JP2003103778A - Ink-jet head and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet head capable of preventing bubble generation by forming a communication hole between a pressuring liquid chamber and a nozzle by both dry etching and wet etching, and further providing an inclined part in a connection part between the pressuring liquid chamber and the communication hole, and also by providing an inclined part in the nozzle connecting surface of the communication hole, and to provide a production method therefor. SOLUTION: An inclined part with the cross-section of the pressuring liquid chamber enlarged toward the communication hole is provided in a connection part between a pressuring liquid chamber and a communication hole in a pressuring liquid chamber forming member comprising the ink-jet head.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head and a method for manufacturing the same, and more particularly, to a processing technique for forming a fine shape on a silicon single crystal substrate having a crystal orientation, particularly a liquid chamber portion used for the ink jet head. The present invention relates to a processing technology and a processing shape of a silicon single crystal substrate that constitutes a.

[0002]

2. Description of the Related Art An ink jet recording apparatus has many advantages such as extremely low noise during recording, high speed printing, and use of plain paper which has a high degree of freedom of ink and is inexpensive. Among these, the so-called ink-on-demand method, which ejects ink droplets only when recording is necessary, is currently mainstream because it does not require recovery of ink droplets unnecessary for recording.

As a conventional ink jet head of the ink-on-demand system, Japanese Patent Publication No. 2-51734 is available.
Japanese Patent Laid-Open Publication No. 61-59911 proposes a method of driving a piezoelectric element as a driving means proposed in Japanese Patent Publication No. 61-59911 to generate bubbles and eject the ink at the pressure. There is a driving means proposed by Japanese Patent Publication No. -50601 which utilizes electrostatic force.
Among them, an ink jet head of a type in which a nozzle plate having a nozzle opening and a vibrating plate are adhered to both surfaces of a spacer to form a pressure chamber and the vibrating plate is deformed by a piezoelectric vibrator is used for ejecting ink droplets. Since heat energy is not used as a drive source, there is no change in the quality of the ink due to heat, and it is possible to eject color ink that is particularly prone to deterioration due to heat. Moreover, the amount of ink droplets can be adjusted by adjusting the variation of the piezoelectric vibrator. It is the optimum head for configuring a printer for high-quality color printing because it can be adjusted to.

On the other hand, in order to perform higher quality color printing using an ink jet head, higher resolution is required, so that the sizes of the piezoelectric vibrator and the partition walls of the spacer member are inevitably reduced, and the member High precision is required for processing and assembly of members. For this reason, component manufacturing technology using anisotropic etching of silicon single crystal substrate that can process fine shapes with high accuracy with a relatively simple method,
It has been considered to apply a so-called micromachining technology to the processing of the members that make up the inkjet head,
Various techniques and methods have been proposed. By the way, in order to print a color image or a character with high quality, not only the arrangement density of the nozzle openings is increased but also the printing in which the area of one dot itself is changed according to the image signal is required. For this purpose, it is necessary to reduce the amount of ink ejected once and to realize high-speed driving so that an ink jet head can eject ink drops a plurality of times for one pixel. For this purpose, it is necessary to first reduce the displacement amount of the piezoelectric vibrator and instantaneously reflect it as a volume change of the pressure generating chamber. Then, in order to connect a small volume change of the pressure generating chamber with the ejection of the ink droplet, it is necessary to reduce the pressure loss in the pressure generating chamber. It is important to increase the rigidity of the pressure generating chamber in order to efficiently link the displacement of the piezoelectric vibrator to the volume change of the pressure generating chamber.To reduce the pressure loss in the pressure generating chamber, it is important to increase the rigidity of the pressure generating chamber. Reducing the volume is an important issue. In order to reduce the volume of the pressure generating chamber, it is conceivable to reduce the opening area.However, considering the processing accuracy of the piezoelectric vibrator that abuts against this, the arrangement pitch of the nozzle openings will be the limit at the most. However, there is no choice but to adopt a method of reducing the volume by making the depth of the pressure generating chamber shallow.

