JPH04312852A - Ink jet printing head and its manufacture - Google Patents

Abstract

PURPOSE:To achieve the production of a thin oscillation film which constitutes a part opposed to a pressure chamber at an ink jet printing head with a piezoelectric element provided on the oscillation film which constitutes a part of the inner wall surface of the pressure chamber communicating with an orifice, with high productivity. CONSTITUTION:A thin film 17 containing a silicone thermal oxide film is formed on the surface of a flat plate-like support 16 of single crystal silicone using thermal oxidation technique. Next, a recessed hole 21 which reaches the rear surface of the thin film layer 17 is opened by performing crystal surface aerotropic etching process on the support 16 from the rear using an etching material which does not act on the layer 17. The thin film layer 17 located above the recessed hole 21 is used as an oscillation film 22.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-demand type inkjet printer head and a manufacturing method.

0002

2. Description of the Related Art Currently, inkjet printer heads, which eject ink droplets from an orifice and fix them onto printing paper, are in practical use as printer heads capable of silent, high-density printing. For example, in an on-demand type inkjet printer head, a vibrating membrane that can freely vibrate in a direction perpendicular to the surface is formed as a part of the inner wall surface of a pressure chamber that communicates with each of the orifices arranged in an array.
It has a structure in which a piezoelectric element that operates according to drive power is provided on this vibrating membrane. In such an inkjet printer head, the piezoelectric element vibrates together with the vibrating membrane when driving power corresponding to the print image is supplied, and the pressure generated by this vibration causes the ink in the pressure chamber to be ejected as ink droplets from the orifice. There is.

[0003] In such an inkjet printer head, there is a demand for a thinner vibrating membrane in order to save power and improve responsiveness. 61-2
This method has been proposed in Japanese Patent No. 025, Japanese Patent Publication No. 62-22790, etc.

First, in an inkjet printer head 1 disclosed in Japanese Patent Publication No. 61-2025, as illustrated in FIG. A second plate 5 made of a glass substrate or the like is integrally joined onto the plate 4, and an arc-shaped groove 6 is formed on the surface of the second plate 5 by etching, cutting, etc.
The layer thickness of the part facing the pressure chamber 3 is 50 (μ
The vibrating membrane 7 has a structure in which a piezoelectric element 8 is mounted on the surface of each vibrating membrane 7.

Furthermore, in the inkjet printer head 9 disclosed in Japanese Patent Publication No. 62-22790, as illustrated in FIG. After forming the electrode 12 on the vibrating membrane 11, PZT (Lea
The piezoelectric element 13 has a structure in which the piezoelectric element 13 is formed by printing powder of Zirco Titanate (Zirco Titanate) by adding a binder to form a paste.

In the above-mentioned inkjet printer heads 1 and 9, the thin vibrating membranes 7 and 11 formed on the portions of the second plates 5 and 10 facing the pressure chambers 3 vibrate well, resulting in power saving and Responsiveness can be improved, and since the parts of the second plates 5, 10 other than the vibrating membranes 7, 11 are thick, strength is also ensured.

[0007]

[Problems to be Solved by the Invention] The inkjet printer heads 1 and 9 as described above have a thin vibrating membrane 7 and 11 formed in the portion facing the pressure chamber 3, thereby reducing power consumption and improving responsiveness. In addition to achieving this, strength is also ensured.

Here, the above-mentioned Japanese Patent Publication No. 61-2025 discloses that the vibrating membrane 7 of the inkjet printer head 1 is
Although it is described that the second plate 5 is formed by etching or cutting the second plate 5 made of a glass substrate or the like, in reality, by controlling the etching time and mechanical precision processing, the layer thickness is uniformly 50 (μm). It is extremely difficult to form a vibrating membrane 7 of this type.

Further, in the above-mentioned Japanese Patent Publication No. 62-22790, the thickness of the second plate 10 made of glass, stainless steel, etc. of the inkjet printer head 9 is partially 50 to 100 (μm), and the vibrating membrane is 11, but a specific method for manufacturing this vibrating membrane 11 is not disclosed.

