Ink degassing for circulating ink supply systems in ink jet printers
View Patent ↗An ink circulation system includes a supply subtank for supplying ink to an ink jet print head and a return subtank returning the ink not ejected by the ink jet print head. A print circulation path links the supply subtank with the ink jet print head and the return subtank for providing a print flow of ink from the supply subtank to the ink jet print head, the return subtank, and back to the supply subtank. A degas circulation path links the supply subtank with a through-flow degassing unit for providing a degas flow of ink from the supply subtank to the through-flow degassing unit and back to the supply subtank. The ink circulation system improves the degassing quality of the ink supplied to the ink jet print head of a printing apparatus is provided.
1. An ink circulation system for use in a drop on demand ink jet printing apparatus, the ink circulation system comprising:
an ink jet print head;
a supply subtank arranged to contain a supply of ink to be ejected by the ink jet print head;
a return subtank arranged to contain a return of the ink not ejected by the ink jet print head;
a print circulation path arranged to couple the supply subtank with the ink jet print head and the return subtank and arranged to provide a print flow of the ink from the supply subtank to the ink jet print head, then to the return subtank, and then back to the supply subtank;
a through-flow degassing unit arranged to degas the ink; and
a degas circulation path arranged to couple the supply subtank with the through-flow degassing unit and arranged to provide a degassed flow of the ink from the supply subtank to the through-flow degassing unit and then back to the supply subtank.
2. The ink circulation system according to claim 1 , wherein the print circulation path and the degas circulation path have a common path segment located directly upstream of the supply subtank, and the through-flow degassing unit is located in the common path segment.
3. The ink circulation system according to claim 1 , wherein the print circulation path includes a print circulation pump, the degas circulation path includes a degas circulation pump, and the print circulation pump and the degas circulation pump are arranged to operate independently from each other for controlling a print flow rate of the ink independent from a degas flow rate of the ink.
4. The ink circulation system according to claim 2 , wherein the common path segment includes a circulation pump, and a merging point of the print circulation path and the degas circulation path into the common path segment includes a 3-way valve arranged to control a flow ratio between a print flow rate of the ink and a degas flow rate of the ink.
5. The ink circulation system according to claim 3 , wherein the degas flow rate is larger than the print flow rate.
6. The ink circulation system according to claim 4 , wherein the degas flow rate is larger than the print flow rate.
7. The ink circulation system according to claim 3 , wherein the degas flow rate is at least 1000 ml/hr.
8. The ink circulation system according to claim 4 , wherein the degas flow rate is at least 1000 ml/hr.
9. The ink circulation system according to claim 5 , wherein the degas flow rate is at least 1000 ml/hr.
10. The ink circulation system according to claim 6 , wherein the degas flow rate is at least 1000 ml/hr.
11. The ink circulation system according to claim 1 , further comprising a filter arranged between the through-flow degassing unit and the supply subtank to remove clogged or gelled material in the ink.
12. The ink circulation system according to claim 2 , further comprising a filter arranged between the through-flow degassing unit and the supply subtank to remove clogged or gelled material in the ink.
13. The ink circulation system according to claim 3 , further comprising a filter arranged between the through-flow degassing unit and the supply subtank to remove clogged or gelled material in the ink.
14. The ink circulation system according to claim 4 , further comprising a filter arranged between the through-flow degassing unit and the supply subtank to remove clogged or gelled material in the ink.
15. The ink circulation system according to claim 1 , wherein the print circulation path and the degas circulation path are supported on a carriage arranged to reciprocate across a printing medium.
16. The ink circulation system according to claim 2 , wherein the print circulation path and the degas circulation path are supported on a carriage arranged to reciprocate across a printing medium.
17. The ink circulation system according to claim 3 , wherein the print circulation path and the degas circulation path are supported on a carriage arranged to reciprocate across a printing medium.
18. The ink circulation system according to claim 4 , wherein the print circulation path and the degas circulation path are supported on a carriage arranged to reciprocate across a printing medium.
19. A method for providing a flow of a degassed ink to an ink jet print head, the method comprising:
using an ink circulation system as defined in the claim 1 .
20. A method for providing a flow a degassed ink to an ink jet print head, the method comprising:
using an ink circulation system as defined in the claim 2 .
21. A method for providing a flow a degassed ink to an ink jet print head, the method comprising:
using an ink circulation system as defined in the claim 3 .
22. A method for providing a flow a degassed ink to an ink jet print head, the method comprising:
using an ink circulation system as defined in the claim 4 .
23. An ink jet printing apparatus comprising:
an ink circulation system as defined in claim 1 .
24. An ink jet printing apparatus comprising:
an ink circulation system as defined in claim 2 .
25. An ink jet printing apparatus comprising:
an ink circulation system as defined in claim 3 .
26. An ink jet printing apparatus comprising:
an ink circulation system as defined in claim 4 .