EP2128060B1 - Film impression machine - Google Patents

Abstract

The machine has an impression unit provided with a movable impression base (130), and an impression cylinder that is arranged with horizontal axis of rotation above a machine bed by a film unit with control devices. A film storage container (136) receives a supply roller (134), and a film brake mechanism (200) generates web tension between the supply roller and the control device of the film unit. The film brake mechanism produces a braking force at an impression foil course at a distance from the supply roller.

Description

Field of the invention

The invention relates to a foil stamping machine according to the preamble of claim 1.

Description of the Related Art

In hot embossing, a material layer to be embossed, for example a printing material sheet or a printing material web, is passed through an embossing gap in a foil embossing machine, which is between an embossing tool carrier device and a counterpressure element, for. B. a counter-pressure cylinder or a counter-pressure plate is formed. The embossing tool carrier device carries one or more embossing tools which can be heated during hot stamping by means of a heating device. Depending on the type of embossing device, the embossing tool carrier device can, for example, have a flat shape - in the case of so-called round-flat machines or flat-flat machines - or a cylindrical one Form - in so-called round-round machines or rotary machines - have.

The field of application of the claimed invention are film embossing machines in round-flat technology. Here, the embossing tool carrying device is formed by an embossing foundation guided linearly in a horizontal direction in a machine bed of the machine. In circular-flat machines, this usually works together with a stamping cylinder arranged with a horizontal axis of rotation above the machine bed.

During operation of the foil embossing machine, at least one stamping foil web is guided through the embossing gap in such a way that it has the same state of movement during the embossing interval as the material layer to be embossed. During the embossing interval, embossing material located on the embossing foil web, for example discrete stamping units lying one behind another, such as images, texts and / or holograms, or a part of a color layer or metal layer to be coated, is transferred to the material layer under the action of pressure and temperature.

The stamping foil web is drawn off and forwarded by a film transport device from a normally roll-shaped film supply, the spent stamping foil is removed and disposed of. The film transport device, which will also be referred to as a "film plant" hereinafter, has one or more control devices actively involved in the control of the film web movement to accurately determine the preferred length of the embossing film web in film advancement according to a control program. The active control devices include, for example, the so-called clock rollers (or control rollers), which are in slip-free rolling contact with the embossing foil web and are precisely controlled with respect to their rotation angle. In addition to the active control devices, a plurality of passive devices, eg deflection rollers and / or air deflection rods, are generally provided in the film factory. to determine the course of the embossing foil web (s) through the film factory.

In general, successive embossing on the substrate have a certain distance from each other. Since it would be uneconomical to keep the corresponding embossing units or ink layer areas at the same distance on the embossing film web, it is desirable to optimize film consumption that one behind the other to be embossed ink layer areas or consecutive embossing units are closer together on the embossing film than consecutive embossing on the substrate. This goal can be achieved by a discontinuous film preference. During the stamping interval, the stamping foil web is not moved with respect to the stamping foundation. In the case of round-flat machines, the embossing foil web moves with the embossing foundation from a starting position, which is taken before the beginning of the embossing interval, to a stop position, which is taken after the end of the embossing interval before the start of the return movement of the embossing foundation. The film advantage, in which fresh stamping foil web is withdrawn from the film supply, normally takes place after the end of a stamping interval, while the stamping foundation is in its return movement from its stop position to the starting position. Even with flat flat machines, the film preference takes place between the embossing intervals.

For a good embossing quality, perfect mechanical processes in the machine, a uniform pressure distribution in the embossing gap, a uniform temperature distribution and the use of suitable embossing foils are prerequisites. Of great importance are also the film tension (web tension) and thus the film run. With discontinuous film advance special measures are required to produce a sufficient web tension. The film tension should on the one hand be so great that at no time can a loose form in the film web. On the other hand, with increasing web tension, the tendency for wrinkling to increase in the longitudinal direction, ie in the running direction of the embossing film webs, increases. The film tension is built up between the film advantages, that is to say the cycle rollers of the film factory, and the region of the film unwinding, that is to say the region of the supply roll in which fresh (unused) embossing film web is kept.

