Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2001-04-04
2003-01-07
Vo, Anh T. N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S072000
Reexamination Certificate
active
06502930
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an ink-jet recording head, in which a piezoelectric element is formed via a vibration plate in a portion of a pressure generating chamber communicating with a nozzle orifice that ejects ink droplets, and ink droplets are ejected by displacement of the piezoelectric element, and to a manufacturing method of the same and an ink-jet recording apparatus.
BACKGROUND ART
With regard to the ink-jet recording head, in which a portion of a pressure generating chamber communicating with a nozzle orifice that ejects ink droplets is constituted of a vibration plate, and the vibration plate is deformed by a piezoelectric element to pressurize ink in the pressure generating chamber, thus ink droplets are ejected from the nozzle orifice, there are two types of recording heads put into practical use: one using a piezoelectric actuator of longitudinal vibration mode with a piezoelectric element expanding and contracting in the axis direction; and the other using a piezoelectric actuator of flexural vibration mode.
The former can change the volume of the pressure generating chamber by abutting an end surface of the piezoelectric element against the vibration plate, and manufacturing of a head suitable to high density printing is enabled. On the contrary, a difficult process, in which the piezoelectric element is cut and divided into a comb teeth shape to make it coincide with an array pitch of the nozzle orifices, and the operation of positioning and fixing the cut and divided piezoelectric element onto the pressure generating chamber are required, thus there is the problem of a complicated manufacturing process.
On the other hand, in the latter, the piezoelectric element can be fabricated and installed on the vibration plate by a relatively simple process, in which a green sheet as a piezoelectric material is adhered while fitting a shape thereof to the shape of the pressure generating chamber and is sintered. However, a certain size of vibration plate is required due to the usage of flexural vibration, thus there is the problem that a high density array of the piezoelectric elements is difficult.
Meanwhile, in order to solve such a disadvantage of the latter recording head, as shown in Japanese Patent Laid-Open No. Hei 5 (1993)-286131, a recording head is proposed, in which an even piezoelectric material layer is formed over the entire surface of the vibration plate by film deposition technology, the piezoelectric material layer is cut and divided into a shape corresponding to the pressure generating chamber by a lithography method, and the piezoelectric element is formed so as to be independent for each pressure generating chamber.
According to this, the operation of adhering the piezoelectric element onto the vibration plate is not required, and thus there is the advantage that not only the piezoelectric element can be fabricated and installed by accurate and simple means, that is, the lithography method, but also the thickness of the piezoelectric element can be thinned and a high-speed drive thereof is enabled.
Moreover, in such an ink-jet printing head, since the pressure generating chamber is formed so as to penetrate in the thickness direction of the head by performing etching to a plate from the surface opposite that having the piezoelectric element made thereon, a pressure generating chamber having a high dimensional accuracy can be arranged relatively easily with high density.
However, in such an ink-jet recording head, when a relatively large plate having a diameter of, for example, about 6 to 12 inches is to be used as the plate forming the pressure generating chamber, the thickness of the plate cannot help being thickened due to the problem of handling and the like, and accompanied with this, the depth of the pressure generating chamber is deepened. For this reason, if the thickness of a compartment wall partitioning the pressure generating chambers is not thickened, a sufficient rigidity is not obtained, thus there are problems that cross talk occurs, a desired ejection characteristic is not obtained, and so on. If the thickness of the compartment wall is thickened, nozzles cannot be arrayed in a high array density, thus there is the problem that printing quality with high resolution cannot be achieved.
On the other hand, in the piezoelectric actuator of the longitudinal vibration mode, a structure is conceived, in which the wide width portion is provided on the vibration plate side of the pressure generating chamber, the width of portions other than the wide width portion of the pressure generating chamber is reduced, and the thickness of the compartment walls is increased. In this case, however, an operation such as processing and pasting for the wide width portion of the pressure generating chamber is required, thus causing problems on operationality and accuracy.
In consideration of the foregoing circumstances, the object of the present invention is to provide an ink-jet recording head, in which the rigidity of the compartment wall is improved, the pressure generating chambers can be arranged in a high density, and cross talk between each pressure generating chamber is reduced, and to provide a manufacturing method of the same and an ink-jet recording apparatus.
DISCLOSURE OF THE INVENTION
A first aspect of the present invention for solving the above-described problems is an ink-jet recording head, which comprises: a passage-forming substrate having a silicon layer consisting of single crystal silicon, in which a pressure generating chamber communicating with a nozzle orifice is defined; and a piezoelectric element for generating a pressure change in the pressure generating chamber, the piezoelectric element being provided on a region facing the pressure generating chamber via a vibration plate constituting a part of the pressure generating chamber, characterized in that the pressure generating chamber is formed so as to open to one surface of the passage-forming substrate and not to penetrate there through, at least one bottom surface of the inner surfaces of the pressure generating chamber, the bottom surface facing to the one surface, is constituted of an etching stop surface as a surface in which anisotropic etching stops, and the piezoelectric element is provided on the one surface side of the passage-forming substrate by a film formed by film deposition technology and a lithography method.
In the first aspect, since the pressure generating chamber is formed without penetrating through the passage-forming substrate, the rigidity of the compartment wall partitioning the pressure generating chamber is maintained, crosstalk is restrained, and the ink-jet recording head having nozzle orifices in a high density can be mass-manufactured relatively readily.
A second aspect of the ink-jet recording head of the present invention according to the first aspect is characterized in that a piezoelectric layer constituting a part of the piezoelectric element has crystal subjected to priority orientation.
In the second aspect, crystal is subjected to priority orientation as a result of depositing the piezoelectric layer in a thin film step.
A third aspect of the ink-jet recording head of the present invention according to the second aspect is characterized in that the piezoelectric layer has crystal formed in a columnar shape.
In the third aspect, crystal is formed in a columnar shape as a result of depositing the piezoelectric layer in the thin film step.
A fourth aspect of the ink-jet recording head of the present invention according to any one of the first to third aspects is characterized in that the passage-forming substrate consists only of the silicon layer.
In the fourth aspect, the pressure generating chamber is defined only with the silicon layer.
A fifth aspect of the ink-jet recording head of the present invention according to the fourth aspect is characterized in that the passage-forming substrate consists of single crystal silicon of plane orientation (110), and the plane (110) formed by half etching which becomes the etch
Kamei Hiroyuki
Matsuzawa Akira
Miyata Yoshinao
Nishiwaki Tsutomu
Shimada Masato
Seiko Epson Corporation
Sughrue & Mion, PLLC
Vo Anh T. N.
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