[0005]

However, on the other hand, considering the handling of the spacer in the assembly process, the thickness of the silicon single crystal is required to be 300 μm or more. There is a problem that it will occur. Therefore, the pressure generating chamber can be formed shallower than the thickness of the silicon single crystal substrate by applying so-called half etching in which the silicon single crystal substrate is etched from only one surface thereof.
On the other hand, when a silicon single crystal substrate is used as a spacer, the nozzle plate is provided so as to face the pressure generating chamber, and the pressure generating chamber communicates with the surface on which the nozzle plate is provided in order to communicate the nozzle opening with the pressure generating chamber. It is necessary to form a penetrating portion for making the above. However, as is well known, in order to form the through portion by anisotropic etching, at least about 1.7 times the thickness of the silicon single crystal substrate (√
3) It is necessary to set the above opening length, and
The minimum length of the penetrating part is 510 when 0 μm or more is used.
It becomes about μm. In this case, not only the volume of the communication hole causes an increase in the volume of the pressure generating chamber, but also this communication hole has a thickness of the silicon single crystal substrate, that is, 300 μm and a longitudinal length of 510 μm, so that pressure is generated at high density. When the partition wall of the pressure generating chamber has to be thin as in the case of arranging the chambers, there is a problem that the rigidity of the partition wall decreases. In order to solve such a problem, it is considered that the communication hole is processed by a method other than wet etching, for example, laser processing or dry etching. However, laser processing or dry etching requires processing time.

The present invention is intended to solve these problems, in which a communicating hole between the pressurized liquid chamber and the nozzle is formed by both dry etching and wet etching, and the pressurized liquid chamber and the communicating hole are further formed. By providing an inclined portion at the connecting portion with the ink jet head, it is possible to prevent the generation of bubbles, and also by forming an inclined portion on the nozzle connection surface of the communication hole, it is possible to prevent the generation of bubbles. It is an object to provide a manufacturing method thereof.

[0007]

In order to solve the above problems, an ink jet head of the present invention comprises a nozzle forming member having a plurality of nozzles, a pressurized liquid chamber forming member communicating with the nozzles, and an electric machine. An actuator member that propagates the displacement of the conversion element to the ink conversion liquid chamber is provided, and the pressurized liquid chamber forming member has at least a pressurized liquid chamber and a communication hole that connects the pressurized liquid chamber and the nozzle. Has been formed. Further, the connecting portion between the pressurized liquid chamber and the communication hole in the pressurized liquid chamber forming member is provided with an inclined portion in which the cross section of the pressurized liquid chamber becomes larger toward the communication hole. Therefore, it is possible to provide a highly reliable ink jet head in which ink can flow from the pressurized liquid chamber to the communication hole without stagnation and a nozzle bit defect due to bubble generation does not occur.

Further, according to another aspect of the invention, an ink jet head is provided with a sloped portion at the joint between the communication hole and the nozzle in the pressurized liquid chamber forming member, the diameter of the communication hole increasing toward the nozzle. There is. Therefore, it is possible to provide a highly reliable inkjet head in which the ink flow from the end of the communication hole to the nozzle plate can be performed without stagnation and a nozzle bit defect due to bubble generation does not occur.

Further, it is desirable that the pressurizing liquid chamber forming member is made of silicon.

Further, according to another method of manufacturing an ink jet head, the resist pattern formed by patterning the pattern resist of the communicating hole communicating with the nozzle is not etched through the substrate by dry etching. It is characterized in that it has a step of performing a substantially parallelogram shape and a step of thereafter performing processing by anisotropic wet etching to form an inclined portion on the nozzle side and / or the ink conversion liquid chamber side of the communication hole. . Therefore,
Throughput is poor with dry etching alone, but throughput can be improved by using it together with wet etching, and ink flow to the pressurized liquid chamber and / or communication hole and / or communication hole and nozzle plate can be performed without stagnation. It is possible to provide an inkjet head manufacturing method capable of manufacturing a highly reliable inkjet head in which a nozzle bit defect due to bubble generation does not occur.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION At a connecting portion between a pressurized liquid chamber and a communicating hole in a pressurized liquid chamber forming member forming an ink jet head of the present invention, a slope in which a cross section of the pressurized liquid chamber becomes larger toward the communicating hole. Section is provided.

