EP0858888B2 - Flat-bed blocking press - Google Patents

Description

The invention relates to a flat embossing machine for a flat material to be embossed with a flat press, embossing table and tool plate according to the preamble of claim 1. In such machines, which embossing tasks particularly demanding quality executable, the embossing foil webs during the stamping phase on the embossing table exactly be held still and then be advanced during the unpressurized phase quickly in the next embossing position of the film web. The delicate stamping foil webs must be treated and promoted gently. This is difficult to achieve, because due to this embossing cycle results in a very uneven feed at the embossing, while the sluggish unwinding be driven substantially uniformly. The resulting changes in length of the film web were previously compensated by dancer rollers. This was possible up to medium embossing speeds, although the film web speeds, the number of simultaneously processable film webs and, above all, the machine speed are limited. On the other hand, however, the flat-flat embossing geometry enables the highest stamping qualities, above all for relief printing and for large image formats. An improvement in subregions could e.g. can be achieved with a register control according to EP-A-708 046 or with an automatic pressure control according to EP-A-741 001. However, the basic restrictions remained.

A completely different type of machine, embossing machines with at least one embossing cylinder, with a baptismal store is known from GB 2 254 586. Here, a film web is pulled by a continuously running unwinding roll via a loop storage gradually through the embossing gap, wherein in the loop memory with the support of an air flow, a free-hanging film loop is formed to compensate for film web length changes. However, these known rotary embossing machines are very limited in terms of stamping quality and machine speed and, above all, the requirements for the film guide according to the relatively low speed differences, however, are relatively low. This in contrast to flat embossing machines with very high speed changes of the film web at the embossing site in a short time, according to their very different embossing cycle. This simple film guide with loop memory according to GB 2 254 586 is therefore generally not applicable to flat embossing machines, especially not for narrow film strips, since the freely hanging film loop in the loop memory is unstable in a stream of air and flutters.

It is therefore an object of the present invention to provide a flat embossing machine which allows best embossing quality even at very high machine speeds and which can be used for a broader range of possible embossing tasks with many film webs and complex images. Above all, a gentle and rapid promotion of several completely different film webs must be possible.

This object is achieved according to the invention by a flat embossing machine according to claim 1. The film loop storage with a differential printing device for length compensation loops of the film web quickly, gently and formed in a compact space, while the film feeding device with the associated feed and loop memory control optimal positioning on Ensures embossing place. The dependent claims relate to advantageous developments of the invention. They concern further improvements of the embossing machine functions and properties, and allow an even wider range of applications. Particularly advantageous combinations result in the additional adjustment of toggle geometry and embossing time and pressure control of the press and register control of the flat material to be embossed.

Fig. 1

eine erfindungsgemässe Flach-Prägedruckmaschine mit Folienbahnspeichern und Vorschubsteuerung

Fig. 2

ein weiteres Beispiel mit Doppelspeichern und Endlosbahn

Fig. 3

ein Schaltschema mit Folienbahn- und Speichersteuerung sowie mit weiteren Funktionen

Fig. 4

den zeitlichen Verlauf von Folienvorschub S und Schlaufenbildung L im Speicher

Fig. 5, 6

Beispiele von Folienschlaufenspeichern mit Führungswänden und Differenzdruckvorrichtungen

Fig. 7

einen Folienspeicher mit einstellbaren Seitenwänden

Fig. 8, 9

Saugkastenspeicher mit variablen Abdeckungen

Fig. 10

einen Speicher mit Saugwalze

Fig. 11

einen Speicher mit Saugwandelement und Lochband

Fig. 12

einen Doppelspeicher mit Saugwandelement

Fig. 13

einen Doppelspeicher mit mehreren Folienbahnen

Fig. 14

eine Maschine mit mehreren unabhängigen Längs- und Querfolienbahnen

Fig. 15

ein Prägebeispiel mit mehreren Prägefolienbahnen und Clichés

Fig. 16

eine Geometrieverstellung von Gelenken einer Kniehebelpresse

Fig. 17

schematisch eine Geometrieverstellung von Kniehebeln

Fig. 18

Hubbewegungsverläufe H des Prägetischs in Funktion der Zeit

Fig. 19 a,b,c

Beispiele von strukturierten Führungsflächen

Fig. 20

eine strukturierte Einlaufwand mit Einblasöffnungen

Fig. 21

eine belüftete Einlaufwand

Fig.22

eine Einlaufwand mit angelegtem Potential

Fig. 23

Doppelfachspeicher mit belüfteten Einlaufwänden

Fig. 24

eine Registereinzugsvorrichtung in einer Bogenmaschine

Fig. 25

eine Endlosbahnmaschine mit Registersteuerung

In the following the invention with reference to examples and figures will be further explained. Show it:

Fig. 1

a flat embossing machine according to the invention with film web stores and feed control

