JP3564853B2 - Method of manufacturing ink jet head and printer using the head - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ink-jet head used in an ink-jet recording apparatus that prints by discharging ink droplets onto paper or the like, a method for manufacturing the same, and an ink-jet printer having the ink-jet head.
[0002]
[Prior art]
2. Description of the Related Art In recent years, inkjet recording apparatuses have been required to perform printing at higher resolution and at higher speed. In order to meet this demand, for example, an ink jet recording apparatus as disclosed in Japanese Patent Application Laid-Open No. 7-96605 has been proposed. In this ink jet recording apparatus, in order to form a pressure chamber for pressurizing and discharging ink, a penetrating portion is formed by wet anisotropic etching with an alkaline solution from both sides of a single crystal Si substrate having a (110) plane orientation. This Si substrate is used as a spacer. The three-dimensional shape obtained by processing the Si substrate by etching has high precision, and therefore, an inkjet recording apparatus capable of obtaining high-definition printing was obtained.
[0003]
[Problems to be solved by the invention]
However, in the above-described method of forming the penetrating portion by wet anisotropic etching with an alkaline solution according to the related art, the wall between the adjacent pressure chambers necessarily has a plate having the same width as the thickness of the used Si substrate. When pressure is applied to the ink in the pressure chamber formed of the penetrating portion to discharge the ink, the wall may be deformed due to insufficient rigidity, and the ink discharge in high-frequency driving may not be stable. is there. In order to increase the nozzle density by reducing the width of the pressure chamber in response to the demand for higher definition and high-speed printing, the thickness of the wall must also be reduced. As the speed is increased, the rigidity of the wall is reduced, and the high-speed ejection characteristics when ejecting minute ink droplets are rather deteriorated.
[0004]
Therefore, the present invention solves the above-mentioned problems, and the object is to provide a high-definition and high-speed printing ink jet recording apparatus having high rigidity of an ink flow path and high-frequency ejection of minute ink droplets. The present invention is to provide an ink jet head capable of performing the following. It is another object of the present invention to provide an inexpensive ink jet head capable of discharging fine ink droplets at high frequency.
[0005]
[Means for Solving the Problems]
An ink jet head according to the present invention is an ink jet head including a Si substrate in which an ink cavity, an ink reservoir, and a supply path connecting the ink cavity and the ink reservoir are formed. It is characterized by being formed by etching with an alkali solution after etching.
[0006]
Further, in an ink jet head including a Si substrate having an ink cavity, an ink reservoir, a supply path connecting the ink cavity and the ink reservoir, and a nozzle for discharging ink, the ink cavity is formed by the Si substrate. Is processed by dry etching from one surface of the Si substrate to a predetermined depth, a nozzle for ink discharge is processed from the other surface of the Si substrate to a position corresponding to the ink cavity, and the ink cavity and the ink cavity The nozzle is characterized by being in communication with the nozzle, and the nozzle is processed by dry etching.
[0007]
Further, the Si substrate is a single crystal Si having a (110) plane orientation.
[0008]
The method of manufacturing an ink jet head according to the present invention is characterized in that a dry etching method of the ink cavity or the ink cavity and the nozzle is a TM method.
[0009]
In addition, the present invention is an ink jet printer having the above ink jet head.
[0010]
The TM method (time-modulated method) is a method for obtaining a structure with a high aspect ratio in dry etching, and is used to protect the side wall of a concave portion processed by etching during etching. This is an etching process in which a cycle for generating chemical species (radicals, ions, etc.) that cause a reaction and a cycle for depositing a protective film for protecting the side wall are alternately performed (see “Semiconductor Dry Etching Technology”). On page 336). By using this TM method, the side wall of the ink cavity and the nozzle can be processed perpendicularly to the surface of the Si substrate, so that an optimum shape can be formed with respect to the ink discharge characteristics. Further, in the method of manufacturing an ink jet head according to the present invention, after processing the ink cavity from one surface of the Si substrate to a predetermined depth by dry etching using a TM method, the Si substrate is treated with an alkali etching solution. It is characterized by the following.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, one embodiment (first embodiment) of the present invention will be described in detail.
[0012]
FIG. 1 is a perspective view of a main part of an ink jet head according to a first embodiment of the present invention, and shows a partial cross section. The ink jet head in this embodiment is an Si substrate 1 having an ink cavity 3 machined perpendicular to the surface of the Si substrate 1, an ink reservoir 5, and a supply path 4 communicating the ink cavity 3 and the ink reservoir 5. And the nozzle plate 2 on which the nozzles 6 are formed. The Si substrate 1 is made of (110) oriented single crystal Si.
