JPH07132595A - Ink jet head and production thereof - Google Patents

Abstract

PURPOSE:To inexpensively provide an ink jet head suitable for miniaturization and densification and high in ink emitting response. CONSTITUTION:In an ink jet head having a plurality of ink pressure chambers 101 communicating with an ink sump 103 at one end thereof through ink supply passages 102 and communicating with nozzles 10a emitting ink droplets at the other ends thereof, spaces 102a, 101a substantially determining the volumes of the supply passages 102 and the pressure chambers are provided to a single crystal silicon base material 100 having the surface of a crystal surface azimuth (110). The space 102a becomes the supply passage 12 having two (111) surfaces inclined with respect to the surface of the silicon base material 100 as wall surfaces and the space 101a becomes the pressure chamber 101 having at least two (111) surfaces vertical to the surface of the silicon base material as wall surfaces.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording provided with a nozzle for ejecting ink, an ink pressure chamber communicating with the nozzle for applying a pressure to the ink, and a pressure generating means for changing the pressure in the ink pressure chamber. The present invention relates to a recording head of an apparatus and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, as demands for high-speed, high-density, low-cost ink jet recording apparatuses have increased, various measures have been proposed to realize them. Further, in accordance with the demands for high speed, high density, and low price, the ink flow path including the ink supply path, the ink pressure chamber, and the nozzle is provided in Japanese Patent Publication No. 4-1.
5095, etc. Measures by the photosensitive resin,
Various measures have been proposed, such as a measure by anisotropic etching of a silicon base material.

An ink jet head having an ink flow path formed of a silicon base material is shown in FIG.
No. 40509 is known, and in this example, a silicon base material whose surface has a crystal plane orientation of (100) is used.

On the other hand, KI Petersen's "Fabricatin of an
Integrated, Planar Silicon Ink-Jet Structure ”IEE
E transactions on electron devices, vol.ED-26, N
o.12, December 1979 (11
An inkjet head using a silicon base material (0 surface) is disclosed.

Further, US Pat. No. 4,312,008 also discloses an ink jet head using a silicon substrate having a (110) plane.

[0006]

In order to realize a practical ink jet printer using the above conventional example, the following problems occur.

First of all, in the measures by injection molding of a resin and the measures using a photosensitive resin described in Japanese Patent Publication No. 4-15095, the injection molding requires releasability and the photosensitive resin requires accuracy. In order to ensure this, the ink pressure chamber cannot be deepened, the flow path resistance increases, and the responsiveness deteriorates.

Further, since the ink pressure chamber is made of resin as described above, the side wall separating the adjacent ink pressure chambers is deformed by the ink ejection pressure, and mutual interference called crosstalk occurs. Will end up.

Secondly, in the (100) plane silicon base material 81 described in Japanese Patent Publication No. 58-40509,
The (111) plane that appears by etching is the (10)
Since it has an inclination with respect to the (0) plane, the width-depth ratio of the ink flow path cannot be increased beyond a certain level. Above all, the ink pressure chamber 82, which needs to be deep to obtain a sufficiently large volume, has a side wall of tan ^{−1 with} respect to the surface of the silicon substrate.
Since it is inclined at an angle of √2 (approximately 54.7 °), it has a trapezoidal or triangular (V-shaped) cross-sectional shape shown in FIG. It is not a suitable measure for the head.

Thirdly, by anisotropic etching of the (110) plane silicon substrate 91 shown in FIG. 9, a deep ink pressure chamber 93 can be formed. It is easy to obtain a high response even if the ink flow paths are arranged at a high density. However, in this example, the ink supply path 92
Is formed on a member different from the silicon base material 91, and the volume (cross-sectional area and length) of the ink supply passage 92 changes depending on the positional accuracy of the bonding. In order to stabilize the ejection characteristics of ink droplets by narrowing the cross-sectional area of the ink supply passage 92, which is generally performed, a high-level assembly technique is required, and the ink pressure chamber 93 and the ink supply passage 92 are formed. Since a step is formed at the connecting portion, the ability to discharge bubbles in the ink flow path is impaired, which is a cause of ejection failure.

