil web, which adheres to the flat material in front of the peel point, which has a positive effect on the peeling procedure.

[0041] The acute peel angle is, for example, less than 90° (degrees), in particular less than 75°, in particular less than 60°, more particularly less than 45°. Furthermore, the acute peel angle is, for example, greater than 0°, in particular greater than 5°, in particular greater than 10°, more particularly greater than 15°.

[0042] According to a further development of the flat embossing press, in order to deflect the embossing foil web from the conveying direction of the flat material, the foil web guiding and transporting device comprises a deflecting element which is arranged above the flat material conveying path and before the peeling element at the outlet of the flatbed press, considered in the conveying direction of the flat material, so that the embossing foil web is guided between the deflecting element and the peeling element.

[0043] The stripping element is therefore arranged after the deflection element in the conveying direction of the flat material. As a result, the deflection element is arranged on the same side of the flat material as the stripping element, in particular above the flat material.

[0044] The deflection element forms a deflection surface, in particular an arcuate one, for deflecting the embossed foil web from the conveying direction of the flat material. The deflection element can be a longitudinal component, such as a rod, extending perpendicular to the conveying direction of the embossed foil web. In particular, the deflection surface of the deflection element is stationary, so that the peeled off embossed foil web is guided onto the deflection surface.

[0045] In particular, the deflection element is arranged at a distance to the flat material transport path or to the flat material. According to a further development of the invention, the stripping element is arranged at a distance relative to the flat material transport path or to the flat material.

[0046] The distance of the deflection element to the flat material transport path or to the flat material is in particular greater than the distance of the stripping element to the flat material transport path or to the flat material.

[0047] The peeling elements can for example be arranged at a distance of 1 mm or more, in particular 2 mm or more, more in particular 3 mm or more to the flat material transport path or to the flat material.

[0048] The peeling elements may furthermore for example be arranged at a distance of 30 mm or less, in particular 20 mm or less, more in particular 10 mm or less to the flat material transport path or to the flat material.

[0049] In particular, the stripping element forms an arcuate deflection surface for deflecting the embossed foil web from the transport direction of the flat material.

[0050] The peeling element may be a longitudinal component, such as a rod, extending transversely to the conveying direction of the embossed foil web. The deflection surface of the peeling element may be stationary, so that the peeled embossed foil web is guided onto the deflection surface.

[0051] The peeling element can also be a rotatable roller, the side of which thus forms a rotatable deflection surface for the peeled embossed foil web. The roller can be actively driven or freely rotatable.

[0052] According to a further development of the invention, the flat embossing press or the foil feed device comprises an unwinding device for unwinding the embossing foil web from an unwinding roll.

[0053] According to a further development of the invention, the flat embossing press or foil feed device comprises a foil storage section arranged before the flatbed press, in particular between the unwinding device and the flatbed press, for temporary intermediate storage of a foil web length of the embossed foil web between two embossing procedures.

[0054] The foil store comprises in particular a store-forming device for filling a receiving space of the foil store with an embossed foil web length.

[0055] In particular, the foil storage section is designed for intermediate storage of foil web excess lengths therein, said foil web excess lengths being advanced or fed through the flatbed press beyond a predefined advance length and being pulled back again against the advance direction by the foil feeding device, if the respective foil web excess length does not need to be rewound onto the unwinding roll.

[0056] Furthermore, in particular the foil store is designed for intermediate storage of a foil web length for a subsequent foil advance.

[0057] Flat embossing presses have very short press cycles and therefore high cycle speeds, which can carry out, for example, 50 embossings per minute. This requires a high foil advance speed. The advance length of the embossed foil web must therefore be provided in a short time. Since the unwinding of the embossed foil web from the unwind roll is a relatively slow procedure, advantageously a foil store is provided between the unwind roll and the flatbed press, which has a short reaction time for the release of the intermediately stored embossed foil web length. The intermediately arranged foil store allows a slower, in particular continuous, unwinding of the embossed foil web from the unwind roll, said unwinding being not directly coupled to the foil advance. The wound up embossed foil web is stored intermediately in the foil store until its recovery.

[0058] Thus, the advance length of the embossed foil web for the foil advance is taken from the foil store.

[0059] In particular, the foil store is a foil loop store in which a foil web length in the form of at least one open foil loop is stored intermediately in a loop receiver.

[0060] The depository forming device is in particular a pressure differential device for drawing the embossed foil web length into the foil depository, in particular for forming open foil loops, by means of an air pressure difference acting on the foil web. The air pressure difference can be generated, for example by a pressurized air device, for example by exposing the embossed foil web to an air flow. The air pressure difference can also be generated by applying a vacuum to the foil web, for example by a vacuum device. A combination of the two aforementioned methods is also possible.

[0061] If an air pressure difference is created by applying a vacuum, the loop receiver can be a suction channel in which a suction draft is applied, which draws in the embossed foil web led past the channel openings. Such a foil loop store is described, for example, in EP 0 858 888 A1.

[0062] The invention further relates to a method for operating the flat embossing press according to the invention as further explained above, in particular for peeling the embossing foil web from the embossed flat material after the embossing procedure.

[0063] To perform the embossing procedure, the embossed foil web by the foil advance and the flat material are transported and positioned in an open flat-bed press on an embossing table. The embossed foil web and the flat material are then brought together by closing the flat-bed press, a tool plate with a heated embossing tool is pressed against the embossing table, and the embossing procedure is performed by the action of pressure and heat, in which the picture elements are transferred from the embossed foil web to the flat material.

[0064] After completion of the embossing procedure, the flatbed press is opened and the embossed flat material together with the embossed embossed foil web section is transported away from the flatbed press while the advance length of the picture path foil is fed by the foil advance. The embossed foil web section transported away from the flatbed press together with the flat material is detached from the flat material at the exit of the flatbed press and is transported further in a separate manner.

[0065] The advance length of the foil advance corresponds to the embossing section of the flatbed press including the dummy section in which e.g. printed marks for accurate positioning of the registration of the embossed foil web can be placed on the flatbed press. A typical advance length can be e.g. 700 mm.

[0066] The control device is designed in principle such that the foil pull-out device executes a foil advance with a defined advance length in each embossing cycle. The foil advance moves in particular according to a predefined speed profile stored in the control device. The foil feed device here provides the advance length required for the foil advance, for example at the intermediate foil store.

[0067] For a given foil advance, it is ensured on the one hand that the correct embossed foil web section with the picture elements is fed to the flatbed press, and on the other hand that an excessively large or excessively long foil web is not fed, in order to avoid unnecessary consumption of foil, on which the picture elements cannot be embossed.

[0068] The release of the embossed embossing foil web section from the flat material at the outlet of the flat bed press is achieved by directing the embossing foil web into a deflection section.

[0069] The method according to the invention is characterized in that after the embossing procedure, the flat material is transported away from the open flat-bed press along the flat material transport path through a peeling element, and the co-transported embossing foil web hits the peeling element activating the peeling of the embossing foil web from the flat material.

[0070] In particular, flat material is conveyed through it below the stripping element. The peeling element serves in particular to hold back the embossed foil web adhering to the flat material, which means that the peeling element holds back the embossed foil web adhering to the flat material from further transport in the transport direction of the flat material.

[0071] According to a further development of the method, the embossed foil web adhering to the flat material is peeled off from the flat material during the formation of an open peel loop which comes from the peeling element and extends or is formed downstream in the conveying direction of the flat material.

[0072] This results in one limb of the peel loop being formed by the embossed foil web section adhering to the flat material.

[0073] This allows the peeling loop to reach loop lengths of up to 50 mm, in particular up to 100 mm.

