EP3398781B1 - Wetting method and wetting apparatus for rewetting after application element application and value document substrate - Google Patents

Description

The invention relates to a method for rewetting a web of a printing material after application of application elements.

The invention further relates to a device for moistening a web of a printing material after an application of application elements, wherein the device has a moisture supply device and one of which is supplied with moisture transfer roller which transmits moisture to the web.

The invention also relates to a value document substrate, in particular for producing a value document, a banknote or the like, from a printing substrate, wherein at least one application element is applied to a surface of the substrate and the substrate by a moistening of the printing material after the application of at least one element Has source area in which the substrate is swollen and so a thickness of the substrate is increased.

From the DE 102011119213 A1 It is known to apply to a web of a substrate film elements, so as to produce a value document substrate for later production of documents of value, in particular banknotes. The device described there has at the end of the processing line on a rewet. Such a rewet is also in the DE 102008021944 A1 proposed. The moistening carried out with it is intended to counteract dehydration that occurs during application of the film elements. By the way, a supply of moisture is known in the offset printing for the printing process; As an example, let us look at the WO 2012/146263 A1 directed. Such preparatory However, partial steps of the printing process are not rewetting in the present sense.

In US 5,850,589 Copy paper is more strongly rewetted in areas of higher toner density. DE 4227136 A1 describes a device for rewetting a printed paper web.

The invention is based on the object of improving the quality of a value document substrate to which application elements are applied.

The invention is defined in the independent claims.

According to the invention, a structured rewetting of the web is carried out. The structuring is adapted to the position of the application elements on the web. Areas in which the application elements are applied to the web are left out during moistening. Depending on the configuration of the application elements, however, it may also be expedient to reduce the moistening in these areas. The application element is impermeable to water and preferably a film element.

The invention provides a structured moistening of the web after the application of the water-impermeable application elements, the structuring being adapted to the position of the application elements. This prevents that the usually impermeable application elements are exposed to too much moisture, especially water. This water can thus no longer occur laterally next to the application element in the substrate. As a result, a local non-uniform swelling of the printing material as a result of moistening is avoided, and the flatness of the printing material for the subsequent processing steps, for example Sheeter or pressure, especially screen printing or stitch print, is improved. Here, the moisture absorption during winding of the moistened web is taken into account. By eliminating the areas which carry application elements, it is additionally prevented that remains on the application elements moisture, which would occur at the back of the winding in the overlying web in the substrate and this locally uneven sources with the resulting flatness problem would bring.

After applying water-impermeable application elements to the web, the printing substrate is rewetted to counteract drying out of the printing material, in particular caused by the application. The humidification is carried out structured, z. B. by areas in which the application elements are applied to the web, are left out during moistening. A device for wetting the web after application of application elements has a moisture supply device and a moisture-supplied transfer roller which has a roll mantle in contact with the web, which is structured with respect to the transfer of moisture. By means of the moistening of the web after application of the at least one application element, a substrate thus produced, in particular for producing a value document, a banknote or the like, has a swelling area in which the printing material swells and thus a thickness of the printing substrate is increased. Due to the structured moistening, the source area adjoins the application element without locally stronger swelling and thus caused excessive thickness.

Special benefits are provided by the structured rewetting during the application of application elements, which lie opposite each other on the front and back of the web. This results in a double-sided sealing of the surface of the web. If such application elements have different widths, local swelling along the edges occurs at the edges of the narrower application element within the overlap region, which without structured moistening would lead to buckling in the roll and predilution of the value document substrate, which would sustain the flatness in later processing steps would disturb.

The structuring of the roll mantle with regard to the transfer of moisture to the web can be realized by providing the roll mantle of the moisture transfer roll with recesses at appropriate locations. The recesses are so deep that the roll shell does not contact the web there and does not moisten the web there.

