Method of hydrophobically coating a printhead
View Patent ↗A method of hydrophobizing an ink ejection face of a printhead, whilst avoiding hydrophobizing nozzle chambers and/or ink supply channels is provided. The method comprises the steps of: (a) filling nozzle chambers on the printhead with a liquid; and (b) depositing a hydrophobizing material onto the ink ejection face of the printhead. The method advantageously provides selectivity during deposition of the hydrophobizing material by CVD.
1. A method of hydrophobizing an ink ejection face of a printhead, whilst avoiding hydrophobizing nozzle chambers and/or ink supply channels, the method comprising the steps of:
(a) filling nozzle chambers on the printhead with a liquid; and
(b) depositing a hydrophobizing material onto the ink ejection face of the printhead,
provided that step (a) is performed prior to step (b).
2. The method of claim 1 , wherein the printhead is an inkjet et printhead.
3. The method of claim 1 , wherein the liquid is an inkjet ink.
4. The method of claim 1 , wherein the step of filling the nozzle chambers is priming the printhead with ink.
5. The method of claim 1 , wherein the deposition of the hydrophobizing material is chemical vapour deposition.
6. The method of claim 1 , wherein the ink ejection face comprises atoms available for covalent bonding with the hydrophobizing material.
7. The method of claim 6 , wherein the atoms are oxygen or nitrogen atoms.
8. The method of claim 6 , wherein the hydrophobizing material forms covalent bonds with the ink ejection face.
9. The method of claim 8 , wherein the hydrophobizing material is a silyl chloride.
10. The method of claim 9 , wherein the hydrophobizing material is a silyl monochloride.
11. The method of claim 1 , wherein the hydrophobizing material is a silyl compound comprising a hydrophobic group.
12. The method of claim 11 , wherein the hydrophobizing material is non-polymerizable in the liquid.
13. A printhead obtained by the method according to claim 1 .
14. The printhead of claim 13 comprising a plurality of nozzles formed on a substrate, each nozzle comprising a nozzle chamber, a nozzle opening defined in a roof of the nozzle chamber and an actuator for ejecting ink through the nozzle opening,
wherein at least part of an ink ejection face of the printhead is hydrophobic relative to the inside surfaces of each nozzle chamber.
15. The printhead of claim 14 , wherein each roof forms at least part of the ink ejection face of the printhead, each roof having a hydrophobic outside surface relative to the inside surfaces of each nozzle chamber.
16. The printhead of claim 14 , wherein the ink ejection face is hydrophobic relative to ink supply channels in the printhead, the ink supply channels being configured to supply ink to each nozzle.
17. The printhead of claim 14 , wherein the ink ejection face comprises a layer of hydrophobic material, and the inside surfaces of each nozzle chamber lacks a layer of hydrophobic material.
18. The method of claim 1 , wherein said ink ejection face is comprised of a material selected from silicon nitride, silicon oxide or silicon oxynitride.