Method for hydrophilizing surfaces of a print head assembly

1. A method for hydrophilizing surfaces of a printhead assembly, the method comprising steps of:

plasma activating the surfaces of the printhead assembly at atmospheric pressure;

treating the surfaces of the printhead assembly with a treatment solution;

drying the printhead assembly; and

baking the printhead assembly,

wherein the step of plasma activating includes a first propagation of plasma through ink pathways of the printhead assembly, from a nozzle-side of the printhead assembly through to an ink-supply-side of the printhead assembly and a second propagation of plasma through the ink pathways of the printhead assembly, from the ink-supply-side of the printhead assembly through to the nozzle-side of the printhead assembly.

2. A method according to claim 1 , wherein the step of plasma activating the surfaces of the printhead assembly uses an oxygen plasma.

3. A method according to claim 1 , further comprising a step of performing a print quality and electrical test on the printhead assembly.

4. A method according to claim 3 , further comprising a step of assembling the printhead assembly into a printhead cartridge before performing the print quality and electrical test.

5. A method according to claim 4 , further comprising a step of disassembling the printhead cartridge into the printhead assembly after the print quality and electrical test and before the step of treating the surfaces of the printhead assembly with the treatment solution.

6. A method according to claim 3 , wherein the step of performing the print quality and electrical test comprises a step of purging unused ink from the printhead assembly.

7. A method according to claim 3 , wherein the step of performing the print quality and electrical test comprises a step of rinsing the printhead assembly.

8. A method according to claim 3 , wherein the step of performing the print quality and electrical test is performed before the steps of treating the surfaces of the printhead assembly and drying the printhead assembly.

9. A method according to claim 1 , wherein the first propagation is performed before the second propagation.

10. A method according to claim 1 , wherein the step of treating the surfaces of the printhead assembly injects an ethoxylated polyethyleneimine (EPI) solution through the ink pathways of the printhead assembly.

11. A method according to claim 1 , wherein the step of treating the surfaces of the printhead assembly includes blocking the ink-supply-side of the printhead assembly and pressure pulsing the treatment solution through the printhead assembly from the nozzle-side of the printhead assembly.

12. A method according to claim 1 , further comprising a step of diluting the treatment solution with propylene glycol.

13. A method according to claim 1 , wherein the step of drying the printhead assembly supplies purified compressed air through the ink pathways of the printhead assembly.

14. A method according to claim 13 , wherein the purified compressed air is supplied at a pressure of 600 kPa.

15. A method according to claim 13 , wherein the purified compressed air is pulsed through the ink pathways of the printhead assembly.

16. A method according to claim 1 , wherein the step of baking the printhead assembly includes assembling the printhead assembly into a printhead cartridge, and baking the printhead cartridge in an oven.