The structuring can also be achieved by structurally applying moisture to the roll shell of the transfer roll. This can be realized in a particularly simple manner by providing a zone diaphragm, which covers the locations of the roll mantle which correspond to the application elements, after spraying a moisture-spraying device. Of course, a zone stop can also be combined with a roller having recesses on its roll shell. Both variants are particularly suitable for cases in which strip-shaped application elements are applied to the printing substrate.

The application element is applied to the web, so it is already present as such before application. Particularly preferably, the application element is a multi-layered application element with at least one full-surface, water-impermeable layer. The water-impermeable layer can be formed, for example, by a film or comprise a hardened lacquer layer.

In the case of application elements which are in the form of patches, it is particularly easy to keep the zone stop free of moistening a strip-shaped area on the path along which the patches are lined up. Likewise, it is possible to moisten the roll in a structured manner in accordance with the patches, for example by means of a moistening device which has a spinning roller rotating synchronously with the roll, which covers the places where patches are to lie. Of course, the recesses on the transfer roller can be structured according to the patches.

Another possibility for structured moistening is a zone-wise heating of the transfer roller, wherein the heated zones correspond to the areas to be spared on the web. Due to the higher temperature, these zones absorb (less or) no moisture and do not transfer it to the web.

In the patches matched designs, care must be taken that the rotational position of the transfer roller or roller is adjusted to convey the web so that the non-wetted areas of the roller shell are exactly where the patches are on the web, while the train goes through.

It has been found that with some substrates, in particular banknotes, which are made on cotton basis, introduced moisture also spreads laterally to some extent in the substrate. It is therefore preferred in a development to make the recessed areas slightly larger than the application elements, so that there is a gap between the moistened areas and the application elements. It should not be larger than 10 mm and preferably between 2 mm and 5 mm wide. With such a gap, the flatness is particularly good, as well as a time-delayed compensation of moisture in the wetted substrate does not lead to distortions.

The moistening of the printing material after the application of the application elements has two effects. On the one hand, the moistened printing material swells. On the other hand, it is clearly roughened on the surface. The swelling effect occurs due to the mentioned spread of moisture in the printing material in an area which is slightly larger than the originally moistened area. For the roughening, this does not apply according to current knowledge. A value document substrate produced with the mentioned gap between the wetting area and the application element therefore has a very characteristic difference between swelling and roughened surface. The area affected by the roughening is smaller than the source area where the thickness change occurred.

Re-wetting generally and in the present case is a moisture loss of the printing material which balances or sets the moisture of the printing material to a predetermined value by adjusting the application of moisture, in particular water. The moisture of the printing material is adjusted by the rewetting in particular to a suitable value for further processing as a web.

It is known to introduce application elements in recesses in order to promote a flat surface. Preferably there is then a gap between the moistened area and the depression provided for the application element, in particular a gap with the dimensions already mentioned.

The present procedure shows a particularly clear effect when applying film-based application elements. In principle, an application of the procedure in the same way is conceivable if other water-impermeable application elements are applied.

Fig. 1

eine Schemadarstellung einer Folienapplikatormaschine ,

Fig. 2

eine Ausführungsform für eine Wiederbefeuchtungseinrichtung, die in der Folienapplikatormaschine vorgesehen ist,

Fig. 3

eine Ausführungsform für eine Übertragungswalze der Wiederbefeuchtungseinrichtung der Fig. 2,

Fig. 4

eine alternative Ausführungsform der Wiederbefeuchtungseinrichtung,

Fig. 5

eine in der Wiederbefeuchtungseinrichtung der Fig. 4 verwendete Zonenblende und deren Zusammenwirkung mit einer Übertragungswalze der Wiederbefeuchtungseinrichtung,

Fig. 6

eine Schnittdarstellung durch Banknotenpapier zur Verdeutlichung der Lage applizierter Applikationselemente,

Fig. 7

eine Schnittdarstellung ähnlich der Fig. 6 mit der Veranschaulichung einer strukturierten Befeuchtung, welche am Banknotenpapier ausgeführt wird,

Fig. 8

eine Darstellung ähnlich der Fig. 7 zur Verdeutlichung eines Nachquellbereichs, der durch eine strukturierte Befeuchtung des Banknotenpapiers erreicht wurde,

Fig. 9

eine Darstellung ähnlich der Fig. 7, wobei ein befeuchteter Bereich einen Abstand zum Applikationselement hält und

Fig. 10

eine Schnittdarstellung ähnlich der Fig. 8 zur Veranschaulichung der Aufrauhwirkung und der Quellwirkung der Befeuchtung.