In the film embossing machines with flat embossing foundation considered here, the film supply is located in a film storage container. This is attached to the front of the stamping foundation in round-flat machines and moves back and forth with the stamping foundation. Since it can happen that foils of different colors for different motif sizes lie next to one another in the foil reservoir, the foil consumption during production can be different for each supply roll. In this case, the roll diameter of the individual supply rolls changes differently during production. Therefore, in film embossing machines in round-flat technology, film brake devices are provided for producing web tension between the supply reels and a first control device of the film work immediately following the supply reel. The film brake devices can be designed so that each supply roll within the film supply device can be braked individually.

In a known film brake device separating plates are mounted within the film storage container between the adjacent supply rolls, which can be pressed with adjustable spring force to the end faces of supply rolls. With this proven and mechanically robust solution, the braking force decreases as the diameter of the supply rolls decreases. Therefore, usually needs Occasionally, the machine may be stopped during production to make the dividers stronger and restore the required braking force. These downtimes can significantly reduce the net output of the foil stamping machine.

Other film brake devices engage in the center of the supply roll, so for example on a cylindrical cardboard tube, which serves as a carrier for the embossed foil web wound thereon. For this purpose, mechanical, electrical and / or magnetic brakes are usually used. The components required for this must be found in the film reservoir. In particular, when multiple supply rolls are to be kept next to each other in the film storage container, there may be space problems, so that this braking technology can be used only with a correspondingly large distance between the rollers. Since large distances between the rollers are not acceptable or possible with many embossing motifs, the possible uses of such electrical or magnetic film brake devices are limited. In addition, as the supply roll becomes smaller, the mass to be braked decreases, so that the braking force should be changed accordingly.

The patent US 3,721,185 shows a foil stamping machine with an embossing mill comprising a movable flat embossing foundation and as a counter-pressure element embossing cylinder, which is arranged with a horizontal axis of rotation above the machine bed. At a front side of the embossing foundation, a film storage container for receiving at least one supply roll is attached, which is movable back and forth with the embossing foundation.

The EP 1 593 503 A2 describes a flat-plate flat embossing machine in which the embossing has a vertically movable embossing table, which cooperates with a plate-shaped counter-pressure element. The film web guide for this flat embossing printing machine has film webs, which are guided by unwinding rollers on the embossing table. The film web guide has a braking and guide wall in front of the embossing table and film feed devices for a plurality of film webs after the embossing table. Between the unwinding rollers and the embossing table, at least one flat braking and guiding wall acts as a film tensioning device.

The FR 2 607 072 describes another foil embossing machine in round-flat technique.

TASK AND SOLUTION

It is an object of the invention to provide a foil stamping machine with a flat stamping foundation which guarantees very good stamping quality with high productivity. In particular, the foil stamping machine should be easy and convenient to use and easy to convert to adapt to different stamping tasks.

To achieve this object, the invention provides a foil stamping machine having the features of claim 1.

Advantageous developments are specified in the dependent claims. The wording of all claims is incorporated herein by reference.

A foil embossing machine according to the claimed invention is distinguished from generic foil embossing machines of the prior art in that it has a foil brake device, which is designed to generate a braking force acting on the embossing foil web at a distance from the supply roll. According to this embodiment, the embossing film is thus not slowed down at the supply roll, but at the already unwound from the supply roll film web. Thus, the force exerted by the film brake device on the film web braking force is independent of the roll diameter of the respective supply roll and thus independent of the film consumption.

In comparison to the known film brake devices with dividing plates mentioned at the outset, the machine downtimes can thereby be considerably reduced, as a result of which the productivity of the film embossing machine is considerably improved. Compared to the known solutions with brake application in the center of the supply roll, restrictions on the mutual spacing of supply rolls are eliminated by the invention, so that the embossing film machine is much more flexible and can be used for a wide variety of embossing tasks.

The braking force preferably acts on the respective embossing foil web immediately after the supply roll, that is still in the region of the foil supply container. For this purpose, a brake-effective assembly of the film brake device between a directly serving for receiving supply rolls, e.g. arranged trough-shaped roller receptacle of the film storage container and the embossing foundation.

