EP2130686B1 - Pressing device and method for pressing structures onto safety documents - Google Patents

Description

On the one hand, the invention relates to an embossing device for impressing structures on security documents with an embossing head, with an embossing punch and with an embossing boss, wherein in the embossing device the embossing punch can be displaced between the embossing head and the embossing boss. On the other hand, the invention relates to an embossing method for embossing structures on security documents, in which an embossing punch is pressed against an embossing boss and the structures are impressed on the security documents.

Generic embossing devices and embossing methods are frequently used for embossing thermally activatable films on security documents. In particular, such embossing devices are widely known from the prior art. For example, to a related art include embossing machines with an embossing head, in which an embossing die is driven via a toggle mechanism by means of an electric motor, the embossing die opposite to a embossing boss can perform an embossing movement. This is also referred to as path-controlled embossing drives, since the embossing stamp, due to the toggle mechanism, always passes through the same embossing movement, regardless of which thickness a structure to be applied has. This leads to high wear of all components, so that a high embossing number is hardly achievable with such embossing machines, although usually a support plate is provided as a wear part between the die and the embossing boss.

Often components have to be repaired or even changed after just a few impressions. This is very costly and therefore very disadvantageous.

It is also disadvantageous in the known path-controlled embossing drives that an embossing point, in which the actual embossing of a structure on a document is performed, is very difficult to determine with sufficient precision in the case of variously thick structures to be embossed. Since such differences in thickness usually can not be accurately detected, a related Aufprägeprozess is relatively uncontrolled and unsteady, so that is almost always to be expected even with imprints in terms of a single sheet layouts with different embossing qualities of the individual imprints.

EP 0 131 535 A2 discloses an apparatus for marking articles having a head device connected to a support structure and having a counter surface positionable at a predetermined distance from a material surface, and an array of discrete chambers within the head device each having a piston receiving portion extends from an abutment position to a seat surface and is in communication with a shank receiving part which extends from the seat surface to an opening in the counter surface.

It is an object of the invention to further develop generic Aufprägevorrichtungen in particular to turn off the aforementioned disadvantages.

The object of the invention is achieved by an embossing device for embossing structures on security documents with an embossing head, with an embossing punch and with an embossing boss, in which the stamper is displaceable between the embossing head and the embossing boss, wherein the embossing device has a pressure-controlled drive device, by means of which the stamp can be driven by set by a pressure control valve stamping forces. In addition, a pressure switch is arranged to start an embossing time.

Advantageously, by means of the pressure-controlled drive device, an embossing point can be set individually as a function of a structure to be embossed, so that the risk of inferior embossing quality is substantially reduced as a result.

It is particularly advantageous that the embossing punch is not necessarily displaced into a constant embossing position, as is the case with known travel-controlled embossing drives, but the embossing stamper can also be displaced into variable embossing positions with respect to different thicknesses of the objects to be embossed by means of the pressure-controlled drive device. if this is necessary for a good embossing result.

Advantageously, in addition to the embossing position, embossing forces can also be set individually by means of an air pressure of the pressure-controlled drive device.

It is understood that a wide variety of gases can be used as a pneumatic pressure means for operating the pressure-controlled drive device. A particularly cost-effective pressure medium is air, which in the present case is preferably used as compressed air.

It is further understood that the embossing device according to the invention can be used for impressing on a large number of structures.

Preferably, the present embossing device is used for impressing structures / films on documents or in documents. Such documents may be security documents, such as passports, identity cards, cards, etc. These structures include patterns, in particular hologram-like structures, such as holograms, kinegrams, etc., which are applied to thermally activatable films as carrier film and by means of such a carrier film Imprinting be supplied. Thus, the present imprinting device is primarily a precision embossing device for imprinting structures for security documents. Thus, in the present embossing device, a structure to be embossed during the embossing process consists of a security document to which a thermally activatable film having at least one structure is applied. After the embossing process, in which the thermally activatable film is thermally activated by means of a heating device, not shown, the thermally activated or activated film can be removed from the security document to which the structure (s) is impressed. The thermally activatable film thus serves as a carrier film for the aufzuprägende structure (s).

In particular, when imprinting on security documents special materials are used, so that predetermined process parameters must be met very accurately. This can advantageously be ensured structurally particularly simple with the present embossing device.

