EP3603982A1 - System for printing on a substrate - Google Patents

Abstract

The invention relates to a system for printing a substrate, comprising on the one hand a machine (2) with a rotating body (4) for moving the substrate (5), a conveyor device (6) for moving a transfer film (3a to 3c) in the conveying direction (7 ) and partially wrapping the substrate with the transfer film in a wrapping zone (8), an application device (12) arranged upstream of the rotating body for applying a fluid (10) to the moving transfer film, one - arranged upstream of the rotating body and the Application device downstream - first dryer (14) for at least partially drying and / or hardening the fluid, and a second dryer 16) in the area of the wrapping zone for at least partially drying and / or hardening the fluid, and secondly a transfer film set (3) for changing of transfer films (3a to 3c) comprising at least one first transfer film (3a, 3b) with a smooth surface and d at least one second transfer film (3c) with a matt, rough or structured surface. The invention enables changing print jobs, i.e. Execute orders with changing printing techniques, especially finishing techniques.

Description

The invention relates to a system for printing a substrate with the features of claim 1.

Technical field and state of the art

The invention is in the technical field of the graphics industry and there in particular in the field of printing, in particular finishing, of substrates, e.g. by applying ink, embossing material, holograms and / or cold foil transfer material.

Various finishing techniques are already known from the prior art.

The DE 10 2017 207 309 A1 discloses a method for decorating a portion of an at least partially curved surface. Cold foil transfer material can be transferred, for example, by pressing a transfer belt onto the surface of the object to be treated.

The DE 10 2013 016 117 A1 discloses a method and an apparatus for producing and transferring diffractive microstructures to a printing material. A fluid can be applied to an embossing cylinder and the fluid can be dried on a printing material in an area between the application point and the transfer point, the microstructure being fixed in the fluid and the solidified fluid being transferred to the printing material in the form of a film.

The DE 10 2012 011 783 A1 discloses a method for the indirect application of printing fluid to a printing material. In this case, liquid ink can be applied to an intermediate carrier in the image printing process and transferred from the intermediate carrier to a printing material.

The finishing techniques described in the prior art are carried out on specially developed, equipped and separately provided machines. Therefore, if they want to implement various finishing techniques and want to offer correspondingly refined products in their portfolio, print shops have to purchase a large number of different machines, which increases the investment costs for the printing press machinery.

task

It is therefore an object of the invention to provide a system which is improved and, in particular, cost-effective compared to the prior art and which, in particular, enables changing print jobs, i.e. Execute orders with changing printing techniques, especially finishing techniques.

Solution according to the invention

This object is achieved according to the invention by a system with the feature of claim 1. Advantageous and therefore preferred developments of the invention result from the subclaims and from the description and the drawings. The features of the invention, the developments of the invention and the exemplary embodiments of the invention also represent advantageous developments of the invention in combination with one another.

The invention relates to a system for printing on a substrate, comprising on the one hand a machine with a rotating body for moving the substrate, a conveyor device for moving a transfer film in the conveying direction and for partially wrapping the substrate with the transfer film in a wrapping zone, and - in the conveying direction the rotating body upstream - application device for applying a fluid to the moving transfer film, a first dryer - at least partially drying and / or hardening of the fluid - which is upstream of the rotating body and downstream of the application device, and a second dryer in the area of the wrapping zone for at least partially drying and / or hardening of the fluid, and on the other hand a transfer film set for changing transfer films, comprising at least one first transfer film with a smooth surface and at least one second transfer film with a matt, rough or structured surface.

The invention advantageously enables alternate print jobs to be performed, i.e. Orders with changing printing techniques, especially finishing techniques. The invention is in particular an inexpensive system.

Figures and embodiments of the invention

The invention and its preferred developments are described below with reference to the drawings, ie Figures 1 and 2 , described in more detail using at least one preferred exemplary embodiment.

Figur 1:

eine schematische Darstellung einer bevorzugten Ausführungsform eines erfindungsgemäßen Systems; und

Figur 2:

den Ablauf eines erfindungsgemäß durchgeführten Verfahrens.

The figures show:

Figure 1:

a schematic representation of a preferred embodiment of a system according to the invention; and

Figure 2:

the sequence of a method carried out according to the invention.

Figure 1 shows a schematic representation of a preferred embodiment of a system according to the invention for printing or refining or decorating a substrate.