In one embodiment, the film brake device is designed as a pneumatic film brake device. The braking force can thus be generated and adjusted with the aid of the generation of differences in air pressure. A pneumatic film brake device can attack particularly gently and gently on the sensitive embossing film webs. It can also be constructively relatively easily constructed without moving parts and can therefore be integrated in a small footprint in the limited space available in the area of the film storage container.

However, the film brake device can also be constructed with the aid of movable brake elements which engage the stamping foil webs and can be controlled, for example, mechanically, electrically or electromechanically. .

The pneumatic film brake device may have at least one perforated film guiding device which has a front surface designed as a guide surface for embossing film webs, which has a plurality of perforations through the back of the film guiding device in a working region, the back side being connected or connectable to a vacuum generator. In a simple embodiment, the film guiding device may be a perforated sheet metal part in which a relatively narrow strip with perforations extends over the entire useful width of the stamping foundation.

A particularly high flexibility in the use of the foil embossing machine is achieved in some embodiments in that the foil brake device has a measured across the direction of the embossing foil overall useful width and is divided over the total useful width in several individually adjustable and thus independently usable zones. It can e.g. two, three, four, five, six, or more zones. Preferably, between 5 and 20 zones are provided, in particular between 8 and 16 zones. The zones may have identical or different zone widths. For example, if only a portion of the total useful width is to be utilized, in one embodiment, unused areas of a perforated film guide may be mechanically or otherwise closed or deactivated to avoid the pneumatic film brake being in those areas that are not covered by a film web are covered, false air pulls.

A division of the total useful width in independently usable zones is also used in other embodiments to adjust the braking force of the film brake device in the individual zones individually and independently of other zones and possibly to change. In the case of a pneumatic film brake device, this can be achieved, for example, by using one or more venturi nozzles per zone.

In some embodiments, the film brake device is configured for adjustment of the braking force acting on the embossing film web during operation of the film embossing machine. When using a pneumatic film brake device, this can be achieved in a simple manner by setting or adjusting the air pressure or negative pressure responsible for the braking force generation. The braking force or the negative pressure responsible for this can be changed, for example, via a central valve while the machine is running become. If, for example, the suction force is increased in embodiments with a perforated film guiding device, the frictional force which builds up between the perforated guiding surface and the embossing film web sliding thereon also increases correspondingly. The adjustment or adjustment of the braking force acting on the stamping foil web can also be realized in the case of non-pneumatic film brake devices, for example by electrical actuation of drives of corresponding brake elements.

In some embodiments, in addition to the film brake device acting on the film web, at least one roller braking device acting directly on a supply roll is provided. For example, dividing plates or other subdivision devices can be used between the film rolls, which ensure precise lateral positioning of the film rolls, that is to say lateral guidance transversely to the unwinding direction. The side guide elements can be pressed with little force to the end faces of the film rolls, for example by means of a suitable spring load. The basic braking force caused by these direct brake devices can be very low, so that they do not have to be changed during the production process. Due to the action of the direct braking device, the supply rolls can be easily braked so that they do not run after a film advantage and in the direction reversal of the embossing foundation.

In the following, some advantageous features of suitable film works will be explained. These can advantageously be used in embodiments of the invention in conjunction with a film brake device acting directly on the stamping foil web. However, they are useful independently or in combination regardless of the type of the film brake device and therefore can be used with advantage in foil stamping machines of the prior art.

During the embossing interval, the embossing film web must be located in the embossing gap between the underlying embossing foundation and the embossing cylinder rolling over it or a flat counterpressure element which carries the printing material. The intended for embossing section of the embossing film web spans itself between the film supply and the film supply immediately following the first control device of the film factory. In some embodiments, the first control device of the film work immediately following the film supply is a deflecting device fixedly mounted in relation to the machine bed. This deflection does not move with the embossing foundation, but is fixed relative to the position relative to the machine bed. It can thereby be achieved that the fresh, still unused embossing foil web is substantially only during the embossing interval in the immediate vicinity or on the types of heated embossing foundation, outside the embossing interval, however, can be performed at a sufficient distance from the heated surface, so that a possibly harmful pre-activation of the sensitive material is avoided. As a result, the embossing quality can be improved, in particular when using sensitive embossing foils.