[0013]
FIG. 2 shows a manufacturing process diagram of the ink jet head shown in FIG. A heat treatment is performed on the Si substrate 1 having a thickness of 150 μm for 4 hours in an atmosphere containing water vapor at 1100 ° C. to form thermal oxide films 7.8 on both surfaces of the Si substrate 1 (FIG. 2A). Next, a pattern corresponding to the ink cavity 3, the supply path 4, and the ink reservoir 5 is formed on the thermal oxide film 7 by photoetching. At this time, in the pattern corresponding to the ink cavity 3 and the ink reservoir 5, the thermal oxide film 7 is entirely removed, while in the pattern corresponding to the supply path 4, the thermal oxide film 7 has a total thickness of 1.5 μm. Etching is performed to leave a micron to form a thermal oxide film 7a (FIG. 2B), which is based on the method disclosed by the present applicant in Japanese Patent Application Laid-Open No. 5-62964. Next, dry etching is performed on the side of the thermal oxide film 7 of the Si substrate 1 by the TM method, and the ink cavity 3 and the ink reservoir 5 are formed by etching until penetrating the Si substrate 1 (FIG. 2 ( c)). Sulfur hexafluoride was used as an etching gas in the TM method, and carbon tetrachloride was used as a gas for depositing the side wall protective film. These gases were alternately supplied to a dry etching apparatus to form deep vertical holes in the Si substrate 1. Can be formed. In the above dry etching, the etching rate ratio (selectivity) between the Si substrate 1 and the thermal oxide film 7 is about 200, and the thickness of the thermal oxide film 7 at the time when the dry etching is completed is about The thickness of the thermal oxide film 7a of the pattern corresponding to the supply path 4 is about 0.75 microns. Next, the Si substrate 1 is treated with a hydrofluoric acid-based etchant under such conditions that the thermal oxide film 7a can be removed exactly (FIG. 2D), and then the Si substrate 1 is placed on the thermal oxide film 7 side. On the other hand, dry etching is further performed by the TM method to form a supply path 4 having a depth of 50 microns (FIG. 2E). Finally, the Si substrate 1 is treated with a hydrofluoric acid-based etchant to remove all of the thermal oxide films 7 and 7a and 8 (FIG. 2 (f)). The nozzle plate 2 on which the discharge nozzles 6 are formed is joined and assembled together with actuators and other components (not shown) to complete the ink jet head. In this embodiment, a small ink cavity 3 in which the area of a wall between adjacent pressure chambers is drastically reduced as compared with a conventional ink jet head is formed by performing dry etching on a Si substrate 1 by a TM method. Therefore, an ink jet head having high ink flow path rigidity can be provided. Due to the high rigidity of the ink flow path, it was possible to provide an ink jet head which has a small deformation of the ink flow path due to an input from the actuator, that is, has a high response frequency and can discharge ink at high speed. In the ink jet head of this embodiment, the characteristics of ink ejection (ink drop weight, ink ejection speed, etc.) were stable at frequencies up to 10 kHz. Further, in this embodiment, single crystal Si having a (110) plane orientation was used as the Si substrate. However, even if single crystal Si having another plane orientation, for example, a (100) or (111) plane orientation, was used. The effect obtained is exactly the same.
[0014]
Next, another embodiment (second embodiment) of the present invention will be described in detail.
[0015]
FIG. 3 is a perspective view of a main part of an ink jet head according to a second embodiment of the present invention, showing a partial cross section. As shown in FIG. 3, the ink jet head according to the present embodiment has an ink cavity 3b processed perpendicular to the surface of the Si substrate 1b, an ink reservoir 5b, and a supply path communicating the ink cavity 3b and the ink reservoir 5b. 4b, a Si substrate 1b on which an ink discharge nozzle 6b corresponding to each ink cavity 3b is formed, and a component (not shown) such as an actuator. The Si substrate 1b is composed of (110) Plane orientation single crystal Si. FIG. 4 shows a manufacturing process of the ink jet head shown in FIG. As in the case of the first embodiment of the present invention, thermal oxide films 7b and 8b are formed on both surfaces of a Si substrate 1b having a thickness of 150 microns (FIG. 4A), and then ink cavities are formed in the thermal oxide film 7b. A pattern corresponding to the nozzle 3b, the supply path 4b and the ink reservoir 5b, and a pattern corresponding to the nozzle 6b are formed on the thermal oxide film 8b (FIG. 4B). At this time, the formation of the pattern corresponding to the ink cavity 3b, the supply path 4b, and the ink reservoir 5b is performed in exactly the same steps as in the case of the above-described first embodiment of the present invention, that is, the ink cavity 3b and the ink reservoir 5b. In the pattern corresponding to 5b, the entire thermal oxide film 7b is removed, while in the pattern corresponding to the supply path 4b, etching is performed so as to leave 1 micron of the total thickness of 1.5 micron of the thermal oxide film 7b. And a thermal oxide film 7c (FIG. 4B). Next, dry etching is performed on the side of the thermal oxide film 8b of the Si substrate 1b by the TM method in the same manner as in the first embodiment of the present invention, thereby forming a recess having a depth of 20 μm to become the nozzle 6b ( FIG. 4 (c)). Next, the dry etching process and the hydrofluoric acid-based etchant process on the thermal oxide film 7b side of the Si substrate 1b are performed in the same manner as in the first embodiment of the present invention, so that the ink cavity 3b, the supply path 4b, and the ink reservoir 3b are formed. 