[0074] The formation of the peel loop or the loop length of the peel loop is controlled, inter alia, by the speed course or speed profile of the foil advance.

[0075] Thus, after completion of the embossing procedure and after opening of the flatbed press, the foil advance is delayed, especially with respect to the discharge of the flat material from the flatbed press, which means that the foil advance does not start until a certain amount of the embossed flat material has already been withdrawn from the flatbed press.

[0076] This allows the embossed flat material with the embossed foil web adhering thereto to be advanced towards or beyond the peel element without the leading free embossing foil being immediately (later) pulled along by the foil advance, specifically the latter inhibiting or preventing the formation of peel loops.

[0077] The greater the delay in foil advance, the larger the peel loop that is formed. During the peeling procedure, the loop length can be influenced or controlled by the speed course or speed profile of the foil advance. An increase in the speed of the foil advance relative to the sheet transport results in a reduction in the size of the peeled loop. A decrease in the speed of the foil advance relative to the sheet transport results in an enlargement of the peeled loop.

[0078] Since the speed profile of the sheet transport cannot in principle be changed, an increase or decrease in the relative speed is brought about in particular by a change in the foil advance speed.

[0079] According to a particular embodiment of the method, the foil advance and the sheet transport have the same speed during the peeling procedure, so that the loop size or length remains constant during the peeling procedure.

[0080] However, an increase in the foil advance speed relative to the sheet transport can be envisaged near the end of the peeling procedure in order to reduce or eliminate the peel loops. The embossed foil web excess length is also reduced in size due to the reduction in size, or even elimination, of the peel loops towards the end of the peeling procedure.

[0081] For process-related reasons, it is indeed desirable that the embossing foil web excess length that is pulled back is as short as possible. On the one hand, this is in order to fill the foil store with the embossing foil web excess length as short as possible. On the other hand, if possible, the embossing cycle is not lengthened by the extended pullback of the embossing foil web excess length. Furthermore, the less the embossing picture foil excess length that has to be pulled back, the faster and more accurate is the correct positioning of the registration of the embossing picture foil when reading the printing marks.

[0082] For this reason, in a further development of the method it is envisaged that the speed of foil advancement is increased relative to the conveying speed of the flat material towards the end of the peeling procedure so that peeling loops are reduced and in particular removed at the end of the peeling procedure.

[0083] The loop length or loop shape may further change during the peel procedure due to changes in the peel force at the peel point or line.

[0084] This means that the release or peeling procedure of the embossed foil web from the flat material is not necessarily uniform. The peeling force may therefore vary within the release procedure. This is the case, for example, when the carrier foil is not provided with picture elements continuously in the transport direction. This means that the embossed foil web does not adhere to the flat material in the areas between two consecutive picture elements or embossed pictures, or adheres only to a limited extent. Due to the absence or reduction of the peeling force between the picture elements or embossed pictures, the peeling points in these surface areas bounce back against the transport direction, leading to a reduction in the tension of the already peeled embossed foil web after the peeling point. The reduction in tension can lead to an increase in the peel angle and a reduction in the loop length as well as deformation and therefore a change in the shape of the peeled loop due to a rapid reduction in the foil tension.

[0085] If the embossed foil web is provided with picture elements or embossed pictures continuously in the transport direction, a uniform peeling force can be assumed, so that the loop tension remains constant. The loop length during the peeling procedure is influenced solely by the above-mentioned speed difference between the foil advance and the transport speed of the flat material.

[0086] When processing an embossed foil web, whose carrier foil web can be separated from the flat material in a relatively easy manner after the embossing procedure, the releasing procedure as a rule takes place directly at the exit of the flatbed press under the deflecting elements of the foil web guiding and transporting device. The embossed foil web is thus released from the flat material by push separation.

[0087] For an embossed foil web with worse peel behavior, the flat material with the adhered embossed foil web, in contrast, moves downstream from the flat bed press towards the peeling element and further downstream beyond the peeling element during the formation of an open peel loop.

[0088] Downstream movement of the flat material having the picture foil web adhered thereto requires feeding the embossing foil web through the flatbed press in an advance direction, such feeding exceeding the advance length for a given foil advance.

[0089] The fed excess length of the embossed foil web corresponds approximately to the distance between the peeling point of the embossed foil web just before its release from the flat material at the trailing edge of the embossed flat material or the trailing edge of the embossing sheet and the exit end of the embossing area of ​​the flat bed press (the dummy portion that occurs is not included in the calculation).

[0090] According to a further development of the method, the embossing foil web excess length advancing through the flatbed press is pulled back again after the peeling procedure in the opposite direction to the foil advance direction. A predetermined foil tension is also generated again in the flatbed press by pulling back the embossing foil web excess length. In some cases, it is also ensured in this way that the embossing foil web is positioned in register with respect to the flat material in the flatbed press for the subsequent embossing procedure.

[0091] Since the foil guiding and transporting device cannot pull back the length of the embossed foil web from the foil advancing device, the embossed foil web as described above can simply be pulled back until a defined foil tension is reached, so for this method step it is not necessary to know the embossed foil web excess length.

[0092] The retracted embossing foil web excess length is in particular stored intermediately in a foil storage section for a later embossing procedure, which means that the retracted embossing foil web excess length becomes part of the intermediately stored embossing foil web length for a later foil advancement.

[0093] In order to provide a suitable length of embossed foil web to be stored intermediately in the foil storage section, for the subsequent advancement of the foil, in particular a further length of embossed foil web is unwound from the unwinding roll and, together with the retracted excess length of embossed foil web, is stored intermediately in the foil storage section, in particular a foil loop.

[0094] The guiding of the embossed foil web through the flatbed press is therefore carried out over several embossing cycles in the manner of a Pilger process, by the embossed foil web being advanced over the embossing table by the advance length + foil web excess length after an embossing step, then being pulled back again by the foil web excess length, after which the next embossing step is advanced over the embossing table by the advance length + foil web excess length again, and so on.

[0095] In particular, the embossed foil web excess length is pulled back by a storage-forming device of the foil storage. The storage-forming device here exerts a tensile force on the embossed foil web against the advancement direction during the peeling procedure. The tensile force ensures the maintenance of the foil tension, but simultaneously allows foil advancement as well as (later) pulling of the foil web excess length. As a result, the tensile force applied against the advancement direction is smaller than the tensile force applied to the embossed foil web during foil advancement. In particular, this also relates to the tensile force applied to pull back the embossed foil web excess length.

[0096] According to a further development of the method, as soon as the embossed foil web is completely released from the flat material, the highly embossed foil web excess length that is not (later) pulled by the foil advancement device bounces back due to the tensile force. This is the case when the peeling point reaches the rear end of the embossed flat material or the rear end of the sheet and is peeled off from the flat material. In particular, the rebound of the embossed foil web can be performed in the manner of a whipping movement.

[0097] When the picture elements of the embossed foil web are deposited positionally accurately or in register on the flat material, the printed marks detected by the printed mark sensor can be deposited on the embossed foil web. The foil advance can be performed positionally accurately or in register with the flat material by the control device based on the printed marks detected by the printed mark sensor.

[0098] A constant foil tension is necessary for the registration of the embossed foil web, which is therefore achieved especially in the embossed foil web section where the foil tension can be controlled or adjusted.

[0099] Thus, a brake-and-guide wall can be arranged between the foil store and the flatbed press, through which the embossed foil web passes and which serves as a foil tensioning device for tensioning the embossed foil web in the open flatbed press. Such a brake-and-guide wall is explained in more detail below in the context of an example embodiment according to Fig. 1. A detailed description of the brake-and-guide wall can also be found in the published document EP 1 593 503 A1.