In some embodiments, one of the first control device immediately following second control device of the film factory is arranged at a large distance above the plane of the first control device, so that the embossing film web can be led away immediately behind the first control device steeply upwards. In this way, on the one hand, the thermal pre-activation of the embossing foil web is avoided, and this also improves the accessibility of the embossing foundation in comparison to conventional solutions in which the embossing foil web is permanently guided at a short distance above the embossing foundation. The vertical distance between the Levels of the first control device and the second control device may be, for example, more than 30 cm or more than 40 cm or more than 50 cm or more than 60 cm or more than 70 cm or more than 80 cm.

The frame-fixed deflection device can be designed, for example, as a movably mounted deflection roller, if appropriate also as a permanently installed deflection rod. In some embodiments, the frame-fixed deflection device is a so-called air rod, which is understood here to mean a device for contactless guiding of a material web, in which an air cushion is formed between the curved guide surface of the air rod and the guided material web. The wall of the air rod is provided for this purpose at least in a guide region with passage openings through which compressed air pressed into the interior of the air rod can escape.

In some embodiments, the film plant has a preferred with respect to the machine bed frame mounted preferred package with at least one controllable with respect to their rotation angle clock roller. Compared with an equally possible attachment of timing rollers on the embossing foundations, this results in the advantage that the mass of the timing rollers in the reciprocating motion of the embossing foundation does not have to be moved, so that due to lower inertial forces a more precise attitude control of the embossing foundation is possible. Preferably, the preferred package is disposed a relatively large distance of at least 40 cm or at least 50 cm above the plane of travel of the embossing foundation, so that the accessibility of the embossing foundation for maintenance or for the exchange of embossing types by the preferred package is not hindered.

To compensate for the discontinuous movement of the embossing foil web in the region of the embossing gap and the area of the preferred package (Stroke Rolling), the film factory usually has a film memory with a variable memory length. This film storage is preferably arranged between the first control device of the film factory and the preferred package. The film storage can be mounted fixed to the frame like the preferred package. Preferably, the film storage is arranged at a distance of at least 40 cm or at least 50 cm above the plane of movement of the embossing foundation, so that the accessibility of the embossing foundation is not hindered by the film memory.

The film store is preferably designed as a horizon store. The term "horizontal storage" here means that the direction in which changes the effective storage length of the film storage during use, is oriented substantially horizontally. The film storage, in some embodiments, includes a dancer roll system having rollers movable in groups toward and away from each other, between which film loop sections are passed. The horizontal orientation of the film storage makes it possible to provide a relatively large vertical distance between the plane of movement of the embossing foundation and the film store arranged above it, even with a large storage capacity of the film storage at a total compact height dimensions of the machine, so that the embossing foundation for maintenance or retooling without obstruction by the film storage is accessible.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

shows a schematic side view of an embodiment of a foil stamping machine in round-flat technique; and

Fig. 2

shows a schematic, oblique perspective view of the area of moving with the embossing foundation film supply device with a arranged between the film supply and embossing foundation, pneumatic film brake device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a schematic side view of an embodiment of a sheet-processing foil stamping machine in round-flat technique. The foil embossing machine 100 has an embossing unit 110, which comprises an embossing foundation 130 guided horizontally movably on the machine bed 120 of the machine and an embossing cylinder 140 arranged with a horizontal axis of rotation above the machine bed and serving as a counterpressure element. Between the embossing foundation 130 and the embossing cylinder 140, an embossing gap 145 is temporarily formed during operation of the device when the embossing foundation is located below the embossing cylinder in its horizontal linear reciprocating movement.

The embossing foundation 130 is reciprocated horizontally by a drive arranged inside the machine bed along linear guides and is intended to carry replaceable embossing tools (types) 132 on its upper side facing the embossing cylinder. In the height-adjustable embossing foundation is a heater integrated, which makes it possible to heat the embossing tools during operation to temperatures well above 100 ° C.