Fig. 2

another example with double storage and continuous web

Fig. 3

a circuit diagram with film web and memory control and with other features

Fig. 4

the time course of film advance S and looping L in memory

Fig. 5, 6

Examples of foil loop stores with guide walls and differential pressure devices

Fig. 7

a foil store with adjustable side walls

Fig. 8, 9

Suction box storage with variable covers

Fig. 10

a memory with suction roll

Fig. 11

a memory with suction wall element and perforated tape

Fig. 12

a double reservoir with suction wall element

Fig. 13

a double storage with several foil webs

Fig. 14

a machine with several independent longitudinal and transverse film webs

Fig. 15

a stamping example with several embossed foil webs and clichés

Fig. 16

a geometry adjustment of joints of a toggle press

Fig. 17

schematically a geometry adjustment of toggle levers

Fig. 18

Stroke curves H of the embossing table as a function of time

Fig. 19 a, b, c

Examples of structured guidance surfaces

Fig. 20

a structured inlet wall with injection openings

Fig. 21

a ventilated inlet wall

Figure 22

an inlet wall with potential applied

Fig. 23

Double compartment storage with ventilated inlet walls

Fig. 24

a register feeder in a sheetfed machine

Fig. 25

an endless web machine with register control

1 shows a flat embossing machine according to the invention for a flat material 5 to be embossed, with a flat-flat press 2, with an embossing table 3 and as a counterpart a tool plate 4 with clichés 23 as well as with at least one stamping foil web 6. The flat material 5 to be embossed consists in this example of sheet 5.1, which led from a feeder 71 via a register device 70 to the flat embossing table 3, stamped there at a standstill and then stacked in a boom 72. The press is a toggle press 41 with four toggle lever pairs 43, with joints 44 and 45 and two pairs of tie rods 42. The tool plate 4 is adjustable in the Z direction by means of a positioning device 61, e.g. with a motor-driven spindle, which adjusts a sliding wedge. The embossing material is on one or more film webs 6, 6.1, 6.2 of unwinding rollers 7, 7.1, 7.2 via a first, the press upstream film loop storage 10 and a film feed device 24 on one side of the embossing table 3 and a clamping device 25 on the other side of the embossing table conveyed and then fed to a Folienabführeinrichtung 8. In this case, the film web 6 can be guided via a second, downstream of the press film loop storage 20 on one or more take-up rollers 80. Instead of take-up rolls 80, a direct film discharge device 81, e.g. in the form of a compactor or shredder system, be used. With the film feed device 24 is a precisely controllable slip-free feed of the film web 6, e.g. by means of light rollers or suction elements, ensured while the clamping device 25 generates an adjustable optimum, uniform film tension on the embossing table, so that the film is held at the embossing position accurate, smooth and without distortion and overstretching for embossing at a standstill. Advantageously, the film feed device 24 is connected downstream of the press and the tensioning device 25, e.g. as a precisely adjustable slip brake with constant braking force or Follenspannung, the press upstream. Conversely, it is also possible to exert a uniform tension on the film web with a downstream tensioning device 25, which is controlled by an upstream film feeding device in a precise and slip-free manner (for example in FIG. 14).

The flat embossing machine has a Folienvorschub- and memory controller 52 with associated operating and display device 40. Thus, the Follenvorschub is controlled according to the flat press cycle at the embossing, wherein the film web is held stationary during the printing phase TP on the embossing table 3 and is preferred during the unpressurized phase TL in the next embossing position, with cycle time T0 = TP + TL, and wherein speed differences between Feed rate VV (t) at the embossing site and web speed V7 at the unwinding or Abführgeschwindigkeit V8 be compensated by corresponding enlargement and reduction of the loops L1, L2 in the film stores 10, 20. This feed control W (t) must be as gentle, precise and fast as possible, so that the film web 6 is held in positional accuracy during the printing phase TP (see FIG. 4) on the embossing table 3 and then rapidly and yet gently into the next during the unpressurized phase TL Prägeposition is preferred. As will be explained further in the examples of FIG. 4, this results in large, rapidly changing speed differences between the relatively constant unwinding or winding speeds V7, V8 on the one hand and the intermittently extending feed speed VV (t). With the film loop stores 10, 20 these differences are compensated by enlargement or reduction of the loops 12 in the stores. For this purpose, the memory with a differential pressure device 30 are connected, which exerts an air pressure difference in the memory 12 on the loops 12 and thus keeps these loops always smooth and stretched.

• eine Steuerung der Kniehebelgeometrie 54 und eine Pressen-Drucksteuerung 56, wie dies in den Figuren 16 bis 18 weiter erläutert wird,
• sowie eine Registersteuerung 58 für Bogen gemäss Fig. 24, bzw. eine Registersteuerung 59 für Endlosbahnen gemäss Fig. 25.

In addition to the machine controller 50 with film and memory controller 52, further advantageous combinations for control functions can be integrated (see FIG. 3):

• a control of the toggle geometry 54 and a press-pressure control 56, as further explained in FIGS. 16 to 18,
• and a register control 58 for sheets according to FIG. 24, or a register controller 59 for continuous webs according to FIG. 25.

FIG. 2 shows, as a further example, a flat embossing machine with an endless web 5.2 as a flat material 5 to be embossed with a dancer roller store 110, wherein here the flat material and the film web 6 are conveyed in the opposite direction, while FIG. 1 shows the synchronization of flat material 5, which is advantageous in many cases and film web 6 illustrated. The foil side Velocity ratios with respect to VV, V7, V8 also remain the same as described for FIG. The two film loop stores 10 and 20 are designed as double labyrinth store 28 with a common internal suction as differential pressure device 30. This represents a particularly simple and compact design of a double memory. For measuring and monitoring the loop depth LT and thus also the loop length L in the storage serve film loop sensors SF (see Fig. 6).