[0100] Additionally or alternatively, a brake-guide wall may be arranged between the peeling element or the deflection rod and the foil advancing device, which allows control of the foil tension between the brake-guide wall and the foil advancing device. The structure of the brake-guide wall may be as described above.

[0101] In order to register the embossed foil web, in particular a print mark sensor for detecting and reading the print marks on the embossed foil web is arranged along the foil transport path. In particular, the print mark sensor is arranged in the embossed foil web section, in which the foil tension can be controlled or adjusted. This applies in particular after the braking and guiding wall. Possible positions of the print mark sensor are disclosed, for example, in the context of the embodiment example according to FIG. 1.

[0102] The device and the associated method according to the invention allow the embossed foil web to be reliably, malfunction-free and damage-free detached from the flat material, even when a highly adhesive separating layer is applied. The formation of the peel loop results in a change in the main directional component of the peel force acting on the flat material from perpendicular to parallel to the flat material, so that even when a larger detachment force is applied, the flat material is loaded to a lesser extent and no deformation or other damage to the flat material occurs.

[0103] Furthermore, the peeling elements also contribute to preventing the flat material from being deflected transversely to the transport path during the peeling procedure in the direction of the directly peeled embossed foil web.

[0104] A further aspect of the invention relates to the control of the foil tension of the embossed foil web section that is led through the flatbed press. In order to avoid the formation of folds and therefore embossing defects, it is necessary to apply pretension to the embossed foil web section that is led through the flatbed press before the embossing step. By applying a predetermined or specified foil tension with each embossing step, it is further possible to transfer the embossed picture onto the flat material in a controlled or precise registration. The embossed foil thus has a certain stretch or elasticity, whereby the application of the foil tension results in the stretching of the foil and therefore also in the displacement of the embossed pictures relative to each other.

[0105] For this reason, the stretching of the foil when applying pretension or tension to the embossed foil web section must also be taken into account for the accurate transfer of the embossed picture in registration onto the flat material. This means that, given a defined foil tension or stretch of the embossed foil, the embossed picture is placed on the embossing foil so that it is transferred in registration onto the flat material. The stretching of the foil in this specification depends not only on the tension applied to the embossed foil web, but also on the stretchability and temperature sensitivity of the applied embossing foil or its carrier foil. These variables must also be taken into account when determining the foil stretching.

[0106] Therefore, when setting up a flat embossing press, the foil tension of the embossing foil web section must be set so that the embossed picture of the embossing foil web section that is led through the flat bed press is in register with the underlying flat material. Now, after setting up the flat embossing press for a production lot, it is important that the same foil tension is applied throughout all embossing cycles. Only in this way will the embossed picture be transferred onto the flat material in a register-accurate manner at each embossing cycle.

[0107] If another embossing foil with other characteristics is applied in a subsequent production lot, the foil tension will need to be set anew during the flat embossing press setup.

[0108] As already mentioned further above, when considered in the conveying direction of the embossed foil web, a braking and guiding wall with a guide surface for the embossed foil web can be arranged in front of the flatbed press as part of a foil tensioning device, onto whose guide surface the embossed foil web is guided and serves to tension the embossed foil web in the open flatbed press. The guide surface can interact with a vacuum device, whereby a vacuum can be generated at the guide surface. The applied vacuum ensures the support or suction of the embossed foil web onto the guide surface of the braking and guiding wall. The applied vacuum also ensures, in particular, the braking of the embossed foil web. The greater the applied vacuum, the greater the braking effect on the embossed foil web and the higher the foil tension of the embossed foil web section guided through the flatbed press and vice versa.

[0109] As also described in detail above, the rebound of the embossed foil web against its transport direction occurs after the embossing procedure and after the complete release of the embossed foil web from the embossed flat material, and therefore must be pulled back by a defined amount relative to the transport direction of the embossed foil web in order to generate the foil tension again.

[0110] This is achieved, for example, by a foil store arranged in front of the brake-guide wall in the conveying direction, as mentioned above. However, for example pulling back the embossed foil web into the foil store is only possible if the brake-guide wall does not exert a braking effect and, as a consequence, no vacuum or suction force on the embossed foil web. As a consequence, the brake-guide wall has to be ventilated in order to pull back the embossed foil web. The brake-guide wall is therefore supplied with a vacuum and evacuated alternately over several embossing cycles. The brake-guide wall acts limitingly in shortening the embossing cycles, since the change between vacuum supply and ventilation cannot be achieved infinitely quickly for technical reasons.

[0111] It is therefore an object of this further aspect of the invention to advance a foil tensioning device for controlling the tension of an embossing foil web section guided through a flatbed press instead of or complementary to a brake and guide wall, said device allowing a further shortening of the embossing cycle.

[0112] A flat embossing press for embossing a flat material according to this aspect of the invention comprises: a flatbed press comprising a tool plate and an embossing table; a foil web guiding and transporting device for guiding at least one embossed foil web along a foil transport path onto an embossing table of a flat-bed press; a flat material guide for guiding the flat material through the flatbed press along a flat material transport path; a foil tensioning device for tensioning the embossed foil web section guided through the flatbed press; - a control device for operating the flat embossing press; Equipped with.

[0113] A foil tensioning device according to a second aspect of the present invention comprises: a foil clamping device for clamping the embossing foil web at a clamping position arranged in front of the flatbed press in the conveying direction of the embossing foil web; a foil deflection device for deflecting at least one embossed foil web from the foil transport path after a clamping position considered in the transport direction of the embossed foil web in order to control the foil tension; Equipped with.

[0114] In particular, foil tensioning devices are designed to temporarily deflect the embossing foil web during an embossing cycle or procedure for the purpose of controlling the foil tension.

[0115] In particular, the foil deflection device is designed to deflect at least one embossed foil web from the foil transport path between a clamping position and the flatbed press.

[0116] According to a further development, the above-mentioned foil clamping device is a first foil clamping device and the clamping position is a first clamping position. The foil tensioning device further comprises a second foil clamping device for clamping the at least one embossed foil web at a second clamping position, which is arranged after the flatbed press in the conveying direction of the at least one embossed foil web. The foil deflecting device is here designed to deflect the at least one embossed foil web from the foil conveying path between the first and the second clamping positions.

[0117] The foil tensioning device is in particular part of or assigned to a foil web guiding and transporting device. The (first) foil clamping device and the foil deflecting device are in particular part of or assigned to a foil feed device.

[0118] If present, the second foil clamping device is in particular part of or assigned to the foil extraction device.

[0119] The (first) clamping position and in particular the foil deflection device are arranged in the press run-in. The (first) clamping position and in particular the foil deflection device are arranged just before the flatbed press.

[0120] The second clamping position, if present, is in particular located within the press runout or after the stripping element, if present. In particular, the second clamping position is located immediately after the flatbed press or immediately after the stripping element, if present.

[0121] By clamping positions or placement of clamping positions directly adjacent to the press entrance or press exit, the tensioned embossing foil section is kept as small as possible, thereby allowing more accurate positioning of the embossing foil or its embossed picture within the flatbed press.

[0122] The term "clamped" means in particular that the embossing foil is held by a clamping device, i.e. it cannot be moved or pulled through the clamping position. The clamp can be two-dimensional or linear. The embossing foil web is in particular clamped over its entire width by the foil clamping device.

[0123] In particular, the foil clamping device is designed to assume a clamping position in which the embossing foil web is clamped and a transport position in which the embossing foil web can move through the foil clamping device.

