METHOD FOR PRINTING A PAPER, AND DIGITAL PRINTING DEVICE

Abstract

The disclosure relates to a method for printing a paper by a digital printing system which has a plurality of ink application units for applying printing ink of different colours to the paper. The paper to be printed is guided past the ink application units in a feed direction. The digital printing system has a device which is designed and suitable for preventing or reducing the formation of condensation on the ink application units, and this device is used to prevent or reduce the formation of condensation on the ink application units. The device has a temperature-control device and an electrical controller, wherein the temperature-control device is designed to influence a temperature of the ink application units, and the electrical controller is designed to control the temperature-control device in such a way that the ink application units have different temperatures. The temperatures of the ink application units increase in the feed direction and temperatures of two adjacent ink application units differ by at least 0.5 C. and by at most 1.5 C. The temperatures of the first ink application unit in the feed direction and of the last ink application unit in the feed direction differ by at most 10 C.

Claims

1. A method for printing on a paper by a digital printing facility which has multiple ink application units for applying printing ink of different colors to the paper, the method comprises guiding the paper to be printed on past the ink application units in a feed direction, the digital printing facility comprising a device that is configured to prevent or reduce a build-up of condensation on the ink application units, and the build-up on condensation on the ink application units is prevented or reduced by the device, the device further comprising a temperature control device and an electrical control unit, the temperature control device being configured to influence a temperature of the ink application units and the electrical control unit being configured to control the temperature control device in such a way that the ink application units are at different temperatures, wherein the temperatures of the ink application units increase in the feed direction (16) and the temperatures of two adjacent ink application units differ by at least 0.5 C. and at most 1.5 C., wherein the temperatures of a first ink application unit in the feed direction and a last ink application unit in the feed direction differ by at most 10 C.

2. The method according to claim 1, wherein the temperatures of two adjacent ink application units differ by at least 0.7 C.

3. The method according to claim 1, wherein the temperatures of the first ink application unit in the feed direction and the last ink application unit in the feed direction differ by at most 7 C.

4. The method according to claim 1, wherein the device has at least one air stream deflector that is arranged between two ink application units and is configured and able to deflect an air flow from one ink application unit to an adjacent ink application unit.

5. The method according to claim 4, wherein the device has at least one air stream deflector between each two adjacent ink application units.

6. The method according to claim 1, wherein the device has at least one air suction device that is arranged between two ink application units and is configured and able to suck away air between the two ink application units.

7. The method according to claim 6, wherein the device has at least one air suction device between each two adjacent ink application units.

8. The method according to claim 1, wherein the device has a housing that encloses the ink application units.

9. The method according to claim 1, wherein the digital printing facility comprises a monitoring unit which is configured to detect a build-up of condensation on at least one ink application unit.

10. A digital printing facility that is able and configured to print on a paper using a method according to claim 1.

11. The method according to claim 1, wherein the temperatures of two adjacent ink application units differ by at least 1.0 C.

12. The method according to claim 1, wherein the temperatures of two adjacent ink application units differ by at most by 1.3 C.

13. The method according to claim 1, wherein the temperatures of two adjacent ink application units differ by at most 1.0 C.

14. The method according to claim 1, wherein the temperatures of the first ink application unit in the feed direction and the last ink application unit in the feed direction differ by at most 5 C.

Description

DETAILED DESCRIPTION OF DRAWINGS

[0022] In the following, an embodiment example of the invention will be explained in more detail with the aid of the accompanying figure. It shows:

[0023] The FIGURE shows the schematic view of a digital printing facility according to an embodiment example of the present invention.

DETAILED DESCRIPTION

[0024] The FIGURE depicts a digital printing facility with a printing unit 2 surrounded by a housing 4. It has four ink application units 6, each of which can apply printing ink in one color. Further ink application units 6 are possible as an option. The ink application units 6 apply the printing ink to a printing cylinder 8. In the embodiment example shown, the paper 10 to be printed on is inserted through an opening, not depicted, into the housing 4 from the right and is guided over a first tension pulley 12, the printing cylinder 8 and a second tension pulley 14. The printing cylinder 8 does not serve to transfer printing ink to the paper 10, but to guide the paper 10 past the ink application units 6. The feed direction is indicated by the arrow 16, which represents the direction of rotation of the printing cylinder 8.

[0025] Within the housing 4 of the printing unit 2, a device 18 is arranged between each two 5 neighboring ink application units, said device being configured to reduce or completely prevent the build-up of condensation on the ink application units 6. In the embodiment example shown, the device 18 is an air suction unit, depicted only schematically, and an air flow deflector. The housing 4 also ensures a smaller build-up of condensation on the ink application units 6 and thus also constitutes part of the 10 device 18.