The pressure controlled drive means may comprise a pneumatic muscle cylinder. In particular, pneumatic muscle cylinders can be controlled very precisely and by virtue of a force output, so that with a pneumatic muscle cylinder the embossing punch of the present embossing device moves extremely precisely into a desired embossing position can be. Such pneumatic muscle cylinders are well known from the prior art, so that their function and structure will not be discussed here.

In particular, with a pneumatic muscle cylinder can be realized structurally simple and low volume of the imprinting very high embossing forces. The embossing device is further characterized in particular by embossing forces greater than 3000 N, preferably greater than 4000 N, from. Such high embossing forces can not be achieved with conventional embossing devices for embossing films on documents, if they include a conventional path-controlled pneumatic drive.

Hydraulically operating Aufprägevorrichtungen, in which a fluid is used as a pressure medium, also have the disadvantage that they are very expensive. Moreover, there is almost always the danger that the fluid can lead to contamination of a structure to be embossed.

It is particularly advantageous if the embossing forces of the embossing device are adjustable in proportion to the air pressure of the pressure-controlled drive device, in particular of a pneumatic muscle cylinder. As a result, a very accurate adjustment of an embossing pressure on an embossing stamp can be achieved by means of which embossing of a structure is to be undertaken.

In this respect, the embossing device is characterized by a pressure-controlled embossing punch. By means of the pressure-controlled embossing die, the embossing forces of the embossing die to be applied can be very precisely and particularly well dosed.

The embossing head additionally comprises, for example, the pressure regulating valve, which enables efficient activation of the pressure-controlled drive device.

Furthermore, it is also advantageous, independently of the other features of the invention, for the embossing device to have the means for setting an embossing time. Advantageously, in this case also the embossing time can be set independently of any thickness variations such as a support plate or a structure to be embossed.

The imprinting device has the means for detecting embossing forces. Such detection means can be implemented in many ways, for example by means of suitable strain gauges. Preferably, at least one pressure sensor is used in the present case as the detection means, wherein a pressure sensor can be arranged structurally simply on the embossing device.

Such a pressure sensor may be mounted beneath a punching boss and measure and detect the displacement and / or deformation of the punching boss when the punch presses against the punching boss during embossing.

Counting an embossing time can be advantageously started when a critical embossing pressure is reached or exceeded.

In this context, the object of the invention is also achieved by a method for impressing structures on security documents, in which an embossing punch is pressed against an embossing boss and the structures are impressed on the security documents, the embossing die being driven by embossing forces set by a pressure regulating valve and a Embossing time is started by a pressure monitor.
The embossing time can either be chosen here, for example, based on a preset signal of the control device or else freely selected.

If the embossing device additionally has a linear guide for guiding the stamping die linearly, the embossing device can in particular be operated exceptionally wear-resistant.

In addition, the linear guide comprises guide columns, on which the embossing die is mounted translationally displaceable, in addition a very high repeatability can be achieved in terms of identical imprints to be carried out, which also a high embossing quality can be ensured.

An advantageous variant of the method provides in this case that the embossing forces are introduced symmetrically into a linear guide of the embossing punch. If the embossing forces are introduced symmetrically, in particular in the linear guide, act on the entire Aufprägevorrichtung no or only negligibly small lateral forces, whereby a particularly high stamping accuracy can be achieved.

In order to be able to quickly move the embossing stamp back after being impressed from an embossing position, it is advantageous if the embossing device has a return stroke device by means of which the embossing stamp can be displaced out of an embossing position into a start or rest position.

The return stroke can hereby only supportive or perform the full work, by means of which the die can be moved to its start or rest position.

A particularly simple and robust construction can be achieved with regard to the return stroke device if the return stroke device comprises at least one spring by means of which the embossing punch can be displaced into its start or rest position.

Advantageously, all the process parameters are easily reproducible by means of the embossing device explained above, so that a multiplicity of identical embossing processes can be carried out.

Further advantages, objects and features of the present invention will be explained with reference to the following description of the appended drawing, in which an embossing device for impressing structures on security documents is shown by way of example.