[0124] In particular, the foil clamping device according to the claims is characterized in that it comprises a clamping element on each of both sides of the embossing foil web, between which the embossing foil web can be clamped.

[0125] At least one clamping element of the foil clamping device is designed to assume a clamping position in which the embossed foil web is clamped and a conveying position in which the embossed foil web can be moved in the conveying direction through the foil clamping device. For this purpose, the clamping element is in particular movably mounted.

[0126] Thus, the at least one clamping element can for example be a clamping roller which in the clamping position is blocked, ie does not rotate, and in the conveying position is rotatable, in particular freely rotatable.

[0127] According to a further development of the at least one clamping element, it is movable, in particular pivotable, with a movement component transverse to the foil transport path towards the embossed foil web in order to clamp the embossed foil web, i.e. to assume the clamping position. The clamping element is movable, in particular pivotable, with a movement component transverse to the foil transport path away from the embossed foil web in order to release the clamp, i.e. to assume the transport position. The movement away is in particular a movement opposite to the movement towards. Here too, the movable clamping element can be, for example, a clamping roller.

[0128] The movable or movably mounted clamping elements are driven or moved via a drive, in particular an electric motor or a pneumatic or hydraulic drive, which is controlled via a control device.

[0129] The clamping element can also be stationary, i.e. cannot be displaced and in particular cannot move. Such a clamping element can be formed, for example, by a brake-guide wall. However, it is also conceivable not to provide a brake-guide wall, since the essential function of the brake-guide wall, in particular the tensioning of the embossed foil web, is envisaged by the foil tensioning device according to the invention.

[0130] The clamping elements can therefore also be formed by fixed, i.e. non-displaceable, in particular immovable, guide elements such as guide rollers or guide rods.

[0131] However, it is also conceivable for both clamping elements to be mounted movably, i.e. displaceably.

[0132] In the context of this aspect of the invention, transverse to the foil transport path means in particular parallel to the surface normal of the embossed foil web.

[0133] According to a further development of the invention, a foil deflection device for deflecting the embossing foil web is arranged before the flatbed press considered in the transport direction of the embossing foil web.

[0134] The foil deflection device is in particular arranged between a foil store, such as a foil loop store, and the flatbed press. The foil store serves in particular for temporary intermediate storage of foil web lengths of the embossed foil web between two embossing procedures.

[0135] The foil deflection device comprises a foil deflection element which is movable, in particular pivotable, with a movement component transverse to the foil transport path, in particular for the purpose of deflecting the embossed foil web. The foil deflection element can thus be pivotally mounted via a pivot axis. The foil deflection element can for example be part of a lever mechanism. The foil deflection element can also be movable with a movement component transverse to the foil transport path via a linear movement. The foil deflection element is driven or moved in particular via a drive, such as an electric motor or a pneumatic or hydraulic drive. The drive is controlled via a control device.

[0136] To deflect the embossed foil web, the foil deflection element is moved towards the embossed foil web with a movement component transverse to the foil transport path. The foil deflection element here presses the embossed foil web laterally, i.e. transversely to the foil transport path. The embossed foil web that is pushed away laterally forms, in particular, laterally protruding arched or open foil loops.

[0137] Due to the deflection of the embossed foil web, the foil path or transport stretch of the embossed foil web becomes longer, in particular between the counterholder elements described below.

[0138] Considered in the conveying direction, the embossing foil web is clamped before and after the embossing foil deflection device, so that the additional path stretching for the transverse deflection can only be provided by tensioning or stretching the embossing foil web section guided through the flatbed press. The tensioning or stretching of the embossing foil web section can be set in a relatively simple manner depending on the degree of deflection of the embossing foil web. Thus, for example, it is conceivable to stretch the foil by 4 mm to 10 mm per meter of travel.

[0139] According to a further development of the invention, the foil deflection device comprises two counterholder elements which are spaced apart from each other along the transport direction of the embossed foil web and arranged on the side of the embossed foil web opposite the foil deflection element, a deflection section of the embossed foil web being formed between the counterholder elements.

[0140] The counterholder elements ensure that the embossing foil web is only deflected between the counterholder elements. The foil deflection element therefore acts to deflect the embossing foil web between the two counterholder elements, i.e. moves towards the embossing foil web between the two counterholder elements. When deflecting the embossing foil web, this is deflected accordingly into deflection around the counterholder elements.

[0141] The counterholder element can be a guide element such as a guide rod or a guide roller. In particular, the counterholder element is arranged stationary.

[0142] If several embossing foil webs are led through the flatbed press adjacent to one another, in particular parallel to one another, considered in the foil transport direction, a foil deflection device is in particular assigned to each embossing foil web, which allows an individual setting or control of the foil tension for each embossing foil web.

[0143] In a further development of this variant, it is also conceivable to assign a foil clamping device or a first and a second foil clamping device to each embossed foil web, which allows individual clamping of the embossed foil webs. However, the embossed foil webs can also be clamped by a common foil clamping device or a first and a second foil clamping device.

[0144] A corresponding method for operating the aforementioned flat embossing press also belongs to a further aspect of the invention. For this, the embossing foil web and the flat material are positioned in a flat bed press and brought together by closing the flat bed press. An embossed picture is transferred from the embossing foil web onto the flat material by an embossing procedure.

[0145] A further aspect of the invention is characterized in that, before closing the flatbed press, the embossed foil web is clamped in a clamping position or in a first and a second clamping position, after which the foil deflection element is moved, in particular pivoted, towards the embossed foil web, which foil deflection element deflects the embossed foil web transversely to the foil transport path until the embossed foil web section guided through the flatbed press has a predetermined tension.

[0146] The foil tensioning device according to the invention, as described above, allows for the control or setting of the foil tension and thus a controlled stretching of the foil before each embossing cycle.

[0147] Furthermore, the foil tensioning device according to the invention is also characterized in that it allows a relatively quick change between the clamping position and the conveying position. In particular, this is important in the case of flat embossing presses with peeling elements according to the first aspect of the invention. The clamping device must therefore be in the clamping position during the embossing cycle for the correct registration positioning of the embossing foil web and must change to the conveying position after the embossing procedure in order to pull back the foil web excess length and the subsequent feed or advance of the embossing foil web. This means that the clamping device changes constantly between the clamping position and the conveying position over several embossing cycles. The faster this change between the clamping position and the conveying position, the shorter the duration of the embossing cycle. A quicker change between the clamping position and the conveying position and therefore a shorter cycle time compared to a brake-guide wall is achieved by the foil tensioning device according to the invention.

[0148] The subject matter of the invention is explained in more detail below by means of example embodiments which are represented in the accompanying drawings, in which, diagrammatically in each case, are: [Brief description of the drawings]

[0149] [Figure 1] FIG. 2 is a cross-sectional view of a flat embossing press according to the present invention. [Diagram 2] 2 is a cross-sectional view from the area of ​​the peeling element of the flat embossing press according to FIG. 1. [Diagram 3] FIG. 2 is a cross-sectional view of a typical embossing foil. [Figure 4] 4 is a velocity profile of the foil advance and sheet transport. [Diagram 5] FIG. 13 is a cross-sectional view of a further embodiment of a flat embossing press from the area of ​​the flatbed press. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0150] Essentially, the same parts in the figures are provided with the same reference numbers. Certain features, for example features that are not essential to the invention, are not depicted in the drawings in order to allow a better understanding of the invention. The described embodiment examples are illustrative or serve to explain the subject matter of the invention and do not have a limiting effect.