In other words, when the above-described inkjet printer heads 1 and 9 are implemented, the layer thickness of the vibrating membranes 7 and 11 becomes uneven and thinning is incomplete, resulting in problems in power saving and response. There is a concern that print quality may deteriorate as a result. For this reason, there is a need for a method for easily forming partially thin vibrating membranes 7, 11 on second plates 5, 10.

[0011]

[Means for solving the problem] The invention according to claim 1 includes:
Orifices are arranged in an array to eject ink droplets onto the printing medium, and a vibrating membrane that can freely vibrate in a direction perpendicular to the surface is formed as part of the inner wall surface of a pressure chamber that communicates with each orifice. In an inkjet printer head in which a piezoelectric element that operates according to driving power is provided on the vibrating membrane, a flat plate made of single-crystal silicon in which concave holes are formed by crystal plane anisotropic etching using a selective etching material is used. A support was provided, and a vibrating membrane was formed on the surface of the support at a portion located above the recessed hole of a silicon thermal oxide film formed by thermal oxidation processing.

[0012] In the invention as claimed in claim 2, orifices are arranged in an array and each discharges an ink droplet onto a printing medium, and a surface is formed as a part of the inner wall surface of a pressure chamber that communicates with each of the orifices. In an inkjet printer head, a vibrating membrane is formed that can freely vibrate in orthogonal directions, and a piezoelectric element that operates according to driving power is provided on the vibrating membrane.
A silicon thermal oxide film is formed on the surface of a flat support made of single crystal silicon by thermal oxidation processing, and crystal plane anisotropic etching is performed on the support from the back side using an etching agent that does not act on the silicon thermal oxide film. A recessed hole reaching the back surface of the silicon thermal oxide film was formed by doing this, and the silicon thermal oxide film located on the recessed hole was used as at least a part of the vibrating part to form a piezoelectric element and a pressure chamber.

[0013]

[Operation] A silicon thermal oxide film is formed on the surface of a flat support made of single crystal silicon by thermal oxidation processing, and an etching material that is not used for this silicon thermal oxide film is used to change the crystal plane from the back side of the support. By performing directional etching to form a recess that reaches the back surface of the silicon thermal oxide film, and forming a piezoelectric element and a pressure chamber using the silicon thermal oxide film located above the recess as at least a part of the vibrating part. By using selective etching, an inkjet printer head with a uniform vibrating membrane layer thickness can be produced with good productivity.

[0014]

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 to 4. First, this inkjet printer head 1
4, as illustrated in FIG. 1, a thin film layer 17 including a silicon thermal oxide film, a lower electrode 18, and an electromechanical conversion film 19 are formed on the surface of a flat support 16 with a mask 15 attached to the back surface. The electromechanical transducer film 19 is uniformly layered, and an upper electrode 20 is formed in a predetermined pattern on the electromechanical transducer film 19. Here, a recessed hole 21 whose back side is enlarged is formed in the support body 16, and the thin film layer 17 located on this recessed hole 21 serves as a vibrating membrane 22. Furthermore, due to the members 18 to 20 located on the vibrating membrane 22,
A piezoelectric element 23 is formed that vibrates in accordance with applied voltage.

[0015] Then, Si is deposited on the thin film members 19 and 20.
A flat orifice plate 25 is attached on the protective film 24 laminated with O2 or the like, and as illustrated in FIG. 26, an orifice 27 extending from the pressure chamber 26 to the front edge, an ink supply path 29 communicating the pressure chamber 26 and the ink tank 28, and the like are formed by grooves in a predetermined pattern.

A method of manufacturing the inkjet printer head 14 having such a structure will now be described with reference to FIG. 3. First, as illustrated in figure (a), the plate thickness is 0.1~
Both sides of the support 16 made of flat single-crystal silicon with a thickness of 0.5 (mm) are coated with several thousand (Å) to 3.0 (μ) by thermal oxidation processing.
silicon thermal oxide film (SiO2) 30 with a film thickness of about m),
Form 31. Next, in order to improve the strength of the silicon thermal oxide film (SiO2) 30 that will become the mask 15, LPCVD (Low Pr) is applied on the silicon thermal oxide film 30.
essure-Chemical VaporDep
By forming silicon nitride (Si3N4) by the
In order to ensure a film thickness of , a thin film layer 17 that becomes the vibrating membrane 22 may be formed by laminating a thin film layer 32 such as a silicon oxide film having the same composition on the silicon thermal oxide film 31 . For example, the thin film layer 32 such as a silicon oxide film is formed by coating and baking a SiO2-based film forming coating liquid by a spinner method, dipping method, spraying method, brush coating method, etc.
It is laminated on the thin film layer 17 with a film thickness of ~50 (μm).