The system 1 comprises on the one hand a machine 2, in particular a printing press and / or finishing machine, and on the other hand a transfer film set 3, in particular a set comprising at least two or at least three mutually different transfer films, for example a first transfer film 3a, a second transfer film 3b and one third transfer film 3c. The first and the second transfer films are shown by way of example as transfer films that can be unwound and unwound, while the third transfer film is shown by way of example as an endlessly rotating transfer film. You can use any type of transfer film several individual foils can be stored and fed to the machine, for which purpose a storage facility and, if necessary, conveyor logistics can be provided.

The machine 2 comprises a rotating body 4 for moving a substrate 5. The substrate can be a flat, web-shaped printing material 5a, e.g. be made of paper, cardboard or plastic film. In this case, the rotating body is a rotatable (transport) cylinder. The substrate can alternatively be a flat, arch-shaped printing material 5b, also e.g. be made of paper, cardboard or plastic film. In this case, the rotating body is a rotatable (transport) cylinder for the sheets or for a belt that transports the sheets. Finally, the substrate can alternatively be an object 5c of any shape, in particular a rotationally symmetrical object, such as a bottle or a can, or it can be at least partially a cylinder. The object can be an object which has previously been produced by an additive method (“printed”). In this case the rotating body is e.g. a rotatable holder, such as a gripping or suction holder for the object. The system 1 according to the invention thus makes it possible, depending on the configuration, to print, in particular to refine, flat ("2D") or non-flat ("3D") substrates with a suitable rotating body. It can preferably also be provided to operate the system alternately, i.e. to print either flat or non-flat substrates, e.g. by changing the rotating body depending on the print job. Provision can also be made to equip the machine with a plurality of rotating bodies, preferably different from one another, and to select the appropriate rotating body depending on the print job.

The machine 2 comprises a conveying device 6 for moving a transfer film 3a to 3c in a conveying direction 7 and for partially wrapping the substrate 5 with the transfer film in a wrapping zone 8. The wrapping zone can comprise two guide rollers 20 for the transfer film, which guide the transfer foil to the substrate put on or even press. The conveyor device can comprise a plurality of transport rollers 9. At least one of the transport rollers can be driven and at least support the film transport. In the wrapping zone, a transfer film 3a to 3c of the transfer film set 3 wraps around the substrate 5, for example the web, the sheet or the object. The wrapping zone can comprise approximately 180 °. In the Wrapping zone, the wrapping transfer film and the substrate to be printed move together and essentially at the same surface speed, making contact. In the looping zone, at least the transfer of a fluid 10 from the surface of the transfer film 3a to 3c to the surface of the substrate 5 takes place, either completely, that is to say approximately 100%, or incompletely by fluid splitting, for example to approximately 50%. Additional material can be transferred with the fluid, for example cold foil transfer material. If the transfer is incomplete, it may be necessary to clean the transfer film, for example with a cleaning device 11, in particular a washing device. Cleaning is useful if the transfer film is a reusable transfer film or an endlessly rotating transfer film. In the case of disposable films, cleaning can be dispensed with. A further advantage of the invention can be seen in the fact that when using UV light for drying / hardening (see below), there is no need for inerting or inert gas, since drying / hardening in (oxygen-free) in the wrapping zone ) There is a gap between the substrate and the transfer film.

The machine 2 comprises an application device 12 which is arranged upstream of the rotary body 4 in the conveying direction 7. The application device applies the fluid 10 to the moving transfer film 3a to 3c. The application device can comprise an ink print head 13 or more, for example four (CMYK) or seven (CMYK + OGV) ink print heads, for example DOD heads for dropwise and preferably imagewise transfer of the fluid. Instead of individual ink printheads, foil-wide ink printhead bars with several ink printheads arranged side by side can also be provided. The ink print heads can be used to apply ink or other fluid, such as an ink-like adhesive or embossing material. The ink print heads can be used to apply a single or multi-colored, possibly also transparent, image; the image can also be an adhesive image or an embossing material image. Alternatively or additionally, roller or spray application devices are possible with which, for example, printing ink or lacquer can be applied. A spray application device can work together with a mask, so that (mask) can be applied according to the image.

The machine comprises a first dryer 14. This is arranged upstream of the rotating body in the conveying direction 7 and downstream of the application device 12, i.e. arranged between these two, and is used for at least partially drying and / or hardening the fluid 10 applied to the transfer film 3a to 3c.

The partial drying and / or hardening (with the first dryer) is also referred to as "intermediate drying" or "intermediate hardening" or as "pinning". When pinning, the viscosity of the fluid - at least on its surface - can be increased and thus an undesired flow of the applied fluid can be prevented. A liquid fluid can be converted into a pasty fluid, e.g. an initially thin and less sticky (and therefore can be applied with an ink printhead) adhesive can be converted into a thicker and sticky state.

