DEVICE FOR CURING A UV-CURABLE FLUID ON A PRINTING SUBSTRATE BY AN EMITTER

Abstract

A device cures a UV-curable fluid, such as offset or inkjet printing ink, on a substrate by way of an emitter. The emitter includes at least two flash lamps which are disposed in a row. This provides a cost-efficient way of evenly and homogeneously curing UV-curable printing fluids at low environmental impact. There is also described a printing machine with a device for curing UV-curable printing ink.

Claims

1. A device for curing a UV-curable fluid on a printing substrate, the device comprising: an emitter disposed to irradiate the UV-curable fluid on the printing substrate; said emitter having at least two flash lamps disposed in a row.

2. The device according to claim 1, wherein said emitter further comprises a least two flash lamps disposed in a further row or wherein a further emitter includes at least two flash lamps which are disposed in a further row.

3. The device according to claim 1, wherein said flash lamps are tubes with a respective longitudinal axis in a tube direction.

4. The device according to claim 3, wherein said flash lamps in said row and/or said flash lamps in said further row are disposed adjacent one another without any mutual overlap between neighboring said flash lamps.

5. The device according to claim 3, wherein said flash lamps in said row and/or said flash lamps in said further row are disposed adjacent one another with a mutual overlap between neighboring flash lamps.

6. The device according to claim 5, wherein the longitudinal axes of every other one of said flash lamps are disposed on a first straight line in the direction of the row and the longitudinal axes of every further one of the flash lamps are disposed on a second straight line in the direction of the row, and said first and second straight lines are parallel to and spaced apart from one another.

7. The device according to claim 6, wherein said flash lamps on said first straight line are spaced apart from one another by a given distance and said flash lamps on said second straight line are also spaced apart from one another by the given distance.

8. The device according to claim 7, wherein said flash lamps are offset from one another, with said flash lamps on said second straight line being disposed at the centers of the respective gaps between said flash lamps on said first straight line.

9. The device according to claim 3, wherein said longitudinal axes of said flash lamps are disposed with an inclination relative to the direction of the row.

10. The device according to claim 9, wherein the inclination is adjustable.

11. The device according to claim 3, wherein said longitudinal axes of said flash lamps are perpendicular to, or enclose an angle with, a straight line in a direction of the row.

12. A printing machine for applying a UV-curable fluid to a printing substrate, the printing machine comprising: at least one device according to claim 1 for curing the UV-curable fluid on the printing substrate.

13. The printing machine according to claim 12, configured to print on webs or sheets of a printing material.

14. The printing machine according to claim 13, wherein the sheets or webs are conveyed along a direction of transport in the printing machine and said device is disposed in the printing machine in a transverse direction transverse to the direction of transport.

15. The printing machine according to claim 14, wherein said device is configured to generate a substantially homogeneous distribution of UV light in a transverse direction.

16. The printing machine according to claim 14, wherein said device is configured to generate a substantially homogeneous distribution of UV light in the direction of transport.

17. The printing machine according to claim 13, wherein the sheets or webs are conveyed along the direction of transport in the printing machine and said device is disposed in the direction of transport in the printing machine.

18. The printing machine according to claim 17, wherein said device is configured to generate a substantially homogeneous distribution of UV light in a transverse direction.

19. The printing machine according to claim 17, wherein said device is configured to generate a substantially homogeneous distribution of UV light in the direction of transport.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0048] FIG. 1 is a schematic partial side view of an exemplary embodiment of the invention;

[0049] FIG. 2 is a schematic top view of a preferred exemplary embodiment of the device according to the invention;

[0050] FIGS. 3-7 are schematic top views of several additional exemplary embodiments of a device according to the invention; and

[0051] FIG. 8 is a top view of a further exemplary embodiment of the invention.

[0052] Repetitive reference symbols are left out in some of the drawing views for reasons of clarity.

DETAILED DESCRIPTION OF THE INVENTION

[0053] Referring now to the figures of the drawing in detail and first, in particular, to FIG. 1 thereof, there is shown a schematic side view of a preferred exemplary embodiment of a device of the invention. There is shown a printing machine 1 for printing on a flat printing substrate 2, such as paper, with a UV-curable fluid 3, for instance lithographic offset printing ink.

[0054] The printing machine comprises a device 4 for UV-curing according to the invention. By way of example, the device 4 has multiple emitters, namely an emitter 5 and at least one further emitter 5′. Every emitter comprises at least one flash lamp 6. The flash lamps may be embodied as tubes 6a, for instance as gas discharge tubes such as xenon flash lamps. The flash lamps generate UV radiation 6b to cure the printing fluid 3. As an example, the emitters are disposed along a curved plane 7 of a carrier 7a. The curvature of the plane is preferably adjustable (and thus adaptable to varying printing substrates 2 or transport cylinders). For this purpose, a motor 17 and an associated control device 18 for controlling the curvature of the carrier (potentially in a closed control loop) may be provided.

