The patent's assignee is
News editors obtained the following quote from the background information supplied by the inventors: "The present invention relates to a nozzle plate having a nozzle opening to discharge liquid drops, and a liquid ejecting head and a liquid ejecting apparatus including the nozzle plate.
"In general, an ink jet type recording head known as a representative example of a liquid ejecting head includes a nozzle plate where a plurality of nozzle openings to discharge liquid drops are formed, and a passage forming substrate where a pressure generating chamber communicating with the nozzle opening is formed. In such liquid ejecting head, a silicon substrate is used in the passage forming substrate and the nozzle plate for an increase in nozzle density, and both thereof are bonded with each other by an adhesive agent.
"JP-A-2009-184176 discloses a method for suppressing residue of the ink, in which a surface of a silicon nozzle plate bonded with the passage forming substrate and an inner surface of the nozzle opening are provided with a first ink-resistant protective film formed from an oxide silicon film by thermal oxidation, and a second ink-resistant protective film formed from metal oxide such as a tantalum pentoxide film formed by thermal CVD and plasma CVD and, further, a third ink-resistant protective film (base film) formed from metal oxide such as a tantalum pentoxide film formed by thermal CVD and plasma CVD and a liquid-repellent film (ink-repellent film) are formed on an ink discharge surface.
"Also, JP-A-2004-351923 discloses a structure in which a base film such as a plasma-polymerized film of a silicone material and a liquid-repellent film disposed on the base film such as a metal alkoxide-polymerized molecular film are disposed as the liquid-repellent film of a nozzle discharge surface.
"However, particularly in a case where the nozzle has high density, there is a case where a uniform film is unlikely to be formed on the inner surface of the nozzle opening, particularly around the vicinity of the discharge surface, such that an ink resistance problem is likely to occur when the ink-resistant protective film formed of the metal oxide is disposed by CVD, and where film thickness is likely to be large and not uniform and a problem of non-uniformity of discharged ink drops arises when a sufficient film is to be formed over the entire surfaces. In a case where the above-described nozzle plate is a silicon nozzle plate in which a nozzle hole is formed on the silicon substrate by using anisotropic etching, there is a case where an adhesive property of the ink protective film causes a problem.
"In addition, the base film such as the plasma-polymerized film of the silicone material of JP-A-2004-351923 has a possibility of generating microdefects, and there is a case where a problem such as peeling of the liquid-repellent film arises due to such microdefects."
As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "An object of the invention is to provide a nozzle plate that has excellent liquid resistance on an inner surface of a nozzle opening and a discharge surface, and a liquid ejecting head and a liquid ejecting apparatus using the nozzle plate.
"An aspect of the invention is directed to a nozzle plate in which a plurality of nozzle openings are disposed in a silicon substrate, in which a tantalum oxide film formed by atomic layer deposition is disposed on both surfaces of the silicon substrate and an inner surface of the nozzle opening.
"According to this aspect, the tantalum oxide film that is film-formed by an atomic layer deposition is uniformly and densely formed even on a narrow area such as an inner circumferential surface of the nozzle opening, and functions effectively as the protective film against a strong alkaline liquid and a strong acid solution.
"It is preferable that a thickness of the tantalum oxide film is within a range of 0.3 .ANG. to 50 nm. In this case, liquid resistance is sufficiently ensured, and an open state in the nozzle opening is not affected.
"It is preferable that a silicon thermal oxide film is formed in a lower layer of the tantalum oxide film. In this manner, liquid resistance can be further improved.
"It is preferable that a liquid-repellent film is stacked on the tantalum oxide film on a discharge surface through annealing of a metal alkoxide film. In this case, liquid repellency of the discharge surface is improved, high liquid resistance is ensured in a part where the liquid-repellent film is not formed in a boundary portion between an inner portion of the nozzle opening and an area in the vicinity of the nozzle opening where the liquid-repellent film is formed, and a problem such as peeling of the liquid-repellent film caused by a problem such as erosion of the silicon substrate by a liquid is addressed.
"Another aspect of the invention is directed to a liquid ejecting head including the nozzle plate of the above aspect, a passage forming substrate where a pressure generating chamber that is bonded with the nozzle plate and communicates with the nozzle opening is disposed, and a pressure generation unit that is disposed on an opposite side to the nozzle plate of the passage forming substrate to generate a pressure change in the pressure generating chamber.
"According to this aspect, the nozzle plate is excellent in liquid resistance and has no problem of peeling of the liquid-repellent film, and opening variation of the nozzle opening is small, and thus a liquid ejecting head with little discharge variation and excellent in durability can be achieved.
"Still another aspect of the invention is directed to a liquid ejecting apparatus including the liquid ejecting head of the above aspect. According to this, a liquid ejecting apparatus with little discharge variation and excellent in durability can be achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
"The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.
"FIGS. 1A and 1B are a perspective view and an enlarged cross-sectional view of a main part of a nozzle plate according to Embodiment 1.
"FIGS. 2A to 2D are views showing processes of manufacturing the nozzle plate according to Embodiment 1.
"FIG. 3 is an exploded perspective view of a recording head according to Embodiment 2.
"FIGS. 4A and 4B are a plan view and a cross-sectional view of the recording head according to Embodiment 2.
"FIG. 5 is a cross-sectional view of the recording head according to Embodiment 2.
"FIG. 6 is a schematic structural view of a recording apparatus according to an embodiment."
For additional information on this patent application, see: TADACHI, Kei; TAKAHASHI, Katsuhiro. Nozzle Plate, Liquid Ejecting Head, and Liquid Ejecting Apparatus. Filed
Keywords for this news article include: Silicon, Tantalum, Heavy Metals, Nanotechnology, Transition Elements, Emerging Technologies, Atomic Layer Deposition,
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