Figur 1

schematisch eine perspektivische Ansicht einer Aufprägevorrichtung mit einem pneumatischen Muskelzylinder als druckgesteuerte Antriebseinrichtung;

Figur 2

schematisch eine erste seitliche perspektivische Ansicht der Aufprägevorrichtung aus der Figur 1; und

Figur 3

schematisch eine weitere seitliche perspektivische Ansicht der Aufprägevorrichtung aus den Figuren 1 und 2.

It shows

FIG. 1

schematically a perspective view of an imprinting device with a pneumatic muscle cylinder as a pressure-controlled drive device;

FIG. 2

schematically a first lateral perspective view of the imprinting of the FIG. 1 ; and

FIG. 3

schematically another lateral perspective view of the imprinting of the FIGS. 1 and 2 ,

The in the FIGS. 1 to 3 shown embossing device 1 for embossing structures, such as holograms, which are previously on slides (not shown here), consists essentially of a symmetrical frame 2, which in this embodiment mainly a stamping head 3, an embossing boss 4 and a linear guide 5 with comprises two parallel guide columns 6 and 7. Other components and / or component groups of the embossing device 1 are not shown here.

By means of the symmetrical frame 2, embossing forces 8 can be absorbed exceptionally homogeneously by the frame 2, in particular by the guide columns 6 and 7 of the linear guide 5, whereby an extremely high embossing quality of the structures to be applied to the security documents can be achieved. This is due in particular to the fact that the symmetrical frame 2 barely twists during an embossing process, ie when high embossing forces 8 act on the embossing device 1.

Such embossing forces 8 always occur when a guided with the linear guide 5 dies 9 is pressed to impress a foil against the embossing boss 4. For this purpose, the embossing die 9 is displaced out of a start or rest position 10 into an embossing position (not shown here), wherein the embossing die 9 reaches its actual embossing point in this embossing position, in which embossing can take place.

In order to be able to displace the embossing stamp 9 in the required manner on the linear guide 5, the embossing device 1 has a pressure-controlled drive device 12, in particular a pneumatic muscle cylinder. The pneumatic muscle cylinder is mainly integrated or arranged centrally between the two guide columns 6, 7 in the frame 2 of the embossing device 1.

By means of the pneumatic muscle cylinder, the embossing die 9 can be directly controlled and directly displaced, so that the embossing position of the embossing die 9 and thus also the embossing forces 8 can be set particularly precisely. In particular, with respect to different thicknesses of films and substrates to which is impressed, even very high stamping forces 8 up to 4000 N and more can be set and held very precisely by this direct control.

Advantageously, by means of the pneumatic muscle cylinder, a path-controlled drive device, in particular with a toggle mechanism, can be dispensed with, so that the present die 9 is a pressure-controlled die 9.

Advantageously, the embossing forces 8 in this case behave proportionally to a set in the pressure-controlled drive means 12 and vorigenenden air pressure, whereby the embossing forces 8 can also be easily adjusted very precisely. The air pressure at or in the pressure-controlled drive device 12 can be structurally particularly easily regulated by means of a suitable pressure control valve, which is not shown in the drawings. Preferably, the pressure regulating valve is provided close to the embossing head 3, so that it is arranged in the immediate vicinity of the pressure-controlled drive device 12 and thereby directly and as delay as possible can be controlled by a control device, also not shown. For this purpose, the control device receives detection signals of a pressure sensor 16, or actual pressure values, which it evaluates for controlling the pressure control valve and compares them with a setpoint pressure value. The control device controls the pressure regulating valve in such a way that the target pressure value is reached, whereby the desired embossing forces 8 can be ensured.

The pressure-controlled drive device 12 also allows an almost arbitrarily long embossing time, since it is independent of a kinematic sequence of a path-controlled embossing process. In order to set an embossing variable, the embossing device 1 additionally in the drawing, not shown means for adjusting the embossing time, such as a timer, with which the embossing time can be ideally set arbitrarily. The means for adjusting the embossing time can also be realized by the control device.

The means for setting an embossing time are combined in this embodiment with means for detecting embossing forces 8, which are placed in the shape of the pressure sensor 16 below the embossing boss 4, that is, on a side 17 of the embossing boss 4 facing away from the embossing die 9.

Advantageously, the means for setting an embossing time can also be activated or started by means of a pressure monitor 14 as soon as the pressure sensor 16 is preset Embossing forces 8 registered. The pressure monitor 14 is connected upstream of the pressure-controlled drive device 12 or the pneumatic muscle cylinder and is controlled by the control device.