FIG. 3 shows a circuit diagram with a machine control 50, a film web and storage controller 52, a control of the toggle geometry 54, a pressure control 56 and a register control 58 for sheetfed or endless web machines 59, as well as associated sensors SF, SB, SP and SD and with an operating and display device 40 for the relevant setting and control functions. The example illustrates the controls of a machine with two independently controllable film webs 6.1, 6.2 with Abwikkelrollen 7.1, 7.2 or take-up rollers 80.1, 80.2 and associated sensors for determining the Abwikkelgeschwindigkeit V7.1, V7.2 and the take-up speed V8.1, V8. 2 (eg determined from roller diameter and speed). The corresponding feed rates VV1, VV2 are also determined on the film feed devices 24.1, 24.2 (for example by means of encoders on servomotors). With the film clamping devices 25.1, 25.2 optimal film clamping forces FF1, FF2 are directly or indirectly adjustable and controllable. These foil clamping forces FF1, FF2 are tunable to the relevant film web and the selected embossing process that the embossing foils are promoted on the one hand as gently as possible and without overstretching and yet an accurate, straight alignment and positioning of the films is achieved at the embossing site 3 while this and during the Embossing process is optimally adjustable.

An additional film-like alignment of the film webs 6 on the clichés 23 of the tool plate 4 can be carried out by means of film image sensors SB1, SB2 (see FIGS. 2 and 15a). This is e.g. necessary for embossing holograms or foil images which are to be positioned in register on the clichés (and from the other side the flat material is positioned with respect to the clichés with the register device). With the film and memory controller 52, the loop formations in the two memories 10 and 20 are also controlled and monitored, e.g. by film web sensors SF1.1, SF1.2 in the memory 10 and the sensors SF2.1, SF2.2 in the memory 20, which each detect the loop depths LT1.1, LT1.2 and LT2.1, LT2.2. As advantageous combinations with this film web and storage controller 52, control of the toggle geometry 54, e.g. by adjusting the distance XS of the toggle lever check points and thus influencing the embossing time DT, as well as a control 56 of the pressure force via the positioning device 61 of the press with the aid of pressure force sensors SP1 to SP4 (FIG. 1). A register control 58 for sheetfed machines with sensors SDi and actuators 91, 92, 93 (of FIG. 1, 19) or register control 59 for endless web machines with web stores 110, 120, web edge controls 112, 113 and web advance and web tensioners 124, 125 also provides an advantageous combination.

Figure 4 illustrates, in an example with a five-cycle period, the feed control VV, the film advance S (t) and the looping L (t) in the storages as a function of time over several imprinting cycles. In this case, a relatively small film advance (of, for example, 7 cm each) takes place over four cycles, followed by a large advance in the fifth cycle (by, for example, 77 cm).

FIG. 4a shows the progression of belt conveyance S7 (t) at a web speed V7 (t) = dS7 / dt at the unwinding roller 7 and the feed S (t) at feed speed VV (t) = dS / dt at the embossment location over several periods every five cycles. From the difference between V7 and VV results in a varying loop length L (t) = S7 (t) -S (t), which has a minimum L1 and a maximum L2 of the loop length in the memories.

FIG. 4b shows this course over the cycles 4, 5 and 1 in more detail. The feed rate S (t) is controlled as balanced as possible without large changes in speed, ie with the lowest possible accelerations (d2S / dt ² ). This is especially important in the fifth cycle, when large changes in loop length (from L2 to L1) occur in a short time during the unpressurized phase TL of the cycle. As can be seen, during the printing phase TP and in particular during the embossing time DT, the feed S (t) must be = 0, ie the film web must rest precisely on the embossing table. The line S7.2 (t) shows by way of example also a different time profile for a second film web 6.2, which here has a higher unwinding speed V7.2.

FIG. 4c shows the time variation of the loop length L (t) in the film loop store 10 in accordance with the feed movement S (t) according to FIG. 4b.

FIG. 4d shows an enlarged view of the feed S (t) in the cycle 5 and the influence of the adjustment of the embossing time DT and thus also of the pressure phase TP by a toggle lever adjustment according to FIGS. 16-18. A short embossing time DT1 results in a small value of TP1 and remains correspondingly a larger range TL1 for the change of the feed rate VV and for the change of the loop length L in the memories. With a large embossing time DT2 and correspondingly greater value of TP2, a smaller value of TL2 results, which is available for the film feed, in accordance with the relationship T0 = TL2 + TP2. Especially at the desired very high embossing speeds of eg 10'000 cycles per hour and more Both the cycle duration T0 and correspondingly the phases TP and TL are very small, which requires correspondingly higher feed rates during the unpressurized phase TL.

FIG. 5 shows a film loop storage 10 with two guide walls 16, 17, deflection rollers 39 and with a controllable pressure fan 31 and / or a suction fan 32 as a differential pressure device. These generate a differential pressure DP = P1 - P2 (with P1 = pressure in the loop, P2 = pressure outside or before the loop) and thus an adjustable air flow, which extends substantially in the direction of extension of the loop 12 in the film memory. The film loop 12 runs along the guide walls 16, 17 and parallel to these.

As shown in Figure 6, the guide walls 16, 17 may be e.g. also conical, wherein the arrangement of guide walls (as well as any side walls) and differential pressure devices is coordinated so that a uniform air flow for optimum formation of the desired film loop in the entire range between minimum loop length L1 and maximum loop length L2 arises. The determination and monitoring of the loop length L takes place here with a distance sensor SF (for example as an optical or ultrasound detector), which is arranged at the memory input and measures the loop depth LT. From LT then the loop length L can be calculated.