[0055] FIG. 2 is a schematic top view of a preferred exemplary embodiment of a device according to the invention. There is shown the printing machine 1 and the printing substrate 2 with a printed image 2a of a printing fluid 3, as well as a device 4 of the invention.

[0056] The device 4 comprises at least one emitter 5. As an example, five different emitters 5 are shown. However, the device preferably only has emitters of identical construction. As shown, the flash lamps 6 of the emitters 5 may have different arrangements and/or orientations: For instance, (from top to bottom) coaxial, offset relative to one another, inclined at different angles, or parallel to one another. Details will be shown in the following figures.

[0057] The emitters 5 are preferably oriented in a direction transverse to a direction of transport 8 (of the printing substrate 2), i.e., in a transverse direction 9.

[0058] FIG. 3 is a schematic top view of a further preferred exemplary embodiment of a device of the invention. The top of the figure illustrates an example of a single flash lamp 6 to indicate its longitudinal axis. Below, a number of flash lamps 6 are shown. They are disposed to be coaxial to one another in a row 10. The row has a direction 11 parallel to the transverse direction 9. The longitudinal axes 13 of the flash lamps 6 are on a straight line 12 in the direction of the row 10. By way of an example, a further row 10′ of the emitter 5 is shown.

[0059] FIG. 4 is a schematic top view of a further preferred exemplary embodiment of a device of the invention. A number of flash lamps 6 are shown. They are disposed to be offset relative to one another in a row 10. The row has a direction 11 parallel to the transverse direction 9. The longitudinal axes 13 of the flash lamps 6 are on a second straight line 12 parallel to direction 11 in the direction of row 10. The flash lamps 6 arranged to be offset to one another on the two straight lines 12 are shown to have an overlap 14. The flash lamps 6 of a respective straight line 12 are further shown to be spaced apart from one another by a distance 15, i.e. there is a gap between them. Finally, the flash lamps 6 on one straight line 12 are shown to be disposed at the center of the respective gaps between the flash on the other straight line 12.

[0060] FIG. 5 is a schematic top view of a further preferred exemplary embodiment of a device of the invention. Multiple flash lamps 6 are shown. They are disposed in a row 10 and are inclined, i.e. each flash lamp has an inclination 16 (or an angle different than 0° and 180°) relative to the straight line 12. The row has a direction 11 parallel to the transverse direction 9. The inclination is shown to be adjustable. For this purpose, a motor 17 with a control device for controlling the motor/the inclination, potentially in a closed control loop, is provided.

[0061] FIG. 6 is a further schematic top view of a further preferred exemplary embodiment of a device of the invention. Compared to FIG. 5, the flash lamps 6 are shown to have a different inclination 16.

[0062] FIG. 7 is a further schematic top view of a further preferred exemplary embodiment of the invention. Here, the flash lamps/the longitudinal axes 13 thereof are shown to be oriented in parallel with the direction of transport 8.

[0063] FIG. 8 is a schematic top view of a further preferred exemplary embodiment of a device of the invention. In this exemplary embodiment, the row 10 of emitters 5 (or rather an associated straight line 12) extends in parallel with the direction of transport 8 of the printing substrate 2. The longitudinal axes 13 of the flash lamps 6 extend in a direction perpendicular to the direction of transport, i.e., parallel to the transverse direction 9. In this example, multiple modules 4a of the device 4 with a respective (page-wide) flash lamp 6 are shown to be disposed in printing units and/or varnishing units 1a of the printing machine 1 and one module 4a with a (page-wide) flash lamp 6 is shown to be disposed in a delivery 1b of the printing machine 1.

[0064] The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention:

[0065] printing machine [0066] 1a printing unit(s), varnishing unit(s) [0067] 1b delivery [0068] 2 printing substrate [0069] 2a printed image [0070] 3 fluid [0071] 4 device [0072] 4a module(s) [0073] 5 emitter [0074] 5′ further emitter [0075] 6 flash lamp(s) [0076] 6a tubes [0077] 6b UV radiation [0078] 7 curved plane [0079] 7a carrier [0080] 8 direction of transport [0081] 9 transverse direction [0082] 10 row(s) [0083] 10′ further row(s) [0084] 11 direction [0085] 12 straight line [0086] 13 longitudinal axis/axes [0087] 14 overlap [0088] 15 spacing, gap(s) [0089] 16 inclination [0090] 17 motor [0091] 18 device for controlling (potentially in closed control loop)