The sheets of material to be printed on a supply stack shown on the right or staple stack 162 with the side to be embossed held up and are individually supplied to the embossing cylinder 140 of the embossing unit during operation of the film embossing machine via an inclined feed table 164. On the circumference of the embossing cylinder are gripper systems 142, each grabbing the leading edge of a sheet and pull on the lateral surface 144 of the uniformly rotating embossing cylinder. During the gripping process, an alignment of the printing material sheet takes place. The hanging with its leading edge on the circumference of the embossing cylinder arc is guided in the rotation direction shown (arrow) of the printing cylinder from left to right through the embossing gap 145 and thereby embossed in a manner to be explained later. After the embossing interval, the embossed material sheet is transferred to a delivery system 164, which successively conveys the printed material sheets onto the storage stack 166 arranged below the feed stack.

When passing through the embossing gap (in the figure from left to right), the surface of the material sheet to be printed has a speed which (depending on the material thickness of the sheet) substantially corresponds to the peripheral speed of the lateral surface 144 of the continuously rotating embossing cylinder.

During operation of the foil embossing machine, at least one embossing foil web 170 is moved through the embossing gap 145. Those devices which guide the embossing foil web and control the preferential movement of the embossing foil web belong to the so-called film plant 180 of the foil embossing machine. The embossing foil web is usually very thin (between 10 μm and 20 μm) and usually consists of one relatively viscous carrier film made of plastic, on the front side of a layer system with a thermally activated separation layer, the actual embossing layer (for example, ink layer or metal layer or hologram or frames), and a thermally activated hot melt adhesive layer is applied, which forms the substrate facing the substrate 172 of the embossing film.

The fresh, as yet unused embossing foils are in the form of supply rolls 134 in a trough-shaped foil storage bin 136, which is attached to the front of the embossing foundation and together with this during the embossing interval, i. during the printing phase, runs under the embossing cylinder from left to right. Since the foil storage container 136 projects beyond the level of the embossing types 132 with its upper side, a recess 146 is provided in the embossing cylinder 140 outside the circumferential region 144 which is required during embossing, which allows the foil supply container 136 to be passed under this without contact with the embossing cylinder.

During a stamping interval, the stamping foil web runs through the stamping gap at the same speed as the material sheet to be printed. For this purpose, the linearly displaceable embossing foundation 130 is accelerated from its starting position A shown in the figure to the left of the embossing cylinder so that the embossing tools also have the same speed during the embossing interval as the material sheet to be embossed and the embossing foil web guided between the material sheet and the embossing tool. During the embossing interval, under the influence of pressure and temperature, the embossing unit (for example part of a color coat) is transferred to the material sheet. After the embossing foundation has been moved in line during the embossing interval in synchronism with the sheet of material and the embossing foil web, it is decelerated after completion of the embossing interval until it reaches the stop position B shown in dashed lines on the right. During the Returning to the start position A, the movement is coordinated so that the returning embossing foundation with the film supply attached thereto runs again through the recess 146 in the embossing cylinder, so that the return of the embossing foundation is possible without contact with the embossing film or the embossing cylinder.

During the trace (from A to B), the embossing foil web does not move relative to the embossing foundation and is only carried along by it. During the subsequent return (from B to A), the film preference takes place by a predefinable, subject-dependent preferred route. The preferred film is controlled by the clock rollers, which rotate for this purpose by a predetermined angle of rotation. With the aid of a film memory 184 explained later, a length compensation takes place in order to ensure sufficient web tension at all times.

The sheeting 180 may include a plurality, e.g. Two, three, four, five or six adjacent embossing foil paths run parallel. The foil unit allows the embossing foil web to be stationary during the embossing interval without relative speed to the embossing foundation and to deduct spent embossing foil in the following idling phase by one motif length in the direction of disposal and thereby to provide fresh embossing foil for the subsequent embossing interval.