The invention will be explained in more detail by way of example with reference to the drawings in exemplary embodiments. In the drawings shows:

Fig. 1

a schematic of a film applicator machine,

Fig. 2

an embodiment for a rewet device provided in the film applicator machine,

Fig. 3

an embodiment for a transfer roller of the rewet of the Fig. 2 .

Fig. 4

an alternative embodiment of the rewet device,

Fig. 5

one in the rewet of the Fig. 4 used zone stop and their interaction with a transfer roller of the rewet,

Fig. 6

a sectional representation through banknote paper to illustrate the position of applied application elements,

Fig. 7

a sectional view similar to the Fig. 6 with the illustration of a structured moistening carried out on the banknote paper,

Fig. 8

a representation similar to the Fig. 7 to illustrate a Nachquellbereichs that was achieved by a structured humidification of the banknote paper,

Fig. 9

a representation similar to the Fig. 7 , wherein a moistened area keeps a distance to the application element and

Fig. 10

a sectional view similar to the Fig. 8 to illustrate the roughening effect and the swelling effect of the moistening.

Fig. 1 schematically shows a Folienapplikatormaschine 1, which promotes a provided on a feed roller 2 web 3 along a conveying direction 4 and by sheet application generates a banknote paper 5, which is provided for further processing, in particular for further printing and formed. As an example, an application element with foil, a foil element, is used below. Application machines for strips or patches as application elements with and / or without a separate film are known. On an intermediate carrier or independently existing application elements are applied to a web. The film applicator 1 is designed for roll application and has a film application device 6, as for example from the DE 102011119213 A1 is known. The film application device 6 brings on the web 3 by imprinting or hot applying security elements z. B. in film form. This can be done on one side or two sides on the web 3. In the conveying direction 4 of the film application device 6 is followed by a Wiederbefeuchtungseinrichtung 7, the full surface and usually from both sides Moisture is applied to the web 3. This is usually water, which is usually mixed with a wetting agent. The rewet 7 compensates for dehydration caused by the film applicator 6 in the web 3, and ensures that the banknote paper 5 has a predetermined final moisture content before being rolled onto a reel 8.

The film elements applied by the film application device 6 are impermeable to water. They cover part of the track 3. In order to prevent the moistening, which is carried out by the Wiederbefeuchtungseinrichtung 7, unevenly distributed from the film elements on the web 3 and in particular at the edge of the film elements takes place a greater humidification than at other locations of the web 3, the Wiederbefeuchtungseinrichtung 7 performs a structured moistening, which is adapted to the location and size of the film elements, which were applied by the film application device 6.

In a particularly simple yet highly advantageous embodiment, the structuring is adapted such that the sections of the web 3 on which film elements are located are recessed by the moistening. Sealing portions of the web 3, which were produced by applied film elements are thus not exposed to moisture, so that no increase in moisture takes place at the edge of these sealing elements.

In a first embodiment, the Wiederbefeuchtungseinrichtung 7 is designed as Rollenbefeuchtungsanlage having a sprayed with finely divided drops of water transfer roller 9, which together with a counter-roller 10 which conveyed between these two elements Lane 3 moistened. The transfer roller 6 is acted upon by a spray device with a spray jet 12 with moisture, wherein an adjustable aperture 13 is provided. It shadows the spray jet 12 over the entire length of the transfer roller 9 partially, so that the aperture 13, the amount of moisture which is applied by the spray jet 12 to the transfer roller 9, adjusted.