Figures 7a, b show a film loop storage with side walls 18, 19 from above and from the side. The example shows a further variant of an adjustable storage geometry, with which, matched to the differential pressure device, an optimal local flow distribution for proper loop formation, for example, of different widths film webs can be adjusted. With adjustable side walls 18, 19 or attached lids 22 adjustable openings or slots 13 may be formed. These settings of geometry and openings of the memory 10 can also be made controllable automatically by means of actuators or by the controller 52.

As another example, the film loop store according to FIG. 8 has a suction box 15 with an inlet opening 14 for the film webs 6.1, 6.2 and with a suction fan 32 at the loop end or at the lower end of the suction box.

Figure 9a, b shows from above and from the side of a Saugkastenspeicher 15 with variable covers 26 at the inlet opening 14. The loop memory can simultaneously record a plurality of film webs 6.1, 6.2 (different type and width), which are supported independently and thus form different loops , In order to achieve optimum flow conditions for each loop, it is possible with the variable coverings 26 to set each film web 6.1, 6.2 to approximately equal size free inlet openings 27 on both sides.

As illustrated in FIGS. 10 to 12, the differential pressure devices of the film loop stores can also have suction rolls 34 or suction wall elements 35 with circumferential perforated belts 36, which are advantageously additionally combined with a pressure or suction fan 31, 32.

FIG. 10 shows on the input side a suction roll 34 with a suction region 37 for conveying the film web 6 into the store. The loop formation is still supported by a pressure blower 31.

In FIG. 11, a perforated suction wall element 35 with a circumferential perforated belt 36 via the suction and conveying region 37 conveys the film web 6 to form a loop in the store. This memory is suitable e.g. especially good for long loops with very narrow foil webs.

FIG. 12 shows a suction wall element 35 with perforated belt 36, the downwardly running region 35. 1 of which forms a transport wall of a supply reservoir 10 and whose upwardly running region 35. 2 forms a transport wall for a discharge reservoir 20.

FIG. 13 shows a double memory 29, which has two compartments 16.1, 17.1 and 16.2, 17.2, wherein these two compartments have a plurality of film webs 6.1 to 6.4 alternately and each spaced apart on the compartments. Both compartments can be operated together with only one differential pressure device.

Figure 14 illustrates an example of a machine having a plurality of longitudinal and transverse film webs (in the X and Y directions) which are individually independently controllable. Two longitudinal webs 6.1 and 6.2 with feed speeds VV1, VV2 have separate feed devices 24.1, 24.2 and clamping devices 25.1, 25.2 and common film loop stores 10.1, 20.1. Two transverse tracks 6.3, 6.4 with feed speeds VV3, VV4 have separate feed devices 24.3, 24.4 and clamping devices 25.3, 25.4 and common foil stores 10.2 and 20.2.

FIG. 15 illustrates an embossing work with several different embossing foil webs with different embossing material and different clichés, which is carried out simultaneously in an embossing process. The arrangement of the film webs in the longitudinal and transverse direction can be coined simultaneously with more clichés and more complex images. Condition is that no clichés are arranged in the crossing regions of the film webs. As a simple example, in FIG. 15a a sheet 5.1 to be marked is subdivided in the Y-direction into two identical areas. In the X direction, two identical film webs 6.1, 6.2 are embossed with image units corresponding to the clichés 23.1. The registration of these film-forming units with respect to the clichés 23.1 and thus also with respect to the sheet to be embossed 5.1 by film image sensors SB1, SB2 (which film image marks detect) monitored and controlled. In the Y direction, two film webs 6.3, 6.4 run with different color layers as embossed goods and with associated clichés 23.2, 23.3.

FIG. 15b shows the pronounced image film web 6.2 and in FIG. 15c the pronounced color film web 6.3 with a 3-cycle period. The arrangement of the film webs and their individual feed control is done so that the Folienprägegut is used optimally possible. With the inventive combination of compact, very responsive common loop memories for multiple and independently controllable film webs a flat-embossing machine is created, which can perform very demanding and complex embossing tasks in a single pass at high speed and in the best quality and in addition, the film webs little burden and whose stamped good can be utilized to the best extent possible.

FIGS. 16 to 18 illustrate the combination of the machine according to the invention with a geometry adjustment or a stamping time adjustment (DT). Thus, optimization is possible in two dimensions, i. by means of two independent adjustment variables: both with regard to the film advance S (t) and with respect to the embossing process with the embossing time DT. This results in maximum embossing quality and universal application possibilities. FIG. 16 shows, seen from above, a geometry adjustment of a toggle press with four toggle lever pairs, the lower four toggle joints 45 (see FIG. 1) being simultaneously adjusted by a servo drive 48 via a transmission to the four joints 45. each via a spindle and a Verstellkeil 49, so that the distance XS of the joints 45 is adjustable by means of the controllable motors 48 and a geometry controller 54. But there are also other forms of drive (eg hydraulically or manually) or all four Joints 45 are moved directly with one synchronously controlled motor. The adjustment can be programmable and preferably takes place stepwise only during the depressurized phase (TL).