[0151] 1 shows an example of an embodiment of a flat embossing press 1 according to the invention, with a flatbed press 2 designed as a flat-flat press for embossing sheets 12. The flatbed press 2 comprises an embossing table 3 with a counter pressure plate and a tool plate 4 (not shown) with a heated embossing tool, also called a "cliché", as a counter piece, which is arranged on this tool plate with the embossing side.

[0152] The sheets 12 to be embossed are individually pulled off from a sheet stack 63 provided in a sheet feeder 60 and transported via a transport device 61 to the flat embossing table 3. For this, the isolated sheets 12 are gripped and held at their leading edge by a gripper beam 62, whereby they are pulled onto the embossing table 3 of the open flat-bed press 2 and positioned below the embossing foil web 6.

[0153] The embossed foil web 6 is constructed in multiple layers and comprises a carrier foil 55, for example of polyester, which serves as a carrier for the further layers (see FIG. 3). An embossed picture 57 is arranged on the carrier foil 55 via a separating layer 56. An outer activatable adhesive layer 58 is arranged on the embossed picture 57 on the embossed side of the embossed foil web 6.

[0154] During the embossing procedure, the embossed picture 57, which previously has an adhesive layer, is pressed against the sheet 12. By activating the adhesive layer 58, for example by heat, the embossed picture 57 connects to the sheet 12 via the adhesive layer 58. Meanwhile, the separating layer 56 loses or is reduced in its adhesive strength under the influence of heat, so that the carrier foil 55 can be released from the embossed picture 57 along the separating layer 56 after the embossing procedure and said embossed picture is applied onto the sheet 12.

[0155] Each embossed sheet 12 after the embossing procedure is pulled from the open flatbed press 2 by gripper bar 62 and fed to sheet delivery section 70 during the formation of a sheet stack 73 of embossed sheets.

[0156] The flat embossing printing press 1 further comprises a foil web guiding and transporting device 7 for transporting and guiding an embossing foil web 6, also called picture foil web, on which an embossed picture 57 is arranged, through the flatbed press 2.

[0157] The foil web guiding and transport device 7 comprises a foil feed device 20 for feeding the embossed foil web 6 to the flatbed press 2. The foil feed device 20 comprises an unwinding device 21 for receiving an unwinding roll 22, on which the embossed foil web 6 is wound as a roll product, from which the embossed foil web 6 is unwound for foil advancement.

[0158] The flat embossing press 1 or the foil web guiding and transport device 7 comprises a foil loop storage 23 downstream of the unwinding device 21 and in front of the flatbed press 2 in the transport direction T2 of the embossed foil web 6. The foil loop storage 23 comprises at least one loop receiving portion 25 for receiving the foil loops 11 and a vacuum device 24 for forming the foil loops 11 in the loop receiving portion 25. For this purpose, a vacuum is applied by the vacuum device 24 to the embossed foil web 6 which is led through the loop receiving portion 25. The embossed foil web 6 is thereby sucked into the loop receiving portion 25 during the formation of the foil loops 11.

[0159] Furthermore, as already avoided above, the foil advance on the flatbed press 2 is intermittent, this foil advance coinciding with the embossing cycle. Thus, for example, the embossing foil web 2 is stationary in the closed flatbed press 2 during the embossing procedure, but given an open press, the foil advance is made at high speed at the beginning of a new embossing cycle. The foil advance must be made in as gentle and precise a manner as possible, and even in a rapid manner, so that on the one hand the embossing foil web 6 advances quickly, but nevertheless advances gently to the next embossing position and is positioned in a precise manner, or even in a register on the embossing table 3, and is still maintained in a positionally precise manner when closing the flatbed press 2.

[0160] When changing between holding still and foil advancing, or between foil advancing and holding still, the velocity profile covered has large positive or negative accelerations.

[0161] Since the unwinding device 21 with the heavy unwinding roll 22 reacts very slowly to the rapid and especially large changing transport speed of the embossed foil web 6 on the flatbed press 2 between a stationary speed and a fast forward speed, the speed difference between the forward speed at the flatbed press 2 and the web speed or unwinding speed at the unwinding roll 22 is equalized or compensated by an appropriate expansion or reduction in size of the foil loop 11 in the foil loop storage section 23.

[0162] Thus, in terms of the length of embossed foil web for foil advancement, in contrast to the unwinding device 21, only the inherent weight of the intermediately stored embossed foil web length in the form of a loop needs to be removed from the loop receiver 25. Furthermore, the loop-stored embossed foil web length is not mechanically held in the foil store. This allows the foil loop store 23 to provide the embossed foil web length with very low reaction times for a quick and fast foil advancement.

[0163] Furthermore, a sensor device 26 for detecting the length of the stored embossed foil web is assigned to the foil loop store 23. The vacuum device 24 is controlled on the basis of store data determined by the sensor device 26.

[0164] A flat braking and guiding wall 27 through which the embossed foil web 6 passes can be arranged between the foil loop storage 23 and the flatbed press 2 .

[0165] The braking and guiding wall 27 acts as a foil tensioning device and forms a guide surface along which the at least one embossed foil web 6 is guided. The guide surface can interact with a vacuum device, whereby a vacuum can be generated at the guide surface. The applied vacuum ensures that the embossed foil web 6 is abutted or sucked against the guide surface of the braking and guiding wall 27. The applied vacuum also ensures, in particular, the braking of the embossed foil web 6. The greater the applied vacuum, the greater the braking effect on the embossed foil web 6 and vice versa. The guide surface can be formed by a cloth-like or woven, breathable stationary layer. This ensures a gentle guiding of the sensitive embossed foil web 6 despite the physical contact between the embossed foil web 6 and the guide surface.

[0166] The foil tension between the braking and guiding wall 27 and the foil advancing device 41 can be controlled by the braking effect of a vacuum applied to the guide surface and acting on the passing embossed foil web 6. An increase in the vacuum on the guide surface results in a greater braking effect and therefore an increase in the foil tension.

[0167] As will be explained further below, controlled foil tension is particularly important in the area of ​​the flatbed press 2 as well as in the context of detecting printing marks, since it is the only thing that ensures that there is no arching of the embossing foil web 6 in the flatbed press 2 and thus positionally accurate or registered positioning as required.

[0168] However, the brake / guide wall 27 is not a required feature of the present invention. The foil web guiding and transporting device 7 further comprises a foil withdrawing device 40 for withdrawing the embossed foil web 6 from the flatbed press 1 .

[0169] The foil pull-out device 40 comprises a foil advancing device 41 arranged after the flatbed press 2 for carrying out the foil advance at the start of a new embossing cycle. The foil advancing device 41 can for example comprise a driven advancing roller or a driven advancing roller pair, along which the advancement of the embossed foil web 6 is effected.

[0170] Further downstream of the foil advancement device 41 , a foil withdrawal device 40 is provided with a take-up roll 42 for taking up the embossed foil web 6 .

[0171] The embossing foil web 6 is guided through the flat bed press 2 above the embossing table or above a sheet 12 positioned on the embossing table 3 and below the tool plate 4 via a foil web guiding and transport device 7 .

[0172] A deflection rod 15, which ensures an oblique upward deflection of the embossing foil web 6 from the horizontal transport path 17, is arranged at the exit of the flatbed press 2 in the transport direction T2 of the embossing foil web 6 above the transport path 18 of the sheet 12 and the embossing foil web 6.

[0173] The foil pull-out device 40 further comprises a peeling element 16 arranged downstream of the deflecting rod 15 in the conveying direction T1 of the sheet 12 and likewise above the conveying path 18 of the sheet 12. The deflecting rod 15 and the peeling element 16 are arranged in such a way that the conveying path 17 of the embossed foil web 6 passes between the deflecting rod 15 and the peeling element 16.

