Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1998-04-30
2001-05-15
Fuller, Benjamin R. (Department: 2855)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06231169
ABSTRACT:
BACKGROUND OF INVENTION
The present invention relates to an ink jet recording head for expanding or contracting a part of a pressure generating chamber communicating with a nozzle aperture by an actuator for flexural oscillation so as to jet an ink droplet from the nozzle aperture.
An ink jet recording head has two types: a piezoelectric vibration type for mechanically deforming a pressure generating chamber and pressurizing ink; and a bubble jet type provided with a heater element in a pressure generating chamber for pressurizing ink by the pressure of bubbles generated because of the heat of the heater element. The piezoelectric vibration type of recording head is further classified into two types of a first recording head using a piezoelectric vibrator displaced in an axial direction; and a second recording head using a piezoelectric vibrator displaced by flexure. As for the first recording head, although high-speed driving is enabled and recording in high density is enabled, there is a problem that the number of manufacturing processes is many because cutting is required for machining a piezoelectric vibrator and three-dimensional assembly is required when a piezoelectric vibrator is fixed to a pressure generating chamber.
In the meantime, because for the second recording head, as a silicon monocrystalline substrate is used for base material, a passage such as a pressure generating chamber and a reservoir is formed by anisotropic etching, an elastic film can be made extremely thin, the pressure generating chamber and a piezoelectric vibrator can be formed very precisely respectively by a technique for forming the piezoelectric vibrator using film forming technique such as sputtering piezoelectric material, the opening area of the pressure generating chamber can be reduced as much as possible and recording density can be enhanced.
However, to enhance recording density, a wall for partitioning pressure generating chambers is required to be made thin, as a result, the rigidity of the wall for partitioning pressure generating chambers is deteriorated and there occur problems of crosstalk, the failure of jetting an ink droplet and others.
SUMMARY OF INVENTION
The present invention is made to solve such problems and the object is to provide an ink jet recording head in which the rigidity of a partition for partitioning pressure generating chambers of a passage formed substrate can be enhanced without thickening the partition for partitioning pressure generating chambers.
According to the first aspect of the invention, there is provided an ink jet recording head comprising: a nozzle;
a passage formed substrate having partitions forming at least a row of pressure generating chambers, which is communicated with said nozzle;
an elastic film forming a part of the pressure generating chambers;
a piezoelectric vibrator formed on a diaphragm opposite to said pressure generating chamber; and
a backing member joined to the side of the piezoelectric vibrator and having partitioning walls forming a concave portion being spaced to extent that a movement of the piezoelectric vibrator is not prevented, and fixed to the passage formed substrate such that each partitioning wall is opposite to the partition of the passage formed substrate.
In the first aspect, the displacement of the piezoelectric active part is received by the backing member fixed to the passage formed substrate and the partition of the passage formed substrate is prevented from being bent.
According to the second aspect of the invention, there is provided the ink jet recording head according to the first aspect, wherein whole faces of the partitioning walls opposite to the passage formed substrate are joined to the passage formed substrate.
In the second aspect, the backing member is securely fixed to the passage formed substrate and crosstalk is securely prevented.
According to the third aspect of the invention, there is provided the ink jet recording head according to the second aspect, wherein the elastic film and an lower electrode of said piezoelectric vibrator are formed in a part joined to the partitioning walls with the passage formed substrate.
In the third aspect, the backing member and the passage formed substrate are joined via the diaphragm and crosstalk is securely prevented.
According to the fourth aspect of the invention, there is provided the ink jet recording head according to the second aspect, wherein: only the elastic film is formed in a part joined to the partitioning walls with the passage formed substrate.
In the fourth aspect, the backing member and the passage formed substrate are joined via only the elastic film and crosstalk is securely prevented.
According to the fifth aspect of the invention, there is provided the ink jet recording head according to any one of the first to fourth aspects, wherein the partitioning wall has a communicating part which communicates with adjacent the concave portion.
In the fifth aspect, as the concave portions are connected via the communicating part, the variation of pressure in each concave portion is relaxed.
According to the sixth aspect of the invention, there is provided the ink jet recording head according to the fifth aspect, wherein the communicating part is not opposite to the face of the partitioning walls opposite to the passage formed substrate.
In the sixth aspect, the face opposite to the passage formed substrate of the partitioning wall is never reduced by the communicating part and crosstalk is securely prevented.
According to the seventh aspect of the invention, there is provided the ink jet recording head according to any one of the preceding aspects, wherein the width of the concave portion of the backing member is formed such that the width is wider than the width of the pressure generating chamber.
In the seventh aspect, the rigidity of the diaphragm opposite to each pressure generating chamber is not enhanced by the partitioning wall.
According to the eighth aspect of the invention, there is provided the ink jet recording head according to any one of the preceding aspects, wherein dry fluid is sealed in space in the concave portion of the backing member.
In the eighth aspect, the durability of the piezoelectric layer is enhanced.
According to the ninth aspect of the invention, there is provided the ink jet recording head according to any one of preceding aspects, wherein the passage formed substrate and the backing member are made of the same material
In the ninth aspect, deformation due to the junction of the backing member is prevented.
According to the tenth aspect of the invention, there is provided the ink jet recording head according to any one of the preceding aspects, wherein: the pressure generating chambers are formed by anisotropically etching a silicon monocrystalline substrate; and each layer of the piezoelectric vibrator is formed by a film forming method and lithography.
In the tenth aspect, a large number of ink jet recording heads provided with nozzle apertures in high density can be relatively easily manufactured.
According to the eleventh aspect of the invention, there is provided the ink jet recording head according to any one of the preceding aspects, wherein: a reservoir which communicates with the pressure generating chamber is formed in the passage formed substrate; and a nozzle plate having nozzle apertures, each communicating with the respective pressure generating chamber, is attached to the passage formed substrate.
In the eleventh aspect, an ink jet recording head for jetting ink from a nozzle aperture can be readily realized.
According to the twelfth aspect of the invention, there is provided the ink jet recording head according to any one of the first to tenth aspects, further comprising: a passage unit attached to the passage formed substrate, the passage unit having a common ink chamber for supplying ink to the pressure generating chambers and a passage respectively connecting the pressure generating chamber and the nozzle aperture.
In the twelfth aspect, ink is jetted from the above nozzle aperture via the passa
Sakai Shinri
Yazaki Shiro
Dickens C
Fuller Benjamin R.
Seiko Epson Corporation
Sughrue Mion Zinn Macpeak & Seas, PLLC
LandOfFree
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