Next, as illustrated in FIG. 3C, the silicon thermal oxide film 30 is patterned using an existing thin film process to form a mask 15, and etching is performed from above the mask 15 without affecting the thin film layer 17. Crystal plane anisotropic etching is performed on the support 16 using a liquid. Then, as illustrated in FIG. 2(d), the support 1 is
6 is formed with a pyramidal recessed hole 21 corresponding to the thickness of the plate, and the formation of this recessed hole 21 stops at the thin film layer 17.

[0018] Here, the above-mentioned crystal plane anisotropic etching will be specifically explained. First, KOH, N2H2 (
Alkaline aqueous solutions such as hydrazine), NH2 (CH2)2-NH2 (ethylenediamine), and NH4OH (ammonia water) are used, and CH3・CHOH・CH3 (isopropanol) and C6H4(OH)2 (pyrocatechol) are used.
Alcohol such as alcohol is used as a buffer material. For example, when single crystal silicon is etched with an aqueous solution of ethylenediamine and pyrocatechol, its (100) plane and (1
10) Since the etching rates for the (111) plane and the (111) plane are 50, 30, and 3 (μm/h), respectively, the (100)
For a flat wafer, etching proceeds at an angle of 54.7 degrees and stops at a depth corresponding to the pattern width.

Furthermore, in this inkjet printer head 14, the layer on the support 16 side of the thin film layer 17 forming the vibrating membrane 22 is a thin film layer deposited from the single crystal silicon support 16 by thermal oxidation processing. Adhesion to the support 16 is extremely good compared to thin film layers laminated by vapor deposition or the like. Therefore, as described above, the support 16 and the thin film layer 17 are formed by the recessed hole 21 formed by crystal plane anisotropic etching.
Even if the interface with the material is exposed, there will be no peeling or the like.

Furthermore, as described above, the pyramidal recessed hole 21 formed in the support 16 by crystal plane anisotropic etching has good shape accuracy and uniformity, so that the portion of the thin film layer 17 other than the vibrating membrane 22 is is supported by the support body 16 and has good strength, which can contribute to improving the durability of the inkjet printer head 14.

Therefore, the thin film layers 18 to 20, 24 are sequentially laminated using the existing thin film process. For example, each electrode 18, 20 is made of metal such as Al or Ti or ITO (
It is formed of a transparent conductive material such as an indium-tin oxide (Indium-Tin Oxide) layer.

In addition, in this inkjet printer head 14, the electromechanical transducer film 19 is formed by a melt epitaxy method, a sol-gel method, a precipitation reaction method, an anodic reaction method, chemical plating, etc.
By forming , the uniformity of the chemical composition is improved by precipitation from the liquid phase. In other words, when a thin film layer is precipitated from the liquid phase in this way, it is possible to control the particle morphology well, as well as the amount of addition of different elements and the uniformity of the distribution, so that the properties are uniform. The performance is also stable, and the growth rate is faster than that of sputtering methods. For example, from the liquid phase to the electromechanical conversion film 1
In the sol-gel method, which is one of the methods for forming 9, a sol is generated by inducing hydrolysis by adding water, acid, or alkali to a homogeneous solution having a predetermined chemical composition. A gel is produced by dispersing fine particles of the desired composition in this sol by evaporating the solvent or cooling it.

An example of a specific manufacturing method for forming the electromechanical transducer film 19 made of a PZT film by the sol-gel method will be described in detail below. First, add 1.0 (ml) to 2.
Pb(CH3COO
) 2.3H2O is dissolved, dried at 105 degrees, and then cooled to 80 degrees. And here Zr(C3H7O)4 and Ti[(CH3
)2CHO]4 and were added sequentially and mixed by ultrasonication,
Coat this on the substrate using a spinner method and
A PZT film is formed by annealing at 0 degrees. In addition,
Other fabrication methods from such a liquid phase include Pb(O
It is possible to form the electromechanical transducer film 19 made of PbTiO3 by dipping a solution of Ac)2-Ti(OBu)4-based composite oxyalkoxide.

