Printhead assembly having improved adhesive bond strength
View Patent ↗A printhead assembly is provided. The printhead assembly comprises (a) a plurality of printhead integrated circuits comprising; and (b) an ink manifold having a mounting surface, the backside of each printhead integrated circuit being bonded to the mounting surface with an adhesive. Each printhead integrated circuit comprises a plurality of nozzles formed on a front side of the printhead integrated circuit; a plurality of ink supply channels for supplying ink from a backside of the printhead integrated circuit to the nozzles; and a plurality of etched trenches defined in the backside. The adhesive is received, at least partially, in the plurality of etched trenches, thereby increasing the adhesive bond strength whilst avoiding surface roughening of the printhead integrated circuits.
1. A printhead assembly comprising:
(a) a plurality of printhead integrated circuits, each printhead integrated circuit comprising:
a plurality of nozzles formed on a front side of the printhead integrated circuit;
a plurality of ink supply channels for supplying ink from a backside of the printhead integrated circuit to the nozzles, each ink supply channel extending longitudinally along said printhead integrated circuit and each channel being divided into sections by silicon walls; and
a plurality of etched trenches defined in the backside; and
(b) an ink manifold having a mounting surface, the backside of each printhead integrated circuit being bonded to the mounting surface with an adhesive tape comprising a liquid-based adhesive,
wherein:
the adhesive tape has a plurality of laser-drilled holes defined-, said holes being positioned to coincide with ink said silicon walls such that each hole supplies ink to two of said sections, and
said adhesive is received, at least partially, in the plurality of etched trenches.
2. The printhead assembly of claim 1 , wherein each printhead integrated circuit has a thickness of less than 250 microns.
3. The printhead assembly of claim 1 , wherein the ink manifold is a molded ink manifold formed from a polymer.
4. The printhead assembly of claim 1 , wherein the etched trenches have a diameter or a width sufficient to draw in a liquid adhesive by capillary action.
5. The printhead assembly of claim 1 , wherein the etched trenches have a diameter or a width of less than about 10 microns.
6. The printhead assembly of claim 1 , wherein the etched trenches have a depth of at least 20 microns.
7. The printhead assembly of claim 1 , wherein the etched trenches have an aspect ratio of at least 3:1.
8. The printhead assembly of claim 1 , wherein the etched trenches increase the effective surface area of each backside surface by at least 20%.
9. The printhead assembly of claim 1 , wherein each backside surface has a maximum surface roughness R max of less than about 20 nm.
10. The printhead assembly of claim 1 , wherein each backside surface has a maximum surface roughness R max of less than about 5 nm.
11. The printhead assembly of claim 1 , wherein each backside surface has an average surface roughness R a of less than about 20 nm.
12. The printhead assembly of claim 1 , wherein each backside surface has an average surface roughness R a of less than about 5 nm.
13. The printhead assembly of claim 1 , wherein each printhead integrated circuit has a Total Thickness Variation (TTV) of less than about 5 microns.
14. A printer comprising the printhead assembly of claim 1 .
15. The printer of claim 14 , which is a pagewidth inkjet printer.