In the film plant 180 of the foil embossing machine 100 coming from the film supply 134 embossing foil webs are first on a fixed to the machine frame, ie fixed to the frame deflection bar 182 and then steeply up through a foil memory 184 through to the so-called clock rollers 186, which control the film preference and their rotation angle thereto can be controlled by means of the controller 188 of the foil stamping machine. The timing rollers only rotate in one direction to produce the film advantage. Outside the preferential phases, they stand still. A reverse rotation is not intended. It can be provided up to three clock rollers, so that up to three independent film web movements can be realized. Each stroke roller can carry several film webs if they have the same motion profile. The clock rollers are combined in a so-called preferred package 189, which in the film embossing machine 100 fixed to the frame, ie on the machine frame itself, is attached. From the cycle rollers, the used film webs are guided to take-up rollers 190, which are also mounted fixed to the frame.

During operation of the machine, the embossing foundation 130, as already described above, moves from the starting position A shown below to the embossing cylinder 140 to the stopping position B shown on the right in dashed lines. The supply rollers 134 located on the front side of the embossing foundation in the film storage container 136 are carried along and under passed through the embossing cylinder. During this forward movement, the embossing foundation 130 moves under the frame-fixed deflection bar 182. The film supply with the embossing foundation moves with. The stamping foil web is not moved in this phase relative to the stamping foundation. Between the advancing supply roll 134 and the frame-fixed deflection bar 182, a stamping foil web section is spanned with increasing length, since the distance between the supply roll and the frame-fixed deflecting device increases. A removal of the embossing foil web from the supply roll is prevented in this phase by a later explained in more detail foil brake device whose brake active assembly 210 holds the embossing foil web between reservoir 136 and the heated part of the embossing foundation. During the embossing interval, the film supply is already beyond the embossing cylinder, so that the embossing film web 170 extends from the film supply 134 to the frame-fixed deflecting rod 182 between the underlying embossing foundation 130 and the embossing cylinder 140 arranged above it. This will be in Fig. 1 illustrated by the dashed lines shown 170 'of the stamping foil.

In the phase of advancement of the embossing foundation (from left to right or from A to B, respectively), the storage length of the film store 184 shortens, i. the foil store releases foil. In the return movement leading from right to left (i.e., from B to A), the storage length of the film store 184 increases again (film store receives film), so that the embossing film web has sufficient web tension at all times. In the phase of the backward movement of the film preference also takes place by the clock rollers rotate by a predetermined angle. The film brake is deactivated in this phase so that film web can be pulled off the supply roll.

The only a few centimeters above the plane of movement of the embossing foundation mounted fixed to the frame deflection bar 182 is formed as an air rod or blower tube, so that the sensitive front side 172 of the embossing foil web is gently guided on a formed between embossing foil web and deflection air cushion. The air rod 182 forms the first, immediately following the film supply control device of the film factory. The immediately following without the interposition of other guide devices second control device 183 of the film factory is arranged at a great distance of more than 40 cm or more than 50 cm or more than 60 cm or more than 70 cm above the plane of movement of the embossing foundation, so that the embossing foil web immediately after the first control device 182 is led away steeply upwards.

The immediately following film memory 184 is designed as a horizontal memory and comprises groups of first and second dancer rollers, by means of a drive, not shown in detail, synchronously with the film web movement in the horizontal direction (arrows) can be moved towards and away from each other to vary the (horizontally aligned) memory length of the horizontal memory. The frame-mounted film storage is also located far above the stamping foundation. The tact rollers 186, which are combined in the preferred package 189, are mounted fixed to the frame above the horizontal store 184 and deliver the embossing foil web to frame-mounted take-up reel rollers 190, which rotate synchronously with the cycle rollers when film advancement takes place.

The special type of film guide has advantages over conventional systems, among other things in the quality of the embossing result and handling. Because the embossing foil webs are led away steeply upwards immediately behind the first control device 182, they are not permanently exposed to the heat of the embossing tools attached to the embossing foundation but only directly during the embossing process. They are therefore less preactivated. This has the consequence that when using certain film grades an improvement in the embossing result and an increase in performance compared to conventional foil stamping machines can be achieved. The large clear distance D between the plane of movement of the embossing foundation and the lowest-lying components of the film memory also opens up an optimal accessibility of the embossing foundation and thus facilitates the operation of the machine. For example, a readjustment of the embossing tools is possible without any obstruction by the film. For easy insertion of a new film web in the film storage the mutually movable dancer roller groups can be moved into a special threading. The entire preferred package and the film storage are located in an area far above the stamping foundation and therefore do not interfere with access to the stamping foundation.

