PRINTING SYSTEM WITH SELF-PURGE, SEDIMENT PREVENTION AND FUMES REMOVAL ARRANGEMENTS

• US 20140375721A1
• Filed: 06/29/2014
• Published: 12/25/2014
• Est. Priority Date: 05/02/2010
• Status: Active Grant

• Current Assignee: XJet Ltd.
• Original Assignee: XJet Ltd.
• Inventors: GOTHAIT, Hanan, KRITCHMAN, Eli, MIMON, Ronen
• Granted Patent: US 9,481,178 B2
• Time in Patent Office: Days
• US Class Current: 347/28
• CPC Class Codes: B29C 64/112 using individual droplets, e.g. from jetting heads
• CPC Class Codes: B29C 64/209 Heads; Nozzles
• CPC Class Codes: B29C 64/35 Cleaning
• CPC Class Codes: B29C 64/357 Recycling
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 40/00 Auxiliary operations or equipment, e.g. for material handling
• CPC Class Codes: B41J 2/04566 detecting humidity
• CPC Class Codes: B41J 2/165 Prevention or detection of nozzle clogging, e.g. cleaning, capping or moistening for nozzles
• CPC Class Codes: B41J 2/16523 Waste ink transport from caps or spittoons, e.g. by suction Collecting or collectors of waste ink B41J2/1721
• CPC Class Codes: B41J 2/16526 by applying pressure only
• CPC Class Codes: B41J 2/16552 using cleaning fluids
• CPC Class Codes: B41J 2/1714 Conditioning of the outside of ink supply systems, e.g. inkjet collector cleaning, ink mist removal B41J2/08, B41J2/16517, B41J2/18 take precedence
• CPC Class Codes: B41J 2/18 Ink recirculation systems
• CPC Class Codes: B41J 2002/16502 Printhead constructions to prevent nozzle clogging or facilitate nozzle cleaning
• CPC Class Codes: B41J 2002/16558 Using cleaning liquid for wet wiping

Abstract

A printing head assembly with integrated purge mechanism is disclosed. The printing head assembly comprises: (a) a liquid dispensing head comprising one or more dispensing nozzles enclosed in a nozzle plate, driven by at least first and second pressures, and (b) a shielding mask including an opening in front of the one or more nozzles, wherein the opening being configured such that when printing liquid is dispensed from the head driven by the first pressure, the liquid being dispensed in pulses through the opening in the shielding mask, and (ii) when purge printing liquid is dispensed from the head driven by the second pressure, the liquid being drawn to a capillary gap formed between the shielding mask and the nozzle plate thereby removing the purge printing liquid from the nearby nozzles.

Claims

1. A method for printing by an inkjet head, comprising the steps of:

(a) wetting a nozzles plate of the inkjet head, said nozzles plate including jetting nozzles; and

(b) managing liquid vapor in proximity to the wetted nozzles plate to maintain said wetting of said nozzles plate,

thereby preventing accumulation of solid sediment on said nozzles plate.

2. The method of claim 1 wherein said wetting uses liquid droplets condensed from said liquid vapor.

3. The method of claim 1 wherein said step of wetting is at a time selected from the group consisting of:

(a) before printing with the inkjet head;

(b) during printing with the inkjet head; and

(a) between printings of the inkjet head.

4. The method of claim 1 wherein said step of managing is at a time selected from the group consisting of:

(a) before printing with the inkjet head;

(b) during printing with the inkjet head; and

(a) between printings of the inkjet head.

5. The method of claim 1, wherein said liquid vapor is provided by a source selected from the group consisting of:

(a) fumes that emerge from printing liquid ejected from said jetting nozzles accumulated on a heated surface; and

(b) fumes that emerge from a hot pool of volatile liquid underneath the inkjet head while the inkjet head exits a printing area.

6. The method of claim 1 wherein the step of managing includes removing part of said liquid vapor by an auxiliary suction system to maintain said wetting of said nozzles plate at a predefined level of moisture adjacent to said nozzles plate.

7. The method of claim 1 wherein the step of managing includes removing a first portion of said liquid vapor and leaving a second portion of said liquid vapor by an auxiliary suction system, to maintain said wetting of said nozzles plate.

8. The method of claim 1 wherein the step of managing includes removing 80% to 95% of said liquid vapor by an auxiliary suction system to maintain said wetting of said nozzles plate.

9. The method of claim 1, further comprising the step of:

(c) wiping said nozzles plate intermittently to control said wetting of said nozzles plate.

10. The method of claim 1, further comprising the step of:

(c) shielding the inkjet head partially from a printed substrate'"'"'s heat and fumes using a shielding mask, said shielding mask including an opening, to maintain a predefined level of moisture adjacent to said nozzles plate.

11. The method of claim 10, wherein an amount of fumes spread near said jetting nozzles is controlled by aligning said jetting nozzles to an edge of said opening through said shielding mask.

12. The method of claim 1, wherein a purge sequence of the inkjet head removes liquid droplets from said nozzles plate.

13. A system for printing by an inkjet head, the system comprising:

(a) a processing system containing one or more processors, said processing system being configured to;

(i) wet a nozzles plate of the inkjet head, said nozzles plate including jetting nozzles; and

(ii) manage liquid vapor in proximity to the wetted nozzles plate to maintain said wetting of said nozzles plate,

thereby preventing accumulation of solid sediment on said nozzles plate.

14. The system of claim 13 wherein said processing system is further configured to wet said nozzles plate using liquid droplets condensed from said liquid vapor.

15. The system of claim 13 wherein said processing system is further configured to wet said nozzles plate at a time selected from the group consisting of:

(a) before printing with the inkjet head;

(b) during printing with the inkjet head; and

(a) between printings of the inkjet head.

16. The system of claim 13 wherein said processing system is further configured to manage liquid vapor at a time selected from the group consisting of:

(a) before printing with the inkjet head;

(b) during printing with the inkjet head; and

(a) between printings of the inkjet head.

17. The system of claim 13 wherein said liquid vapor is provided by a source selected from the group consisting of:

(a) fumes that emerge from printing liquid ejected from said jetting nozzles accumulated on a heated surface; and

(b) fumes that emerge from a hot pool of volatile liquid underneath the inkjet head, while the inkjet head exits a printing area.

18. The system of claim 13 wherein said processing system is further configured to:

(iii) activate wiping said nozzles plate intermittently to control said wetting of said nozzles plate.

19. The system of claim 13 further comprising:

(b) an auxiliary suction system configured to manage liquid vapor by;

(i) removing a first portion of said liquid vapor; and

(ii) leaving a second portion of said liquid vapor,

thereby maintaining said wetting of said nozzles plate at a predefined level of moisture adjacent to said nozzles plate.

20. The system of claim 13 further comprising:

(b) a shielding mask configured to shield the inkjet head partially from a printed substrate'"'"'s heat and fumes, said shielding mask including an opening, to maintain a predefined level of moisture adjacent to said nozzles plate.

21. The system of claim 20, wherein an amount of fumes spread near said jetting nozzles is controlled by aligning said jetting nozzles to an edge of said opening through said shielding mask.

22. The system of claim 13, wherein said processing system is further configured to:

(iii) activate a purge sequence of the inkjet head to remove liquid droplets from said nozzles plate.