FIG. 17 illustrates the geometry adjustment on one of the toggle lever pairs 43, which are moved by the tie rods 42. Depending on the setting XS of the lower joints 45 result different courses of Hubmaxima H (t) of the press as shown in three examples of settings below.
The setting XS1 <0 results in a maximum deflection position 43a, whereby the toggle levers 43, 43a do not quite reach their stretched position 46.
With the setting XS2 = 0, the stretched layer 46 is just reached in the maximum deflection position 43b. With the setting XS3> 0, the stretched layer 46 is exceeded until the maximum deflection 43c. This yields after

1. a) Für XS1 < 0 (z.B. -3 mm) resultiert die Kurve H1 (t) mit schmalem Maximum, für eine gegebene Höhendifferenz DH ergibt dies eine Prägezeit DT1 von z.B. 25°.
2. b) Für XS2 = 0 resultiert die Kurve H2(t) mit einem breiteren Maximum und für das gegebene DH eine grössere Prägezeit DT2 von z.B. 35°.
3. c) Für XS3 > 0 (z.B. + 1 mm) resultiert eine Kurve H3(t) mit zwei Maxima Hmax und für das gegebene DH eine entsprechend noch grössere Prägezeit DT3 von z.B. 42°.

FIGS. 18 a, b show the following courses of motion of the stroke H (t) of the press as a function of time:

1. a) For XS1 <0 (eg -3 mm) the curve H1 (t) results with a narrow maximum, for a given height difference DH this results in an embossing time DT1 of eg 25 °.
2. b) For XS2 = 0, the curve H2 (t) results in a wider maximum and for the given DH a longer imprinting time DT2 of, for example, 35 °.
3. c) For XS3> 0 (eg + 1 mm) a curve H3 (t) with two maxima Hmax results and for the given DH a correspondingly even longer stamping time DT3 of eg 42 °.

The height difference DH results from how strong a given flat material 5 to be embossed is compressible. This also results in the stroke of the movement H (t) corresponding course of the pressing force F (t). If in case a) the stretched layer 46 is not fully reached, the tool plate 4 must be readjusted by means of positioning device 61 in the direction Z4, in order to compensate for the missing height H. As shown in Figures 18a, b, the printing phase TP is necessarily slightly larger than the stamping time DT. This can be used for cases a, b, c e.g. TP1 = 40 °, TP2 = 50 °, TP3 = 60 °. Correspondingly, the pressureless phase TL changes according to the relationship T0 = 360 ° = TP + TL (see FIG. 4d).

Another particularly advantageous combination results from the integration of a pressure control in the machine, as is known from EP-A-749 001. For this purpose, the embossing machine has sensors SP1 to SP4 for measuring the press compressive forces F (see FIGS. 1 and 16). The pressure control 56 controls by the positioning device 61, the tool plate 4 in the direction Z4, so that a desired predetermined working pressure F can be automatically kept constant. The print controller may also include various press force control functions. With the toggle lever geometry control 54 and the press-pressure control 56, optimum parameter values can thus be set both with regard to the embossing time DT and with respect to the embossing pressure force F, thereby achieving the highest embossing quality and machine performance. This control of the knee lifting geometry and the printing phase can also be used independently of the loop memories according to the invention for optimizing the embossing quality.

In the inventive machine films of different types and widths should be optimally processed. In particular, very wide and very thin films with a thickness of eg 15 - 30 μ are extremely difficult to transport properly. The insulating plastic carrier material of the films is charged electrostatically, which may result in relatively high frictional forces on the guide walls (inlet walls 16 and outlet walls 17) of the reservoir, which can lead to distortion and hull formation of the film webs. An important further education The invention consists in keeping the frictional forces of the foil webs running over it, especially at the inlet walls 16 of the loop store, small or reducing them to an extent that the loop formation and transport can take place optimally. Various measures and means for this will be illustrated with reference to FIGS. 19 to 23.

Figures 19 and 20 illustrate textured surfaces 63 on the guide walls 16, 17, the contact surface F1 thereof with the overlying foil being substantially smaller than the entire foil covered surface F0. The ratio of contacted to covered area F1 / F0 is less than 50% and is preferably even less, e.g. 10 - 30%.

Such structured surfaces 63 can be formed in various ways, e.g. by grooves or channels 64, according to FIG. 19 a and FIG. 20, or by grids, or fine-meshed wire mesh 65 according to FIG. 91 b or by perforated sheets, dimpled sheets or corrugated sheet metal 66 according to FIG. The lattice constants or pitches of these patterned surfaces are preferably only 1 mm or less, e.g. 0.3-1 mm.

FIG. 20 shows in plan view an example of a structured surface with longitudinal and transverse channels 64, an area ratio F1 / F0 of approximately 25% being illustrated here.

Another particularly simple and effective method for reducing the Kontakflächenanteils F1 or the frictional force of the film web on the inlet wall 16 is to partially detach the film web by partial injection of air from the inlet wall. This is illustrated in FIG. 21. The inlet wall 16 has injection holes 75, through which from a pressure chamber 74 locally air is blown under the film. This air-assisted reduction of the friction force at the inlet wall is, according to the films to be transported, easily metered by means of controlling the overpressure P3 in the chambers 74. This may e.g. 2-4 bar amount. The blow-off openings 75 are preferably relatively small dimesioniert and arranged at great distances from each other. The diameter of the blow-off openings is e.g. 1 mm or less and the distances are several cm, e.g. 5-20 cm. It is important that the film always remains on the guide wall and is not completely lifted, i. the contact surface portion F1 is not 0. This ensures a smooth, perfect guidance of the film web. The guide walls are metallically conductive and the ventilated inlet walls can have a smooth surface (FIG. 21) or a structured surface (FIG. 20).

Fig. 22 shows a further variant for reducing the frictional force by applying a potential U2 to the inlet wall 16 with an adjustable voltage source 96. The inlet wall is metallically conductive and formed isolated from the environment. Thus, the potential difference U1 - U2 between the film web 6 and the guide wall 16 is reduced so much that the desired low value of the frictional force is achieved. The setting of the potential U2 at the inlet wall 16 is such that an optimal smooth looping and film guide is achieved. In addition, the potential U1 of the film web 6 can be determined by means of a capacitive potential probe 95 and then the potential U2 can be adjusted or regulated.

