Print head and associated operating method

Patent metadata

Field	Value
Publication number	US-11338312-B2
Application number	US-201716468695-A
Country	US
Kind code	B2
Filing date	Dec 1, 2017
Priority date	Dec 14, 2016
Publication date	May 24, 2022
Grant date	May 24, 2022

Abstract

The disclosure concerns a printhead for the application of a coating agent to a component, in particular for painting a vehicle body component with a paint. The disclosure provides that the printhead is designed in such a way that it enables a color change during coating operation and can be rinsed with a rinsing agent during a color change in order to rinse out coating agent residues from the printhead.

First claim

The invention claimed is:

1. An apparatus, comprising:
a printhead for applying a coating agent to a component, wherein the printhead enables a colour change during coating operation and can be rinsed with a rinsing agent during a colour change in order to rinse out coating agent residues from the printhead;
a coating agent supply for supplying at least one of the coating agent to be applied and the rinsing agent; and
a separate rinsing agent supply for supplying the rinsing agent;
wherein:
a) the printhead has at least one nozzle for dispensing the coating agent,
b) the printhead has at least one control valve for controlling the release of coating agent through the at least one nozzle,
c) the control valve has an electric coil,
d) the at least one control valve has a coil tube on which the coil is wound externally,
e) the printhead has a rinsing agent supply for supplying the rinsing agent, and
f) the rinsing agent supply opens into the coil tube and directs the rinsing agent into the interior of the coil tube.

2. The apparatus according to claim 1 , characterized by
a) a return system for recirculating at least one of the coating agent and rinsing agent; and
b) a return valve for controlling the return flow into the return system.

3. The apparatus according to claim 2 , wherein the return valve is a self-actuated return valve.

4. The apparatus according to claim 2 , wherein the return valve is a proportional valve.

5. The apparatus according to claim 1 , wherein
a) the printhead comprises a plurality of nozzles for dispensing said coating agent,
b) the printhead has a plurality of control valves associated with the individual nozzles and controlling the release of coating agent through the individual nozzles,
c) the rinsing agent supply has branch lines to the individual control valves so that all the control valves are rinsed with the rinsing agent.

6. The apparatus according to claim 5 , wherein the branch lines of the rinsing agent supply are designed such that the supplied rinsing agent is evenly distributed among the branch lines to the control valves so that the control valves are rinsed with substantially the same amount of rinsing agent.

7. The apparatus according to claim 1 , wherein
a) the coil tube has a circular internal cross-section,
b) the coil tube contains a coil core in its interior.

8. The apparatus according to claim 7 , wherein the coil core has a profile cross-section which does not completely fill the internal cross-section of the coil tube in order to leave space for the rinsing agent between the coil tube and the coil core.

9. The apparatus according to claim 7 , wherein the profile cross-section of the coil core is star-shaped.

10. The apparatus according to claim 7 , wherein the profile cross-section of the coil core has in its circumferential surface at least one rinsing groove.

11. The apparatus according to claim 10 , wherein the rinsing groove runs axially.

12. The apparatus according to claim 10 , wherein the rinsing groove runs in circumferential direction.

13. The apparatus according to claim 10 , wherein the rinsing groove runs spirally.

14. The apparatus according to claim 7 , wherein the profile cross-section of the coil core has an axially extending rinsing channel.

15. The apparatus according to claim 7 , wherein the profile cross-section of the coil core is grid-shaped.

16. The apparatus according to claim 7 , wherein the coil core is sealed with respect to the coil tube by means of a seal.

17. The apparatus according to claim 7 , wherein
a) the printhead comprises a plurality of coil tubes, and
b) branch lines branch off from the rinsing agent supply into the coil tubes.

18. The apparatus according to claim 1 , wherein the at least one control valve has a displaceable armature which is displaced as a function of the current supplied to the coil and closes or releases the nozzle as a function of its position.

19. The apparatus according to claim 18 , wherein
a) the armature extends coaxially in the coil tube over part of its length,
b) the armature has an axially permeable profile cross-section in order to be able to pass rinsing agent through between the armature and the inner wall of the coil tube,
c) the anchor has a non-circular profile cross-section in order to leave space for the coating agent.

20. The apparatus according to claim 18 , wherein the rinsing agent supply opens into the coil tube in an axial direction between the armature and the coil core in order to supply the rinsing agent.

21. The apparatus according to claim 18 , wherein the rinsing agent supply opens into the coil tube in an axial direction in the region of the coil core.

22. The apparatus according to claim 18 , wherein
a) the control valve has a displaceable armature which is displaced as a function of the current applied to the coil and closes or releases the nozzle as a function of its position, and
b) the armature is arranged in a guide cage which is permeable to rinsing agent.

23. The apparatus in accordance with claim 18 , wherein
a) the displaceable armature has a central guide hole, and
b) a stationary guide pin projects into the guide hole of the movable armature, and
c) the guide hole can be rinsed in the displaceable anchor core.

24. The apparatus according to claim 1 , further comprising a flexible diaphragm separating the control valve from the coating agent supply so that the control valve is protected by the membrane from contact with the coating agent.

25. The apparatus according to claim 1 , wherein
a) the printhead allows colour change within a colour change time of less than 30 s,
b) the colour change does not take longer than the infeed or outfeed of the coating object from the painting zone, and
c) the colour change takes place in the time gap given by the distance between two coating objects; and
d) the printhead has small colour change losses during a colour change which are smaller than 51, and
e) the printhead has a low rinsing agent consumption during a colour change which is smaller than 101, and
f) the printhead has a plurality of separate rinsing agent supplies for supplying different rinsing agents.

26. The apparatus according to claim 1 , further comprising a colour changer which is arranged upstream of the printhead and is connected on the output side to the printhead in order to feed the printhead selectively with coating agents of different colours.

Assignees

• Duerr Systems Ag

Inventors

• Fritz Hans-Georg
• Wöhr Benjamin
• Kleiner Marcus
• Bubek Moritz
• Beyl Timo
• Herre Frank
• Sotzny Steffen

Classifications

• B05B15/55

  using cleaning fluids · CPC title

• B05B1/3053

  the actuating means being a solenoid · CPC title

• B41J2/1707

  Conditioning of the inside of ink supply circuits, e.g. flushing during start-up or shut-down · CPC title

• B41J2/165

  Prevention {or detection} of nozzle clogging, e.g. cleaning, capping or moistening for nozzles · CPC title

• B05B12/14 Primary

  for supplying a selected one of a plurality of liquids or other fluent materials {or several in selected proportions} to a {spray apparatus, e.g. to a} single spray outlet · CPC title