The first dryer 14 is preferably a UV dryer, e.g. a UV light emitting gas discharge dryer or UV light emitting LED dryer, or a hot air dryer or an IR emitting dryer, e.g. an LED dryer or a laser dryer. Alternatively, the first dryer can be a combination dryer, i.e. a dryer which comprises two or more of the aforementioned dryers and emits UV (ultraviolet), IR (infrared) or UV and infrared and, if appropriate, also applies hot air.

When drying, water-based fluids are preferably treated, i.e. water is evaporated (the same applies to solvents other than water or fluids based thereon). In contrast, curing is preferably carried out by polymerizing the fluid.

In Figure 1 A control device 15 is shown. This can control components of the machine 1, for example the ink print heads 13, the first dryer 14, a second dryer 16 and / or the cleaning device 11, but also, for example, various drives of the machine, for example for the conveyor device 6 and / or for the rotary body 4. The control takes place via connections provided for this purpose, for example lines or wirelessly.

The second dryer 16 is used for the (preferably repeated) at least partial drying and / or hardening of the fluid 10 and is arranged in the area of the wrapping zone 8, preferably adjacent to the surface of the rotating body 4. The second dryer is preferably a UV dryer, e.g. a UV discharge gas discharge dryer or LED dryer. The second dryer preferably serves to substantially completely dry and / or harden the fluid 10, i.e. the drying out or hardening of the fluid.

The applied fluid 10 is preferably partially dried and / or hardened by radiation and / or hot air from the first dryer 14 and completely dried and / or hardened by radiation from the second dryer 16.

The transfer film set 3 is preferably used to change transfer films 3a to 3c in the case of changing print jobs, in particular finishing orders. It comprises at least a first transfer film 3a, e.g. B. a film for cold film transfer (preferably disposable film) or a first film 3b, z. B. a film for ink transfer in so-called indirect ink printing / inkjet printing (preferably reusable film). The first transfer film 3a, 3b has an essentially smooth surface, so that an unstructured transfer of fluid takes place. The transfer film set 3 further comprises a second transfer film 3c, e.g. B. a foil for embossing foil transfer, impression foil transfer or hologram transfer (preferably reusable foil). More pressure is usually applied when embossing than when taking an impression; e.g. diffractive structures are generated. The second transfer film 3c has a matt, rough or structured surface, so that a structured transfer takes place. Both the unstructured and the structured transfer can take place over the whole area or according to an image. The structure corresponds to the surface quality of the transfer film provided, while the image is generated by driving the application device 13.

The various transfer foils 3a to 3c can be stored on separate unwinders. Alternatively, an unwinder 17 can be provided, which depending on the print job with the matching transfer film 3a to 3c. The machine 2 can also comprise one (or more) rewinder 18 for used transfer films 3a to 3c.

The various transfer foils 3a to 3c can be transparent or at least translucent; Electromagnetic radiation 14a, 16a, e.g. UV or IR radiation can penetrate such a film. In this way, in particular the second dryer 16 can dry and / or harden the fluid 10 through the film (“from the outside”).

Figure 1 shows several ink supply containers 19 which are connected to the ink print heads 13 via ink lines. Provision can be made for an ink print head to be connected to a plurality of ink supply containers and for an additional change from one ink supply container to another ink supply container when transfer foils 3a to 3c are changed, so that the ink print head prints another ink or a different fluid. Alternatively, it can be provided that when changing transfer foils, there is also a change from one ink print head to another ink print head, so that the latter prints the transfer foil with fluid.

The change of transfer foils 3a to 3c and the appropriate change of fluid 10 (and possibly the appropriate change of the rotating body 4) can be carried out by the control device 15, e.g. be coordinated using print job data. All changes can preferably be made automatically by means of correspondingly provided change devices. Alternatively, the changes can be carried out by an operator.

The fluid 10 can be an adhesive, e.g. B. when using foils for cold foil transfer. The fluid can be white ink ("opaque white") or black ink or colored ink, in particular when transparent objects 5c are printed, in particular refined. Black ink can e.g. B. may be advantageous in the production of holograms on (glass) bottles or similar objects. The fluid can be a transparent clear lacquer or a transparent clear lacquer ink and can be used, for example, for the production of optical structures. The fluid can be a metallic ink, ie contain optically effective metal particles. The fluid can be electrical be conductive ink and such elements can be used to print functional elements, for example electrical circuits such as RFID.