[0012]

1 is an exploded perspective view showing the overall construction of an ink jet head according to an embodiment of the present invention. In the figure, the ink jet head of the present embodiment has a nozzle plate 1
1, the flow path plate 12, the vibration plate 13, and the actuator plate 14 are included.

Further, a large number of nozzles 15 which are fine holes for ejecting ink droplets are formed on the nozzle plate 11 in correspondence with the tip portions of the pressurized liquid chambers, and the diameter of the nozzles is 20 to 20. It is 35 μm. The nozzle plate 11 uses, for example, a Ni metal plate manufactured by an electroforming method, but silicon or another metal material can be used. A water repellent surface treatment film is formed on the nozzle plate 11.

Further, the flow path plate 12 is made of silicon, and the plane orientation of the silicon substrate is (110). By using this (110) substrate, the pressurized liquid chamber can be formed perpendicularly to the nozzle pitch direction, which is advantageous for miniaturization and narrowing of the pitch. In this flow path plate 12, a communication hole 16 communicating with each nozzle hole 15, a pressurized liquid chamber 17, a common liquid chamber 18, and a common liquid chamber 18 to a pressurized liquid chamber 17
A communication path (not shown) is formed to communicate with the. The communication hole 16 communicating with each nozzle hole 15 is formed by, for example, a dry etching method and an anisotropic wet etching method. The pressurized liquid chamber 17 and the common liquid chamber 18 are formed by the Si anisotropic wet etching method. An oxide film is formed on the surface of the flow path plate 12. Due to the formation of the oxide film, it hardly elutes into the ink,
Further, since the wettability is also improved, the structure is such that bubbles do not easily accumulate. This is not limited to an oxide film, but a titanium nitride (TiN) film,
Alternatively, a polyimide film may be used.

The vibrating plate 13 is composed of a metal plate formed by the Ni electroforming method, and the vibrating function part of the vibrating plate 13 has a beam part 19 joined to a non-driving part in the piezoelectric element and a piezoelectric element in the piezoelectric element. It is composed of an island-shaped convex portion 20 joined to the driving portion, and a thinnest film portion 21 (diaphragm region) having a thickness of about 3 to 10 μm formed around the island-shaped convex portion 20.

Further, the actuator plate 14 has a plurality of laminated piezoelectric elements, which are electromechanical conversion elements, arranged in two rows on a ceramic substrate such as barium titanate, alumina, and forsterite. Join and
Each of these two rows of piezoelectric elements is cut by dicing. It should be noted that the plurality of piezoelectric elements in each column are alternately configured with a drive unit 22 that applies a drive waveform and a non-drive unit 23 that does not apply a drive waveform in the channel direction. Here, the piezoelectric element is a zirconate titanate (P
ZT) and silver paradium (AgPd) with a thickness of several μm / layer
And the internal electrodes made of are alternately laminated. Low-voltage driving is possible by using a laminated type piezoelectric element having a thickness of 10 to 50 μm / layer. The electromechanical conversion element is not limited to PZT. Then, the internal electrodes of the piezoelectric element are alternately taken out to the end face, and the common electrode pattern and the individual electrode pattern are used as the end face electrodes on one substrate and electrically connected to the end face electrode of the piezoelectric element serving as the driving unit through a conductive adhesive or the like. To the PC via the common electrode pattern and the FPC cable connected to the common electrode pattern.
By connecting to the B substrate and applying a driving waveform to the driving unit, a displacement in elongation in the stacking direction is generated.