Such embossing forces 8 can be measured by the pressure sensor 16 due to a slight displacement and / or deformation of the embossing boss 4. For example, the means for setting the embossing time by means of a board (not shown here) are designed as hardware. But they can also be run as software, which has the advantage that they can be easily updated for new imprinting operations.

In order to be able to relocate the embossing die 9 out of its embossing position after a successful embossing in the embossing direction 18 and back into its start and stop position 10 with a return stroke 19, the embossing device 1 additionally has a return device 20, which essentially uses a first spring 21 and a second spring 22 is realized. In this respect, the return device 20 has a very robust and reliable construction.

The two springs 21 and 22 are respectively arranged around the guide columns 6 and 7 and the guide columns 6, 7 are located within the spirally formed springs 21 and 22, so that the return device 20 is particularly space-saving provided on the embossing device 1.

It is understood that between the embossing top side 23 of the embossing boss 4 and the embossing underside 24 of the embossing die 9 still support plates (not shown here) can be provided, by means of which further embossing parameters are individually adjustable on the embossing device 1.

LIST OF REFERENCE NUMBERS

1:

Aufprägevorrichtung

2

Symmetrical frame

3

embossing head

4

coining anvil

5

linear guide

6

First guide pillar

7

Second guide post

8th

stamping forces

9

dies

10

Start and rest position

12

Pressure-controlled drive device

13

switching valve

14

pressure switch

16

pressure sensor

17

Opposite side

18

Aufprägerichtung

19

return stroke

20

Rear lifting device

21

First spring

22

Second spring

23

Emboss top

24

Embossing bottom

Claims (12)

1. An embossing apparatus (1) for embossing structures onto security documents, wherein the embossing apparatus (1) comprises an embossing head (3), an embossing stamp (9) and an embossing anvil (4) and the embossing stamp (9) is movable between the embossing head (3) and the embossing anvil (4),
   characterized by
   a pressure-controlled drive means (12) for driving the embossing head (9) by means of embossing forces (8) regulated by a pressure control valve, and a pressure switch (14) for starting the embossing time.
2. The embossing apparatus (1) according to claim 1,
   characterized in that
   the structures are applied to a sheet that can be thermally activated and that can be removed after embossing the structures onto the security document.
3. The embossing apparatus (1) according to claim 1 or claim 2,
   characterized by
   embossing forces (8) larger than 3000 N, preferably larger than 4000 N.
4. The embossing apparatus (1) according to any one of claims 1 to 3,
   characterized in that
   embossing forces (8) of the embossing apparatus (1) can be adjusted proportionally to the air pressure of the pressure-controlled drive means (12), particularly of a pneumatic muscle cylinder.
5. The embossing apparatus (1) according to any one of claims 1 to 4,
   characterized by
   a linear guide (5) for linearly guiding the embossing stamp (9).
6. The embossing apparatus (1) according to claim 5,
   characterized in that
   the linear guide (5) includes guide columns (6, 7) on which the embossing stamp (9) is arranged so as to be displaceable in a translational motion.
7. The embossing apparatus (1) according to any one of claims 1 to 6,
   characterized by
   a return stroke device (18), by means of which the embossing stamp (9) can be displaced from an embossing position into a start and rest position (10).
8. The embossing apparatus (1) according to claim 7
   characterized in that
   the return stroke device (18) comprises at least one spring (21, 22).
9. The embossing apparatus (1) according to any one of claims 1 to 8
   characterized in that
   the embossing head (3) comprises a pressure-control valve, which enables efficient control of the pressure-controlled drive means (12).
10. An embossing method for embossing structures onto security documents, wherein an embossing stamp (9) is pressed against an embossing anvil (4) and the structures are embossed onto the security documents,
    characterized in that
    the embossing stamp (9) is driven by means of embossing forces (8) adjusted by a pressure-control valve, and
    an embossing time is started by a switching valve (14).
11. The embossing method according to claim 10,
    characterized in that
    embossing forces (8) are adjusted by means of a pressure-control valve and are detected by means of a pressure sensor (16).
12. The embossing method according to claim 10 or 11,
    characterized in that
    embossing forces (8) are symmetrically transmitted onto a linear guide (5) of the embossing stamp (9).

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