Fig. 23 shows an example, each with a double-pocket memory 29 before and after the embossing press and each with a film web 6.1, 6.2 in a respective compartment of these two double-pocket memory. The loop formation in the reservoirs takes place by vacuum suction by means of a common exhaust fan 32. The four inlet walls 16. 1, 16. 2 have a ventilation with overpressure chambers 74 with a pressure P 3 and injection openings 75. However, the four outlet walls 17.1, 17.2 are expressly not ventilated. The friction force at the outlet walls is intentionally higher than at the inlet walls, so that the film web is slightly stretched for the purpose of further transport. A trailing wheel 53 with encoder detects here speed and feed of the running film web, whereby the motor of the take-up roll 80 and feed and looping are controlled in the memories.

FIG. 24 shows the combination of the flat embossing machine according to the invention with a register control 58 of the flat material. This combination allows a two-sided optimization both film web side with respect to the film guide and alignment as well as with respect to the flat material guide for accurate image alignment. On the film side, e.g. Foliensujets such as holograms or foil images by means of the film image sensors SB (Fig. 15a, Fig. 2) with respect to the clichés 23 on the tool plate 4 exactly aligned, while the sheets are also aligned by the 5.1 register position accurate to the position of the clichés. Such register control for sheetfed presses is known from EP-A-708 046.

The indexing machine 70 for flat embossing machines has front edge stops, a side stop and position sensors SD1, SD2, SD3 for detecting print marks M1, M2, M3 of the sheet 5.1 and two detectors SD4, SD5 associated with the front stops A1, A2 for detecting the sheet leading edge. The front stops A1, A2 are adjustable so far by actuators 91, 92 until the front print marks M1, M2 of the sheet are detected by the corresponding sensors SD1, SD2. An actuator 93 then adjusts the side stop or side shift A3 until the side print mark M3 is detected by the assigned position sensor SD3. A register controller 58 controls this register correction with the position sensors SD1, SD2, SD3, the detectors SD4, SD5, and the actuators 91, 92, 93. This easily provides a reliable automatic register correction for each individual sheet and thus increases in combination with me the film guide and control the print quality.

FIG. 25 shows schematically from above a register control 59 for endless web machines (FIG. 2) with sensors SD1, SD3 for detecting print marks M1, M3. The endless web 5.2 runs from a supply reel 107 to a take-up reel 108 with web edge controls 112, 113, web stores 110, 120 (designed as dancer rolls or also as a suction store), a web tensioning device 125 and a web feed device 124. The alignment of the endless web in the transverse direction Y onto the print mark M3 is performed by the rail edge controls 112, 113 known per se, and the alignment with the mark M1 in the longitudinal direction X is controlled by the web feed device 124. To compensate for the differences between the intermittent feed on the embossing table 3 and a uniform unwinding speed on the rollers 107, 108, web stores 110 and 120 for the continuous web 5.2 are also used here in an analogous manner to the film web control.

2

Flach-Presse

3

Prägetisch

4

Werkzeugplatte

5

Flachmaterial

5.1

Bogen

5.2

Endlosbahn

6

Folienbahnen

7

Abwickelrolle

8

Folienabführeinrichtung

10, 20

Folienschlaufenspeicher

12

Folienschlaufe

13

einstellbare Öffnungen an 18, 19

14

Eingangsöffnung

15

Saugkasten

16

Einlaufwand

17

Auslaufwand

16,

17 Führungswände

18,

19 Seitenwände

22

Deckel an 18, 19

23

Clichés

24

Folienvorschubeinrichtung

25

Spanneinrichtung

26

Variable Abdeckungen an 14

27

freie Einlassöffnungen an 14

28

Doppelschlaufenspeicher Labyrinth

29

Doppelfach

30

Differenzdruckvorrichtung

31

Druckgebläse

32

Sauggebläse

34

Saugwalze

35

Saugwandelement

35.1

aufwärts

35.2

abwärts laufend

36

Lochband

37

Saugbereich von 34, 35

39

Umlenkrollen

40

Bedienungs- und Anzeigegerät

41

Kniehebelpresse

42

Zugstangen

43

Kniehebel

44

Kniegelenke

45

untere Kniehebelgelenke

46

Verbindungsgerade, gestreckte Lage

48

steuerbare Motoren

49

Verschiebekeil

50

Maschinensteuerung

52

Steuerung Folienvorschub und Speicher

53

Schlepprad

54

Steuerung Kniehebelgeometrie

56

Drucksteuerung

58

Registersteuerung für Bogen

59

Registersteuerung für Endlosbahn

61

Positioniervorrichtung bei 4

63

strukturierte Oberfläche

64

Kanäle

65

Gitter, Drahtgeflecht

66

Wellblech

70

Registervorrichtung für Bogen 5.1

71

Anleger

72

Ausleger

74

Überdruckkammer

75

Einblasöffnung

80

Aufwickelrolle

81

direkt abführen

91, 92, 93

Stellglieder

95

kapazitive Potentialsonde

96

einstellbare Spannungsquelle

107

Abwicklung Endlosbahn

108

Aufwicklung Endlosbahn

110, 120

Bahnspeicher

112, 113

Bahnkantensteuerung

124

Bahnvorschubeinrichtung

125

Bahnspanneinrichtung

T0

Pressenzyklus, Zyklendauer

TP

Druckphase

TL

drucklose Phase

DP = P1 - P2

Druckdifferenz

P1

Druck in Schlaufe 12

P2

Druck vor Schlaufe 12

P3

Druck in Überdruckkammern

VV

Vorschubgeschwindigkeit

V7

Bahngeschwindigkeit an 7

V8

Bahngeschwindigkeit an 8

S(t)