Figure 2 shows the sequence of a preferred embodiment of a method carried out with the system according to the invention with the following steps: When applying 21, fluid 10 is applied to one of the transfer foils 3a to 3c by means of the application device 12. During the first drying or pinning 22, the applied fluid is dried and / or hardened (and in particular pinned) by means of the first dryer 14. When the transfer film is pressed 23, a transfer film 3a to 3c is pressed in the wrapping zone 8 onto the substrate 5 or its surface. In this case, fluid 10 applied to the transfer film is transferred to the substrate, for example a web, an arc or an object. When the transfer film 3a to 3c is pulled off 25, the transfer film is again pulled off the surface of the substrate, with fluid 10 remaining on the surface of the substrate.

1. 1. Metallisierung auf Basis einer Transferfolie:
   • Verwendung einer Transferfolie mit Kaltfolienmaterial.
   • Bevorzugt in Verbindung mit einem Rolle-zu-Rolle-Prozess (Abwicklung und Aufwicklung).
   • Verwendete Tinten: UV- Tinten, klare Tintenlacke oder bevorzugt Deckweiß.
   • Bereitstellen des ersten Trockners zum Konditionieren der Tinte, so dass aus der Tinte ein Klebstoffbild wird.
   • Umschlingen der bedruckten Transferfolie um ein bevorzugt zylindrisches Objekt.
   • Transferprozess beim Transport und Härtung mit dem zweiten Trockner (bevorzugt Hg- basierte UV-Quelle) durch die Transferfolie hindurch auf das Objekt oder auf ein flaches Substrat, z.B. Folien, Papiere etc.
2. 2. Hochglänzender klarer Tintenlack oder Silbermetallictinte:
   • Verwendung einer hochglänzenden glatten Transferfolie.
   • Rolle-zu-Rolle-Prozess oder umlaufendes Band (100% Übertrag) mit Mehrfachnutzung.
   • Verwendete Tinten: UV-Metallictinte oder Inkjet-Klarlack .
   • Bereitstellen des ersten Trockners zum Pinnen der Tinte
   • Transferdruck und Endhärtung unter Verwendung des zweiten Trockners als UV-Trockner.
   • Vorteilhaft: der Glanz des Klarlacks bzw. der Glanz und der Metalliceffekt der Metallictinte wird gegenüber der einer Direktbedruckung mit solchen Tinte verbessert
3. 3. Klarlack, der mattiert oder makroskopisch strukturiert wird:
   • Verwendung einer angerauten Folie bzw. einer Folie mit makroskopischer Struktur (Motiv, Bild).
   • Wie bei Beispiel 2, nur wird die Rauheit bzw. die makroskopische Struktur der Transferfolie auf den Lack übertragen.
4. 4. Diffraktive Strukturen, "hologrammartige" Muster:
   • Verwendung einer transparenten Transferfolie mit offenen, diffraktiven, lichtbeugenden Strukturen an der Oberfläche.
   • Verwendung eines klaren oder schwarzen UV-Inkjetlacks.
   • Gelieren des Lacks (optional) mit dem ersten Trockner.
   • Transferdruck und Endhärtung unter Verwendung des zweiten Trockners.
5. 5. Farbige/schwarze Tinten, die in Ihrer Anmutung verändert werden sollen, zum Beispiel Mattierung:
   • Verfahren wie bei Beispiel 3 mit entsprechend rauer Transferfolie.
6. 6. Aufdrucken auf eine Transferfolie, die eine optische Mottenaugenstruktur hat, die als Lichtsammelfunktion für Solarzellen dient:
   • Verfahren wie bei Beispiel 3.
7. 7. Wie Beispiel 1, aber das übertragene Kaltfolientransfermaterial wird als elektrischer Leiter verwendet.

The following are seven examples for finishing printed products:

1. 1. Metallization based on a transfer film:
   • Use of a transfer film with cold film material.
   • Preferably in connection with a roll-to-roll process (processing and winding up).
   • Inks used: UV inks, clear ink varnishes or preferably opaque white.
   • Providing the first dryer to condition the ink so that the ink becomes an adhesive image.
   • Wrapping the printed transfer film around a preferably cylindrical object.
   • Transfer process during transport and curing with the second dryer (preferably mercury-based UV source) through the transfer film onto the object or onto a flat substrate, eg films, papers etc.
2. 2.High gloss clear ink or metallic silver ink:
   • Use a high-gloss, smooth transfer film.
   • Roll-to-roll process or circulating belt (100% transfer) with multiple uses.
   • Inks used: UV metallic ink or inkjet clearcoat.
   • Providing the first dryer for pinning the ink
   • Transfer printing and final curing using the second dryer as a UV dryer.
   • Advantageous: the gloss of the clear lacquer or the gloss and the metallic effect of the metallic ink is improved compared to direct printing with such an ink
3. 3. Clear varnish that is matted or macroscopically structured:
   • Use of a roughened film or a film with a macroscopic structure (motif, picture).
   • As in Example 2, only the roughness or the macroscopic structure of the transfer film is transferred to the lacquer.
4. 4. Diffractive structures, "hologram-like" patterns:
   • Use of a transparent transfer film with open, diffractive, light diffractive structures on the surface.
   • Use a clear or black UV inkjet varnish.
   • Gelling the paint (optional) with the first dryer.
   • Transfer printing and final curing using the second dryer.
5. 5. Colored / black inks that should be changed in their appearance, for example matting:
   • Procedure as in Example 3 with a correspondingly rough transfer film.
6. 6. Print on a transfer film that has an optical moth eye structure that serves as a light collecting function for solar cells:
   • Procedure as in Example 3.
7. 7. As example 1, but the transferred cold foil transfer material is used as an electrical conductor.