FIG. 2 is a sectional view showing the structure of the flow path plate in the ink jet head of this embodiment. In the figure, the same reference numerals as those in FIG. 1 indicate the same components. The flow channel plate shown in FIG. 2A includes a common liquid chamber 18, a pressurized liquid chamber 17,
It is composed of a communication hole 16 that connects the pressurized liquid chamber and the nozzle.
The connecting portion between the pressurized liquid chamber 17 and the communication hole 16 is provided with an inclined portion 24 such that the cross section of the pressurized liquid chamber 17 becomes larger as it approaches the communication hole 16. Therefore, the structure is such that the ink flow does not stagnant. The flow path plate shown in FIG. 2B includes a common liquid chamber 18, a pressurized liquid chamber 17, and a communication hole 16 that connects the pressurized liquid chamber 17 and the nozzle 15. Communication hole 16
On the nozzle joint surface side of the communication hole 1 as it approaches the nozzle.
The inclined portion 25 is provided so that the diameter of 6 increases. By providing the nozzle 15 on the end of the inclined portion 25, the flow of ink does not stagnant. Also,
It has a structure with good bubble discharge. Therefore, it is possible to form a head of high quality and high reliability.

A method for manufacturing an ink jet head which is another invention will be described below. FIG. 3 shows a first invention of another invention.
6A and 6B are cross-sectional views showing the manufacturing process of the inkjet head according to the example of FIG. First, as shown in FIG.
A silicon substrate (110) 101 having a thickness of 00 μm is prepared, and a silicon oxide film 102 having a thickness of 1.0 μm and L having a thickness of 0.2 μm are prepared.
A P-CVD nitride film 103 was formed. Next, as shown in FIG. 3B, resist patterning was performed on the pattern of the pressurized liquid chamber. After that, the silicon nitride film 103 was etched (portion A) according to the resist pattern. Next, as shown in FIG. 3C, the silicon oxide film 102 was patterned (B portion) so as to dig Si to a depth of about 100 μm in the subsequent process. After that, as shown in FIG. 3D, the pattern resist of the communication hole was patterned, and the silicon nitride film 103 and the silicon oxide film 102 were sequentially etched (C portion). Since this patterning is anisotropically etched in a later step, it was formed in a substantially parallelogram shape so that the (111) plane appears. Next, as shown in FIG. 3E, patterning of Al was performed, and dry etching of silicon was performed using this Al as a mask to form a part (D portion) of the communication hole. After that, Al was removed as shown in FIG. 3F, and etching was performed with an aqueous solution of potassium hydroxide to penetrate the communication hole 16. After that, as shown in FIG. 3G, the silicon oxide film 102 was removed using the silicon nitride film 103 as a mask. Then, (h) of FIG.
As shown in, etching was performed with an aqueous potassium hydroxide solution to create the pressurized liquid chamber 17. Finally, as shown in (i) of FIG. 3, the silicon nitride film 103 and the silicon oxide film 102 were removed to form a flow path plate of the inkjet head. An inclined portion 24 is formed at the connecting portion between the pressurized liquid chamber 17 and the communication hole 16 by the above-mentioned two times anisotropic wet etching, and the inclined portion 24 prevents bubbles from accumulating to form a highly reliable inkjet head. We were able to.

FIG. 4 is a sectional view showing a manufacturing process of an ink jet head according to a second embodiment of another invention. First, as shown in FIG. 4A, a silicon substrate (110) 101 having a thickness of 400 μm was prepared, and a silicon oxide film 102 having a thickness of 1.0 μm and an LP-CVD nitride film 103 having a thickness of 0.2 μm were formed. . Next, as shown in FIG. 4B, a resist pattern for a wet etching mask for forming the communication hole 16 was formed on the nozzle surface side. Then, the silicon nitride film 103 is formed according to the resist pattern.
Then, the silicon oxide film 102 was etched (portion A). Next, as shown in FIG. 4C, the silicon nitride film 103 was patterned (B portion) in the pattern of the pressurized liquid chamber 17. Thereafter, as shown in FIG. 4D, resist patterning was performed on the pattern of the communication holes 16 to etch the silicon oxide film 102 (C portion).
Since this patterning is anisotropically etched in a later step, it was formed in a substantially parallelogram shape so that the (111) plane appears. Next, as shown in (e) of FIG. 4, Al was patterned, and using this Al as a mask, silicon was dry-etched to form a part (portion D) of the communication hole. Then, Al is removed as shown in FIG. 4 (f), and etching is performed with an aqueous potassium hydroxide solution.
The communication hole 16 was penetrated. After that, as shown in FIG. 4G, the silicon oxide film 102 was removed using the silicon nitride film 103 as a mask to form a pressurized liquid chamber pattern mask (E portion). Subsequently, as shown in (h) of FIG. 4, etching was performed with an aqueous potassium hydroxide solution to create the pressurized liquid chamber 17. Finally, as shown in FIG. 4I, the silicon nitride film 103 and the silicon oxide film 10 are
2 was removed to form the flow path plate of the inkjet head. The inclined portion 25 is formed on the nozzle surface side of the communication hole 16 by the anisotropic wet etching twice. After that, by arranging the nozzle hole 15 above the inclined portion 25, it was possible to prevent the retention of bubbles and form a highly reliable inkjet head.