FIG. 2 shows a diagonal perspective, schematic detail view of the area of the mounted on the front of the embossing foundation 130 film reservoir 136. This has a generally trough-shaped, upwardly open receptacle, which in the exemplary case a trapezoidal cross-section with sloping downwardly converging, flat side surfaces and a flat bottom surface. In the film storage container there is a supply roll 134 with unconsumed embossing film web, from which an embossing film web portion 170 is guided away substantially parallel to the top 131 of the embossing foundation 130 in the direction of the frame-fixed first deflecting rod 182 of the film factory.

Immediately after the embossing foundation facing inclined surface 137 of the film storage container, a brake active assembly 210 of a pneumatic film brake device 200 is disposed between this and the embossing foundation. The brake-active assembly is designed as a so-called vacuum bar 210. It has a corpus made of thermally insulating plastic with a rectangular cross section, extends transversely to the direction of the embossing foil webs substantially over the entire width of the embossing foundation and is in the direction of the film transport V (arrow) is relatively narrow, for example between 3 and 10 cm narrow. The upper horizontally mounted end cap of the vacuum bar is a sheet steel part and has a plurality of regularly spaced perforations 211 which pass from the flat top to the otherwise closed interior of the vacuum bar. The circular through holes typically have typical diameters between about 0.5 mm and 3 to 4 mm and are grouped in a regular or irregular arrangement so that at certain intervals perforation-free strips 212 are present, seen in the preferred direction V of the embossing film web have no perforations , The closed to the perforations interior of the vacuum bar is connected to a vacuum generator 220th the film brake device connected, for example, to a vacuum pump.

The stamped foil web 170 drawn off from the film supply runs with its relatively insensitive back directly over the perforated upper side of the vacuum strip, the upper side serving as a guide surface for the embossing film web. When generating a negative pressure in the interior of the vacuum bar, the embossing foil web is sucked in the region of the perforations covered by it on the guide surface or pressed by the prevailing overpressure on the exposed top of the embossing foil web on the guide surface, so that between the moving embossing foil web and the overflowing Top of the vacuum bar sets sliding friction, the strength of which depends on the pressure difference between the interior of the vacuum bar and the environment. By controlling the suction pressure thus the braking effect of the pneumatic film brake is infinitely adjustable. The pneumatic film brake device does not engage the supply roll 134, but rather directly on the stamped foil web already removed from the supply roll. The braking intervention takes place immediately after rolling from the supply roll, ie directly on the reservoir, before reaching the embossing foundation. Due to the direct attack on the unrolled film web, the braking force is independent of the roll diameter and also independent of the film consumption.

In order to avoid that the vacuum strip at those points, which are not covered by a stamping foil web in operation, draws false air, the vacuum bar is divided into individual adjacent zones Z1, Z2, Z3, etc. In the example, 12 zones of equal width are provided, it may be less, for example, between 6 and 11, or more, for example, be provided between 13 and 20 zones. The zones can be individually closed by means of suitable closure devices. For this purpose, in the embodiment mechanical locking devices provided, which are adjustable by means of adjusting screws 215, which are accessible from the top of the embossing foundation and can be operated by means of a tool. Since no mechanically actuated or mechanically adjustable elements are required to generate the braking force, the braking force of the film brake device can be changed by adjusting the effective negative pressure while the machine is running. For this purpose, for example, be provided within the pneumatic control, a central valve.

In the embodiment shown, all zones of the film brake device are connected simultaneously to a vacuum generator, with some zones being mechanically closed and thus deactivated. In another embodiment, the negative pressure which can be generated before the individual zones can be set separately for each zone separately from other zones, so that the suction force of the suction strip in the individual zones can be changed individually. For this purpose, for example, one or more venturi nozzles can be provided per zone.