5b are formed, and the depth of the ink cavity 3b and the ink reservoir 5b is set to 135 microns (FIG. 4D). As a result, when forming the ink cavity 3b, the bottom surface of the concave portion that is to be the nozzle 6b already formed penetrates, and the ink cavity 3b communicates with the nozzle 6b. Finally, the entire Si substrate 1b is immersed in a hydrofluoric acid-based etching solution to remove the thermal oxide films 7b, 7c and 8b (FIG. 4E), and the Si substrate 1b and components such as actuators (not shown) are separated. Assembly, the inkjet head is completed. In this embodiment, by performing dry etching on both surfaces of the Si substrate 1b by the TM method, the area of the wall portion between the adjacent pressure chambers on the same Si substrate 1b is greatly reduced as compared with the conventional inkjet head. The small ink cavity 3b and the nozzle 6b corresponding to the ink cavity 3b can be formed, so that an ink jet head having high ink channel rigidity can be provided. Due to the high rigidity of the ink flow path, it was possible to provide an ink jet head in which the deformation of the ink flow path due to the input from the actuator was small, that is, the response frequency was high, and the ink could be discharged stably at high speed. Actually, in the ink jet head according to the present embodiment, each characteristic of ink ejection (ink droplet weight, ink ejection speed, etc.) was stable at frequencies up to 10 kHz. Further, in this embodiment, since the individual ink cavities 3b and the corresponding nozzles 6b could be aligned in the photo step without using another component having the nozzles 6b formed therein, the normal process was employed. Compared to the assembly process using a jig, high-accuracy positioning can be easily achieved, and the number of parts and the assembly process can be reduced. That is, a high-quality inkjet head can be provided at low cost. We were able to. Further, in this embodiment, single crystal Si having a (110) plane orientation was used as the Si substrate. However, even if single crystal Si having another plane orientation, for example, a (100) or (111) plane orientation, was used. The effect obtained is exactly the same.
[0016]
Next, still another embodiment (third embodiment) of the present invention will be described in detail.
[0017]
FIG. 5 is a perspective view of a main part of an ink jet head according to a third embodiment of the present invention, showing a partial cross section. As shown in FIG. 5, the ink jet head according to the present embodiment has an ink cavity 3d processed perpendicularly to the surface of the Si substrate 1d, an ink reservoir 5d, and a supply path communicating the ink cavity 3d and the ink reservoir 5d. 4d, an Si substrate 1d on which ink discharge nozzles 6d corresponding to the respective ink cavities 3d are formed, and a component (not shown) such as an actuator, which is assembled by assembling the (110) Si substrate. Plane orientation single crystal Si. FIG. 6 shows a manufacturing process of the ink jet head shown in FIG. As in the case of the first embodiment of the present invention, thermal oxide films 7d and 8d are formed on both surfaces of a Si substrate 1d having a thickness of 150 microns (FIG. 6 (a)). A pattern corresponding to 3d, supply path 4d, and ink reservoir 5d is formed, and a pattern corresponding to nozzle 6d is formed in thermal oxide film 8d. At this time, the formation of the pattern corresponding to the ink cavity 3d, the supply path 4d, and the ink reservoir 5d is performed in exactly the same steps as in the first embodiment of the present invention, that is, the ink cavity 3d and the ink reservoir 5d. In the pattern corresponding to (1), all of the thermal oxide film 7d is removed, whereas in the pattern corresponding to the supply path 4d, etching is performed so as to leave 1 micron of the total thickness 1.5 μm of the thermal oxide film 7d. The thermal oxide film 7e is used. Similarly, a pattern corresponding to the nozzle 6d formed on the thermal oxide film 8d is also etched to leave 1 micron of the total thickness of 1.5 microns of the thermal oxide film 8d to form a thermal oxide film 8e (FIG. 6 (b)). Next, dry etching is performed by the TM method on the side of the thermal oxide film 8d of the Si substrate 1d in the same manner as in the first embodiment of the present invention, and a concave portion having a depth of 135 microns to become the ink cavity 3d and the reservoir 5d. (FIG. 6 (c)), and then dipping the Si substrate 1d in a hydrofluoric acid-based etching solution and performing etching to just remove the thermal oxide film 7e corresponding to the supply path 4d (FIG. 6 (d)). )). Next, a supply path 4d having a depth of 50 microns is formed by performing etching with an alkaline etching solution. At this time, the bottom of the