In the embodiment of the Fig. 2 the foil elements are strip-shaped. In order to adapt the moistening to these strip-shaped film elements which extend along the conveying direction 4 on the web 3, the transfer roller 9 has annular recesses 15 on its roll shell 14. They are so deep that no moisture can be transferred to the web 3 from them. Thus, here along the recess 15 when passing through the web 3, no transmission of moisture is possible. The position of the recesses 15 is adjusted to match the longitudinal extent of the strip-shaped film elements on the web 3.

In a modification of the construction of the Fig. 3 the transfer roller 9 is designed for patch-shaped film elements. The recesses 15 are then not annular, but are the film elements corresponding recesses on the transfer roller 9. During the passage of the web 3 in the Wiederbefeuchtungseinrichtung 7 is then ensured that the recesses on the transfer roller 9 and the patch-shaped film elements on the web third are respectively aligned with each other while the web 3 passes through the rewet device 7 and the transfer roller 9.

It is needless to say that the humidifier 7 in FIG Fig. 2 is shown only schematically. In particular, one moistening is the other Side of the web 3 in the figure not shown for simplicity. This can be easily done by a corresponding doubling of the Fig. 2 reach shown elements, which is designed such that the other side of the web 3 is moistened.

Fig. 4 shows a modified construction in which instead of the recesses 15, a zone aperture 16 is provided, which shadows areas on the transfer roller 9 in front of the spray jet 12, which should not be supplied with moisture for the structured moistening. The zone stop 16 is in Fig. 5 shown schematically in more detail. It comprises visor body 17, which cover said locations on the transfer roller 9. These bodies correspond in their function to the recesses 15 of the construction of Fig. 3 , By means of an adjusting device 18, the position of the visor body 17 can be adapted to a specific embodiment of the film elements on the web 3. Optionally, the diaphragm body in their position and / or extension are adjustable. In their effect, the construction of the Fig. 5 the same as the Fig. 3 with the difference that the areas of the web 3 which are not to be moistened with moisture are now formed not by recesses but by shading of the corresponding sections of the transfer roller 9.

In an embodiment not shown separately, the zone diaphragm 16 or its diaphragm body 17 are bent. The curved zone diaphragm 16 (or the diaphragm body 17) follows the contour of the transfer roller 9 at a predetermined distance. In particular, the radius of the bend can be 1 to 10 mm, preferably 2 to 5 mm, larger than the radius of the transfer roller 9.

The independent of the rotation of the transfer roller 9 diaphragm body 17 naturally allow only the recess strip-shaped areas. If one wishes to avoid patching foil elements from the moistening by means of diaphragms and to moisten the remaining area of the web 3, a modification is possible according to which the zone diaphragm 16 is replaced by a rotating diaphragm roller from the inside of which the spray jet 12 is provided. He then shines through the aperture roller. If the diaphragm roller is rotated to match the rotational speed of the transfer roller 9 and the shutter roller is provided with shading regions which correspond to the foil elements, it is also possible to omit disjointly arranged foil elements in the form of patches from the moistening.

Other ways to achieve the structured moistening, are to provide the transfer roller 9 with heated zones that are tuned in shape and size to the film elements. These heated zones then absorb less or no moisture, so that the film elements are recessed from the moistening. Another possibility is to provide suitable hydrophilic / hydrophobic areas on the transfer roller 9 or electrostatically controlled areas. In both cases, the transfer roller 9 is then designed so that it no moisture or less moisture absorbs at areas which correspond to the film elements on the web 3 and thus the web 3 in a coordinated manner on the location and size of the film elements moistened.

Instead of providing the transfer roller 9 in a structured manner with moisture, it is also possible first to completely moisten the transfer roller 9 and then to dehydrate it in a structured manner, as described in another context in the US Pat WO 2012/146263 A1 is described.