Fourthly, in the method disclosed in US Pat. No. 4,312,008, a silicon substrate having a (110) plane is provided with an ink pressure chamber having a trapezoidal or rectangular cross section, and a cross section. It is not possible to form a V-shaped nozzle and an ink supply path in combination.

Therefore, an object of the present invention is to provide a flow path made of silicon, which simultaneously has an ink pressure chamber having a sufficiently large volume and a stable ink supply path having a width (and thus volume) of the supply path. Since a base material is obtained, downsizing,
It is an object to provide an inkjet head, which is optimal for high density and has high ink ejection response, at a low price.

[0013]

That is, according to the present invention, as an ink jet head for solving such a problem, a single crystal silicon substrate having a crystal plane orientation (110) surface as a surface is provided with the above-mentioned supply path. A space for substantially determining the volume of two parts of the pressure chamber, and a space for the supply path having two (111) planes inclined with respect to the surface of the base material as wall surfaces; And a space of the pressure chamber having at least two (111) planes perpendicular to the surface of the silicon base material as wall surfaces.

Further, in the method of manufacturing an ink jet head for realizing the constitution, (1) the single crystal silicon base material having a crystal plane orientation (110) plane is formed by an etching solution whose etching rate depends on the crystal orientation. A first space having two (111) planes inclined to the (110) plane on the wall surface, and a second space having at least two (111) planes on the wall surface perpendicular to the (110) plane. And anisotropically etching step (2) and after that,
And a step of removing a partition wall composed of a (111) plane and partitioning the first space and the second space.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS In order to describe the present invention in more detail, it will be explained with reference to the accompanying drawings.

In this embodiment, the resolution is 360 dpi (dot / inc).
In order to realize the printer of h), a plurality of 180 dpi nozzles are arranged in two rows.

FIG. 1 is an exploded perspective view showing an example of an ink jet head to which this embodiment is applied. As shown in FIG. 1, the mounting hole 17 penetrating the inside of the head frame 12 is
A base member 5, which will be described later, is held in order to position the piezoelectric transducer 1, which is a pressure generating means, in the X-axis and Y-axis directions. The longitudinal end surface of the piezoelectric transducer 1 has a vibrating plate 11 including a vibrating film 11a and a rigid protrusion 11b, a flow path base material 100, and a nozzle base material 1 on which a nozzle 10a is formed.
The bonded bodies that are stacked in the order of 0 are bonded to the rigid protrusion 11b, and the positioning in the Z-axis direction is obtained (see FIG. 4).

FIG. 2 is an enlarged view of the main part of the ink jet head of this embodiment.

The flow path substrate 100 has a crystal plane orientation of (11
It is a single crystal silicon having a (0) plane. The silicon base material 100 is subjected to so-called anisotropic etching in which the etching rate is dependent on the crystal orientation for etching with an etching solution, that is, the ink pressure chamber 101, the ink supply path 102, and the ink reservoir 103 (hereinafter referred to as the pressure chamber 101, the supply chamber, respectively). Spaces 101a, 102a, and 103a that substantially determine the volume of the ink flow path including the path 102 and the reservoir 103)
It has and. Although not shown in the figure, the surface of the ink flow path is conditioned by a protective film obtained by adding impurity atoms to silicon such as diffusion treatment of oxygen atoms by heat to improve resistance to ink and affinity with ink. ing. The above-mentioned protective film is not always essential for achieving the object of the present invention, and can be suppressed to a range that causes no problem in practical use by selecting and optimizing the ink to be used.

The supply passage 102 has a triangular cross section (V-shape) and is smaller than the rectangular pressure chamber 101. This changes the flow path resistance of the supply path 102 to the pressure chamber 10
It is set to be larger than 1 to effectively improve the ejection efficiency of ink droplets, and the amount of ink flowing into the nozzle 10a at the time of ejection is increased, and at the same time, the reservoir 103 from the supply path 102.
The amount of ink flowing out to is reduced.