LIST OF REFERENCE NUMBERS

1

system

2

machine

3

Transfer foil set

3a to 3c

transfer films

3a

first transfer film

3b

second transfer film

3c

third transfer film

4

body of revolution

5

substratum

5a

train

5b

arc

5c

object

6

Conveyor

7

conveying direction

8th

winding zone

9

transport rollers

10

fluid

11

cleaning device

12

applicator

13

Ink print head

14

first dryer

14a

Radiation / convection

15

control device

16

second dryer

16a

radiation

17

liquidator

18

rewinder

19

Ink reservoir

20

guide rollers

21

Applying fluid

22

first drying

23

Press on the transfer film

24

second drying

25

Peel off the transfer film

Claims (14)

System for printing a substrate, comprising a machine (2) with a rotating body (4) for moving the substrate (5), a conveyor (6) for moving a transfer film (3a to 3c) in the direction of conveyance (7) and partly Wrapping the substrate with the transfer film in a wrapping zone (8), an application device (12) upstream of the rotating body for applying a fluid (10) to the moving transfer film, a first one - upstream of the rotating body and downstream of the application device Dryer (14) for at least partially drying and / or curing the fluid, and a second dryer (16) in the area of the wrapping zone for at least partially drying and / or curing the fluid, and secondly a transfer film set (3) for changing transfer films ( 3a to 3c), comprising at least one first transfer film (3a, 3b) with a smooth surface and at least one second T transfer film (3c) with a matt, rough or structured surface. System according to claim 1,
characterized,
that the application device (12) comprises at least one ink print head (13). System according to claim 2,
characterized,
that the application device (12) comprises at least two ink supply containers (19) for the ink print head (13) and that when changing transfer foils (3a to 3c) an additional change is made from one ink supply container to the other ink supply container. System according to claim 2,
characterized,
that the application device comprises at least two ink print heads (13) and that when changing transfer foils (3a to 3c) you also switch from one inkjet print head to the other inkjet print head. System according to one of the preceding claims,
characterized,
that the first dryer (14) is a UV dryer, a UV gas discharge dryer or a UV-LED dryer which partially cures or finally cures the fluid or a hot air dryer, IR dryer, an IR LED dryer or an IR laser dryer which partially dries or dries the fluid, or that the first dryer is a UV-IR or IR-IR combination dryer. System according to one of the preceding claims,
characterized,
that the second dryer (16) is a UV dryer, a UV gas discharge dryer or a UV LED dryer. System according to one of the preceding claims,
characterized,
that the first dryer (14) and / or the second dryer (16) increases the viscosity of the fluid (10) or converts a liquid fluid (10) into a pasty fluid (10). System according to one of the preceding claims,
characterized,
that at least one transfer film (3a to 3c) of the transfer film set (3) is a transparent or translucent transfer film for drying or curing radiation. System according to one of the preceding claims,
characterized,
that at least one transfer film (3a) of the transfer film set (3) is a film for cold film transfer. System according to one of the preceding claims,
characterized,
that at least one transfer film (3a) of the transfer film set is a film for ink transfer in indirect ink printing. System according to one of the preceding claims,
characterized,
that at least one transfer film (3a to 3c) of the transfer film set (3) is a film for embossing film transfer or impression film transfer or hologram transfer. System according to one of the preceding claims,
characterized,
that the wrapping zone (8) comprises two guide rollers for the transfer film (3a to 3c). System according to one of the preceding claims,
characterized,
that at least one transfer film (3a to 3c) of the transfer film set (3) is a reusable transfer film and is wound onto the substrate (5) after a transfer of fluid (10). System according to one of the preceding claims,
characterized,
that at least one transfer film (3a to 3c) of the transfer film set (3) is an endlessly rotating transfer film.

Images