[0174] Furthermore, the foil pull-out device 40 between the deflection rod 15 or peeling element 16 and the foil advancing device 41 can be provided with a (further) flat braking and guiding wall 43 to ensure a constant foil tension between the foil advancing device 41 and the further braking and guiding wall 43.

[0175] The further braking and guiding wall 43 can be constructed in the same way as the braking and guiding wall 27 between the foil store 23 and the flatbed press 2. The further braking and guiding wall 43 is likewise not a mandatory feature of the device.

[0176] A print mark sensor 44, also called print mark reader, can be arranged between the foil advancing device 41 and the brake and guide wall 43. It detects the position of the print marks on the embossed foil web 6 for the purpose of accurate positioning of the registration of the embossed foil web 6 in the flatbed press 2. The print mark sensor 44 is arranged in the part of the foil transport path 17 between the brake and guide wall 43 and the foil advancing device 41, where a controlled foil tension prevails.

[0177] Alternatively, the print mark reader 28 can be disposed between the brake / guide wall 27 and the flatbed press 22. Alternatively, the print mark reader 13 can be disposed on the entrance side of the flatbed press 2. Alternatively, the print mark reader 13 can be disposed on the exit side of the flatbed press 2.

[0178] Common to all three positions of the print mark sensors 13, 14, 28 is the fact that a brake and guide wall 27 for the purpose of controlling the foil tension is arranged in front of them between the foil storage section 23 and the flatbed press 2.

[0179] The four printed mark sensors 23, 14, 28, 44 shown in alternative positions along the transport path 17 of the embossing foil web 6 are likewise not essential features of the present invention.

[0180] As mentioned above, at the start of an embossing cycle the embossed foil web 6 in the so-called foil advance is advanced by a defined advance length in the conveying direction T2 (advance direction) of the embossed foil web 6 by the foil advance device 41. For this procedure the length of the embossed foil web embossed in the preceding embossing cycle is conveyed or pulled away in the advance direction T2 away from the open flatbed press 2 and the length of the embossed foil web not yet embossed in the foil advance is conveyed or pulled into the open flatbed press 2. Furthermore, a new sheet 12 is conveyed from the sheet feeder 60 by the gripper beam 62 into the open flatbed press 2.

[0181] When the embossing foil web 6 is positioned in the flatbed press 2 in register with the sheet 12, the printed mark sensor 13, 14, 28 or 44 reads so-called printed marks on the embossing foil web 6. For this purpose, the transport of the embossing foil web 6 takes place with a reduced forward speed near the end of the foil advance (see also FIG. 4).

[0182] For this purpose, the print mark sensor 13, 14, 28 or 44 is arranged downstream of the braking and guiding wall 27 and 43, respectively, in the embossed foil web section with controlled foil tension.

[0183] As soon as the embossing foil web 6 and the sheet 12 are positioned (in correct registration) in the flatbed press 2, this is closed and the embossing procedure is carried out by forcing the tool plate 4 and the embossing table 3 together by the action of pressure and heat.

[0184] After completion of the embossing procedure, the flatbed press 2 is reopened and the embossed sheet 12 is conveyed out of the open flatbed press 2 together with the embossed embossing foil web length.

[0185] Here, the release of the embossed foil web 6 from the sheet 12 takes place at the exit of the flat-bed press 2 in the course of the foil advance. For this, the embossed sheet 12 is pulled out of the released flat-bed press 2 by the gripper beam 62 and also from the embossed foil web 6 by the foil advance. The embossed sheet 12 at the exit of the flat-bed press 2 is pulled away from the flat-bed press 2 in an approximately horizontal direction. The embossed foil web 6 is pulled away obliquely relative to the top, and a deflection rod 15 arranged on the exit side and above the embossed foil web 6 ensures a deflection obliquely upwards from the approximately horizontal guide.

[0186] Given a relatively easily peelable embossed foil web 6, the removal of the embossed foil web 6 from the sheet 12 is now effected by push-through separation, by pulling the embossed foil web 6 away obliquely upwards and simultaneously pulling the sheet 12 away horizontally. The embossed foil web 6 is thus deflected with a deflection rod 15.

[0187] However, if the embossed foil web 6 is not easily releasable, it remains attached to the sheet 12 and is pulled horizontally therewith. Thus, the peel point 10 or peel line is displaced downstream. The pulled embossed foil web 6 then abuts against a peel element 16 arranged further downstream on the sheet 12 at a distance therefrom. As a result, the embossed foil web 6 is pulled through under the peel element 16 during the formation of the peel loop 9 (see FIG. 2) until the holding force generated by the foil tension is greater than the peel force that builds up to peel the embossed foil web 6 from the sheet 12. Thus, the peel point 10 is downstream of the peel element 16.

[0188] Due to the formation of the peel loop 9, the embossed foil web 6 is peeled off from the sheet 12 at an acute peel angle α. The acute peel angle α, or the peeling elements ensuring the formation of the peel loop and thus the acute peel angle α, further prevents lifting and thus deformation of the sheet 2 by the adhered and pulled away upwards embossed foil web 6.

[0189] However, the embossed foil web excess length 8 is (later) pulled due to the peeling point 10 arranged downstream of the peeling element 16. The embossed foil web excess length 8 is the length portion of the embossed foil web 6 that is not embossed, which is (later) pulled through the flatbed press 2 beyond the specified advancement length of the foil advancement and is withdrawn from the flatbed press 2 at the exit side. This embossed foil web excess length 8 is not (later) pulled by the foil advancement device 41, since the foil advancement device 41 only performs the foil advancement at the specified advancement length.

[0190] Now, after completion of the peeling procedure, i.e. when the peeling point 10 has been released from the sheet 2, this embossed foil web excess length 8 is pulled back through the open flatbed press 2, opposite to the forward direction T2. ​​This is done by means of a foil loop storage 23, in which a vacuum device 24 during the peeling procedure exerts a permanent pulling tension on the embossed foil web 6 advancing in the direction of the flatbed press 2.

[0191] As soon as the embossed foil web 6 has been completely detached from the sheet 2, it bounces back in a whiplash manner in the direction of the foil loop store 23 due to the sudden drop in tension. The embossed foil web excess length 8 is pulled back in the direction of the foil loop store 23. An embossed foil web length corresponding to the pulled back embossed foil web excess length 8 is now formed in the foil loop store 23 and is intermediately stored for the next embossing cycle.

[0192] If a brake-guide wall 27 is arranged between the foil loop store 23 and the flatbed press 2, this is temporarily stopped during the pulling back of the foil web excess length so that the braking effect is lost. This can be achieved, for example, by simple venting of the brake-guide wall 27. This prevents the foil loop store 23 from being inhibited or even blocked due to the braking effect of the brake-guide wall 27, thereby preventing the retraction of the foil web excess length.

[0193] Now a new embossing cycle can start again. The embossed foil web excess length intermediately stored in the foil loop store 23 is further supplemented below by a further embossed foil web length from the unwinding roll 22, such that the total length of the foil web lengths intermediately stored in the foil loop store 23 corresponds at least to the advancement length.

[0194] The individual assemblies such as the unwinder, foil loop store, flatbed press, foil advancer and sheet transport, or the individual part processes of the flat embossing press, such as foil unwinding, storage and release of the embossed foil web lengths in and from the foil loop store, sheet feeding and transport, foil advance and embossing procedures, etc. are controlled via the machine control 80. For this purpose, the machine control 80 also processes inter alia sensor data from the print mark readers 13, 14, 28 or 44 and accommodates the sensor 26.