concave portion to become the ink cavity 3d is also etched, and the Si substrate 1d made of the (111) crystal plane is formed. Two slopes 9 forming an angle of 35 degrees with the surface are formed (FIG. 6E). Next, the Si substrate 1d is immersed in a hydrofluoric acid-based etchant, and etching is performed to just remove the thermal oxide film 8e corresponding to the nozzle 6d (FIG. 6 (f)). Next, dry etching is performed on the surface of the Si substrate 1d where the thermal oxide film 8d is formed until a concave portion to be the nozzle 6b penetrates (FIG. 6 (g)). Finally, the entire Si substrate 1d is immersed in a hydrofluoric acid-based etching solution to remove the thermal oxide films 7d, 7e and 8d (FIG. 6 (h)), and the Si substrate 1d and components (not shown) such as actuators are separated. Assembly, the inkjet head is completed. In this embodiment, by performing dry etching on both surfaces of the Si substrate 1d by the TM method, the area of the wall portion between the adjacent pressure chambers on the same Si substrate 1d as compared with the conventional inkjet head is drastically reduced. The small ink cavities 3d and the nozzles 6d corresponding to the ink cavities 3d can be formed, so that an ink jet head having high ink flow path rigidity can be provided. Due to the high rigidity of the ink flow path, it was possible to provide an ink jet head in which the deformation of the ink flow path due to the input from the actuator was small, that is, the response frequency was high, and the ink could be discharged stably at high speed. Actually, in the ink jet head according to the present embodiment, each characteristic of ink ejection (ink droplet weight, ink ejection speed, etc.) was stable at frequencies up to 10 kHz. Further, in the present embodiment, the positioning of each ink cavity 3d and the corresponding nozzle 6d could be performed in the photo process without using another component having the nozzle 6d formed thereon. The reduction in the number of points and the number of assembling steps can be realized, that is, an inexpensive high-quality inkjet head could be provided. Further, by making the bottom surface of the ink cavity 3d the inclined surface 9, it was possible to improve the discharging property of the bubbles generated in the ink.
[0018]
【The invention's effect】
As described above, according to the present invention, there is provided an ink jet head including a Si substrate in which an ink cavity, an ink reservoir, and a supply path connecting the ink cavity and the ink reservoir are formed as a constituent member. By forming a hole in the Si substrate by dry etching, it is possible to process a highly rigid ink cavity in which the area of the wall between adjacent pressure chambers is drastically reduced as compared with a conventional inkjet head, It is possible to provide an ink-jet head and an ink-jet printer which have a high response frequency, can discharge fine ink stably at high speed, that is, have high print quality.
[0019]
Further, according to the present invention, an ink jet head with high print quality can be provided by forming a nozzle with high positioning accuracy by a photo process at a position corresponding to the ink cavity.
[0020]
Further, according to the present invention, a bubble is discharged by forming a slope on the bottom surface of the ink cavity and the ink cavity by dry etching and anisotropic etching using an alkaline solution using a (110) plane oriented Si substrate. It is possible to provide an ink jet head having excellent printing properties and high printing quality.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a partial cross section of an inkjet head according to an embodiment of the present invention.
FIG. 2 is a manufacturing process diagram of an inkjet head according to an embodiment of the present invention.
FIG. 3 is a perspective view showing a partial cross section of an inkjet head according to another embodiment of the present invention.
FIG. 4 is a manufacturing process diagram of an inkjet head according to another embodiment of the present invention.
FIG. 5 is a perspective view showing a partial cross section of an ink jet head according to another embodiment of the present invention.
FIG. 6 is a manufacturing process diagram of an ink jet head according to another embodiment of the present invention.
[Explanation of symbols]
1, 1b, 1d Si substrate 2 Nozzle plate 3, 3b, 3d Ink cavity 4, 4b, 4d Supply path 5, 5b, 5d Ink reservoir 6, 6b, 6d Nozzle 7, 7a, 7b Thermal oxide film 7c, 7d, 7e Thermal oxide film 8, 8b, 8d, 8e Thermal oxide film 9 Slope

Claims (3)

In a method for manufacturing an ink jet head, which is used in an ink jet recording apparatus and has an ink cavity, an ink reservoir, and a Si substrate on which a supply path connecting the ink cavity and the ink reservoir is formed,
A method of manufacturing an ink-jet head , comprising: forming the ink cavity from one surface of the Si substrate to a predetermined depth by dry etching using a TM method, and then forming the Si substrate by etching with an alkali solution. . 2. The method according to claim 1, wherein the Si substrate is a single crystal Si having a (110) plane orientation. An inkjet printer having an inkjet head manufactured by the method according to claim 1.

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