FIG. 5 is a sectional view showing a manufacturing process of an ink jet head according to a third embodiment of another invention. First, as shown in FIG. 5A, a silicon substrate (110) 101 having a thickness of 400 μm was prepared, and a silicon oxide film 102 having a thickness of 1.0 μm and an LP-CVD nitride film 103 having a thickness of 0.2 μm were formed. . Next, as shown in FIG. 5B, resist patterning was performed on the pattern of the pressurized liquid chamber.
Then, according to the resist pattern, the silicon nitride film 1
03 etching (A part) was performed. Next, as shown in FIG. 5C, the silicon oxide film 102 was patterned so as to dig Si to a depth of about 100 μm in the subsequent process. Then, as shown in FIGS. 5D and 5E, resist patterning (B portion) was performed on the pattern of the communication holes, and the silicon nitride film 103 and the silicon oxide film 102 were sequentially etched (C portion). . Since this patterning performs anisotropic etching in a later process, (1
11) It was performed in a substantially parallelogram shape so that the surface appears.
Next, as shown in FIG. 5F, Al was patterned, and using this Al as a mask, silicon was dry-etched to form a part (D portion) of the communication hole. Then, Al is removed as shown in FIG.
6 was penetrated. Then, as shown in FIG. 5H, the silicon oxide film 10 is formed using the silicon nitride film 103 as a mask.
2 was removed to form a mask pattern (portion E) for the pressurized liquid chamber. Then, as shown in (i) of FIG.
7 was created. Finally, as shown in FIG. 5 (j), the silicon nitride film 103 and the silicon oxide film 102 were removed to form a flow path plate of the inkjet head. In this embodiment, ink channels are formed on both the nozzle surface side and the pressurized liquid chamber side. By forming ink channels on both the upper and lower sides, the height of the pressurized liquid chamber can be lowered, and it is not affected by crosstalk, and ink supply is sufficiently possible even in multi-driving and high-frequency driving. It is possible to form quality inkjets. In addition, the pressurized liquid chamber 17 is formed by the anisotropic wet etching performed twice.
The inclined portion 24 was formed at the connecting portion of the communicating hole 16 with the inclined portion 24, and the inclined portion 24 prevented the retention of bubbles and was able to form a highly reliable inkjet head.

It is needless to say that the present invention is not limited to the above embodiments, and various modifications and substitutions can be made within the scope of the claims.

[0022]

As described above, in the ink jet head of the present invention, the nozzle forming member having a plurality of nozzles, the pressurized liquid chamber forming member communicating with the nozzles, and the displacement of the electromechanical conversion element are converted into ink. The pressurizing liquid chamber forming member is provided with at least a pressurizing liquid chamber and a communication hole connecting the pressurizing liquid chamber and the nozzle. Further, the connecting portion between the pressurized liquid chamber and the communication hole in the pressurized liquid chamber forming member is provided with an inclined portion in which the cross section of the pressurized liquid chamber becomes larger toward the communication hole. Therefore, it is possible to provide a highly reliable ink jet head in which ink can flow from the pressurized liquid chamber to the communication hole without stagnation and a nozzle bit defect due to bubble generation does not occur.

Further, according to another aspect of the invention, an ink jet head is provided with an inclined portion in which the diameter of the communication hole increases as it gets closer to the nozzle, at the joint between the communication hole and the nozzle in the pressurized liquid chamber forming member. There is. Therefore, it is possible to provide a highly reliable inkjet head in which the ink flow from the end of the communication hole to the nozzle plate can be performed without stagnation and a nozzle bit defect due to bubble generation does not occur.