Fig. 6 shows a sectional view through the web 3 after passing through the film application device 6 and before passing through the Wiederbefeuchtungseinrichtung 7. In this state, on the web 3 forming substrate 19 already formed in this embodiment as a longitudinal strip formed film element 20. Fig. 9 shows in a similar sectional view of the structured moistening, which is designed so that a moistened substrate 21 is produced exclusively where no film element 20 is located. This is achieved by the fact that the rewet device 7 applies moisture in moistening regions 22, but not in a recessed region 23, which is matched to the film element 20. In the embodiment of the Fig. 7 corresponds to the recessed area 23 exactly the surface of the web 3, which is covered by the film element 20, so that in the banknote paper 5 of the moistened substrate 21 to the edge of the film elements 20 is not moistened with larger amounts of moisture than in the remaining moistened substrate 21st

Fig. 8 shows the impact of this measure. By moistening with moisture of the printing material swells 21. Since the application in the moistened substrate 21 with moisture is homogeneous and no excess moisture from the moisture-impermeable film element 23 runs to the edge in the substrate 19, there is a swelling 24, over the entire humidification 22nd is homogeneous. This is how Fig. 8 shows, the flatness on the top and bottom of the banknote paper 5 significantly improved. There are no thickness peaks in the banknote paper 5, in particular not at the edge of the film element 20.

Excessive swelling at the edge of the film element 20 would also entail the risk of producing microcracks not recognizable to the naked eye at the boundary between the printing material 19 and the film element 20 or interfere with the connection of the film element to the substrate 19. These problems are equally avoided by the structured humidification.

In the presentation of the Fig. 6 to 8 is located on both sides of the web 3 and thus of the banknote paper 5 each have a film element 20. The moistening is accordingly carried out on both sides. However, this is not mandatory. It is equally possible to provide the film elements 20 only on one side or at least not opposite to the banknote paper 5. In these cases, the structured moistening at the front and back of the web is adjusted accordingly.

Fig. 9 shows by way of example a situation in which a film element 20 is provided only on one side of the banknote paper. Due to the moistening from the other side, moistened printing material 21 thus also sets underneath the film element 20. The schematic representation in Fig. 9 shows a sharp limit for the moistened substrate 21. This is chosen only for the sake of clarity of the drawing so. In fact, the moisture in the printing material 19 will form no sharp boundary and, for example, decrease continuously towards the underside of the film element 20.

Fig. 9 FIG. 12 shows further features that may optionally be used for patterned moistening without being limited to a single-sided film element 20. A first feature is the fact that the recessed area 23 is larger than the film element 20. As a result, a distance range 25 between the wetting area 22 and the film element 20, in which no moisture is applied. By a lateral diffusion, which in certain materials for banknote papers 5 or value document substrates, nevertheless a uniform moistening is achieved, in particular that in Fig. 8 indicated swelling.

Another optional feature that in Fig. 9 is shown, the arrangement of the film element 23 in a recess which is usually production-related slightly larger than the film element 20 itself. Through this depression required for Dickenegalisierung swelling is lower.

Fig. 10 shows a property of the banknote paper 5, when the recessed area 23 is slightly larger than the film element 20. Due to the already mentioned lateral spread of moisture in the substrate 19, then swelling takes place up to the edge of the film element 20. At the same time moistening but also has the effect that the surface of the printing material 19 is roughened. However, such a roughening 26 extends only over the moistening area 22. Unlike the swelling 24, it is not enlarged laterally. A banknote paper 5 which has been produced with structured moistening using a spacing region 25 around the film element 20 thus quite characteristically exhibits a roughening 22 which covers a smaller area than the swelling 24 likewise produced by the moistening.

The structured moistening ensures that the value document substrate does not show an increase in thickness at the edge to the film element. This state is not only given to the roll 8 after being wound up, but also remains in later processing states.