A space 101a which becomes the pressure chamber 101
Is a parallelogram surrounded by the (111) plane parallel to the crystal axis orientation <211> axis, and the space 102a serving as the supply path 102 is inclined parallel to the <110> axis (11
1) It consists of faces. The space 102a serving as the ink supply path 102 is disposed at the corner of the space 101a serving as the pressure chamber 101 on the acute side of the parallelogram to facilitate the flow of ink and the discharge of bubbles.

The nozzle substrate 10 is bonded to one surface of such a silicon base material 100, and the vibration plate 11 is bonded to the other surface thereof to form the pressure chamber 101, the supply passage 102, and the reservoir 103. It

The ink is supplied to the pressure chamber 101 in a communicating relationship with the ink supply pipe 13, the ink communication port 14, and the reservoir 1.
03 and the supply path 102 (see FIG. 1).

FIG. 3 is a perspective view of the ejection force generating means of the ink jet head to which this embodiment is applied.

The pressure generating means for ejecting ink as droplets is the piezoelectric converter 1, which has a multilayer structure in which the piezoelectric bodies 2 and the internal electrodes 3a, 3b are alternately stacked. Further, external electrodes 4a and 4b are formed on the piezoelectric converter 1, and the external electrode 4a is electrically connected to the internal electrode 3a, and the external electrode 4b is electrically connected to the internal electrode 3b. Further, approximately half of the piezoelectric transducer 1 in the longitudinal direction is joined to (the base electrode 6 on) the base member 5, and the other half of the tip which is not joined is joined to the diaphragm 11 as described above. (See Figure 2). By using such a laminated type, a large displacement can be obtained at a low voltage. Further, by using the longitudinal vibration type vibrator, a higher pressure can be generated as compared with the flexural vibrator, so that the silicon substrate 1
The advantage of high density in 00 can be fully utilized.

In this structure, the ink droplet ejection operation is as shown in FIGS. Piezoelectric converter 1
Although not shown in FIG. 4, the drive wiring that drives the first and second internal electrodes 3a, 3a formed on the piezoelectric transducer 1
b, the operation signal is input through the base electrode 6 and the first and second external electrodes 4a and 4b also formed on the piezoelectric converter 1.

The piezoelectric transducer 1 is in a standby state in the normal state as shown in FIG. 4A, but when a voltage is applied to the piezoelectric transducer 1 as shown in FIG.
While contracting in a direction orthogonal to (Z-axis direction in FIG. 1), the diaphragm 11 is pulled through the rigid protrusion 20b to increase the volume of the pressure chamber 101. At this time, the ink 20 forms a meniscus in the nozzle 10a due to the surface tension, and the negative pressure generated by the increase in the volume causes the ink 20 filled in the reservoir 103 to flow through the supply passage 102 to the pressure chamber 1
It draws in 01. Next, when the voltage is rapidly released,
As shown in (c), the electric charge charged in the piezoelectric body 2 is rapidly discharged, and the tensile force of the piezoelectric converter 1 is lost. An elastic restoring force is generated between the piezoelectric transducer 1 and the diaphragm 11, and the volume of the pressure chamber 101 is rapidly reduced. Due to this decrease in volume, a positive pressure is generated in the pressure chamber 101, and the ink droplet 20a is ejected from the nozzle 10a. The piezoelectric transducer 1 returns to the standby state shown in FIG. 4A again and stands by for the next operation signal.

In the present embodiment, the size of the piezoelectric transducer 1 is set to 80 in the arrangement direction (X-axis direction in FIG. 1).
μm, array pitch of individual piezoelectric transducers in array direction is approximately 1
41 μm, the thickness in the stacking direction is about 0.5 mm, the stacking pitch in the stacking direction, that is, the distance between internal electrodes is about 20 μm, the length in the longitudinal direction (Y-axis direction in FIG. 1) is about 8 mm, and the inner stacking length is about It was set to 5 mm. With this size, the internal electrodes 3a, 3b are approximately 2
By applying a voltage of 0 V, a displacement of 2 μm or more and a pressure of 300,000 Pascal can be obtained at the non-bonded end of the piezoelectric transducer, and finally an ink drop of about 0.1 μg
It was possible to eject at a response frequency of kHz.