Folienvorschub

L

Schlaufenlänge

L1

Schlaufenlänge in 10, Minimum

L2

Maximum

LT

Schlaufentiefe

DT

Prägezeit

DH

Höhendifferenz während DT

H(t)

Höhe von 3

XS

Verschiebung von 45

M1, M2, M3

Druckmarken

SD1 - SD5

Registersensoren, Lagedetektoren

A1, A2

Vorderanschläge

A3

Seitenanschlag

X

Laufrichtung

Y

Querrichtung

Z

Hochrichtung

Z4

Verschiebung von 4

F

Druckkräfte

t

Zeit

SF

Sensoren für Folienschlaufe

SB

Folienbildsensoren

SP

Druckkraftsensoren

FF

Folienspannkräfte

F1

Folienkontaktfläche

F0

überdeckte Folienfläche

F1/F0

Kontaktflächenanteil

The following terms are used in connection with the figures:

2

Flat-Presse

3

embossing table

4

tool plate

5

flat material

5.1

bow

5.2

continuous web

6

film webs

7

unwinding

8th

Folienabführeinrichtung

10, 20

Foil loop store

12

foil loop

13

adjustable openings at 18, 19

14

entrance opening

15

suction box

16

entry wall

17

outlet wall

16

17 guide walls

18

19 side walls

22

Cover at 18, 19

23

clichés

24

Sheet feeder

25

tensioning device

26

Variable covers on 14

27

free inlet openings at 14

28

Double-loop storage maze

29

double Trade

30

Differential pressure device

31

pressure blower

32

aspirator

34

suction roll

35

suction wall

35.1

up

35.2

running downhill

36

perforated tape

37

Suction area of 34, 35

39

guide rollers

40

Operating and display device

41

Toggle Press

42

drawbars

43

toggle

44

knee Joints

45

lower toggle joints

46

Connecting straight, stretched position

48

controllable motors

49

sliding wedge

50

machine control

52

Control of film feed and storage

53

idler

54

Control of toggle geometry

56

pressure control

58

Register control for sheets

59

Register control for continuous web

61

Positioning device at 4

63

structured surface

64

channels

65

Grid, wire mesh

66

corrugated iron

70

Register device for sheet 5.1

71

investor

72

boom

74

Hyperbaric chamber

75

inflation opening

80

up roll

81

directly dissipate

91, 92, 93

actuators

95

capacitive potential probe

96

adjustable voltage source

107

Processing endless web

108

Winding endless web

110, 120

web store

112, 113

Web guide

124

Bahn feeder

125

Railway clamping device

T0

Press cycle, cycle time

TP

pressure phase

TL

pressureless phase

DP = P1 - P2

pressure difference

P1

Pressure in loop 12

P2

Pressure in front of loop 12

P3

Pressure in overpressure chambers

VV

feed rate

V7

Web speed at 7

V8

Web speed at 8

S (t)

sheet feed

L

strap

L1

Loop length in 10, minimum

L2

maximum

LT

loop depth

DT

embossing time

DH

Height difference during DT

H (t)

Height of 3

XS

Shift of 45

M1, M2, M3

print marks

SD1 - SD5

Register sensors, position detectors

A1, A2

front stops

A3

side stop

X

direction

Y

transversely

Z

vertical direction

Z4

Shift from 4

F

compressive forces

t

Time

SF

Sensors for film loop

SB

Film image sensors

SP

Compression Load Cells

FF

Foil tensioning forces

F1

Film contact surface

F0

covered foil surface

F1 / F0

Contact surface portion

Claims (27)