The described pneumatic film brake device can be advantageously used in different types of film embossing machines, in particular in round-flat machines or flat-flat machines. The invention also relates to the use of a squeegee of the type described as a film brake, that is to say a pneumatic film brake device as such.

Claims (14)

1. A film embossing machine with an embossing unit (110), the unit comprising a manoeuverable embossing foundation (130) and an embossing cylinder (140) with horizontal rotary axis disposed above the machine bed as a counter pressure element, and with a film unit (180) including control devices for transfer of at least one embossing film web (170) through an embossing gap (145) formed during an embossing interval between the embossing foundation and the counter pressure element, wherein the film embossing machine has a film supply container (136) adapted to retain at least one supply roll (134) fixed on a front face of the embossing foundation and movable in reciprocating motion together with the embossing foundation, and a film brake device (200) to generate web tension between the supply roll and a first control device (182) of the film unit immediately successive to the supply roll, characterized in that
   the film brake device (200) is configured for producing a brake force acting directly on the embossing film web and spaced from the supply roll (134), wherein a component assembly (210) of the film brake device (200) effective in braking is arranged between a roll retainer of the film supply container (136) immediately provided to retain supply rolls and the embossing foundation (130).
2. The film embossing machine according to claim 1, wherein the film brake device is a pneumatic film brake device (200).
3. The film embossing machine according to claim 2, wherein the film brake device has at least one perforated film guiding device (210) including a front face designed as a guiding surface for embossing film webs, the surface including in a utilization zone a plurality of perforations (211) penetrating to the rear face of the film guiding device, wherein the rear face is connected or connectable to a low pressure generator (220).
4. The film embossing machine according to any one of the preceding claims, wherein the film brake device (200) has a total nominal width measured transverse to the extensional direction of the embossing film web and is divided into a plurality of individually adjustable zones (Z1, Z2, Z3) over the total nominal width.
5. The film embossing machine according to claim 4, wherein the braking force of the film brake device in the individual zones (Z1, Z2, Z3) is adjustable individually and independently of other zones.
6. The film embossing machine according to any one of the preceding claims, wherein in addition to the film brake device acting on the embossing film web at least one roll brake device is provided acting directly on a supply roll.
7. The film embossing machine according to any one of the preceding claims, wherein the first control device (182) of the film unit immediately successive to the film supply is a deflection device mounted frame-fixedly relative to the machine bed (120).
8. The film embossing machine according to any one of the preceding claims, wherein the first control device (182) of the film unit immediately successive to the film supply is an air bar.
9. The film embossing machine according to any one of the preceding claims, wherein a second control device (183) of the film unit (180) immediately successive to the first control device (182) is arranged at a large distance above the plane of the first control device (182), wherein a vertical distance between the planes of the first control device and the second control device is preferably more than 40 cm.
10. The film embossing machine according to any one of the preceding claims, wherein the film unit has an advancement system (189) mounted frame-fixedly relative to the machine bed including at least one cycling roller (186) controllable in view of the rotational speed thereof, wherein the advancement system is arranged above the movement plane of the embossing foundation (130) preferably at a distance of at least 40 cm.
11. The film embossing machine according to any one of the preceding claims, wherein the film unit has a film storage device (184) of variable storage length for compensation between a discontinuous movement of the embossing film web in the vicinity of the embossing gap (145) and removal of the embossing film web, wherein the film storage device is mounted frame-fixedly preferably between the first control device (182) of the film unit and the advancement system (189).
12. The film embossing machine according to claim 11, wherein the film storage device takes the form of a horizontal storage device (184), wherein the direction in which the effective storage length of the film storage device is variable during use, is oriented essentially horizontally.
13. The film embossing machine according to claim 11 or 12, wherein the film storage device (184) is arranged at a distance of at least 40 cm above the movement plane of the embossing foundation (130).
14. The film embossing machine according to any one of the claims 11 to 13, wherein the film storage device (184) comprises a dancing roller system of rollers adapted to be moved towards and away from one another in groups, and film strap sections being guided between the rollers.

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