Further, in the ink jet head having such a structure, when the flow path substrate is made of a resin such as a photosensitive resin, the rigidity of the resin is low, so that the pressure chamber 101 adjacent to the pressure chamber 101 is separated by the ejection pressure of the ink. The side wall may be bent or the entire flow path substrate 100 may be deformed in the thickness direction.
As a result, the amount of ink droplets is reduced, and so-called crosstalk in which ink is ejected from the nozzles 10a to which an operation signal is not input occurs, resulting in deterioration of ink ejection performance. However, since the flow path base material made of silicon of the present invention has much higher rigidity than resin, the above problem did not occur at all.

A manufacturing method for realizing the above configuration of the present invention will be described below.

FIGS. 5A to 5D show an embodiment of the manufacturing process of the present invention.

First, the single crystal silicon base material 100 whose surface crystal plane orientation is the (110) plane is heated to 900 to 1100 ° C.
It is then heated and placed in a high-temperature gas of oxygen, water vapor, and other oxidizing agents to diffuse oxygen atoms on its surface. In this example, a silicon oxide film 200 having a thickness of 1.7 μm was formed by this thermal oxidation treatment. The silicon oxide film 200 plays a role of a mask in an anisotropic etching process described later, and its forming means includes a CVD (chemical vapor deposition) method, an ion implantation method, in addition to the thermal oxidation treatment described above. The anodizing method may also be used. Besides the silicon oxide film, a silicon nitride film, a so-called p-type silicon film added with boron or gallium atoms, or a so-called n-type silicon film added with arsenic or antimony atoms may be formed. .

The thickness of the silicon substrate 100 is 0.1 to 0.1.
0.5 mm is preferable, and more preferably 0.15 to 0.
It is 3 mm. In this embodiment, a silicon base material 100 having a thickness of 0.18 mm is used.

Next, a resin resist is patterned on the silicon substrate, and the silicon oxide film 200 is selectively removed by an acid etching solution such as a hydrofluoric acid aqueous solution.

Next, when the resin resist is removed, FIG.
As shown in (a), the mask pattern of the silicon oxide film 200, which is patterned by the etching in the previous step, appears. The window portion 201 corresponds to the pressure chamber 101, the window portion 202 corresponds to the supply passage 102, and the window portion 2
03 is a part corresponding to the reservoir 103.

Next, the silicon substrate 10 is treated with an etching solution whose etching rate changes depending on the crystal orientation of an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide.
0 is anisotropically etched. The anisotropic etching of the silicon base material 100 is performed through the process shown in FIG.
The process ends in the state shown in (c). That is, as shown in FIG. 5B, the anisotropically etched window 201 has a (111) plane perpendicular to the (110) plane of the surface of the silicon substrate 100 and an inclined (111) plane. Is expressed. On the other hand, the inclined (111) plane is also developed in the window. When anisotropic etching is further advanced, as shown in FIG. 5C, the oblique (111) plane of the window 201 disappears and a vertical (111) plane is newly developed. Through the above steps, the through space 101a that substantially determines the volume of the pressure chamber 101, the non-through space 102a that substantially determines the volume of the supply passage 102, and the through space that substantially determines the volume of the reservoir 103. The created space 103a is vertical (11
1) It is formed by being divided into the surface 204.

In this embodiment, the silicon substrate 100 is anisotropically etched with a 20% by weight aqueous solution of sodium hydroxide heated to 80 ° C., and the silicon substrate 100 is dipped for about 90 minutes as shown in FIG. A shape as shown was obtained.