1. Flat embossing machine for a flat material (5) to be embossed, with a flat press (2), embossing table (3) and tool plate (4) and having at least one embossing foil web (6), which is guided from an unwinding roll (7), via the embossing table to a foil removal device (8), with a foil feed device (24) on one side of the press and a tensioning device (25) for tensioning the embossing foil web (6) on the other side of the press and with a control (52) of foil feed at the embossing location corresponding to the press cycle (T0), with which the embossing foil web is kept stationary on the embossing table (3) during the embossing phase (TP) and during the embossing-free phase (TL) is advanced into the next embossing position and in which speed differences between the speed VV at the embossing location and the web speed V7 at the unwinding roll or at the removal device V8 are compensated,
   characterized by
   at least one foil loop store (10) with a differential pressure device (30) for shaping a foil loop (12) upstream of the press by means of an air pressure difference (DP) exerted on the embossing foil web, whereby the embossing foil web (6) is guided flat and parallel along guide walls (16, 17) with a frictional force between embossing foil web and guide walls, and whereby the control (52) controls the loop formation by a corresponding increase or decrease in size of the loops (L1, L2) in the foil stores (10, 20) for compensation of the speed differences, and whereby during the embossing-free phase (TL) the embossing foil web (6) is continuously accelerated and decelerated and advanced into the next embossing position, i.e. with minimum possible acceleration (d2S/dt²).
2. Flat embossing machine according to claim 1, characterized by a further foil loop store (20) and a wind-up roll (80) following the press as a foil removal device (8).
3. Flat embossing machine according to claim 1 or 2, characterized in that the differential pressure device has a controllable pressure fan (31) and/or suction fan (32), which produce an adjustable air flow, which runs substantially in the extension direction of the loop in the foil store and that the foil loop stores have two guide walls (16, 17) parallel to the foil loop (12).
4. Flat embossing machine according to one of the preceding claims, characterized in that the foil loop stores have an adjustable geometry (13, 26) for modifying the local flow distribution.
5. Flat embossing machine according to claim 3, characterized in that the foil loop stores also have two side walls (18, 19) with adjustable openings (13).
6. Flat embossing machine according to one of the preceding claims, characterized in that the foil loop stores have a suction box (15) with an inlet (14) for the foil web and with a suction device (32) at the loop end.
7. Flat embossing machine according to one of the preceding claims, characterized in that the foil loop stores have an inlet (14) with variable covers (26) and that the foil loop stores on either side of a foil web have substantially equal size, free inlets (27).
8. Flat embossing machine according to one of the preceding claims, characterized in that the foil loop stores have a suction roller (34) or a perforated belt (36) with suction fan (32) as foil transportation means at the store.
9. Flat embossing machine according to one of the preceding claims, characterized in that the foil loop stores have a fixed, perforated suction wall element (35) with a vacuum in the interior, about which runs a perforated belt (36) and consequently brings about a continuous foil transport.
10. Flat embossing machine according to claim 9, characterized in that the perforated belt runs round a bilateral suction wall with in each case an upwardly directed (35.1) and a downwardly directed (35.2) area, which in each case form a guide wall of two adjacent foil stores (10, 20).
11. Flat embossing machine according to one of the preceding claims, characterized by sensors (SF1, SF2) for monitoring loop formation, particularly distance sensors for measuring the loop depth (LT), e.g. in the form of optical or ultrasonic detectors.
12. Flat embossing machine according to one of the preceding claims, characterized in that several foil webs (6.1, 6.2, 6.3) are arranged in juxtaposed manner with gaps in the foil stores and that several foil webs (6.1, 6.2) with separate feed devices (24.1, 24.2) are provided, whose feed (VV1, VV2) is individually controllable.
13. Flat embossing machine according to one of the preceding claims, characterized in that the foil stores are constructed as double loop stores (28, 29) for several foil webs.
14. Flat embossing machine according to one of the preceding claims, characterized in that there are several embossing foil webs (6.1 - 6.4) with associated foil stores along and/or transversely to the flat material running direction X.
15. Flat embossing machine according to one of the preceding claims, characterized in that at least on the entry walls (16) of the loop stores means are provided for reducing the frictional force of a foil web (6) running over the same, so that the frictional force on the entry walls (16) is smaller than the fictional force on the exit walls (17).
16. Flat embossing machine according to one of the preceding claims, characterized in that the contact surface fraction F1 of a foil web on the guide surfaces (16, 17) of the loop stores is less than half the covered foil surface F0, e.g. F1/F0 = 10 to 30%.
17. Flat embossing machine according to claim 16, characterized in that at least the entry walls (16) have a structured surface (63), e.g. in the form of channels (64), fine mesh wire gauzes (65), knobbed plate or corrugated plate (66).
18. Flat embossing machine according to one of the preceding claims, characterized in that on the entry walls (16) air from overpressure chambers (74) is blown through injection openings (75) into the loop stores.
19. Flat embossing machine according to claim 18, characterized in that small injection openings with a relatively large spacing are provided, e.g. with a diameter of 0.5 to 1 mm and with a spacing of 5 to 20 cm.
20. Flat embossing machine according to one of the preceding claims, characterized in that a potential U2 is applied to metallic, conductive entry walls (16) by means of an adjustable voltage source (96).
21. Flat embossing machine according to claim 20, characterized in that a capacitive potential probe (95) is provided for determining the potential U1 of the entering foil web (6) and for the corresponding control of the potential U2 at the entry wall (16).
22. Flat embossing machine according to one of the preceding claims, characterized in that a bent lever press (41) is provided, whose bent lever geometry is adjustable (XS) in such a way that the embossing phase (TP) can be varied.
23. Flat embossing machine according to claim 22, characterized in that the bent lever geometry is adjustable by modifying the spacing (XS) of the bent lever joints (45).
24. Flat embossing machine according to claim 22, characterized in that the adjustment takes place by a control (54) using controllable motors (48), e.g. by servomotors and a shift wedge and that the adjustment is programmable and is performed stepwise during the embossing-free phase (TL) with the machine running.
25. Flat embossing machine according to claim 22, characterized in that simultaneously the position of the tool plate (4) can be adjusted by means of a positioning device (61) through a print control (56) with control program and with pressure sensors (SP).
26. Flat embossing machine according to one of the preceding claims for sheets as flat material, characterized in that a conveying device for sheets (5.1) with feeder and delivery means, as well as with a register draw-in device (70) with a register control (58) and with sensor-controlled front and side stops (A1, A2, A3) is provided for orienting the sheet according to print marks (M1, M2, M3), which are detected by sensors (SD).
27. Flat embossing machine according to one of the claims 1 to 25 for a continuous web as flat material, characterized by a register control (59) for orienting and controlling the continuous web (5.2) according to print marks (M1, M3) by means of sensors (SD1, SD3), the control taking place in the transverse direction through a web edge control (112) and in the longitudinal direction by control of the continuous web feed (124).

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