[0195] Basically, in order to emboss the sheet 12 in several areas, several embossing foil webs 6 can also be passed through the flatbed press simultaneously, in particular parallel to one another, in the flat embossing press 1. These embossing foil webs, driven by foil advancement devices 41, are each unwound from an unwinding roll 22, transported through the flatbed press 2 via a foil loop storage 23 arranged in front of the flatbed press 2 and wound up on a take-up roll in a foil withdrawal device 40.

[0196] 4 shows the schematic course of the sheet transport velocity profile 50 and the foil advance velocity profile 51 relative to each other. The velocity profiles are for illustration only and do not represent valid velocity courses.

[0197] After opening of the flatbed press 22 (reference numeral 52), first the sheet transport is started with a speed profile 50, whereby the sheet 12 is pulled out of the flatbed press 2 by the gripper beam 62. The foil advance starts with a speed profile 51 with a certain delay. Due to the delayed start of the foil advance, the sheet 12 together with the embossed foil web 6 adhering thereto is pulled towards the peeling element 16 and under the peeling element over a certain stretch while the peeling loop 9 is formed.

[0198] During the equal speed phase between the foil advance and the sheet transport, the embossed foil web 6 is peeled off from the sheet 12 during the formation of a constant peeling loop 9. When the embossed foil web 6 is completely released from the sheet 12 (reference number 53), the speed of the foil advance is also reduced to the so-called search speed. When the foil advance speed is reduced and the next search is performed, the printed mark sensor searches for a printed mark on the embossed foil web 6 in order to position it in precise register on the flatbed press 2 in preparation for the next embossing cycle.

[0199] If precise registration positioning of the embossed foil web 6 is not required, the search can be dispensed with. The speed of the foil advance is then reduced directly to 0 at the end of the foil advance.

[0200] The speed of the sheet transport does not decrease until there is some delay relative to the foil advance speed profile 51 near the end of the sheet transport, and then it decreases to zero. This is because the speed profile of the sheet transport is based on the so-called sheet rapport between the two gripper beams 62. Here, the path extension of the sheet bounce is significantly larger than the sheet length in the sheet transport direction T1.

[0201] After the foil advance and sheet transport are completed, the flatbed press 2 is closed again (reference numeral 54) for a new embossing cycle.

[0202] A foil advance velocity profile 51 can be envisaged that has a temporary velocity increase (not shown) just before the end of the peel procedure with the aim of reducing peel loops (not shown) before the velocity returns to zero or to the search velocity level near the end of the foil advance.

[0203] With regard to the details from the area of ​​the flatbed press 2 shown in Fig. 5, it is the case of a part of a flat embossing press 1. For example, it can be the flat embossing press 1 as shown in Fig. 1, which further comprises a foil tensioning device 90 according to the second aspect of the invention. However, the foil tensioning device 90 is not limited to the flat embossing press with a peeling element according to the first aspect of the invention, but is also suitable for other embodiments of the flat embossing press.

[0204] The flat embossing press according to FIG. 5 comprises a foil tensioning device 90 for tensioning the embossing foil web section 89 led through the flat-bed press 2 .

[0205] For this purpose, the foil tensioning device 90 comprises a first foil clamping device 93 for clamping the embossed foil web at a first clamping position 94, which is arranged in front of the flatbed press 2 in the conveying direction T2 of the embossed foil web. For this purpose, the first foil clamping device 93 comprises a first and a second clamping element 95, 27, between which the embossed foil web 6 can be guided and clamped. For this purpose, the first clamping element 95, for example a clamping roller, is movable and in particular pivotable towards the second clamping element 27 during the generation of the clamp. In the present embodiment example, the second clamping element 43 is formed by a brake and guide wall 27.

[0206] Furthermore, the foil tensioning device 90 comprises a second foil clamping device 96 for clamping the embossed foil web 6 at a second clamping position 98, which is arranged after the flatbed press 2 in the conveying direction T2 of the embossed foil web 6. For this, the second foil clamping device 96 comprises a first and a second clamping element 97, 43, between which the embossed foil web 6 can be guided and clamped. For this, the first clamping element 97, for example a clamping roller, is movable and in particular pivotable towards the second clamping element 43 during the generation of the clamp. The second clamping element 43 is formed in the present embodiment example by a foil brake 43.

[0207] Furthermore, the foil tensioning device 90 comprises a foil deflecting device 91 for deflecting the embossed foil web 6 from the foil-transport path 17 between the first clamping position 94 and the second clamping position 98 for controlling the foil tension and for controlled stretching of the foil. The foil deflecting device 91 is arranged in front of the flatbed press 2 when considered in the transport direction T2 of the embossed foil web 6.

[0208] The foil deflection device 91 comprises a foil deflection element 92 which is pivotable transversely to the foil transport path 17 towards the embossed foil web 6. For this purpose, the foil deflection element 92 is pivotally mounted via a pivot axis.

[0209] Furthermore, the foil deflection device 90 comprises two counterholder elements 99 in the form of counterholder rollers arranged at a distance from one another along the conveying direction T2 of the embossed foil web 6. These are arranged on the side of the embossed foil web 6 facing away from the foil deflection element 92. A deflection section 6 of the embossed foil web 6 is formed between the counterholder rollers 99.

[0210] The counterholder rollers 99 ensure that the embossing foil web 6 is deflected only between the counterholder rollers 99. Here, the foil deflecting element 92 is pivotable between the two counterholder rollers 99 towards the embossing foil web 6.

[0211] In order to deflect the embossed foil web 6, the foil deflection element 92 is pivoted transversely relative to the foil-transport path 17 towards the embossed foil web 6. Here, the foil deflection element 92 pushes the embossed foil web 6 laterally out of the foil-transport path 17 and deflects it laterally. Here, the embossed foil web 6 is deflected at a counterholder roller 99, i.e. deflected outwardly from the foil-transport path 17. The laterally deflected embossed foil web 6 in this case forms laterally protruding foil loops.

[0212] The deflection of the embossed foil web 6 results in a longer path stretch of the embossed foil web. Since the embossed foil web 6 is clamped before and after the foil deflection device 91 considered in the conveying direction T2, the additional path stretch for the lateral deflection of the embossed foil web 6 can only be provided by tensioning or stretching the embossed foil web section 89 that is led through the flatbed press. Here, the tension and thus the stretch of the embossed foil web section 89 is controlled by the degree of deflection of the embossed foil web 6.

Claims

1. A flat embossing press (1) for embossing a flat material (12), comprising: A flatbed press (2) having a tool plate (4) and an embossing table (3); a foil web guiding and transporting device (7) for guiding at least one embossed foil web (6) along a foil transport path (17) onto the embossing table (3) of the flat bed press (2); a flat material guide (13) for guiding the flat material (12) through the flat bed press (2) along a flat material transport path (18); A control device (80) for operating the flat embossing press (1); Equipped with The conveying direction (T １ 1. A flat embossing printing machine (1) comprising: a foil web guiding and transporting device (7) behind the flat bed press (2) in said flat embossing printing machine (1), the foil web guiding and transporting device (7) comprising a peeling element (16) arranged above the flat material transport path (18) and behind the foil transport path (17) for holding back and peeling off the embossed foil web (6) from the flat material (12) as the flat material (12) is transported away from the flat bed press (2).