Next, a partition wall 204a composed of the above-mentioned vertical (111) plane and partitioning the space 101a serving as the pressure chamber 101 and the space 102a serving as the supply passage, and the space 102a serving as the supply passage and the reservoir portion are formed. The partition wall 204b that separates the space 103a that becomes the space 103a is removed by an isotropic etching solution such as a hydrofluoric acid solution. The isotropic etching solution also removes the silicon oxide film 200 at the same time, and the removal rate is almost the same as that of the silicon base material 100.
Therefore, the thickness of the partition wall 204 in this example is 1.7 μm, which is the same as the thickness of the silicon oxide film 200. Further, as another means for removing the partition wall 204,
Means for removing by shock such as ultrasonic vibration is also effective.

Next, a protective film (not shown) is formed in order to obtain resistance to the ink and affinity with the ink. The type of film to be formed and the forming means are the same as the mask pattern 2 described above.
Although it is the same as the process of No. 00, it is most preferable to form the protective film of silicon oxide by thermal oxidation treatment.

In this way, the space 101a and the space 102
In the process of forming a and the partition wall 204 (204a and 204a
By providing b), it is possible to prevent excessive etching of the acute angle portion of the parallelogram, which is secondary to anisotropic etching, and as a result, the space 101a and the space 102a are accurately formed into a desired shape. We were able to.

Further, since the supply passage 102 and the pressure chamber 101 are integrated in the same component (silicon base material 100),
By utilizing the shape accuracy, which is an advantage of silicon etching, it was possible to reduce variations in ejection characteristics among a plurality of ink channels and variations among manufacturing lots. Etching rate is slower than other crystal orientation planes (111)
Since only the surface remains, the permissible range of condition variation in the anisotropic etching step is wide, and very stable shape quality can be secured.

FIG. 6 is a perspective view showing an essential part of an ink jet head showing another embodiment of the present invention. A plurality of supply paths 102 are provided for one pressure chamber 101, and in this embodiment, two supply paths 102 are provided.
In addition, in the present embodiment, the space 101a serving as the pressure chamber 101 is provided at the corners on one of the acute and obtuse sides of the parallelogram.
Since the two spaces 102a serving as the supply paths 102 are arranged, the flow of ink and the discharge of bubbles can be further improved.

FIG. 7 is a perspective view showing a main part of an ink jet head showing still another embodiment of the present invention.
In this embodiment, the space 1 that substantially determines the volume of the nozzle
04a is also formed in the same manner as the space 102a of the supply path 102, and is a suitable application example to a so-called edge eject type recording head in which the nozzle 104 is arranged on the peripheral edge of the silicon base material 100. In order to arrange the plurality of nozzles 104 on one surface, the peripheral edge portion 100a is finished flat by a cutting means such as a rotary grindstone blade.

As described above, the plurality of ink supply paths 102 can be stably formed with desired flow path resistance, and the ink pressure chamber 101 having a sufficiently large volume can be formed at the same time so as to be formed on the silicon substrate 100. did it. Further, although the silicon of the flow path base material 100 is a fragile and easily damaged material, the plurality of ink supply paths 102 and the ink pressure chambers 101 are both supported by the adjacent ink supply paths 102 and 101. Since the beam-like structure can be used, the handling of the silicon base material 100 after forming the ink supply path 102 and the ink pressure chamber 101 can be simplified.

If a commercially available silicon wafer having a diameter of (110) and a diameter of 3 inches is used, the yield of 20 or more flow channel substrates 100 can be obtained at the same time. Therefore, the manufacturing time required for each flow channel substrate can be increased. The material cost is very low, and it can be manufactured at low cost.

[0046]

As described above, according to the configuration and method of the present invention, it is possible to sufficiently increase the volume of the ink pressure chamber and to provide an ink supply path having a stable width (and thus volume) of the supply path. At the same time, since the flow path substrate made of the silicon substrate that also has both properties can be obtained, it is possible to provide at low cost an inkjet head which is optimal for miniaturization and high density and has high ink ejection response.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an inkjet head to which an embodiment of the present invention is applied.