Furthermore, in this inkjet printer head 14, the orifice plate 25 is made of photosensitive glass or photosensitive resin, and has a diameter of 300 (μm).
) ~ 1.0 (mm) pressure chamber 26 and width 40 (μm)
The orifice 27 and the like are patterned as grooves with a depth of 40 (μm). Note that, as illustrated in FIG. 4, an inkjet printer head 36 in which the orifice plate 35 is formed in a two-part structure with two flat plates 33 and 34 can also be implemented. In this case, the orifice plate 35 has a structure in which, for example, a pressure chamber 26, an orifice 27, etc. are formed on a flat plate 33 made of photosensitive resin by optical patterning, and a flat plate 34 made of glass, stainless steel, etc. is bonded thereto. There is.

[0025]

Effects of the Invention As described above, the present invention forms orifices that are arranged in an array and each discharges ink droplets onto a printing medium, and as part of the inner wall surface of a pressure chamber that communicates with each of the orifices. In an inkjet printer head, a vibrating membrane is formed that can freely vibrate in a direction perpendicular to the surface, and a piezoelectric element that operates according to driving power is provided on the vibrating membrane. A silicon thermal oxide film is formed by oxidation processing, and a recessed hole reaching the back side of the silicon thermal oxide film is created by performing crystal plane anisotropic etching on the support from the back side using an etching material that does not act on the silicon thermal oxide film. By forming a piezoelectric element and a pressure chamber using the silicon thermal oxide film located on the recessed hole as at least a part of the vibrating part, a thin vibrating membrane is formed with selective etching, so that vibrations can be reduced. An inkjet printer head with a uniform layer thickness can be produced with good productivity, and the silicon thermal oxide film other than the vibrating membrane is supported by a support, which improves power saving and responsiveness of the inkjet printer head. This has the effect that it is possible to ensure good strength as well as improved properties, and it is possible to manufacture an inkjet printer head that has both printing performance and durability with good productivity.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view showing an embodiment of the present invention.

FIG. 2 is a plan view.

FIG. 3 is a process diagram showing a manufacturing method.

FIG. 4 is a longitudinal sectional front view showing a modification.

FIG. 5 is a plan view showing a first conventional example.

FIG. 6 is an exploded perspective view showing a second conventional example.

[Explanation of symbols]

14, 36 Inkjet printer head 16
Support body 21 Recessed hole 22 Vibration membrane 23 Piezoelectric element 26 Pressure chamber

Claims (2)

[Claims] 1. An orifice is arranged in an array to eject ink droplets onto a printing medium, and is a part of the inner wall surface of a pressure chamber that communicates with each of the orifices and is capable of vibrating in a direction perpendicular to the surface. In an inkjet printer head that forms a vibrating membrane and has a piezoelectric element that operates according to driving power on the vibrating membrane, single-crystal silicon in which concave holes are formed by crystal plane anisotropic etching using a selective etching material is used. An inkjet printer head characterized in that a flat plate-shaped support is provided, and the vibrating membrane is formed in a portion located on a recessed hole of a silicon thermal oxide film formed on the surface of the support by thermal oxidation processing. . 2. Orifices arranged in an array to eject ink droplets onto a printing medium are formed, and each of the orifices communicates with each of the orifices, and as part of the inner wall surface of the pressure chamber, it can vibrate in a direction perpendicular to the surface. In an inkjet printer head that has a vibrating membrane formed thereon and a piezoelectric element that operates according to driving power on the vibrating membrane, a silicon thermal oxide film is formed on the surface of a flat support made of single crystal silicon by thermal oxidation processing. A recessed hole reaching the backside of the silicon thermal oxide film is formed by performing crystal plane anisotropic etching on the support from the back side using an etching material that is not used for this silicon thermal oxide film, and this recessed hole is A method of manufacturing an inkjet printer head, characterized in that the piezoelectric element and the pressure chamber are formed by using the silicon thermal oxide film located above as at least a part of the vibrating film.