Further, it is desirable that the pressurized liquid chamber forming member is made of silicon.

Further, according to another method of manufacturing an ink jet head, the resist pattern formed by patterning the pattern resist of the communicating hole communicating with the nozzle is not etched through the substrate by dry etching. It is characterized in that it has a step of performing a substantially parallelogram shape and a step of thereafter performing processing by anisotropic wet etching to form an inclined portion on the nozzle side and / or the ink conversion liquid chamber side of the communication hole. . Therefore,
Throughput is poor with dry etching alone, but throughput can be improved by using it together with wet etching, and ink flow to the pressurized liquid chamber and / or communication hole and / or communication hole and nozzle plate can be performed without stagnation. It is possible to provide an inkjet head manufacturing method capable of manufacturing a highly reliable inkjet head in which a nozzle bit defect due to bubble generation does not occur.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an overall configuration of an inkjet head according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of a flow path plate in the inkjet head of this embodiment.

FIG. 3 is a cross-sectional view showing the manufacturing process of the inkjet head according to the first embodiment of another invention.

FIG. 4 is a cross-sectional view showing a manufacturing process of an inkjet head according to a second embodiment of another invention.

FIG. 5 is a cross-sectional view showing a manufacturing process of an inkjet head according to a third embodiment of another invention.

[Explanation of symbols]

11; nozzle plate, 12; flow path plate, 13; vibrating plate, 14;
Actuator plate, 15; Nozzle, 16; Communication hole, 1
7; Pressurized liquid chamber, 18; Common liquid chamber, 19; Beam part, 20; Island-shaped convex part, 21; Thinnest film part, 22; Drive part, 23; Non-drive part, 24, 25; Inclined part, 101 ; Silicon substrate, 1
02: silicon oxide film, 103: silicon nitride film.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kiyoshi Yamaguchi             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh F-term (reference) 2C057 AF77 AG12 AG29 AP32 AP33                       BA04 BA14

Claims (4)

[Claims] 1. A nozzle forming member having a plurality of nozzles, a pressurized liquid chamber forming member communicating with the nozzle, and an actuator member for propagating displacement of an electromechanical conversion element to the ink converting liquid chamber. In the inkjet head, at least a pressurizing liquid chamber and a communication hole that connects the pressurizing liquid chamber and the nozzle are formed in the pressurizing liquid chamber forming member, and the pressurizing liquid chamber forming member includes the pressurizing liquid chamber forming member. An inkjet head, wherein a connecting portion between the pressure liquid chamber and the communication hole is provided with an inclined portion in which a cross section of the pressure liquid chamber increases as it approaches the communication hole. 2. A nozzle forming member having a plurality of nozzles, a pressurized liquid chamber forming member communicating with the nozzle, and an actuator member for propagating the displacement of the electromechanical conversion element to the ink converting liquid chamber. In the inkjet head, at least a pressurizing liquid chamber and a communication hole connecting the pressurizing liquid chamber and the nozzle are formed in the pressurizing liquid chamber forming member, and the communication in the pressurizing liquid chamber forming member is performed. The inkjet head is characterized in that an inclined portion whose diameter of the communication hole increases as it approaches the nozzle is provided at a joint between the hole and the nozzle. 3. The ink jet head according to claim 1, wherein the pressurized liquid chamber forming member is made of silicon. 4. A nozzle forming member having a plurality of nozzles, a pressurized liquid chamber forming member communicating with the nozzle, and an actuator member for propagating the displacement of the electromechanical conversion element to the ink converting liquid chamber. In an inkjet head manufacturing method for manufacturing an inkjet head, a resist pattern formed by patterning a resist pattern of a communication hole communicating with the nozzle is formed into a substantially parallelogram shape so as not to penetrate the substrate by dry etching. And the wet etching is then performed to form an inclined portion on the nozzle side of the communication hole and / or on the ink conversion liquid chamber side.