LIST OF REFERENCE NUMBERS

1

press

2

supply roll

3

train

4

conveying direction

5

Banknote paper

6

Foil application device

7

remoistener

8th

role

10

backing roll

9

transfer roller

11

spraying

12

spray

13

cover

14

roll shell

15

recess

16

zone panel

17

visor body

18

setting device

19

substrate

20

application element

21

moistened substrate

22

humidifying

23

recessed area

24

swelling

25

distance range

26

roughening

Claims (12)

1. A method for remoistening a web (3) of a printing stock (19) after an application of water-impermeable application elements (20), wherein
   the moistening is executed in a structured manner, wherein the structuring is adapted to position and size of the application elements (20), and
   regions (23) in which the application elements (20) are applied to the web (3) are left out upon the moistening.
2. The method according to claim 1, characterized in that for moistening a transfer roller subjected to moisture (9) is employed whose roller jacket (14) has recesses (15) at places which correspond to the regions to be left out (23).
3. The method according to claim 1 or 2, characterized in that for moistening a transfer roller (9) is employed and this is supplied with moisture in a structured manner.
4. The method according to any of claims 1 to 3, characterized in that the regions left out (23) are greater than the application elements (20), so that a gap exists between moistened regions (22) and the application elements (20), which is in particular max. 10 mm wide, particularly preferably between 2 mm and 5 mm.
5. A system comprising

   - an apparatus for remoistening a web (3) of a printing stock (19) after an application of water-impermeable application elements (20) as well as

   - the web (3) of the printing stock (19) with the water-impermeable application elements (20),

   wherein the apparatus has a moisture supply device (11) and a transfer roller (9) supplied with moisture therefrom which transfers moisture to the web (3), characterized in that the transfer roller (9) has a roller jacket (14) coming in contact with the web (3) which is structured in terms of the loading with moisture, so that the apparatus (7) moistens the web (3) in a structured manner, wherein the structuring is adapted to position and size of the application elements by leaving out regions (23) upon the transfer of the moisture in which the application elements (20) are applied to the web (3).
6. The system according to claim 5, characterized in that the roller jacket (14) has recesses (15) at the places which correspond to the regions to be left out (23) and thus does not come in contact with the web (3) there.
7. The system according to any of claims 5 or 6, characterized in that the moisture supply device (11) subjects the roller jacket (14) of the transfer roller (9) to moisture in a structured manner.
8. A system according to claim 7, characterized in that the moisture supply device (11) has a spraying device (11), spraying moisture onto the transfer roller (9), and a zonal baffle (16) downstream of the spraying device (11), wherein the zonal baffle (16) comprises baffle bodies (17) which shadow the places of the roller jacket (14) which correspond to the regions to be left out (23).
9. The system according to any of claims 5 to 8, characterized in that the regions left out (23) are greater than the application elements (20), so that a gap exists between moistened regions (22) and the application elements (20), which is in particular max. 10 mm wide, particularly preferably between 2 mm and 5 mm.
10. A value-document substrate, in particular for the manufacture of a value document, a bank note or the like, made from a printing stock (19), wherein at a surface of the substrate (5) at least one water-impermeable application element (20) is applied and the substrate (5) by a moistening of the printing stock (19) after the application of the at least one application element (20) has a swell region (22) in which the printing stock (19) is swollen up and thus a thickness of the printing stock (19) is increased,
    characterized in that the value-document substrate is manufactured by a method according to any of claims 1 to 4, and
    the swell region (22) borders the application element (20) without a locally stronger swelling up and excessive increase in thickness caused thereby.
11. The value-document substrate according to claim 10, characterized in that it has at the surface a roughening region (26) which is likewise generated by the moistening of the printing stock (19) after the application of the at least one application element (20), wherein the roughening region (26) is smaller than the swell region (22), so that a gap exists between application element (20) and roughening region (26) which is in particular max. 10 mm wide, particularly preferably between 2 mm and 5 mm.
12. A value document, manufactured from a value-document substrate according to any of claims 10 to 11.

Images