FIG. 2 is a perspective view of a main part of an inkjet head to which an embodiment of the present invention is applied.

FIG. 3 is a diagram showing pressure generating means of an inkjet head to which an embodiment of the present invention is applied.

FIG. 4 is a diagram showing an operation of the inkjet head of the present invention.

FIG. 5 is a manufacturing process diagram showing an embodiment of the manufacturing method of the inkjet head of the present invention.

FIG. 6 is a diagram showing another embodiment of the inkjet head of the present invention.

FIG. 7 is a diagram showing another embodiment of the inkjet head of the present invention.

FIG. 8 is a diagram showing a conventional technique.

FIG. 9 is a diagram showing a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Piezoelectric transducer 7 Adhesive 8a Flexible wiring board 8b Flexible wiring board 15 Supply pipe connection port 16 Control board 20 Ink 100 Flow path base material (single crystal silicon base material) 101 Ink pressure chamber (pressure chamber) 101a Ink pressure chamber Space for substantially determining volume 102 Ink supply channel (supply channel) 102a Space for substantially determining volume of ink supply channel 103 Ink reservoir (reservoir) 103a Space for substantially determining volume of ink reservoir 104 Nozzle 104a Space that substantially determines the volume of the nozzle 200 Silicon oxide film (mask pattern) 201 Mask pattern window part that is located in the ink pressure chamber 202 Mask pattern window part that is located in the ink supply path 203 Site in the ink reservoir Mask pattern window 204 Partition wall 204a Pressure chamber space and supply Partition wall 204b for partitioning the space of the channel 204b Partition wall for partitioning the space of the supply channel and the space of the reservoir

Claims (8)

[Claims] 1. An ink jet head having a plurality of ink pressure chambers, one end of which communicates with an ink reservoir via an ink supply path and the other end of which communicates with a nozzle for ejecting ink droplets. The surface of the single crystal silicon base material has a space that substantially determines the volumes of the two members of the supply path and the pressure chamber, and the two surfaces inclined with respect to the surface of the base material. A space of the supply path having a (111) plane as a wall surface and a space of the pressure chamber having at least two (111) planes as a wall surface that are perpendicular to the surface of the silicon substrate. Inkjet head to do. 2. The ink jet head according to claim 1, wherein the two (111) faces of the supply path formed on the base material form V-shaped grooves. 3. An ink jet head having a plurality of ink pressure chambers, one end of which communicates with an ink reservoir through an ink supply path and the other end of which communicates with a nozzle for ejecting ink droplets. The surface of the single crystal silicon substrate has a space that substantially determines the volumes of the two parts of the nozzle and the pressure chamber, and the two ( An ink jet system comprising: a space of the nozzle having a (111) plane as a wall surface; and a space of the pressure chamber having at least two (111) planes as a wall surface that are perpendicular to the surface of the silicon substrate. head. 4. The ink jet head according to claim 4, wherein the two (111) faces of the nozzle formed on the base material form a V-shaped groove. 5. A method for manufacturing an ink jet head having a plurality of ink pressure chambers, one end of which communicates with an ink reservoir through an ink supply path and the other end of which communicates with a nozzle for ejecting ink droplets. By the etching liquid whose is dependent on the crystal orientation, a first space having two (111) planes inclined to the surface of the single crystal silicon substrate having the crystal plane orientation (110) plane on the wall surface, Vertical,
Anisotropically etching a second space having at least two (111) planes on its wall surface; and (2) after that, the first space and the second space formed of the (111) planes A step of removing the partition wall for partitioning
And a method for manufacturing an inkjet head. 6. The first space is a space that substantially determines the volume of an ink supply path, and the second space is a space that substantially determines the volume of an ink pressure chamber. The method for manufacturing an inkjet head according to claim 5. 7. The first space is a space that substantially determines the volume of the nozzle, and the second space is a space that substantially determines the volume of the ink pressure chamber. The method for manufacturing an inkjet head according to claim 5. 8. The method according to claim 5, wherein the partition wall is removed by isotropic etching.