2. The embossed foil web (6) adhering to the embossed flat material (12) conveyed away from the flat bed press (2) is in particular inclined in the conveying direction (T) of the flat material (12) coming from the peeling element (16). １ 2. The flat embossing press (1) according to claim 1, characterized in that the peeling element (16) is arranged with respect to the flat material transport path (18) such that during the formation of an open peeling loop (9) extending downstream of the peeling element (16), the peeling element (16) holds back and thus peels off the flat material transport path (18).

3. The foil web guiding and transporting device (7) is arranged to guide the flat material (12) in the transport direction (T １ ) of the flat material (12) in order to deflect the embossed foil web (6) from the conveying direction (T １ 3. The flat embossing printing machine (1) according to claim 1, further comprising a deflection element (15) arranged at the outlet of the flat bed press (2) above the flat material transport path (18) and in front of the peeling element (16), wherein the embossing foil web (6) is guided between the deflection element (15) and the peeling element (16).

4. 4. The flat embossing press (1) according to claim 3, characterized in that the deflecting element (15) is arranged at a distance to the flat material transport path (18).

5. The flat embossing press (1) according to any one of claims 1 to 4, characterized in that the peeling element (16) is arranged at a distance to the flat material transport path (18).

6. The flat embossing press (1) according to any one of claims 1 to 5, characterized in that the peeling element (16) is arranged at a distance of at least 1 mm, in particular at least 2 mm, more in particular at least 3 mm to the flat material transport path (18).

7. The flat embossing press (1) according to any one of claims 1 to 6, characterized in that the peeling element (16) is arranged at a distance of 30 mm or less, in particular 20 mm or less, more in particular 10 mm or less to the flat material transport path (18).

8. The flat embossing press (1) according to any one of claims 1 to 7, characterized in that the peeling element (16) forms a deflection surface, in particular an arcuate one, for deflecting the embossing foil web (6).

9. The flat embossing press (1) according to any one of claims 1 to 8, characterized in that the flat embossing press (1) comprises an unwinding device (21) for unwinding the embossing foil web (6) from an unwinding roll (22).

10. The flat embossing press (1) is adapted to move the embossing foil web (6) in the conveying direction (T ２ 10. The flat embossing press (1) according to claim 9, further comprising a foil storage (23) arranged in front of the flat bed press (2) in the press (1), in particular between the unwinding device (21) and the flat bed press (2).

11. 11. The flat embossing printing machine (1) according to claim 10, characterized in that the foil store (23) is in particular equipped with a store-former (24) for filling the foil store (23) with an embossing foil web length.

12. A method for operating a flat embossing press (1) according to any one of claims 1 to 11, comprising the steps of: positioning and bringing together the embossing foil web (6) and the flat material (12) in the flat bed press (2), and transferring an embossed picture (57) from the embossing foil web (6) onto the flat material (12) by an embossing procedure; After the embossing step, the flat material (12) is １ ) along the flat material transport path (18) through the peeling element (16) and away from the open flat bed press (2), the embossed foil web (6) being adhered to and carried along with the flat material (12) impinges on the peeling element (16) activating peeling of the embossed foil web (16) from the flat material (12).

13. The embossed foil web (6) adhering to the flat material (12) comes from the peeling element (16) and moves in the conveying direction (T １ 13. The method according to claim 12, characterized in that the material is peeled off from the flat material (12) during the formation of an open peel loop (9) extending downstream of the

14. The embossed foil web excess length (8) advancing through the flatbed press (2) is inclined in the foil advance direction (T ２ 14. The method according to claim 12 or 13, characterized in that the foil is pulled back again in the opposite direction to the direction of travel (22) and is intermediately stored in the foil storage (23), in particular for a subsequent embossing procedure.

15. 13. A method according to claim 12, characterized in that the embossed foil web excess length (8) is pulled back by the store-former (24) of the foil store (23).

16. A flat embossing press (1) for embossing a flat material (12), in particular according to any one of claims 1 to 15, comprising: A flatbed press (2) having a tool plate (4) and an embossing table (3); a foil web guiding and transporting device (7) for guiding at least one embossed foil web (6) along a foil transport path (17) onto the embossing table (3) of the flat bed press (2); a flat material guide (13) for guiding the flat material (12) through the flat bed press (2) along a flat material transport path (18); a foil tensioning device (90) for tensioning the embossed foil web section (89) guided through said flat bed press (2); A control device (80) for operating the flat embossing press (1); Equipped with The foil tensioning device (90) comprises: The conveying direction (T ２ a foil clamping device (93) for clamping at least one of the embossed foil webs (6) at a clamping position (94) arranged in front of the flatbed press (2) when considered in relation to the flatbed press (2); In order to control the foil tension, the embossed foil web (6) is ２ a foil deflection device (91) for deflecting at least one of the embossed foil webs (6) from the foil transport path (17) after the clamping position (94) considered in the case of A flat embossing printing machine (1), comprising:

17. 17. The flat embossing press (1) according to claim 16, characterized in that the foil deflection device (91) is designed to deflect at least one of the embossing foil webs (6) from the foil transport path (17) between the clamping position (94) and the flat bed press (2).

18. The foil clamping device (93) is a first foil clamping device, the clamping position (94) is a first clamping position, and the foil tensioning device (90) is configured to tension the foil in the conveying direction (T ２ 18. The flat-embossing printing machine (1) according to claim 16, further comprising a second foil clamping device (96) for clamping the at least one embossing foil web (6) at a second clamping position (98) arranged after the flat-bed press (2) at a first clamping position (94, 98), and wherein the foil deflecting device (91) is designed to deflect the at least one embossing foil web (6) from the foil-transport path (17) between the first and second clamping positions (94, 98).

19. The foil deflection device (91) is adapted to deflect the at least one embossed foil web (6) in the conveying direction (T ２ The flat embossing press (1) according to any one of claims 16 to 18, characterized in that it is arranged in front of the flat bed press (2) when considered in relation to the flat bed press (2).

20. The flat embossing printing machine (1) according to any one of claims 16 to 19, characterized in that the foil deflection device (91) comprises a foil deflection element (92) which is movable, in particular pivotable, with a movement component transverse to the foil-transport path (17) during deflection of the at least one embossing foil web (6).

21. The foil deflection device (91) is arranged to deflect the embossed foil web (6) in the conveying direction (T ２ 21. The flat embossing printing machine (1) according to claim 16, further comprising two counterholder elements (99) spaced apart from each other at a distance 20 cm from the embossing foil web (6) and arranged on the opposite side of the embossing foil web (6) to the foil deflection element (92), between which a deflection section of the embossing foil web (6) is formed.

22. The flat embossing press (1) according to any one of claims 16 to 21, characterized in that the flat embossing press (1) forms several foil transport paths (17) for leading several embossing foil webs (6) adjacent to one another through the flat bed press (2), and a foil deflection device (91) for individual setting of the foil tension for each embossing foil web (6) is assigned to each foil transport path (17).

23. A method for operating a flat embossing press (1) according to any one of claims 16 to 22, characterized in that at least one of the embossing foil webs (6) and the flat material (12) are positioned in the flat bed press (2) and brought together by closing the flat bed press (2), and an embossed picture (57) is transferred from the at least one of the embossing foil webs (6) onto the flat material (12) by an embossing procedure, 13. The method of claim 12, wherein before closing the flat bed press (2), at least one of the embossed foil webs (6) is clamped at the clamping locations (94), in particular at the first and second clamping locations (94, 98), and afterwards the foil deflection element (92) is moved, in particular pivoted, towards the embossed foil web (6), the foil deflection element (92) deflecting the at least one of the embossed foil webs (6) transversely to the foil transport path (17) until the embossed foil web section (89) led through the flat bed press (2) has a predetermined tension.

Images